Risk factors associated with taeniosis-cysticercosis in rural farming communities in Gauteng Province, South Africa.

The aim of this study was to determine which of the livestock management and human practices known to be risk factors associated with taeniosis-cysticercosis occur in Gauteng Province. A questionnaire survey was conducted in two regions of Gauteng Province, Germiston and Pretoria. Results revealed that almost 20% of the interviewed farmers do not have toilets, most of them let their animals roam freely during the day for grazing and scavenging, and 47% use streams as the water source for their animals. This may create an infection opportunity through ingestion of Taenia-contaminated herbage or water. Furthermore, 26% mentioned that their animals might have access to human excreta. More than 70% of farmers in the province slaughter cattle and pigs for their own consumption without inspecting meat for cysticercosis. Only a few of the interviewed farmers in both regions were aware of the taeniosis-cysticercosis complex. Backyard slaughtering, consumption of uninspected meat by the public, poor livestock management, and limited sanitation in rural communities of Gauteng Province are identified as risk factors associated with the occurrence of Taenia saginata and Taenia solium infections in the province. Taenia saginata and T. solium are considered to have a global distribution; therefore, these risk factors may be applicable globally, not just in Gauteng Province. Programs on public awareness with regard to transmission and prevention of Taenia infections as well as more detailed studies on risk factors of taeniosis-cysticercosis are recommended.

Sero-prevalence of Taenia spp. infections in cattle and pigs in rural farming communities in Free State and Gauteng provinces, South Africa.

The aim of this study was to determine sero-prevalence of bovine and porcine cysticercosis in cattle and pigs in rural farming communities in Free State and Gauteng Provinces, Republic of South Africa. Blood samples were collected for a period of twelve months from live cattle (n=1315; 1159) and pigs (n=436; 240) and the serum extracted and stored before analysis by a monoclonal antibody based (HP10) antigen detection ELISA. Results revealed a generally high sero-prevalence and wide distribution throughout the two provinces with Free State having a higher sero-prevalence in both cattle and pigs (23% and 34%) than Gauteng province (15% and 14%). Consumption of infected meat that is either not inspected/missed at meat inspection; poor livestock management practices and limited sanitation in rural communities might have contributed to the occurrence of Taenia spp. infections in the two provinces. It is therefore, recommended that cysticercosis status of animals be established before slaughter. This would assist in ensuring that infected animals are not slaughtered for human consumption or zoonosis preventive measures are taken. Furthermore, public awareness programs on life cycles of T. saginata, T. solium and T. hydatigena and the use of more sensitive diagnostic tools are recommended as part of effective control strategies against taeniid infections.

A study of some infectious causes of reproductive disorders in cattle owned by resource-poor farmers in Gauteng Province, South Africa.

Two hundred and thirty-nine cattle from Gauteng Province in South Africa were tested for various pathogens causing reproductive diseases includingbovine viral diarrhoea/mucosal disease (BVD/MD) virus, infectious bovine rhinotracheitis/infectious pustular vulvovaginitis (IBR/IPV) virus, Neospora caninum and Brucella abortus usingvarious tests. For BVD/MD virus, 49.37% tested positive, 74.47% for IBR/IPV virus, 8.96% for Neospora caninum and 3.8% for Brucella abortus. The result for Brucella abortus is higher than the national average, possibly due to the small sample size. A high seroprevalence of antibodies to both BVD/MD virus and IBR/IPV virus was evident. These 2 viruses should be considered, in addition to Brucella abortus, when trying to establish causes of abortion in cattle. The clinical significance of Neospora caninum as a cause of abortion in Gauteng needs further investigation. One hundred and forty-three bulls were tested for Campylobacter fetus and Trichomonas fetus, and a low prevalence of 1.4% and 2.1% respectively was found in this study. The clinical implications of these findings are discussed.

A serological survey of bovine babesiosis in northern and eastern Zimbabwe.

The geographical distribution of Babesia bovis and Babesia bigemina antibodies in communal herds in northern and eastern Zimbabwe was determined using the ELISA technique. The animals in different herds in the study region had different levels of natural exposure to B. bovis (mean 32%, range 0-79%) and B. bigemina (mean 52%, range 5-92%) infections. The majority of herds (90%) were endemically unstable for B. bigemina and 62% were unstable for B. bovis. Natural region 5 and Manicaland province had the highest seroprevalence of B. bovis infection, while natural region 5 and Masvingo province had the highest seroprevalence of B. bigemina infection.

Observations on the use of Anaplasma centrale for immunization of cattle against anaplasmosis in Zimbabwe.

A total of 93 Bos taurus cattle was used in pen trials to compare vaccine stocks of Anaplasma centrale from South Africa and Australia (which stock came from South Africa in 1934) in protecting against three virulent field isolates from clinical Anaplasma marginale infections. In addition, field observations were made on the use of a vaccine, prepared from the Australian stock, in over 9553 cattle of mixed age and breeds on 16 co-operator farms and at one communal dip. The results of the pen trials indicated that the two vaccine stocks were comparable and that neither provided adequate protection against two of the three isolates of A. marginale. The field observations indicated that the vaccine was highly infective and produced mild reactions in most recipient cattle, and that users were generally satisfied with the vaccine. These somewhat conflicting results are discussed in the context of observations in Australia and future vaccination against anaplasmosis in Zimbabwe.

Evaluation of an ELISA for detection of antibodies to Babesia bovis in cattle in Australia and Zimbabwe.

An enzyme-linked immunosorbent assay (ELISA) for antibodies to Babesia bovis was evaluated in comparison with the indirect fluorescent antibody test (IFAT) in Australia and Zimbabwe. Positive and negative threshold values for the ELISA were set using sera from cattle of known infection status. Sensitivity and specificity estimates for the ELISA based on 158 positive sera from cattle experimentally infected with Australian isolates of B. bovis and 318 negative sera collected from B. bovis-free herds in Australia were 100% and 99.4%, respectively. The specificity of the assay in Africa, based on 328 sera from B. bovis-free herds in Kenya and South Africa, was 99.7%. The ELISA was compared with the IFAT using sequential sera from 16 calves experiencing primary B. bovis infections, and a total of 777 field sera collected from B. bovis-endemic herds in Australia and Zimbabwe. In primary infections, the ELISA and IFAT detected antibodies at or about the same time. With sera from endemic herds, the performance of the ELISA was at least comparable with that of the IFAT. Two hundred and fourteen of 221 sera that were negative by IFAT, were negative by ELISA, and 428 of 439 sera that were clearly positive by IFAT were positive by ELISA. Of 117 sera that gave equivocal (suspect or weak positive) results in the IFAT, 20 were positive by ELISA, 7 were suspect and 90 were negative. We conclude that the ELISA will be useful for epidemiological studies on B. bovis in Australia and Zimbabwe, and probably elsewhere.