Fasciola hepatica and Fasciola gigantica habitually co-exist as parasites of cattle (Bos taurus) and water
buffalo (Bubalus bubalis), and despite variation in their morphometry, their species status is suspicious.
Liver flukes isolated from cattle and water buffalo were initially sorted as F. gigantica or F. hepatica, and
crude proteins were extracted and subjected to SDS-PAGE. Cattle had the preponderance of F. gigantica,
while F. hepatica was the dominant species in water buffaloes. Co-existing cattle and bubaline fasciolids
revealed similar protein profile suggestive of a close genetic relationship. The distinct heavy bands shared
by co-existing bubaline F. hepatica and F. gigantica relative to those detected in cattle fasciolids suggests a
host species-related influence. Between cattle and bubaline F. hepatica, six bands (220kDa, 150kDa,
115kDa, 67kDa, 34-37kDa, 30kDa) were bubaline-specific; between cattle and bubaline F. gigantica, four
bands (212kDa, 150kDa, 70kDa, 30kDa) were bubaline-specific, while only three bands were shared
(150kDa, 67-70kDa, 30kDa) by bubaline F. hepatica and F. gigantica. Current molecular findings
represent the first in the country, where fascioliasia is prevalent. Confirmation of these results entails
protein profiling of extracts of freshly-collected individual worms alongside extracts of infected and
non-infected liver tissue samples, to mark out host-derived proteins. Its surveillance in susceptible host
species in farms around the country, jointly with analysis of morphological and morphometric data of
co-existing fasciolid species is highly recommended.
Oligomannose-coated liposome (OML)-based vaccines have been reported to induce Th1-based immunity
against entrapped antigens in immunized animals and to show protective effects against several protozoal
diseases. In the present study, we produced a recombinant Babesia rodhaini ribosomal phosphoprotein P0
(rBrP0) that showed immunological cross reactivity with another rodent Babesia parasite, B. microti. We
evaluated the efficacy of vaccination with OML-entrapped rBrP0 on B. rodhaini and B. microti infections in
mice. Prior immunization with the OML-based rBrP0 vaccine, or with a Freund’s adjuvant-based rBrP0
vaccine, failed to demonstrate any protective effect against lethal infection with B. rodhaini, but the
OML-based vaccine did induce protective immunity against B. microti infection, based on a reduction in
peak parasitemia levels and prompt clearance of the parasite, compared with control mice. OML might be an
effective adjuvant for future vaccines aimed at the control of severe domestic babesioses.
Aflatoxins are known to alter the pathogenesis of many infectious diseases, but such effects have not been
evaluated in trypanosome infections. The aim of the present work was to assess the effects of aflatoxin B1 on
the pathogenesis of Trypanosoma brucei rhodesiense infection using a murine model. Mice fed on 0.50 mg/kg
aflatoxin b. wt. were infected with T. b. rhodesiense and compared to trypanosome infected and uninfected
aflatoxin-fed controls. The clinical and pathological changes were determined and the quantitative data
statistically analysed using standard methods. The results showed that infected aflatoxin-fed mice had
pronounced dyspnoea, significantly (P<0.05) reduced survival, extreme emaciation, pronounced macrocytic
normochromic anaemia characterized by significantly (P<0.05) reduced red cell count, packed cell volume,
haemoglobin levels and significantly (P<0.05) increased mean corpuscular volume compared to controls.
Grossly, there were pronounced hydrothorax and ascites while histologically, haemorrhages, thrombosis,
embolism, massive peri-vascular inflammatory cell infiltration were observed in the infected aflatoxin-fed mice.
Severe anaemia, liver damage, nephritis and pancarditis were the major complicating factors which could have
caused reduced host survival. It was concluded that aflatoxicosis aggravated the pathogenesis of T. b.
rhodesiense infection in mice, and should therefore be taken into consideration during trypanosomosis control
Recently, Babesia bovis genome project identified a novel gene, which is homologous to the gene encoding
sporozoite P36 antigen in Plasmodium parasites. In the present study, we isolated the P36 homologous gene
from the genomic DNA of B. bovis and designated it as the BvP36 gene. The sequence of the BvP36 gene
was identical to that reported previously. This gene was expressed in an Escherichia coli system to produce a
recombinant protein (rBvP36). The rBvP36 protein was produced as a highly soluble form in E. coli and was
detected by western blot analyses of sera collected from cattle experimentally infected with B. bovis and B.
bigemina merozoites. In indirect immunofluorescence tests, sera collected from mice immunized with
rBvP36 showed strong reactions to both B. bovis and B. bigemina merozoites. Our results indicate that the
BvP36 antigen is expressed at least in the asexual merozoite stage of B. bovis and suggest that B. bigemina
merozoite carries an antigen similar to BvP36.
