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What is leishmaniasis? Leishmaniasis is a parasitic disease that is found in Afghanistan, 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).
What is Leishmaniasis? • Where in world is it found? • What are the signs and symptoms of • A. cutaneous B. visceral • How do people get infected? • Who is at risk for infection? • Treatment • Prevention
What is 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 • cutaneousleishmaniasis, which causes skin sores, • visceral leishmaniasis, which affects several internal organs (usually spleen, liver, and bone marrow).
Where in world is leishmaniasis found? • Leishmaniasis is found in some parts of Asia, the Middle East, Africa, and southern Europe. • found in specific areas of about 88 countries. Some countries account for most of the world’s cases; • CutaneousLeishmaniasis - over 90 percent of the cases of occur in parts of Afghanistan, Algeria, Iran, Iraq, Saudi Arabia, and Syria (in the Old World) and in Brazil and Peru (in the New World); • world's largest incidence of cutaneousleishmaniasis, with an estimated 250 000 cases annually in Afghanistan • Visceral Leishmaniasis - over 90 percent of the cases of occur in parts of India, Bangladesh, Nepal, Sudan, and Brazil.
leishmaniasis occurs commonly in Kabul • partly due to bad sanitation and waste left uncollected in streets, • allowing parasite-spreading sand flies a favorable environment • In Kabul, the number of people infected was estimated to be at least 200,000, and in three other towns • Kabul is estimated as the largest center of cutaneous leishmaniasis in the world.
What are the signs and symptoms of cutaneousleishmaniasis? • People with cutaneousLeishmaniasis have one or more sores on their skin. • sores can change in size and appearance over time. • Growth is usually fairly gradual, but continues over a period of months. • The incubation period ranges from a few weeks to several years. • sores may start out as bumps or nodules, and may end up as ulcers (like a volcano, with a raised edge and central crater).
What are the signs and symptoms of cutaneousleishmaniasis? • Some Leishmaniasis ulcers are covered by a scab. In the absence of secondary bacterial infection, the lesions are usually non-painful. • May have swollen glands near the sores (for example, under the arm if the sores are on the arm or hand). • Spontaneous healing is common, but requires months to years.
cutaneousleishmaniasis • Leishmania skin infections may be mild or severe ulcers which eventually heal, provoking solid immunity and leaving the individual resistant to reinfection. • An interesting feature of leishmaniasis is that despite the disappearance of the lesion and resistance to reinfection, residual parasites remain in the host, probably for a very long time, if not forever. • They can be reactivated by trauma, or immunosuppression such as the common reactivating syndrome in AIDS patients.
A man with diffuse skin lesions from Cutaneousleishmaniasis. similar lesions can be observed in leprosy.
What are the signs and symptoms of Visceral Leishmaniasis? • Visceral Leishmaniasis, affects several internal organs (usually spleen, liver, and bone marrow). • 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. • In most disease-endemic areas transmission is from animal to human, with domestic dogs as the main reservoir.
Visceral leishmaniasis (VL), also known as kala-azar, black fever, and Dumdum fever • Is the most severe form of leishmaniasis. • This disease is the second-largest parasitic killer in the world (after malaria), responsible for an estimated 500,000 cases each year worldwide
Visceral Leishmaniasis • Visceral leishmaniasis in Afghanistan: Although several hundreds of cases of visceral leishmaniasis are reported every year from Afghanistan's neighbouring countries (Iran, Pakistan, Turkmenistan and Uzbekistan), there have been only 23 cases reported from Afghanistan since 1980 in the scientific literature. • Unlike cutaneous leishmaniasis, the visceral form is potentially fatal, with case-fatality rates as high as 85%.
Visceral Leishmaniasis Organomegaly = large organs Enlarged liver and spleen
Sometimes mistaken for mosquitoes, thesesandflies are common vectors for various diseases, including leishmaniasis. Female phlebotomine sandfly.
How do people get infected with Leishmania parasites? • The main route 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: • do not make noise when they fly; • are small: they are only about one-third or smaller than typical mosquitoes; • bites might not be noticed (the bites may be painless or painful).
Sandfly • Ask to see if there is a local name for the sandfly • If they have been bitten shortly after sunset or through the night
How do people get infected with Leishmania parasites? • climate restricts the sandfly vector's season in Afghanistan from April to October, • The disease is usually caused by Leishmania donovani or L. infantum, transmitted to human and animal hosts by the bite of phlebotomine sandflies. • Although in most disease-endemic areas transmission is zoonotic, with domestic dogs as the main reservoir
Causal Agent:- obligate intracellular protozoa of the genus Leishmania. - a vector-borne disease that is transmitted by sandflies
How do people get infected with Leishmania parasites? continued • 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. • Some types (species) of Leishmania parasites may also be spread by blood transfusions or contaminated needles (needle sharing).
