Some observations on the sero-prevalence of heartwater and tick infestation in Zambian goats.

A survey was carried out to define the distribution of heartwater in goats that originated from six districts in communal grazing semi-arid areas of Zambia. A total of 181 samples (40.1%) out of 451 serum samples from adult goats were positive for Ehrlichia ruminantium antibodies after screening using indirect MAP-1B antigen ELISA technique with statistically significant differences (P < 0.01) between the six districts. Out of 1 036 adult goats examined for tick infestation, 105 were infested by ticks, with Amblyomma species being the most dominant tick encountered. Amblyomma variegatum, which is the vector for heartwater transmission in Zambia constituted 42.4% of the tick species, identified. The overall tick infestation rate was 10% while the tick:goat ratio was 2.1:1. Amblyomma variegatum appears to be widespread throughout the study area, as are antibodies to E. ruminantium.

A survey of trypanosomosis in Zambian goats using haematocrit centrifuge technique and polymerase chain reaction.

The incidence of trypanosomosis was determined using the haematocrit centrifuge technique (HCT) as well as polymerase chain reaction (PCR) on 120 goat blood spots on filter paper. Both techniques failed to detect a positive reaction, implying that factors such as age, healthy appearance and small sample size notwithstanding, trypanosomosis does not seem to pose a serious threat to goat health in the districts from where the animals originated.

Demonstration of erythrophagocytosis in Trypanosoma congolense-infected goats.

Anaemia is the most prominent clinical sign of trypanosomosis in domestic animals but little is known about its pathogenesis. This work investigated erythrophagocytosis as the possible cause of anaemia. Pathogenic Trypanosoma congolense (IL3000) was intravenously inoculated into six goats at 3x10(6) trypanosomes per goat. Six other goats were maintained as controls. The infection was studied for 10 weeks and parasitaemia, packed cell volume (PCV) and serum protein levels were determined. The amount of erythrophagocytosis was determined from the amount of 51Cr-labelled red blood cells (RBCs) phagocytosed by self mononuclear cells (MNCs) in vitro and by microscopically counting phagocytosed RBCs on Giemsa stained smears of incubated mixtures of RBCs and self MNCs. The infection resulted in trypanosomosis with rapid progressive anaemia and mean peaks of parasitaemia of about 3x10(3)ml(-1). In infected goats, a significant (P<0.05) mean reduction in PCV (of 37-22%) was observed starting from about 20 days up to 56 days post-infection. Within this same phase, significant (P<0.05) differences in mean radioactivity counts of (51)Cr incorporated into MNCs were observed with infected goats' samples having counts 50% higher than the control goats' samples. Microscopically, the mean number of phagocytosed RBCs in infected goats' MNCs was noted to be 80% higher (P<0.05) than that of control goats. Appreciable increases (P<0.05) in mean serum globulin levels, from 3.5 to 4.7g/dl, were observed within 3 weeks of infection. The study showed that erythrophagocytosis is an important mechanism leading to anaemia in the pathophysiology of T. congolense infection in Zambian goats.

Characterization of some Theileria parva stocks from Zambia using monoclonal antibodies.

Theileria parva parasites have been isolated from different location in Zambia where malignant theileriosis has been recorded. A total of 16 bovine lymphocytic cell lines infected with T. parva schizonts were characterized using a panel of anti-schizont monoclonal antibodies (MAbs). Comparison of the Theileria stocks isolated before (old) and after (new) the Muguga cocktail of T. parva from Kenya was used to vaccinate cattle against theileriosis in Zambia revealed differences in their reactivity against MAbs. The new isolates are showing MAb profiles similar to that exhibited by the Muguga cocktail which was used to vaccinate cattle in these areas between 1983 and 1989. These results suggest that the use of the Muguga cocktail to vaccinate animals against theileriosis in Zambia may have introduced Theileria stocks of different antigenic properties.

Spinal cord mensuration--a comparative study on the spinal cord segments and spinal nerves in Zambian goats.

It has been known that the relative length of spinal cord and its segmental volume in domestic animals has established that the dynamics of spinal cord is directly related with the functions of the limbs and in particular to their feeding habits. Bilateral rostrocaudal measurements of spinal nerves involving their root attachment length, root emergence length, interroot length, segment length and cross sectional area were recorded on the dorsal and ventral surfaces of each segment of the spinal cords of five local healthy Zambian goats. We identified that the brachial and lumbar enlargements have involved identical number of spinal cord segments. Brachial and lumbar enlargements extended from C6 to T1 and L4 to L7. The average length of spinal cord was 59.9 cm and it extended up to caudal end of 5th sacral vertebrae. The root emergence length appeared to decrease gradually from C2 segment, which remained less variable in thoracic and lumbar segments and then receded sharply through sacral segments. The dorsal nerves entered spinal cord over a greater area than ventral because of more spinal rootlets. The greatest segment length lied in mid cervical region and then from lumbar segment it decreased sharply up to the end of sacral segments. It is concluded that these goats have a feeding habit similar to that of cattle rather than resting their forelimbs on the shrubs while nibbling the leaves as recorded in Asian goats. It also confirmed that the shrubs were more drooping along with grasses in the Gwembe Valley of Zambia.

Aflatoxin levels in foodstuffs in Fiji and Tonga islands.

Fungal growth is a major problem of food storage in humid environments, as occur in South Pacific countries for parts of the year. Major crops, including edible nuts, copra and root crops, are susceptible to Aspergillus growth and therefore potential contamination with aflatoxin. Liver cancer occurs in Fiji and Tonga, with the occurrence in Fijians being significantly higher than in the Indian population. Thirty-three peanut samples from farmers were analysed for aflatoxin and 50% of the samples from Fiji were positive but only 9% from Tonga, reflecting different storage practices. Local copra, cassava, and maize samples were found contaminated, with only the maize at a serious level. Twenty-five plate food samples from Fiji showed low contamination. When starch foods from the Fijian diet left after cooking were analysed to follow potential aflatoxin development only sweet potatoes showed some contamination.