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Chinchilla x New Zealand white cross breed rabbits (N=24)were challenged with strain of T. congolense. The infections were characterized by intermittent pyrexia, undulating parasitaemia, anorexia and emaciation. The major haematological changes observed were anaemia that was macrocytic normochromic at the first week of the infection and later became normochromic normocytic till the end of the experiment and leucopaenia that is characterized by neutropaenia, eosinopaenia and lymphocytosis. Plasma biochemical changes include hypoglycaemia, elevated total protein and plasma cholesterol. There were significant (p<0.05) elevation of Alkaline phospatase (ALP), Aspertate aminotransferase (AST), total bilirubin and fluctuating changes in the levels of plasma Alanine aminotransferase (ALT) and urea. Gross pathological changes include congested and oedematous lungs, mucoid enteritis, hepatomegaly and splenomegaly. Histopathological changes include mild congestion of the splenic pulp, mild venous congestion of the liver, pulmonary congestion, acute bronchopneumonia, severe emphysema of the lung, and focal centrilobular necrosis and periportal mononuclear cell aggregation in the kidney. This study shed light on the dynamics of haematological alteration and distortion of architectural frame work of various tissues of rabbits experimentally infected with T. congolense and suggested that rabbit is susceptible to T. congolense and could act as reservoir for trypanosomosis of ruminants and domesticated dogs used for hunting.

The DQB1 locus is located in the major histocompatibility complex (MHC) class II region and involved in immune response. We identified 20 polymorphic sites in a 228 bp fragment of exon 2, one of the most critical regions of the MHC DQB1 gene, in 60 Nigerian goats. Four sites are located in the peptide binding region, and 10 amino acid substitutions are peculiar to Nigerian goats, compared with published sequences. A significantly higher ratio of nonsynonymous/synonymous substitutions (dN/dS) suggests that allelic sequence evolution is driven by balancing selection (P < 0.01). In silico functional analysis using PANTHER predicted that substitution P56R, with a subPSEC score of -4.00629 (Pdeleterious = 0.73229), is harmful to protein function. The phylogenetic tree from consensus sequences placed the two northern breeds closer to each other than either was to the southern goats. This first report of sequence diversity at the DQB1 locus for any African goat breed may be useful in the search for disease-resistant genotypes.

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Aqueous extracts of 5 medicinal plants comprising of the root bark of Morinda morindiodes and leaves of Tithonia diversifolia, Lippia multiflora, Ocimum gratissimum and Acalypha wilkesiana were investigated for antitrypanosomal activities in albino rats infected with Trypanosoma brucei brucei. The plant extracts at 400mg/kg body weight (of rats) were administered once daily for 7 days in an established infection of 5 x 10 6 parasitaemia before starting treatment. There was significant reduction in parasitaemia (P< 0.05) on the 3 rd day of treatment in rats treated with Morinda morindiodes, Tithonia diversifolia and Acalypha wilkesiana but parasitaemia later increased till survival time. Morinda morindiodes , a plant well known for its potents antimalarial effect, has it root bark extracts exhibiting the highest value of mean survival time (12.6+0.7) days this study. The result may probably suggest reduction in parasite virulence by Morinda morindiodes root bark extract.

Trypanosomosis remains a major challenge to livestock production in much of tropical Sub-Saharan Africa, while diagnosis and treatment still depend on inefficient parasitological techniques. Endemic infections depend on animal reservoirs with subclinical parasitemia. We report molecular diagnosis of subclinical Trypanosoma vivax (T. vivax) infection using polymerase chain reaction (PCR) for the first time in Nigerian goats and associate parasite presence with gross physiological traits and serum metabolites in extensively managed Nigerian goats. PCR was used to amplify a 400 bp DNA fragment of the parasite genome in 205 goats across three geographical zones of the country. Results showed a high subclinical infection rate (SCIR) of 71.7% in the total goats examined. Overall SCIRs of 71%, 75.9% and 55.6% were recorded in West African Dwarf, Red Sokoto and Sahel goats respectively, while geographical SCIRs were 71.2% (Southwest), 75% (Northwest) and 70% (Northeast). T. vivax presence had significant (P < 0.05) effect on respiratory rate and is associated with higher creatinine levels in sera. Logistic regression analyses with Hosmer-Lemeshow goodness-of-fit showed that respiratory rate is the most important predictive trait for the presence of T. vivax infection (P < 0.05). Goats appear to be a viable reservoir for T. vivax infection of other livestock. Molecular diagnosis of subclinical trypanosomosis using PCR could be useful for large scale epidemiological studies, early diagnosis of subclinical infection and treatment of the disease in extensively managed tropical goats.

Canine ehrlichiosis is an important tick-borne rickettsial disease mainly caused by Ehrlichia canis. This study aimed to detect and characterise E. canis in dogs in Abeokuta, Nigeria by microscopy and nested PCR. Blood samples were collected from 205 dogs, thin smears were made, field-stained, and DNA was extracted from the blood samples. A partial region of the 16S rRNA gene was amplified by polymerase chain reaction (PCR) and sequenced unidirectionally. Ehrlichial morulae were detected in three dogs (1.5%). The PCR test revealed that 47 dogs (22.9%) were positive for E. canis. The lengths of the sequences obtained range from 374 bp to 376 bp with an average G-C content of 37% and 98-99% homology with the reference sequences in GenBank. The aligned autochthonous sequences were less polymorphic. The phylogenetic analysis separated sequences reported previously in Nigeria from the autochthonous sequences. The present work shows that the strain of E. canis detected in the study area is genetically different from those reported in the northern part of Nigeria and more closely related to sequences from Brazil and India.

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