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
Bone Cells Bone cells may be divided into two broad classifications depending on whether they make bone or resorb it. Osteoblasts make bone, while Osteoclasts resorb or take aw

Question 1: What are the requirements you need to satisfy for internet usage and remote data capture under 21 CFR parts 11 in a clinical trial? Define 21 CFR parts Me

Define Food quality factors and their measurement? Appearance; textural, flavour, nutritional, sanitary and keeping factors; quality standards, objective and organoleptic evalu

Changes those are associated with programmed cell death, containing release of apoptotic bodies, blebbing, and nuclear fragmentation.

Q. What are the endocrine glands that regulate sexual activity in males? How does this regulation work and what are the involved hormones? In males the sexual activity is regul

Explain about the Brownian ratchets and molecular motors ? How work is carried out by molecules within biological cells is essential to understanding how cells function. A clue

What is Class Reptilia ? Class Reptilia include the vertebrates that have successfully transitioned to a terrestrial lifestyle by evolving protective scales and a "land egg."

Q. Effect on Microbial Growth of pH? Every microorganism has a minimal, a maximal, and an optimal pH for growth. In general, bacteria grow in the pH range of 6.0-8.0, yeasts 4

Define Assessment of Calcium Status and Calcium Requirements? There is no biochemical indicator, which can clearly reflect calcium status. It has also been seen that in case of

Raw Material for Industry - impacts on biodiversity The industry, producing goods and services, relies and impacts on biodiversity directly. Much of the raw material that goes