British Journal of Dairy Sciences 1(1): 10-25, 2010
ISSN: 2044-2440
© Maxwell Scientific Organization, 2010
Submitted Date: April 19, 2010
Accepted Date: May 01, 2010
Published Date: June 20, 2010
Why is there Still Rabies in Nigeria? - A Review of the Current and Future
Trends in the Epidemiology, Prevention, Treatment, Control and
Possible Elimination of Rabies
1
A.O. Adedeji, 2O.D. Eyarefe, 3I.O. Okonko, 4M.O. Ojezele, 5T.A. Amusan and 6M.J. Abubakar
1
Department of Veterinary Medicine, University of Ibadan, Ibadan, Nigeria
2
Department of Veterinary Surgery and Reproduction, Faculty of Veterinary Medicine,
University of Ibadan, Ibadan, Nigeria
3
Department of Virology, Faculty of Basic Medical Sciences, College of Medicine, University of
Ibadan, University College Hospital (UCH), Ibadan, 200005 Nigeria.
World Health Organization Polio Regional Reference Laboratory, World Health Organization
Collaborative Centre for Arbovirus Reference and Research, World Health Organization National
Reference Centre for Influenza, National Reference Laboratory for HIV and AIDS Research
4
Department of Nursing Science, Lead City University, Ibadan, Oyo State , Nigeria
5
Medical Laboratory Unit, Department of Health Services, University of Agriculture,
Abeokuta, Ogun State , Nigeria
6
Department of Microbiology, Federal University of Technology, Minna, Niger, Nigeria
Abstract: This study reports on why is there still rabies in Nigeria? Rabies is one of the most typical zoonosis
that has been well known since ancient ages. Rabies is endemic in Nigeria and remains an important public
health issue in Nigeria, West Africa. It is the most important typical and zoonotic disease in the country. Public
concern and fears are most focused on dogs as the source of rabies. Rabies is an acute infectious viral disease
that attacks the nervous system, leaving victims suffering from convulsions, paralysis, excessive salivation and
an aversion to water. There have been fewer than five known cases where recovery has occurred. Rabies kills
an estimated 35,000 per year, mostly in Africa, Asia and Latin America. Its occurrence in man and domestic
animals is well known but the importance of wild animals in its spread has not been determined. To date, no
effective medical therapy has been established for overt rabies. Preventive vaccination against rabies virus is
a highly effective method for preventing rabies in humans and animals. The rabies Post-Exposure Prophylaxis
(PEP), which is a serial vaccination against rabies starting as soon as possible after the patient was bitten by
a suspected rabid animal, is the only way to prevent death. In Nigeria where dog bites continue to be the main
mode of transmission of the disease to man, it remains a serious public health hazard. Despite proper
vaccination some animals do not reach the threshold. Contributing factors include human factors through
increased human activities, attitudes, and error; socioeconomic factors through major ecologic, environmental
and anthropogenic changes of the biosphere, changes in agricultural practices, poverty, hunting with dogs, and
increasing demands for meat; animal factors (through animal importation, host population increase, migration
of dogs, migration of stray animals, frequency of consumption of animal brain); and vaccines and vaccination
factors (low vaccination coverage by increasing nonimmune population and factor contributing to vaccine
failures) and other vaccine related problem. Therefore, the need for detailed epidemiological studies in Nigeria
together with surveillance, control, the vaccination of human and animals, and accurate data collection and
adequate reporting is emphasized.
Keywords: Continued endemicity, domestic animals, preventive vaccination, public health issue, rabies,
rabies virus, wild animal, zoonotic disease, Nigeria
INTRODUCTION
has been known for more than 4300 years (Takayama,
2005, 2008). Rabies remains a zoonotic viral disease that
affects human, domestic and wild animals. Rabies kills an
estimated 35,000 per year, mostly in Africa, Asia and
Latin America (Beard, 2001). It remains an important
Rabies originated about 3000BC from the word rabha
meaning violence. Rabies is one of the most typical
zoonosis that has been well known since ancient ages and
Corresponding Author: I.O. Okonko, Department of Virology, Faculty of Basic Medical Sciences, College of Medicine, University
of Ibadan, University College Hospital (UCH), Ibadan, 200005 Nigeria
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Br. J. Dairy Sci., 1(1): 10-25, 2010
accurate information about the host species involved,
which enables informed decisions to be made with regard
to the epidemiologic patterns and potential threats to
public and veterinary health (Markotter et al., 2006b). In
Nigeria rabies infections both in animals and humans are
grossly under reported (Fagbami et al., 1981). Though,
the epidemiology, virology, transmission, pathology,
clinical manifestations, diagnosis, and treatment of rabies
infection have been described extensively by many
authors. Yet the incidence of rabies is increasingly on the
high side. This study therefore, reports on why is there
still rabies in Nigeria?
public health issue in Nigeria, West Africa. It is the most
important zoonotic disease in the country. Public concern
and fears are most focused on dogs as the source of rabies
(Suzuki et al., 2008a, b). Rabies is a serious, acute, highly
contagious, and fatal disease marked by a long and
variable incubation period (Awoyomi et al., 2007).
It is an infectious viral disease of Central Nervous
System (CNS) leaving victims suffering from
convulsions, paralysis, excessive salivation and an
aversion to water and leading to death of affected animal
in most cases (Beard, 2001). Two types of rabies exist,
this include sylvatic and urban. In the sylvatic cycle, this
infection is maintained as an enzootic disease in several
species, such as foxes, raccoons, and bats (SalmónMulanovich et al., 2009). The disease is acute progressive
encephalitis characterized by changes in behavior like
agitation excitation and drooling of saliva. At first there
might not be any symptoms. But weeks, or even years
after a bite, rabies can cause pain, fatigue, headaches,
fever, and irritability. These are followed by seizures,
hallucinations, and paralysis. There have been fewer than
five known cases where recovery has occurred (Beard,
2001).
Rabies is mainly a disease of all warm-blooded
animals. Its occurrence in man and domestic animals is
well known but the importance of wild animals in its
spread has not been determined (Umoh and Belino, 2008).
Usually humans contract rabies through rabid animal bite.
However, human-to-human transmission of rabies virus
occurred through organ transplantations. Furthermore, the
virus is usually transmitted through the bite of an infected
animal; corneal transplantation from an infected donor
and viral inhalation however, may also result in infection
(Takayama, 2005).
It is caused by rabies virus (RABV), a bullet–shaped,
enveloped RNA virus 180-75 nm with projections and
helical nucleocapsid, one of the better known encephalitis
viruses of the family Rhabdoviridae and genus Lyssavirus
type 1 (Salmón-Mulanovich et al., 2009). The genus
Lyssavirus is differentiated into 7 genetically divergent
genotypes: classical Rabies virus (genotype 1), Lagos bat
virus (LBV; genotype 2), Mokola virus (MOKV;
genotype 3), Duvenhage virus (genotype 4), European bat
lyssavirus (genotypes 5 and 6), and Australian bat
lyssavirus (genotype 7). All but MOKV have been
isolated from bats. LBV and MOKV are each distributed
in Africa and are members of phylogroup 2 within the
genus Lyssavirus (Hayman et al., 2008). Because LBV
isolates (Markotter et al., 2006a) from African bats are
increasing. Recently, Hayman et al. (2008) determined
the prevalence of virus neutralizing antibodies against
LBV in bat populations in West Africa.
