West Nile Virus - Research Paper Example

Environmental Studies: West Nile Virus TABLE OF CONTENTS I. Introduction II. Project Objectives III. Methodology IV. Principles for Safe and \Effective Control Measures for Mosquitoes at State and Local Level V. Summary and Conclusions I. Introduction West Nile Virus was first discovered in the African continent, in Uganda in 1937. It has spread outside its native borders to Europe and United States. The virus causes illness to birds, horses as well as humans. It was first discovered in New York City in 1999. Since then, it has spread to 47 states. It has been detected in humans, animals and mosquitoes. More than 30,000 people have been reported to have fallen sick with the West Nile Virus. Harsh environmental factors have contributed to the spread of WNV. Attempts to curb outbreaks of have solely relied on spraying of mosquitoes. This strategy is contentious because it leads to environmental pollution. Toxic substances in the sprays cause harm, and propagate outbreaks. According to Lipkin, unhealthy environment breaks down immunity of birds and human, making them susceptible to viral infection. This implies that there is a strong relationship between environmental factors, like viruses and toxic substances. Environmental policies instituted aim at protecting, and sustaining the environment. According to Pollution Prevention Act established in November, 1990 stated that pollution should be prevented or minimized at the source wherever possible. Any form of pollution that cannot be prevented should be recycled in a sound manner. Any form of pollution that cannot be prevented or recycled should be treated in a sound manner. Clean Water Act intends to restore and sustain the chemical, physical and biological integrity of water sources. Five elements stand critical in this act. 1- quality standards required for water, discharge permit program, provisions available for special cases of toxic substances and oil spills, national standards for all industries and construction program for publicly-owned treatment works. Limitations for specific pollutants discharged by municipal sewages and industries must be checked (Wilson, Sugg, & Vasavada, 2003). Toxic Substances Control Act emphasizes four issues. Control of toxic substances like testing of chemical substances and mixtures, asbestos Hazard Emergency response, indoor Radon Abatement and Lead Exposure Reduction. II. Project Objectives/Hypothesis, California is one of the states that has been drastically affected by WNV. Surveillance is done regularly through West Nile Watcher to reveals infection rate of WNV in various animals reveals impact of the disease across the state. 2003-2012 WNV ACTIVITY SUMMARY (California Department of Public Health, web). ELEMENT 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 TOTAL Human cases 3 779 880 278 380 445 112 111 158 476 3622 Fatal Human Cases 0 29 19 7 21 15 4 6 9 19 129 Horses 1 540 456 58 28 32 18 19 15 22 1189 Dead birds 96 3232 3046 1446 1396 2569 515 416 688 1644 15048 Mosquito samples 32 1136 1242 832 1007 2003 1063 1305 2087 2849 13556 Sentinel chickens 70 809 1053 640 510 585 443 281 391 540 5322 Squirrels - 49 48 32 26 32 10 24 24 23 268 From the surveillance, the state sought to control the vector borne disease. Since the disease is spread by mosquitoes, the state sought for measures like use of repellants, and massive use of pesticide programs used in other states. This strategy poses a challenge to the environment and remains a controversial issue. Pesticide spraying remains an issue in controlling mosquitoes to prevent spread of WNV. The questions worth considering are; Is it effective in controlling more illness, and environment friendly? III. Methodology The methodology used in the research was imperative questions and data from various research resources. Is spraying of mosquitoes effective? In 2002, a study was done by the Connecticut Agricultural Experiment Station. It was noted from the study that mosquito population never dropped after trucks sprayed pesticides in Greenwich and Stamford. Cage trap experiments have revealed that spraying mosquito reduced their population by 30%. This kind of study overestimates effectiveness of spraying as a remedy. Practically, mosquitoes are not trapped in one place. They hide under leaves in vegetation. This reason extrapolates the trap studies conducted. The insecticide works effectively when it hits the mosquito directly. Spray trucks fog the street side of buildings, giving room of doubt on its effectiveness. Scientist have revealed that less than 0.0001% of ULV (Ultra Low Volume) pesticide spray reaches its target. This implies that hundreds of thousands of droplets circulate pointlessly, leaving only a droplet on the mosquito. A study conducted by CDC reveals that ground application are susceptible to skips and patchy coverage. A study conducted in 1998 showed that more than three times of insecticide was required to kill 90% of mosquitoes in open areas than in in residential areas. This means that high levels of spray is required in residential areas, which is a threat and a violation of safety guidelines. Such like factors decrease the effectiveness of spraying pesticides. The West Nile Virus Advisory Group to Cambridge points out the following factors: Birds are bitten