Body lice are disease vectors and can transmit pathogens that cause human diseases such as epidemic typhus, trench fever, and relapsing fever. In developed countries, infestations are only a problem in areas of poverty where there is poor body hygiene, crowded living conditions and the lack of access to clean clothing. Outbreaks can also occur in situations where large groups of people are forced to live in unsanitary conditions. These types of outbreaks are seen globally in prisons, homeless populations, refugees of war, or when natural disasters occur and proper sanitation is not available.