Host identity is rarely a problem in domestic animals,
but wildlife species show potential uncertainty, such as
demonstrated in the case reported by Markotter et al.
(2006b). One important aspect of disease epidemiology is
RESULTS AND DISCUSSION
Epidemiology of rabies in Nigeria: A thorough
description of rabies epidemiology depends on a
comprehensive surveillance program and application of
accurate molecular methods to discriminate among
different variants and the emergence of new foci
(Favoretto et al., 2006). Analysis of RABVs circulating in
any region with the highest rabies incidence will help in
establishing the true epidemiology of rabies (WHO,
2005). RABV is the prototype member of the family
Rhabdoviridae and the genus Lyssavirus (Tao et al.,
2009). It encodes 5 structural proteins: nucleoprotein,
phosphoprotein, matrix protein, glycoprotein, and RNAdependent RNA polymerase. The nucleoprotein (N) gene
has been extensively used for genetic typing and
evolutionary studies because of its relatively conserved
variation among reservoir-associated variants and
geographic lineages (Tao et al., 2009).
Rabies has a long history of occurrence throughout
Africa, spanning hundreds of years. At least four distinct
Lyssavirus species persist throughout the continent,
among carnivores, bats and other mammals. Besides a
prominent toll on humans and domestic animals, the
disease has an underappreciated role in conservation
biology, especially for such highly endangered fauna as
African wild dogs. Both Duvenhage and Lagos bat viruses
are adapted to bats, but their epidemiology, together with
Mokola virus, is poorly understood (Nel and Rupprecht,
2007). The fluorescent antibody test used as a diagnostic
test for rabies can only indicate the presence of lyssavirus
antigens and cannot distinguish between lyssavirus
genotypes. To identify a lyssavirus precisely, antigenic
typing or genetic characterization is necessary, but these
techniques are beyond the capability of most laboratories
responsible for rabies diagnostics in Africa (Markotter
et al., 2006b).
1950s era: History of rabies in Nigeria dated back to the
1950s. Lagos Bat Virus (LBV) was also isolated from
frugivorous bats (Eidolon helvum) in Nigeria in 1956
(Kemp et al., 1972; MMWR, 1983).
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Br. J. Dairy Sci., 1(1): 10-25, 2010
Table 1: Rabies in Nigeria from 1970-2007
Year
Human cases
Animals
Dogs
1970
129
52
1971
53
42
1972
44
23
1981
1
1983
1
1994
23
1995
108
380 1997
59
19
1998
41
36
1999
23
2
2
2000
46
2001
3
209
209
2005
5
5
2007
2
2
Source: Umoh and Belino (2008). Information in this review is based on
annual reports of the Nigerian veterinary departments, WHO statistics
and surveys conducted.
Keys: Individual years:
1971 - Included one farm animal
1972 - Included two farm animals
1995 - 380 cases of laboratory-confirmed rabies (99.5% dogs), and
1,540 of clinically-confirmed rabies were reported. All cases
were contracted from dogs (Table 1)
1997 - Included two cats and two ruminants.
1997 - An outbreak (10 cases or more) of human rabies was reported in
Delta State (Table 1)
1960s era: Mokola virus (MOKV) was first isolated from
shrews (Crodidua spp.) in Nigeria in 1968 (Kemp et al.,
1972; MMWR, 1983). Also, in 1968, Kemp et al. (1972)
reported on the isolation of Kotonkan, a new rhabdovirus,
which related to Mokola virus of the rabies serogroup.
According Kemp et al. (1968), four rabies-related viruses
have been isolated, of which three may be new serotypes,
and further investigation of these were recommended.
These include: Kotonkan virus (IbAr 23380) represented
by a single isolate from Culicoides spp. collected at the
University of Ibadan Agricultural Farm, Nigeria, in
December 1967. Kotonkan virus (IbAr 23380) is a
chloroform-sensitive agent related to Mokola virus of the
rabies serogroup by complement fixation and fluorescentantibody tests but not by neutralization test (Kemp et al.,
1968).
1970s era: Subsequent cases of MOKV were reported in
humans in Nigeria in 1969 and 1971 (Kemp et al., 1972;
Ogunkoya et al., 1990). However, in Nigeria, where
MOKV was isolated for the first time, two human cases
with one death were reported. Two cases of (1 fatal) of
human Mokola (Lyssavirus subtype 3) were reportedly
claimed to have been isolated from Ibadan (Mokola
Forest) (Table 1). Le Gonidec et al. (1978) emphasized
the possibility of transmission of this virus by the bite of
an arthropod.
Kemp et al. (1972) reported serological evidence of
infection of dogs and man in Nigeria by lyssaviruses
(family Rhabdoviridae). Kemp et al. (1973) carried out
experimental infection and transmission studies on
Mokola virus with the shrew (a natural host for MOKV).
1990s era: In 1990, serological evidence of infection of
dogs and man in Nigeria by lyssaviruses (family
Rhabdoviridae) was reported by Ogunkoya et al. (1990).
In 1997, the last previous death from rabies in Britain was
also traced and linked to an infection Nigeria, where an
18-year-old London man contracted the disease during a
visit to Nigeria (WHO, 1997; Beard, 2001).
2000s era: In 2000, the retrospective dog rabies
vaccination at Ibadan was evaluated by Adeyemi (2000
reviewed in Awoyomi et al. (2007) showed that there is
still low response of dog owners to routine control of dog
rabies by immunization. In 2001 June 1, Beard (2001)
reported in the Independent Newspaper, The London, that
rabies claimed its second victim in a month in Britain
after the 51-year-old woman was bitten by a dog during a
trip to Nigeria to see relatives died from the disease on
Wednesday night in Lewisham hospital, south London,
where staff were seeking to reassure those who had come
into contact with her that the chances of catching rabies
were "infinitesimal". She was flown back to Britain and
admitted to hospital on Monday where doctors detected
symptoms of the disease, including fever, headache and
vomiting (Beard, 2001).
Ajayi et al. (2006) in a histological and
immunohistochemical studies reported the presence of
rabies in apparently healthy dogs. Also, in 2006,
Opaleye et al. (2006) reported the knowledge, attitude and
practices among residents of Osun State as the key factors
affecting the control of rabies in Nigeria. In their study
among 679 individuals, only 33.4% of the respondents
1980s era: In Tomori (1980) reported cases of wild life
rabies in Nigeria in an experimental infection and
transmission studies with the shrew (Crocidura sp.). In
1981, a case of rabies in Hungary was reported in a child
who had lived in Nigeria (Guseo et al., 1981). Also,
Fagbami et al. (1981) in their study on hospital of human
rabies and antirabies prophylaxis in Nigeria from 19691978 reported that rabies infections both in animals and
humans are grossly under reported in Nigeria.
Okoh (1982) reported cases of canine rabies in
vaccinated dogs in Nigeria from 1970-1980. According to
him, from 1970 through 1980, 14 cases of rabies in
vaccinated dogs were reported in various parts of Nigeria
(Okoh, 1982). Most cases of human rabies were acquired
from dogs. Its occurrence in man and domestic animals is
well known but the importance of wild animals in its
spread has not been determined. In 1983, a rabies case
was reported in the United States following a dog-bite in
Nigeria (MMWR, 1983). Okolo (1989) reported vaccineinduced rabies infection in rural dogs in Anambra State,
Nigeria.
