Fighting Killer Bugs
West Nile Virus provokes effort to minimize threat from mosquitos.
Thursday, February 3, 2005
The mosquito population of Monterey County and California will begin to rise in the following months. As the region heats up, sitting water will start to swim with mosquito larva, and by summer the insects will have infested daily life.
The same thing happens every spring, but this year is different. This season marks the West Nile Virus’ second year in California, and the formerly annoying mosquito is now a potentially deadly threat to animal and human life.
Responding to this recent threat, the Mosquito and Vector Control Association of California (MVCAC) put the West Nile Virus at the center of its 73rd Annual Conference, which met in Monterey on Monday and Tuesday.
Researchers in other states have charted the virus’ increased activity in its second year affecting a region. Last year the virus killed 27 people in California, and infected roughly 800 others, with symptoms as serious as paralysis and as simple as a cough. Those numbers will be on the rise in the coming months, and public awareness and action against the spread of mosquitoes will be vital.
“[MVCAC] is the front-line defenders in the battle against the West Nile Virus,” says Ted Toppin of the MVCAC. By uniting the different regions of California under the common concern of disease control, and then representing those regions in Sacramento, the MVCAC gives researchers and residents alike a political presence.
“Our big battle in recent years,” says Toppin, “given state budget cuts, is to protect resources and to exempt mosquito control efforts from cuts. Here we are in the middle of the worst mosquito born disease and California hasn’t allotted any more funding.”
“Only additional funding,” says Toppin, “will save lives.”
Dennis Boronda is a biologist with this region’s mosquito control district, the Northern Salinas Valley Mosquito Abatement District (NSVMAD).
“[Residents] need to look for water in their backyard,” he says, “empty out containers [with standing water] and if they find any mosquitoes, let us know immediately.”
Reporting the presence of one or two insects might seem trivial, but “they can affect entire neighborhoods,” says Boronda. “Imagine [a mosquito] going 100 yards or less from where it hatched, laying eggs there… they can spread through entire cities that way.”
Residents’ involvement in mosquito control will be vital in reducing the damage that the virus will do. “We have no way to monitor people’s backyards,” says Boronda.
The virus poses not only a threat to people, but also to animals who tend to be more prone to the disease. Especially at risk are local species of birds. “Hundreds of thousands of birds die from this,” says Boronda. Researchers are keeping a particularly close watch on the California condor, worried that the virus could finish their small endangered population.
The NSVMAD will be working all over the County to reduce the mosquito population. “There’s always been a concern about the possibility of a virus coming into the mosquito population,” says Boronda. Accordingly, measures have been worked out to contain and control the now very real disease.
The NSVMAD has taken three primary steps in the various hot spots around the County. “[Mosquitoes are] going to lay their eggs in water,” says Boronda, “so we get rid of stagnant water.” But such draconian methods can’t be applied to certain ponds, lakes or wetlands, which support wildlife habitats.
In cases where environmental concerns outweigh disease control concerns, “we use natural predators,” says Boronda. For this area, the NSVMAD commonly uses mosquito fish, which prey on the aquatic mosquito larva.
The introduction of mosquito predators often doesn’t effectively control the insect population. Mosquitoes, like most insects, survive by being so numerous. To deal with this, the NSVMAD have started spraying mosquito breeding grounds with chemicals.
Aware of the dangers of introducing chemicals into a habitat, the NSVMAD uses Bti, a biological agent that targets and kills mosquito larva only. “[Bti] allows the mosquitoes’ predator population to grow,” says Boronda, “so that they can control the mosquitoes.”
Earlier in the NSVMAD’s 50 year existence, the group would have eliminated wetland areas and sprayed wildlife habitats with harmful chemicals to control the virus. “[Current methods] take more time, and are a little more expensive,” says Boronda, “but they work better. We’re more into enhancing wetlands.”