An Exotic Hitchhiker: A Case Report of Importation into Connecticut from Africa of the Human Parasitizing Tick, Hyalomma truncatum (Acari: Ixodidae)

Introduction of the ectoparasite Rhipicephalus pulchellus (Ixodida: Ixodidae) into Connecticut with a human traveler from Tanzania, and a review of its importation records into the United States

Globalization, increased frequency of travel, and a rise in legal and illegal animal trades can introduce exotic ticks into the United States. We herein report the importation of a male Rhipicephalus pulchellus (Gerstäcker) on a human traveler returning to Connecticut from Tanzania, Africa, and review historical importation records of this species into the United States. This common tick is broadly distributed throughout East Africa, from Eritrea to Tanzania, has a wide host range on domestic animals and wildlife, and has been most frequently introduced into the United States on tick-infested wild animal hosts and animal trophies, but documentation of importation on humans has been rare. Archival records at the United States Department of Agriculture's National Veterinary Services Laboratories show R. pulchellus has been introduced into the United States at least 40 times over the last 62 yr. Rhipicephalus pulchellus has been linked to Rickettsia conorii, the agent of boutonneuse fever in humans, Crimean-Congo hemorrhagic fever orthonairovirus, and Nairobi sheep disease orthonairovirus. Given the potential for this exotic tick to introduce animal or human pathogens, proper surveillance, interception, identification, and reporting of these ticks are vital in protecting human and animal health.

Ticks and tick-borne microbes identified through passive and active surveillance in Alaska

Rapid environmental change in Alaska and other regions of the Arctic and sub-Arctic has raised concerns about increasing human exposure to ticks and the pathogens they carry. We tested a sample of ticks collected through a combination of passive and active surveillance from humans, domestic animals, and wildlife hosts in Alaska for a panel of the most common tick-borne pathogens in the contiguous United States to characterize the diversity of microbes present in this region. We tested 189 pooled tick samples collected in 2019-2020 for Borrelia spp., Anaplasma spp., Ehrlichia spp., and Babesia spp. using a multiplex PCR amplicon sequencing assay. We found established populations of Ixodes angustus Neumann (Acari: Ixodidae), Ixodes uriae White (Acari: Ixodidae), and Haemaphysalis leporispalustris Packard (Acari: Ixodidae) in Alaska, with I. angustus found on a variety of hosts including domestic companion animals (dogs and cats), small wild mammals, and humans. Ixodes angustus were active from April through October with peaks in adult and nymphal activity observed in summer months (mainly July). Although no known human pathogens were detected, Babesia microti-like parasites and candidatus Ehrlichia khabarensis were identified in ticks and small mammals. The only human pathogen detected (B. burgdorferi s.s.) was found in a tick associated with a dog that had recently traveled to New York, where Lyme disease is endemic. This study highlights the value of a combined passive and active tick surveillance system to detect introduced tick species and pathogens and to assess which tick species and microbes are locally established.

Detección molecular de coinfección por Ehrlichia canis y Ehrlichia ewingii en un perro en Ecuador

Se presenta el estudio de un perro con sintomatología de Parvovirosis que resultó positivo a los test de inmunocromatografìa para Parvovirus y Ehrlichia canis el cual fue confirmado, a nivel molecular, como positivo para E. canis y E. ewingii. Además del interés que representa este caso desde el punto de vista clínico, la detección mediante PCR de E. ewingii sugiere la presencia de este patógeno fuera de su rango de distribución geográfica natural (México, Guatemala, Guyana, Guayana Francesa y Estados Unidos) y destaca la necesidad de realizar estudios moleculares en garrapatas locales a fin de verificar si éste es un caso aislado en Ecuador o si, por el contrario, existe colonización de E. ewingii en vectores locales.

Rhipicephalus Capensis (Acari: Ixodidae), A geographically restricted South African tick, returning with a human traveler to the United States

Accelerated frequency of recreational travel, globalization of business, and legal and illegal plant and animal trades have contributed to enduring introductions of exotic ticks into the United States. We herein report a new incursion of a female Rhipicephalus capensis on a human traveler returning to Connecticut from South Africa. Natural distribution of R. capensis is restricted to the Western Cape Province and southwestern portion of the Northern Cape Province of South Africa, an area called the Fynbos Biome, and adults of this species primarily parasitize large, wild ungulate hosts. Only one previous international introduction of this tick is documented on imported South African plant material into the United States in 1985. The specimen described here was identified initially by morphological means and subsequently, a partial DNA sequence for the mitochondrial ribosomal RNA gene was generated in a PCR assay, which showed 94.86% identity to an R. capensis sequence in GenBank. We also provide information on several other previously unreported or under-reported incursions by South African ticks into the United States in association with imported Fynbos floricultural materials and speckled Cape tortoises, Chersobius signatus. Documentation of these additional exotic tick species incursions highlights ongoing challenges of the international movement of humans, animals, and other goods carrying ticks of human and veterinary importance.

