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West Nile Virus


The West Nile virus was found in two people, one in Brooklyn and one in Queens, as well as a “record number” of infected mosquitoes throughout the city, according to the New York City Health Department.


GS Paper 2: Health

Mains Question

Virus attacks are common in various parts of the world, but we also see a sluggish attitude of governments and the WHO. Analyze the strategic planning of international stakeholders in the case of health. (150 Words)

The Scene

  • It was yet another potential health threat for tired New Yorkers to be concerned about after a summer filled with other virus threats, such as a new, highly infectious COVID-19 variant that overlapped with a monkeypox outbreak and the discovery this month that polio was circulating in the city’s sewage.
  • The West Nile virus was detected in two people, one in Brooklyn and one in Queens, as well as a “record number” of infected mosquitoes throughout the city, according to the New York City Health Department on Tuesday.
  • According to the health department’s announcement, 54 cases and four deaths have been reported across the country this year.
  • According to the health department, the number of mosquito pools that tested positive for West Nile virus in New York is the “highest number ever recorded,” at 1,068 across the five boroughs, up from 779 this time last year.
  • According to the department, the city detected its first case of West Nile virus in 1999, and over the last decade, as few as six to as many as 30 people have tested positive annually, with a death rate of about 14%. The first of this year’s two cases was discovered at the end of last week.

Why are there so many West Nile virus-infected mosquitos in New York City?

  • A department spokesperson stated that higher-than-average temperatures are a factor. The larvae are maturing into adults at a faster rate.
  • To prevent the spread of West Nile virus in the city, the health department intends to reduce the mosquito population by applying larvicide to breeding areas, such as standing water around street sewer grates and salt marshes.
  • So far this season, multiple larviciding events have been conducted, all 150,000 catchbasins have been treated, and two spray events per week are currently being conducted to control adult mosquitos where surveillance indicates WNV-positive. Mosquitoes have reached a level that may have an impact on public health.


  • WNV was discovered in a woman in Uganda’s West Nile district in 1937.
  • In 1953, it was discovered in birds in the Nile delta region. WNV was not considered pathogenic to birds prior to 1997.
  • WNV-related human infections have been reported in many countries for over 50 years.


  • WNV is an infectious disease that is spread by infected mosquitos. The bite of an infected Culex mosquito transmits it from birds to humans. In humans, it can cause a fatal neurological disease.
  • According to the World Health Organization, the virus causes West Nile fever in approximately 20% of cases (WHO). It shares similarities with the Zika, Dengue, and Yellow Fever viruses.
  • According to the CDC, birds are the primary host of the virus, and mosquitoes become infected by biting birds.
  • According to health officials, it cannot be passed from person to person through casual contact.

What are the signs and symptoms of West Nile virus?

  • According to the Centers for Disease Control and Prevention, most people infected with West Nile virus experience no symptoms or only mild to moderate illness.
  • According to the CDC, approximately one in every five people develop a fever, along with other symptoms such as headaches, body aches, joint pains, diarrhoea, vomiting, or a rash.
  • And about one in every 150 infected people develops severe illness affecting the central nervous system. High fever, headaches, neck stiffness, disorientation, coma, vision loss, or paralysis are all symptoms.
  • According to health officials, those over the age of 60 are at the greatest risk of severe illness. In New York City, the median age of people with positive cases is 62. People who have certain medical conditions, such as cancer, diabetes, or high blood pressure, are also at a higher risk of severe illness.
  • Recovery from a severe West Nile infection can take several weeks to months, but central nervous system damage can be permanent.
  • A West Nile infection can be detected through a blood test.
  • There are no vaccines or medications available to treat West Nile virus infections. Some symptoms can be relieved with over-the-counter pain relievers, but hospitalisation may be required in more severe cases.

Global Prevalence

  • WNV outbreak sites can be found along all major bird migration routes.
  • The virus is most commonly found in Africa, Europe, the Middle East, North America, and West Asia.
  • In most countries, WNV infections peak during the period when mosquito vectors are most active and the ambient temperature is high enough for virus multiplication.

India’s prevalence:

  • Human antibodies against WNV were first discovered in 1952 in Mumbai.
  • The virus’s activity has since been reported in southern, central, and western India.
  • WNV was isolated from Culex vishnui mosquitos in Andhra Pradesh and Tamil Nadu.
  • It was isolated from Culex quinquefasciatus mosquitos in Maharashtra.
  • It has been isolated from humans in Karnataka.
  • Human serum from Tamil Nadu, Karnataka, Andhra Pradesh, Maharashtra, Gujarat, Madhya Pradesh, Odisha, Rajasthan, and Assam also contained WNV neutralising antibodies.
  • Serologically confirmed cases of WNV infection were reported in Vellore and Kolar districts in 1977, 1978, and 1981, respectively, and in West Bengal in 2017.
  • In 2013, the complete genome sequence of WNV was isolated during an acute encephalitis outbreak in Kerala.
  • The link between WNV and eye infection was clearly established in Tamil Nadu during an epidemic of mysterious fever in the first half of 2010.
How to Protect Yourself Against the West Nile Virus?
  • The New York City Health Department recommends using picaridin-containing insect repellents that can be applied directly to skin and clothing. The Environmental Protection Agency in the United States also has a list of recommended repellents.
  • Because mosquitoes are most active from April to October, limiting outdoor activities during those months, especially at dawn and dusk, can help reduce the risk of contracting the virus.
  • Health officials advise wearing protective clothing outside in the evenings. During the day, they advise against wearing dark clothing, sitting in shaded areas where mosquitoes lay eggs, and wearing perfumes, colognes, or scented body lotions.
  • People are also encouraged to report to 311 areas with standing water where West Nile virus-carrying mosquitos can breed.

Measures of Prevention

  • Preventive measures should include the establishment of an active animal health surveillance system to detect new cases in birds and horses.
  • Because WNV outbreaks in animals precede human cases, early warning for veterinary and human public health authorities is essential.
  • The European Centre for Disease Control and Prevention (ECDC) has proposed that the European Union implement 28-day blood donor deferral or nucleic acid testing of prospective donors who have visited or lived in an affected area (EU).
  • Furthermore, donors of organs, tissues, and cells who live in or return from an affected area must be tested for WNV infection.

July 2024