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Br. J. Dairy Sci., 1(1): 10-25, 2010
interventions. The economics of using oral vaccines to
prevent rabies invading uninfected areas has yet to be
examined (Meltzer and Rupprecht, 1998a).
Asserting that rabies kills 100 children per day,
worldwide, the Alliance for Rabies Control acknowledged
that “rabies is also a concern for animal welfare, as fear of
the disease results in hostile and antagonistic attitudes
towards dogs and often inhumane approaches to dealing
with suspected rabid dogs by communities and
emphasized the need to expand dog vaccination against
rabies in Asia and Africa” (Clifton, 2007).
Animal rabies control consists of the vaccination of
dogs and cats, the elimination of stray animals, health
education for the public, etc. In some countries, mass
vaccination of dogs is not implemented, and the effective
coverage rate is not exactly known. The elimination of
stray dogs and other animals by shooting and poisoning is
still implemented in certain countries; however, this has
a minimal effect on rabies transmission (Seimenis, 2008).
Preventive vaccination against rabies virus is a highly
effective method for preventing rabies in humans and
animals (Jakel et al., 2008). For travel purposes,
vaccination of domestic carnivores is obligatory. In
addition, some countries require testing for neutralizing
antibodies against rabies. The minimal threshold level
accepted by WHO/OIE is 0.5 IU/ml. Despite proper
vaccination some animals do not reach the threshold
(Jakel et al., 2008).
“In Asia and Africa,” the Alliance for Rabies Control
points out, “the domestic dog is the main reservoir for
rabies. As rabies is generally maintained only in a single
reservoir population in any given area, control of disease
in this population will result in its disappearance from all
other species. This has been demonstrated with the
elimination of rabies following oral vaccination of foxes
in Western Europe, where red foxes are the reservoir host
(Clifton, 2007).
Despite the availability of effective human and
animal vaccines against rabies, and other measures for its
control, rabies continues to account for at least 55,000
human deaths each year, mainly in the developing
countries of Africa (Knobel et al., 2005). In these
countries, most human rabies infections result from
exposure to infected dogs, by bites, scratches, and
mucosal exposures (Cohen et al., 2007). Rabies
vaccination of animals and postexposure prophylaxis
(PEP) for humans is prohibitively expensive for most
African governments, and it has long been contended that
the effects of rabies are underestimated in Africa
(Cohen et al., 2007). Hilary Koprowski of Thomas
Jefferson University, according to Rupprecht and Tumpey
(2007), gave an overview of the historical aspects of
rabies and the current need for integrated technology to
eliminate canine rabies in the developing world such as
Nigeria.
knew rabies could be prevented by vaccination, while
38.7% believed that the infection could be treated with
herbs. Of the 387 victims of dog bite, 240 (62%) never
sought prophylactic postexposure treatment. Of the 10
people who received postexposure treatment, only one
received the appropriate treatment consisting of washing,
disinfection of wounds, tetanus toxoid and complete
antirabies immunization.
Awoyomi et al. (2007), in their study, pointed out the
socioeconomic factors associated with non-vaccination of
dogs against rabies in Ibadan, Nigeria. In 2008, to
investigate the presence of Lagos Bat Virus (LBV)specific antibodies in megachiroptera from West Africa,
Hayman et al. (2008) conducted fluorescent antibody
virus neutralization tests. Bats host a range of
lyssaviruses, depending on their species and locality.
Umoh and Belino (2008) gave a historical review of
rabies in Nigeria and reported further on the new rabiesrelated viruses isolated in Nigeria. According to Umoh
and Belino (2008), surveys of available serum specimens
collected in Nigeria disclosed neutralizing substance for
kotonkan virus in man, cattle, rodents and insectivores in
the north, and in cattle, sheep and horses in the south. In
their study, results of additional neutralization tests with
sera of newly imported cattle suffering a bovine
ephemeral fever-like illness, suggest a possible connection
between such outbreaks and kotonkan virus (Kemp et al.,
1968).
In March 29, 2009 ProMED-mail post, Woolf (2009)
reported on cases of rabies through dog or cat butchering
in Nigeria. A ProMED-mail post, a program of the
International Society for Infectious Diseases.
Notable outbreaks of rabies in Nigeria: Notable
outbreaks of rabies in Nigeria are shown in Table 1. Most
cases of human rabies in Nigeria were acquired from
dogs. Surveillance strategies for rabies viruses and other
rabies-ralated viruses in Nigeria must be improved to
better understand the epidemiology of this virus and to
make informed decisions on future vaccine strategies
because evidence is insufficent that current rabies
vaccines provide protection against these rabies-related
viruses (Markotter et al., 2006b).
Current trends in control, elimination and possible
eradication of rabies in Nigeria: Although rabies in
domestic and wild animals represents a significant threat
to public health and can cause economic losses among
livestock, there are very few studies that examine the
economics of rabies in animals. The literature that does
exist can be characterized as poorly documented estimates
of costs, with insufficient information to allow replication
of the analyses. Most papers have numerous 'violations' of
the standard recommended procedures for assessing
burden of disease and the cost and benefits of
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Br. J. Dairy Sci., 1(1): 10-25, 2010
consequences for human health in terms of morbidity and
mortality. Indirect implications are defined as the effect of
the influence of emerging zoonotic disease such as rabies
on two groups of people, namely: health professionals and
the general public. Professional assessment of the
importance of these diseases influences public health
practices and structures, the identification of themes for
research and allocation of resources at both national and
international levels (Meslin et al., 2000). The perception
of the general public regarding the risks involved
considerably influences policy-making in the health field.
However, other human factors affecting elimination of
rabies are:
In Nigeria where dog bites continue to be the main
mode of transmission of the disease to man, it remains a
serious public health hazard (Awoyomi et al., 2007).
Since dog has been established as the predominant vector
of rabies in Nigeria, the most logical and cost–effective
approach to rabies control is elimination of stray and
owner less dogs combined with a programme of single
mass immunization in the shortest possible time, at least
80% of the entire dog population (Awoyomi et al., 2007).
Although industrialized countries have been able to
contain recent outbreaks of zoonotic diseases, many
resource-limited and transitioning countries like Nigeria
have not been able to react adequately. The key for
controlling zoonoses such as rabies, echinococcosis, and
brucellosis is to focus on the animal reservoir (Zinsstag
et al., 2007). In this respect, ministries of health question
whether the public health sector really benefits from
interventions for livestock (Zinsstag et al., 2007).
Effective, practicable and acceptable control strategy can
only be put in place after the socio-economic facts
associated with dog owners in each community in Nigeria
have been studied.
Increasing travel: Rabies is a fatal disease, and increased
travel to rabies endemic areas, communities or villages is
one of the important factors influences the continual
endemicity of rabies in Nigeria. Moreover, visitors to
these communities and villages are sometimes unaware of
the rabies risk posed by dog bites and thus may not seek
appropriate medical attention for such bites. However,
travelers going to endemic areas need to take precautions
(Shaw et al., 2009).
Factors contributing to the continued endemicity of
rabies in Nigeria: The number of reported human rabies
cases, particularly in Africa, greatly underestimates the
true effects of the disease (Cohen et al., 2007).
