EPIDEMIOLOGY AND CONTROL OF PARASITES IN NOMADIC SITUATIONS

Nomadism is a highly specialised mode of life that enables humans to e xploit resources that are widely distributed over space and time. The isolation and remoteness of many nomad populations have limited studie s on the macroepidemiology of parasitic infection in nomad populations . From the available information, the influence of a number of factors on the prevalence and transmission of parasitic infections in nomads is discussed. Environmental conditions, especially relative humidity a nd temperature, profoundly influence parasitic diseases. Human behavio ur varies with cultural factors and influences exposure to disease. Pe riodic movements of nomads may either remove them and their animals fr om contaminated environments or may bring then into contact, often sea sonally, with infections. There may be a strong ecological interdepend ence between diet and infection and disease in nomadic groups. Finally , the influence of drought can be profound in that seasonal or prolong ed drought promotes concentration of populations in small areas or the ir sedenterisation, often with an increase in parasite transmission. R elevant information that needs to be acquired to develop appropriate p ractical and cost-effective health and veterinary care and control pro grammes for nomadic populations and their livestock is outlined.