Recent observations on site reactions in cattle to vaccination against contagious bovine pleuropneumonia (CBPP) using T1/44 vaccine in Zambia

Contagious bovine pleuropneumonia (CBPP), a highly infectious and fatal disease of cattle present in many countries in sub-Saharan Africa, is usually controlled by mass vaccinations. However, vaccination against CBPP is known to cause site reactions in a percentage of cattle especially in primary vaccinations. In Zambia, a record of site reactions was kept for seven consecutive years from 2005 to 2011 to establish the level of the problem. In some areas, after 3 years of consecutive vaccination campaigns, immunization could not be implemented for a period of 2 years because of logistical difficulties or owner resistance. Whereas in the three preceding years when animals were vaccinated annually, site reactions were in the range of 6.2%; on resumption of vaccination in the herds that had not been immunized for 2 years, site reactions averaged 21.3%. This data shows that the T1/44 vaccine may cause severe local reactions in cattle if there is any break in annual vaccinations. It is therefore important for authorities to ensure that the cattle at risk of contracting CBPP are regularly vaccinated to avoid discouraging farmers from presenting their animals.

Risk analysis of an anthrax outbreak in cattle and humans of Sesheke district of Western Zambia

An anthrax outbreak occurred in November 2010 in five villages of Sesheke district in Western Zambia. Control measures and data collection was carried out immediately the outbreak was reported. The prevalence of the disease in cattle was estimated at 7.4% (45/609) while the average herd size of infected cattle in affected villages was estimated at 121.8 (95% CI 48.8-194.8). Individual mortality per herd varied between 1.70% (3/179) and 20.25% (6/79). The relative risk of infection of cattle in the five affected villages varied between 0.18 (95% CI 0.4-5.7) and 3.7 (95% CI 1.99-6.68). In humans, the disease only affected three people and was characterized by cutaneous carbuncles. The ratio of infected persons per number of infected carcasses varied between 1:37 and 1:49 in affected villages while the overall ratio of people at risk to the number of carcasses was 42:1 indicating that despite availability of a large number of carcasses, human contact with infected carcasses was low. The findings of this study underline the importance of timely disease control measures in reducing the risk of human infections to anthrax in the face of an outbreak.