Contributing factors include failure to seek treatment at
healthcare facilities, failure to make a laboratory
diagnosis, and failure to report the disease
(Coleman et al., 2004; Knobel et al., 2005; Cohen et al.,
2007). Dog rabies control relies principally on the mass
immunization of dogs in order to achieve population
immunity levels sufficient to inhibit rabies transmission
(Perry and Wandeler, 1993). In Nigeria and Africa
generally, such high levels of population immunity are
rarely achieved due to a number of reasons. Oral
immunization has been shown to be an effective means of
inducing high levels of immunity in fox populations in
several European countries, and this technique has been
mooted as a means of overcoming the logistical problems
of delivering injectable rabies vaccines to dogs (Perry and
Wandeler, 1993). Although highly effective if
administered correctly, PEP is much more costly than
vaccination of domestic
dogs (Rupprecht and
Gibbons, 2004; Cohen et al., 2007). Whether a virus
disease can be eradicated or not depends on many
factors (Tamashiro et al., 2007). The main factors that
contribute to the increase in the number of cases of rabies
and factors affecting elimination of rabies in Nigeria
include:
Lack of risk communication: Lack of risk
communication is one of the factors affecting rabies
elimination especially in Nigeria. Although, the boycott
of immunization is no longer in effect as in the case of
polio, low participation during vaccination may persist
reflecting a failure to implement risk communication
(Agbeyegbe, 2007). The silence of the government over
the alleged report by JNI and widely in the media that the
government acknowledged the use of contaminated
vaccines (as in the case of poliovaccines) but claimed that
the contaminated batch had been completely used could
be interpreted as indicative of the accurateness of the
report. To address such situations, risk communication is
increasingly becoming important in public health
(Rudd et al., 2003). Risk communication offers a two-way
communication process that presents the expert opinions
based on scientific facts to the public, and acknowledges
the fears and concerns of the public, seeking to rectify
knowledge gaps that foster misrepresentation of risk
(Leiss, 2004; Aakko, 2004; Agbeyegbe, 2007).
Lack of knowledge and information: This is one other
factor affecting rabies elimination especially in Nigeria
and has contributed to the continued endemicity of rabies
in Nigeria. Many countries, especially those with resource
constraints and those in sub-Saharan Africa, lack
information on the distribution of zoonotic diseases such
as rabies and rabies-related viruses (Zinsstag et al., 2007).
Risks for zoonoses are considered negligible compared
with those for diseases of higher consequence because the
societal consequences of zoonoses are not recognized by
Human factors: Meslin et al. (2000) described the direct
and indirect implications for public health of emerging
zoonoses. Direct implications are defined as the
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Br. J. Dairy Sci., 1(1): 10-25, 2010
have documented the costs associated with wildlife-rabies
epizootics (Shwiff et al., 2007; Sterner et al., 2009).
According to the Alliance for Rabies Control, “the tools
for effective rabies control are available. What is lacking
are the motivation, commitment and resources to tackle
the disease effectively (Clifton, 2007).”
the individual sectors. However, transmission of rabies to
humans can already be greatly reduced by health
information and behavior. Interventions in human and
livestock should always be accompanied by mass
information, education, and communication programs.
Lack of adequate public awareness: Lack of public
education campaigns is another factor affecting rabies
elimination in Nigeria. Though, public awareness of the
human health risks of zoonotic infections has grown in
recent years (Heeney, 2006), reliable data on rabies are
scarce in many areas of the country, making it difficult to
assess its full impact on human and animal health
(Awoyomi et al., 2007). Physicians in Nigeria can consult
colleagues, libraries, or data banks for help with puzzling
cases. At present, the networks do not address the
underlying causes of new and reemerging infectious
diseases. And they probably can do little to get to the
heart of the real issues: educating the public, immunizing
the children, improving sanitation, cleaning up the water,
housing the homeless, feeding the starving (Okonko et al.,
2008).
Lack of solid commitment and resourced initiatives:
Lack of solid commitment and resourced initiatives on the
part of the government of Nigeria is one other factor
affecting rabies elimination and this has contributed to the
continued endemicity of rabies in the country. In Nigeria,
little public domain information is available, but solid
commitment and resourced initiatives are still lacking.
However, in many areas in Nigeria, little is known about
the real cost of mass vaccination of dogs, and quantitative
data are urgently needed to evaluate the cost-effectiveness
of different rabies control strategies in Nigeria.
Inappropriate management: Inappropriate management
of rabies is another factor affecting rabies elimination in
Nigeria. The clinical signs and symptoms of the initial
rabies case-patients in Africa may have been altered due
to use of traditional medicines. As reviewed by
Cohen et al. (2007), the use of traditional medicines is
common in rural settings in Africa (Nigeria inclusive) and
may result in toxicities, including abdominal and
psychiatric symptoms and abnormal liver function test
results (Luyckx et al., 2004). These medicines could have
contributed to the atypical manifestations in some cases.
In addition, clinicians may have attributed some of the
neurologic symptoms to herbal intoxication (Cohen et al.,
2007). “In areas where there is a high prevalence of
rabies, such as Africa, the need for vaccination has often
been overlooked, despite the fact this would cost less than
other health care programs, including administering postexposure rabies immunization to save dog bite victims
(Clifton, 2007) reflecting inappropriate management.
Lack of good laboratory and proper surveillance: This
is another factor affecting rabies elimination in Nigeria.
Isolation of LBV from terrestrial wildlife in study
reported by Markotter et al. (2006a) serves as further
confirmation of our lack of understanding of the incidence
and host range of lyssaviruses in Africa. Poor surveillance
of rabies-related viruses and poor diagnostic capability in
most of area in Nigeria are large contributors to our lack
of information and the obscurity of the African
lyssaviruses. The lack of surveillance data on emerging
zoonoses as rabies means that the burden of human,
livestock and wildlife disease is underestimated and
opportunities for control interventions thereby limited.
Despite the availability of techniques to improve the
global rabies situation, limitations in surveillance and
epidemiologic investigations impede the institution of
such measures (Knobel et al., 2005; Nadin-Davis et al.,
2007). However, in Nigeria, laboratories continue to be
sadly behind the times in terms of equipment and skills
for diagnosing the emerging pathogens as can be readily
observed in Nigeria (Okonko et al., 2008).
Human attitudes and errors toward vaccination: This
is one other factors affecting rabies elimination especially
in Nigeria. In rural areas of Nigeria, nearly every family
owns several dogs, most of which are free roaming,
without special diets, and these dogs go unvaccinated
against rabies (to save costs). Free-roaming and
unvaccinated dog populations may increase the likelihood
of transprovincial or transregional as well as
transcommunity spread of RABVs.
Lack of appropriate control methods: Lack of
appropriate control methods is one of the factors affecting
rabies elimination especially in Nigeria. Lethal methods
of dog population control are even more expensive, and
attempting to control rabies by reducing dog populations
has not worked for any extended period (Meltzer and
Rupprecht, 1998b).
Poor attitude of vaccination record keeping: Poor
attitude to keeping of vaccination records is also another
factor affecting rabies elimination especially in Nigeria.
There is a poor attitude of record keeping among
Nigerians as it was practically impossible to obtain the
vaccination records for any vaccine preventable diseases
Lack of motivation: Lack of motivation is another factor
affecting rabies elimination in Nigeria. Several studies
15
Br. J. Dairy Sci., 1(1): 10-25, 2010
contributed to its continued endemicity in Nigeria.
Emergency preparedness planning for animal diseases
such as rabies is a relatively new concept that is only now
being applied in Africa (Roeder et al., 1999).
such as measles according to a study by Ogundiji (2008).
