When it comes to running a business, all factors that could potentially affect its success need to be considered. One such factor is employee safety and with that in mind the risk of West Nile viral encephalitis (WNV) to employee health, should be assessed.
WNV affects people in different ways. The majority of people experience no symptoms whatsoever (4 out of 5 persons). Some people will only experience mild symptoms such as fever, head and muscle aches, and possibly swollen glands. The remainder (1 in 150 persons) will react more severely to the virus experiencing coma and convulsions, with death sometimes resulting.
Biting female mosquitoes, with various species of Culex, Aedes, and Anopheles mosquitoes being the most common vectors in North America, transmit WNV. These mosquitoes breed within roadside and parking lot catch basins, pools of stagnant water, and potentially within any object that can hold water. One or several of these habitats are usually found within the business setting; similarly these habitats are also common around homes. While suitable habitat and vectoring mosquito species may exist in your region, the real threat exists only when the virus is present within local mosquito and bird populations. Birds are the natural host for WNV with transmission occurring when a mosquito feeds on an infected bird and then feed on a human.
The key to determining what actions should be taken to prepare for next years WNV season may be revealed by activity trends in previous years. Infection rates are tallied by the Centers for Disease Control (CDC) and the Public Health Agency of Canada each year. These infection rates should be reviewed for both your immediate state or province, and the region in which you run your business. Activity in neighbouring regions should also be assessed as it may give a more accurate picture of what is on the horizon. For North America, WNV first appeared in the New York Metropolitan area of the United States in the summer 1999 and has spread out in all directions from there. In general, provinces and states further from the origin appear to be on the upswing for WNV cases while those locations closer to the origin are on the decline.
Regions of North America that are facing an upswing in WNV cases need to plan for the implementation of an aggressive and thorough mosquito control program. Components of such a program could vary and depending on the severity of risk, should include:
Educating employees about the WNV and how to protect themselves from contracting it (wearing mosquito repellents, wearing protective clothing, avoiding mosquitoes by remaining indoors during peak mosquito activity times);
An assessment and regular inspection of the property to identify standing water;
Monitoring and regular larviciding of catch basins;
Installation of mosquito traps along the perimeter of the property to intercept mosquitoes; and
Residual spraying and fogging of mosquito harbourage sites such as shrubs and plants near the building.
If you are in a location that has already weathered the storm you may be able to down size your mosquito control program and therefore reduce your operating budget. As with other viruses, people that have been exposed to a WNV build antibodies that help protect them against future illness from the current viral strain. Areas that have experienced heavy WNV activity over previous years are having dramatically fewer cases now. This may also be in part due to existing regional mosquito control programs suppressing the mosquito population and virus transmission. In this situation a less intensive approach to mosquito control may be adequate. Your control program should continue to focus on employee education, elimination of sources of standing water, and regular monitoring and prescribed treatment of catch basins and standing water.
By assessing your individual situation and taking the appropriate action, you should be able to greatly enhance the safety of your business environment, protecting your valuable employees against WNV.