ISRAEL JOURNAL OF
VETERINARY MEDICINE
Vol. 59 (4)
2003
PATHOGENICITY OF MYCOPLASMA
CAPRICOLUM SUBSPECIES CAPRICOLUM FOR
CATTLE IMMUNOSUPPRESSED WITH
TRYPANOSOMA CONGOLENSE.
Ajuwape A. T. P.1, Adetosoye A. I.1, Ikheloa J. O. 1, Alaka O. O. 2,
Taiwo V. O. 2, Talabi O. A.3, Otesile E. B.3, and Ojo M. O. 1.
1. Department of Veterinary Microbiology and Parasitology
2. Department of Veterinary Pathology,
3. Department of Veterinary Medicine
University of Ibadan, Nigeria.
Abstract
The pathogenicity of Mycoplasma capricolum subspecies capricolum
in Red Bororo (RB) bull calves was investigated. Two calves infected
with 4.21 x 106 cells of Trypanosoma congolense and later inoculated
endobronchially with 1.6 x 109 CFU / ml of M. capricolum subspecies
capricolum (Tc/Mcc) died 38.0±1.4 days post infection (pi) presenting
fibrinous intersititial pneumonia and severe lymphoid depletion in spleen
and lymph nodes. While another set of two calves were infected with
Trypanosoma congolense only. The mean PCV values (mPCV) of each of
the four Tc-infected RB calves (21.7±2.4%, 25.5±2.5%, 23.3±3.9% and
23.3±2.4%) were significantly (P<0.05) lower than that of the control
(31.1±1.7%). The mean rectal temperature (mRT) of each of the four
calves (39.6±0.8oC, 40.0±0.5oC, 37.9±0.5oC and 38.1±0.2oC) with Tc
and Mcc or Tc infections was significantly (P<0.05) higher than that of
the control (38.2±0.5oC). In these experimental infections, necropsy
examinations revealed oedema, congestion, consolidation and marbling of
the lungs. Histopathological changes observed were inter-alia thickening
of the interlobular septae by fibrin and showers of lymphocytes. The
spleen showed lymphoid necrosis and haemosiderosis in the red pulp.
Mycoplasma capricolum subspecies capricolum was recovered from the
lungs, lymph nodes, kidneys, spleen and liver of the dead calves. The
Trypanosoma congolense infection induced a state of
immunosuppression. In Africa, where cattle are herded along with sheep
and goats, this study revealed that Mycoplasma capricolum subsp.
capricolum can indeed cause CBPP-like lesions that may be
indistinguishable from CBPP caused by bovine mycoplasmas. It is
therefore suggested that thorough laboratory investigation should be
carried out along with post mortem examination of suspected CBPP cases
to identify the specific Mycoplasma species involved. Efforts should be
made to immunize cattle, sheep and goats against M. capricolum subsp.
capricolum.
Introduction
Mycoplasma capricolum subspecies capricolum has been reported
as an agent of pneumonia in goats (1, 2) causing high mortality (1) and
consequent severe economic losses and shortage of animal protein. This
organism has also been incriminated as causative agent of sheep
pneumonia with high mortality (2). However, this pathogen has been
isolated from the external ears of normal goats (3, 4). The population of
goats, sheep and cattle in the northern states of Nigeria was given as
34.45 million, 22.2 million and 13.99 million respectively (5). While,
recent information suggests that rinderpest is on the verge of being
eradicated in Nigeria, the incidence of CBPP is on the increase (6).
Although cattle are vaccinated annually against CBPP in Nigeria,
sporadic outbreaks are still observed, especially in some Northern States
of Nigeria such as Kaduna, Borno, Sokoto, Bauchi, Kano and Kastina (7,
8, 9). It is relevant to note that in those states, ruminants are raised in
close association, co-mingling. This type of animal husbandry system
enhances the risk of transmission of disease pathogens between
different species, as well as intra- species transmission. This may explain
why M. capricolum subsp. capricolum may be harvested from bovines
(10).
