Leishmaniasis

Leishmaniasis

Leishmaniasis is a parasitic disease that is found in parts of the tropics, subtropics, and southern Europe.
1. eishmaniasis is caused by infection with Leishmania parasites, which are spread by the bite of phlebotomine sand flies. There are several different forms of leishmaniasis in people.
  1. 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).
Epidemiology
1. The number of new cases may vary or change over time and are difficult to estimate. For cutaneous leishmaniasis, estimates of the number of new cases per year have ranged from approximately 700,000 to 1.2 million or more.
  1. In the Old World (the Eastern Hemisphere), leishmaniasis is found in some parts of Asia, the Middle East, Africa (particularly in the tropical region and North Africa, with some cases elsewhere), and southern Europe. It is not found in Australia or the Pacific islands.
  2. In the New World (the Western Hemisphere), it is found in some parts of Mexico, Central America, and South America. It is not found in Chile or Uruguay. Occasional cases of cutaneous leishmaniasis have been acquired in Texas and Oklahoma.
Biology
1. Causal Agent:
  1. Leishmaniasis is a vectorborne disease that is transmitted by sand flies and caused by obligate intracellular protozoa of the genus Leishmania. Human infection is caused by more than 20 species. These include the L. donovani complex with 2 specie
2. Life Cycle:
Disease
1. The most common form is cutaneous leishmaniasis, which causes skin sores. The sores typically develop within a few weeks or months of the sand fly bite. The sores can change in size and appearance over time. The sores may start out as papules (bumps) or nodules (lumps) and may end up as ulcers (like a volcano, with a raised edge and central crater); skin ulcers might be covered by scab or crust. The sores usually are painless but can be painful. Some people have swollen glands near the sores (for example, under the arm, if the sores are on the arm or hand).
2. The other main form is visceral leishmaniasis, which affects several internal organs (usually spleen, liver, and bone marrow) and can be life threatening. The illness typically develops within months (sometimes as long as years) of the sand fly bite. Affected people usually have fever, weight loss, enlargement (swelling) of the spleen and liver, and low blood counts—a low red blood cell count (anemia), a low white blood cell count (leukopenia), and a low platelet count (thrombocytopenia).
3. Mucosal leishmaniasis is an example of one of the less common forms of leishmaniasis. This form can be a sequela (consequence) of infection with some of the species (types) of the parasite that cause cutaneous leishmaniasis in parts of Latin America: certain types of the parasite might spread from the skin and cause sores in the mucous membranes of the nose (most common location), mouth, or throat.
Diagnosis
1. Various laboratory methods can be used to diagnose leishmaniasis—to detect the parasite as well as to identify the Leishmania species (type). Some of the methods are available only in reference laboratories. In the United States, CDC staff can assist with the testing for leishmaniasis.
2. Tissue specimens—such as from skin sores (for cutaneous leishmaniasis) or from bone marrow (for visceral leishmaniasis)—can be examined for the parasite under a microscope, in special cultures, and by molecular tests. Blood tests that detect antibody (an immune response) to the parasite can be helpful for cases of visceral leishmaniasis; tests to look for the parasite (or its DNA) itself usually also are done
Treatment
1. Sodium stibogluconate Meglumine antimoniate
  1. They are first-line agents for cutaneous Mechanism of action: not determined , evidence for inhibition of glycolysis in the parasite at the phosphofructokinase reaction. Pharmacokinetics Available parenterally excretion: Urine
    1. Adverse effects: Pain at the injection site Pancreatitis elevated liver enzyme arthralgias
2. Miltefosine
  1. First orally active drug for viceral Leishmaniasis Mechanism of action: - interfere with phospholipids in parasitic cell membrane to induce apoptosis Adverse effects: - Nausea & vomiting Contraindication: - pregnancy (teratogenic)
Prevention & Control
1. When outdoors
  1. Minimize the amount of exposed (uncovered) 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. (See below about wearing insecticide-treated clothing.)
  2. 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 generally are those that contain the chemical DEET (N,N-diethylmetatoluamide).
2. When indoors:
  1. Stay in well-screened or air-conditioned areas.
  2. Keep in mind that sand flies are much smaller than mosquitoes and therefore can get through smaller holes.
  3. Spray areas with an insecticide to kill insects.

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