Vaccinees should be educated in all immunization
programs to keep their vaccination cards for future
reference. Virology Laboratories also should be equipped
with adequate test facilities to monitor post vaccination
seroconversion among subjects (Ogundiji, 2008).
Political instability and armed conflicts: Political
instability or armed conflicts is another factor affecting
rabies elimination and has contributed to its continued
endemicity in Nigeria. In several states particularly the
Niger Delta and the Northern States, political instability
or armed conflicts make vaccination logistically difficult
and unpredictable (Okonko et al., 2009). In addition to
this internal politics in the 2003 polio and measles
immunization boycott in Northern States in Nigeria, were
ramifications from the internal political arena. Antiwestern sentiments have increased among Northern
Muslims fundamentalist following the September 11,
2001 attacks and America’s war on terrorism. Given the
distrust and growing antagonism towards America, the
involvement of the West in a program that benefits
Muslims was viewed with suspicion (Agbeyegbe, 2007;
Okonko et al., 2009).
Gross under-diagnosis: This is another factor
responsible for the continued endemicity of rabies in
Nigeria and has affected the elimination of rabies in
NIgeria. The incidence of rabies in many parts of Africa
is unknown, but rabies is probably underdiagnosed
(Mallewa et al., 2007). Cases of rabies may be incorrectly
attributed to other causes of pyrexia and confusion
common to rural Africa, including cerebral malaria,
bacterial infections, and infection with HIV (Bleck and
Rupprecht, 2005; Mallewa et al., 2007; Cohen et al.,
2007). No investigations into infections of humans were
made during most investigations, but lyssavirus infections
in humans in Africa are underdiagnosed (Mallewa et al.,
2007; Hayman et al., 2008).
Gross under reporting: This is another factor
responsible for the continued endemicity of rabies in
Nigeria and has affected the rabies elimination especially
in NIgeria. Rabies is no doubt underreported and probably
misdiagnosed in Nigeria and elsewhere in Africa
(Asselbergs, 2007; Fagbo, 2009; Woolf, 2009). Quick,
decisive action to detect and control novel pathogens, and
thereby contain outbreaks and prevent further
transmission, is frequently hampered by incomplete or
inadequate data about a new or re-emerging pathogen
(Tapper, 2006). According to Ogundipe et al. (1989), in
their study the development and efficiency of the animal
health information system in Nigeria as well as the
completeness and immediacy of data supply by the
system for the period between January 1977 and
December 1984 revealed that the system was found to be
characterized by: late, inaccurate and gross under
reporting. And these constraints in reporting include
inadequate personnel, poor diagnostic and reporting
facilities (Okonko et al., 2008).
Conflict-Threat of armed militias and forced
Migration: Other challenges facing vaccination teams
included the threat of armed militias that roam the area in
search of opportunities to seize control over the local oil
resources in the Niger Delta (Njoku, 2006). According to
Okonko et al. (2008), with the overwhelming increase in
high-intensity of local conflicts among political, ethnic,
and religious rivals, government-based diseasesurveillance systems have little or no chance of success.
This has therefore affected rabies elimination and has also
contributed to its continued endemicity in Nigeria.
Cultural and religious beliefs: This is another factor
affecting rabies elimination and has contributed to its
continued endemicity in Nigeria. Cultural and religious
beliefs contribute to the underreporting of human rabies
that may arise from the consumption of infected
apparently healthy dogs and cats. The rabies-related
lyssaviruses (Lagos bat and Mokola viruses) still remain
under-diagnosed in the human populace (Fagbo, 2009;
Woolf, 2009). Most of the anti-immunization campaigns
in Nigeria have been predominantly Muslim north of
Nigeria, and a number of Muslim clerics have been
quoted in the Nigerian media as claiming that vaccines are
dangerous and cause sterility or illness (Adeija, 2007).
Cultural and religious objections under vaccinations
efforts, resulting in persistently low immunity in the
population and consequently, a high incidence of
emerging vaccine-derived viruses and reemergence of
wild viruses (Okonko et al., 2009). Whereas the
undercurrents between Muslims and Christians in Nigeria
as well as Western donors may have been sufficient to
begin the controversy on the vaccines as was seen in the
Poor coordination and cooperation: Poor coordination
and cooperation among federal government and some
states is another factor responsible for the continued
endemicity of rabies in Nigeria and has affected the rabies
elimination especially in NIgeria. Because animal disease
control, e.g. rabies control and ORV, is the responsibility
of each federal state, insufficient cooperation in the
planning of vaccination campaigns between neighbouring
federal states has also been an important shortcoming
(Müller et al., 2005).
Lack of emergency preparedness planning: This is
another factor affecting rabies elimination and has
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Br. J. Dairy Sci., 1(1): 10-25, 2010
expensive and they are not always used in all parts of the
world (Takayama et al., 1997). Industrialized countries
have (Klempner and Shapiro, 2004), but many resourcelimited and transitioning countries have not been able to
respond adequately and rapidly to recent zoonosis
outbreaks and contained them well because they lack
human and financial resources, and have not sufficiently
adapted public health surveillance. In industrialized
countries, an important part of successful zoonosis control
has been compensating farmers for culled livestock.
However, many Nigeria has not been able to conduct such
programs (Zinsstag et al., 2007).
case of polio vaccines, and other factors helped to sustain
it (Agbeyegbe, 2007).
Ignorance: Factors responsible for the continued
endemicity of rabies in Nigeria have also been attributed
to ignorance. This was clearly pointed out in a study by
Opaleye et al. (2006). Thus has affected rabies
elimination in Nigeria.
Government negligence: Government negligence is
another very important factor affecting elimination of
rabies in Nigeria and has also contributed to continued
endemicity of rabies in Nigeria. Deficiencies in national
veterinary services have contributed to failures in early
detection and response; in many regions investigation and
diagnosis services have deteriorated (Rweyemamu et al.,
2000). Also, the inability of the Nigerian government to
acknowledge the risk involved in vaccination however
negligible raises doubt about the sincerity of the
government, and positions the boycotts of vaccination (as
in case of polio) proponents as a more reliable source of
information (Olugbode, 2007; Okonko et al., 2009).
According to Olugbode (2007) and Okonko et al. (2009),
as no vaccine is fully safe, perfectly potent and without
risk of administering error (Clements et al., 1999), the
government does not appear to have positioned itself as a
credible authority to implement immunization programs.
Hunting with dogs: Hunting activities is another
scoioeconomic factor responsible for the continued
endemicity of rabies in Nigeria. The combination of urban
demand for bushmeat and greater access to primate
habitats provided by logging roads has increased the
amount of hunting in Africa countries; Nigeria inclusive,
which has increased the frequency of human exposure to
zoonotic diseases and other disease-causing agents such
as primate retroviruses (Chomel et al., 2007).
Increasing demands for meat: Increasing demands for
meat in Nigeria is one other socioeconomic factor
affecting rabies elimination and has contributed to its
continued endemicity in Nigeria. Another risk factor
related to the emergence of zoonotic diseases (such as
rabies) from wildlife has been the considerable increase in
consumption of bushmeat in this part of the world
(Karesh et al., 2005; Chomel et al., 2007). In Nigeria, dog
eating is very common in states such as Plateau, Akwa
Ibom, Cross River, Kaduna, Kebbi and Ondo. In fact, dog
suya (barbequed dog meat) is sold publicly in the dog
eating areas. In some areas such as Jos, only local and
seasoned connoisseurs may easily distinguish restaurants
where dog and other conventional meats are sold. Cat
eating, though not as common as dog eating, can also be
encountered, even in cosmopolitan places such as Lagos.
