Black fever or 'Kala-Azar' reported In 11 districts of West Bengal

In the last couple of weeks, as many as eleven districts of West Bengal, mostly in the northern part of the state, have reported at least 65 cases of black fever, also known as 'kala-azar', a senior official of the health department said citing results of state-administered surveillance.

Districts where a maximum number of cases were recorded include Darjeeling, Malda, Uttar Dinajpur, Dakshin Dinajpur, and Kalimpong.

The districts of Birbhum, Bankura, Purulia, and Murshidabad have also reported a few cases of black fever, mainly transmitted by bites of sandflies infected with the parasite Leishmania donovani. No case was detected in Kolkata thus far.

Visceral leishmaniasis (VL), also known as kala-azar is a fatal disease, if left untreated in over 95% of cases.

According to World Health Organisation (WHO), it is characterized by irregular bouts of fever, weight loss, enlargement of the spleen and liver, and anaemia. Most cases of kala-azar occur in Brazil, East Africa and in India.

VL remains one of the top parasitic diseases with outbreak and mortality potential.

It is caused by protozoan parasites which are transmitted by the bite of infected female phlebotomine sandflies.

The disease affects some of the poorest people and is associated with malnutrition, population displacement, poor housing, a weak immune system and lack of financial resources.

Leishmaniasis is also linked to environmental changes such as deforestation, building of dams, irrigation schemes and urbanization.

Kala-azar was practically eradicated from West Bengal. Recent surveillance, however, led to the detection of 65 cases in 11 districts.

According to the official, it was found that the disease was most prevalent in people who have spent a considerable amount of time in Bihar, Jharkhand, and Uttar Pradesh.