Tick Activity Increases with the Return of Spring

This article is adapted from “Hot topics in Epidemiology, April-2014” produced by the Disease Control and Environmental Epidemiology Division of the Colorado Department of Public Health and Environment

Colorado residents who spend time outdoors this spring and early summer should avoid tick bites to prevent some diseases. The primary vector of tick-borne diseases in our state is the Rocky Mountain wood tick, Dermacentor andersoni. The Rocky Mountain wood tick is generally found in sagebrush, juniper and pine habitats in areas that have moderate amounts of shrubs and grasses from elevations of 4,000 to 10,000 feet. The adult tick readily feeds on human blood, and can transmit Colorado tick fever (CTF) and Rocky Mountain spotted fever (RMSF). Cases of CTF are common in Colorado, whereas cases of RMSF are not. CTF is not a reportable condition, but RMSF is.

Adult Rocky Mountain wood ticks usually come out from their overwintering sites beginning in March and tick activity peaks in April. We expect most tick activity to end in June because of hot, dry conditions though this is weather dependent. Ticks wait on grasses and shrubs for animals (or people) to pass by and brush up against the vegetation, than the tick hitches a ride. The tick crawls up until it finds an area of skin to bite. Ticks are often found behind the knees, at the waistband and groin area, around the armpits and at the nape of the neck.

Both CTF virus and the bacteria that causes RMSF are found in rodents in nature. Immature ticks (larvae and nymphs) feed on infected rodents and become infected themselves. Adult ticks will feed on larger animals such as deer and humans. People are at risk of getting sick when an infected adult Rocky Mountain wood tick bites them. Unlike people, rodents and other animals infected by these disease agents do not become sick.

If you are bitten by a tick carrying CTF virus or the RMSF bacteria you may become ill. The time from the tick bite to when symptoms begin can be as short as one to two days, or as long as two weeks. Symptoms for these two diseases are similar, with patients experiencing fever, chills, headache, muscle aches, and lethargy. Less than 20% of people with CTF will have a rash on their body, whereas up to 90% of RMSF patients will have a rash. Many patients with CTF will become better on their own within a few weeks, and there is no treatment because CTF is caused by a virus. Rocky Mountain spotted fever is a more serious disease than CTF, it is caused by bacteria and should be treated with antibiotics as soon as possible. People should consult their healthcare provider if they develop a fever and become ill after a tick bite or after having been in tick habitat. Many people who become ill do not recall being bitten by a tick, so they should be sure to mention that they’ve been in tick habitat even if they don’t think they were bitten by a tick.

Recommendations for avoiding tick bites include using a tick repellent and taking a shower after being outdoors. A factsheet about ticks and tick-borne diseases in Colorado is available from the Colorado State University Extension Office. Additional information from the Centers for Disease Control and Prevention (CDC) about avoiding tick bites can be found here. Information about different tick-borne diseases found in the United States is available from the CDC here.

Spring Cleaning and Hantavirus

Spring season is often a time for cleaning, which is why Jefferson County Public Health reminds everyone that there are some important steps to take to protect against the respiratory disease, Hantavirus Pulmonary Syndrome (HPS). Hantavirus is carried by rodents, most commonly the deer mouse in Colorado. People can get HPS when they are exposed to infected rodents or their urine or droppings. Not all deer mice carry the virus and there is no way to tell if a mouse is infected, thus the best way to prevent HPS is to eliminate or minimize contact with rodents. According to the Centers for Disease Control and Prevention, Hantavirus has a mortality rate of 38% and begins with symptoms of fatigue, fever and muscle aches especially in the large muscle groups—thighs, hips, back, and sometimes shoulders. These symptoms are universal and can begin anytime between 1 to 5 weeks of exposure. JCPH encourages everyone cleaning out garages, sheds, cabins, trailers and other places that have been ignored for most of winter, to keep their eyes open for any evidence that deer mice have been present and to take the necessary precautions.

Hantavirus can be stirred up in dust and breathed in by people. Sweeping up mouse droppings or wiping out areas where rodents have been present can stir the virus into the air where it can be inhaled.

Use the following steps to clean any areas you suspect have been contaminated:

• Use latex, rubber or vinyl gloves and thoroughly wet the areas with a bleach solution or household disinfectant. Spray the urine and droppings with a disinfectant or a mixture of bleach and water and let soak 5 minutes. The recommended concentration of bleach solution is 1 part bleach to 10 parts water.
• Once wet, contaminated materials can be taken up with damp towel and then mopped or sponged with bleach solution or household disinfectant. Contaminated gloves should be disinfected before taking them off. 
• After taking off the clean gloves, wash hands with soap and warm water. 

“These steps are especially important as vacuuming an area without first wetting it down can stir up dust and will not provide the necessary protection against Hantavirus,” said Dave Volkel, JCPH Zoonosis (animal-borne disease) program specialist.

The best way to prevent the risk of Hantavirus infection is to control the presence of rodents in and around the home. JCPH also advises that residents rodent proof their homes by plugging holes and entry points where mice can get inside; eliminating food sources for rodents; and removing abandoned vehicles and wood, brush and junk piles where rodents hide.

• Currently there is not an effective treatment for Hantavirus, so take precaution when cleaning this spring. For more information, please see our Hantavirus webpage or call the Zoonosis Program at 303-271-5700.
• Colorado Department of Public Health and Environment questions and answers: Q & A

Get ACTIVE in April

Spring is officially here and Jefferson County Public Health encourages everyone to make the most of it. Get outside and get active. Physical activity can help improve your health, make a commitment to move more this April! Check out the U.S. Department of Health and Human Services Physical Activity Guidelines and the national “Let’s Move” campaign.