The well being officers of Kerala are on excessive alert after the loss of life of a 47-year-old man from Thrissur as a result of West Nile Virus. However, this isn’t a brand new case. In 2019, a six-year-old boy within the Malappuram district died of the identical an infection. According to experiences, the virus was first reported within the state of Alappuzha in 2006 after which in Ernakulam in 2011.
What is the West Nile Virus and the way does it unfold?
The West Nile Virus is a mosquito-borne, single-stranded RNA virus. According to the World Health Organization (WHO), it’s “a member of the flavivirus genus and belongs to the Japanese Encephalitis antigenic complex of the family Flaviviridae”. The principal vector for transmission of this virus is the Culex species of mosquitoes. It is transmitted by contaminated mosquitoes between and amongst people and animals, together with birds, that are the reservoir host of the virus.
“It is transmitted by mosquitoes in the genus Culex, which also spreads Japanese encephalitis. Birds act both as carriers and amplifying hosts of the West Nile Virus virus in nature. Ornithophilic mosquitoes belonging mainly to Culex species act as vectors for transmission of infection from viraemic birds to a large spectrum of vertebrate hosts. Cx. vishnui complex (India) acts as a major vector of the WN virus. There is no evidence to suggest a person-to-person/animal or animal to animal/ person transmission,” Dr. Monalisa Sahu, Consultant Infectious Diseases, Yashoda Hospitals Hyderabad advised Financial Express.com.
West Nile Virus may also unfold by way of blood transfusion, from an contaminated mom to her baby, or by way of publicity to the virus in laboratories. However, it’s not identified to unfold by contact with contaminated people or animals.
Dr. Sahu additionally maintained that the virus multiplies within the mosquito vector and after an extrinsic incubation interval of about 2 weeks, the vector turns into infective for energetic transmission to a prone host. “Migratory birds play a major role in the WN virus dissemination. However, virus dissemination through infected mosquitoes or by illegally imported infected pet birds should also be considered a possibility,” she added.
According to the US Centre for Disease Control and Prevention (CDC), it doesn’t unfold “through eating infected animals, including birds. Always follow instructions for fully cooking meat”. To date, no human-to-human transmission of WNV by way of informal contact has been documented, says the WHO.
Symptoms of West Nile Virus
According to medical doctors and well being specialists, the illness is asymptomatic in 80 p.c of the contaminated individuals. However, others develop West Nile fever or extreme West Nile illness.
Dr. Sahu knowledgeable that usually the an infection has a light, often-subclinical course. The incubation interval continues from 2 to 14 days (21 days in immunocompromised) and it’s extra widespread in adults and the aged. Meanwhile, the illness can vary from acute febrile sickness to Neuroinvasive illness. She additionally stated that over 50 p.c of the sufferers’ widespread signs embrace: Headache, Generalized weak spot, maculopapular rash, Fever (typically low grade) and Myalgia.
“While signs like Joint ache, Chills, Painful eyes, Vomiting or diarrhoea, Lymphadenopathy, Meningoencephalitis, and CNS involvement happen in lower than 1 p.c of these contaminated by way of mosquito chew are much less widespread. The signs are just like viral meningitis i.e fever, headache, and photophobia. Confusional state to extreme encephalopathy, coma, and loss of life can happen in uncommon circumstances, Dr. Sahu stated.
The CDC has additionally acknowledged that it’s estimated that roughly 1 in 150 individuals contaminated with the West Nile Virus will develop a extra extreme type of illness. Recovery from extreme sickness may take a number of weeks or months. Some results on the central nervous system is likely to be everlasting. It normally turns deadly in individuals with co-morbidities and immuno-compromised individuals (comparable to transplant sufferers).
Detection of West Nile Virus
Reportedly, the virus was first remoted in a lady within the West Nile district of Uganda in 1937. It was recognized in birds (crows and Columbiformes like doves and pigeons) within the Nile delta area in 1953. Before 1997, West Nile Virus was not thought-about pathogenic for birds, however then, a extra virulent pressure prompted the loss of life in Israel of various chicken species, presenting indicators of encephalitis and paralysis.
In 1999, a WMV pressure, believed to be one circulating in Israel and Tunisia, reached New York producing a big outbreak that unfold throughout the United States and ultimately throughout the Americas, from Canada to Venezuela.
“West Nile virus is a virus which has caused large outbreaks of meningoencephalitis ( viral infection affecting the central nervous system) in many parts of the world including New York in 1999 – 2000 and Israel during 1997-2000. It also caused many severe outbreaks in European and African countries in the 1950s and 1970s. It was first isolated in an elderly woman with fever in West Nile district of Uganda(currently Nile province), in 1937, from where it gets its name,” Dr. Sahu knowledgeable.
According to the worldwide well being company, human infections prompted as a result of West Nile virus have been reported in lots of nations on the planet for over 50 years. Today, the virus is discovered generally in Africa, Europe, the Middle East, North America, and West Asia.
“Migratory birds play a major role in the West Nile virus dissemination. However, virus dissemination through infected mosquitoes or by illegally imported infected pet birds should also be considered a possibility,” Dr. Sahu added.
West Nile Virus in India
Dr. Sahu additionally maintained that In India, not like Japanese encephalitis and dengue, there have been no critical outbreaks of West Nile. “Despite the presence of mosquito vectors in abundance, and potentially neurovirulent strains of the virus there have been no serious epidemics due to West Nile virus in India comparable to Japanese Encephalitis outbreaks. The reasons for this situation are not clear, but the presence of other flaviviruses in India could be an important factor in limiting the spread of West Nile Virus or reducing its severity,” She advised Financial Express.com.
She additionally cautioned that there’s an absence of broad utilization of exact diagnostic instruments for West Nile Virus, therefore the magnitude of the illness burden and seriousness of the issue can’t be assessed.
“If the laboratory findings on the interference between Japanese Encephalitis and West Nile viruses are confirmed in field situations, the presently available effective JE vaccine may be helpful for controlling WN infections also,” she added.
Preventive measures
According to specialists, an infection from West Nile Virus could be prevented by defending oneself from mosquito bites. Meanwhile, taking steps like carrying clothes that acts as a barrier to publicity to bites, lowering breeding websites, overlaying water storage containers, eliminating puddles and drainage of locations the place water accumulates, eliminating unusable containers the place water swimming pools, and controlling rubbish in yards and gardens may also stop this vector-borne illness.
Source: www.financialexpress.com”