Foot-and-mouth disease (FMD) is an acute, highly contagious viral infection of domestic and wild cloven-hoofed animals. The virus is a single-stranded RNA virus that has a high rate of nucleotide mutation and amino acid substitution. In southern Africa the South African Territories (SAT) 1-3 serotypes of FMD virus are maintained by large numbers of African buffaloes (Syncerus caffer), which provide a potential source of infection for domestic livestock and wild animals. During February 2001, an outbreak of SAT-2 was recorded in cattle in the FMD control zone of South Africa, adjacent to the Kruger National Park (KNP). They had not been vaccinated against the disease since they form the buffer between the vaccination and free zones but in the face of the outbreak, they were vaccinated as part of the control measures to contain the disease. The virus was, however, isolated from some of them on several occasions up to May 2001. These isolates were characterized to determine the rate of genetic change in the main antigenic determinant, the 1D/2A gene. Nucleotide substitutions at 12 different sites were identified of which five led to amino acid changes. Three of these occurred in known antigenic sites, viz. the GH-loop and C-terminal part of the protein, and two of these have previously been shown to be subject to positive selection. Likelihood models indicated that the ratio of non-synonymous to synonymous changes among the outbreak sequences recovered from cattle was four times higher than among comparable sequences isolated from wildlife, suggesting that the virus may be under greater selective pressure during rapid transmission events.

Spirocerca lupi (Spirurida: Spirocercidae) is a cosmopolitan parasite, principally of domestic dogs and dung beetles are its main intermediate hosts. In South Africa there has recently been growing concern over the upsurge of reported cases of clinical spirocercosis in dogs, while little is known or understood about the dynamics of the host-parasite associations between dung beetles and this nematode. We determined and compared the prevalence of infection in dung beetles between rural, urban and periurban areas of Tshwane (Pretoria) Metropole. Dung beetles were sampled during April and October 2006, at various localities in each of these areas. Localities were selected on the basis of being focal areas of high infection with S. lupi in dogs. Pig, dog and cow dung-baited pitfall traps were used for sampling the beetles. Trap contents were collected 48 h after the traps had been set and only dung beetles were collected from the traps. In total, 453 specimens belonging to 18 species were collected from 63 pitfall traps in all three areas. The numbers of species that were collected varied among the three areas. Dung beetles, irrespective of species (18) and numbers (447), predominantly preferred pig dung. The prevalence of dung beetles infected with the larvae of S. lupi varied considerably in the three areas. In the urban area 13.5 % of the dung beetles dissected were infected, while the prevalence of S. lupi in dung beetles in the rural area was 2.3 %. All the dung beetles that were infected with this nematode showed a preference for omnivore (pig and dog) dung.

During parasitological field surveys of freshwater fish, sebekiid and subtriquetrid pentastome larvae were recovered from the body cavity or swim bladder of several fish species from various localities in Limpopo and Mpumalanga Provinces, South Africa. Sebekia wedliwas recovered from the body cavity of Marcusenius macrolepidotus (Mormyridae) from Flag Boshielo Dam, Limpopo Province, and Alofia sp. and Subtriquetra rileyi were found in the swim bladder of Oreochromis mossambicus (Cichlidae) from the Phalaborwa Barrage, Limpopo Province. The latter species was also collected from the swim bladder of O. mossambicus in dams in the Phalaborwa region and the Ga-Selati River, Limpopo Province. A single specimen of Sebekia okavangoensis was present in the body cavity of Clarias gariepinus (Clariidae) in a dam on a sugarcane farm in the Komatipoort region, Mpumalanga Province. Pentastomid infections in the Mormyridae and Clariidae represent new host records.

A Fluorescence resonance energy transfer (FRET) real-time reverse-transcription (rRT-PCR) assay was developed that distinguishes stains of South African and European highly pathogenic (HPAI) from low pathogenicity (LPAI) H5 avian influenza viruses in the absence of virus isolation, irrespective of the length of insertion at the hemagglutinin cleavage site (H0). The assay was used to pathotype H5-type viruses detected by rRT-PCR in ostrich tracheal swabs collected during the 2006 HPAI H5N2 outbreak in the Western Cape Province.