Materials and Methods
Mycoplasma organism
Mycoplasma capricolum subspecies capricolum recovered from pneumonic
lungs of goats slaughtered in Northern Nigeria was used for this study(11). The
biochemical characteristics of the isolate viz sensitivity to digitonin,
fermentation of glucose, hydrolysis of arginine, reduction of tetrazolium
chloride in liquid media, digestion of serum, negative phosphatase activity, and
no formation of film and spots indicated that the isolate is Mycoplasma
capricolum subspecies capricolum Calif. Kid (12). Also the isolate was
identified serologically to be Mycoplasma capricolum subspecies capricolum.
The National Institute of Trypanosomiasis Research, Vom, Plateau State,
Nigeria supplied the Trypanosoma congolense used in this study. The T.
congolense was passaged in mice before inoculation. When the parasitaemia was
high (4.21 x 106/CFU/ml), the trypanosomes were harvested.
Animals: Five Red Bororo bull calves, about 12 months old were purchased
from a farm in Sokoto, Sokoto State, Nigeria where there was no history of
contagious bovine pleuropneumonia, brucellosis and rinderpest. The calves were
transported to Ibadanand housed at the large animal facilities of the Veterinary
Teaching Hospital, University of Ibadan. The animals were kept in 3.96m x
3.96m concrete pens and treated with diaminazene aceturate (Berenil®)
intramuscularly at a dose rate of 5.0mg/10kg body weight (BW) against
haemoparasites (Trypanosoma and Babesia) and dewormed orally with
tetramizole (Nilverm® ICI Pharmaceutical, UK) at a dose rate of 66mg/kg BW.
They were allowed to acclimatize for 4 weeks, after which the animals were
confirmed negative for the presence of haemoparasites especially Babesia,
Trypanosoma and Anasplasma species and intestinal helminthes by standard
methods (13,14). With the aid of sterile swabs, clinical samples were obtained
from the eyes, ears, nostrils and rectum of each calf and examined
microbiologically for Mycoplasma (15, 16) and other bacteria (17).
Pathogenicity test: Four Red Bororo bull calves were respectively inoculated
with 4.21 x 106 trypanosome cells per milliliter of T. congolense intravenously
through the jugular vein. Blood samples were collected from each bull every
three days through the jugular vein to determine the level of parasitaemia. Also
the PCV of each bull calf was determined by standard methods (14). The
temperature and clinical signs of each calf were observed daily.
Inoculation of Mycoplasma capricolum subspecies capricolum: When the
PCV of each bull calf was 20% or slightly below, two of the bull calves were
endobronchially inoculated as previously described elsewhere (18) with 10 ml of
1.6 x 109 CFU/ml of Mycoplasma capricolum subspecies capricolum,
propagated in medium N (15, 16) after incubation at 37o C for 4 days. Another,
group of two bull calves inoculated intravenously with 4.21 x 106 T. congolense
/ ml. served as controls for Trypanosome-infected calves. The PCV values of the
calves were monitored till the PCV values fell to 20% and below at which point
they were treated with diaminazene aceturate (Berenil) intramuscularly, at a
dose - of 5.0mg/10kg body weight (BW). The remaining calf was inoculated
endobronchially with sterile medium N served as negative control.
Results
The 2 Red Bororo bull calves infected with 4.21 x 106 T. congolense cells
/ ml. and later followed by endobronchial inoculation with 1.6 x 109 CFU / ml of
Mycoplasma capricolum subspecies capricolum when their PCV values dropped
to 20% respectively, died 36.0±2.1 days post infection (pi) The mean PCV
values of each of the four calves (RB191, RB192; RB193 and RB194)
inoculated with T. congolense were significantly lower (P<0.05) than the value
for RB196 which was not infected with T. congolense. The PCV values of
calves (RB193 and RB194) that were infected with T. congolense and were
subsequently treated with Berenil® did not return fully to the original values up
to 14 days pi despite the fact that no parasite was found in the blood sample
(Table 1). This agrees with the observation of Dargie et al. (1979) that the PCV
shows little tendency to recover even when parasites are undetectable for up to
four months post-infection with trypanosome. However, the mean rectal
temperatures of RB191 and RB192 respectively was significantly higher than
the control calf RB196 as well as rb193 and rb194 which were infected with T.
congolense and were subsuqeuntly treated with Berenil (Table 1).
