A Quantitative Risk Assessment of Human Exposure to Brucellosis Through the Consumption of Contaminated Raw Cow Milk in Arusha, Tanzania

Abstract

The study aimed at assessing the risk of exposure to brucellosis through the consumption of cow milk in the Arusha region, Tanzania. Primary data related to milk consumption was collected through a structured questionnaire from 400 cattle farmers. Data was directly coded and entered into IBM SPSS version 20 and analysed for frequencies and descriptive statistics. Stochastic Monte Carlo simulation in @ risk Software (Version 8.1) platform was used to estimate the risk of human exposure to brucellosis through the consumption of contaminated milk. Results revealed that 96.5% of the population consumed milk in three (3) portions: morning, afternoon, and night. More than 70% of the people in the area consume 500ml-1000ml of milk daily. People in rural settings (71%) reported consuming raw milk, compared to 10% of people in urban settings. The probability of getting infected with Brucella through the consumption of raw milk was estimated at 0.64 (95%CI 0.333-0.861). The model also predicted the number of people likely to get infected with Brucella in Arusha region in a one-year consumption period to be 1,084,358 (95%CI: 565,000-1458,000), out of 1,694,310 people following consumption of contaminated raw milk. The risk of exposure was estimated to be high when dairy cows were infected with Brucella at the farm and when the milk portions were consumed raw. The risk of human exposure to the Brucella pathogen is high. To reduce the risk of human exposure, there is a need to create awareness about brucellosis in the study communities concerning how the disease is transmitted to humans, its associated effects, and the preventive and control measures. Further studies are required to assess the risk of exposure to brucellosis through other pathways such as the consumption of soft cheese and contact with cattle.