Associations of Anaplasma phagocytophilum Bacteria Variants in Ixodes scapularis Ticks and Humans, New York, USA.

Anaplasmosis, caused by the tickborne bacterium Anaplasma phagocytophilum, is an emerging public health threat in the United States. In the northeastern United States, the blacklegged tick (Ixodes scapularis) transmits the human pathogenic genetic variant of A. phagocytophilum (Ap-ha) and a nonpathogenic variant (Ap-V1). New York has recently experienced a rapid and geographically focused increase in cases of anaplasmosis. We analyzed A. phagocytophilum-infected I. scapularis ticks collected across New York during 2008-2020 to differentiate between variants and calculate an entomological risk index (ERI) for each. Ap-ha ERI varied between regions and increased in all regions during the final years of the study. Space-time scan analyses detected expanding clusters of Ap-ha located within documented anaplasmosis hotspots. Ap-ha ERI was more positively correlated with anaplasmosis incidence than non-genotyped A. phagocytophilum ERI. Our findings help elucidate the relationship between the spatial ecology of A. phagocytophilum variants and anaplasmosis.

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

Human granulocytic anaplasmosis, a tickborne disease caused by the bacterium Anaplasma phagocytophilum, was first identified during 1994 and is now an emerging public health threat in the United States. New York state (NYS) has experienced a recent increase in the incidence of anaplasmosis. We analyzed human case surveillance and tick surveillance data collected by the NYS Department of Health for spatiotemporal patterns of disease emergence. We describe the epidemiology and growing incidence of anaplasmosis cases reported during 2010-2018. Spatial analysis showed an expanding hot spot of anaplasmosis in the Capital Region, where incidence increased >8-fold. The prevalence of A. phagocytophilum increased greatly within tick populations in the Capital Region over the same period, and entomologic risk factors were correlated with disease incidence at a local level. These results indicate that anaplasmosis is rapidly emerging in a geographically focused area of NYS, likely driven by localized changes in exposure risk.

Predicting spatio-temporal population patterns of Borrelia burgdorferi, the Lyme disease pathogen.

The causative bacterium of Lyme disease, Borrelia burgdorferi, expanded from an undetected human pathogen into the etiologic agent of the most common vector-borne disease in the United States over the last several decades. Systematic field collections of the tick vector reveal increases in the geographic range and prevalence of B. burgdorferi-infected ticks that coincided with increases in human Lyme disease incidence across New York State.We investigate the impact of environmental features on the population dynamics of B. burgdorferi. Analytical models developed using field collections of nearly 19,000 nymphal Ixodes scapularis and spatially and temporally explicit environmental features accurately explained the variation in the nymphal infection prevalence of B. burgdorferi across space and time.Importantly, the model identified environmental features reflecting landscape ecology, vertebrate hosts, climatic metrics, climate anomalies and surveillance efforts that can be used to predict the biogeographical patterns of B. burgdorferi-infected ticks into future years and in previously unsampled areas.Forecasting the distribution and prevalence of a pathogen at fine geographic scales offers a powerful strategy to mitigate a serious public health threat. Synthesis and applications. A decade of environmental and tick data was collected to create a model that accurately predicts the infection prevalence of Borrelia burgdorferi over space and time. This predictive model can be extrapolated to create a high-resolution risk map of the Lyme disease pathogen for future years that offers an inexpensive approach to improve both ecological management and public health strategies to mitigate disease risk.

A Comparative Spatial and Climate Analysis of Human Granulocytic Anaplasmosis and Human Babesiosis in New York State (2013-2018).

Human granulocytic anaplasmosis (HGA) and human babesiosis are tick-borne diseases spread by the blacklegged tick (Ixodes scapularis Say, Acari: Ixodidae) and are the result of infection with Anaplasma phagocytophilum and Babesia microti, respectively. In New York State (NYS), incidence rates of these diseases increased concordantly until around 2013, when rates of HGA began to increase more rapidly than human babesiosis, and the spatial extent of the diseases diverged. Surveillance data of tick-borne pathogens (2007 to 2018) and reported human cases of HGA (n = 4,297) and human babesiosis (n = 2,986) (2013-2018) from the New York State Department of Health (NYSDOH) showed a positive association between the presence/temporal emergence of each pathogen and rates of disease in surrounding areas. Incidence rates of HGA were higher than human babesiosis among White and non-Hispanic/non-Latino individuals, as well as all age and sex groups. Human babesiosis exhibited higher rates among non-White individuals. Climate, weather, and landscape data were used to build a spatially weighted zero-inflated negative binomial (ZINB) model to examine and compare associations between the environment and rates of HGA and human babesiosis. HGA and human babesiosis ZINB models indicated similar associations with forest cover, forest land cover change, and winter minimum temperature; and differing associations with elevation, urban land cover change, and winter precipitation. These results indicate that tick-borne disease ecology varies between pathogens spread by I. scapularis.

