How does leishmaniasis spread?

Leishmaniasis is a parasitic disease spread by the bite of infected female phlebotomine sandflies, which are small (2-3 mm), hairy flies that feed on blood. The sandflies become infected when they feed on an infected person or animal. When an infected sandfly bites a person, the parasites (Leishmania spp.) are introduced into the person's skin. Inside the human host, the parasites multiply and spread to different parts of the body, depending on the species of _Leishmania_. The most common forms of leishmaniasis are:

1. Cutaneous leishmaniasis: This is the most common form, characterized by skin sores at the site of the sandfly bite. The sores may start as small, red bumps that gradually enlarge and develop a central ulcer.

2. Mucocutaneous leishmaniasis: This form affects the skin and mucous membranes, particularly in the nose, mouth, and throat. It can cause severe damage to the affected tissues and lead to disability.

3. Visceral leishmaniasis (kala-azar): This is the most serious form of leishmaniasis and affects the internal organs, including the spleen, liver, and bone marrow. It can lead to fever, weight loss, weakness, and enlargement of the spleen and liver.

Leishmaniasis is not directly transmitted from person to person. Transmission only occurs through the bite of an infected sandfly.