Risk, knowledge and preventive measures of smallholder dairy farmers in northern Malawi with regard to zoonotic brucellosis and bovine tuberculosis

Milk production using local cattle breed-types is an age-old practice in Malawi. Although dairy farming is becoming more common as a result of the increasing population and demand for milk and milk products, there is limited knowledge of the farmers' awareness of zoonotic disease risks, their preventative practices and the disease burden in animals. This study determined dairy farmers' general knowledge of zoonoses, assessed their risks for infection with zoonotic bovine tuberculosis (bTB) and brucellosis, and evaluated farm practices to prevent disease transmission. A questionnaire was drawn up and administered by the authors. It was used to collect information about the knowledge and preventive practices of 140 out of 684 registered dairy farmers at Mzuzu Agricultural Development Division, northern Malawi. During a second visit to 60 out of the 140 farms, a total of 156 and 95 cattle were tested for brucellosis and tuberculosis, respectively. Most farmers (77.1%) knew or had heard of zoonotic diseases, whilst 75.0% correctly named at least one zoonotic disease. More survey participants named tuberculosis as a zoonotic disease compared to brucellosis (74.3% versus 2.9%). The most commonly named means of transmission were milk (67.0%) and meat (56.0%). Almost all survey participants (96.4%) practised at least one farm activity that could lead to potential transmission of brucellosis or bTB, including sale (67.0%) and consumption (34.0%) of unpasteurised milk. Antibodies against brucellosis were found in 12 cattle (7.7%), whilst one animal (1.1%) reacted to the tuberculin skin test. General knowledge about possible transmission of diseases between humans and animals was high, although most farmers practised risk behaviours that could potentially expose the public to milk-borne zoonotic diseases such as brucellosis and bTB. Furthermore, some animals had positive results for brucellosis and tuberculosis tests. Therefore, improvement of zoonotic disease prevention programmes, as well as further investigation into the prevalence and risk factors for zoonoses, is recommended.