by mosquitoes when at rest. This means that only a few are found in the street during spraying. Roosting areas for mosquitoes are high, hence the spray do not reach them. Structures and trees block the spray from reaching mosquito habors. The spray cannot penetrate backyard roosting areas. The time taken by the spray for effectiveness is short. Further studies from California Mosquito Control Plan states that mosquitoes from Central Valley have developed resistance to organophosphates like malathion (New Hampshire Department of Environmental services 2003). Can pesticide spraying make WNV worse? From the above discussion, spraying of pesticide may make West Nile Virus worse and contribute to other infections. This is supported by these reasons: Resistance developed by mosquitoes due to spraying of pesticides may lead to resurgence of mosquito-borne disease. According to Garret Hardin, every biocide chooses its own mode of failure. According to this statement, mosquitoes develop resistance to chemical strategies that destroy them. It is documented that spraying has contributed to global resurgence in mosquito-borne diseases in the past twenty years. A CDC researcher, Dr. Duane Gubler stated that the technical problems of insecticides and emphasis on killing adult mosquitoes have led to resurgence of diseases. Pesticides kill off natural mosquito predators. Natural predators of mosquitoes and their larvae like fish, arthropods and birds, check population levels. The spray likely destroys these predators and as a result leads to increased mosquito population. In 1997, a study conducted at Cicero Swamp in Central New York State revealed this fact. Population study of mosquitoes responsible for transmitting eastern unique encephalitis (EEE) among birds was done. During the study, the swamp was sprayed fifteen times with an insecticide Dibrom. It was later noted that the population of mosquitoes grew fifteen times. This suggests that the pesticides changed the ecological balance of the swamp by eradicating organisms that limit population of mosquitoes. Pesticides make animals susceptible to WNV infection. The chemicals in the pesticides pose risks to animals and therefore decrease immune system function of animals. This makes them susceptible to diseases. The number of healthy mosquitoes developing encephalitis is increased because of increased chances of biting encephalitis infected animals. Malathion contains impurities and by-products that disrupt the immune system. Immunosuppressant exposes mammalian systems to bacterial, viral, or parasitic infections. This implies that when pesticides are used to control WNV mosquito control, the human and avian immune system will be at a greater risk than before. Risks involved due to public exposure. The general population in urban centers is exposed to the spray. The pesticide has some toxic elements that are inhaled by adults and children as well. IV. Principles for Safe and \Effective Control Measures for Mosquitoes at State and Local Level Offer public health, not pesticides, a benefit of doubt. The threats posed by the use of pesticide must be weighed. Since there is no evidence that spraying limits transmission of diseases, pesticide spraying should not be used to control WNV. Before such a decision is made, environmental and health hazards must be assessed. Indiscriminate use of pesticides must be controlled (Brown, Childs, Durk-Wasser, & Fish 2008). Alternatives to pesticide spraying must be considered to protect public health. Public education, behavioral changes and preventive measures will effectively lower the risk of WNV. Emphasis should be put in source reduction. These involve simple remedies like emptying empty containers, cleaning rain gutters and bird births that involve an individuals approach. The man-made ponds need to be stoked mosquito eating fish, bacterial larvicides or mechanical control methods. The waterways should always be clean to enable survival of other predators like fish. Any vegetation in marshy areas must be cleared so that water is kept flowing. V. Summary and Conclusion Use of pesticide in controlling mosquitoes has not proven successful. The dangers accompanied by this method are weighty and need redress. Before using it as a solution, other remedies must be sought and implemented. The best approach of controlling mosquitoes to avoid spread of WNV is implementation of preventive measures. The larvae stage of the mosquito is the best stage of eradicating or controlling mosquito population. Other preventive measures discussed are environmental friendly but need communal involvement. References Brown, E. H., Childs, E. J., Durk-Wasser, A. M. & Fish, D. (2008). Ecologic Factors Associated with West Nile Virus Transmission, Northeastern United States. Vol. 14, Number 10 October 2008. Retrieved from wwwnc.cdc.gov. California Department of Public Health (no date). Latest West Nile Virus Activity in California. Retrieved from westnile.ca.gov New Hampshire Department of Environmental services (2003). West Nile Virus Environmental Issues. Environmental Fact Sheet. Retrieved from www.des.nh.gov. Wilson, M., Sugg, W., & Vasavada, J. (2003). Overkill: Why Pesticide Spraying for West Nile Virus in California May Cause More Harm Than Good. Pesticide Watch. Retrieved from www.pesticidewatch.org. Read More