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Bite me: When the latest buzz isn’t a good thing

Beware of the Asian tiger Mosquito: CDC photo

The recent rains hitting the southwest has brought concerns about Mosquitoes but it is not their bite per se that are the problem, it is the hidden virus that those bites brings.

For Texas, the main virus of concern is West Nile Virus (WNV) where Harris county – which houses city of Houston – has already reported first case of WMV in May 2015.  Normally WNV occurs later in the summer. The sprayers are out but with that amount of standing water, it is impossible to eradicate.

In most people WNV has flu like symptoms but for more elderly people or immune compromised, it can lead to meningitis or encephalitis. In non-medical terms that is brain swelling.

As for preventing WNV, there is no vaccine against it and it’s treatment will only be management of the symptoms. The best you can do is to protect yourself against bites especially when the mosquitoes are active around dawn and dusk.

A Rash from Chikungunya : Wikepedia/ cc licence

There is another disease called “Chikungunya” that is spreading up from Central America via mosquitos. Symptoms of Chikungunya are typcially a fever and severe joints pains. Unlike the mosquitos that carry WNV, the ones that carry chikungunya, bite during the day.

One particularly aggressive Mosquito that carries Chikungunya is the Asian tiger mosquito which is distinct in it’s black and white looks. It can also hear it buzzing. It is not a native to US but an immigrant species. It bites everything – cats, dogs and humans.

Thinking of getting away from this by going North or East. Not so fast. There is St. Louis encephalitis virus (SLEV) to consider that occurs in more temperate zones late in the summer.

Most cases of SLEV disease have occurred in eastern and central states. Most persons infected with SLEV have no apparent illness. Initial symptoms of those who become ill include fever, headache, nausea, vomiting, and tiredness. Severe neuroinvasive disease (often involving encephalitis, an inflammation of the brain) occurs more commonly in older adults. In rare cases, long-term disability or death can result.

What about quitting the US and going somewhere far away like Australia? Not so fast. They have their own version of WNV called “Kunjuin virus” in Queensland.

So accepting mosquitos are out there waiting to bite, what can you do about them: Consumer reports did some tests. Best products are the ones with Deet as an ingredient.

For the first time ever in Consumer Reports’ tests of insect repellents, new, safer products—made with milder, plantlike chemicals—were the most effective. (Check our insect repellent Ratings and buying guide.) The top scorers outperformed products that contained deet, a chemical that did best in our previous Ratings but can cause serious side effects.

The active ingredients in the top repellents are chemically synthesized compounds that are similar to or come from natural ingredients. The secret sauce in the best-scoring Sawyer product is picaridin; in the Repel it’s oil of lemon eucalyptus. They are not side-effect-free, but “those problems are much less severe than deet,” says Urvashi Rangan, Ph.D., executive director of Consumer Reports’ Food Safety and Sustainability Center. “Still, all repellents should be used sparingly and only for the time you need them—especially on children and older people.”

That’s why an effective bug-avoidance strategy requires a full arsenal. Our new tests identify non-chemical approaches that offer some relief (setting up a fan on your back patio, for example) and those that don’t help much if at all (think citronella candles, wristbands, and “all-natural” products with geraniol, lemongrass, and rosemary oils).

Take care out there.
Galen.


 

Primer on West Nile Virus

Source: US Geological Survey

Since West Nile virus (WNV) was first isolated in 1937, it has been known to cause asymptomatic infection and fevers in humans in Africa, West Asia, and the Middle East. Human and animal infections were not documented in the Western Hemisphere until the 1999 outbreak in the New York City metropolitan area. Since then, the disease has spread across the United States. In 2003, WNV activity occurred in 46 states and caused illness in over 9,800 people.

WNV is transmitted to humans through mosquito bites. Mosquitoes become infected when they feed on infected birds that have high levels of WNV in their blood. Infected mosquitoes can then transmit WNV when they feed on humans or other animals.

WNV is not contageous from person to person and there is no evidence that a person can get infected by handling live or dead infected birds. But, to add a further level of safety, if birds or other potentially infected animals must be handled, a protective barrier (e.g., gloves, inverted plastic bags) should be used.

Most WNV infected humans have no symptoms. A small proportion develops mild symptoms that include fever, headache, body aches, skin rash and swollen lymph glands. Less than 1% of infected people develop more severe illness that includes meningitis (inflammation of one of the membranes covering the brain and spinal cord) or encephalitis. The symptoms of these illnesses can include headache, high fever, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, and paralysis. Of the few people that develop encephalitis, a small proportion die but, overall, this is estimated to occur in less than 1 out of 1000 infections.

There is no specific treatment for WNV infection or vaccine to prevent it. Treatment of severe illnesses includes hospitalization, use of intravenous fluids and nutrition, respiratory support, prevention of secondary infections, and good nursing care. Medical care should be sought as soon as possible for persons who have symptoms suggesting severe illness.

Individuals can reduce their contacts with mosquitoes by taking these actions:
When outdoors, wear clothing that covers the skin such as long sleeve shirts and pants, apply effective insect repellent to clothing and exposed skin, and curb outside activity during the hours that mosquitoes are feeding which often includes dawn and dusk. In addition, screens should be applied to doors and windows and regularly maintained to keep mosquitoes from entering the home.

Primer on Chikungunya

Source : CDC website : Chiknungunya

Symptoms

  • Most people infected with chikungunya virus will develop some symptoms.
  • Symptoms usually begin 3–7 days after being bitten by an infected mosquito.
  • The most common symptoms are fever and joint pain.
  • Other symptoms may include headache, muscle pain, joint swelling, or rash.
  • Chikungunya disease does not often result in death, but the symptoms can be severe and disabling.
  • Most patients feel better within a week. In some people, the joint pain may persist for months.
  • People at risk for more severe disease include newborns infected around the time of birth, older adults (≥65 years), and people with medical conditions such as high blood pressure, diabetes, or heart disease.
  • Once a person has been infected, he or she is likely to be protected from future infections.

Diagnosis

  • The symptoms of chikungunya are similar to those of dengue, another disease spread by mosquitoes.
  • See your doctor if you develop the symptoms described above.
  • If you have recently traveled, tell your doctor.
  • Your doctor may order blood tests to look for chikungunya or other similar diseases.

Treatment

  • There is no medicine to treat chikungunya virus infection or disease.
  • Decrease the symptoms:
    • Get plenty of rest
    • Drink fluids to prevent dehydration
    • Take medicines, such as ibuprofen, naproxen, acetaminophen, or paracetamol, to relieve fever and pain.