Inadequacy of IgM antibody tests for diagnosis of Rocky Mountain Spotted Fever.

Among 13 suspected Rocky Mountain spotted fever (RMSF) cases identified through an enhanced surveillance program in Tennessee, antibodies to Rickettsia rickettsii were detected in 10 (77%) patients using a standard indirect immunofluorescent antibody (IFA) assay. Immunoglobulin M (IgM) antibodies were observed for 6 of 13 patients (46%) without a corresponding development of IgG, and for 3 of 10 patients (30%) at least 1 year post-onset. However, recent infection with a spotted fever group rickettsiae could not be confirmed for any patient, based on a lack of rising antibody titers in properly timed acute and convalescent serologic specimens, and negative findings by polymerase chain reaction testing. Case definitions used in national surveillance programs lack specificity and may capture cases that do not represent current rickettsial infections. Use of IgM antibodies should be reconsidered as a basis for diagnosis and public health reporting of RMSF and other spotted fever group rickettsiae in the United States.

Knowledge, attitudes, and practices regarding Rocky Mountain spotted fever among healthcare providers, Tennessee, 2009.

Tennessee has a high incidence of Rocky Mountain spotted fever (RMSF), the most severe tick-borne rickettsial illness in the United States. Some regions in Tennessee have reported increased illness severity and death. Healthcare providers in all regions of Tennessee were surveyed to assess knowledge, attitudes, and perceptions regarding RMSF. Providers were sent a questionnaire regarding knowledge of treatment, diagnosis, and public health reporting awareness. Responses were compared by region of practice within the state, specialty, and degree. A high proportion of respondents were unaware that doxycycline is the treatment of choice in children ≤ 8 years of age. Physicians practicing in emergency medicine, internal medicine, and family medicine; and nurse practitioners, physician assistants, and providers practicing for < 20 years demonstrated less knowledge regarding RMSF. The gaps in knowledge identified between specialties, designations, and years of experience can help target education regarding RMSF.

Emergence of a new pathogenic Ehrlichia species, Wisconsin and Minnesota, 2009.

BACKGROUND: Ehrlichiosis is a clinically important, emerging zoonosis. Only Ehrlichia chaffeensis and E. ewingii have been thought to cause ehrlichiosis in humans in the United States. Patients with suspected ehrlichiosis routinely undergo testing to ensure proper diagnosis and to ascertain the cause. METHODS: We used molecular methods, culturing, and serologic testing to diagnose and ascertain the cause of cases of ehrlichiosis. RESULTS: On testing, four cases of ehrlichiosis in Minnesota or Wisconsin were found not to be from E. chaffeensis or E. ewingii and instead to be caused by a newly discovered ehrlichia species. All patients had fever, malaise, headache, and lymphopenia; three had thrombocytopenia; and two had elevated liver-enzyme levels. All recovered after receiving doxycycline treatment. At least 17 of 697 Ixodes scapularis ticks collected in Minnesota or Wisconsin were positive for the same ehrlichia species on polymerase-chain-reaction testing. Genetic analyses revealed that this new ehrlichia species is closely related to E. muris. CONCLUSIONS: We report a new ehrlichia species in Minnesota and Wisconsin and provide supportive clinical, epidemiologic, culture, DNA-sequence, and vector data. Physicians need to be aware of this newly discovered close relative of E. muris to ensure appropriate testing, treatment, and regional surveillance. (Funded by the National Institutes of Health and the Centers for Disease Control and Prevention.).

Supporting business continuity during a highly pathogenic avian influenza outbreak: a collaboration of industry, academia, and government.

Since 2006, a collaborative group of egg industry, state, federal, and academia representatives have worked to enhance preparedness in highly pathogenic avian influenza (HPAI) planning. The collaborative group has created a draft egg product movement protocol, which calls for realistic, science-based contingency plans, biosecurity assessments, commodity risk assessments, and real-time reverse transcriptase-PCR testing to support the continuity of egg operations while also preventing and eradicating an HPAI outbreak. The work done by this group serves as an example of how industry, government, and academia can work together to achieve better preparedness in the event of an animal health emergency. In addition, in the event of an HPAI outbreak in domestic poultry, U.S. consumers will be assured that their egg products come from healthy chickens.

Murine typhus in Austin, Texas, USA, 2008.

In August 2008, Texas authorities and the Centers for Disease Control and Prevention investigated reports of increased numbers of febrile rash illnesses in Austin to confirm the causative agent as Rickettsia typhi, to assess the outbreak magnitude and illness severity, and to identify potential animal reservoirs and peridomestic factors that may have contributed to disease emergence. Thirty-three human cases of confirmed murine typhus were identified. Illness onset was reported from March to October. No patients died, but 23 (70%) were hospitalized. The case-patients clustered geographically in central Austin; 12 (36%) resided in a single ZIP code area. Specimens from wildlife and domestic animals near case-patient homes were assessed; 18% of cats, 44% of dogs, and 71% of opossums had antibodies reactive to R. typhi. No evidence of R. typhi was detected in the whole blood, tissue, or arthropod specimens tested. These findings suggest that an R. typhi cycle involving opossums and domestic animals may be present in Austin.

Flea-associated zoonotic diseases of cats in the USA: bartonellosis, flea-borne rickettsioses, and plague.

Cat-scratch disease, flea-borne typhus, and plague are three flea-associated zoonoses of cats of concern in the USA. Although flea concentrations may be heaviest in coastal and temperate climates, fleas and flea-borne disease agents can occur almost anywhere in the USA. Understanding flea-borne pathogens, and the associated risks for owners and veterinarians, is important to reduce the likelihood of zoonotic infection.