West Nile Virus: A Historical Account

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For most of my life, talk of West Nile Virus has been common. However, it wasn’t until 1999 that it first appeared in the North America.1 This disease has a long history, which is mostly unknown by many American’s due to its rather recent occurrence.

West Nile Virus is a mosquito-borne zoonotic virus, which can cause an inflammation of the brain known as encephalitis.2 West Nile Virus gets its name from the region where it was first isolated. This region, unsurprisingly, was the West Nile district of Northern Uganda.1 The virus was first discovered in this region in 1937 in a patient who was participating in a study of the yellow fever virus.1 When mice were inoculated with serum from this patient, the virus was isolated and found to exhibit similar properties to those observed with St. Louis encephalitis virus and Japanese B encephalitis virus. This ground-breaking study showed that the virus primarily infected the central nervous system, suggesting the it was neurotropic in nature.1

The main characterizations of West Nile Virus were completed during outbreaks in the Mediterranean basin in the 1950s and 1960s. 1 The first recorded epidemic took place in Israel in 1951. The majority of the infected were small children and the primary recorded symptoms included fever, headache, abdominal pain, and vomiting.1 The epidemiology and ecology of the disease was further understood during additional outbreaks in Egypt between 1951 and 1954.1 In 1951, an extensive study of the disease began in upper Nile Delta region. During these studies researchers identified virus vectors and experimentally infected birds, equines, arthropods, and humans.1 It was concluded that mosquitoes were the primary vectors due to their ability to maintain the vector cycle and the observation that the virus could only be isolated from mosquitoes and not from other arthropods.1 Subsequent outbreaks took place in Israel, France, South Africa, Russia, Spain, and India.1

According to several accounts, 1996 marked a turning point for the disease. During this year, an outbreak occurred in Bucharest, Romania and it was the first to take place predominantly in an urban area and the first to result in a larger part of CNS infections. Studies have suggested that the deterioration of Bucharest lead to environments conducive to a high population of mosquitoes and decreased protection against them (i.e. windows, screens, and doors).

In 1999, West Nile Virus hit North American for the first time on record. The outbreak occurred in the Queens area of New York City. This outbreak occurred in residents of the same 16 square mile area. The common factor amongst all of those infected was their recent, previous engagement in outdoor activities, suggesting that the virus was once again transmitted through mosquito vectors.1 There were 62 cases of West Nile Virus reported by the end of summer 1999, 59 of which resulted in hospitalization.1

The panic of American’s escalated in 2002 when an unprecedented outbreak took place in the US. When reported in January of 2003, the 2002 outbreak in the US resulted in 4156 cases, including 284 deaths. Louisiana, Mississippi, and Chicago saw exceptionally high numbers of cases during this outbreak.1 As of 2003, human cases have been reported in all states in the continental US except for Maine, Oregon and Washington.2

Spread of West Nile Virus up to and Including 2003 https://www.pinterest.com/pin/549298485774436132/
Spread of West Nile Virus up to and Including 2003 https://www.pinterest.com/pin/549298485774436132/

Although there is currently no vaccine available for treating the virus, most cases of West Nile Virus are not fatal. According to Pennsylvania’s West Nile Virus Control Program, “in order to protect yourself against the virus, you should Wear shoes, socks, long pants and a long-sleeved shirt when outdoors for long periods of time, or when mosquitoes are most active.  Consider the use of mosquito repellent, according to directions, when it is necessary to be outdoors. Wash all treated skin and clothing when returning indoors.”2

References:

  1. Sejvar, James J. “West Nile Virus: An Historical Overview.” The Ochsner Journal.

Ochsner Clinic, L.L.C. and Alton Ochsner Medical Foundation, n.d. Web. 24

June 2015.

  1. “West Nile Virus Website.” West Nile Virus Website. Pennsylvania’s West Nile

Virus Control Program, n.d. Web. 24 June 2015.

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