International Journal of Animal and Veterinary Advance 3(2): 63-67, 2010
ISSN: 2041-2908
© M axwell Scientific Organization, 2010
Submitted Date: April 01, 2010
Accepted Date: April 22, 2010
Published Date: July 05, 2010
A Survey on Gastro-Intestinal Parasites of Non-Descript Dogs in and Around
Arusha Municipality, Tanzania
E.S. Swai, E.J. Kaaya, D.A. M shanga and E.W . Mbise
Veterinary Investigation Cen tre (VIC), P.O. B ox 1068 , Arusha, T anzania
Abstract: Dogs are the most comm on pet animals wo rldw ide and perform a range of cultural, social, and
econ omic functions in society. The objective of this study is to investigate, through cross-sectional survey, the
distribution, types and prevalence of gastro-intestinal parasites affecting dogs in and around Arusha
municipality, Tanzania. Faecal samples collected from 241 non-descript, apparent healthy dogs w ere processed
by sedimentation and floatations technique and then examined for protozoan oocyst and helminth eggs.
Coprological examination revealed that 59.3% of the dogs excreted helminth eggs in their faeces. Dogs
harbouring one-parasite eggs were more common (73.8%) than those harbouring two (12.4%) or three (0.4%).
The data on the distribution of the various w orm species in the positive d ogs indicate that Ancylostoma caninum
eggs were by far the most comm on (57.2% ). The other detected worm egg species and their respective
frequencies were: Toxocara canis (13.7% ), Mesostesphanus spp. (1.66%) and Taenia spp. (0.4%). Protozoan
eggs (E. canis) were detected in two samples. The prevalence of helminth eggs was higher in young dogs
(puppies) compared to adults (p<0.05). The prevalence of different species of helminths also varied in different
age groups, with Toxocara canis being higher in puppies than in adults (p = 0.005). Sex-wise prevalence of
helminths was not sign ificant (p> 0.05). The high p revalence o f gastro-intestinal helminth parasites of zo onotic
potential registered in the dog population from a highly urban area in Arusha indicates a potential risk to human
health. Increased awareness of their potential threat to human health coupled with additional research into the
zoono tic capacity of Toxocara spp. and Ancylostoma spp. is desirable.
Key w ords: Arusha, dog, endo-parasites, prevalence, Tanzania, zoonoses
INTRODUCTION
Dogs were domesticated from wolves as recently as
15000 years ago (Morey, 2006), or perhaps as early as
100000 years ago based on recent genetic fossil and DNA
evidence (Savolainen et al., 2002, Lindb ald-Toh, 20 05).
Evidence sugg ests that dogs were first dom esticated in
East Asia, possibly China, and the first people to
enter
North
America took dogs with them
(Savolainen et al., 2002). Dogs perform a range of
cultural, social, and ec onomic functions in society. Dogs
are kept as pets and companions, for hunting, as guards,
draught anim als, for food, or for commercial purposes.
Some studies also suggest that keeping pets is associated
with a higher level of self-esteem in children (Paul and
Serpell, 1996; Knobel et al., 2008 ).
W here studies have been cond ucted , parasitic
diseases, in particu lar gastro -intestinal helminths and
protozoan have been identified as the major impediment
to dog health worldwide owing to the direct and indirect
losses they cause (Smith, 1991). Most of the parasites
affect the dog sub clinically and dogs may harbour a wide
range of parasites with zoonotic potential, thus causing a
health risk to humans (Craig an d M acPherson, 2000 ). In
areas of high population density such as urban and
peri-urban, dog keeping practices may also be a risk to the
transmission of zoonoses, some of which could be of
parasitic origin (Khante et al., 2009). The major risk
factors affecting epidemiology of helminthosis and other
Gastro-Intestinal Track (GIT) parasites can be classified
broadly as parasite factors, host factors and environmental
factors (Wakelin, 1984; Harper and Penzhorn, 1999;
Thrusfield, 2005). Although dogs closely have cohabited
with humans since early civilisation, studies of dog
endoparasites in Tan zania are very limited and v ery little
information is available on the distribution, prevalence
and risk facto rs associated with parasite occurrence and
the role of parasites causing mortality in dogs in Tanzan ia
(Muhairwa et al., 2008). This inform ation is im portan t in
evaluating and recommending parasite control measures
in canine health and welfare programmes.
