Question

1-What are West Nile Virus symptoms, blood work, fever, all major sign and symptoms

2-Tests for detection – serological and DNA based (also includes V, B, P, G+/G-)

3-Pathogenesis – virulence factors, toxins spores etc how it damages our bodies

Answer 1

West Nile encephalitis is an infection of the brain caused by a virus known as West Nile Virus.

It is first identified in Uganda in 1937.The virus is commonly found in Africa,West Asia,and the middle east.Encephalitis means inflammation of the brain.The most common causes of encephalitis are viral and bacterial infections,including viral infections transmitted by mosquitoes.

West Nile virus infection is also called West Nile Fever or West Nile encephalitis.The virus is a type of arbovirus.It is the member of the Flavivirus genus and the family Flaviviridae.

Strains of the west nile virus have been commonly found in humans,birds and other vertebrate animals in Africa,Eastern europe,West Asia and the Middle east.

People get West Nile Virus fron bites of a mosquito(primarily the Culex pipiens mosquito) that is infected with the West Nile virus.This mosquito is often referred to as the house mosquito or the west nile mosquito.

The Culex species that transmits West Nile virus is called the house mosquito because it prefers to lay egg in small containers of stagnant water,which are common around homes.Humans are not their preferred meal,and they become infected by feeding on birds.The infected birds may or may not become ill.The birds are preferred and amplifying hosts of the virus and are important for the virus life cycle and transmission cycle.

Among birds,crows are most vulnerable to infection by the West Nile virus.They are often killed by the virus.The infected mosquitoes then transmit the virus when bite and suck blood from nearby people and animals and in the process,infect the virus into their victim.

The West Nile virus is not contagious.It cannot be transmitted from person to person.A person cannot get the virus,from touching and kissing a person who has the disease or from the health care worker who has treated someone with the disease.

Humans are celled "dead end" host for the virus,meaning that can be infected but whose immune system ususlly prevents the virus from multiplying enough to be passed back to mosquitoes and then spread to other hosts.

The incubation period(the time from infection to the development of the symptoms) for the West Nile virus is five to 15 days.

Mild or symptom free infection are common with West Nile virus.Among all people who become infected,only two out of 10 develop any symptoms.Of those,most only have mild symptoms similar to those of the flu,such as headache,body aches,joint pain,swollen lymph nodes,vomiting,diarrhea or rash.The symptoms are not severe enough for most people to seek medical care,but tiredness and weakness can last for several weeks.Typically,only one in 150 infections lead to severe or neuroinvasive infections.Neuroinvasive dusease is caused by infection and inflammation of the surface covering of the brain or deeper infection of the brain itself.

West nile virus can have some long-term effects after severe illness.West Nile virus meaningitis or encephalitis may result in a prolonged recuperation and rehabilitation period,especially in the elderly.memory loss,depression,irritability and confusio are the most prevalent residual effects.

Patients may also experience difficulty in walking,muscle weakness,jointpain,fatigue,vomiting,diarrhea and insomnia.

Symptoms in children and babies are basically the same as symptoms in adults.Children may complain of headache,may have fever,and may become lethargic.

Since most cases of west nile virus infection are mild,the prognosis for recovery is generally good.In severe cases,death rates are highest in the elderly.

A risk factor for developing a more severe case is being 50 years age or older.

It is estimated that likelihood west nile virus transmission from blood products at 2.7 infections per 10000 units of transfused blood.Donated blood that tests positive for the virus is not administered to patients.It is impossible to completely eliminate all risks of infection from blood products,but the blood supply is currently very unlikely to cause an infection.

The diagnosis of West Nile virus infection is confirmed with a blood or cerebrospinal fluid test(CSF) test to detect WNV-specific IgM antibodies.A CSF test requires a lumbar puncture to obtain a specimen.IgM antibodies represent recent infection and are usually detectable during active or recent infection within three to eight days after infection,but a negative infection within eight days should still be repeated if WNV infection is truely suspected.WNV IgM antibodies can persist for three months or more,so the test may be positive from a prior infection,or a positive test may be due to cross-reactivity with antibodies to other flaviviruses.Therefore,a positive WNV IgM antibody must be confirmed by much more specialised testing by CDC.

WNV-specific IgM antibodies appear soon after the IgM antibodies,and remain present for life,so testing for these antibodies is not helpful for diagnosis of new infection.It can help sort out past infection from new infection when a person lives in an area where a person lives in an area where WNV is active or has been exposed.

There is no specific treatment for West Nile Virus infection at this time.Intesive supportive therapy is directed towards the complications of brain infection.Anti-inflammatory medications,intravenous fluids,and intensive medical monitoring may be required on severe cases.In milder cases,over the counter(OTC) pain relievers such as ibuprofen or aspirin may help reduce symptoms of pain and fever.There is no specific antibiotic or antiviral for viral infection.There is no vaccine to prevent the virus.

Local and atste helath departments may monitor the bird population for virus,this includes surveillance of birds that are sick or have died of disease.Community soukd watch and remove sources of stagnant water to control the disease.Public or private mosquito-control programs may be warrented for prevention of West Nile virus infection.Rigorous surveillance and mosquito control programs halp to greatly reduce the likelihood that the virus may infect people.