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.

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.

This studyw as carried out to establish whether cattle can develop resistance to re-infectionby Calicophoron microbothrium by assessing the response of intestinal mucosal globule leukocytese, osinophils, mast cells and basophils, and the establishment of the parasite in the host. A total of 241-year old Tuli steers were randomly divided into four groups of six animals each and infected with C. microbothriumm etacercariae. On the first day of the study, animals in Groups I and II were immunized with 5000 metacercariae and then challenged with 15000 metacercariae on Day 150 post immunization. Animals in Group III were immunized with 15000 metacercariae at the same time that Groups I and II animals were challenged to act as a positive control group Animals in Group IV were left uninfected and acted as a negative control group. Three animals from each group were slaughtered on Day 28 post-challenge and the remainder were slaughtered on Day 42 post-challenge. The established amphistomes were recovered and histopathological and cytological examinations were done on the jejunum, duodenuma, bomasum and the rumen. The establishment rates of the challenge infection in the immunized and challenged groups were lower and ranged from 0 to 0.2% as compared to 6% from naive animals infected as positive controls. Animals immunized and then challenged with C. microbothrium had significantly higher eosinophil, mast cell and globule leukocytes counts in the intestinal mucosa (P < 0.05) as compared to those of the control group. The study indicates that cattle can develop resistance to C. microbothrium re-infection and that eosinophils and mast cells may be important cells in the rejection of the parasite.

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 > 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.

The macroscopic features of the venous drainage of the reproductive system of the male ostrich were studied in six pre-pubertal and three sexually mature and active birds. Each testis was drained by one to four testicular veins. The right testicular veins drained the right testis and epididymis and its appendix to the caudal vena cava and to the right common iliac vein, whereas the left testicular veins drained the left testis and epididymis and its appendix exclusively to the left common iliac vein. A number of variations in the drainage pattern based on the point of entry and number of testicular veins were observed. The cranial aspect of the testis was also linked to the caudal vena cava or common iliac vein via the adrenal veins. The cranial, middle and caudal segments of the ductus deferens (and ureter) were drained by the cranial, middle and caudal ureterodeferential veins respectively, to the caudal testicular veins, the caudal renal veins and pudendal / caudal part of the internal iliac veins. In some specimens, the caudal ureterodeferential veins also drained into the caudal mesenteric vein. The surface of the phallus was drained by tributaries of the pudendal vein. The basic pattern of venous drainage of the reproductive organs of the male ostrich was generally similar to that described for the domestic fowl. However, important differences, including the partial fusion of the caudal renal veins, drainage of the cranial aspect of the testes via the adrenal veins, drainage of the caudal ureterodeferential veins into the caudal mesenteric vein and the presence of veins draining the surface of the phallus, were observed. Although significant, these differences may simply reflect variations in the normal pattern of venous drainage of the reproductive tract of birds which could be verified by studying more specimens and more species.

The study is the result of analyzing 16 895 blood smears of cattle collected at 180 sites in the provinces of Manica, Sofala, Zambézia and Tete in Mozambique. Of the blood smears 73.9 % were from Manica, 11.8 % from Tete, 8.5 % from Sofala and 5.8 % from Zambézia; 75.6 % of these were collected from smallholder cattle. Infections with trypanosomes were highest in smallholder cattle from Sofala Province with 36.8 % of the 872 blood smears examined positive for trypanosomes, and lowest in cattle of commercial farmers in Manica Province with only 6.2 % of 2 252 blood smears being positive. Trypanosoma congolense was the predominant species, followed by Trypanosoma vivax and Trypanosoma brucei sensu lato. Trypanosoma brucei, which also infects humans, was more frequent in the districts of Buzi, Mutarara and Morrumbala with 15.1 %, 10.5 % and 9.8 % of all examined cattle in 2005 being infected with it, respectively. The results show a significant increase in the infection rate with trypanosomes compared with results obtained in previous years by the Regional Veterinary Laboratory in Manica Province and by the Regional Tsetse and Trypanosomiasis Control Programme in Zambézia, Tete and Sofala provinces.