The current study aimed at determining the spectrum
of species and preva lence of gastro intestinal parasites,
which could be of productivity and zoonotic importance
in dogs in and around Arusha Municipality, Tanzania.
The hope was that the baseline epidemiological data
collected wou ld facilitate the developm ent of effective
interventions for controlling such infections.
Corresponding Author: Dr. E.S. Swai, Veterinary Investigation Centre (VIC), P.O. Box 1068, Arusha, Tanzania
63
Int. J. Anim. Veter. Adv., 2(3): 63-67, 2010
put into faecal pots, labelled and kept cool before
transportation to the local Veterinary investigation
laboratory where they were immediately examined or stored
at refrigerated temperature (4ºC) for a maximum of one day
before processing. The sedimentation and floatation
technique as described by Soulsby (1982) and Urquhart et
al. (1987) was used to detect the presence of stomach and
intestinal eggs (cestodes and nematodes) in the samples. The
presence of coccidia oocysts was also recorded.
MATERIALS AND METHODS
Study area: This study was conducted in and around
Arusha municipality, the second largest municipality in
Tanzania. Geographically, the mun icipality is situated at
the foot of Mount M eru (Lat 03’16S and 03’20S and
Longt 36’37 and 36’50 E) and intersect the Great North
Road from Cape Town to Cairo and is the hub of the
northern tourist circuit of T anza nia. Currently the human
population is estimated at 516,000 with a growth rate of
4% as opposed to the national of 2.8% per annum (URT,
2002). The study sites were purposively selected in
collaboration with the government livestock extension and
administration officers. The sites, com mon ly referred to
as administrative wards, were selected on the basis of
having a higher concentration of dogs and anim al health
service facility such as dog dipping tank and dog
vaccination centre. These sites included: Su ye (5
villages), Elarai (7 villages), Them i (10 villages),
Moshono (2 villages), Moivo (1 village) and Singisi
(2 villages). Elarai and Themi sites w ere within the urban
areas while Suye and Moshono were in the peri-urban and
Moivo and Singisi sites were in the rural area of the
mun icipality.
Statistical analysis: Collected data were entered, stored and
analyzed using Epi-Info version 6.04b (CDC, USA ).
Descriptive statistics were generated and presented as
tables. For the epidemiological studies, the prevalence (p)
of dog s harbouring each parasite was calculated as
p = d/n, where d is the number of dogs diagnosed as
having a given parasite at that point in time and
n = number of dogs at risk (examined) at that point in
time (Thrusfield, 2005). Associations between parasitism
and categorical (host and man agem ent) factors were
compared using chi-square tests for independence. The
level of significance was set at p<0.05.
RESULTS
Sampling procedure and data collection: In conducting
the study, a cross-sectional design in which data was
collected at a single point and time (Thrusfield, 2005) was
used. The population of study co nstituted dogs and their
own ers within Arusha Municipality and by time of
conduction this study; the number of dogs (kenneled and
feral/stray) was estimated to be 5000 (Dr. Rwegasira,
Arusha, personal communication). Breeds of dog kept
were not known to most of participating owners and
therefore they were classified as non-descript. Participants
presenting dogs (for dipping or vaccination) were required
to complete a questionnaire about their dogs. Data was
collected on the dog s’ demographic ch aracteristics (age,
gender, breed), purpose of keeping dog (pet or sec urity),
history of deworming and Rabies vaccination. The age of
the presented dogs was determined b y dentition (Bu tler,
2009) and b ody cond ition sco res w ere subjectively
estimated on two-scale level as ‘unhealthy’ or ‘health’
based on the guides published by (Marriane, 2006). Dogs
were grouped into three age categories. Do gs un der six
months of age were classed as puppies, those in range of
seven to one year were classed as juvenile and those
beyond one year were classed as adult. These age classes
were based on age of first deciduous teeth eruption,
colour and the strength of the teeth (Butler, 2009). The
study was co nducted during the period of Sep tembe r to
December 2009.
