Five Years’ Experience With the Novel Human Ehrlichia Sp. In the Upper Midwestern United States: 2009-2013.

We recently discovered a novel human pathogen closely related to Ehrlichia muris detected using PCR, culture, and serology in clinical specimens from Minnesota and Wisconsin (Pritt et al., N. Engl. J. Med. 2011). We now present our 5 years’ experience (2009-2013) of human infections with this bacterium. Blood from patients with suspected ehrlichiosis or anaplasmosis was tested using PCR targeting the Ehrlichia/Anaplasma GroEL Heat Shock Operon gene. Epidemiologic data was gathered using a standardized questionnaire. During 6/1/2009-8/19/2013, blood from 30 MN and 28 WI patients tested PCR positive for this new Ehrlichia sp. This result was also detected in residents from North Dakota (3), Indiana (1) and Michigan (1) with recent travel to WI or MN (total cases=63). Patient specimens (n=11,046) from 44 other states tested negative. The Ehrlichia sp. was cultured from the blood of one WI patient. Patients comprised 40 men and 23 women, ages 23 - 94 years (median=62 years). Among patients with available data, infection manifested with fever (53/60), headache (40/57), lymphopenia (16/28), and thrombocytopenia (28/43); 11 of 48 were hospitalized (3-15 days, median 4 days) and 55 received doxycycline treatment and made a full recovery, while one patient recovered without treatment. Treatment or outcome data were unavailable for 7 patients. Conclusion: The novel Ehrlichia sp. appears to circulate in a region where ehrlichiae have not historically been known to be endemic and causes a disease which is clinically similar to human monocytic ehrlichiosis due to E. chaffeensis and anaplasmosis due to Anaplasma phagocytophilum. These findings should be taken into consideration for diagnosis and surveillance in residents or individuals with travel to MN and WI states

Novel \u3cem\u3eEhrlichia\u3c/em\u3e sp. Pathogenic for Humans in the Midwestern United States: Human Cases 2009 - 2011 and Results of Tick, Rodent, and Deer Studies

We recently reported a novel Ehrlichia sp. closely related to E. muris detected in blood of 4 from patients in Minnesota (MN) and Wisconsin (WI) in 2009 (NEJM 2011). We now present data from the 2009-2011 patient cases, and results of tick, rodent, and deer studies. Blood from patients with suspected ehrlichiosis or anaplasmosis was tested using PCR targeting the Ehrlichia/Anaplasma Heat Shock Operon gene. PCR was also performed on rodent and deer blood, ticks from MN and WI, and ticks found on military personnel at 132 U.S. military bases nationwide (2007-2010). Select specimens were characterized using culture and DNA sequencing. Human sera were tested for antibodies to specific Ehrlichia spp. and A. phagocytophilum. During 6/2009-8/2011, blood from 32 of 8,110 MN and WI patients tested PCR positive for an Ehrlichia sp. other than E. chaffeensis and E. ewingii. This result was also detected from 1 North Dakota patient who recently travelled to MN. The result was not noted among 7,827 other patient specimens from other states. An Ehrlichia sp. was also cultured from the blood of one WI patient. The 16S rRNA gene (rrs) sequence of clinical and culture isolates was most similar to E. muris (98%). Patients comprised 22 men and 11 women, aged 23 - 87 years. Among patients with available data, infection manifested with fever (31/33), headache (26/33) lymphopenia (7/12) and thrombocytopenia (14/19); 4 of 33 were hospitalized (≤3 days) and 32 of 33 recovered following doxycycline treatment. One patient recovered without treatment. Three of 3 patients had a higher antibody titer to the novel Ehrlichia sp. than E. chaffeensis. No antibodies to A. phagocytophilum antigens were detected. Thirty-four of 1,384 I. scapularis ticks from MN and WI were PCR positive for the novel Ehrlichia, whereas it was not detected in I. scapularis from other states (n=2931) or other tick species (n=6563). Two of 147 rodents and 0 of 180 deer tested were PCR positive. Based on these data, the novel Ehrlichia sp. appears to circulate in a region where Ehrlichiae have not historically been considered endemic and causes a disease which is clinically and epidemiologically similar to human monocytic ehrlichiosis due to E. chaffeensis. These findings should be taken into consideration for diagnosis and surveillance

Behavioral thermoregulation and slowed migration by adult fall Chinook salmon in response to high Columbia River water temperatures

The relationships between lower Columbia River water temperatures and migration rates, temporary tributary use, and run timing of adult fall Chinook salmon Oncorhynchus tshawytscha were studied using historical counts at dams and recently collected radiotelemetry data. The results from more than 2,100 upriver bright fall Chinook salmon radio-tagged over 6 years (1998, 2000-2004) showed that mean and median migration rates through the lower Columbia River slowed significantly when water temperatures were above about 20 degrees C. Slowed migration was strongly associated with temporary use of tributaries, which averaged 2-7 degrees C cooler than the main stem. The proportion of radio-tagged salmon using tributaries increased exponentially as Columbia River temperatures rose within the year, and use was highest in the warmest years. The historical passage data showed significant shifts in fall Chinook salmon run timing distributions concomitant with Columbia River warming and consistent with increasing use of thermal refugia. Collectively, these observations suggest that Columbia River fall Chinook salmon predictably alter their migration behaviors in response to elevated temperatures. Coolwater tributaries appear to represent critical habitat areas in warm years, and we recommend that both main-stem thermal characteristics and areas of refuge be considered when establishing regulations to protect summer and fall migrants