Leishmaniasis
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Leishmaniasis

Leishmaniasis is a parasitic disease that is found in parts of the tropics, subtropics, and southern Europe. Leishmaniasis is caused by infection with Leishmania parasites, which are spread by the bite of infected sand flies. There are several different forms of leishmaniasis in people. The most common forms are cutaneous leishmaniasis, which causes skin sores, and visceral leishmaniasis, which affects several internal organs (usually spleen, liver, and bone marrow). 


People of all ages are at risk for infection if they live or travel where leishmaniasis is found. Leishmaniasis is usually more common in rural than in urban areas; but it is found in the outskirts of some cities. The transmission risk is highest from dusk to dawn because this is when sand flies generally are the most active.


Signs and symptoms

Cutaneous leishmaniasis
People who have cutaneous leishmaniasis have one or more sores on their skin. The sores can change in size and appearance over time. The sores may start out as bumps or nodules, and may end up as ulcers, with a raised edge and central crater. Some leishmaniasis ulcers are covered by a scab. They can be painless or painful. Some people have swollen glands near the sores.

Visceral leishmaniasis
People who have visceral leishmaniasis usually have fever, weight loss, and an enlarged spleen and liver, and abnormal blood tests. People may have low blood counts, including a low red blood cell count (anemia), low white blood cell count, and low platelet count.


Transmission
The main route of infection is through the bite of infected female sand flies. Sand flies become infected by sucking blood from an infected animal or person. People might not realize that sand flies are present because:
  • They do not make noise when they fly;
  • They are small: they are only about one-third the size of typical mosquitoes or even smaller;
  • Their bites might not be noticed (the bites may be painless or painful).

Sand flies usually are most active in twilight, evening, and night-time hours (from dusk to dawn). Although sand flies are less active during the hottest time of the day, they may bite if they are disturbed (for example, if a person brushes up against the trunk of a tree or other site where sand flies are resting).

Some types (species) of Leishmania parasites may also be spread by blood transfusions or contaminated needles (needle sharing). Congenital transmission (spread from a pregnant woman to her baby) has been reported.


Incubation period
The skin sores of cutaneous leishmaniasis usually develop within a few weeks or months of the sand fly bite. People with visceral leishmaniasis usually become sick within months (sometimes as long as years) of when they were bitten.


Treatment
Treatment is available and varies depending on the type and severity of infection. The skin sores of cutaneous leishmaniasis often heal on their own without treatment. If not treated, severe (advanced) cases of visceral leishmaniasis can cause death.


Prevention
1. There are no vaccines or medicines available to prevent infection. The best way to prevent infection is to protect oneself from sand fly bites. To decrease the risk of being bitten:

2. Avoid outdoor activities, especially from dusk to dawn, when sand flies generally are the most active.

3. When outdoors (or in unprotected quarters):
  • Minimize the amount of exposed skin. To the extent that is tolerable in the climate, wear long-sleeved shirts, long pants, and socks; and tuck your shirt into your pants.
  • Apply insect repellent to exposed skin and under the ends of sleeves and pant legs. Follow the instructions on the label of the repellent. The most effective repellents are those that contain the chemical DEET (N,N-diethylmetatoluamide).

4. When indoors:

  • Stay in well-screened or air-conditioned areas.
  • Keep in mind that sand flies are much smaller than mosquitoes and therefore can get through smaller holes.
  • Spray living/sleeping areas with an insecticide to kill insects.
  • If you are not sleeping in a well-screened or air-conditioned area, use a bed net and tuck it under your mattress. If possible, use a bed net that has been soaked in or sprayed with a pyrethroid-containing insecticide (permethrin or deltamethrin). The same treatment can be applied to screens, curtains, sheets, and clothing (clothing should be retreated after five washings).

Some people have had cutaneous leishmaniasis more than once. Therefore, you should follow the preventive measures listed above whenever you are in an area where leishmaniasis is found.​

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