Vector-Borne Diseases

There has been a worldwide resurgence of vector-borne diseases since the 1970s including malaria, dengue, Yellow fever, louse-borne typhus, plague, leishmaniasis, sleeping sickness, West Nile encephalitis, Lyme disease, Japanese encephalitis, Rift Valley fever, and Crimean-Congo hemorrhagic fever. Reasons for the emergence or resurgence of vector-borne diseases include the development of insecticide and drug resistance; decreased resources for surveillance, prevention and control of vectorborne diseases; deterioration of the public health infrastructure required to deal with these diseases; unprecedented population growth; uncontrolled urbanization; changes in agricultural practices; deforestation; and increased travel. Changes have been documented in the distribution of important arthropod disease vectors. The yellow fever mosquito, Aedes aegypti has reestablished in parts of the Americas where it had been presumed to have been eradicated; the Asian tiger mosquito, Aedes albopictus, was introduced into the Americas in the 1980s and has spread to Central and South America; and the blacklegged tick, Ixodes scapularis, an important transmitter of Lyme disease and other pathogens, has gradually expanded its range in parts of eastern and central North America.

Tick-Borne Diseases | CDC/NIOSH

Overview

Tick-borne pathogens can be passed to humans by the bite of infected ticks. Ticks can be infected with bacteria, viruses, or parasites. Some of the most common tick-borne diseases in the United States include: Lyme disease, babesiosis, ehrlichiosis, Rocky Mountain Spotted Fever, anaplasmosis, Southern Tick-Associated Rash Illness, Tick-Borne Relapsing Fever, and tularemia. Other tick-borne diseases in the United States include: Colorado tick fever, Powassan encephalitis, and Q fever. Lyme disease is the most commonly reported tick-borne disease in the United States. In 2008, nearly 29,000 confirmed cases of Lyme disease were reported to the Centers for Disease Control and Prevention (CDC).

Outdoor workers are at risk of exposure to tick-borne diseases if they work at sites with ticks. Worksites with woods, bushes, high grass, or leaf litter are likely to have more ticks. Outdoor workers in most regions of the United States should be extra careful to protect themselves in the spring, summer, and fall when ticks are most active. Ticks may be active all year in some regions with warmer weather.

Frequently Asked Questions

Which workers are at risk of infection?

All outdoor workers should check with their supervisor if they have questions about possible exposure to ticks. Workers at risk of tick-borne diseases include, but are not limited to, those working in the following:

• Construction
• Landscaping
• Forestry
• Brush clearing
• Land surveying
• Farming
• Railroad work
• Oil field work
• Utility line work
• Park or wildlife management
• Other outdoor work

What diseases are transmitted by ticks in the United States?

Diseases caused by tick-borne pathogens in the United States include:

• Lyme disease
• Babesiosis
• Ehrlichiosis
• Rocky Mountain Spotted Fever
• Southern Tick-Associated Rash Illness
• Tick-Borne Relapsing Fever
• Tularemia
• Anaplasmosis
• Colorado tick fever
• Powassan encephalitis
• Q fever

Where are infected ticks found in the United States?

Tick-Borne Disease	Common US Regions
Lyme disease	Northeast, North Central, Pacific Coast
Babesiosis	Northeast, Midwest, Northwest
Ehrlichiosis	East, Southeast, Central
Rocky Mountain Spotted Fever	Southeast, Atlantic Coast
Southern Tick-Associated Rash Illness	Southeast, Atlantic Coast
Tick-Borne Relapsing Fever	Rocky Mountains, Pacific Coast
Tularemia	All States except Hawaii
Anaplasmosis	Northeast, North Central, Pacific Coast
Colorado Tick Fever	Northwest, Rocky Mountains
Powassan Encephalitis	Northeast
Q fever	Throughout the United States

When are workers at risk of infection?

Ticks are usually more active in the months of April through October and peak in the summer months of June through August. The time of year when ticks are active may vary with the geographic region and climate. Outdoor workers should be extra careful to protect themselves in the late spring and summer when immature ticks are most active.

What are the symptoms of infection with a tick-borne disease?

There are many symptoms associated with tick-borne diseases. Infected workers may not have all of these symptoms and many of these symptoms can occur with other diseases as well. Some common symptoms of infection with tick-borne diseases include:

• Body/muscle aches
• Fever
• Headaches
• Fatigue
• Joint pain
• Rash
• Stiff neck
• Facial paralysis

What is the diagnosis and treatment for tick-borne diseases?

Tick-borne diseases are diagnosed based on symptoms and the possibility that the worker has been exposed to infected ticks.

Most cases can be successfully treated with specific types of antibiotics, especially if treatment is started early. However, some workers may have symptoms such as arthritis, muscle and joint pain, or fatigue for an extended period of time.

Recommendations for Employers

Employers should protect their workers from tick-borne diseases by taking these steps:

• Provide training for workers that includes information about the following:
• How tick-borne diseases are spread
• The risks of exposure and infection
• How workers can protect themselves from ticks
• The importance of the timely reporting of workplace illnesses and injuries
• Recommend that workers wear light-colored long-sleeved shirts, long pants, socks, and hat when possible.
• If worker uniforms are provided, provide long-sleeved shirts and long pants as options.
• Provide workers with repellents (containing 20% to 30% DEET) to use on their skin and clothing for protection against tick bites.
• Provide workers with repellents (such as Permethrin) to provide greater protection. Permethrin kills ticks on contact. It can be used on clothing but not skin.
• When possible, have workers avoid working at sites with woods, bushes, tall grass, and leaf litter.
• When avoiding these sites is not possible, personal protective measures are of particular importance. If work in these higher-risk sites must occur, take the following steps to reduce tick populations:
• Remove leaf litter.
• Remove, mow, or cut back tall grass and brush.
• Discourage deer activity.

Images courtesy of CDC Public Health Image Library, CDC Division of Viral and Rickettsial Diseases and the CDC Division of Vector-Borne Infectious Diseases

Tick Bite fever of dogs

Tick Bite fever of dogs