Environmental Risks

Environmental health risks are conditions in the environment that can adversely affect human health and quality of life. These risks may arise from exposure to air and water pollution, hazardous chemicals, extreme heat, unsafe food, and inadequate sanitation or waste management. Left unaddressed, environmental health risks can contribute to acute illness, chronic disease, and increased vulnerability during emergencies. Proactive monitoring, regulation, and community education are essential to reducing these risks and protecting public health.

Major Environmental Hazards

Dengue is a mosquito-borne viral disease transmitted by the Aedes aegypti mosquito. While most dengue infections are asymptomatic or mild, severe illness and, in rare cases, death can occur. Preventing and controlling dengue focuses on reducing mosquito populations and minimizing exposure. Key strategies include eliminating standing water around homes and businesses, using fogging or spraying when appropriate, and practicing personal protection measures such as wearing long-sleeved clothing, applying mosquito repellents containing DEET, and using mosquito netting or window screens.

Foodborne Disease. Foodborne illnesses are caused by viruses, bacteria, parasites, toxins, metals, and prions (microscopic protein particles). Symptoms range from mild gastroenteritis to life-threatening neurologic, hepatic, and renal syndromes.

Hantavirus. Hantaviruses are transmitted to humans from the dried droppings, urine, or saliva of mice and rats. Animal laboratory workers and persons working in infested buildings are at increased risk of this disease.

Legionnaires' Disease. Legionnaires' disease is a bacterial disease commonly associated with water-based aerosols. It is often the result of poorly maintained air conditioning cooling towers and potable water systems.

Marburg virus disease is a severe hemorrhagic fever caused by the Marburg virus, transmitted to humans through contact with infected animals, bodily fluids, or contaminated surfaces. Symptoms include sudden onset of fever, severe headache, muscle aches, followed by vomiting, diarrhea, bleeding, and organ failure in severe cases. Prevention relies on avoiding exposure to infected individuals or wildlife, using appropriate personal protective equipment, and following strict infection prevention and control practices.

 Rabies in humans is caused by the rabies virus, usually transmitted through bites from infected animals. Symptoms include fever, headache, confusion, and paralysis, and it is almost always fatal once symptoms appear. Prevention includes vaccination of pets, avoiding wild animals, and post-exposure prophylaxis after bites.

Rocky Mountain Spotted Fever (Spotted Fever Rickettsiosis) is caused by Rickettsia rickettsii bacteria transmitted via tick bites. Symptoms include fever, rash, headache, and muscle pain. Early treatment with antibiotics is critical. Prevention focuses on avoiding tick exposure and using repellents.

Tularemia. Tularemia is a disease that can infect animals and people. Rabbits, hares, and rodents are especially susceptible and often die in large numbers during outbreaks. People can become infected in several ways, including tick and deer fly bites, skin contact with infected animals, consuming contaminated water, inhaling contaminated aerosols or agricultural and landscaping dust, or laboratory exposure.  People could also be exposed as a result of bioterrorism.

West Nile virus is a mosquito-borne disease most commonly spread through the bite of infected mosquitoes. While most people experience no symptoms, some may develop flu-like illness, and in rare cases, severe neurological disease. Prevention focuses on reducing mosquito breeding sites and using personal protective measures such as insect repellent and protective clothing.

Zika Virus. The Zika virus is most commonly spread through the bites of infected mosquitoes in areas with ongoing viral transmission. However, it can also be passed from person to person through sharps injuries (e.g., needlesticks) and other exposures to infectious blood, body fluids, and materials. Outdoor workers in areas with active transmission, along with those in laboratories handling samples of the Zika virus, remain at the greatest risk of infection.

Yellow fever is caused by a virus transmitted by infected mosquitoes. Symptoms include fever, jaundice, muscle pain, and, in severe cases, organ failure. Prevention includes vaccination and mosquito control measures, such as repellents and bed nets.

Amebic encephalitis caused by Naegleria fowleri is a rare but often fatal brain infection that occurs when warm freshwater containing the amoeba enters the body through the nose. Early symptoms may include headache, fever, nausea, and vomiting, followed by stiff neck, confusion, seizures, and coma. Prevention includes avoiding nasal exposure to warm freshwater, using nose clips or keeping the head above water during freshwater activities, and using properly treated water for nasal rinsing.