Ticks and Tick-Borne Pathogens in Domestic Animals, Wild Pigs, and Off-Host Environmental Sampling in Guam, USA

Background: Guam, a United States of America (USA) island territory in the Pacific Ocean, is known to have large populations of ticks; however, it is unclear what the risk is to wildlife and humans living on the island. Dog (Canis familiaris), cat (Felis catus), and wild pig (Sus scrofa) sentinels were examined for ticks, and environmental sampling was conducted to determine the ticks present in Guam and the prevalence of tick-borne pathogens in hosts.

Methods and Results: From March 2019-November 2020, ticks were collected from environmental sampling, dogs, cats, and wild pigs. Blood samples were also taken from a subset of animals. A total of 99 ticks were collected from 27 environmental samples and all were Rhipicephalus sanguineus, the brown dog tick. Most ticks were collected during the dry season with an overall sampling success rate of 63% (95% CI: 42.4–80.6). 6,614 dogs were examined, and 12.6% (95% CI: 11.8–13.4) were infested with at least one tick. One thousand one hundred twelve cats were examined, and six (0.54%; 95% CI: 0.20–1.1) were found with ticks. Sixty-four wild pigs were examined and 17.2% (95% CI: 9.5–27.8) had ticks. In total, 1,956 ticks were collected and 97.4% of ticks were R. sanguineus. A subset of R. sanguineus were determined to be the tropical lineage. The other tick species found were Rhipicephalus microplus (0.77%), Amblyomma breviscutatum (0.77 %), and a Haemaphysalis sp. (0.51%). Blood samples from 136 dogs, four cats, and 64 wild pigs were tested using polymerase chain reaction (PCR) and DNA sequencing methods. Five different tick-borne pathogens with the following prevalences were found in dogs: Anaplasma phagocytophilum 5.9% (95% CI: 2.6–11.3); Anaplasma platys 19.1% (95% CI: 12.9–26.7); Babesia canis vogeli 8.8% (95% CI: 4.6–14.9); Ehrlichia canis 12.5% (95% CI: 7.5–19.3); Hepatozoon canis 14.7% (95% CI: 9.2–28.8). E. canis was detected in one cat, and no tick-borne pathogens were detected in wild pigs. Overall, 43.4% (95% CI: 34.9–52.1) of dogs had at least one tick-borne pathogen. Serological testing for antibodies against Ehrlichia spp. and Anaplasma spp. showed prevalences of 14.7% (95% CI: 9.2–28.8) and 31.6% (95% CI: 23.9–40), respectively.

Conclusion: Four different tick species were found in Guam to include a Haemaphysalis sp., which is a previously unreported genus for Guam. Dogs with ticks have a high prevalence of tick-borne pathogens which makes them useful sentinels.

First Record of Established Populations of the Invasive Pathogen Vector and Ectoparasite Haemaphysalis longicornis (Acari: Ixodidae) in Connecticut, United States

A number of invasive tick species capable of transmitting pathogens have been accidentally introduced into the U.S. in recent years. The invasion and further range expansion of these exotic ticks have been greatly facilitated by frequent global travel and trade as well as increases in legal and illegal importation of animals. We describe the discovery of the first established populations of Haemaphysalis longicornis Neumann and the first fully engorged human parasitizing specimen documented through passive tick surveillance in Fairfield County, Connecticut, U.S. We also report several individual specimens of this invasive arthropod and vector of multiple pathogens of medical and veterinary importance collected through active tick surveillance from three counties (Fairfield, New Haven, and New London). Considering the potential for invasive ticks to transmit numerous native and emerging pathogens, the implementation of comprehensive surveillance programs will aid in prompt interception of these ticks and reduce the risk of infection in humans and wildlife.

Detection of Dermacentor andersoni (Acari: Ixodidae) in Brazil on a Human Traveler Returning from the United States

Only one previous record of an exotic tick on a Brazilian traveler has been reported. Here, we report the detection of Dermacentor andersoni (Stiles) in Brazil while attached to a human traveler returning from the United States. This report is the fifth record of D. andersoni as an exotic tick, and the second record of an exotic tick on a South American traveler.

Enduring Challenge of Invasive Ticks: Introduction of Amblyomma oblongoguttatum (Acari: Ixodidae) into the United States on a Human Traveler Returning from Central America

Introduction of exotic tick vectors of bacteria, protozoa, viruses, and filarial parasites into the United States has accelerated in recent years, primarily because of globalization, increased frequency of travel, and a rise in legal and illegal animal trades. We herein report introduction of a live specimen of Amblyomma oblongoguttatum on a human into the United States from Central America, and we review 4 previous similar incidents. This tick species occurs widely in the neotropics, from western and southern Mexico, southwards through Central America, to the northern half of South America. It is a potential vector of bacterial agents of spotted fever group rickettsioses, raising concern that if A. oblongoguttatum ticks become established in this country, they might also be able to carry pathogens of human and veterinary concern. Given the potential for exotic ticks as vectors of numerous pathogens, proper surveillance, interception, and identification of these ticks are vital to protecting human and veterinary health. Rigorous governmental inspections of imported livestock and pet animals at ports of entry and educating human travelers and medical practitioners about the risks should be part of an overall national tick program.

