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CDC EIS Officers Presented Emerging Vector-borne Disease Research at Recent Conference

Ian D. Plumb, MD, and his group studied an unusual cluster of endocarditis due to Bartonella quintana, which is transmitted to humans by body lice and prevalent among people who are homeless, in Anchorage, Alaska. The authors reviewed the charts of patients with Bartonella infection in Anchorage hospitals from 2009 through 2014; and since August 2015, they collected lice from clothing of patients examined at one emergency department, and performed PCR for Bartonella using 2 molecular targets (gltA and ITS). They identified 7 cases confirmed by PCR from 2012 through 2014-5, 2 with positive serology only. All occurred in men over 40, including 6 Anchorage residents, 4 homeless, 3 who used the same shelter, and 3 with louse infestation. Six had valvular cardiac failure and 2 died. All surviving patients needed valve replacement and antimicrobial therapy. Of 55 lice collected from 21 patients to date, 4 lice from 2 patients tested positive for B. quintana. The authors recommend Bartonella testing in men with possible lice exposure and unexplained valvular insufficiency and they called for more research.
Heather Venkat, DVM, MPH, and her colleagues evaluated a BioSense syndrome-based query for West Nile Virus (WNV). They found that the platform used by the Arizona Department of Health Services (ADHS) was too broad to reveal trends for this leading cause of domestically acquired arboviral disease in the United States which can lead to neuroinvasive disease and death.
The authors recorded hospital emergency department and inpatient visits over ten months in 2015 and chief complaints or diagnoses of: fever, chills, headache, rash, vertigo, muscle pain, joint pain, nausea, vomiting, stiff neck, altered mental status, seizures, limb or muscle weakness, encephalitis, or loss of consciousness. They compared WNV BioSense cases with reported lab-confirmed WNV cases and identified the correlations between WNV BioSense and reported WNV cases.
Searching for 2 or more symptoms detected 141,920 WNV BioSense cases, 3 or more symptoms detected 38,093 cases, and 4 or more symptoms detected 5,790 cases. By contrast, 91 lab-confirmed WNV cases were reported. The correlation between trends of WNV BioSense cases with 2 or more WNV symptoms and lab-confirmed WNV cases was not significant (F-test=0.92; P=0.43), and the authors suggested adding more subtle distinctions, weighted criteria, and more hospital involvement to better predict outbreaks.
“For Rickettsia species and other tickborne diseases, there is disease in more of the state than expected. Tick disease is traveling westward,” Jessica A. Nadeau, PhD, MPH, said in her talk about her group’s study of spotted fever group Rickettsia (SFGR) in Kansas. Overall, 83% of persons were considered to be exposed while in their county of residence and 17% exposed while traveling to another county in the state. In 2012 through 2015, most ill persons were in the eastern portion of the state.
The researchers evaluated human SFGR cases reported to the Kansas Department of Health and Environment with onset between January 2012 and October 2015 and canine specimens submitted to the Kansas State Veterinary Diagnostic Laboratory during the same period. Lab tests dates for positive human SFGR serologic tests and positive canine SFGR serologic or polymerase chain reaction tests were compared to determine the first reported case for each county.
Exposure for 514 reported human cases occurred in 58 of the 105 Kansas counties, and in 17 counties for 90 cases in dogs. Exposure for human and canine cases was detected in 14 counties, with dog cases preceding human cases in 4 counties, by an average of 4 months; and canine cases were found in 3 counties with no reported human cases.
“Due to the high mortality of some Rickettsia species, treatment with doxycycline both for non-pregnant adults and children should be started prior to receiving results of confirmatory testing. Due to lack of in-office testing and ease of treatment, many dogs may receive doxycycline empirically without confirmatory testing,” Dr. Nadeau said, and she advised identifying counties at risk to help target tick-borne disease prevention.

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