Effect of temperature on the sodium sulphite precipitation test for assessment of goat serum immunoglobulin.

Total serum immunoglobulin concentrations of apparently normal indigenous goats were estimated by a sodium sulphite precipitation test which utilized 3 concentrations of the salt (i.e. 14%, 16%, 18%). A total of 210 goat serum samples comprising five phenotypically different breeds were examined. Immunoglobulin precipitation was greatly influenced by the incubation temperature. Using different concentrations of the sodium sulphite salt solution, serum samples incubated at either 4 degrees C or 38 degrees C consistently gave clear and rapid precipitation reaction in all samples with immunoglobulin concentrations of over 15 mg/ml. Tests carried out at normal tropical room temperature (28 degrees-30 degrees C) gave inconsistent results and only 52% gave clear precipitation. Neither breed nor sex had any statistically significant effect on either the precipitation rate or the immunoglobulin values (P less than 0.05). It was concluded that this test if performed at either 4 degrees C or 38 degrees C can be used under field conditions to evaluate immune status of neonatal goats in the tropics.

Effects of various induced local environmental conditions and histopathological studies in experimental Dermatophilus congolensis infection on the bovine skin.

Although localised to the site of inoculation, experimental cutaneous streptothricosis was readily produced on scarified and/or defatted bovine skin infected with nutrient broth cultures of Dermatophilus congolensis. There was no difference in the extent and duration of lesions produced by either method. D congolensis failed to infect intact normal skin. Simulated rainfall and insect bite did not effect spread and production of generalized streptothricosis. On the other hand, localised experimental lesions regressed more rapidly when subjected to simulated rainfall. The histopathological changes were characterised by invasion of hair follicles by the germinating hyphae and mycelia of D gongolensis, accumulation of neutrophilic exudate beneath the infected epidermis, migration of some neutrophils through the epidermis resulting in intra-epidermal microabscess formation and regeneration of new epidermis from follicular sheath epithelium.

Detection of Mokola virus neutralising antibodies in Nigerian dogs.

Five hundred healthy Nigerian dogs were randomly selected and bled for serological detection of antibodies to lyssa-viruses, including Mokola, Lagos bat and Duvenhage viruses. The canine sera were screened for virus neutralising antibodies by a modification of the rapid fluorescent focus inhibition technique. Three serum samples were seropositive to Mokola virus but all were negative to Lagos bat and Duvenhage viruses. The three seropositive Mokola samples were also negative for rabies virus neutralising antibodies. This finding may explain occasional rabies-like canine mortalities within one year of antirabies vaccination in Nigeria.

Detection of rabies virus antibodies in fruit bats (Eidolon helvum) from Nigeria.

Fruit bats (Eidolon helvum) were collected from three different localities in Western Nigeria: Oti, Ibadan and Idanre. Fifty serum samples were analyzed using a modified rapid fluorescent focus inhibition technique against rabies, Mokola, Lagos bat and Duvenhage viruses. Twenty-five brain samples were screened for rabies and related lyssavirus antigens by direct fluorescent antibody microscopy and by an indirect fluorescent antibody technique with rabies anti-nucleocapsid monoclonal antibodies. All brain samples were negative. Two serum samples had relatively high anti-rabies activity; no neutralizing activity was detected against Mokola, Lagos bat or Duvenhage viruses.

The serological response of young dogs to the Flury LEP strain of rabies virus vaccine.

The serological response of puppies from Nigeria to live Flury low egg passage (LEP) rabies vaccine was determined. Two sets of puppies were used: one set from rabies-vaccinated bitches and another set from non-vaccinated bitches. Puppies were vaccinated intramuscularly with Flury LEP strain rabies vaccine and serially bled from the 4th week to the 30th week. Serum rabies virus neutralizing antibodies (VNA) were measured by a modified rapid fluorescent focus inhibition test (RFFIT). Puppies from non-vaccinated bitches responded well to vaccination after the 4th week and through to the 10th week of age, showing a progressive increase in VNA. In contrast, puppies from vaccinated bitches responded well to rabies vaccination only at 10 weeks of age, although detectable maternal rabies VNA and rabies anti-ribonucleoprotein (RNP) antibodies had decreased by 6 weeks post partum.

Haematological values of Nigerian goats and sheep.

Haematological parameters were determined in healthy Nigerian breeds of goats and sheep. Most values in the Nigerian goats were similar to those reported for temperate breeds of goats although the haemoglobin concentrations and the MCHC were lower. The haematocrit, haemoglobin concentrations and red cell counts of the West African Dwarf sheep were lower while the MCV were higher than those reported for sheep in the temperate climate. RBC values decreased with age in both Nigerian goats and sheep. Although sex pregnancy appeared to have little or no influence on the erythrocytic values, pregnant ewes had higher haematocrit and haemoglobin values. The low erythrocytic values were attributed to a low but constant parasitic burden which affected the flocks studied. Total leucocyte counts were considerably higher in the Nigerian goats and sheep than those reported for temperate breeds of animals. Young goats had higher total leucocyte counts while pregnant goats had reduced leucocyte counts. The leucocytic values were not affected by age and sex. Pregnant ewes also had higher leucocyte counts than non-pregnant ewes and rams.

Studies on west African dwarf sheep: incidence of perinatal mortality in Nigeria.

A study was conducted on the incidence of perinatal lamb mortality with extension up to 30 days of age (PMR 30) in West African Dwarf sheep in Ibadan, Nigeria, over a three year period. An overall PMR 30 of 19.9% was recorded. This consisted of an abortion rate of 3.0%, a still-birth rate of 2.7% and a neonatal lamb mortality rate of 15.6% up to 30 days of age (LMR). Abortion rate was significantly higher in pregnancies with multiple foetuses and during the dry sea son (P less than 0.01 and P less than 0.05 respectively). Conversely, the still-birth rate was slightly higher in single lambs (P less than 0.05). The LMR for males (17.1%) and that for females (13.4%) were not significantly (P greater than 0.05) different. Also the LMR for single-born (14.4%), twin-born (15.4%) and triplets (26.7%) did not significantly differ (P greater than 0.05). The optimum birth weight for survival of the breed appeared to be 2.6 to 3 kg. Regression analysis showed a 28.3% increase in birth weight and all live-born lambs with birth weights of 0.9 kg or less died during the neonatal period. About two-thirds (67.2%) of all neonatal deaths occurred during the first week of life. There was no significant effect of season on LMR. The perinatal mortality rates recorded among West African Dwarf sheep in this study do not seem to significantly differ from corresponding figures recorded in other parts of the world.

West Nile virus infection of adult mice by oral route.

Adult Swiss albino mice were fed orally with suspensions of a strain of West Nile virus isolated in Nigeria. Most of these mice became sick and died 7 days post feeding and virus was recovered from organs of such infected mice. Histological lesions were observed in some tissues and antibody to the strain of West Nile virus developed in mice that survived infection.

Prevalence of antibodies against Babesia canis in dogs in an endemic area.

A survey of 287 dogs for antibodies against Babesia canis in dogs in an endemic area, using ELISA, produced a prevalence of 43 per cent. Antibodies occurred in dogs of all age groups, the prevalence being significantly lower in dogs aged 1 to 6 months than in older dogs. There were no differences between indigenous Nigerian dogs and exotic (foreign) dogs; and between the sexes in the prevalence of antibodies. Antibodies were more prevalent in dogs with B. canis parasitaemia and in those with a higher risk of infection. Also antibodies were detected in some puppies born to seropositive bitches. The ELISA test failed to detect antibodies in 36.1 per cent of dogs with B. canis parasitaemia.