Reportable Disease Data

Infectious diseases are illnesses caused by bacteria, viruses, fungi, or parasites. They can spread through person-to-person contact, contaminated food or water, insect or animal bites, or exposure to infected animals or the environment.

The most commonly reported infectious diseases in Vermont vary from year to year. In 2024, the five most frequently reported diseases were Lyme disease, chlamydia, anaplasmosis, hepatitis C, and campylobacteriosis.

Learn more about infectious diseases and chronic diseases in Vermont.

Not all infectious diseases are required to be reported to public health.

Diseases are typically designated as reportable because they can cause serious illness, spread quickly, lead to outbreaks, or require public health action to protect the community.

Information about reportable diseases helps the Vermont Department of Health:

• Detect and investigate outbreaks.
• Monitor disease trends over time.
• Identify populations at increased risk.
• Guide disease prevention and response efforts.
• Meet state and federal reporting requirements.

Disease rates can vary between communities and groups of people for many reasons. Differences are often influenced by environmental, social, and economic factors—such as access to health care, housing, education, employment, and the environments where people live and work—that affect opportunities for exposure and illness. Looking at these patterns helps public health professionals identify health inequities, understand who may be at greater risk, and guide prevention efforts and resources where they are needed most.

The data in this explorer come from reports submitted to the Vermont Department of Health by healthcare providers, laboratories, and other reporting entities. Use the data to help understand trends in infectious diseases in Vermont. As you explore the data, keep in mind the following limitations:

• Data may change over time as investigations are completed, reports are updated, and additional information becomes available. 

• Data may differ from information published by other sources, including the Centers for Disease Control and Prevention (CDC), because of differences in how the data are calculated and because records may be updated after they are initially shared.

• Reported cases don't represent all illnesses occurring in Vermont. Some people may not seek medical care, receive testing, or receive a diagnosis. As a result, the data may underestimate the true number of infections in the community.

• To protect patient privacy when the number of cases is very small, there may be too few cases to display.