The prevalence of Theileria equi and Babesia caballi infections in the north-eastern Free State Province of South Africa was determined by examination of thin and thick Giemsa-stained blood smears, IFAT and PCR. No parasites were detected by microscopy from any blood samples collected at five study sites, Qwaqwa, Kestell, Harrismith, Vrede and Warden. Of the tested serum samples, 28/29 (96.5 %), 20/21 (95.2 %) and 42/42 (100 %) were positive by IFAT for T. equi infections in Harrismith, Kestell and Qwaqwa, respectively, and 5/29 (17.2 %>), 13/21 (61.9 %>) and 30/42 (71.4 %>) were sero-positive for B. caballi infections in Harrismith, Kestell and Qwaqwa, respectively. All DNA samples from the study sites were negative for B. caballi infections by PCR, but five samples, two from each of Kestell and Warden and one from Vrede, were PCR positive for T. equi infections. The high prevalence of antibodies against T. equi and B. caballi in the sampled horses indicates that the animals had been exposed to T. equi and B. caballi infections but the absence of parasitaemia and very low number of positive PCR samples, however, imply that T. equi and B. caballi are endemically stable in the north-eastern Free State Province.

Experimental Trichinella zimbabwensis infections were established in three baboons (Papio sp.) and four vervet monkeys (Cercopithecus aethiops) and the clinical-pathological manifestations assessed. The infected animals showed clinical signs ranging from fever, diarrhoea, periorbital oedema and muscular pain in varying degrees. One baboon became blind due to the infection. Levels of creatinine phosphokinase and lactate dehydrogenase increased to reach a peak on Day 42 post-infection (pi) for both baboons and monkeys. Blood parameters such as packed cell volume, levels of red blood cells and white blood cells did not change significantly from the normal ranges except for the levels of eosinophils which peaked above the normal ranges at Day 28 and 56 pi in baboons and at Day 56 pi in monkeys. Two baboons and two monkeys died during the course of the experiment. They were emaciated and showed lesions such as ascites, hydropericardium, congested liver and enlarged gall bladder. Histopathological findings of various muscles included a basophilic transformation of muscle cells, the disappearance of sarcomere myofibrils and basophilic sarcoplasm with the presence of Trichinella larvae in the sarcoplasm. These changes were mainly in the massetter and were of various intensities in the tail, gastrocnemius and biceps muscles. Five consecutive treatments with an oxfendazole-levamisole combination on surviving animals failed to clear the infection whereas ivermectin cleared the infection after one treatment in two monkeys and after two treatments in a baboon.

Serum samples from 237 randomized rabbits from the five ecological zones of Nigeria, i.e. Northwest (NW), Northeast (NE), Southeast (SE), Southwest (SW) and Northcentral (NC), were evaluated for the presence of antibodies to Encephalitozoon cuniculi by the indirect immunofluorescent antibodies test. A titre of 10 or more was taken as positive. Thirty-nine (16.5 %) of the 237 samples were positive with 11, 10, 8, 6 and 4 seropositive rabbits occurring in the NW, NE, SE, SW and NC zones of Nigeria, respectively. Age, sex, live mass and access to grass as a feed supplement were not statistically (P &gt; 0.05) associated with seropositivity, but cage type (single-versus multi-rabbit type), contact with free-range rats and previous illness were strongly (P < 0.05) associated with it. The practice of selling unscreened and untreated 5 to 10-week-old weaners to prospective buyers as foundation stock, use of multi-rabbit communal cages, occasional release of rabbits in runs and contact with free-range house rats should be discouraged. Regular prophylactic and curative treatments, occasional serological screening to remove carriers, and the practice of a high level of hygiene in rabbit colonies are effective control measures.

In four Kenyan pig breeding units the pregnancy diagnosis of sows has been carried out in two groups: Group 1 (n = 1911): the sows were transrectaly pregnancy tested between Days 17-22 post-mating by ultrasound. Sows testing non-pregnant immediately received one dose of 400 IU pregnant mare serum gonadotropin (PMSG) (equine chorion gonadotropin, eCG) and 200 IU human chorion gonadotropin (hCG). On showing signs of oestrous, the animals were subsequently artificially inseminated (AI). Group 2 (n = 1923): sows were pregnancy tested by serum progesterone (P4)-based enzyme-linked immunosorbent assay (ELISA) on Day 17 post-breeding. P4 concentrations were categorized as positive (&gt; 5 ng/ml) or negative (< 5 ng/ml). Sows testing nonpregnant immediately received one dose of 400 IU PMSG and 200 IU hCG by injection, and were subsequently artificially inseminated. The following parameters were evaluated: sows diagnosed non-pregnant, days from first post-weaning insemination until the sows were inseminated at their first return to oestrus; farrowing rate and total piglets born and number of live-born piglets in litters. The percentage of sows diagnosed non-pregnant in the two groups, as well as the totals of born piglets and of live-born piglets in litters did not differ significantly between the two groups. The number of days from the first post-weaning mating until the sows were artificially inseminated at their first return to oestrus and the administration of eCG and hCG was shorter (P < 0.01) and farrowing rate was higher (P < 0.01) in the ELISA-tested sows.

