Saturday, March 16, 2019

West Nile virus: Another impending outbreak in India?

Health Ministry takes stock of the public health measures for controlling West Nile Virus 

A section of the media has reported that a seven year old boy from Malappuram District of Kerala is suffering from a West Nile Virus (WNV), a mosquito-borne disease, mostly reported in the continental United States.

Union Minister of Health and Family Welfare is closely monitoring the situation and has spoken to the State Health Minister of Kerala in this regard. He has directed for all support to be extended to Kerala in its prevention and management.

Secretary (HFW) held a meeting with Additional Chief Secretary Shri Rajeev Sadanandan, Kerala and reviewed the situation. The Health Ministry has dispatched a multi-disciplinary Central team from National Centre for Disease Control (NCDC). The Central team includes Dr. Ruchi Jain, RHO Trivandrum, Dr Suneet Kaur, Assitant Director, NCDC, Dr E Rajendran, Entomologist, NCDC, Calicut and Dr Binoy Basu, EIS Officer, NCDC. The team will support the State Health Authorities in managing the disease.

The Indian Council of Medical Research (ICMR) has also been alerted and a close watch is being maintained at Central and State level.  There are no reports available so far for spread of this virus in other parts of the country… (Press Information Bureau, Ministry of Health and Family Welfare, March 14, 2019)

Facts about West Nile Virus

·         West Nile Virus is a member of the flavivirus genus and belongs to the Japanese encephalitis antigenic complex of the family Flaviviridae.

·         The virus was first isolated in a woman in the West Nile district of Uganda in 1937.

·         It is commonly found in Africa, Europe, the Middle East, North America and West Asia.

·         Presence of WNV was documented in north- eastern region of India during the year 2006 from four districts (Japanese encephalitis (JE) endemic areas) of Assam; in which 11.6% of serum samples of AES (acute encephalitis syndrome) cases were found positive for IgM against WNV (these samples were negative for IgM against JE virus). During an outbreak of AES in Kerala, in May 2011, presence of WNV was confirmed in clinical specimens. Since then, WNV encephalitis cases have regularly been reported in Kerala (National Health Portal of India).  

·         The virus is maintained in nature in a cycle involving transmission between birds and mosquitoes. Humans, horses and other mammals can be infected.

·         Transmission: Humans acquire the infection through the bites from infected mosquitoes. The virus may also be transmitted through contact with other infected animals, their blood, or other tissues. Transmission may also occur through organ transplant, blood transfusions and breast milk. There is one reported case of transplacental (mother-to-child) WNV transmission. To date, no human-to-human transmission of WNV through casual contact has been documented.

·         Incubation period: 3-14 days.

·         Clinical features: West Nile virus infection may mimic either dengue or chikungunya like illness.
o    The infection is asymptomatic in 80% of infected persons; in some cases, the infection may lead to West Nile fever or severe West Nile disease (also called neuroinvasive disease, such as West Nile encephalitis or meningitis or West Nile poliomyelitis).
o    Symptoms of West Nile fever include fever, headache, tiredness, body aches, nausea, vomiting, skin rash on the trunk of the body (occasionally) and swollen lymph glands. Most people recover completely, but fatigue and weakness can last for weeks or months
o    Symptoms of severe disease include headache, high fever, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, and paralysis. Recovery might take several weeks or months. It is potentially fatal.

  • Diagnosis is by detection of IgM antibodies in CSF and serum specimens via IgM antibody capture ELISA, neutralisation assays, viral detection by RT-PCR assay, and virus isolation by cell culture. Serum IgM antibody may persist for more than a year.

  • Treatment is supportive for patients with severe infection which involves hospitalization, intravenous fluids, respiratory support, and prevention of secondary infections.

  • There is no vaccine available for humans.

  • Prevention: The most effective way to prevent infection is to prevent mosquito bites. Use insect repellent, wear long-sleeved shirts and pants, treat clothing and gear and take steps to control mosquitoes indoors and outdoors.

Dr KK Aggarwal
Padma Shri Awardee
President Elect Confederation of Medical Associations in Asia and Oceania   (CMAAO)
Group Editor-in-Chief IJCP Publications
President Heart Care Foundation of India
Past National President IMA

No comments:

Post a Comment