Exotic Grass Invasion Reduces Survival of <I>Amblyomma americanum</I> and <I>Dermacentor variabilis</I> Ticks (Acari: Ixodidae)

Abstract Tick-borne diseases (TBD) in humans have dramatically increased over recent years and although the bulk of cases are attributable to Lyme Disease in the Northeastern US, TBDs like spotted fever rickettsiosis and ehrlichiosis heavily impact other parts of the country, namely the mid-south. Understanding tick and pathogen distributions and prevalence traditionally requires active surveillance, which quickly becomes logistically and financially unrealistic as the geographic area of focus increases. We report on a community science effort to survey ticks across Arkansas to obtain updated data on tick distributions and prevalence of human tick-borne disease-causing pathogens in the most commonly encountered ticks. During a 20-mo period, Arkansans submitted 9,002 ticks from 71 of the 75 counties in the state. Amblyomma americanum was the most common tick species received, accounting for 76% of total tick submissions. Nearly 6,000 samples were screened for spotted fever group Rickettsia (SFGR) and Ehrlichia, resulting in general prevalence rates of 37.4 and 5.1%, respectively. In addition, 145 ticks (2.5%) were infected with both SFGR and Ehrlichia. Arkansas Department of Health reported 2,281 spotted fever and 380 ehrlichiosis cases during the same period as our tick collections. Since known SFGR vectors Dermacentor variabilis and Amblyomma maculatum were not the most common ticks submitted, nor did they have the highest prevalence rates of SFGR, it appears that other tick species play the primary role in infecting humans with SFGR. Our investigation demonstrated the utility of community science to efficiently and economically survey ticks and identify vector-borne disease risk in Arkansas.

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Association of the invasive Haemaphysalis longicornis tick with vertebrate hosts, other native tick vectors, and tick-borne pathogens in New York City

10.1101/2020.07.01.182626 ◽

2020 ◽

Author(s):

Danielle M. Tufts ◽

Laura B. Goodman ◽

Meghan C. Benedict ◽

April D. Davis ◽

Meredith C. VanAcker ◽

...

Keyword(s):

United States ◽

New York ◽

Vector Potential ◽

The United States ◽

Dermacentor Variabilis ◽

Amblyomma Americanum ◽

Invasive Pest ◽

Haemaphysalis Longicornis ◽

Tick Vectors ◽

Host Associations

AbstractHaemaphysalis longicornis, the Asian longhorned tick, is an invasive ixodid tick that has rapidly spread across the northeastern and southeastern regions of the United States since first reported in 2017. The emergence of H. longicornis presents a potential threat for livestock, wildlife, and human health as the host associations and vector potential of this invasive pest in the United States are poorly understood. Previous field data from the United States has shown that H. longicornis was not associated with natural populations of small mammals or birds, but they show a preference for medium sized mammals in laboratory experiments. Therefore, medium and large sized mammals were sampled on Staten Island, New York to determine H. longicornis host associations and vector potential for a range of human and veterinary pathogens. A total of 97 hosts were sampled and five species of tick (Amblyomma americanum, Dermacentor variabilis, H. longicornis, Ixodes scapularis, Ixodes cookei) were found feeding concurrently on these hosts. Haemaphysalis longicornis was found in the highest proportions compared to other native tick species on raccoons (55.4%), Virginia opossums (28.9%), and white-tailed deer (11.5%). Tissue, blood, and engorged larvae were tested for 17 different pathogens using a nanoscale PCR platform. Infection with five pathogens (Borrelia burgdorferi, Anaplasma phagocytophilum, Rickettsia spp., Mycoplasma haemocanis, and Bartonella spp.) was detected in host samples, but no pathogens were found in any larval samples. These results suggest that although large and medium sized mammals feed large numbers of H. longicornis ticks in the environment there is presently a low potential for H. longicornis to acquire pathogens from these wildlife hosts.HighlightsH. longicornis were sampled from seven genera of large and medium-sized mammalsRaccoons, opossums, and white-tailed deer fed a large proportion of H. longicornisH. longicornis did not acquire pathogens through co-feeding with native tick vectorsHost species were infected with a range of pathogens of human and veterinary concernHost-derived H. longicornis engorged larvae were not infected with any pathogens

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Modeling the Distribution of Medically Important Tick Species in Florida

Insects ◽

10.3390/insects10070190 ◽

2019 ◽

Vol 10 (7) ◽

pp. 190 ◽

Cited By ~ 8

Author(s):

William H. Kessler ◽

Claudia Ganser ◽

Gregory E. Glass

Keyword(s):

Habitat Suitability ◽

Vegetation Index ◽

Normalized Difference Vegetation Index ◽

Ixodes Scapularis ◽

Dermacentor Variabilis ◽

Amblyomma Americanum ◽

Suitable Habitat ◽

Public Health Importance ◽

Raising Awareness ◽

Great Public Health

The lone star (Amblyomma americanum), black-legged (Ixodes scapularis) and American dog ticks (Dermacentor variabilis) are species of great public health importance as they are competent vectors of several notable pathogens. While the regional distributions of these species are well characterized, more localized distribution estimates are sparse. We used records of field collected ticks and an ensemble modeling approach to predict habitat suitability for each of these species in Florida. Environmental variables capturing climatic extremes were common contributors to habitat suitability. Most frequently, annual precipitation (Bio12), mean temperature of the driest quarter (Bio9), minimum temperature of the coldest month (Bio6), and mean Normalized Difference Vegetation Index (NDVI) were included in the final models for each species. Agreement between the modeling algorithms used in this study was high and indicated the distribution of suitable habitat for all three species was reduced at lower latitudes. These findings are important for raising awareness of the potential for tick-borne pathogens in Florida.

