scholarly journals Likely Geographic Distributional Shifts among Medically Important Tick Species and Tick-Associated Diseases under Climate Change in North America: A Review

Insects ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 225
Author(s):  
Abdelghafar Alkishe ◽  
Ram K. Raghavan ◽  
Andrew T. Peterson
Keyword(s):  
Climate Change ◽  
North America ◽  
Tick Species ◽  
Disease Incidence ◽  
Spotted Fever ◽  
Dermacentor Variabilis ◽  
Amblyomma Americanum ◽  
Ecological Niche Models ◽  
Rocky Mountain Spotted Fever ◽  
Associated Diseases

Ticks rank high among arthropod vectors in terms of numbers of infectious agents that they transmit to humans, including Lyme disease, Rocky Mountain spotted fever, Colorado tick fever, human monocytic ehrlichiosis, tularemia, and human granulocytic anaplasmosis. Increasing temperature is suspected to affect tick biting rates and pathogen developmental rates, thereby potentially increasing risk for disease incidence. Tick distributions respond to climate change, but how their geographic ranges will shift in future decades and how those shifts may translate into changes in disease incidence remain unclear. In this study, we have assembled correlative ecological niche models for eight tick species of medical or veterinary importance in North America (Ixodes scapularis, I. pacificus, I. cookei, Dermacentor variabilis, D. andersoni, Amblyomma americanum, A. maculatum, and Rhipicephalus sanguineus), assessing the distributional potential of each under both present and future climatic conditions. Our goal was to assess whether and how species’ distributions will likely shift in coming decades in response to climate change. We interpret these patterns in terms of likely implications for tick-associated diseases in North America.

Collaborating With Community Scientists Across Arkansas to Update Tick Distributions and Pathogen Prevalence of Spotted Fever Group Rickettsia and Ehrlichia

2021 ◽  
Author(s):  
Ashley P G Dowling ◽  
Sean G Young ◽  
Kelly Loftin
Keyword(s):  
Tick Species ◽  
Spotted Fever ◽  
Dermacentor Variabilis ◽  
Amblyomma Americanum ◽  
Spotted Fever Group ◽  
Primary Role ◽  
Prevalence Rates ◽  
Spotted Fever Group Rickettsia ◽  
Community Science ◽  
Tick Distributions

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.

scholarly journals Molecular Detection of Spotted Fever Group Rickettsiae (Rickettsiales: Rickettsiaceae) in Dermacentor variabilis (Acari: Ixodidae) Collected Along the Platte River in South Central Nebraska

2019 ◽  
Vol 57 (2) ◽  
pp. 519-523
Author(s):  
Brandon E Luedtke ◽  
Julie J Shaffer ◽  
Estrella Monrroy ◽  
Corey W Willicott ◽  
Travis J Bourret
Keyword(s):  
Spotted Fever ◽  
Rocky Mountain ◽  
Dermacentor Variabilis ◽  
Amblyomma Americanum ◽  
Spotted Fever Group ◽  
Rocky Mountain Spotted Fever ◽  
Rickettsia Species ◽  
Platte River ◽  
Rickettsia Rickettsii ◽  
South Central

Abstract Dermacentor variabilis is the predominant tick species in Nebraska and is presumed to be the primary vector of Rickettsia rickettsii associated with cases of Rocky Mountain spotted fever (RMSF). Interestingly, RMSF cases in Nebraska have increased on a year-to-year basis, yet the prevalence of R. rickettsii in D. variabilis ticks has not been established for Nebraska. Here we sought to set a baseline for the prevalence of R. rickettsii and other spotted fever group (SFG) rickettsiae harbored by D. variabilis ticks. Over a 3-yr period, D. variabilis were collected along the Platte River in south central Nebraska. Individual tick DNA was analyzed using endpoint PCR to identify ticks carrying SFG rickettsiae. In total, 927 D. variabilis were analyzed by PCR and 38 (4.1%) ticks tested positive for SFG rickettsiae. Presumptive positives were sequenced to identify the Rickettsia species, of which 29 (76%) were R. montanensis, 5 (13%) were R. amblyommatis, 4 (11%) were R. bellii, and R. rickettsii was not detected. These data indicate that R. rickettsii is likely at a low prevalence in south central Nebraska and spillover of R. amblyommatis into D. variabilis is likely occurring due to the invasive lone star tick (Amblyomma americanum). In addition, our data suggest that R. montanensis and R. amblyommatis could be associated with the increase in SFG rickettsiae infections in Nebraska. This information will be of value to clinicians and the general public for evaluating diagnosis of disease- and risk-associated environmental exposure, respectively.

scholarly journals Dermacentor variabilis is the Predominant Dermacentor spp. (Acari: Ixodidae) Feeding on Dogs and Cats Throughout the United States

