Distribution and Density of Haemaphysalis longicornis (Acari: Ixodidae) on Public Lands in Pennsylvania, United States

Author(s):  
Keith J Price ◽  
Bryn J Witmier ◽  
Rebecca A Eckert ◽  
Christian N Boyer ◽  
Matt W Helwig ◽  
...  

Abstract Since the recent introduction of the Asian longhorned tick (Haemaphysalis longicornis Neumann) in the United States, quantitative surveillance information remains lacking, which hinders accurate estimates of population structure and entomological risk. We conducted statewide, active tick surveillance from May to August 2019 and report data on H. longicornis geographical distribution and population density in Pennsylvania. In total, 615 H. longicornis were collected from four counties. Across samples recovering H. longicornis, mean density of H. longicornis was 9.2/100 m2, comparably greater than Ixodes scapularis Say (8.5/100 m2). Density of H. longicornis was also significantly greater in August, largely driven by larvae, and greater in recreational habitat types (12.6/100 m2) and in Bucks County (11.7/100 m2), situated adjacent to the location of the first U.S. discovery of intense infestations. These data are among the first to document H. longicornis from statewide tick surveillance and provide initial measures of population density enabling more quantitative characterizations of distributional patterns.

2019 ◽  
Author(s):  
Isobel Ronai ◽  
Danielle M. Tufts ◽  
Maria A. Diuk-Wasser

AbstractThe Asian longhorned tick (Haemaphysalis longicornis) was reported for the first time in the United States of America in 2017 and has now spread across 12 states. The potential of this invasive tick vector to transmit pathogens will be determined through its association to native hosts, such as the white-footed mouse (Peromyscus leucopus) which is the primary reservoir for the causative agent of Lyme disease (Borrelia burgdorferi) and other zoonotic pathogens. We placed larval H. longicornis on P. leucopus, 65% of the larvae (n = 40) moved off the host within a short period of time and none engorged. In contrast, larval black-legged ticks (Ixodes scapularis) did not move from where they were placed in the ear of the mouse. We then conducted a laboratory behavioural assay to assess the interaction of H. longicornis with the hair of potential mammalian host species in the United States of America. H. longicornis larvae were less likely to enter the hair zone of P. leucopus and humans compared to the hair of domestic cats, domestic dogs, and white-tailed deer. Our study identifies a tick-host hair interaction behaviour, which can be quantified in a laboratory assay to predict tick-host associations and provides insights into how ticks select a host.


Author(s):  
Daniel C Mathisson ◽  
Sara M Kross ◽  
Matthew I Palmer ◽  
Maria A Diuk-Wasser

Abstract Tick-borne illnesses have been on the rise in the United States, with reported cases up sharply in the past two decades. In this literature review, we synthesize the available research on the relationship between vegetation and tick abundance for four tick species in the northeastern United States that are of potential medical importance to humans. The blacklegged tick (Ixodes scapularis) (Say; Acari: Ixodidae) is found to be positively associated with closed canopy forests and dense vegetation thickets, and negatively associated with open canopy environments, such as grasslands or old agricultural fields. The American dog tick (Dermacentor variabilis) (Say; Acari: Ixodidae) has little habitat overlap with I. scapularis, with abundance highest in grasses and open-canopy fields. The lone star tick (Amblyomma americanum) (Linnaeus; Acari: Ixodidae) is a habitat generalist without consistent associations with particular types of vegetation. The habitat associations of the recently introduced Asian longhorned tick (Haemaphysalis longicornis) (Neumann; Acari: Ixodidae) in the northeastern United States, and in other regions where it has invaded, are still unknown, although based on studies in its native range, it is likely to be found in grasslands and open-canopy habitats.


2019 ◽  
Vol 109 (5) ◽  
pp. 878-886 ◽  
Author(s):  
Milton T. Drott ◽  
Lauren M. Fessler ◽  
Michael G. Milgroom

Consumption of food contaminated with aflatoxin, from crops infected by Aspergillus flavus, is associated with acute toxicosis, cancer, and stunted growth. Although such contamination is more common in the lower latitudes of the United States, it is unclear whether this pattern is associated with differences in the relative frequencies of aflatoxigenic individuals of A. flavus. To determine whether the frequency of the aflatoxin-producing ability of A. flavus increases as latitude decreases, we sampled 281 isolates from field soils in two north-south transects in the United States and tested them for aflatoxin production. We also genotyped 161 isolates using 10 microsatellite markers to assess population structure. Although the population density of A. flavus was highest at lower latitudes, there was no difference in the frequency of aflatoxigenic A. flavus isolates in relation to latitude. We found that the U.S. population of A. flavus is subdivided into two genetically differentiated subpopulations that are not associated with the chemotype or geographic origin of the isolates. The two populations differ markedly in allelic and genotypic diversity. The less diverse population is more abundant and may represent a clonal lineage derived from the more diverse population. Overall, increased aflatoxin contamination in lower latitudes may be explained partially by differences in the population density of A. flavus, not genetic population structure.


