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New Mosquito-Borne Diseases in U.S.

Dengue fever is one of two mosquito-borne illnesses that have Florida health officials increasingly worried about a major outbreak. The other one is West Nile virus, which first showed up in the United States in 1999 and quickly moved south. Last year, 53 of Florida?s 67 counties were under medical alert for the virus.

Now officials worry that dengue fever will also spread to Florida. In recent years, there have only been about four cases a year, all imported by people who had were bitten in other countries.

The disease is found throughout the Caribbean and Central and South America. ?We?re certainly on the border of a real hotbed of dengue,? says Dr. Richard Duma, director of infectious diseases for Halifax Medical Center and an international expert in the field. ?It?s important for people to realize that the ingredients for a sizable outbreak of dengue are here.?

Florida?s transient population of residents and visitors worries health officials, particularly because so many tourists come from Brazil, which has had at least 104,469 cases of dengue and 40 dengue deaths since January. Cuba also has recently experienced an outbreak, although Castro says the disease is now eradicated there, and 111 cases of dengue have been reported in Hawaii since last June. The World Health Organization estimates there may be 50 million cases of dengue infection each year, including hundreds of thousands of cases of the more severe dengue hemorrhagic fever, which kills about 5 percent of those infected.

Dengue comes on suddenly, usually starting with a headache and high fever. In most patients who are infected for the first time, the symptoms of high fever and severe joint and muscle pain disappear in about a week.

Both dengue and West Nile are carried by the same two species of mosquitoes, which are common in Florida and breed in small puddles of water. Jonas Stewart, director of the East Volusia Mosquito Control District says, ?If you have an old bucket right outside the door and it?s boiling with mosquitoes, even if we spray up and down the street, we?d only get a few.?

The last dengue epidemic in Florida took place in 1934, Duma says. It was severe, striking more than 10 percent of the state?s population. Health officials are asking doctors to make every effort to diagnose mosquito-related illnesses by taking blood samples and sending them to state laboratories and alerting state health officials to a possible case. Duma says, ?Since this is right at our doorstep, we really have to pay attention. We can?t ignore it.?

To learn more,click here.

President Fidel Castro has declared victory in Cuba?s military-style campaign against dengue fever. ?The dengue virus has been eradicated in our homeland,? Castro says.

Cuba had earlier reported two deaths among the dengue cases in Havana in recent months, although Castro says this is the final fatal toll. On Jan. 12 Cuba launched a highly organized and widespread education and fumigation campaign aimed at wiping out the mosquito that causes the virus. During Cuba?s campaign, homes and other buildings, especially in Havana, were repeatedly sprayed over more than three months, sometimes several times a week.

Cuba suffered a serious dengue epidemic in 1971 that made more than 400,000 people sick. During another dengue epidemic 10 years later, Cuba reported 350,000 cases.Earlier this month, Brazil launched a similar battle in Rio de Janeiro against the mosquitoes that carry the virus. As of early March, more than 72,000 cases resulting in 28 deaths had been reported in that region. Peru, Venezuela and El Salvador have also recently reported outbreaks.

To learn more,click here.

A needle that mimics the mosquito?s unique stinger, which makes injections painless, has been developed by a team of Japanese microengineers.

A mosquito can stab you with its proboscis without you feeling a thing. It then injects anticoagulant saliva to stop your blood clotting while it feeds, and this is what carries the bacteria that cause irritation and pain.

Seiji Aoyagi and his colleagues at Kansai University in Osaka concluded that the initial bite is painless because the mosquito?s proboscis is highly serrated. Unlike the smooth surface of a syringe needle, which puts a lot of metal in contact with skin tissue, the jagged edge of the proboscis leaves only small points in contact. This greatly reduces stimulation of the nerves, says Aoyagi, causing far less pain.

To mimic this effect, Aoyagi and his team created a needle just one millimeter long and 0.1 millimeters in diameter. They did this by etching slices of silicon dioxide into a jagged shape and then bonding them together. The needle?s walls are just 1.6 micrometers thick.

Then they fitted the needle with a five-millimeter-wide tank, which can store blood or fluids collected by the needle. An optical fiber inserted in the tank allows doctors to analyze samples.

To test the needle?s strength, the researchers pushed the needle into a piece of silicone rubber, which has puncture resistance similar to skin, that was wrapped around a vessel containing a red dye. The tank filled with dye, indicating that the needle was able to puncture the skin.

The inventors hope the microneedle will be the forerunner of small wireless devices for collecting blood that could be permanently attached to the body. Such devices could monitor blood-sugar levels in diabetic people or collect blood samples from patients for diagnosis in a lab.

So those of us who hate blood tests and injections (doesn?t everyone?) now have something to thank mosquitoes for.

Want to shape-shift into a fly (or mosquito) on the wall? Read ?Shaman, MD? by Dr. Eve Bruce,click here.

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