Prevalence of GIT parasite eggs and oocysts: A total of
241 dogs w ere exam ined, of which 143(59.3%) w ere
diagnosed as harbouring nematodes and cestodes eggs at
varying levels. The proportion of the dogs harbouring
hookw orm eggs (Ancylostoma caninum) was the highest
(57% ). Other gastro-intestinal parasites encountered
included Toxocara canis (13.7% ), Mesostesphanus spp
(1.6%) and cestodes/tapeworms (Taenia spp; 0.4%).
Protozoan eggs (E. canis) were detected in two samples.
Single parasite infections (n = 178; 73.8% ) were m ore
common than two or more infections (n = 31; 12.8% ).
Prevalence of GIT parasites is shown in Tab le 1. Security
reason (n = 236, 98%) was reported as the main purpose
of kee ping d ogs.
Factors associated w ith prev alence of GIT parasite
eggs infection: Significant factors influencing prevalence
of GIT parasites infection are given in Table 2. Host age
was found to be a significant factor with respect to the
prevalence of T. canis and A. caninum (p<0.05), with eggs
Table 1. Prevalence of different gastro-intestinal parasites eggs
Parasite spp
Number positive P re va le nc e( %)
A.caninum
138
57.3
T. can is
33
13.7
Mesostesphanus spp
4
1.6
Taenia spp
1
0.4
E.ca nis
2
0.8
A.caninum + Tox ocar a can is
24
10.8
A.caninum + E. ca nis
2
0.8
A.caninum + mesostephanus spp
3
1.2
A.caninum + Taenia spp
1
0.4
A.caninum + T.can is + mesostephanus spp
1
0.4
Sampling and parasitologic techniques: Faecal samples
(fresh stool) were collected per-rectum using plastic gloves,
64
Int. J. Anim. Veter. Adv., 2(3): 63-67, 2010
Table 2: Proportion of each category investigated and the associated prevalence of parasite
Va riable
No. of examined
%
P re va le nc e (% )
Age category
Puppies
54
22 .4
13(24)
Juv enile
32
13 .3
5(15.6)
Ad ult
155
64 .3
6(3 .8
Sex
Females
73
30 .3
10(13.7)
Males
168
69 .3
14(8.3)
Source
Homeb red
Bro ugh t- in
Healthy status
Healthy
Unhealthy
Breeds
Local
Cross
240
1
235
6
229
12
History of rabies vaccination
Yes
121
No
120
History of deworming
Yes
No
98
143
99 .6
0.4
97 .5
2.5
95
5
50 .8
49 .2
40 .8
59 .2
P2
p-value
14 .0
0.005
1.02
0.599
0.00
0.900
0.54
0.470
0.35
0.840
0.36
0.020
0.70
0.431
24(10)
0(0)
23(9.7)
1(16.6)
23(10.04)
1(8.3)
7(5.7)
17(14.1)
8(8.1)
16(11.1)
been detected more frequently in puppies (<6 months of
age) than juvenile and adult dogs. There was no
significant difference in the prevalence of gastro intestinal
parasites between male (8.3%) and female (13.7%) dogs
(p>0.05). There were no significant differences in the
prevalence of parasite infection between local and
crossbred dogs (10.04% vs. 8.3%; p>0.05 ). Health status,
source, history of last anthelmintic treatment (less or more
than 3 mo nths prior to sam pling) w ere no t significantly
associated with prevalence of parasite infection (p =
0.431). Surprisingly, dogs vaccinated against rabies in the
last one year prior to the study survey were significantly
associated with lower prevalence of GIT parasite infection
(p = 0.020 6).
animal health management programmes or non-adoption
of the modern anima l health care programmes by dog
owners.
