Kala azar/ Leishmaniasis
Kala-azar is a slow progressing indigenous disease caused by a protozoan parasite of the genus Leishmania. In India Leishmania donovani is the only parasite that causes this disease. The parasite primarily infects the reticulo endothelial system and may be found in abundance in bone marrow, spleen and liver.
Kala-azar is a debilitating disease and often fatal if left untreated. Over 147 million people in the South-East Asia Region are at the risk of getting affected with Kala-azar, wherein the poor people living in remote areas are mostly prone to this disease. In India, the disease is prevalent in eastern states namely Bihar, Jharkhand, West Bengal and Uttar Pradesh causing 20 deaths and 13,827 infected cases in 2013(Source: Directorate of National Vector Borne Disease Control Programme)
Health Ministers from Bangladesh, Bhutan, India, Nepal and Thailand have signed a Memorandum of Understanding (MoU) with aim to eliminate Visceral Leishmaniasis (Kala-azar) from their countries on 9 September,2014 at WHO regional conference.
The target of elimination is to achieve less than one Kala-azar case per 10,000 of population annually, at the district or sub-district level, so that it is no longer a public health problem. The elimination strategy of Kala-azar will include early diagnosis and treatment, vector surveillance and integrated vector management with the prime focus on improvement of the environment, social mobilization, research and networking.
A DNA vaccine has been developed by the scientists to fight against Kala-azar. The research is still going on to develop a vaccine which can help in prevention of this disease.
Post Kala-azar Dermal Leishmaniasis (PKDL) is a condition when Leishmania donovani invades skin cells, resides and develops there and manifests as dermal lesions. Some of the kala-azar cases manifests PKDL after a few years of treatment. Recently it is believed that PKDL may appear without passing through visceral stage. However, adequate data is yet to be generated on course of PKDL manifestation.
Symptoms
Recurrent fever intermittent or remittent with often double rise of temperature.
Loss of appetite, pallor and weight loss with progressive emaciation
Weakness
Skin - Dry, thin and scaly and hair may be lost. Light colored person show grayish discoloration of the skin of hands, feet, abdomen and face which gives the Indian name Kala-azar meaning "Black fever".
Anemia - develops rapidly
Causes
There is only one sand fly vector of Kala-azar in India Phlebotomus aregentipes. Sand flies are small insects, about one fourth of a mosquito. The length of a sand fly body ranges from 1.5 to 3.5 mm.
Sand flies breed in high relative humidity, warm temperature, high subsoil water and abundance of vegetation.
These are ecologically sensitive insects, fragile and cannot withstand desiccation.
Diagnosis
Symptomatic:
A case of fever of more than 2 weeks duration not responding to antimalarials and antibiotics. Clinical laboratory findings may include anemia, progressive leucopenia thrombocytopenia.
Laboratory:
Serology tests: A variety of tests are available for diagnosis of Kala-azar. The most commonly used tests based on relative sensitivity; specificity and operational feasibility include Direct Agglutination Test (DAT), rk39 dipstick and ELISA. However all these tests detect IgG antibodies that are relatively long lasting. Aldehyde Test is commonly used but it is a non-specific test. IgM detecting tests are under development and not available for field use.
Parasite demonstration in bone marrow/spleen/lymph node aspiration or in culture medium is the confirmatory diagnosis. However, sensitivity varies with the organ selected for aspiration. Though spleen aspiration has the highest sensitivity and specificity (considered gold standard) but a skilled professional with appropriate precautions can perform it only at a good hospital facility.
This is just an indicative information. For diagnosis and treatment you should consult your doctor.
Treatments
Some of the drugs available for kala-azar in India:
Sodium Stibogluconate
Pentamidine Isethionate
Amphotericin B
Liposomal Amphotericin B
Miltefosine
This is just an indicative information. For diagnosis and treatment you should consult your doctor.
Preventions
No vaccines or drugs to prevent infection are available. The best way for travelers to prevent infection is to protect themselves from sand fly bites. To decrease the risk of being bitten, follow these preventive measures:
Avoid outdoor activities, especially from dusk to dawn, when sand flies generally are the most active.
References:
CDC
WHO
