Leishmaniasis Parasitic Disease - Symptoms Treatment and Prevention
Synopsis: Information regarding Leishmaniasis a parasitic disease found in parts of the tropics, subtropics and southern European regions.1
Author: Disabled World Contact: Disabled World
Main DigestThe disease is classified as a, 'Neglected Tropical Disease (NTD).' Leishmaniasis is caused by infection with Leishmania parasites, which are spread by the bite of phlebotomine sand flies. There are a number of forms of leishmaniasis that affect people. The most common forms include visceral leishmaniasis, which affects several internal organs such as a person's liver, spleen and bone marrow, as well as cutaneous leishmaniasis which causes skin sores.
(Alternative - leishmaniosis) - A disease caused by protozoan parasites of the genus Leishmania and spread by the bite of certain types of sandflies. The disease can present in three main ways as: cutaneous leishmaniasis, mucocutaneous leishmaniasis and visceral leishmaniasis. The cutaneous form presents with skin ulcers, while the mucocutaneous form presents with ulcers of the skin, mouth and nose and the visceral form starts with skin ulcers and then later presents with fever, low red blood cells, and a large spleen and liver.
Leishmaniasis is found in more than 90 countries. The ecological setting range from deserts to rain forests. Leishmaniasis is usually more common in rural instead of urban areas, yet it is found in the outskirts of some cities. Climate and additional environmental changes have the potential to expand the geographic range of the sand fly vectors and areas in the world where the disease is found. Leishmaniasis is found on every continent with the exceptions of Antarctica and Australia.
In the Eastern Hemisphere, leishmaniasis is found in some parts of the Middle East, Asia, Africa - especially in the tropical regain and North Africa, and southern Europe. In the Western Hemisphere, it is found in Central and South America and Mexico. The disease is not found in Uruguay or Chile. Occasional instances of cutaneous leishmaniasis have been experienced by people in the states of Oklahoma and Texas in the United States.
The exact number of new instances each year is not known. For cutaneous leishmaniasis, estimates of the number of instances range from around 700,000 to 1,200,000 people affected. For visceral leishmaniasis, estimates of the number of instances range from around 200,000 to 400,000. The instances of leishmaniasis evaluated in America reflect immigration and travel patterns. For example; a number of the instances of cutaneous leishmaniasis in American civilian travelers have been acquired in common tourist destinations such as Costa Rica or other Latin American destinations.
Overall, infection in people is caused by more than 20 species of leishmania parasites that are spread by 30 or so species of phlebotomine sand flies. Specific species of the parasite are spread by particular sand flies. The sand fly vectors are usually most active during twilight, evening and night hours.
In several geographic areas where leishmaniasis is found in people, infected people are not needed in order to maintain the transmission cycle of the parasite. Infected animals such as dogs or rodents, along with sand flies, maintain the transmission cycle. In some parts of the world today, people who are infected with the disease are needed to maintain the cycle however. The type of transmission involved, human-to-sand fly-to human is called, 'anthroponotic.' In areas with anthroponotic transmission, treatment of people may help to control the spread of the parasite.
Chart presenting symptoms of visceral leishmaniasis
Signs and Symptoms of Leishmaniasis
Many different forms of leishmaniasis exist that affect people. Some people have a, 'silent infection,' which means they do not experience any signs or symptoms. The most common form is cutaneous leishmaniasis which causes skin sores. The sores usually develop within a few weeks or months after a person is bitten by a sand fly. The sores may change in appearance or size over a period of time. The sores might begin as, 'papules,' or nodules and end up as ulcers. Skin ulcers may be covered by a crust or scab. The sores are usually painless, but they may also be painful. Some people experience swollen glands near the sores, such as under the arm.
The other main form of the disease is visceral leishmaniasis, which affects several of a person's internal organs such as their liver, spleen and bone marrow. Visceral leishmaniasis may be life-threatening. The illness usually develops within months or even years of a sand fly bite. People who are affected usually experience:
- Weight loss
- Low platelet count
- Low red blood cell count
- Low white blood cell count
- Enlargement of the spleen and liver
Mucosal leishmaniasis is a less common form of leishmaniasis. Mucosal leishmaniasis may be a consequence of infection with some of the species of the parasite that cause cutaneous leishmaniasis in parts of Latin America. Certain types of the parasite may spread from a person's skin and cause sores in their mucous membranes of their nose, throat or mouth.
Various laboratory methods may be used in order to diagnose leishmaniasis, both to detect the parasite and to identify the species. Some of the methods are only available through reference laboratories. Tissue specimens, such as ones taken from a person's skin sores for cutaneous leishmaniasis, or from a person's bone marrow for visceral leishmaniasis, may be examined for the parasite under a microscope, in cultures, or other ways. Blood tests that detect antibody to the parasite may be useful for instances of visceral leishmaniasis. Tests to look for the parasite itself are also usually done.
The first step, even before considering treatment, is to make sure the diagnosis is correct. A person's treatment decisions should be individualized. Health care providers might consult others about the merits of different treatment approaches. Some of the factors to consider include the form of leishmaniasis, the species that caused it, the potential severity, as well as the person's overall health.
The skin sores associated with cutaneous leishmaniasis often times heal on their own, even if the person does not receive any treatment. Waiting for the sores to heal on their own might take months or even years and the sores can leave scars. Another concern applies to some, yet not all, types of the parasite found in parts of Latin America. Certain types may spread from a person's skin and cause sores in their mucous membranes in their nose, throat, or mouth. Mucosal leishmaniasis may not be noticed until years after the original sores have healed. The best way to prevent mucosal leishmaniasis is to receive appropriate treatment of the cutaneous infection. Where visceral leishmaniasis is concerned, if it is not treated - severe instances are typically fatal.
Preventing and Controlling Leishmaniasis
There are no drugs or vaccines available to prevent leishmaniasis infection. The best way for people to prevent an infection is to protect themselves from sand fly bites. To lower the risk of being bitten, people can follow some preventive measures including:
Avoid outdoor activities, particularly from dusk to dawn when sand flies are usually most active. When you are outside, minimize the amount of skin you expose. Wear long-sleeved shirts, socks and long pants. Tuck your shirt into your pants. Apply insect repellent to skin that is exposed and under the ends of your sleeves and pant legs. The most effective repellents usually contain the chemical, 'DEET.' Repellents, bed nets and insecticides are items you should buy before you travel and can be found in camping, hardware and military surplus stores. Bed nets and clothes that have already been treated with a pyrethroid-containing insecticide are also available.
When you are inside stay in air-conditioned or well-screened areas. Bear in mind that sand flies are far smaller than mosquitoes and can get through smaller holes. Spray your living and 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 you can, use a bed net that has been sprayed or soaked with a pyrethroid-containing insecticide. The same treatment may be applied to curtains, screens, clothes and sheets.
World Health Organization - Leishmaniasis
Stanford University - Visceral Leishmaniasis
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