Tag Archives: mosquitoes

International, Technology

Bacteria can stop Dengue Fever

“This is a simple, non-chemical, non-harmful way to reduce the threat of dengue to humans. It could have a transformative effect on the health of literally millions of people worldwide.”–Alun Lloyd

North Carolina State University researchers have discovered that common bacterias can stop the spread of Dengue fever.  The research involved scientists from Australia.

The researchers found that a bacterium called Wolbachia, which is not harmful to humans, can block the transmission of Dengue in mosquitoes.  They think by releasing mosquitoes infected with Wolbachia, it could radically reduce cases of Dengue fever.


Opinion, U.S.

Dumb Americans: New study shows that many U.S. citizens, living in big cities, don’t know that mosquitoes spread disease

“High general knowledge of mosquitoes and concern about mosquito biting was not sufficient to encourage residents to dump standing water, and even in yards where residents did empty containers, there were still many mosquito breeding sites.”-Zara Dowling, researcher

The University of Maryland discovered that many city dwellers are unaware that standing water is a breeding ground for mosquitoes.  Not only that, those people who know are too lazy to dump the water.

The study also looked at the class level of the city dwellers and found, surprisingly, that while upper income families were more educated about the dangers of mosquitoes, they were less likely to take action (wealth breeds laziness?), compared to middle and lower income families!

54% of the families surveyed had a high number of mosquitoes on their property.

However, the University of Maryland must be criticized for trying to imply that most U.S. citizens are dumb, or lazy, when it comes to mosquito control.  The study looked at only 242 urban households!  That’s not enough to make such an extrapolation.

Idaho, International, U.S.

Dengue & West Nile influenced by temperature changes, flooding

“Traditional explanations for the seasonal increase in dengue are not consistent with my experience in Thailand, Peru, and Puerto Rico.”-Doctor Thomas Scott

A recent study shows that long hot seasonal temperatures help the spread of Dengue.  The areas of the world, where Dengue is becoming more prevalent, are areas that are not cooling off as they used to, and are subject to radical swings in warmer temps.

The study, “Impact of Daily Temperature Fluctuations on Dengue Virus Transmission by Aedes aegypti”, shows that without the usual cold seasons the mosquitoes, that spread the disease, stay alive much longer increasing their chances of catching Dengue from humans, and spreading it.

The study also showed that mosquitoes are less likely to spread disease during cooler temperatures, and more likely during hot weather: “…whereas transmission probability is estimated to be 0.11 at a constant mean temperature of 14 °C, it shows a 2.7-fold increase with a DTR [diurnal temperature range] of 20 °C.”

While many parts of the World are experiencing warmer than normal weather, here in Idaho our weather is much cooler than normal.  That is keeping cases of West Nile virus way down, so far.

The big concern in Idaho is protecting horses.  Horses are more susceptible to dieing from West Nile, than humans.

Local mosquito eradication officials are reporting that, so far, there’s a drop in West Nile infected mosquitoes, possibly due to the cooler weather.  However, they pointed out that mosquitoes with West Nile usually show up in the later half of Idaho summers.

Another factor in favor of mosquitoes is flooding.  Parts of Idaho have been hit with increased seasonal flooding, and the cooler weather (resulting in less evaporation) means there are large areas of standing water, perfect for mosquitoes.

Officials are already taking action by spraying insecticides on ponds, and asking property owners to drain standing water.

The Center for Disease Control and Prevention reports that Idaho, Oregon and Washington state are free of any West Nile cases (as of 26 July 2011).  It could be due to the cooler than normal weather.

The CDC reports human cases of West Nile in the following U.S. states: Arizona, California, Georgia, Mississippi, South Dakota, Texas, Virginia, and Wyoming.

According to the most recent CDC Dengue HealthMap, there are no cases of domestically acquired Dengue fever within the United States.