Who is at risk for Leishmania infection? • People of all ages are at risk for infection if they live or travel where leishmaniasis is found. • Leishmaniasis usually is more common in rural than in urban areas; but it is found in the outskirts of some cities. • transmission risk is highest from dusk to dawn because this is when sand flies generally are the most active. • people who may have an increased risk for infection include soldiers and people who are active outdoors at night/twilight.
Diagnosis • clinically diagnosed cutaneous leishmaniasis (based on the presence or absence of cutaneous leishmaniasis lesions or scars, number of lesions, date of lesion onset) • logistic constraints, parasitologic diagnosis of cutaneous leishmaniasis lesions (i.e., microscopic examination or parasite culture) was not conducted. • skin lesions attributed to causes other than cutaneous leishmaniasis are rare, and experience has shown that clinical diagnosis has a sensitivity and specificity of >80% and >90%, respectively
Diagnosis • Leishmaniasis is diagnosed in the haematology laboratory with preparations of peripheral blood or aspirates from marrow, spleen, lymph nodes or skin lesions. • However, the retrieval of tissue samples is often painful for the patient and it can be difficult to identify the infected cells
Diagnosis cont. • For these reasons, other indirect immunological methods of diagnosis are developed. • Methods include the enzyme-linked immunosorbent assay (ELISA), antigen coated dipsticks, and the direct agglutination test (DAT). • Although these tests are readily available, they are not the standard diagnostic tests due to their insufficient sensitivity and specificity.
Diagnosis • Over the years, several different Polymerase Chain Reaction (PCR) assays have been made for the detection of Leishmania DNA. • With the PCR assay, a specific and sensitive diagnostic procedure is finally possible. • However tests may not be available in certain areas.
Treatment • The treatment of leishmaniasis depends on the form of the disease (cutaneous, mucocutaneous, or visceral), and may be in the form of tablets or injections. • Cutaneous leishmaniasis sometimes heals on its own and may not require treatment. • Leishmaniasis management guidelines in Afghanistan will have to be updated to include available treatment regimens for the visceral form of the disease.
There are two common therapies containing antimony ; meglumine antimoniate and sodium stibogluconate. • not completely understood how these drugs act against the parasite; • in parts of the world the parasite has become resistant to antimony when treating for visceral or mucocutaneous leishmaniasis • level of resistance varies • Amphotericin is now the treatment of choice; its failure in some cases to treat visceral leishmaniasis leishmaniasis
paromomycin reintroduced for treatment of leishmaniasis, • treatment with paromomycin will cost about $10. The drug had originally been identified in 1960s, • had been abandoned because it would not be profitable, as the disease mostly affects poor people. • A 21-day course of paromomycin produces a definitive cure in >90% of patients with visceral leishmaniasis.
What can I do to prevent infection? No vaccines or drugs to prevent infection are available. • best way to prevent infection is to protect themselves from sand fly bites. • To decrease the risk of being bitten: • avoid outdoor activities, especially from dusk to dawn, when sand flies generally are the most active. When outdoors (or in unprotected quarters): • minimize the amount of exposed skin. As tolerable, 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. • most effective repellents are those that contain the chemical DEET (N,N-diethylmetatoluamide).
What can I do to prevent infection?- continued • When indoors: • Stay in well-screened or air-conditioned areas. • 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 an insecticide (permethrin or deltamethrin). • same treatment can be applied to screens, curtains, sheets, and clothing (clothing should be retreated after five washings).
Prevention • cutaneous leishmaniasis has been the historical focus of vaccination attempts, as it has been known since antiquity that individuals who had healed their skin lesions were protected from further infections. • Bedouin traditionally expose their babies' bottoms to sandfly bites in order to protect them from facial lesions. • Another ancient technique practised in the Middle East has been the use of a thorn to transfer infectious material from lesions to uninfected individuals. • To date, there is no vaccine against Leishmania in routine use anywhere in the world. Several vaccine preparations are in more or less advanced stages of testing. • On February 2012, the nonprofit Infectious Disease Research Institute launched the world’s first human clinical trial of the visceral leishmaniasis vaccine.
Preventive vaccines are recognized as the best and most cost-effective protection measure against pathogens and save millions of lives across the globe each year. Leishmania vaccine development has proven to be a difficult and challenging task and is hampered by an inadequate knowledge of disease pathogenesis, the complexity of immune responses needed for protection, and the cost of vaccine development.
