PANAMA CITY -- They’ve been called “suicide mosquitoes,” dead-end bugs and even Frankenskeeters.
They’re gene-altered mosquitoes, and Panama is among a growing list of countries that are testing to see whether they have a place in the public health arsenal in the war against mosquito-borne diseases such as dengue fever.
Dengue, which isn’t well-known outside tropical regions, is on the rise worldwide, with outbreaks reported this year in Texas and Florida. The mosquito that carries the dengue virus has spread to 100 countries and potentially exposes 2.5 billion people to the excruciating disease, also known as bonebreak fever. Some 50 million to 100 million people contract dengue each year, of which about 25,000 die, the World Health Organization reports.
“A person with dengue will be prostrate for several days,” said Dr. Carlos Galvez, the head epidemiologist for Panama’s Health Ministry. “They grow dehydrated very fast. In a matter of hours, the cases can grow more complicated.”
This has been a particularly bad year for dengue in the Western Hemisphere, with the Pan American Health Organization reporting 1.4 million cases. The Florida Department of Health issued an alert in late August amid an outbreak there, and the state had reported 19 cases by mid-September, none lethal.
Panama has one of the most developed public-health systems in Latin America, a legacy of the U.S. military presence during much of the 20th century to oversee the operation of the Panama Canal. Yet even Panama struggles to cope with a type of mosquito known as Aedes aegypti, an aggressive urban dweller originally from North Africa that’s the principal carrier of the dengue virus.
Teams patrol the streets fumigating with insecticide in a constant battle against the mosquito, and public service ads remind Panamanians to drain standing water in eaves, buckets, flowerpots and old tires, where mosquitoes breed.
Before long, public health officials may have a new tool – OX513A – a genetically modified mosquito from a British biotech company, Oxitec Ltd. of Abingdon, England, that’s a spinoff from Oxford University.
Oxitec mosquitoes have been altered to contain a “lethality gene.” When the mosquitoes, all male, are released into the wild, they mate with females but the offspring don’t survive. That’s why they’re called “dead end” bugs. Only if they’re exposed to tetracycline, an antibiotic, do the transgenic mosquitoes survive.
If Panama’s National Biosafety Commission gives the green light, some time early next year technicians will release tens of thousands of gene-altered mosquitoes in Arraijan, a bedroom community that’s across the canal from Panama City at the canal’s Pacific end.
“We plan to do about 50,000 per week,” said Dr. Nestor Sosa, the head of the Gorgas Memorial Institute for Health Studies, an autonomous public research body. “You have to have a proportion of at least 10 to 1 (transgenic) mosquitoes to native mosquitoes. You have to overwhelm them.”
If all goes according to plan, the OX513A release will result in a drop in the mosquito population.
“If you lower the number of mosquitoes, you lower the possibility of infection with dengue,” Galvez said.