Prelims 2021 Prelims cum Mains Science & Tech

How kala-azar was eliminated from a highly endemic district in Bihar

In News

  • As per a recent paper published in PLOS Neglected Tropical Diseases, Kala Azar disease has been eliminated from Vaishali, a district in Bihar where the disease is highly endemic.
  • Note: A disease is considered to be eliminated when the annual cases of the disease are reduced to less than 1 case per 10,000 people at the sub-district or block level. Eradication of the disease would mean that there are zero cases.

About: Kala Azar or visceral leishmaniasis (VL)

  • Kala-azar or visceral leishmaniasis (VL) is a parasitic disease of the viscera (the internal organs, particularly the liver, spleen, bone marrow and lymph nodes).
  • The term kala-azar comes from India where it is the Hindi for black fever. The disease is also known as Indian leishmaniasis, visceral leishmaniasis, leishmania infection, dumdum fever, black sickness, and black fever.
  • It is caused by a protozoan Leishmania parasite and is transmitted to humans by the bite of infected female sandflies.
  • On average, the sand flies that transmit the parasite are only about one fourth the size of mosquitoes or even smaller.

Signs and symptoms:

  • Some people have a silent infection, without any symptoms or signs.
  • People who develop symptoms of infection usually have fever, weight loss, enlargement (swelling) of the spleen and liver.
  • People may have low blood counts, including a low red blood cell count, a low white blood cell count, and a low platelet count.
  • Without proper diagnosis and treatment, the disease is associated with high fatality (deaths).

Incidence of the disease:

  • According to the World Health Organisation (WHO), globally, about 7 to 10 lakh new cases occur annually.
  • India accounts for about two-thirds of the total global cases, and the disease is endemic to Bihar, Jharkhand, Uttar Pradesh and West Bengal.
  • More than 90% of the global burden of visceral leishmaniasis (VL) was contributed by seven countries in 2015: Brazil, Ethiopia, India, Kenya, Somalia, South Sudan and Sudan
  • An initiative was launched by WHO to eliminate VL as a public health problem from the South East Asia region by 2020. The deadline has now been extended to 2023.

Parasitic infections in Humans:

  • A parasite is an organism that lives in another organism, called the host, and often harms it. It depends on its host for survival.
  • Protozoa is one of the three main classes of parasites that can cause disease in humans.
    • Protozoa are microscopic, one-celled organisms.
    • They are able to multiply in humans, which contributes to their survival and also leads to serious infections.
  • Transmission of protozoa that live in a human’s intestine to another human typically occurs through a faecal-oral route (for example, contaminated food or water or person-to-person contact).
  • Protozoa that live in the blood or tissue of humans are transmitted to other humans by a vector (for example, through the bite of a mosquito or sand fly).

News Summary:

  • India accounts for about two-thirds of the total global cases of Kala-azar or Visceral leishmaniasis (VL), and the disease is endemic to Bihar, Jharkhand, Uttar Pradesh and West Bengal.
  • An initiative was launched by WHO to eliminate the disease as a public health problem from the South East Asia region by 2020 (later extended to 2023).
  • In a recent paper, a team from RMRI Patna (an institute of ICMR) published the success story of how their efforts helped eliminated the disease from Vaishali, a district in Bihar where the disease is highly endemic.
  • The team also implemented its strategy in other districts of Bihar where the disease is highly endemic, namely Saran and Siwan, which led to about 48% reduction in cases within a year.

Details of the elimination programme in Vaishali:

  • With an area of around 2,000 square kilometres, Vaishali has a population of over 35 lakh and about 22% in the district got affected by Kala-azar or visceral leishmaniasis (VL) each year.
  • The RMRI programme included mapping of the case distribution, early case detection and chemical-based vector control. 
  • Once a person is diagnosed with Kala-azar, indoor chemical spraying is done at the patient’s house and at the neighbouring houses within 500 metres.
    • Though the disease is not contagious, the infected sand fly may be present in the area and the chemical spray will help kill them.
  • Hospital staff and medical doctors in the region were trained and nearly 2,500 ASHA workers and 1,000 field workers were also trained.
  • The team also carried out community awareness campaigns.

Way ahead:

  • A strong supervision and monitoring system is required to ensure continued success, and to move towards complete eradication.
  • Frequent monitoring of active cases – track, test, and treat strategy – in the hotspot region is very important.
  • Routine monitoring is needed to identify if the Kala-azar vector (sandfly) has developed resistance to insecticides.

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