Seroprevalence and risk factors for Rift Valley fever and Capripoxvirus in small ruminants in the border region of Tanzania - Zambia

Sammanfattning: Tanzania is a country where poverty is still high and many households are dependent on agriculture to support their families. Small ruminants, such as sheep and goats, make up an important part of agriculture; they are cheap to buy and can easily be sold or exchanged for the farmers. The animals therefore function as a living bank and should unforeseen expenses arise, the money can be made available by selling an animal. This means that the health of these animals is important socio-economically for the farmers. Rift Valley fever (RVF) and sheep and goat pox (SGP) are two diseases that OIE have listed as notifiable. Rift Valley fever virus (RVFV) is an arbovirus transmitted by arthropod vectors such as mosquitoes. It is mainly infecting ruminants such as sheep, goats, cattle, buffaloes and camels, but is also a zoonotic disease and can infect humans. When domestic ruminants are infected, massive abortions can be seen in all stages in pregnant animals and a high fatality rate in young animals. Sheep and goat pox virus (SGPV) is a Capripoxvirus (CaPV) that belongs to Capripoxvirus genus. The virus is mainly transmitted through direct contact with infected animals, but indirect transmission through environment, or mechanical, through biting vectors, is also possible. Animals infected with SGPV show clinical signs of fever, loss of appetite, increased salivation and ocular and nasal discharge. After a few days, papules appear in the skin and on mucous membranes, even inside the body, which can cause serious and fatal complications. Young animals suffer more from the disease and the case fatality rate can be high. For farmers in rural communities, both diseases can have significant negative socioeconomic impact, due to the loss of production and animals. The gender-equality between men and women may also be affected since women often are the main caretaker of the livestock. This master thesis was performed as a Minor Field Study (MFS) that investigated the seroprevalence of RVF and SGP in Tanzania, in the two districts Momba and Tunduma close to the border of Zambia. The aim was to evaluate the seroprevalence in sheep and goats to understand the epidemiology of these diseases in the southwestern part of Tanzania and also investigate associated risk factors. Of the samples collected, 484 were from goats and 7 from sheep. Totally 16 of 491 analyzed samples were seropositive for RVFV, giving a seroprevalence of 3.3% on an individual level. All seropositive animals were goats, 93.8% females and 6.2% males. In total 31.7% (13/41) of the villages had seropositive animals, with a seroprevalence within the villages ranging up to 25%. The majority of the farmers reported that they utilized communal grazing system for their animals, where the majority of sheep and goats were reported to have daily contact with other domestic livestock. Only few sheep and goats had contact with wild ruminants. In this study, farmers buying their animals or had farmers in the same village buying their animals from markets, had significantly more seropositive animals In this study only a single animal was seropositive for CaPV, a female goat belonging to the Momba district.