Culicoides biting midges (Diptera: Ceratopogonidae) are responsible for the transmission of a large number of pathogens to livestock and wild animals. In this study the presence of the genus, using light traps based at four different sites within the National Zoological Gardens of South Africa, was investigated during 2002-2004. In total, 37 species were recorded, including large numbers of Culicoides imicola Kieffer, 1913, which is responsible for the transmission of economically important arboviruses in South Africa, Europe, Middle and Far East. These results are discussed with reference to the wider Culicoides fauna in the Onderstepoort area of South Africa, their vector competence as well as biosecurity at the National Zoological Gardens.

This study was carried out on 168 sheep in a private farm at Qena province. 128 out of them were apparently healthy, 22 clinically diseased suffering from respiratory affections and 18 were died at three weeks intervals. Bacteriological examination of the samples revealed that 42 samples were positive for bacterial isolation; 6 from apparently healthy animals, 20 from clinically diseased animals and 16 from dead ones. Bacterial isolates could be identified biochemically as P. multocida and P. heamolytica. Pathogenicity tests for P. multocida isolates indicated that the isolates were pathogenic to laboratory animals. P. multocida was isolated in high percentage (15%) in comparing with P. haemolytica (10%).

In this study five serotypes of E. coli were isolated from chickens and identified as O1, O2, O6, O78 and O126 out of 33 isolates derived from a total of 60 samples. SDS-PAGE revealed that four proteins were characteristic and shared in all these serotypes at the molecular weight of 21, 30, 55 and 74 kDa of which 55 and 74 kDa proteins were fully reacted with the antisera against E. coli in the western blot. Other proteins are present but varied from one serotype to another.

A total number of 28 buffaloes aged between 5-7years, body weight ranged between 400-500 kg, and belonged to private farms at Assiut Governorate constituted the materials of this study. Twenty of them showed the classical signs of hypophosphataemia while the other eight buffaloes were proved to be healthy by both clinical and laboratory investigations, used as control group. Biochemical analysis of blood sera showed a highly significant hypophosphataemia, hypocalcaemia and hypomagnesaemia in diseased buffaloes either pre or post treatment when compared with the healthy control ones. Meanwhile, the examination of blood showed marked decreases in erythrocytic count, haemoglobin concentration and packed cell volume in diseased animals. All parameters improved in affected buffaloes after 10 days of treatment. The chemical analysis of agronomical samples of soil and drinking water were done. The statistical analyses between the studied parameters were carried out in buffaloes before and after treatment.

The suitability of present and future climates for 30 Rhipicephalus species in Africa are predicted using a simple climate envelope model as well as a Division of Atmospheric Research Limited-Area Model (DARLAM). DARLAM's predictions are compared with the mean outcome from two global circulation models. East Africa and South Africa are considered the most vulnerable regions on the continent to climate-induced changes in tick distributions and tick-borne diseases. More than 50% of the species examined show potential range expansion and more than 70% of this range expansion is found in economically important tick species. More than 20% of the species experienced range shifts of between 50 and 100%. There is also an increase in tick species richness in the south-western regions of the sub-continent. Actual range alterations due to climate change may be even greater since factors like land degradation and human population increase have not been included in this modelling process. However, these predictions are also subject to the effect that climate change may have on the hosts of the ticks, particularly those that favour a restricted range of hosts. Where possible, the anticipated biological implications of the predicted changes are explored.

Tetrameres numida n. sp. from the proventriculus of Helmeted guinea fowls, Numida meleagris, in South Africa is described from eight male and four female specimens. The new species shares some characteristics with other Tetrameres species, but can be differentiated by a unique combination of characters. It bears two rows of cuticular spines extending over the whole length of the body and possesses two spicules. The left spicule measures 1 699-2 304 ?m and the right one 106-170 mm. Caudal spines are arranged in three ventral and three lateral pairs and the tail is 257-297 mm long. Diagnostic criteria of some of the previously described species of the genus Tetrameres from Africa and other parts of the world have been compiled from the literature and are included here.

