West Nile virus: All about this mosquito-borne disease
Recently, Kerala was put on alert after a case of West Nile virus led to the death of a 47-year-old in its Thrissur district. As you already know, the South Indian state have also reported cases of other life-threatening viruses such as the Tomato flu, Zika virus and Nipah virus in the recent past. For those of you who didn’t know, this is not the first time West Nile virus has been detected in Kerala. As a matter of fact, the mosquito-borne virus was first reported in the year 2006, followed by 2011 and 2019 and had even claimed a few lives back then. In this context, let us explore more about the West Nile virus.
Origin of the West Nile Virus
All of know that the West Nile virus originated in humans. But do you know where the virus was first detected? Well, it was first found in a female resident of the West Nile district of the African country Uganda in 1937. Within a few years, in 1953, it was also identified in birds (such as crows, doves and pigeons) along the delta region of the river Nile. Since the virus originated in the West Nile district along the river Nile, it was named as the West Nile virus.
Known as WNV in short, this virus was not regarded as pathogenic until 1997 when an outbreak was detected in Israel among several migratory bird species, killing many in the process. From there, it spread to Tunisia, followed by USA, Canada and Venezuela.
By 1999, the virus had spread across all major continents namely Africa, Europe, the Middle East, North America and West Asia and was detected among both birds and humans.
How is the virus transmitted?
For those of you who’re hearing of the West Nile virus for the first time, here’s a heads-up: It is a mosquito-borne disease much like dengue and yellow fever. It is caused by the Culex species of mosquitoes who are the carrier of this single-stranded RNA (viruses that do not replicate using DNA) virus. Mosquitoes catch this infection from infected birds and transmit it to humans. The mosquitoes first feed on infected birds and then carry the virus in their salivary glands which then gets circulated once they go and feed on the blood of human beings.
Apart from mosquito bites that can directly infect a person, WNV can also spread when a person undergoes blood transfusion from an infected individual. However, till date, no human-to-human transmission of this virus has been detected.
Symptoms of West Nile virus
Although the West Nile virus has claimed the life of a middle-aged individual in Kerala recently, 80 per cent of the infected people remain asymptomatic. The symptoms of West Nile fever include headache, fatigue, body ache, nausea, rashes and at times swollen glands. In rare cases, it can lead to paralysis, meningitis (tissue inflammation surrounding brain and spinal cord region), encephalitis (brain inflammation) and even death, especially in people with co-morbidities and weak immunity.