Employees often encounter wildlife hazards when working outdoors. Far too often, however, the risks associated with the tiny mosquito are overlooked. Beyond itchy bites, these insects can cause illness and spread diseases, which may even be fatal. It is imperative to understand how to identify these bugs, the damage that they can cause and how to reduce the likelihood of being bitten.

Mosquitoes and diseases

Mosquitoes live in areas such as forests, grasslands and marshes, always near standing water. This means that encounters with these insects are inevitable, especially those  frequenting the outdoors. There are two types of mosquitoes: permanent water and floodwater mosquitoes. 

The permanent water variety lay their eggs in permanent to semipermanent bodies of water such as lakes, ponds, swamps, marshes and even containers that hold water. 

According to the Centers for Disease Control and Prevention (CDC), “Floodwater mosquitoes lay their eggs in moist soil or in containers above the water line. The eggs dry out, then hatch when rain floods the soil or container.” Their habitats may include temporary pools and ponds created by melting snow or rain; floodplains along streams and riverbanks; irrigated fields and meadows; containers that fill up after rain; or tree holes that collect rainwater.

Only female mosquitoes bite people and animals to feed on their blood, which they need to lay eggs and reproduce. When one bites, it punctures the skin of the host. While the mosquito is feeding, it injects saliva into the skin, causing a red, inflamed bump and itching. 

Most mosquito bites only result in a minor reaction, which can be treated by washing the area with soap and water, applying ice to decrease swelling or using a mixture of baking soda and water, over-the-counter anti-itch or antihistamine cream to reduce itching. 

Some mosquitoes carry viruses and other diseases that can be transmitted to humans. Female mosquitoes carry arthropod-borne viruses, called arboviruses. Globally, these include Chikungunya, Dengue, West Nile, yellow fever, Zika and malaria. These illnesses should be taken seriously, as the Occupational Safety and Health Administration has issued interim guidance on West Nile and Zika viruses. 

In the United States, the most concerning mosquito-transmitted virus is malaria. According to the World Health Organization, “It is a life-threatening disease primarily found in tropical countries. It is both preventable and curable. However, without prompt diagnosis and effective treatment, a case of uncomplicated malaria can progress to a severe form of the disease, which is often fatal without treatment.” It is not contagious or transmissible from person to person.

In June, the CDC issued a Health Alert Network Health Advisory to share information and notify clinicians, public health authorities and the public that, for the first time in 20 years, malaria cases were reported on American soil. The cases occurred in Florida and Texas. 

Symptoms of malaria usually appear 10–15 days after being infected. Initially, they include fever, headache and chills. They can progress rapidly to multi-organ failure and even death. Children may also experience severe anemia, respiratory distress or cerebral malaria. If malaria is suspected, medical treatment should be sought immediately. A blood test can determine the result. 

Staying safe on the job

In an effort to minimize mosquito encounters or bites, remove standing water from rain gutters, old tires, buckets, plastic covers and any other object or container where mosquitoes breed. Additionally, repellents, pesticides and structural barriers such as netting or screens can be used in mosquito-prone areas.

According to the EPA’ “Tips to Prevent Mosquito Bites”: 

• Keep mosquitoes away from exposed skin by wearing long-sleeved shirts, long pants, and socks.
• Tuck shirts into pants and pants into socks to cover gaps in your clothing where mosquitoes can get to your skin.
• Stay indoors when possible, especially if there is a mosquito­-borne disease warning in effect. 
• Use EPA-registered mosquito repellents and follow label directions and precautions closely. 
• Use head nets, long sleeves and long pants if you venture into areas with high mosquito populations, such as salt marshes. 
• Replace your outdoor lights with yellow “bug” lights, which tend to attract fewer mosquitoes than ordinary lights.