The ability of intravenously administered lactose in normal saline to prevent a decline in packed cell volume (PCV) during experimental trypanosomosis was studied in Zebu cattle. During the lactose infusion period, the PCV was stable up to Day 5 post-infection (p.i.) in a lactose-infused group, compared to that in an uninfused group in which the PCV dropped significantly (P < 0.05) as shown by the values of cumulative percentage change. Furthermore the mean rate of change in PCV was significantly (P < 0.05) higher in the uninfused group relative to the lactose-infused group during the same period. While the PCV fell markedly in the lactose-infused group a day after lactose infusion was stopped (Day 13 p.i.), subsequent PCV values were significantly (P < 0.05) higher compared to those in the uninfused group, up to the end of experiment on Day 17 p.i. However the mean rates of change in PCV did not vary significantly (P &gt; 0.05) between the groups during the period in which lactose infusion was stopped. The mean levels of parasitaemic waves and parasitaemia were higher, more prolonged and more frequent in the lactose-infused group. It was inferred that the lactose was able to prevent an early onset of anaemia in the Trypanosoma vivax-infected Zebu cattle.

The seroprevalence of Anaplasma antibodies in wildlife (eland, blue wildebeest, kongoni, impala, Thomson's gazelle, Grant's gazelle, giraffe and plains zebra) and domestic animal (cattle, sheep and goat) populations was studied in wildlife/livestock interface areas of Kenya. Serum samples were analyzed by competitive inhibition enzyme-linked immunosorbent assay (CI-ELISA), using a recombinant antigen (MSP-5) from Anaplasma marginale surface membrane. A monoclonal antibody, FC-16, was used as the primary antibody, while anti-mouse conjugated to horseradish peroxidase was used as the secondary antibody. The results indicate a high seroprevalence in both wildlife and livestock populations, in contrast to earlier reports from Kenya, which indicated a low seroprevalence. The differences are attributed to the accurate analytical method used (CI-ELISA), as compared with agglutination techniques, clinical signs and microscopy employed by the earlier workers.

Freshwater snails are known to serve as first intermediate hosts for various parasitic diseases such as schistosomosis and fasciolosis. Snails were collected on several occasions in the proximity of Pretoria, South Africa and their cercarial sheddings were studied. This article describes three different types of cercariae shed by the freshwater snail, Lymnaea natalensis, viz. a fork-tailed cercaria of a Trichobilharzia sp., an avian parasite belonging to the family Schistosomatidae, an echinostomatid cercaria of the family Echinostomatidae, also avian parasites and a xiphidiocercaria of the family Plagiorchiidae which parasitise avians and amphibians. The morphology of these cercariae was studied by light and scanning electron microscopy.

This work reports the first molecular analysis study of chicken anaemia virus (CAV) in backyard chickens in Africa using molecular cloning and sequence analysis to characterize CAV strains obtained from commercial chickens and Nigerian backyard chickens. Partial VP1 gene sequences were determined for three CAVs from commercial chickens and for six CAV variants present in samples from a backyard chicken. Multiple alignment analysis revealed that the 6 % and 4 % nucleotide diversity obtained respectively for the commercial and backyard chicken strains translated to only 2 % amino acid diversity for each breed. Overall, the amino acid composition of Nigerian CAVs was found to be highly conserved. Since the partial VP1 gene sequence of two backyard chicken cloned CAV strains (NGR/Cl-8 and NGR/Cl-9) were almost identical and evolutionarily closely related to the commercial chicken strains NGR-1, and NGR-4 and NGR-5, respectively, we concluded that CAV infections had crossed the farm boundary.

A survey of helminth parasites was carried out on 198 dogs living in almost complete liberty in villages in the northeast of Gabon. Faeces and blood samples were collected and analysed. Dirofilaria immitis antigen was detected in 13.6 % of dogs using the SNAP 3Dx® test, a commercially available enzyme-linked immunosorbent assay (ELISA). Faecal examination revealed that 91.4 % of dogs were infected by intestinal helminths. Ascarids were found in 58.5 % of the samples. Trichuris vulpis was observed in 49.5 %> of cases, and Uncinaria spp. and Ancylostoma spp. in 34.8 %>, Spirocerca lupi in 25.3 % and Capillaria spp. in 10.6 %. Cestode embryophores were found in 8.6 % of the samples.

Four stocks of Ehrlichia ruminantium (Welgevonden, Ball3, Nonile and Blaauwkrans), the causative agent of heartwater in domestic ruminants, were isolated into Ixodes scapularis (IDE8) tick cells using the leukocyte fraction of the blood of infected sheep. Organisms of two of the E. ruminantium stocks (Welgevonden and Blaauwkrans) propagated in IDE8 cells were also successfully used to infect bovine endothelial cells. All stocks were successfully propagated in IDE8 cells using Dulbecco's modified Eagle's medium nutrient mixture Ham F-12 containing 10 % foetal bovine serum (FBS). The technique should be included in any attempt to isolate uncharacterized E. ruminantium stocks.