Author(s):  
Nicholas P Piedmonte ◽  
Vanessa C Vinci ◽  
Thomas J Daniels ◽  
Bryon P Backenson ◽  
Richard C Falco

Abstract The Asian longhorned tick, Haemaphysalis longicornis Neumann, is a species native to eastern Asia that has recently been discovered in the United States. In its native range, H. longicornis transmits pathogens that cause disease in humans and livestock. It is currently unknown whether H. longicornis will act as a vector in the United States. Understanding its seasonal activity patterns will be important in identifying which times of the year represent greatest potential risk to humans and livestock should this species become a threat to animal or public health. A study site was established in Yonkers, NY near the residence associated with the first reported human bite from H. longicornis in the United States. Ticks were collected once each week from July 2018 to November 2019. Haemaphysalis longicornis larvae were most active from August to November, nymphs from April to July, and adult females from June to September. This pattern of activity suggests that H. longicornis is capable of completing a generation within a single year and matches the patterns observed in its other ranges in the northern hemisphere. The data presented here contribute to a growing database for H. longicornis phenology in the northeastern United States. Potential implications of the short life cycle for the tick’s vectorial capacity are discussed.


2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Brittany L Schappach ◽  
Rayda K Krell ◽  
Victoria L Hornbostel ◽  
Neeta P Connally

Abstract The Asian longhorned tick (ALT), Haemaphysalis longicornis Neumann (Acari: Ixodidae), is a three-host tick that was first detected outside of United States Department of Agriculture (USDA) quarantine in Hunterdon County, New Jersey, in 2017 and subsequently found in another 14 states. In its native Asia, and where it has become established in Australia and New Zealand, ALTs feed on a variety of hosts and are economically important livestock pests and competent vectors of multiple pathogens to humans and other animals. The degree to which ALT will become a persistent livestock pest or competent vector for introduced or existing pathogens in the United States is yet unclear. Because of its vast host availability, ability to reproduce asexually, known vector competence, and the presence of multiple life stages on hosts, the expansion of ALT establishment in the United States is expected, and is a significant public health and veterinary concern. In this paper, we discuss the biology, geographical distribution, life cycle and seasonal activity, reproduction, identification, medical and veterinary implications, management options, and future concerns in the United States.


2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Kristen L. Knapp ◽  
Nancy A. Rice

Borrelia burgdorferi, the causative agent of Lyme disease, andBabesia microti, a causative agent of babesiosis, are increasingly implicated in the growing tick-borne disease burden in the northeastern United States. These pathogens are transmitted via the bite of an infected tick vector,Ixodes scapularis, which is capable of harboring and inoculating a host with multiple pathogens simultaneously. Clinical presentation of the diseases is heterogeneous and ranges from mild flu-like symptoms to near-fatal cardiac arrhythmias. While the reason for the variability is not known, the possibility exists that concomitant infection with bothB. burgdorferiandB. microtimay synergistically increase disease severity. In an effort to clarify the current state of understanding regarding coinfection withB. burgdorferiandB. microti, in this review, we discuss the geographical distribution and pathogenesis of Lyme disease and babesiosis in the United States, the immunological response of humans toB. burgdorferiorB. microtiinfection, the existing knowledge regarding coinfection disease pathology, and critical factors that have led to ambiguity in the literature regarding coinfection, in order to eliminate confusion in future experimental design and investigation.


2021 ◽  
Author(s):  
Danielle M Tufts ◽  
Maria A Diuk-Wasser

Abstract Invasive arthropod vectors and the range expansions of native vectors can lead to public and veterinary health concerns, as these vectors may introduce novel pathogens or spread endemic pathogens to new locations. Recent tick invasions and range expansion in the United States has been attributed to climate and land use change, an increase in global travel, and importations of exotic animals. A 10 year surveillance study was conducted on Block Island, Rhode Island from 2010–2020 including sampling ticks from small mammal and avian hosts. We report the discovery and establishment of the red sheep tick for the first time in the western hemisphere and in the United States. This invasive species was first collected in 2010 on Block Island, was collected continuously throughout the study, and was collected from an avian host. We document the first report of the invasive Asian longhorned tick in the state of Rhode Island, first observed at our sites in 2018. Finally, we present data on the range expansion and establishment of two native tick species, the lone star tick and the rabbit tick on Block Island. This study emphasized the importance of long-term surveillance to detect changes in tick host communities, including invasive and expanding native vectors of potential significance to humans and wildlife.


Author(s):  
Niayesh Afshordi ◽  
Benjamin Holder ◽  
Mohammad Bahrami ◽  
Daniel Lichtblau

The SARS-CoV-2 pandemic has caused significant mortality and morbidity worldwide, sparing almost no community. As the disease will likely remain a threat for years to come, an understanding of the precise influences of human demographics and settlement, as well as the dynamic factors of climate, susceptible depletion, and intervention, on the spread of localized epidemics will be vital for mounting an effective response. We consider the entire set of local epidemics in the United States; a broad selection of demographic, population density, and climate factors; and local mobility data, tracking social distancing interventions, to determine the key factors driving the spread and containment of the virus. Assuming first a linear model for the rate of exponential growth (or decay) in cases/mortality, we find that population-weighted density, humidity, and median age dominate the dynamics of growth and decline, once interventions are accounted for. A focus on distinct metropolitan areas suggests that some locales benefited from the timing of a nearly simultaneous nationwide shutdown, and/or the regional climate conditions in mid-March; while others suffered significant outbreaks prior to intervention. Using a first-principles model of the infection spread, we then develop predictions for the impact of the relaxation of social distancing and local climate conditions. A few regions, where a significant fraction of the population was infected, show evidence that the epidemic has partially resolved via depletion of the susceptible population (i.e., “herd immunity”), while most regions in the United States remain overwhelmingly susceptible. These results will be important for optimal management of intervention strategies, which can be facilitated using our online dashboard.


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