2021 ◽  
Author(s):  
Kathryn T Duncan ◽  
Meriam N Saleh ◽  
Kellee D Sundstrom ◽  
Susan E Little
Keyword(s):  
United States ◽  
Spotted Fever ◽  
Rocky Mountain ◽  
The United States ◽  
Dermacentor Variabilis ◽  
Western United States ◽  
Its2 Region ◽  
Rrna Gene ◽  
Rocky Mountain Spotted Fever ◽  
Dermacentor Albipictus

Abstract Throughout North America, Dermacentor spp. ticks are often found feeding on animals and humans, and are known to transmit pathogens, including the Rocky Mountain spotted fever agent. To better define the identity and distribution of Dermacentor spp. removed from dogs and cats in the United States, ticks submitted from 1,457 dogs (n = 2,924 ticks) and 137 cats (n = 209 ticks) from veterinary practices in 44/50 states from February 2018-January 2020 were identified morphologically (n = 3,133); the identity of ticks from regions where Dermacentor andersoni (Stiles) have been reported, and a subset of ticks from other regions, were confirmed molecularly through amplification and sequencing of the ITS2 region and a 16S rRNA gene fragment. Of the ticks submitted, 99.3% (3,112/3,133) were Dermacentor variabilis (Say), 0.4% (12/3,133) were D. andersoni, and 0.3% (9/3,133) were Dermacentor albipictus (Packard). While translocation of pets prior to tick removal cannot be discounted, the majority (106/122; 87%) of Dermacentor spp. ticks removed from dogs and cats in six Rocky Mountain states (Montana, Idaho, Wyoming, Nevada, Utah, and Colorado) were D. variabilis, suggesting this species may be more widespread in the western United States than is currently recognized, or that D. andersoni, if still common in the region, preferentially feeds on hosts other than dogs and cats. Together, these data support the interpretation that D. variabilis is the predominant Dermacentor species found on pets throughout the United States, a finding that may reflect recent shifts in tick distribution.

Ticks and tick-borne pathogens in China.

2021 ◽  
pp. 492-499
Author(s):  
Hao Li ◽  
Li-Qun Fang ◽  
Wei Liu
Keyword(s):  
Climate Change ◽  
Global Warming ◽  
Expert Opinion ◽  
Tick Species ◽  
Spotted Fever ◽  
Spotted Fever Group ◽  
Human Beings ◽  
Potential Influence ◽  
Spotted Fever Group Rickettsiae ◽  
Tick Vectors

Abstract This expert opinion provides an overview of the type and distribution of tick species and emerging tick-borne pathogens in tick vectors and human beings (such as Anaplasma, Babesia, spotted fever group rickettsiae, Borrelia and viruses) in China and considers the potential influence of global warming and climate change.

Rickettsial Diseases

2017 ◽  
Author(s):  
Lisa Sun ◽  
Michael V. Johnston
Keyword(s):  
Endothelial Cells ◽  
Q Fever ◽  
Spotted Fever ◽  
The United States ◽  
Dermacentor Variabilis ◽  
Farm Animals ◽  
Spotted Fever Group ◽  
Rocky Mountain Spotted Fever ◽  
The World ◽  
The Brain

Tick-borne rickettsioses are emerging as more important health problems throughout the world. The spotted fever group including Rickettsia rickettsia can cause encephalopathy, meningitis and brain damage by selectively targeting capillary endothelial cells in the brain, and stimulating inflammation, capillary leakage, hemorrhage, and intravascular coagulation. Rickettsia are are arthropod-borne gram-negative coccobacilli bacteria and are obligate intracellular organisms that do not survive in artificial medium. In North and South America, the most common rickettsial disorder is rocky mountain spotted fever (RMSF) transmitted by the dog tick Dermacentor variabilis or the wood tick Dermacentor andersoni. A characteristic “starry sky” pattern can be seen on MRI imaging of the brain in some patients with RMSF encephalopathy and is thought to reflect the organisms targeting of brain endothelial cells in capillaries the white matter. Early treatment with doxycycline is curative and reverses signs of encephalopathy if given within a few day of onset, but delayed treatment can be associated with permanent neurological disability. The typhus group of rickettsia bacteria include R. prowazekii, which causes epidemic typhus and R. typhi, which causes murine typhus (endemic) typhus in tropical and subtropical parts of the world. Flying squirrels and humans carry R prowazekii and rats are carry R. typhi. Q fever caused by the rickettsia organism Coxiella burnetti is transmitted from farm animals including sheep and is seen throughout the world including the United States.

Potential impacts of climate change on medically important tick species in North America.

2021 ◽  
pp. 145-151
Author(s):  
Geoffrey Lynn ◽  
Sukanya Narasimhan ◽  
Erol Fikrig
Keyword(s):  
Climate Change ◽  
Land Use ◽  
North America ◽  
Tick Species ◽  
Anthropogenic Disturbances ◽  
Impacts Of Climate Change

Abstract This chapter focuses on how climate change, together with land use and anthropogenic disturbances, can impact the biology and ecology of medically important ticks as well as the prevalence of tick-borne diseases in North America.

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