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1.
J Med Entomol ; 61(3): 781-790, 2024 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-38408183

RESUMO

The Pacific Coast tick (Dermacentor occidentalis Marx, 1892) is a frequently encountered and commonly reported human-biting tick species that has been recorded from most of California and parts of southwestern Oregon, southcentral Washington, and northwestern Mexico. Although previous investigators have surveyed populations of D. occidentalis for the presence of Rickettsia species across several regions of California, populations of this tick have not been surveyed heretofore for rickettsiae from Baja California, Oregon, or Washington. We evaluated 1,367 host-seeking, D. occidentalis adults collected from 2015 to 2022 by flagging vegetation at multiple sites in Baja California, Mexico, and Oregon and Washington, United States, using genus- and species-specific assays for spotted fever group rickettsiae. DNA of Rickettsia 364D, R. bellii, and R. tillamookensis was not detected in specimens from these regions. DNA of R. rhipicephali was detected in D. occidentalis specimens obtained from Ensenada Municipality in Baja California and southwestern Oregon, but not from Washington. All ompA sequences of R. rhipichephali that were amplified from individual ticks in southwestern Oregon were represented by a single genotype. DNA of the Ixodes pacificus rickettsial endosymbiont was amplified from specimens collected in southwestern Oregon and Klickitat County, Washington; to the best of our knowledge, this Rickettsia species has never been identified in D. occidentalis. Collectively, these data are consistent with a relatively recent introduction of Pacific Coast ticks in the northernmost extension of its recognized range.


Assuntos
Dermacentor , Rickettsia , Animais , Rickettsia/isolamento & purificação , Rickettsia/genética , Dermacentor/microbiologia , Washington , Oregon , Feminino , México , Masculino
2.
Ticks Tick Borne Dis ; 13(6): 102041, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36257186

RESUMO

Anaplasmosis is increasingly common in the United States, with cases being reported over an expanding geographic area. To monitor for changes in risk of human infection, the U.S. Centers for Disease Control and Prevention monitors the distribution and abundance of host-seeking vector ticks (Ixodes scapularis and Ixodes pacificus) and their infection with Anaplasma phagocytophilum. While several variants of A. phagocytophilum circulate in I. scapularis, only the human-active variant (Ap-ha) appears to be pathogenic in humans. Failure to differentiate between human and non-human variants may artificially inflate estimates of the risk of human infection. Efforts to differentiate the Ap-ha variant from the deer variant (Ap-V1) in ticks typically rely on traditional PCR assays coupled with sequencing of PCR products. However, laboratories are increasingly turning to Next Generation Sequencing (NGS) to increase testing efficiency, retain high sensitivity, and increase specificity compared with traditional PCR assays. We describe a new NGS assay with novel targets that accurately segregate the Ap-ha variant from other non-human variants and further identify unique clades within the human and non-human variants. Recognizing that not all investigators have access to NGS technology, we also developed a PCR assay based on one of the novel targets so that variants can be visualized using agarose gel electrophoresis without the need for subsequent sequencing. Such an assay may be used to improve estimates of human risk of developing anaplasmosis in North America.

3.
Zoonoses Public Health ; 69(2): 143-148, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34958171

RESUMO

The Asian longhorned tick, Haemaphysalis longicornis, an invasive species associated with human pathogens, has spread rapidly across the eastern USA. Questing H. longicornis ticks recovered from active surveillance conducted from 1 May to 6 September, 2019 throughout Pennsylvania were tested for rickettsial pathogens. Of 265 ticks tested by PCR for pathogens, 4 (1.5%) were positive for Anaplasma phagocytophilum. Sequence analysis of the 16S rRNA gene confirmed two positives as A. phagocytophilum-human agent variant. This is the first reported detection of A. phagocytophilum-human pathogenic strain DNA in exotic H. longicornis collected in the USA.


Assuntos
Anaplasma phagocytophilum , Ixodidae , Carrapatos , Anaplasma phagocytophilum/genética , Animais , Humanos , Pennsylvania/epidemiologia , RNA Ribossômico 16S/genética
4.
J Am Mosq Control Assoc ; 37(4): 296-297, 2021 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-34817609

RESUMO

The Asian longhorned tick, Haemaphysalis longicornis, is an invasive species, originally from eastern Asia, and was first reported in the USA in New Jersey. It is now reported in several eastern states. In 2018, researchers reported H. longicornis in northwest Arkansas (Benton County). This tick species is a proven vector of livestock and human diseases, which prompted the current survey of ticks in southwest Missouri. A tick drag in Greene County, Missouri, produced 2 H. longicornis nymphs on June 9, 2021. This is the first report of this species for both the state and county.


Assuntos
Ixodidae , Carrapatos , Animais , Humanos , Espécies Introduzidas , Missouri , Ninfa
5.
J Med Entomol ; 58(3): 1459-1462, 2021 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-33458776

RESUMO

We identified an established population of the Gulf Coast tick (Amblyomma maculatum Koch) infected with Rickettsia parkeri in Connecticut, representing the northernmost range limit of this medically relevant tick species. Our finding highlights the importance of tick surveillance and public health challenges posed by geographic expansion of tick vectors and their pathogens.


Assuntos
Amblyomma/microbiologia , Vetores Aracnídeos/microbiologia , Rickettsia/isolamento & purificação , Amblyomma/crescimento & desenvolvimento , Distribuição Animal , Animais , Vetores Aracnídeos/crescimento & desenvolvimento , Connecticut , Feminino , Larva/crescimento & desenvolvimento , Larva/microbiologia , Masculino , Ninfa/crescimento & desenvolvimento , Ninfa/microbiologia
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