At necropsy the calves showed pale oedematous pneumonic lungs, grossly
characterized by consolidation and marbling especially at the diaphragmatic
lobes. Also the mediastinal lymph nodes were haemorrhagic and haemorrhages
were seen in the heart. Furthermore, foci of necrosis were found in the kidneys
and the synovial fluid from the joints of these animals possessed amber
coloration. However, the liver and spleen of the respective calves looked normal
grossly.
The histopathological changes included congestion and oedema of the
lungs (Fig. 1). Histopathological sections of the lungs showed thickening of the
interlobular septae by fibrin and showers of mononuclear lymphocytes. The
spleen showed marked lymphoid necrosis and haemosiderosis in the red pulp.
There was extensive lymphoid depletion in the peri-arteriolar lymphoid sheaths
(PALS) (Fig. 2). Also the lymph nodes showed severe haemosiderosis,
erythrophagocytosis and lymphoid depletion. The kidneys had multifocal
interstitial lymphocytic infiltrations (Fig. 3a and 3b). Mycoplasma capricolum
subspecies capricolum was recovered from the lungs, liver, lymph nodes, spleen
and kidneys, using standard methods (15, 16).
The calves given 4.21 x 106 T. congolense / ml. and treated with
diaminzene aceturate (Berenil), intramuscularly recovered completely around 7
days post-treatment, and the PCV values by that time had risen from 20% to
25%. However, the calf endobronchially inoculated with 10ml sterile medium N
showed no clinical signs of disease and the body temperature was 38.2±0.5oC,
and no Mycoplasma capricolum subspecies capricolum was recovered from this
animal.
Figure 1: A section of the lung showing pulmonary congestion and oedema.
Figure 2: A section of the spleen with lymphoid necrosis and depletion of the
peri-arteriolar lymphoid sheath (PALS).
Figure: 3a and 3b: Kidney sections with multifocal lymphocytic infiltration
in the interstitium.
Discussion
From this investigation, it was observed that when Mycoplasma
capricolum subspecies capricolum was given concurrently with T. congolense
which served as an immunosuppressor, classical CBPP lesions were observed.
Similar pulmonary lesions have previously been recorded in Mycoplasma
capricolum subspecies capricolum infected kids, sheep and pigs (1). The mean
PCV values of each of the four calves (RB191, RB192; RB193 and RB194)
inoculated with 4.21 x 106 of T. congolense were significantly lower (P<0.05)
than the value for RB195 which was not infected with T. congolense. These
findings support the earlier reports that this parameter and other erythrocytic
parameters are depressed during trypanosomosis (19, 20, 21, 22). However, the
mean rectal temperatures of RB191 and RB192 was significantly higher than the
control calf RB195 as well as RB193 and RB194 which were infected with T.
congolense and were subsuqeuntly treated with Berenil (Table 1). There is a
dearth of information on Mycoplasma capricolum subspecies capricolum
pathogenicity in cattle under natural conditions. That the two calves in the group
exposed to the dual infection died is of epizootiological importance. This is
because in this investigation, under a state of immunosuppression coupled with
anaemia produced by T. congolense in the infected calves, thereby making it
impossible for the immune system of the calves to fight the invading
Mycoplasma capricolum subspecies capricolum. This organism caused marbling
and consolidation of the left diaphragmatic lobe of the lungs which were also
oedematous.