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Role of the male claw sensilla in perception of female mounting sex pheromone in Dermacentor variabilis, Dermacentor andersoni and Amblyomma americanum

Experimental and Applied Acarology ◽

10.1007/bf00058504 ◽

1993 ◽

Vol 17 (9) ◽

pp. 631-653 ◽

Cited By ~ 9

Author(s):

James S. Phillips ◽

Daniel E. Sonenshine

Keyword(s):

Sex Pheromone ◽

Dermacentor Variabilis ◽

Amblyomma Americanum ◽

Dermacentor Andersoni ◽

Mounting Sex Pheromone

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Wildfire and exotic grass invasion alter plant productivity in response to climate variability in the Mojave Desert

Landscape Ecology ◽

10.1007/s10980-016-0466-7 ◽

2016 ◽

Vol 32 (3) ◽

pp. 635-646 ◽

Cited By ~ 14

Author(s):

Kevin J. Horn ◽

Samuel B. St. Clair

Keyword(s):

Climate Variability ◽

Mojave Desert ◽

Plant Productivity ◽

Exotic Grass ◽

Grass Invasion

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Low Abundance of Three Tick Species in the Piedmont of North Carolina

Journal of Medical Entomology ◽

10.1093/jme/tjaa171 ◽

2020 ◽

Author(s):

Madeline P Seagle ◽

Maximilian R Vierling ◽

Ryan J Almeida ◽

D Jacob Clary ◽

Will Hidell ◽

...

Keyword(s):

North Carolina ◽

Ixodes Scapularis ◽

Dermacentor Variabilis ◽

Amblyomma Americanum ◽

Host Factors ◽

Southeast United States ◽

The North ◽

Mecklenburg County ◽

North Carolina Piedmont ◽

Multiple Species

Abstract Multiple species of ticks, including Ixodes scapularis (Say, Ixodida:Ixodidae), Amblyomma americanum (L., Ixodida:Ixodidae), and Dermacentor variabilis (Say, Ixodida:Ixodidae), occur in high and increasing abundance in both the northeast and southeast United States. North Carolina is at the nexus of spread of these species, with high occurrence and abundance of I. scapularis to the north and A. americanum to the south. Despite this, there are few records of these species in the Piedmont of North Carolina, including the greater Charlotte metropolitan area. Here, we update the known occurrence and abundance of these species in the North Carolina Piedmont. We surveyed for ticks using cloth drags, CO2 traps, and leaf litter samples at a total of 79 sites within five locations: Mecklenburg County, South Mountains State Park, Stone Mountain State Park, Duke Forest, and Morrow Mountain State Park, all in North Carolina, during the late spring, summer, and fall seasons of 2019. From these surveys, we had only 20 tick captures, illuminating the surprisingly low abundance of ticks in this region of North Carolina. Our results indicate the possibility of underlying habitat and host factors limiting tick distribution and abundance in the North Carolina Piedmont.

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A Francisella tularensis Chitinase Contributes to Bacterial Persistence and Replication in Two Major U.S. Tick Vectors

Pathogens ◽

10.3390/pathogens9121037 ◽

2020 ◽

Vol 9 (12) ◽

pp. 1037

Author(s):

Brenden G. Tully ◽

Jason F. Huntley

Keyword(s):

Francisella Tularensis ◽

Alternative Energy ◽

Vector Competence ◽

Chitinase Activity ◽

Dermacentor Variabilis ◽

Amblyomma Americanum ◽

Haemaphysalis Longicornis ◽

Order Of Magnitude ◽

Transmission Studies

Nearly 100 years after the first report of tick-borne tularemia, questions remain about the tick vector(s) that pose the greatest risk for transmitting Francisella tularensis (Ft), the causative agent of tularemia. Additionally, few studies have identified genes/proteins required for Ft to infect, persist, and replicate in ticks. To answer questions about vector competence and Ft transmission by ticks, we infected Dermacentor variabilis (Dv),Amblyomma americanum (Aa), and Haemaphysalis longicornis (Hl; invasive species from Asia) ticks with Ft, finding that although Aa ticks initially become infected with 1 order of magnitude higher Ft, Ft replicated more robustly in Dv ticks, and did not persist in Hl ticks. In transmission studies, both Dv and Aa ticks efficiently transmitted Ft to naïve mice, causing disease in 57% and 46% of mice, respectively. Of four putative Ft chitinases, FTL1793 is the most conserved among Francisella sp. We generated a ΔFTL1793 mutant and found that ΔFTL1793 was deficient for infection, persistence, and replication in ticks. Recombinant FTL1793 exhibited chitinase activity in vitro, suggesting that FTL1793 may provide an alternative energy source for Ft in ticks. Taken together, Dv ticks appear to pose a greater risk for harboring and transmitting tularemia and FTL1793 plays a major role in promoting tick infections by Ft.

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