Zoonoses are animal diseases that can be transmitted to humans.  Most newly discovered viruses that have infected people have evolved from animals. Little is known about why some viruses can cross species barriers and then spread widely, while others do not.

Recent zoonoses of concern include Avian Influenza, Lyme Disease, Rabies, and West Nile Virus.  Illnesses that result from food contamination with E. coli 0157:H7 and Salmonella may also fit into this category. Attention to these zoonotic diseases has prompted a more widespread appreciation of the need for ongoing, effective surveillance of animal diseases and communication between the veterinary, medical and public health communities.

Insect Repellent: Use and Effectiveness – an interactive tool developed by the Environmental Protection Agency (EPA) to assist in selecting repellents to guard against mosquito and tick-borne illness.

 Zoonotic Diseases of Concern

Avian Influenza (Bird Flu)

Avian influenza (AI) is a highly contagious viral disease of birds caused by type A strains of the influenza virus. Fifteen subtypes of the Type A influenza virus are known to infect birds, with all severe outbreaks to date caused by subtypes H5 and H7. AI was first identified in Italy more than 100 years ago and all birds are thought to be susceptible to infection with varying levels of resistance. Migratory waterfowl, particularly ducks, are quite resistant and a frequent reservoir of infection. They can cause epidemics when they come in contact with susceptible domestic poultry species such as chickens and turkey.  The disease can have serious socioeconomic consequences, causing major losses to the poultry industry and disrupting international trade in live poultry and poultry products. Non-commercial bird species are also susceptible.

Public Health Threat: The current outbreak of subtype H5N1 has raised international public health concern because the bird flu has jumped to people and other mammals, causing serious illness and death. The disease caused by avian influenza A (H5N1) virus infection in humans differs from that usually caused by influenza viruses, where respiratory symptoms are dominant. H5N1 influenza has the ability to affect multiple organs, causing high mortality.

Transmission: Direct contact with infected birds appears to be the main source of infection for humans.

Lyme Disease

Lyme disease is caused by a bacteria that is transmitted by the deer tick and can affect anyone at any age. People who spend time in grassy and wooded environments are at an increased risk of contracting this disease. Symptoms will appear within 3-30 days of the bite from an infected tick and include a bull’s eye rash around the site of the bite, chills and fever, headache, fatigue, stiff neck, joint pain, and swollen glands. If untreated, Lyme disease may progress to arthritis, or heart and central nervous system problems.

Precautionary measures: Wear light-colored clothing, long pants, sleeves when walking in grassy or wooded areas.  The use of a tick repellent is a personal decision. Check the body for ticks and remove them with tweezers as close as possible to where the tick is attached to the skin. The early removal of the tick reduces the risk for infection and antibiotics are used to treat Lyme disease in its early stages.

West Nile Virus

West Nile Virus (WNV) is a mosquito-borne virus that is primarily a disease of birds, but humans and other animals (horses, in particular) can also be infected. First detected in 1999 in New York State, most people infected will have no symptoms and about 20% will experience mild symptoms which include fever, headache and body aches. People over the age of 50 are at higher risk for developing serious diseases such as encephalitis or meningitis. There is no vaccine available, so prevention of mosquito bites and elimination of mosquito breeding areas are important measures to reduce the potential for infection.