Visceral leishmaniasis (VL) is a systemic protozoan disease that is transmitted by phlebotomine sandflies. Poor and neglected populations in East Africa and the Indian sub-continent are particularly affected. Early and accurate diagnosis and treatment remain key components of VL control.
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What is visceral leishmaniasis?
Visceral leishmaniasis (VL), is a vector-borne disease caused by replication of parasites in macrophages, mononuclear phagocytic system. It is caused by the Leishmania donovanicomplex, which includes L. donovaniand L. infantum. It is endemic in large areas of the tropics, subtropics and the Mediterranean Basin.
Which tests are used in the diagnosis of Indian visceral leishmaniasis?
Sundar S, Singh RK, Maurya R, Kumar B, Chhabra A, Singh V, et al. Serological diagnosis of Indian visceral leishmaniasis: direct agglutination test versus rK39 strip test. Trans R Soc Trop Med Hyg. 2006;100:533–7.
What is the diagnostic criteria for leishmaniasis?
Parasitological diagnosis remains the gold standard in the diagnosis of leishmaniasis because of its high specificity.8The amastigote forms (called LD bodies) can be seen in tissue smears from lymph nodes, bone marrow or spleen.
What is the role of ln-PCR in the diagnosis of leishmaniasis?
A nested polymerase chain reaction (Ln-PCR) for diagnosing and monitoring Leishmania infantuminfection in patients co-infected with human immunodeficiency virus. Trans R Soc Trop Med Hyg. 2002;96(Suppl 1):S185–9. [PubMed] [Google Scholar] 43.
How is visceral leishmaniasis diagnosis?
Leishmaniasis is diagnosed by detecting Leishmania parasites (or DNA) in tissue specimens—such as from skin lesions, for cutaneous leishmaniasis (see instructions), or from bone marrow, for visceral leishmaniasis (see note below)—via light-microscopic examination of stained slides, molecular methods, and specialized ...
What are the control of leishmaniasis?
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.
What is the diagnostic stage of leishmaniasis?
Diagnostic Findings In the human host, only the amastigotes stage is seen upon microscopic examination of tissue specimens. Amastigotes can be visualized with both Giemsa and hematoxylin and eosin (H&E) stains. The amastigotes of Leishmania spp.
What tools are used to diagnose a Leishmania infection?
PCR on blood and bone marrow samples is a highly sensitive method for detecting Leishmania.
What causes visceral leishmaniasis?
Visceral leishmaniasis, the most severe form of leishmaniasis also known as kala-azar, is a life-threatening disease caused by Leishmania parasites which are transmitted by female sandflies. Visceral leishmaniasis causes fever, weight loss, spleen and liver enlargement, and, if not treated, death.
How do you control sand flies?
Measures used to control adult sandflies (Lutzomyia and Phlebotomus) include the use of insecticides (mostly pyrethroids) for residual spraying of dwellings and animal shelters, space-spraying, insecticide-treated nets, impregnated dog-collars and personal protection through application of repellents/insecticides to ...
What is laboratory diagnosis of leishmaniasis?
Laboratory diagnosis of leishmaniasis can be made by the following: (i) demonstration of parasite in tissues of relevance by light microscopic examination of the stained specimen, in vitro culture, or animal inoculation; (ii) detection of parasite DNA in tissue samples; or (iii) immunodiagnosis by detection of parasite ...
Which type of tests are used for diagnosis of visceral leishmaniasis?
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.
What laboratory test should be performed to make a diagnosis of visceral leishmaniasis?
This PCR-ELISA technique can potentially be used for diagnosis of VL from peripheral blood samples (44). PCR done from blood spots on filter paper can also be used as a screening test to identify Leishmania infection in immunocompromised patients with high parasite loads in peripheral blood.
What is the best protocol for detection of asymptomatic Leishmania donovani infection?
Tests which detect active infection, such as quantitative real-time polymerase chain reaction (qPCR), loop-mediated isothermal amplification (LAMP), or Leishmania antigen ELISA, could be used as tools to monitor active asymptomatic infection and quickly identify areas with increasing active transmission.
