Dr. Stafford Tick Management Handbook - Newtown, CT
Dr. Stafford Tick Management Handbook - Newtown, CT
Dr. Stafford Tick Management Handbook - Newtown, CT
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<strong>Stafford</strong>The Connecticut Agricultural Experimentation Stationquinolones such as cipro. oxacin as well as streptomycin and gentamicin. While tetracycline orchloramphenicol also may be used, they are less effective and relapses occur more frequently.Powassan EncephalitisPowassan virus, a Flavivirus, is the sole member of the tick-borne encephalitis (TBE) grouppresent in North America. The disease is named after a town in Ontario, Canada where it was . rstisolated and described from a fatal case of encephalitis in 1958. Documented cases of Powassanencephalitis (POW) are rare, but the disease may be more common than previously realized. Whilethere were only 27 known cases in North America between 1958-1998 (mainly in Canada andNew York state), four additional cases were identi. ed in Maine and Vermont from 1999-2001 asa result of increased testing for West Nile virus. Surface antigens of these two viruses are similar,thus allowing cross-reactivity in antibody testing. The ages of these recent New England casesranged from 25 to 70 years. Previously, the latest recognized symptomatic cases occurred in NewYork in 1978 and Massachusetts in 1994. POW presents as meningitis or meningoencephalitisprogressing to encephalitis with fever, convulsions, headache, disorientation, lethargy, with partialcoma and paralysis in some patients. The disease has a fatality rate of 10-15% and may result insevere long-term disability in the survivors. The principal tick vector appears to be Ixodes cookeiwith cases occurring from May through October. Patients generally have a history of tick bite, or ahistory of exposure to tick habitat or exposure to hosts such as squirrels, skunks, or woodchucks.The blacklegged tick is a competent vector of Powassan virus in the laboratory. A virus veryclosely related to and apparently a separate subtype of the Powassan virus has been isolated from I.scapularis, but the prevalence and public health signi. cance of this virus are unknown.<strong>Tick</strong>-borne Relapsing FeverSoft ticks of the genus Ornithodoros transmit relapsing fever, caused by Borrelia hermsi, ora group of tick-adapted strains of the spirochete. Disease is characterized by cycles of high feverand is treated with antibiotics. Relapsing fever ticks are found in rodent burrows, nests, and cavesthrough the western United States. They can live for many years without feeding. Human cases areoften associated with people staying in shelters or cabins infested with these ticks.Colorado <strong>Tick</strong> FeverColorado tick fever, caused by a virus, occurs in mountainous areas of the western United Statesand Canada. There are 200-400 cases each year. Scientists believe that cases are underreported.The virus is transmitted by female Rocky Mountain wood ticks. Symptoms begin with an acutehigh fever, often followed by a brief remission, and another bout of fever lasting 2-3 days. Othersymptoms included severe headache, chills, fatigue, and muscle pain. Illness may be mild to severe,but is self-limited and not fatal. Treatment is symptomatic. Recovery occurs over several weeks butoccasionally may take months.Bartonella InfectionThe genus Bartonella includes at least 16 species of vector-associated, blood-borne bacteria thatinfect a wide variety of domestic and wild animals, including rodents. Several are known humanpathogens. These cause cat scratch disease (B. henselae), trench fever (B. quintana), Oroya fever(B. bacilliformis), and endocarditis (B. elizabethae). For example, Bartonella henselae, the agentof cat scratch disease, is transmitted to cats by . eas and generally to humans by bites or scratchesfrom infected cats. Bartonella-speci. c DNA has been detected in I. scapularis and I. pacificusticks, clearly ingested during feeding. A high percentage of I. ricinus ticks in Europe also have beenreported to be infected with Bartonella henselae. A novel Bartonella species has been found with B.burgdorferi and B. microti in the white-footed mouse. At this time, there is no convincing evidenceBulletin No. 1010 33