scholarly journals Modelling spatial concordance between Rocky Mountain spotted fever disease incidence and habitat probability of its vector Dermacentor variabilis (American dog tick)

2012 ◽  
Vol 7 (1) ◽  
pp. 91 ◽  
Author(s):  
Samuel F. Atkinson ◽  
Sahotra Sarkar ◽  
Aldo Aviña ◽  
Jim A. Schuermann ◽  
Phillip Williamson
Keyword(s):  
Disease Incidence ◽  
Spotted Fever ◽  
Rocky Mountain ◽  
Dermacentor Variabilis ◽  
Rocky Mountain Spotted Fever ◽  
American Dog Tick ◽  
Spatial Concordance ◽  
Dog Tick

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.

scholarly journals Exploring the niche of Rickettsia montanensis (Rickettsiales: Rickettsiaceae) infection of the American dog tick (Acari: Ixodidae), using multiple species distribution model approaches.

2020 ◽  
Author(s):  
Catherine Lippi ◽  
Holly D Gaff ◽  
Alexis L White ◽  
Heidi K St John ◽  
Allen L Richards ◽  
...  
Keyword(s):  
Species Distribution ◽  
Species Distribution Model ◽  
Health Planning ◽  
Spotted Fever ◽  
Dermacentor Variabilis ◽  
Distribution Model ◽  
Spotted Fever Group ◽  
Modeling Framework ◽  
American Dog Tick ◽  
Dog Tick

The American dog tick, Dermacentor variabilis (Say), is a vector for several human disease causing pathogens such as tularemia, Rocky Mountain spotted fever, and the understudied spotted fever group rickettsiae (SFGR) infection caused by Rickettsia montanensis. It is important for public health planning and intervention to understand the distribution of this tick and pathogen encounter risk. Risk is often described in terms of vector distribution, but greatest risk may be concentrated where more vectors are positive for a given pathogen. When assessing species distributions, the choice of modeling framework and spatial layers used to make predictions are important. We first updated the modeled distribution of D. variabilis and R. montanensis using MaxEnt, refining bioclimatic data inputs, and including soils variables. We then compared geospatial predictions from five species distribution modeling (SDM) frameworks. In contrast to previous work, we additionally assessed whether the R. montanensis positive D. variabilis distribution is nested within a larger overall D. variabilis distribution, representing a fitness cost hypothesis. We found that 1) adding soils layers improved the accuracy of the MaxEnt model; 2) the predicted "infected niche" was smaller than the overall predicted niche across all models; and 3) each model predicted different sizes of suitable niche, at different levels of probability. Importantly, the models were not directly comparable in output style, which could create confusion in interpretation when developing planning tools. The random forest (RF) model had the best measured validity and fit, suggesting it may be most appropriate to these data.

RICKETTSIAL DISEASES OF ANIMALS TRANSMISSIBLE TO CHILDREN

PEDIATRICS ◽  
1958 ◽  
Vol 22 (2) ◽  
pp. 384-387
Author(s):  
Lauri Luoto
Keyword(s):  
Small Mammals ◽  
Q Fever ◽  
Natural Infection ◽  
Spotted Fever ◽  
Rocky Mountain ◽  
Amblyomma Americanum ◽  
Rocky Mountain Spotted Fever ◽  
Rickettsial Infections ◽  
Dog Tick ◽  
Rickettsial Diseases

BECAUSE rickettsial infections occur sporadically, pediatricians may not be as thoroughly familiar with them as they are with common diseases of children that are characterized by rash. Hence, the rickettsias are infrequently considered in the etiology of febrile exanthemas or fevers of undertermined origin. Rickettsial diseases of primary interest in this country are Rocky Mountain spotted fever, murine typhus, rickcttsialpox and Q fever. The agents causing these diseases exist as latent infections in arthropods and animals, and they are transmitted accidentally to man through well-defined channels of spread. An awareness of the epizootiology of rickettsial diseases in nature and of the means by which these agents are transmitted to man is helpful in establishing a diagnosis of a rickettsial disease. Therefore, salient features of the natural cycles of infection which may suggest a clinical diagnosis will be stressed, and characteristics of these diseases in children will be reviewed briefly. Rocky Mountain spotted fever is usually contracted during the spring or summer through the bite of an infected tick although infection also may be acquired by dermal contact with tissues of a crushed or improperly removed tick. The wood tick, Dermacentor andersoni, the dog tick, D. variabilis, and the lone-star tick, Amblyomma americanum, which are found, respectively, in the western, eastern, and southern United States are responsible for transmitting the organism to man. Natural infection with Rickettsia rickettsii in these species is maintained by transovarial passage of the agent and by the feeding of immature stages on infected small mammals. Environmental factors such as rainfall, temperature, food supply of small mammals, and prevalence of predators indirectly affect the abundance of ticks.

scholarly journals Community-Based Control of the Brown Dog Tick in a Region with High Rates of Rocky Mountain Spotted Fever, 2012–2013

PLoS ONE ◽  
2014 ◽  
Vol 9 (12) ◽  
pp. e112368 ◽  
Author(s):  
Naomi Drexler ◽  
Mark Miller ◽  
Justin Gerding ◽  
Suzanne Todd ◽  
Laura Adams ◽  
...  
Keyword(s):  
Spotted Fever ◽  
Rocky Mountain ◽  
Rocky Mountain Spotted Fever ◽  
Community Based ◽  
Brown Dog Tick ◽  
Dog Tick

Community-based prevention of epidemic Rocky Mountain spotted fever among minority populations in Sonora, Mexico, using a One Health approach

2019 ◽  
Vol 114 (4) ◽  
pp. 293-300 ◽  
Author(s):  
Gerardo Alvarez-Hernandez ◽  
Naomi Drexler ◽  
Christopher D Paddock ◽  
Jesus D Licona-Enriquez ◽  
Jesus Delgado-de la Mora ◽  
...  
Keyword(s):  
Spotted Fever ◽  
Public Health Problem ◽  
Rocky Mountain ◽  
Integrated Approach ◽  
Rocky Mountain Spotted Fever ◽  
Community Based Interventions ◽  
Community Based ◽  
Significant Public Health ◽  
Long Acting ◽  
Dog Tick

Abstract Background Rocky Mountain spotted fever (RMSF) is a significant public health problem in Sonora, Mexico, resulting in thousands of cases and hundreds of deaths. Outbreaks of RMSF are perpetuated by heavy brown dog tick infestations in and around homes. During 2009–2015, there were 61 RMSF cases and 23 deaths in a single community of Sonora (Community A). Methods An integrated intervention was carried out from March–November 2016 aimed at reducing tick populations with long-acting acaricidal collars on dogs, environmental acaricides applied to peri-domestic areas and RMSF education. Tick levels were measured by inspection of community dogs to monitor efficacy of the intervention. A similar neighborhood (Community B) was selected for comparison and received standard care (acaricide treatment and education). Results The prevalence of tick-infested dogs in Community A declined from 32.5% to 8.8% (p<0.01). No new cases of RMSF were identified in this area during the subsequent 18 mo. By comparison, the percentage of tick-infested dogs in Community B decreased from 19% to 13.4% (p=0.36) and two cases were reported, including one death. Conclusions Community-based interventions using an integrated approach to control brown dog ticks can diminish the morbidity and mortality attributable to RMSF.

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