While human consumption of bats is also common, there
seems to have been little or no local effort (as per the
limited information available) to evaluate the risk of
rabies transmission (Durosinloun, 2009; Fagbo, 2009;
Woolf, 2009).
Government policy: This is another factor affecting
rabies elimination and this also contributes to its
continued endemicity in Nigeria. According to Zinsstag
et al. (2007), in resource-limited and transitioning country
as Nigeria, many zoonoses are not controlled effectively
because adequate policies and funding are lacking.
Nigerian government has not seen the need to make
tremendous dedication and policy in the health sector.
Deception: Deception is another factor affecting rabies
elimination and contributes to its continued endemicity in
Nigeria. According to Clifton (2007), policymakers in the
developing world often seek for their cities the
superficially animal-free appearance of a “modern” city
that they see in Europe and the U.S., equating this with
ridding themselves of rabies. But casual outdoor
observation of the country by daylight is deeply
deceptive.
Lack of good road network: Lack of good road network
is another important factor affecting elimination of rabies
in Nigeria and this also contributes to its continued
endemicity in Nigeria. Of the targeted 29 million children,
4 million reside in impoverished and hard-to-reach
settlements across the Niger Delta Region (Njoku, 2006).
Socioeconomic factors:
Poverty: Poverty is one major scoioeconomic factor
responsible for the continued endemicity of rabies in
Nigeria. Rabies in humans can be prevented by
appropriate postexposure prophylaxis, which is not;
however, always available and affordable in resourcelimited or resource-misused countries like Nigeria
(Zinsstag et al., 2007). Tissue-culture vaccines are
Animal factors:
Host population increase: Host population is one major
animal factor affecting rabies elimination and this has also
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Br. J. Dairy Sci., 1(1): 10-25, 2010
contributed to its continued endemicity in Nigeria. As in
a classic situation, outbreak of rabies in humans followed
an outbreak in domestic dogs of the Africa region.
Increasing numbers of human rabies cases in Africa have
been attributed to increasing numbers in animals
(Cohen et al., 2007). The pet dog and cat populations rose
proportionate to the human population. The pet dog
population had increased by just about exactly as much as
the street dog population declined (Clifton, 2007).
Vaccines and vaccination factors (by increasing
nonimmune population), including factors
contributing to low coverage: This is another major
factor affecting rabies elimination and contributes to its
continued endemicity in Nigeria. Vaccines are the basis of
the medical and veterinary medical future, the belief being
that, if a vaccine can be made to every disease, then all
disease can be prevented. This presupposes that 1) disease
attacks from outside and has nothing whatsoever to do
with the person or animal themselves; 2) that vaccines
actually always protect one hundred per cent; and 3) that
vaccines themselves are only beneficial and cannot cause
harm. None of these are true. There is a growing list of
research into and information on the problems that can be
caused by vaccines. There has been much debate on the
subject of annual pet vaccination, chiefly in response to
concerns voiced by pet owners. The veterinary profession
is largely unaware of the range of side effects vaccines
can stimulate, and consequently they go unreported.
Despite the availability of effective human and animal
vaccines against rabies, and other measures for its control,
rabies continues to account for at least 55,000 human
deaths each year, mainly in the developing countries of
Africa and Asia (Knobel et al., 2005). In these countries,
most human rabies infections result from exposure to
infected dogs, by bites, scratches, and mucosal exposures
(Cohen et al., 2007). Rabies vaccination of animals and
postexposure prophylaxis (PEP) for humans is
prohibitively expensive for most African governments,
and it has long been contended that the effects of rabies
are underestimated in Africa (Cohen et al., 2007). A
radical rethink of the vaccination programme is necessary
- immunization programmes need not be abandoned, but
reassessed.
Migration of dogs: Migration of dogs is one other major
animal factor affecting rabies elimination and this has also
contributed to its continued endemicity in Nigeria. This
has been previously pointed out that in several studies
that, “outbreak of rabies in humans followed an outbreak
in domestic dogs”. Increasing numbers of human rabies
cases in Africa, Nigeria inclusive, have been attributed to
the mobility of human and animal populations
(Cohen et al., 2007). Other human-related activities, such
as persons migrating with their dogs may also contribute
to long-distance spread of rabies. While the majority of
reported potential rabies exposures are associated with
dog and cat incidents in most places, most rabies
exposures have been derived from rabid wildlife
(Roseveare et al., 2009).
Migration of stray animals: This is another factor
responsible for the continued endemicity of rabies in
Nigeria. According to Roseveare et al. (2009), stray cats
were most frequently rabid among domestic animals. In
Nigeria, we have so many stray dogs and cats all over the
cities and there is no mass vaccination programme for
such animals. This underscores the need for improvement
of wildlife rabies control and the reduction of interactions
of domestic animals, including cats, with wildlife in
Nigeria.
Low vaccination coverage: This is a major vaccine and
vaccination factor responsible for the continued
endemicity of rabies in Nigeria. The single most
important factor affecting eradication of rabies is the
failure to immunize domestic dogs, which transmit rabies
to humans (Fu, 2008). Descriptive epidemiologic analysis
has also shown that low vaccination coverage has
contributed to rabies epidemics (Lv et al., 2004; Wang,
2006; Li et al., 2005). Mass vaccination of the domestic
dog provides the most cost-effective and efficient strategy
for controlling canine rabies and hence transmission from
dogs to humans (Clifton, 2007).
Frequency of consumption of animal brain: Frequency
of consumption of animal brain is another factor that
might have been responsible for the continued endemicity
of rabies in Nigeria. Oral transmission of rabies could be
produced in laboratory animals like mice, guinea pigs and
hamsters using Challenge Virus Strain (CVS) and 2
strains of street virus (Madhusudana and Tripathi, 1990).
Study of virus pathway following ingestion suggested
predominant neural spread to brain and centrifugal spread
to non-neural organs like heart and kidneys. However, it
was found that virus dose required for oral infection was
relatively very high in a study by Madhusudana and
Tripathi (1990). The role of such a transmission in nature
needs to be further evaluated, keeping in view the high
dose of virus required for oral infectivity and the
frequency of consumption of brain by carnivorous
animals.
Vaccine failure: Vaccine failure is another major vaccine
and vaccination factor responsible for the continued
endemicity of rabies in Nigeria. Okoh (1982) reported 10
cases of apparent vaccine failure in Nigeria involving
modified live (low egg passage chick embryo) vaccine in
use during the study period. In their study, 4 of these
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Br. J. Dairy Sci., 1(1): 10-25, 2010
Lack of ideal cross-reactivity with modern biologicals:
Lack of ideal cross-reactivity with modern biologicals is
one other vaccine and vaccination factor responsible for
the continued endemicity of rabies in Nigeria.
Significantly, less than ideal cross-reactivity with modern
biologicals used for veterinary and public health
interventions is a major cause for concern among these
emerging viral agents [Duvenhage and Lagos bat viruses]
(Nel and Rupprecht, 2007).
cases of infection may actually have been induced by the
vaccine. In 1989, Six cases of apparent vaccination
failures in rural dogs given modified live virus, chicken
embryo origin, low egg passage, Flury-type vaccine, was
reported (Okolo, 1989). However, the most likely cause
of the vaccine failures lies in the vaccination protocols
used. According to Wu et al. (2009), any failure of
vaccination and PEP should be investigated thoroughly
and independently to trace potential errors in the protocol.
