Animal-Related (Zoonotic) Diseases

The Tri-County Health Department will dissolve completely as of December 31, 2022.  On January 1, 2023, Arapahoe, Adams and Douglas Counties will provide public health services through their own, individually operated health departments. 

Douglas County residents only:  Effective September 1, 2022, the newly created Douglas County Health Department will assume responsibility for all Environmental Health services in Douglas County.  Starting September 1, 2022 please direct all questions/concerns related to Environmental Health to the Douglas County Health Department by calling 720 643 2400 or by visiting: 

Animal-related (zoonotic) diseases are diseases that affect both humans and animals. We protect residents from bacterial and viral diseases transmitted by mammals, mosquitos, ticks, and fleas. Some of these diseases have long been present in the State of Colorado while others have recently emerged. These diseases are hantavirus, plague, rabies, tularemia, and West Nile virus.

Zoonotic Diseases 

Rabies is a fatal but preventable viral disease. It can spread to people and pets if they are bitten or scratched by a rabid animal. Rabies is mostly found in wild animals like bats, raccoons, skunks, and foxes. Read more from the CDC, or download our fact sheets in English and Spanish.

Hantavirus affects the lungs and is spread to people by infected rodents, especially the deer mouse. Infection can lead to a serious complication that is fatal about 40% of the time. Read more from the CDC, or download our fact sheets in English and Spanish

Plague is a disease that affects humans and other mammals and is caused a bacterium. Humans usually get plague after being bitten by a rodent flea that is carrying the bacterium, or by handling an animal infected with plague. Read more from the CDC, or download our fact sheet in English and Spanish

Tularemia is caused by a bacterium. Also known as “rabbit fever,” tularemia is most often found in rabbits, rodents, and hares, and can be carried by ticks, deer flies, horse flies, and mosquitoes. Read more from the CDC, or read our FAQs on Tularemia and Rabbits. You can also download our factsheets in both English and Spanish

West Nile virus is spread by the bite of an infected mosquito. There are no medications to treat West Nile virus in people. While many who are infected do not feel sick, about 1 in 5 develop a fever and other symptoms. About 1 out of 150 infected people develop a serious, sometimes fatal, illness. Read more from the CDC, or download our fact sheets in English and Spanish.

Reporting a Dead Animal

To report a dead animal, complete and submit our form for reporting a dead animal or call your local Environmental Health office.

It is not uncommon to find dead animals or birds. Animals and birds die every day from natural causes, predators, or disease. It is important to report such findings to your local health department so that they can be documented and a decision made to determine if a test is necessary to determine if the cause of death is associated with a zoonotic disease. 

Reporting Diseases

By law, certain diseases must be reported to public health agencies from health care providers and laboratories in order to keep the illness from spreading. These diseases are referred to as Reportable Diseases.