Dr. Paul Auerbach is the world's leading outdoor health expert. His blog offers tips on outdoor safety and advice on how to handle wilderness emergencies.See all posts »
A Newly-Recognized Tick Borne Illness
In the New England Journal of Medicine (2012;367:834-41), there is an article by Laura McMullan, Ph.D. and colleagues entitled “A New Phlebovirus Associated with Severe Febrile Illness in Missouri.” Two men from northwestern Missouri are described who independently came to a medical facility with symptoms of fever, fatigue, diarrhea, low platelet (blood-clotting components) count, and low white blood cell count. Both men had been bitten by ticks 5 to 7 days prior to the onset of their illnesses. Although Ehrlichia chaffeensis was suspected as the causative agent of their illnesses, it turned out to be novel viruses of the phlebovirus genus.
Phleboviruses have been noted before in sand flies, mosquitoes, and ticks. As noted by the authors, an example of a mosquito-borne phlebovirus is Rift Valley fever virus. The only tick-borne phlebovirus known to cause human disease was recently identified in central and northeastern China. Thus, this association with tick bite in the U.S. is the first of its kind in our country.
The men had a number of manifestations of their illness, including elevated liver enzyme levels, very low platelet counts, low white blood cell counts, mild electrolyte abnormalities, loss of appetite, and transient short-term memory loss.
The authors are naming this new virus the “Heartland virus.” Symptoms that were common to both patients were fever, fatigue, loss of appetite, and diarrhea. Common laboratory abnormalities were low white blood cell counts, low platelet counts, and elevated liver enzymes. They recommend that physicians be on the lookout for this infection when someone is ill, offers a history of tick bite, and does not respond after a few days to the antibiotic doxycycline given in anticipation of treating an ehrlichiosis infection. The authors suspect the lone star tick Amblyomma americanum as a possible vector, but this was not proven.
Here is information about tick avoidance:
When traveling in forests and fields, it is a good idea to inspect the body thoroughly (particularly the hairline, groin, underarms, navel, scalp, and other hair-covered areas) for ticks each day. Don’t forget to brush ticks out of the fur of all dogs and pack animals.
Wear proper clothing to prevent tick attachment. Ticks have a more difficult time attaching to smooth, tightly woven fabrics. Keep shirts tucked into pants and trouser cuffs tucked into socks. Light-colored clothing displays ticks. If clothing is worn loosely fitting, it will not be pulled close to the skin, and it will be more difficult for a tick or insect to bite through and reach the skin. If mesh clothing or a head net is deployed, the mesh size should be less than 0.3 mm. Wear a light-colored, broad-brimmed hat to protect the head and neck. If ticks are seen on clothing, they may be removed by trapping them on a piece of cellophane tape or using a sticky tape lint roller device. Unless a hot cycle in a clothing dryer is employed, washing clothing may not remove tick nymphs. The deer tick, which transmits the infectious agent of Lyme disease, is extremely small, particularly in juvenile stages. The best repellent is permethrin (Permanone) applied to clothing, not to skin, but DEET is also effective.
At home, keep grass trimmed short. Remove thick piles of grass and leaves. Remove brush from woodpiles and areas adjacent to dwellings. Keep the woodpiles distant. Don’t tempt deer to approach your dwelling by landscaping with plants that are tasty. If you have pets (particularly dogs that can hide ticks in their fur), inspect them regularly, particularly if they have access to wooded areas or have been along with you on a hike. Use veterinarian-approved pesticide sprays, powders, treatments and tick collars.
Wood chips, mulch, and gravel do not tend to harbor ticks, so can be used against wooden fences, under sandboxes and playgrounds, or to create borders adjacent to tick habitat. Apply a perimeter of pesticides around the perimeter of your property. Mice and chipmunks carry fleas, so discourage their presence.
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