Urban and peri-urban agriculture and its zoonotic risks in Kampala, Uganda

Abstract

In developing countries, cities are rapidly expanding, and urban and peri-urban agriculture (UPA) has an important role in feeding a growing urban population. However, UPA carries risks of zoonotic disease transmission. This study aims to understand the characteristics of UPA in Kampala, Uganda and the zoonotic risks to humans. Following a general overview of the subject in Chapter 1, Chapter 2 describes the determination of urban, peri-urban and rural areas of the Kampala economic zone and socio-economical characteristics of the peri-urban interface compared with the urban and rural counter parts using the Village Characteristic Survey in 87 randomly selected Local Councils (LC1s). Chapter 3 describes the characteristics of UPA in Kampala and found both the contribution of agriculture to the livelihood and risks of zoonoses were high. In Chapter 4, the most important zoonotic diseases affecting populations living in urban and peri-urban areas in Kampala were identified; brucellosis, GI infections, Mycobacterium bovis tuberculosis and Taenia solium cycticercosis based on investigations using the medical records of Mulago National Referral Hospital. Chapter 5 describes a series of case-control studies of the identified most important zoonoses using a spatial approach. The risks of identified zoonoses might be homogenously high at all levels of urbanicity. Brucellosis appeared to be the most significant disease. Chapter 6 investigates brucellosis further, with an epidemiological investigation into the prevalence of the disease in milking cows and a quantitative analysis of the level of infection in milk for sale in and around Kampala. The prevalence was 6.2% (95%CI: 2.7-9.8) at the herd level. Chapter 7 describes the risk analysis for purchase raw milk infected with Brucella abortus in urban areas of Kampala. A quantitative milk distribution model was developed synthesizing the results from the cattle survey and interviews with milk sellers. The infection rates of milk at sale obtained from milk testing and cattle survey were multiplied to this model to present distribution of the risk. 11.7% of total milk consumed in urban Kampala was infected when purchased and the risk management analysis found the most effective control option for human brucellosis was construction of milk boiling centres either in Mbarara, the largest dairy production area in Uganda, or in peri-urban areas of Kampala.