scholarly journals VECTOR COMPETENCE IN LYME DISEASE : STUDIES ON IXODES SCAPULARIS, DERMACENTOR VARIABILIS, AND AMBLYOMMA AMERICANUM

Author(s):  
◽  
Min-Tsung Yeh

1989 ◽  
Vol 24 (4) ◽  
pp. 594-602 ◽  
Author(s):  
Jay F. Levine ◽  
Charles S. Apperson ◽  
William L. Nicholson

Ticks were collected at 6 sites in North Carolina identified as the location of tick contact by Lyme disease patients, and at 6 sites located in counties where cases had been diagnosed. Specimens were screened for evidence of spirochete infection; fewer than 1% of the specimens collected harbored spirochetes. Indirect fluorescence antibody testing, with a species-specific monoclonal antibody, confirmed that one Ixodes scapularis Say collected at the residence of a Lyme disease patient was infected with Borrelia burgdorferi Johnson, Hyde, Schmid, and Brenner. Two specimens (Amblyomma americanum (L.) and I. scapularis) screened by a direct fluorescence antibody test with polyclonal antisera were infected with Borrelia. Spirochetes other than B. burgdorferi were found in A. americanum. No spirochetes were observed in Dermacentor variabilis (Say) or I. brunneus (Koch).



2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Rohit Sharma ◽  
Duncan W. Cozens ◽  
Philip M. Armstrong ◽  
Douglas E. Brackney

Abstract Background Powassan virus (POWV; genus Flavivirus) is the sole North American member of the tick-borne encephalitis sero-complex and an increasing public health threat in the USA. Maintained in nature by Ixodes spp. ticks, POWV has also been isolated from species of other hard tick genera, yet it is unclear if these species can serve as vectors. Dermacentor variabilis and Amblyomma americanum share geographic and ecologic overlap with Ixodes spp. ticks and POWV transmission foci, raising the possibility that POWV could become established in these tick species and leading to range expansion and increased human risk. Therefore, we assessed the competency of Ixodes scapularis, D. variabilis and A. americanum for POWV lineage II (POWV II). Methods Larvae from all three species were co-infested on POWV-infected Balb/c mice. The engorged larvae were allowed to molt to nymphs and screened for the presence of POWV II RNA by reverse transcription-qPCR. Eight infected nymphs from each species were allowed to individually feed on a naïve mouse. Mice were screened for the presence of POWV II RNA to determine infection status. Results The results demonstrated that larvae from all three tick species were able to efficiently acquire POWV II via feeding on viremic mice, maintain infection through molting and successively transmit POWV to naïve mice at the nymphal stage at comparable rates across all three species. Conclusions Our findings reveal that non-Ixodes tick species can serve as competent vectors for POWV and highlight the potential role of these species in the ecology and epidemiology of POWV. Future studies examining the possible implications of these findings on POWV epidemiology and the adaptability of POWV in these new vectors are warranted. Graphical abstract



Insects ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 190 ◽  
Author(s):  
William H. Kessler ◽  
Claudia Ganser ◽  
Gregory E. Glass

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.



Author(s):  
Madeline P Seagle ◽  
Maximilian R Vierling ◽  
Ryan J Almeida ◽  
D Jacob Clary ◽  
Will Hidell ◽  
...  

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.



Pathogens ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1037
Author(s):  
Brenden G. Tully ◽  
Jason F. Huntley

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.



2004 ◽  
Vol 39 (3) ◽  
pp. 426-432 ◽  
Author(s):  
Alan B. Wells ◽  
Lance A. Durden ◽  
John H. Smoyer

Ticks (Acari: Ixodidae) were collected from family-owned domestic dogs, Canis familiaris L., in Bulloch Co., GA, from 1996 to 2003 and from dogs maintained in a shelter in Emanuel Co., GA, in 2002 and 2003. A total of 2,466 ticks representing 9 species was recovered. The most frequently recovered species from family-owned dogs were the blacklegged tick, Ixodes scapularis Say (54.6% of all ticks from this group of dogs), and American dog tick, Dermacentor variabilis (Say) (27.7%). Collections from shelter-maintained dogs were dominated by the brown dog tick, Rhipicephalus sanguineus (Latreille) (73.6%). Except for 39 nymphs of the lone star tick, Amblyomma americanum (L.), 12 nymphs of R. sanguineus, 7 nymphs of the Gulf Coast tick, Amblyomma maculatum Koch, 1 nymph of D. variabilis and 72 larvae of the gopher tortoise tick, Amblyomma tuberculatum Marx, only adult ticks were present. Seasonally, I. scapularis adults were recorded from October through May and were most common in the fall; whereas, A. americanum, A. maculatum, A. tuberculatum, D. variabilis, and Ixodes affinis Neumann were all found only during the spring, summer and/or early fall. Two species of ticks collected during this study, A. tuberculatum and I. affinis, have Coastal Plain distributions in the southern U.S. and would only be expected to parasitize dogs within this region.



mSphere ◽  
2018 ◽  
Vol 3 (2) ◽  
Author(s):  
Rafal Tokarz ◽  
Stephen Sameroff ◽  
Teresa Tagliafierro ◽  
Komal Jain ◽  
Simon H. Williams ◽  
...  

ABSTRACT Ticks carry a wide range of known human and animal pathogens and are postulated to carry others with the potential to cause disease. Here we report a discovery effort wherein unbiased high-throughput sequencing was used to characterize the virome of 2,021 ticks, including Ixodes scapularis ( n = 1,138), Amblyomma americanum ( n = 720), and Dermacentor variabilis ( n = 163), collected in New York, Connecticut, and Virginia in 2015 and 2016. We identified 33 viruses, including 24 putative novel viral species. The most frequently detected viruses were phylogenetically related to members of the Bunyaviridae and Rhabdoviridae families, as well as the recently proposed Chuviridae . Our work expands our understanding of tick viromes and underscores the high viral diversity that is present in ticks. IMPORTANCE The incidence of tick-borne disease is increasing, driven by rapid geographical expansion of ticks and the discovery of new tick-associated pathogens. The examination of the tick microbiome is essential in order to understand the relationship between microbes and their tick hosts and to facilitate the identification of new tick-borne pathogens. Genomic analyses using unbiased high-throughput sequencing platforms have proven valuable for investigations of tick bacterial diversity, but the examination of tick viromes has historically not been well explored. By performing a comprehensive virome analysis of the three primary tick species associated with human disease in the United States, we gained substantial insight into tick virome diversity and can begin to assess a potential role of these viruses in the tick life cycle.



Sign in / Sign up

Export Citation Format

Share Document