Tiny Shrimp May Reduce Need for Mosquito Pesticides
an article by Tony Dominski
In response to the rapid spread of West Nile virus in the United States, there has been has been widespread application of mosquito-killing pesticides. These are toxic to human beings and natural ecosystems.
Fortunately, alternative non-toxic mosquito control agents are now under development. These include fish, bats, bacteria, and tiny shrimp known as copepods.
University of Florida researchers have shown that copepods can reduce West Nile mosquito populations by eating mosquito larvae in old tires and other water-holding containers [see Internet article]. Copepods were also used successfully in Vietnam to control the mosquitoes which carry dengue fever.
The Vietnamese dengue mosquitoes were breeding in water storage containers near people’s homes. Pesticide control has not been very effective due to late reporting of epidemics and rapid return of mosquitoes after spraying. Therefore, public health workers in Thuongtin district, Hatay province, worked with school children and community organizations to seed drinking water containers with mosquito-eating copepods and clean up discarded water containers.
As described in an internet article, this two-fold program in Vietnam succeeded in eliminating dengue fever in 32 of 37 communes and drastically reducing it in the other five. Surrounding communes which had not been treated continued to have high dengue fever infection rates. In 2004 Viet Nam reported 73,300 cases of dengue fever infections, including 101 fatalities.
The annual cost of the Vietnamese copepod and container cleanup program was $2 per person, including administrative costs. But the post-program expansion was estimated to cost less than $0.20 per person. Another similar successful program in Rangoon and Burma involved seeding voracious dragonfly larvae into domestic water storage containers.
These inspiring examples raise the possibility that eco-friendly bio-control of mosquitoes could be implemented worldwide and at an affordable price.
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