The prevalence of Cryptosporidium spp. infection in a cross-sectional study of dairy cattle, from two contrasting dairying regions in Tanzania, were determined by staining smears of faecal samples with the modified Ziehl-Neelsen technique. Of the 1 126 faecal samples screened, 19.7% were positive for Cryptosporidium spp. The prevalence was lower in Tanga Region than in Iringa Region. The prevalence of affected farms was 20% in Tanga and 21% in Iringa. In both regions, the probability of detecting Cryptosporidium oocysts in faeces varied with animal class, but these were not consistent in both regions. In Tanga Region, Cryptosporidium oocysts were significantly more likely to be found in the faeces of milking cows. In Iringa Region, the likelihood that cattle had Cryptosporidium-positive faeces declined with age, and milking cattle were significantly less likely to have Cryptosporidium positive faeces. In this region, 7% of cattle were housed within the family house at night, and this was marginally associated with a higher likelihood that animals had Cryptosporidium-positive faeces. Our study suggests that even though herd sizes are small, Cryptosporidium spp. are endemic on many Tanzanian smallholder dairy farms. These protozoa may impact on animal health and production, but also on human health, given the close associations between the cattle and their keepers. Further studies are required to assess these risks in more detail, and understand the epidemiology of Cryptosporidium spp. in this management system.

In the present study, polymerase chain reaction (PCR) using random primer (E-20) was used to characterize and identify strains included in this study. Strains included 4 vaccinal reference strains of Pasteurella multocida, CU strain and 4 field isolates of Pasteurella multocida isolated from diseased turkeys which were identified biochemically and serologically as A:1, A:3, A3x4 and D:11. The obtained results revealed that all strains were reacted positively and in different manner with the E20 primer except the 2 field isolates. The results of these reactions demonstrated in terms of bands of different molecular weight specific to each strain. This can be used as a base for characterization and differentiation of strains involved in the present study as the 2 field strains A:1 and A:3 react with primer. Mouse protection test was performed by vaccination of mice with local fowl cholera oil adjuvant vaccine then challenge with virulent field strains A:1, A:3, D:12 and untypable isolates. Results revealed that the local fowl cholera adjuvant vaccine could protect mice against virulent challenge with A:1, A:3 and D:12 field strains but it could not be protect mice against untypable isolates

During 2005, velogenic Newcastle disease virus (NDV) caused a major outbreak among commercial broiler chicken in Egypt. The outbreak raised concerns regarding the protective immunity of commercially available vaccines for prevention and control of this virus in poultry. The virus was isolated from broiler farm suffered from more than 95% mortalities. The isolate was confirmed not to be avian influenza virus (AIV) by rapid chromatographic strip test, and characterized as NDV using reverse transcription-polymerase chain reaction (RT-PCR) which amplified a portion of the fusion gene of NDV and haemagglutination inhibition (HI) test. This isolate confirmed to be velogenic viscerotropic NDV by mean death time (MDT) test and pathogenicity to 7-week old chickens. We tried to determine whether the existing commercial live NDV La Sota vaccine could provide protection against the isolated virus or not. Birds received a single dose of live La Sota type vaccine at 3 weeks of age and were challenged 2 weeks postvaccination with a lethal dose of NDV. Results indicated that the live vaccine did not protect against morbidity but reduced mortality in comparison to controls. All unvaccinated control chickens challenged with NDV died within 5 days post-challenge (pc). Protection from disease did not correlate with the presence of antibody titers (determined by HI) at day of challenge. These results underscore the need to develop new NDV vaccines and vaccine strategies for use during outbreak situations to protect birds from both disease and infection and to reduce virus shedding.

A comparison of mean corpuscular volume (MCV) and packed cell volume (PCV) was made between cattle undergoing lethal and non-lethal reactions following experimental infections with the apicomplexan protozoa, Theileria parva Katete. This work confirmed that anaemia occurs in infected animals. However, the fall in PCV was steeper in lethal reactions compared to non-lethal reactions. Our results show that animals with initially lower MCV values are more prone to fatal reaction, despite having normal PCV profiles. The study also found that small red blood cells are more likely to be infected with T. parva. These findings suggest that animals with a higher proportion of small red blood cells in circulation will be more likely to succumb to T. parva infections. The potential for using MCV as a predictor of the outcome of infection challenge is discussed.