West nile virus infection, Biology

West Nile virus infection

West Nile virus (WNV) is a type strain of flaviviruses and is related to Japanese encephalitis group. The virus was first isolated from a woman in the West Nile District of Uganda in 1937. The most serious manifestation of WNV infection is fatal encephalitis in humans and horses, as well as mortality in certain domestic and wild birds. The ecology was characterized in Egypt in the 1950s. The virus became recognized as a cause of severe inflammation of the spinal cord and brain in humans during an outbreak in Israel in 1957. Equine disease was first recorded in Egypt and France in the early 1960s. Recent outbreaks of WNV encephalitis in humans have occurred in Algeria (1994), Romania (1996-1997), Czech Republic (1997), Congo (1998), Russia (1999), USA (1999-2001) and Israel (2000). Epizootics of disease in horses occurred in Morocco (1996), Italy (1998), USA (1999-2001) and France (2000). WNV is highly prevalent in India, it is known to be active in mosquitoes, birds and pigs and usually causes a mild, non-fatal dengue like illness in humans. However, febrile illness in epidemic form and clinically overt encephalitis cases were observed in Udaipur area of Rajasthan, as well as Marathwada and Khandesh areas of Maharashtra.

Transmission to humans is through mosquito bite. A mosquito becomes infected by biting a bird that carries the virus. The Culex mosquito and many other insects found positive include species that feed on both avian and mammalian hosts. Recent studies in the lab indicate that WNV can be transmitted from bird-to-bird. This transmission from bird-to-bird, without the intervention of mosquitoes raises new questions about methods of transmission of the disease. In south India, JEV/WNV neutralizing antibodies were detected in birds mainly from the pond herons (Ardeola grayii) and cattle egrets (Bubulcus ibis). This indicates the possible involvement of ardeid birds in the natural cycle of WNV in India.

Symptoms and lesions: WNV is primarily an avian disease and as many as 10,000 crows died from the spreading infections in metropolitan New York in 2000. The deaths of numerous horses in the area also were attributed to the virus, which caused encephalitis. It is generally a milder infection with a fatality rate of 3% to 15% of all human cases and symptoms of fever, headache, body aches, skin rashes and swollen lymph glands. More severe infections may be a neck stiffness, disorientation, coma, tremors, convulsions, muscle weakness and paralysis.

Diagnosis: WNV infection is diagnosed by serological methods. In a human serum samples, MAC ELISA (IgM-antibody capture ELISA) is routinely used to detect acute infection. A commercially available arboviral immunofluorescence assay has been used for the screening of WNV infection in human. Recently, the RT-PCR and Real Time PCR methods for the detection of virus specific genome have been extensively used by several workers.

Prevention and control: In India, since no studies have been carried out for the control of WNV, the strategies recommended for the control of Culex mosquitoes, the known vectors of JEV could be applicable. The integrated vector control strategies includes the use of personal protection measures like protective clothing, bed nets, both chemical and neem-based repellants, insecticides, insecticide impregnated curtains, and biological control methods by larvivorous fish, introducing natural parasites, predators and bacterial agents.

Posted Date: 9/18/2012 8:57:17 AM | Location : United States







Related Discussions:- West nile virus infection, Assignment Help, Ask Question on West nile virus infection, Get Answer, Expert's Help, West nile virus infection Discussions

Write discussion on West nile virus infection
Your posts are moderated
Related Questions
SYNAPSE - The point where 2 neurons combine is synapse. It is of 2 types - (i) Axosomic (between axon & cyton) (ii) Axodendric (between axon & dendron) Axon is term

FAT SOLUBLE VITAMINS Vitamin A Vitamin A may be of most practical importance in cattle feed. Vitamin A is essential for normal growth, reproduction, maintenance of epithel

Disaccharides can be understood as follows 1.Sugars made up of the two monosaccharides held together by the covalent bond; like sucrose and lactose . 2. Type of sugar (sacch

Which are plant tissues that form the plant roots? Roots have a central portion called medulla made of vascular tissue outer phloem and inner xylem. Medulla is delimited by per

What is the photoperiod? The Photoperiod is the daily time period of light exposure of a living being and the photoperiod may differ according to the period of the year.

What is Prokaryotic Gene Expression ? Control of prokaryotic gene expression occurs primarily at the level of transcription. Prokaryotic genes are arranged in units consisting

Define Factors affecting Absorption of Dietary Iron? There are mainly four factors that determine iron bioavailability absorption from the diet. These include: i) Form of ir

Industrial Effluents - Causes of Water Pollution Most industrial operations produce effluents that are discharged into nearby river or any other water body. The industrial eff

Define the term Ancestral characteristic A character shared by all members of a taxonomic group of organisms (taxon) and used to define the unique nature of the group. The cha

Characteristics of Thick Gingiva  Relatively flat soft tissue and bony architecture  Dense fibrotic soft tissue  Relatively large amount of attached gingiva  Thick und