Communicable Diseases & Conditions

The Gallatin City-County Health Department’s Communicable Disease Program works to prevent, identify, and limit the spread of those diseases that can be passed from one person to another. Working together with area health care providers, our team investigates and tracks individual cases to prevent them from spreading further. We also aim to determine the source of an infection, identify contacts, and provide education to the general public.


What is a communicable disease?

A communicable disease is defined as an infectious disease that can be transmitted between persons and species through either direct or indirect transmission or other vectors (animals & insects.)



Zika Virus

Guidance and information on Zika is constantly changing. For the latest information, check out the CDC’s webpage:

As of July 22, 2016, there were three cases of Zika in Montana and all were travelers to Zika affected countries. Here are five things that the CDC wants people to know about Zika virus:

  1. Zika is primarily spread through infected mosquitos, but you can also get the virus through sex. Montana is one of several states that does not have the type of mosquito that can spread Zika. The Aedes species of mosquito is common to tropical, subtropical, and temperate climates, making it common to southern states and Latin America. It is also possible for someone infected with Zika to pass the virus to their partner(s) through sex.
  2. The best way to prevent Zika is to prevent mosquito bites. Some ways to do this are: use EPA-registered insect repellent, wear long-sleeved shirts and long pants, stay in places with air conditioning or window/door screens, and remove standing water around your home.
  3. Zika is linked to birth defects, particularly microcephaly which hinders brain development in utero. If you are pregnant and have a partner who lives in or has traveled to an area with Zika, do not have sex, or use condoms the right way, every time, during your pregnancy.
  4. Additionally, pregnant women should not travel to areas with Zika. If you must travel to a Zika affected area, talk to your health care provider before leaving and follow steps to prevent mosquito bites during your trip.
  5. Returning travelers infected with Zika can spread the virus through mosquito bites. Zika virus can stay in your blood for about a week, which means if an Aedes species mosquito bites you during that time, the virus can be passed to the mosquito. The infected mosquito can then bite other people and infect them with Zika virus.



Two incubation periods have passed without any new cases of mumps. We hope the outbreak, which affected 21 people in Belgrade, is now over. Gallatin City-County Health Department would like to thank Belgrade schools and the community for working with us and helping contain the outbreak. We hypothesize that the outbreak could have been much larger if not for the high level of vaccine protection within Belgrade schools.

Mumps is a viral disease characterized by swelling of the parotid or salivary glands along the face, neck, and jaw. The swelling can last from two to ten days. The incubation period (the time from when you were infected to when you have symptoms) is 12-25 days. Other symptoms, in addition to the swelling around the neck and jaw, include fever, malaise (tiredness), muscle aches, and headache. Call your healthcare provider if you think your child is showing symptoms of mumps.



Some communicable diseases in our community include:

Pertussis (Whooping Cough)


• Hepatitis

Sexually Transmitted Diseases (STDs)

Strep Throat

Food & Waterborne Illnesses


Tick Born Illnesses



For more information on these and other communicable diseases, see


To see what has been reported this week, check out our weekly reports for Gallatin County.


Click to see the reportable communicable diseases in Montana 1995-2015.



Are you a health care provider needing to report a confirmed or suspect case of a communicable disease?  Please call 406-582-3100.

If you need to reach the Gallatin City-County Health Dept after hours to report an urgent public health matter, call the Gallatin County Sheriff’s office at 582-2100, ext. 2