Similar lesions resembling classical contagious bovine pleuropneumonia
have been produced following establishmentof the above dual infections, T.
vivax and Mycoplasma mycoides subspecies mycoides LC, in exotic calves
endobronchially inoculated with Ib9, a strain of Mycoplasma mycoides
subspecies mycoides (23). The results of this investigation made it clear that in
areas where there is no adequate control programme in place for
trypanosomosis, the prevalent Trypanosome species, especially T. vivax and T.
congolense which are mostly responsible for African trypanosomosis, might
continue to induce immunosuppression in ruminants. This immunosuppressive
state might make the ruminants vulnerable and succumb to caprine strains of
Mycoplasma species. Efforts should be made to prophylactically treat calves
with trypanocidal drugs to control trypanosomosis and thereby prevent incidence
of CBPP which might occur should caprine strain of Mycoplasma species infect
cattle in Trypanosome endemic areas. The diagnosis of CBPP at the abattoirs
should be backed up by good laboratory diagnosis including DNA probes (24)
using PCR to detect Mycoplasma mycoides subspecies mycoides SC (25, 26) as
an adjunct to the isolation and identification of Mycoplasma species, the
traditional method of definitive diagnosis (15, 16, 27).
LINKS TO OTHER ARTICLES IN THIS ISSUE
References
1. Damassa, A. J.; Brooks, D. L.; Adler, H. E. and Watt, D. E.: Caprine
mycoplasmosis: Acute Pulmonary disease in newborn kids given Mycoplasma
capricolum orally. Aust. Vet J., 60: 125-126, 1983.
2. Damassa, A. J.; Brooks, D. L. and Cordy, D. R: Pneumonic lesions in young
goats induced by Mycoplasma capricolum. Reply Aust. Vet. J., 61: 202, 1984.
3. Cordy, D. R.; Alder, H. E. and Yamamoto, R.: A pathogenic
pleuropneumonia-like organism from goats. Cornel Vet. 48: 24-30, 1955.
4. Cordy, D. R. and Adler, H. E.: Patterns of reaction in infection with a virulent
form of pleuropneumonia-like organism from goats. Ann. N. Y. Acad. Sci. 79:
86-695, 1960.
5. Adedipe, N.O ; Kakshi, .S.; Odegbaro O.A and Aliu, A.: Evolving the
Nigerian Agricultural Research Strategy plan Agro ecological inputs. N.A.R.P.
pp. 486, 1994.
6. Aliyu, M.M, Obi, T.U., Oladosu, L.A., Egwu, G.O. and Ameh, J.A.: The use
of competitive enzyme linked immunosorbent assay in combination with
abattoir survey for CBPP surveillance in Nigeria. Trop. Vet. 21(2): 35-41, 2003.
7. Muhammed, L.U.: Economic evaluation of CBPP in Nigeria. Proceedings of
the Annual Nigeria Veterinary Medical Association (N.V.M.A) Conference, Jos,
Nov. 24 - 26. pp. 2-4. 1986.
8. Nawathe, D.R.: Resurgence of contagious bovine pleuropneumonia in
Nigeria. Revue Scientifique et Technique Office International des Epizooties 11:
779-804, 1992.
9. Ameh, J.A., Nawathe, D.R and Fam, M.I.: Retrospective microbiological and
serological studies of contagious bovine pleuropneumonia (CBPP) in Nigeria.
Trop. Vet. 16: 69 - 71, 1998.
10. Breard, A. and Poumarat, F.: Isolement de Mycoplasma capricolum à partir
d`un sperme de taureau. Revue Elev. Med.vet.Pays trop. 41: 149-150, 1988.
11. Ikheloa, J, O.; Ajuwape, A. T. P. and Adetosoye, A. I.: Biochemical
characterization and serological identification of mycoplasmas isolated from
pneumonic lungs of goats slaughtered in abattoirs in northern Nigeria. Small
Rumin. Res. In-press, 2003.
12. Rurangirwa, F. R.: Mycoplasmas of small ruminants. In: Pan-African
symposium on Mycoplasmas and associated diseases of animals, man and
plants. Faculty of Veterinary Science, University of Zimbabwe. September 5-11.
pp. 93-99, 1993.
13. Soulsby, E. J. L.: Arthropods and protozoa of domesticated animals 7th
edition. Bailiere Tindal E.L.B.S. London. p. 793, 1982.
1.