A national vaccine adverse-event reporting system should
be established to track suspected problems for safety and
efficacy. Surveillance should be heightened to monitor
efficacy of vaccines in current use in the country though
seroconversion testing after vaccination may not be
necessary in either humans or animals.
High cost of postexposure prophylaxis: Although rabies
is preventable, the high cost of postexposure prophylaxis,
compounded by the lack of education and awareness
about rabies, limits use of postexposure prophylaxis in
many developing countries such as Nigeria (Nadin-Davis
et al., 2007). This also might have contributed to the
continued endemicity of rabies in Nigeria.
Unavailability of WHO recommended RIG: This is is
another vaccine and vaccination factor responsible for the
continued endemicity of rabies in Nigeria. After severe
exposure to suspected rabid animal WHO recommends a
complete vaccine series using a potent effective vaccine
that meets WHO criteria, and administration of Rabies
Immunoglobulin (RIG). RIG is not available globally
(Yanagisawa et al., 2008) and is not marketed in Nigeria.
Lack of delivery systems and resources: Lack of
delivery systems and resources in some parts of Nigeria
especially in the rural areas is one other major factor
affecting rabies elimination and this also contributes to its
continued endemicity in Nigeria. Outbreak of rabies in
humans followed an outbreak in domestic dogs.
Increasing numbers of human rabies cases in Africa have
also been attributed to deteriorating infrastructure and
resources for rabies control. Although, the tools for
effective rabies control are available, lacking are the
delivery systems, public education campaigns and
resources to apply these technologies in the developing
world (Clifton, 2007).
Use of low potency vaccines: Use of low potency
vaccines is another vaccine and vaccination factor
responsible for the continued endemicity of rabies in
Nigeria. When post-exposure prophylaxis are most health
sector do not take time to know the sort of rabies vaccine
being injected. It is important to know the sort of rabies
vaccine injected abroad, because brain-tissue vaccines are
less effective in inducing antibody than tissue-culture
vaccines (Takayama et al., 1997).
Challenge in testing of vaccine efficacy: This is another
vaccine and vaccination factor responsible for the
continued endemicity of rabies in Nigeria. The ultimate
test of vaccine efficacy is challenge with a dose and strain
of rabies virus known to be lethal to unvaccinated
animals. However, establishing the necessary challenge
conditions, followed by carrying out the challenge
experiments themselves, would necessitate killing at least
20-30 captive wild dogs. The consensus of vets and
biologists involved in research on rabies in wild dogs and
other carnivores is that challenges would be both
unnecessary and unethical - for this reason, applications
for government licenses to carry out such experiments
would probably be unobtainable (Ginsberg and
Woodroffe, 1997).
Safety problem: The currently available modified-live
rabies virus vaccines have either safety problems or do
not induce sufficient protective immunity in particular
wildlife species. This is also is another major vaccine and
vaccination factor responsible for the continued
endemicity of rabies in Nigeria. Therefore, there is a need
for the development of new live rabies virus vaccines that
are very safe and highly effective in particular wildlife
species (Dietzschold and Schnell, 2002).
Failure to show an adequate antibody titre: Cases of
failure of vaccinated animals to show an adequate
antibody titre is another vaccine and vaccination factors
affecting rabies elimination and this also contributes to
the continued endemicity of rabies in Nigeria. In line with
study carried out in other countries, Nigeria faces with
problem of some vaccinated animals fail to show an
antibody titre adequate to meet the requirements of the 0.5
IU/ml minimal threshold level accepted by WHO/OIE
(Jakel et al., 2008).
Existence of healthy carriers: This is another factor
affecting rabies elimination and which could have also
contributed to the continued endemicity of rabies in
Nigeria. Most authors have suggested that trends in spread
of rabies may be caused by a carrier state in healthy dogs
that remains undetected (Zhang et al., 2008). The paper
by Ajayi et al. (2006) also indicates a disturbing
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vaccination factor responsible for the continued
endemicity of rabies in Nigeria. Attenuated tissue cultureadapted and natural street rabies virus (RV) strains differ
greatly in their neuroinvasiveness (Faber et al., 2004). A
study by Tomori (1980) on wild caught shrews infected
with rabies virus strains by the intramuscular,
subcutaneous and oral routes suggested a mechanical role
in the transmission of rabies. In his study, virus was
isolated only from shrews infected with street or wild
strains of rabies, but not with vaccine or fixed rabies
strains.
possibility of transmission of rabies by apparently healthy
(free of overt rabies signs) stray dogs. If their
observations are confirmed, this, in their words, "signifies
a new dimension in the epidemiology of the disease in
this environment where the high-risk practices are
prevalent (Durosinloun, 2009; Fagbo, 2009; Woolf,
2009)." What's more intriguing epidemiologically and
culturally is that the research by Ajayi et al. (2006) was
carried out in Maiduguri; the overwhelming Muslim
population in the city provides zero economic incentives
for dog meat restaurants (Durosinloun, 2009; Fagbo,
2009; Woolf, 2009). However, the dogs were slaughtered
in restaurants associated with 2 military barracks in the
city (Durosinloun, 2009; Fagbo, 2009; Woolf, 2009).
Role of rabies related viruses: The public health
significance of the rabies-related viruses was emphasized
in Nigeria where the Mokola virus was isolated from
shrews, Lagos bat virus from fruit bats and Kotonkan
were found in insects and are only distantly related to
rabies virus. This factor might have been responsible for
the continued endemicity of rabies in Nigeria.
Long incubation period: During most of the long
incubation period of rabies, the virus likely remains close
the site of viral entry. Centripetal spread to the central
nervous system and spread within the central nervous
system occur by fast axonal transport. Neuronal
dysfunction, rather than neuronal death, is responsible for
the clinical features and fatal outcome in natural rabies
(Jackson, 2003) thus, might have also contibuted to the
continued endemicity of rabies in Nigeria.
Other vaccine related problem: Other vaccine related
problems that affects rabies elimination and have also
contributed to its continued endemicity in Nigeria is the
faluire to provide subsidized post-exposure vaccination in
some part of the country. Subsidized post-exposure
vaccination is the standard response to rabies. Postexposure vaccination saves thousands of lives annually,
despite many failures when dog bite victims fail to seek
treatment soon enough, do not complete the full course of
injections, or receive fake, expired, or obsolescent
vaccines, a problem particularly prevalent in this parts of
the world, where post-exposure vaccines are not
manufactured nor made by local suppliers, and using
vaccines elsewhere long abandoned.
Inconsistent vaccination and wrong vaccination
regime: This is one of the vaccine and vaccination factor
affecting rabies elimination and this has also contributed
to its continued endemicity in Nigeria. The local increase
in the number of rabies cases and the resulting spread of
rabies in recent years has also been attributed to
inconsistent vaccination, e.g., missing complementary
distribution of baits per hand in non-flying zones
(Müller et al., 2005).
Future corrective actions: The following corrective
actions are recommended concerning mainly the weak
points that have been identified in developing countries
such as Nigeria and the preventing measures:
Inferior vaccine quality: Inferior vaccine quality is also
another vaccine and vaccination factor responsible for the
continued endemicity of rabies in Nigeria. Any potent
rabies vaccine will protect against rabies. The inferior
quality of the domestically manufactured dog vaccine has
been documented (Hu et al., 2008). According to
Wu et al. (2009), vaccine quality control and mass
production, rather than matching, are urgently needed and
most important for addressing the current rabies problem.
