Epidemiology and Spatial Emergence of Anaplasmosis, New York, USA, 2010‒2018

Abstract

A naplasmosis is an emergent tickborne disease caused by the obligate intracellular bacterium Anaplasma phagocytophilum (1). Initially termed human granulocytic ehrlichiosis, human infection with A. phagocytophilum was fi rst described in 1994 in patients from Minnesota and Wisconsin, USA (1,2). Now referred to as human granulocytic anaplasmosis or simply anaplasmosis, this infection is characterized by a nonspecifi c infl uenza-like illness marked by fever, fatigue, muscle aches, and headache (3). Although severe complications and death occur in rare instances, most patients recover fully after treatment with appropriate antimicrobial drugs (4).Human infection with A. phagocytophilum has now been documented in patients in North America, Europe, and Asia, and a notable incidence has occurred in the United States (5). Anaplasmosis became a nationally notifi able disease in the United States during 1999, and nationwide case counts have since increased >16-fold, from 348 cases during 2000 to 5,762 cases during 2017 (6). Most of these infections occur in the northeastern and upper midwestern states, where well-established populations of Ixodes scapularis (blacklegged or deer ticks) transmit A. phagocytophilum in addition to the infectious agents of Lyme disease, babesiosis, and Powassan virus disease (7-9).New York State (NYS), which is situated within the northeastern United States, to which tickborne diseases are endemic, has reported the second highest number of anaplasmosis cases of any state, closely behind Minnesota (10-12). Surveillance of anaplasmosis cases by the NYS Department of Health (NYSDOH) indicates that since the fi rst NYS case was reported in 1994, the burden of anaplasmosis has increased substantially, accounting for a larger proportion of NYS tickborne disease cases every year (≈4% during 2010 vs. ≈11% during 2018) (13). Since 2015, anaplasmosis has consistently surpassed babesiosis as the second most common tickborne disease in NYS, after Lyme disease (13). In addition to surveillance of tickborne disease cases, the NYSDOH also conducts routine vector surveillance to monitor the dynamics of tick populations and the prevalence of tickborne pathogens, including A. phagocytophilum, to estimate

Associations ofAnaplasma phagocytophilumBacteria Variants inIxodes scapularisTicks and Humans, New York, USA

“…Anaplasmosis incidence was significantly correlated with Ap-ha ERI in I. scapularis adults for all 9 years analyzed, whereas 6 of the 9 years analyzed were correlated for I. scapularis nymphs ( Table 3 ). Statistically significant correlation coefficients in I. scapularis adults were 0.36–0.75, an increase in the minimum and maximum correlation coefficients compared with non–variant-specific PCR results ( 13 ). Statistically significant correlation coefficients in I. scapularis nymphs were 0.19–0.68, a decrease in the minimum coefficient and an increase in the maximum coefficient compared with correlations calculated using the non–variant-specific PCR results ( 13 ).…”

“…We tested the Spearman rank correlation between mean Ap-ha ERI in I. scapularis nymphs and adults and anaplasmosis incidence at the postal (ZIP) code tabulation area level gathered from the New York State Department of Health (NYSDOH) Communicable Disease Electronic Surveillance system as previously described ( 13 ). We assessed the correlation for each year, 2010–2018.…”

“…We corrected the 18 correlation tests for multiple testing using the Bonferroni-Holm adjustment ( 24 ). We compared results of the Spearman rank tests with the results from a previous analysis using non–genotype-specific A. phagocytophilum ERI ( 13 ).…”

“…We also used a scan statistic to search for spatiotemporal clusters of Ap-ha and Ap-V1 in New York tick populations for 2008–2020. We then compared spatiotemporal clusters of Ap-ha and Ap-V1 in I. scapularis ticks to documented regions of increased anaplasmosis incidence in New York over the same timeframe ( 13 , 15 ). The results help to illuminate the relationship between the spatial ecology of each variant and the outcome of human disease.…”

Neurological Pain, Psychological Symptoms, and Diagnostic Struggles among Patients with Tick-Borne Diseases

“…Fatigue is a classic presentation in anaplasmosis, with other non-specific influenza-like symptoms, such as fever, fatigue, muscle aches, and headaches. [129,130] Babesiosis presents with typical clinical symptoms that include the following: fever, fatigue, malaise, weakness, chills, sweats, and headaches. [131] The CDC reports fatigue as present in the following TBDs: Borrelia miyamotoi, babesiosis, Colorado tick fever, Heartland virus disease, and tularemia.…”