What is used in treatment of kala-azar?
The aim of treatment in kala-azar is killing of the parasite with effective drugs which are cheap and less toxic. Pentavalent antimonials are the first line drugs and pentamidine and amphotericin B are the second line drugs. Recently the latter are being used as first line drugs also [12].
What is the drug of choice for treatment of leishmaniasis?
Sodium stibogluconate (Pentostam) Sodium stibogluconate has been the drug of choice for the treatment of cutaneous and mucocutaneous leishmaniasis in the United States. This agent is also effective against visceral leishmaniasis and is often the first-line treatment outside the United States.
How do you prevent leishmaniasis in dogs?
Repellent collars: the most simple and effective way Without a doubt, the best strategy for the prevention of leishmaniasis is the use of quality repellent collars. One simple act can make all the difference. The use of a good collar protects our dog from sand fly bites for several months.
Is there a vaccine for leishmaniasis?
Currently there are no available vaccines against any form of human leishmaniasis. Unlike most parasitic infections, patients who recover from leishmaniasis naturally or following drug treatment develop immunity against reinfection indicating that the development of an effective vaccine should be feasible6,7,8.
What is used in treatment of kala-azar?
The aim of treatment in kala-azar is killing of the parasite with effective drugs which are cheap and less toxic. Pentavalent antimonials are the first line drugs and pentamidine and amphotericin B are the second line drugs. Recently the latter are being used as first line drugs also [12].
What are the factors that contribute to the elimination of visceral leishmaniasis?
Several factors are thought to favour the elimination of visceral leishmaniasis in the Indian subcontinent: the disease in this area is anthroponotic, with humans being the only reservoir and Phlebotomous argentipes sandflies the only known vector; new and more effective drugs (such as miltefosine) and a rapid diagnostic test, the rk39 immunochromatographic test, are available that can be used in the field; there is strong political commitment and inter-country collaboration; and the disease is endemic in only a limited number of districts. The elimination initiative has adopted five main strategies:
What is cutaneous leishmaniasis?
In cutaneous leishmaniasis, the patient generally presents with one or several ulcer (s) or nodule (s) in the skin. Different species of Leishmania can infect the macrophages in the dermis, with variable clinical presentations and prognoses 3, 4.
What is the cause of VL?
As already mentioned, VL is caused by two leishmanial species, L. donovani or L. infantum, depending on the geographical area. L. infantum infects mostly children and immunosuppressed individuals, whereas L. donovani infects all age groups.
Why are confirmatory tests required for VL?
As the clinical presentation of VL lacks specificity, confirmatory tests are required to decide which patients should be treated. Such tests should be highly sensitive (>95%) as VL is a fatal condition, but also highly specific because the current drugs used to treat VL are toxic. Ideally, a test should be able to make the distinction between acute disease and asymptomatic infection, because none of the drugs currently available is safe enough to treat aymptomatic infections. Moreover, such tests should be simple and affordable.
What is PKDL rash?
PKDL is characterized by a macular, maculo-papular or nodular rash and is a complication of VL that is frequently observed after treatment in Sudan and more rarely in other East African countries and in the Indian subcontinent 8. It can also occur in immunosuppressed individuals in L. infantum -endemic areas.
Why is CMI important?
It is of utmost importance for vaccine development and disease control to understand the factors that might predispose some individuals to develop the disease or control the infection. The host specific cell-mediated immune (CMI) response has an important role in controlling the infection.
How long does it take for a VL to show symptoms?
Following an incubation period that generally lasts between 2 and 6 months, VL patients present symptoms and signs of persistent systemic infection (including fever, fatigue, weakness, loss of appetite and weight loss) and parasitic invasion of the blood and reticulo-endothelial system (that is, the general phagocytic system), such as enlarged lymph nodes, spleen and liver. Fever is usually associated with rigor and chills and can be intermittent. Fatigue and weakness are worsened by anaemia, which is caused by the persistent inflammatory state, hypersplenism (the peripheral destruction of erythrocytes in the enlarged spleen) and sometimes by bleeding.
