- Leishmaniasis is a parasitic disease acquired through the bite of infected sandflies.
- Risk for skin infection (cutaneous leishmaniasis), the most common form in travelers to affected countries, is greatest for those with increased outdoor skin exposure.
- Disease begins with 1 or multiple skin lesions that evolve slowly from papules (bumps) to nodules (lumps) to ulcers.
- Most skin lesions resolve over time even without treatment. Destructive facial lesions of mucosal leishmaniasis resulting from late dissemination of certain forms of cutaneous leishmaniasis found in South America may rarely occur.
- Insect protective measures are recommended; no vaccines or drugs are available for prevention.
Leishmaniasis is a parasitic disease acquired through the bite of an infected sandflies. Multiple strains of the parasite exist, each of which may result in different disease manifestations. Most infected travelers present with cutaneous leishmaniasis, manifested by single or multiple nodules or ulcers on exposed areas of the skin. Mucosal leishmaniasis, manifested by destructive facial lesions, is a result of late spread of certain forms of cutaneous leishmaniasis which is found in South America. Visceral leishmaniasis, which affects internal organs and could be life threatening, is rarely found among travelers.
Leishmaniasis is found in 88 countries worldwide. Risk for cutaneous leishmaniasis is greatest for travelers to South and Central America, the Mediterranean region, the Middle East, or central Asia. Visceral leishmaniasis is rarely acquired in the Mediterranean region, which includes Spain and all of southern Europe.
Leishmaniasis is acquired through the bite of infected sandflies. Sandflies do not fly far during their life, and transmission may be restricted to specific locales and seasons in an affected country.
In temperate countries, transmission is restricted to summer months. In the tropics and subtropics, transmission may occur throughout the year. The parasites causing leishmaniasis may live and multiply in humans, domestic or stray dogs, and rodents.
Risk of infection depends on the likelihood of contact with infected sandflies, although cases have been reported in travelers exposed for only a single day. In the Eastern Hemisphere, sandflies characteristically rest in the cracks of human and animal dwellings and in rodent burrows, and they tend to be more active during the night. In the Western Hemisphere, sandflies are found in leaf litter and human and animal dwellings, and they may be active both day and night. In the forests of South and Central America, people who camp out at night or live in unscreened shelters are at greatest risk. Walking in leaf litter may stimulate resting sandflies to bite. Destruction of forests and increased urbanization have led to changes in sandfly behavior, thereby increasing the risk of acquiring leishmaniasis in towns and villages.
Risk for skin infection (cutaneous leishmaniasis), the most common form in travelers to affected countries, is greatest for those with increased outdoor skin exposure. The risk of acquiring cutaneous leishmaniasis appears to be highest in Suriname, Peru, Costa Rica, and Guatemala, possibly because many travelers to those countries engage in activities such as bird watching and eco-tourism that involve intense exposure in forested areas. Madidi National Park is an important site of exposure in Bolivia, the country that poses the greatest risk of mucosal leishmaniasis to travelers. Backpackers in Brazil are also at high risk.
The incubation period is extremely variable. For cutaneous leishmaniasis the incubation period averages several weeks, while for visceral leishmaniasis it is 3 to 9 months. Mucosal leishmaniasis develops from months to a few years after cutaneous lesions have healed.
Cutaneous leishmaniasis is the most common form of leishmaniasis in travelers. It begins with 1 or multiple lesions that evolve slowly from papules (bumps) to nodules (lumps) to ulcers with a central depression (crater) and hardened, raised borders. Less typically, crusted, nodular, non-ulcerated lesions may also occur. Ulcers usually occur on hands, arms, legs, and facial areas exposed to sandflies.
Mucosal leishmaniasis (espundia) uncommonly develops after the original skin lesions of some forms of cutaneous leishmaniasis found in South America have been treated or have healed. These particularly destructive lesions affect the nose, mouth, or throat. Initial symptoms include nasal obstruction, discharge, or nosebleed. Later symptoms include inflammation and perforation of the nasal septum (cartilage separating the 2 nostrils), with or without involvement of the soft palate, the skin of the nose, the back of the throat, the voice box, or the inner lining of the cheeks.
Consequences of Infection
Most skin lesions resolve over time even without treatment. These lesions resolve over a period of up to 2 years, leaving behind an atrophic scar. Destructive facial lesions of mucosal leishmaniasis—resulting from late dissemination of certain forms of cutaneous leishmaniasis found in South America—may rarely occur.
When to Seek Medical Attention
Individuals who develop a small (up to 2 inches) skin ulcer within 2 months of travel that does not heal within 2 weeks or more should seek medical attention and inform their health care providers that they may have been exposed to leishmaniasis.
For prevention, insect protective measures are recommended; no vaccines or preventive drugs are available. Travelers to risk areas should observe standard insect protective measures (see Insect Precautions), especially during times when sandflies are most active. Because sandflies are so tiny (approximately one-third the size of most mosquitoes), regular screens and bed nets might not be protective against them. Screens and bed nets should be of sufficiently fine mesh to keep sandflies out. Repellents and permethrin should be used, and long sleeves and trousers should be worn.