Mixed parasitism involving two or mo re helm inth
genera was com mon in the present study and is in
agreements with earlier reports (Akao et al., 2003;
Sowemimo and Asaolu, 2008; Katagiri and OliveiraSequeira, 2008). A. caninum and T. can is were the most
incriminated helminths in dogs. Other helminth/oocyst
genera detected, though at a low frequencies included
Mesostesphanus spp and Eim eria ca nis. This is the first
time that the protozoan E. can is has been reported
in northern Tan zania. The prev alence of 57.3% of
A. caninum in this stud y is higher than the prevalence of
41% obtained in Nigeria and Kenya (Ugochukwu and
Ejimadu, 1985; Kagira and Kanyari, 2000).The higher
prevalence obtained in this result than those obtained in
Kenya, and other relevant areas similar to those found in
Tanzania could be du e to the nature of the environme nt,
poor levels of hygien e and overc rowding e specially in
communities that are socio-economically disadvantaged
together with the lack of veterinary attention (Craig and
MacPherson, 2000). Over crowding enhances high
potential of environmental contamination with the
parasite-laden faeces, leading to an increased rate of
transmission of helm inth parasites (K irkpatrick, 1988;
Rebecca et al., 2002; Ugbomoiko et al., 2008 ).
Consistent to other studies, pup pies were associated
with high prevalence of helminth infection particularly for
A. caninum (Kagira an d Kanyari, 2000). Puppies are
DISCUSSION
The microscop ic fecal examination showed that
helminthosis was an important health disease in the study
area. This finding is in agree ment w ith the results of
other researchers, that helminthosis is one of the m ain
problems in dogs w orldwide (Minn aar et al., 2002;
Akao et al., 2003; Muhairwa et al., 2008;
Davoust et al., 2008).
The overall prevalence of 59.3% of GIT parasite
eggs/oocyst in the dogs in this study sho ws that there
were frequent infections of our indigenous dog s with
different species of helminthes and protozoans. The
relatively high level of parasitism recorded in this study
is probably related to th e lack of improvement in our
65
Int. J. Anim. Veter. Adv., 2(3): 63-67, 2010
usua lly born with or acqu ire asca rid infection early in life
through trans-mam mary and trans-placental transmission
(Herd,
1979 ;
Ugochukwu and Ejimadu, 1985;
Hendrix et al., 1996).
Mo st of the dogs exam ined appeared to be in fairly
good health cond ition, but yielded different types of
helminth eggs during examinations. A good number of
dog owners/keepers in the stud y area perceive helminth
infection as a pre determined coincidental manifestation,
which no body cou ld do anythin g to prevent.
Although sex did not emerge as a significant factor in
this study, females dogs w ere more infected w ith helm inth
parasites than their male counterparts. This m ay be due to
the physiological peculiarities of the female dogs, which
usua lly constitute stress factors thu s reducing their
immunity to infections (W akelin, 1984 ).
The significance of this survey is that persistent
infections of dogs by helminth like Toxocara canis in
addition to its deleterious effects o n dog’s causes public
health hazards. This helminth produces a condition known
as visceral larva migrans in children and ocular migrans
in adult human beings (Oladele et al., 2006;
Gavignet et al., 2008). Although the seriousness of
infection of Toxocara canis depe nds o n the site of parasite
migration, the aberrant larvae occasionally invade the
central nervous system. Neurological problems, such as
epilepsy, neuropsychologic deficits, and ataxia have been
observed clinically in humans. In the case of ocular larval
migrans, vision loss and perm anen t blindness m ay result
(Akao et al., 2003 ; Nithiuthai et al., 2004).
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helminths infections are prevalent and locally wide
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ACKNOWLEDGMENT
W e thank dog ow ners/guardians for their
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