Apicidin, a histone deacetylase inhibitor, has a broad spectrum of anti-protozoal activities against
apicomplexan parasites. In the present study, we evaluated the inhibitory effect of apicidin on the asexual
growth of bovine Babesia parasites (B. bovis and B. bigemina) in vitro, as well as on the in vivo growth of B.
microti in mice. The growth of B. bovis and B. bigemina was significantly inhibited in the presence of 3
ng/ml apicidin. Complete inhibition of B. bovis and B. bigemina growth was achieved on the fourth and third
days, respectively, after treatment with 729 ng/ml apicidin. These parasites failed to grow again even when
drug-free medium was substituted. The 50% inhibitory concentrations of apicidin against B. bovis and B.
bigemina were determined as 7.1 and 20.7 ng/ml, respectively, in in vitro cultures with serum-containing
M199 medium. Severe morphological signs of damage, such as pyknotic and degenerative changes, were
observed in the treated parasites. Apicidin 2 mg/kg caused significant inhibition of B. microti growth and
altered the parasitemia dynamics in mice, compared with untreated control mice. Apicidin could be an
effective chemotherapeutic agent for the treatment of bovine and human babesioses.
Clinical and pathological characterisation of blood stream (BSF) and cerebrospinal fluid (CSF) forms of
Trypanosoma brucei rhodesiense trypanosome isolated from a sleeping sickness patient were investigated in
rabbits. The study aimed at investigating whether there is any significant difference in clinical and
pathological presentation in rabbits infected by the two forms of trypanosomes. Each form of parasite was
inoculated into five rabbits at 104 trypanosomes/ml while five rabbits were used as un-infected controls.
Parasitaemia development, body temperature, packed cell volume (PCV), body weight, food and water
intake, heartbeat and respiration were monitored daily for 30 days post infection when the experiment was
terminated. Pathological changes were evaluated following euthanasia. All the infected rabbits became
parasitaemic 6 days post infection (dpi) and the parasitaemia levels were significantly higher (p=0.01) for the
BSF than the CSF infected rabbits. No significant difference was observed in heartbeat, respiration, food and
water intake as well as PCV. However, CSF infected rabbits had a significantly (p=0.01) higher body
temperature and weights than BSF infected rabbits. There was no major difference in the clinical
manifestation of the disease caused by the two forms of parasite. However, temporary paralysis was observed
around the left side of the neck in one rabbit infected with CSF trypanosomes whereas mucoid stool with the
presence of amoeba cysts were observed in the rabbits infected with the BSF trypanosomes. The spleen
weights of CSF infected rabbits was heavier (3.59 ± 1.13 grams) than the BSF infected rabbits (2.92± 0.78
grams). The proportions of monocytes were significantly higher (p<0.05) in the CSF infected rabbits while
neutrophils proportions were significantly higher (p<0.05) in the BSF infected rabbits. The rest of the
haematological changes were not significantly different. Results from this study demonstrate that BSF
trypanosomes appeared relatively more virulent than the CSF trypanosomes. It would be important to carry
out similar studies using a higher number of both BSF and CSF trypanosomes isolated from the same patient
and different patients to authenticate this observation.
A fragment of a novel gene, designated as the BboP67 gene, of Babesia bovis, which had been recently
reported as a homolog of the gene encoding a sporozoite-specific P67 antigen of Theileria parva, was
isolated from the genomic DNA of B. bovis and expressed as a recombinant (rBboP67) in E. coli. The
antigenicity of rBboP67 was evaluated using 102 and 68 field serum samples collected from cattle in Ghana
and Mongolia, respectively. All of the B. bovis- and B. bigemina-infected sera, which had been identified by
the species-specific antigens, rRAP-1/CTs, for B. bovis and B. bigemina in the standard ELISA, positively
reacted with the rBboP67 in ELISA. While B. bovis-infected field serum samples recognized the rBboP67 in
Western blot analysis, sera collected from the experimentally infected cattle with B. bovis merozoites failed
to react to it. IFAT analysis conducted with polyclonal antisera collected from the immunized mice with
rBboP67 did not show any positive reaction to the B. bovis merozoites. These results indicate that the p67
homolog is not expressed in merozoite stage but is likely expressed in sporozoites; they also suggest that the
antigen might be relatively conserved among different isolates of B. bovis and, at least, several epitopes of
the antigens might be shared between B. bovis and B. bigemina sporozoites.