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

   https://doi.org/10.1093/jme/tjab007  

   Duncan, Kathryn T; Saleh, Meriam N; Sundstrom, Kellee D; Little, Susan E (February 2021, Journal of Medical Entomology)

   Hamer, Sarah (Ed.)

   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. 

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2. Local community composition drives avian Borrelia burgdorferi infection and tick infestation

   https://doi.org/10.3390/vetsci9020055  

   Lilly, M.; Amaya-Mejia, W.; Pavan, L.; Peng, C.; Crews, A.; Tran, N.; Sehgal, R.; Swei, A. (January 2022, Veterinary sciences)

   Globally, zoonotic vector-borne diseases are on the rise and understanding their complex transmission cycles is pertinent to mitigating disease risk. In North America, Lyme disease is the most commonly reported vector-borne disease and is caused by transmission of Borrelia burgdorferi sensu lato (s.l.) from Ixodes spp. ticks to a diverse group of vertebrate hosts. Small mammal reservoir hosts are primarily responsible for maintenance of B. burgdorferi s.l. across the United States. Never- theless, birds can also be parasitized by ticks and are capable of infection with B. burgdorferi s.l. but their role in B. burgdorferi s.l. transmission dynamics is understudied. Birds could be important in both the maintenance and spread of B. burgdorferi s.l. and ticks because of their high mobility and shared habitat with important mammalian reservoir hosts. This study aims to better understand the role of avian hosts in tick-borne zoonotic disease transmission cycles in the western United States. We surveyed birds, mammals, and ticks at nine sites in northern California for B. burgdorferi s.l. infection and collected data on other metrics of host community composition such as abundance and diversity of birds, small mammals, lizards, predators, and ticks. We found 22.8% of birds infected with B. burgdorferi s.l. and that the likelihood of avian B. burgdorferi s.l. infection was significantly associated with local host community composition and pathogen prevalence in California. Addition- ally, we found an average tick burden of 0.22 ticks per bird across all species. Predator and lizard abundances were significant predictors of avian tick infestation. These results indicate that birds are relevant hosts in the local B. burgdorferi s.l. transmission cycle in the western United States and quantifying their role in the spread and maintenance of Lyme disease requires further research. 

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3. Early evidence of establishment of the tropical bedbug ( Cimex hemipterus ) in Central Europe

   https://doi.org/10.1111/mve.12522  

   Balvín, O.; Sasínková, M.; Martinů, J.; Nazarizadeh, M.; Bubová, T.; Booth, W.; Vargo, E. L.; Štefka, J. (May 2021, Medical and Veterinary Entomology)

   Abstract In recent decades, the world has witnessed a remarkable resurgence of bedbugs (Hemiptera: Cimicidae). Although populations of the common bedbug,Cimex lectulariusL., expanded in temperate regions of its original distribution, the tropical bedbug,C. hemipterus(F.), increased its abundance in warmer regions, where it also had been historically distributed. However,C. hemipterushas recently been observed to be expanding to other areas, e.g. North Australia, Middle East, the United States and Russia. In other parts of Europe, few sporadic and ephemeral introductions ofC. hemipteruswere recorded until recently. We conducted an extensive sampling of European bedbug populations starting in 2002 and found thatC. hemipterushas recently become locally established. Among 566 examined infestations, nearly all of which involvedC. lectularius,C. hemipterusoccurred in six infestations collected since 2019. In at least three cases, the social background of inhabitants of the infested properties indicated that tropical bedbugs likely spread within local communities. Using cytochrome oxidase subunit I, we linked five of the infestations to the most common haplotype found globally, and one to an African haplotype. In all infestations, we observed twokdr‐associated mutations in the sodium channel gene, which are also commonly found across the world. 

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4. Modeling of Control Efforts against Rhipicephalus sanguineus, the Vector of Rocky Mountain Spotted Fever in Sonora Mexico

   https://doi.org/10.3390/insects13030263  

   Alvarez-Hernandez, Gerardo; Trejo, Alejandro Villegas; Ratti, Vardayani; Teglas, Michael; Wallace, Dorothy I. (March 2022, Insects)

   Rocky Mountain spotted fever (RMSF) is a significant health problem in Sonora, Mexico. The tick vector, Rhipicephalus sanguineus, feeds almost exclusively on domestic dogs that, in this region, also serve as the reservoir for the tick-borne pathogen, Rickettsia rickettsii. A process-based mathematical model of the life cycle of R. sanguineus was developed to predict combinations of insecticidal dog collars and long-lasting insecticidal wall treatments resulting in suppression of indoor tick populations. Because of a high burden of RMSF in a rural community near the Sonora state capital of Hermosillo, a test area was treated with a combination of insecticidal dog collars and long-lasting insecticidal wall treatments from March 2018 to April 2019, with subsequent reduction in RMSF cases and deaths. An estimated 80% of the dogs in the area had collars applied and 15% of the houses were treated. Data on tick abundance on walls and dogs, collected during this intervention, were used to parameterize the model. Model results show a variety of treatment combinations likely to be as successful as the one carried out in the test community. 

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5. Long-term soil fungal community recovery after fire is impacted by climate change

   https://doi.org/10.3398/064.082.0303  

   McGee, S.; Tidwell, A.; Riggs, E.; Veltkamp, H.; Zahn, G. (August 2022, Western North American naturalist)

   Though much is known about fungal importance to forest health, there is very little information about factors that impact recovery times of soil fungal communities after a fire. Soil samples were taken from burn sites within one ecotype of temperate coniferous forest in Utah over a 20-year chronosequence. Sites were selected from available historic burns and were similar in plant community structure, elevation, slope, and aspect. Fungal DNA from these samples was compared to soil from paired unburned sites nearby to measure community similarity and estimate soil fungal recovery rates. Differences between paired burned and unburned sites remained fairly stable over a decadal timescale overall, but fungal community structure was found to recover more quickly in areas with a higher average annual temperature. A significant positive correlation in community recovery was seen in areas with a difference of as little as 2 °C per year. The only other environmental variable that significantly interacted with time since burn was annual mean precipitation. As global temperatures increase, alpine fires are increasing as well, but these results suggest that fungal community recovery time will be shortened under new climate scenarios. 

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