No abstract available.

In 1908 a Pan-African Veterinary Conference formed part of the inauguration ceremony of the Onderstepoort Veterinary Laboratory. Attended by 18 delegates from 12 countries in southern Africa, including the four colonies and three protectorates forming British South Africa, Rhodesia, German South West Africa, Portuguese East Africa, Madagascar and the Belgian Congo, discussions focussed on the animal diseases of the region with the emphasis on trypanosomosis (nagana) and East Coast fever. The successful meeting was followed by a series of similar conferences held in different African countries during the first half of the 20th Century.

The occurrence of genetic exchange is not only a fundamental property of an organism but its occurrence provides us with methods of analysis that can be used to dissect the basis of important traits. This paper will review the current evidence for a sexual cycle in Trypanosoma brucei and illustrate how genetic analysis can be used as a tool to identify genes of relevance to the disease, its treatment and transmission. The role of this process in the generation of diversity in the field will be illustrated by considering populations of the three sub-species of T. brucei and how the availability of genome sequence data has been exploited to study whether genetic exchange occurs in the trypanosomes infecting livestock. Finally, the use of population genetics as a methodology to identify genes under selection will be discussed and this will be illustrated as an approach to validating markers for drug resistance with examples from other parasitic protozoa.

Vaccination is an important disease prevention and control measure; however, vaccine adoption by livestock farmers in Tanzania is still low. This cross-sectional study examined the challenges to vaccine use faced by livestock owners and animal health professionals (AHPs) in Tanzania. A questionnaire was administered to 216 households that kept small ruminants and poultry and 19 AHPs’ data were collected electronically via the survey platform Qualtrics, and descriptive statistics were performed. Households with poultry reported vaccinating mostly against Newcastle disease (91.7%), fowl pox (48.1%) and Gumboro disease (37.0%), whilst households with small ruminants reported contagious caprine pleuropneumonia (62.2%), sheep and goat pox (17.1%), foot-and-mouth disease (7.3%) and peste des petits ruminants (7.3%). The households’ decision to vaccinate was mostly influenced by knowledge of diseases (82.4%), disease history on the farm (69.4%) and vaccine price (63.4%). Most households (54.6%) experienced challenges when purchasing vaccines, including high vaccine cost (78.0%), long distance from vaccine source (61.0%) and vaccine unavailability (21.2%). The findings suggest that improving the knowledge of livestock owners regarding the priority diseases and the benefits of vaccination, establishing more vaccine suppliers, improving vaccine distribution and access and training AHPs and households on appropriate vaccine storage and handling are necessary to improve vaccine adoption and ensure vaccine quality and effectiveness.

No abstract available.

No abstract available.

The declining efficacy of acaricide treatment as a means of reducing the prevalence of Theileria parva infections in sub-Saharan Africa has intensified efforts to achieve control through immunization of susceptible cattle. The infection and treatment method of immunization has enjoyed a resurgence with the availability of more effective cold chain facilities, although concerns remain regarding the possibility of vaccine strains spreading in local tick populations. In addition, an in-depth understanding of protective mechanisms deployed by immune cattle and the antigens targeted by them has led to substantial progress in the development of candidate subunit vaccines against both sporozoite and schizont stages of the parasite. The likely success of these vaccines, as well as infection and treatment immunization, will ultimately depend on the extent to which they disturb the endemic status of the parasite. These issues are discussed in the light of recent information on the genotypic diversity of T. parva in the field and the extent to which this is compromised by the immune response.

As we join Onderstepoort in celebrating its centenary, it is worth reflecting that tick-borne infections of wildlife and livestock have been part of everyday life in Africa for many, many generations. While much has changed since Watkins-Pitchford started developing short-interval dipping trials with arsenicals to contain the new epidemic of East Coast fever in southern Africa 100 years ago, when it comes to the impacts of tick-borne infections, many of the same challenges remain.

African horsesickness (AHS) played a major role in the history and development of southern Africa, both in times of peace and of war. Frequent epidemics of AHS resulted in major transportation impediments.The viral (filterable) nature of the aetiological agent was proven in 1900 by Sir John M'Fadyean in London, making it one of the first animal diseases for which this had been demonstrated. Similarly, the cultivation of AHS virus in the brain of mice and its subsequent attenuation were also amongst the first such feats for animal viruses. Interestingly, both milestones followed the initial work of Max Theiler (son of Sir Arnold) with yellow fever virus.