What are the factors that contribute to the elimination of visceral leishmaniasis?
Several factors are thought to favour the elimination of visceral leishmaniasis in the Indian subcontinent: the disease in this area is anthroponotic, with humans being the only reservoir and Phlebotomous argentipes sandflies the only known vector; new and more effective drugs (such as miltefosine) and a rapid diagnostic test, the rk39 immunochromatographic test, are available that can be used in the field; there is strong political commitment and inter-country collaboration; and the disease is endemic in only a limited number of districts. The elimination initiative has adopted five main strategies:
Why are confirmatory tests required for VL?
As the clinical presentation of VL lacks specificity, confirmatory tests are required to decide which patients should be treated. Such tests should be highly sensitive (>95%) as VL is a fatal condition, but also highly specific because the current drugs used to treat VL are toxic. Ideally, a test should be able to make the distinction between acute disease and asymptomatic infection, because none of the drugs currently available is safe enough to treat aymptomatic infections. Moreover, such tests should be simple and affordable.
What is the current control strategy for VL?
The current control strategies for VL rely on reservoir and vector control, the use of insecticide-impregnated materials and active case detection and treatment 14, 42; anti-leishmanial vaccines are still being developed .
How long does it take for a VL to show symptoms?
Following an incubation period that generally lasts between 2 and 6 months, VL patients present symptoms and signs of persistent systemic infection (including fever, fatigue, weakness, loss of appetite and weight loss) and parasitic invasion of the blood and reticulo-endothelial system (that is, the general phagocytic system), such as enlarged lymph nodes, spleen and liver. Fever is usually associated with rigor and chills and can be intermittent. Fatigue and weakness are worsened by anaemia, which is caused by the persistent inflammatory state, hypersplenism (the peripheral destruction of erythrocytes in the enlarged spleen) and sometimes by bleeding.
What is VL in phlebotomy?
Visceral leishmaniasis (VL) is a systemic protozoan disease that is transmitted by phlebotomine sandflies. Poor and neglected populations in East Africa and the Indian sub-continent are particularly affected. Early and accurate diagnosis and treatment remain key components of VL control. In addition to improved diagnostic tests, accurate and simple tests are needed to identify treatment failures. Miltefosine, paromomycin and liposomal amphotericin B are gradually replacing pentavalent antimonials and conventional amphotericin B as the preferred treatments in some regions, but in other areas these drugs are still being evaluated in both mono- and combination therapies. New diagnostic tools and new treatment strategies will only have an impact if they are made widely available to patients.
What is the cause of VL?
As already mentioned, VL is caused by two leishmanial species, L. donovani or L. infantum, depending on the geographical area. L. infantum infects mostly children and immunosuppressed individuals, whereas L. donovani infects all age groups.
What is the most important tropical disease?
... Leishmaniasis is a group of vector-borne tropical diseases considered to be one of the most epidemiologically important as it affects approximately 2 million people per year [1,2]. Leishmaniasis is caused by Leishmania parasites, a genus of kinetoplastids that exhibit two different stages during their life cycle: the promastigote stage adapted to survive in the gut of phlebotomine sandfly vectors, and the amastigote stage, evolutionarily adapted to survive inside the vertebrate host's macrophages [3]. ...
What is VL in phlebotomy?
Visceral leishmaniasis (VL) is a systemic protozoan disease that is transmitted by phlebotomine sandflies. Poor and neglected populations in East Africa and the Indian sub-continent are particularly affected. Early and accurate diagnosis and treatment remain key components of VL control. In addition to improved diagnostic tests, accurate and simple tests are needed to identify treatment failures. Miltefosine, paromomycin and liposomal amphotericin B are gradually replacing pentavalent antimonials and conventional amphotericin B as the preferred treatments in some regions, but in other areas these drugs are still being evaluated in both mono- and combination therapies. New diagnostic tools and new treatment strategies will only have an impact if they are made widely available to patients.