Communication: To provide to the Virology and
Veterinary Services all means of communication as it has
been noticed that some of them had no internet facilities,
the GSM, telephone or fax or any other mean of
communication. The radio sets once they used are all out
of order and necessitate repair and maintenance.
Vaccine shortage: Vaccine shortage is also another
vaccine and vaccination factor responsible for the
continued endemicity of rabies in Nigeria. Vaccine
shortages can result from higher-than-expected demand,
interruptions in production/supply, or a lack of resources
to purchase vaccines (Hinman et al., 2006). In developing
countries like Nigeria, the major cause of vaccine
shortages is lack of resources or political will and
commitment to purchase them.
Reporting: This point is tightly linked with the precedent
one. It is highly recommended that the field operators
(virologist, biologist, zoologist, parasitologist,
veterinarians and animal health technologists/
superintendents) should report periodically the zoosanitary events they notice and every time they feel that
something abnormal is happening. Special instructions
should be directed to the State Health and Veterinary
Services on that matter. According to the Federal
Services, the health officers, and veterinarians report
Limited number of related vaccine strains: Limited
number of related vaccine strains is another vaccine and
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surveillance system for zoonotic pathogens that gives
early warning of pathogen emergence, is closely
integrated to public health surveillance and provides
opportunities to control such pathogens before they can
affect human health, food supply, economics or
biodiversity (Chomel et al., 2007)."
monthly to the State Directorate and the Federal Offices
report quarterly to the Federal Services in Abuja; the field
technologists report if necessary and the dog owners
never report. The dog owners and hunters should be
approached by the field veterinary staff in order to obtain
their commitment in the diseases control, so they can
inform them in case of abnormality.
Preventing measures: Human PEP should be initiated on
the basis of diagnosis of biting animals. Reliable national
systemic surveillance of rabies-related human deaths and
of animal rabies prevalence is urgently needed (Wu et al.,
2009). A laboratory diagnosis-based epidemiologic
surveillance system can provide substantial information
about disease transmission and effective prevention
strategies (Wu et al., 2009). Key measures for reducing
the dispersion of emerging zoonoses such as rabies
include sustainable agricultural development, proper
education of tourists about the risks of outdoor activities,
and better control of the live animal trade (exotic pets, wet
markets, bushmeat). Public health services and clinical
practitioners (physicians, veterinarians) need to more
actively educate the public about the risks of owning
exotic pets and adopting wild animals (Chomel et al.,
2007).
Information: According to the Veterinary Services in
Nigeria, the information has been spread to the veterinary
staff, and to the administrative responsible but none of the
public or the other agents of the Ministry of Agriculture
and Natural Resources or the animal owners had been
informed. It is recommended to perform a public
information campaign through the media, in English and
local languages, taking care of the content of the
messages directed to the Public, avoiding
misunderstanding and possible panic. Papers, leaflets or
booklets on rabies epidemiology, pathogenesis and
control should be prepared and distributed to the
veterinary staff, and training sessions on clinical and post
mortem recognition should be organized. Less elaborated
leaflets and posters should be printed for distribution to
the villagers, dog breeders, and hunters and to other
concerned people and displayed in public places.
Need for detailed epidemiological studies: The need for
detailed epidemiological studies in Nigeria together with
surveillance, control, the vaccination of dogs, and
accurate data collection is emphasized. It is therefore
necessary to make the following recommendations for
effective control of this disease.
Awareness: There must be a greater public health effort
to educate clinicians and the public about proper response
to bat exposures, particularly undetectable bite exposures
(Abazeed and Cinti, 2007). Had public health authorities
been contacted to collect and test the captured bat for
rabies, there would have been no ambiguity as to the
appropriate course of action (Abazeed and Cinti, 2007).
The awareness of dog owners and hunters should be
raised, holding village level meetings. Civil
administrative authorities should also be put in state of
alert by periodical epidemiological information. An early
warning system should be implemented in every State and
at the Federal level. According to the Veterinary Services,
all the veterinary staffs are in alert but nothing have been
done on the field for the villagers. Also, to reduce risk for
emerging zoonoses, the public should be educated about
the risks associated with wildlife, bushmeat, and exotic
pet trades; and proper surveillance systems should be
implemented (Chomel et al., 2007).
C
C
C
C
C
Solid investigation and active surveillance: As no
programme of investigation at the Local Governments and
villages levels has been implemented, it is recommended
that epidemiological investigation should be carried out
by the field veterinary staff and extension personnel, in
the villages, asking a single question: "have you noticed
any abnormality on dog population”? As suggested by
Kuiken et al. (2005), it is time to form "a joint expert
working group to design and implement a global animal
C
C
C
21
Surveillance should be heightened to monitor
efficacy of vaccines in current use in the country and
measure effectiveness of control measures.
There should be public education on Rabies.
Sustained awareness, together with political and
economic commitment to animal and human rabies
control programs, particularly the vaccination of
dogs, is essential (Cohen et al., 2007).
Government policy should include stiff measures and
free mass vaccination of dogs and cats should be
carried out regularly.
Clinicians should consider rabies in the differential
diagnosis, especially in cases of fatal encephalitis and
submit appropriate specimens for rabies diagnosis
(Cohen et al., 2007).
Well equipped diagnostic laboratories and means of
identifying vaccinated animals like tagging
People at risk should have up to date pre-exposure
and post-exposure vaccination
People must avoid unfamiliar wild or domestic
animals even if they appear friendly.
People especially children must be educated to avoid
wildlife, including bats and to always keep dogs on
a leash for a walk.
Br. J. Dairy Sci., 1(1): 10-25, 2010
What next? In addition to what has been said before, it is
recommended that, in the rabid infected families, infected
persons and dogs movement should be prohibited and that
the dogs should be kept secured. For the states it is
recommended to restrict the movement and trade of dogs
coming from the rabies endemic states/countries. The
immediate emergency action on the subject by the States
Veterinary Services is required. The Nigerian Federal and
State Veterinary Services are represented in all the states
and veterinary staff can be found at least at the level of
Local Governments, covering most of the national
territory. Well trained and well equipped, they could face
the epizootics, report, inform and carry out any control
measure. The most important constraint is the lack of
funds for compensation.
Knowledge of the association of specific variants
with animal hosts has led to increasingly effective control
measures that target the hosts responsible for spreading
this disease (Slate et al., 2005). Moreover, molecular
epidemiologic approaches have enabled study of the
spread of certain rabies virus variants and their incursion
into new geographic regions. According to NadinDavis et al. (2007), adaptation of such methods in
developing countries like Nigeria would help provide
reliable data on the true extent of rabies in such countries,
provide epidemiologic data about the spread of rabies and
justify allocation of increased resources.
and transparency when managing certain health risks.
Zoonoses must be dealt with at the interface of human and
animal health by all available information (Murphy,
2008).
Public health implications of African rabies and
rabies-related lyssaviruses should be recognized by
laboratory workers, researchers, veterinarians, wildlife
personnel, gamekeepers, and pet owners. A better
understanding of the epidemiology of these viruses is vital
and can only be achieved by improved surveillance and
awareness (Sabeta et al., 2007).
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