Comparison between c-ELISA and CFT in detecting antibodies to Mycoplasma mycoides mycoides biotype SC in cattle affected by CBPP in Botswana.

Contagious bovine pleuropneumonia (CBPP), caused by Mycoplasma mycoides mycoides biotype small colony (SC) (MmmSC) appears to be making a serious comeback in Africa after successful control programs in many parts of the continent during the 1960s and 1970s. Botswana, a country that has been free from the disease for more than 50 years, was affected in 1995. An eradication policy was adopted by the Government of Botswana in which 320,000 cattle in the affected district of Ngamiland, Northwestern Botswana were slaughtered. This was followed by a restocking exercise in which 70,000 cattle were sent to the outbreak areas as replacement stock. It became necessary to carry out serosurveillance in order to ensure that the disease did not reenter Botswana and to ensure that the replacement stock remained free from the disease. The specificity and sensitivity of the complement fixation test (CFT) in Botswana was assessed in 82 cattle affected by the disease and held in a double fenced quarantine camp. The newly developed competitive ELISA was made available to the National Veterinary Laboratory (NVL) through the FAO/IAEA Joint Division in Vienna, Austria. Using postmortem lesions as the gold standard and a 2 x 2 contingency table, the two tests were compared in terms of their sensitivity and specificity in detecting antibodies to MmmSC. The CFT was found to be slightly more sensitive than the c-ELISA, and this could be related to the stage of the disease. A long-term study comparing the progression of the disease with the two tests is, therefore, essential.

An outbreak of contagious bovine pleuropneumonia in Ngamiland district of north-western Botswana.

An outbreak of contagious bovine pleuropneumonia (CBPP) was detected in Botswana in 1995 after more than half a century of freedom from the disease. Lung tissues, pleural fluids, nasal swabs and serum samples were examined in laboratories in Botswana, South Africa and Namibia and the findings were confirmed in Italy. The disease was confirmed as CBPP from the gross and histopathological changes in the lungs of affected animals and by the culture of the agent of CBPP, Mycoplasma mycoides subspecies mycoides, small colony variant (MmmSC). These findings were supported by the demonstration of specific complement-fixing antibodies and the production of polymerase chain reaction products of MmmSC.