The Kerala government on Tuesday (May 7) said that cases of West Nile fever have been reported from three districts in the state – Thrissur, Malappuram and Kozhikode. One person died of the viral disease on Monday and six other cases have been reported in recent days.
State Health Minister Veena George has now asked these regions to stay vigilant and ordered that steps be taken for mosquito control, according to a statement released by her office.
The minister said that there was no need to be concerned about the virus, but requested anyone showing signs of fever or other symptoms of the West Nile infection to seek treatment immediately, a PTI report said.
According to the health department, West Nile virus can cause a fatal neurological disease in humans. However, approximately 80 percent of those infected will not show any symptoms. Here’s what you need to know about the disease, how it spreads, its symptoms, treatment and prevention.
What is the West Nile Virus?
The West Nile Virus (WNV) is a mosquito-borne, single-stranded RNA virus. It is a flavivirus and is related to the viruses that cause Japanese encephalitis and yellow fever.
How does the West Nile Virus spread?
Culex species of mosquitoes act as the principal vectors for transmission. Infected mosquitoes spread the disease among humans and animals, including birds, which are the reservoir host of the virus.
“Mosquitoes become infected when they feed on infected birds, which circulate the virus in their blood for a few days. The virus eventually gets into the mosquito’s salivary glands. During later blood meals (when mosquitoes bite), the virus may be injected into humans and animals, where it can multiply and possibly cause illness,” says the World Health Organisation (WHO).
WNV can also spread through blood transfusion, from an infected mother to her child, or through exposure to the virus in laboratories. It is not known to spread by contact with infected humans or animals.
According to the US Centers for Disease Control and Prevention (CDC), it does not spread “through eating infected animals, including birds.” The CDC notes that the incubation period for WNV disease is typically 2 to 6 days, but can range from 2 to 14 days, and can be several weeks in immunocompromised people.
To date, no human-to-human transmission of WNV through casual contact has been documented, says the WHO.
What are the symptoms of West Nile fever?
The disease is asymptomatic in 80% of the infected people. The rest develop what is called the West Nile fever or severe West Nile disease. For them, the symptoms include fever, headache, fatigue, body aches, nausea, rash, and swollen glands.
It usually turns fatal in persons with comorbidities and immuno-compromised persons (such as transplant patients). But the death rate is relatively low compared to Japanese encephalitis, which shows similar symptoms.