JOURNAL OF THE LOUISIANA STATE MEDICAL SOCIETY
States, but it was withdrawn from the market in 2002 because of poor sales. Immunization strategies to prevent tickborne infectious diseases have proved far more effective in Europe and Asia than in the United States, where neurologic complications from TBEVs are second only to Japanese encephalitis virus as causes of permanent paraparesis and flaccid paralysis. As noted, current immunization programs for tickborne viral diseases now provide primary prevention of TBEV-Eu in Europe, TBEV- Sib in Russia and the Middle East, TBEV-FE in China and the Far East, and CCHF in Bulgaria. A canine antitoxin for I. holocyclus – induced tick paralysis has been used to reverse tick paralysis in animals and humans in Australia. 12 In addition to immunization, available only for Old World TBEVs, antibiotic therapy after presumed ixodid tick bites with erythema migrans has been recommended as a prophylactic therapeutic strategy for the primary prevention of some tickborne infections. 11 A randomized clinical trial found that a single 200-mg dose of doxycycline administered within 72 hours of a tick bite was 87% effective in preventing Lyme disease. 11 Finally, because most tickborne infectious diseases may also be transmitted by blood product transfusions, screening blood product donors in high seroprevalence areas for Lyme disease and other borrelioses, babesiosis, ehrlichioses, and anaplasmosis would eliminate transfusion-transmitted cases. 13-15 Physicians are encouraged to order leukocyte-reduced blood components for blood product transfusions to potentially reduce the risks for ehrlichiosis and anaplasmosis, especially in regions that are highly endemic for leukocytotropic tickborne infectious diseases. Personal protective measures to prevent tick-transmitted diseases include wearing appropriate clothing, using insect repellents, and performing regular tick checks. Wearing long pants tucked into socks, long-sleeved shirts, and light-colored clothing can help keep ticks off the skin and make them easier to spot on clothing. Impregnating clothing with permethrin, routinely performed by the military on wilderness maneuvers, is a highly effective repellent against ticks and other insects. The topical application of insect repellents containing 20- 50% formulations of N, N -diethyl-meta-toluamide (DEET) or 20% picaridin directly on the skin is another effective and recommended measure. Most patients with Lyme disease, tickborne relapsing fever (TBRF), babesiosis, ehrlichioses, and anaplasmosis will not recall tick bites because these diseases are often transmitted by diminutive nymphal ticks. Nevertheless, tick localization and removal as soon as possible, remain recommended strategies to prevent the rickettsial and viral ixodid tickborne diseases and to reverse tick paralysis. Ticks should always be removed with forceps (or tweezers), not fingers (because squashing ticks can transmit several tickborne diseases across dermal barriers or create infectious aerosols), and in contiguity with their feeding mouth parts, rather than burning ticks with spent matches or painting embedded ticks with adhesives or nail polishes.
Landscape management strategies to prevent tickborne diseases include widespread application of acaricides over tick-preferred ecosystems, removal of brush and leaf litter near homes and recreation sites, and creation of dry barriers of gravel, stone, rubber, or wood chips between forested areas and yards or playgrounds. Wildlife management strategies to prevent tickborne diseases include encouraging the development of better veterinary vaccines for tickborne diseases with large domestic animal reservoirs, applying acaricides actively to domestic animals and passively to deer, cattle, and other ungulates at baited feeding and watering stations or salt licks, and setting out acaricide-baited rodent houses for rodents to occupy or acaricide-baited cotton or fabric balls for rodents to adopt as nesting materials, especially in crawl spaces under homes, attics and basements, and near playgrounds.
CONCLUSIONS
Most emerging infectious diseases today, such as West Nile virus and severe acute respiratory syndrome virus, arise from zoonotic reservoirs, and many are transmitted by arthropod vectors. Because ticks are the most common insect vectors of zoonotic diseases, ticks have become common arthropod vectors of emerging zoonotic diseases, including tickborne viral diseases, such as deer tick virus and Powassan virus, and bacterial diseases, such as Lyme disease, ehrlichiosis, and anaplasmosis. Ticks are highly competent and versatile vectors of infectious diseases because ticks of all ages and both genders may remain infectious for generations, without having to reacquire infections from their zoonotic host reservoirs. Recent environmental changesandhumanbehaviorsnowplacehumans and ticks together outdoors for longer periods in welcoming ecosystems for breeding, blood-feeding, and infectious disease transmission. Better prevention and treatment strategies for tickborne diseases are indicated, before the highly conserved genomes of tick-transmitted microorganisms re-assort their nucleic acids with their zoonotic and human accidental hosts and develop antimicrobial resistances (especially to doxycycline and ribavirin).
52 J La State Med Soc VOL 170 MARCH/APRIL 2018
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