Context : The Kerala health department is on alert after the death of a 47-year-old from Thrissur due to the West Nile Virus.
What is West Nile Virus(WNV) ?
- The West Nile Virus is a mosquito-borne, single-stranded RNA virus.
- RNA virus is the virus that has single-stranded as well double-stranded RNA as its genetic material.
- Noticeable sickness because of RNA virus is (severe acute respiratory syndrome) SARS, influenza, common cold, Hepatitis B and C.
- It is a flavivirus associated with the viruses that cause St. Louis encephalitis, Japanese encephalitis, and yellow fever.
- The Flaviviridae are a cluster of positive, single-stranded, enveloped RNA viruses. Members of this cluster belong to a single genus, Flavivirus.
- They are observed in arthropods, (mainely ticks and mosquitoes), and can sometimes infect people.
- Culex species of mosquitoes act as the main vectors for transmission.
- It is transmitted by infected mosquitoes among and between people and animals, together with birds, which might be the reservoir host of the virus.
- Mosquitoes emerge as infected once they feed on infected birds, which circulate the virus in their blood for some days.
- The virus subsequently gets into the mosquito’s salivary glands.
- When mosquitoes bite, the virus can be injected into human beings and animals, in which it could multiply and probably cause illness.
- It also can spread through blood transfusion, from an infected mom to her child, or through exposure to the virus in laboratories.
- It isn't always known to spread through contact with infected people or animals.
- The disease is asymptomatic in 80% of the infected people.
- The rest develop what's known as the West Nile fever or severe West Nile disease. For them, the signs and symptoms include:
- fever, headache, fatigue, body aches, nausea, rash, and swollen glands.
- It usually turns deadly in people with comorbidities and immuno-compromised people (like in transplant patients).
- Severe contamination can result in neuroinvasive disease such as West Nile encephalitis or meningitis or West Nile poliomyelitis or acute flaccid paralysis.
- Neuroinvasive diseases are capable of infecting the nervous system and particularly the central nervous system.
- WNV-associated Guillain-Barré syndrome and radiculopathy have also been reported.
- Guillain-Barre syndrome is an unprecedented ailment in which the immune system of one’s body attacks its own nerves.
- Radiculopathy is a mechanical compression of a nerve root usually on the exit foramen or lateral recess
Cases in India :
- In India, antibodies against WNV were first detected in humans in Mumbai in 1952 and virus activity has since been reported in southern, central, and western India.
- WNV has been remoted in India:
- from Culex vishnui mosquitoes in Andhra Pradesh and Tamil Nadu,
- from Culex quinquefasciatus mosquitoes in Maharashtra, and
- from people in Karnataka.
Precaution against WNV:
- Since WNV outbreaks in animals precede human cases, the status quo of an active animal health surveillance system is beneficial in offering early warning.
- The peak for WNV infections usually coincides with the duration when mosquito vectors are most active and the ambient temperature is adequately high for virus multiplication.
- Hence, health agencies and authorities globally advice for personal protective measures to reduce the risk of mosquito bites including
- the use of mosquito repellents, and
- for public health departments to ensure larval source reduction particularly at breeding and resting sites for the mosquito vectors. Treatment No WNV-specific prophylaxis, remedy or vaccine is available. So, most effective supportive treatments are given to neuroinvasive WNV patients.
- The best way to avoid WNV is to prevent mosquito bites as well as to keep the surrounding in a neat and mosquito free state
- There are no specific vaccines or treatments for human WNV disease in this case scenario , there is a need for collective precautionary measures to be taken by the institutions as well as the individuals to prevent the spread.