Twenty years of surveillance for Eastern equine encephalitis virus in mosquitoes in New York State from 1993 to 2012.

BACKGROUND: The year 1971 was the first time in New York State (NYS) that Eastern equine encephalitis virus (EEEV) was identified in mosquitoes, in Culiseta melanura and Culiseta morsitans. At that time, state and county health departments began surveillance for EEEV in mosquitoes. METHODS: From 1993 to 2012, county health departments continued voluntary participation with the state health department in mosquito and arbovirus surveillance. Adult female mosquitoes were trapped, identified, and pooled. Mosquito pools were tested for EEEV by Vero cell culture each of the twenty years. Beginning in 2000, mosquito extracts and cell culture supernatant were tested by reverse transcriptase-polymerase chain reaction (RT-PCR). RESULTS: During the years 1993 to 2012, EEEV was identified in: Culiseta melanura, Culiseta morsitans, Coquillettidia perturbans, Aedes canadensis (Ochlerotatus canadensis), Aedes vexans, Anopheles punctipennis, Anopheles quadrimaculatus, Psorophora ferox, Culex salinarius, and Culex pipiens-restuans group. EEEV was detected in 427 adult mosquito pools of 107,156 pools tested totaling 3.96 million mosquitoes. Detections of EEEV occurred in three geographical regions of NYS: Sullivan County, Suffolk County, and the contiguous counties of Madison, Oneida, Onondaga and Oswego. Detections of EEEV in mosquitoes occurred every year from 2003 to 2012, inclusive. EEEV was not detected in 1995, and 1998 to 2002, inclusive. CONCLUSIONS: This was the first time in NYS that EEEV was detected in Cx. salinarius, Ps. ferox and An. punctipennis. The detection of EEEV in mosquitoes every year for 10 years was the longest time span since surveillance began in 1971. The calendar date of the earliest annual appearance of EEEV in mosquitoes did not change during surveillance spanning 42 years.

The first record of larval collections of Ochlerotatus thibaulti in New York state.

Larvae of Ochlerotatus thibaulti Dyar and Knab have not been reported in New York State or New England, but adult records suggest that breeding populations are present. In 2003 and 2004, larval Oc. thibaulti were collected at 3 sites upstate near the Catskill Mountain region in Lomontville, NY. This is the 1st record of Oc. thibaulti collected in New York and New England. Larvae were found in a variety of subterranean habitats within and near semipermanent woodland pools, including under hummocks and in deep and shallow depressions of upturned trees. No immatures were observed after late June. Larvae of Culiseta melanura were found in the same habitats in the early spring and later in the season after Oc. thibaulti had emerged.

Field evaluation of CDC gravid trap attractants to primary West Nile virus vectors, Culex mosquitoes in New York State.

A field study was conducted to evaluate two CDC gravid trap attractants available for the West Nile virus surveillance program in New York State (NYS). According to potential attractiveness, a common lawn sod in NYS, Kentucky bluegrass (Poa pratensis) infusion and a rabbit chow infusion were compared for attractiveness to primary West Nile virus vectors, Culex mosquitoes. Attractiveness of each infusion was measured by the number of adult mosquitoes caught in CDC gravid traps and the number of egg rafts laid in ovitraps. Both gravid trap and ovitrap studies demonstrated that lawn sod infusion with a 7-day incubation period had better attractiveness to Culex restuans/Culex pipiens than rabbit chow infusion with the same incubation period. Attractiveness of lawn sod infusions was increased as they became aged within a week's period. Lawn sod infusion also attracted more Ochlerotatus japonicus, a potentially important West Nile virus vector in New York.

Toxorhynchites rutilus septentrionalis: new occurrences in upstate New York.

Records of Toxorhynchites rutilus septentrionalis findings in New York State are few, and collections north of New York City are rare. This is the 1st official documentation of Tx. rutilus found in upstate New York in the past 46 years and the farthest northern record. In 2002, immatures of Tx. rutilus were found in artificial containers in 2 locations in the Hudson Valley region, at Quarryville (Ulster County) and Blauvelt (Rockland County), NY. A study conducted at Quarryville in 2002 and 2003 found that breeding occurred continuously through the season, and that overwintering possibly could be occurring at that site.