And symptoms of west nile virus

Men between ages 60 and 89 are 20 times more likely to develop West Nile meningoencephalitis than the general population, while people with compromised immune systems are at a fold increased risk.

While meningoencephalitis shares many of the same neurologic symptoms of meningitis and encephalitis, they tend to be more severe and longer lasting and may, in some cases, become permanent with this particular complication. The risk of death is also higher, hovering between 12 percent and 15 percent.

The mortality risk among the elderly may be as high as 35 percent. West Nile poliomyelitis, like other forms of polio, is characterized by the acute and often incapacitating loss of motor control. Unlike other neurologic complications of West Nile fever, poliomyelitis may not be accompanied by fever, headache, or other common symptoms of infection.

The condition is characterized by the sudden onset of flaccid paralysis on side of the body, usually without the loss of sensation. The paralysis is often preceded by pain and can strike quickly, usually within two to eight days of the first appearance of symptoms.

Less commonly, West Nile poliomyelitis can affect the respiratory system and require mechanical ventilation to help the person breath. It can also cause the loss of sphincter control, resulting in urinary or fecal incontinence.

While the paralysis may lead to permanent impairment, milder cases can often improve significantly as the affected nerve cells gradually recover and reestablish connections. People with fewer affected limbs tend to show better improvement overall. With that being said, most of the strength recovery will occur during the first six to eight months following the onset of symptoms, eventually plateauing with less noticeable improvement.

West Nile reversible paralysis is a less severe, temporary form of paralysis, again affecting only one side of the body. Although the condition is not well understood, it is believed to be caused by inflammation of the same part of the spinal cord called the anterior horn that triggers poliomyelitis and Lou Gehrig's disease.

What differentiates West Nile reversible paralysis from West Nile poliomyelitis is that the reflex responses remain intact even when muscle weakness occurs. While the initial paralysis can be profound, it will eventually reverse with little visible impairment of motor function.

Getting a mosquito bite does not mean you will get West Nile fever. Most people infected with the West Nile virus will either never even know it or simply mistake it for a mild flu. Even if you discover you've been infected, the chances are good that you will get better without any problems or treatment. Get our printable guide for your next doctor's appointment to help you ask the right questions. With that being said, if you are elderly or immune-compromised, you need to seek immediate care if you experience a severe headache, high fever, neck stiffness, confusion, light sensitivity, or sudden muscle weakness.

These may be signs encephalitis or meningitis, both of which require emergency treatment. The West Nile virus is no longer a disease associated with foreign travel. Fatalities, which have mainly occurred among the elderly, have generally been low, the annual rate ranging from as few as 2 to as many as in the United States.

The symptoms of West Nile fever, if any, develop three to 14 days after being bitten by an infected mosquito. With mild infections, the febrile fever-related symptoms may resolve within days, but the fatigue and weakness can persist for weeks and even months in some people. One in infections will result in West Nile neuroinvasive disease WNND , in which the virus invades the central nervous system. Symptoms may include severe headache, neck stiffness, muscle weakness, tremors, disorientation, convulsions, paralysis typically reversible , and coma.

The majority of deaths are in people 70 and over. Causes of death include encephalitis-induced deep vein thrombosis DVT and aspiration pneumonia triggered by severe dysphagia the impairment or loss of the swallowing reflex. There is no specific treatment for West Nile fever.

Even so, the vast majority of people will recover without treatment or long-term consequences. Severe cases may require hospitalization to treat complications of the disease and prevent secondary infections. Sign up for our Health Tip of the Day newsletter, and receive daily tips that will help you live your healthiest life.

West Nile virus. In: StatPearls [Internet]. Updated November 20, Sejvar JJ. Clinical manifestations and outcomes of West Nile virus infection.

Published Feb 6. West Nile virus in the United States: an update on an emerging infectious disease. Am Fam Physician. West Nile virus neuroinvasive disease. About 1 in people who are infected develop a severe illness affecting the central nervous system such as encephalitis inflammation of the brain or meningitis inflammation of the membranes that surround the brain and spinal cord.

Skip directly to site content Skip directly to page options Skip directly to A-Z link. West Nile virus. Section Navigation. Facebook Twitter LinkedIn Syndicate. Minus Related Pages. Symptoms No symptoms in most people. Symptoms of severe illness include high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness and paralysis. Severe illness can occur in people of any age; however, people over 60 years of age are at greater risk for severe illness if they are infected 1 in 50 people.

People with certain medical conditions, such as cancer, diabetes, hypertension, kidney disease, and people who have received organ transplants, are also at greater risk. This content does not have an English version. This content does not have an Arabic version. Overview A mosquito-transmitted virus causes most cases of West Nile infection. Request an Appointment at Mayo Clinic. West Nile virus transmission cycle Open pop-up dialog box Close.

West Nile virus transmission cycle When a mosquito bites an infected bird, the virus enters the mosquito's bloodstream and eventually moves into its salivary glands. Share on: Facebook Twitter. Show references West Nile virus.

Centers for Disease Control and Prevention. Accessed Nov. Petersen LR. Epidemiology and pathogenesis of West Nile virus infection. Clinical manifestations and diagnosis of West Nile virus infection. West Nile virus infection. Mayo Clinic; Treatment and prevention of West Nile virus infection. Tosh PK expert opinion.