Genomic Profiling for Piroplasms in Feeding Ixodid Ticks in the Eastern Cape, South Africa

Importation of tick-infected animals and the uncontrollable migration of birds and wild animals across borders can lead to geographical expansion and redistribution of ticks and pathogen vectors, thus leading to the emergence and re-emergence of tick-borne diseases in humans and animals. Comparatively, little is known about the occurrence of piroplasms in ixodid ticks in the Eastern Cape, South Africa, thus necessitating this study, which is aimed at detecting piroplasms (Theileria and Babesia) from feeding tick samples collected from cattle, sheep, and goats in selected sites in the Eastern Cape, South Africa. A total of 1200 feeding ixodid ticks collected from farm animals at selected homesteads were first subjected to molecular identification using mitochondrial 12S ribosomal RNA (rRNA) gene by PCR and were further tested for the presence of piroplasms through amplification of the 18S rRNA gene via nested-PCR followed by sequencing of the PCR products. The results indicated that 853 (71.1%) corresponded to the genus Rhipicephalus, 335 (27.9%) corresponded to genus Amblyomma, and 12 (1%) corresponded to genus Haemaphysalis. Amblyomma hebraeum and Rhipicephalus appendiculatus were the most common identified ticks from this study. The 18S rRNA nested-PCR revealed that 44 (3.7%) samples were confirmed positive for Theileria. A homology search for the generated sequences revealed a high percentage identity of 98–98.9% similarity to T. buffeli, T. orientalis, and T. sergenti in the GenBank. Based on the results obtained herein, we conclude that there is a big diversity of Theileria species; therefore, we suggest that this research should cover more geographical areas in order to reveal the true prevalence of this pathogen in the studied area because this will be a great step in the possible prevention of an outbreak that could have devastating effects on livestock production and human health in both the studied areas and South Africa at large.

The Unexpected Holiday Souvenir: The Public Health Risk to UK Travellers from Ticks Acquired Overseas

Overseas travel to regions where ticks are found can increase travellers' exposure to ticks and pathogens that may be unfamiliar to medical professionals in their home countries. Previous studies have detailed non-native tick species removed from recently returned travellers, occasionally leading to travel-associated human cases of exotic tick-borne disease. There are 20 species of tick endemic to the UK, yet UK travellers can be exposed to many other non-native species whilst overseas. Here, we report ticks received by Public Health England's Tick Surveillance Scheme from humans with recent travel history between January 2006 and December 2018. Altogether, 16 tick species were received from people who had recently travelled overseas. Confirmed imports (acquired outside of the UK) were received from people who recently travelled to 22 countries. Possible imports (acquired abroad or within the UK) were received from people who had recently travelled to eight European countries. Species-specific literature reviews highlighted nine of the sixteen tick species are known to vector at least one tick-borne pathogen to humans in the country of acquisition, suggesting travellers exposed to ticks may be at risk of being bitten by a species that is a known vector, with implications for novel tick-borne disease transmission to travellers.

Ticks on the Channel Islands and implications for public health

The Channel Islands are British Crown dependencies located in the English Channel to the west of the Normandy coast in northern France. Whilst there have been studies investigating tick occurrence and distribution in different habitats on the mainland of the UK and in France, the Channel Islands have been relatively understudied. As such, little is known about whether the sheep tick, Ixodes ricinus, is present, and whether there is a potential risk of Lyme borreliosis on the Channel Islands. To ascertain the presence of I. ricinus on the three largest islands in the archipelago: Jersey, Guernsey and Alderney, surveys of ticks questing in the vegetation and ticks feeding on hosts were undertaken during April and May 2016. Across all three islands, the highest numbers of ticks were found in woodland habitats. Ixodes ricinus was the predominant questing tick species found on Jersey, and Ixodes ventalloi the most common questing tick species on Alderney and Guernsey, with little or no evidence of questing I. ricinus on either island. During field studies on small mammals, I. ricinus was the predominant tick species feeding on Jersey bank voles (Myodes glareolus caesarius), with Ixodes hexagonus the most common species infesting hedgehogs on Guernsey. We propose that the greater diversity of small mammals on Jersey may be important in supporting immature stages of I. ricinus, in contrast to Guernsey and Alderney. Morphological identification of tick species was confirmed by PCR sequencing based on amplification of the cytochrome c oxidase subunit one (cox1) gene (COI DNA barcoding). To date, there have been few records of human tick bites in the Channel Islands, suggesting that the current risk from tick-borne disease may be low, but continued reporting of any human tick bites, along with reporting of cases of Lyme borreliosis will be important for continued assessment of the impact of tick-borne diseases in the Channel Islands.

Progress, challenges, and the role of public engagement to improve tick-borne disease literacy

Vector-borne diseases have increased worldwide, facilitated by globalization and variations in climate. Tick and tick-borne disease researchers, veterinarians, medical practitioners, and public health specialists are working to share their expertise on tick ecology, disease transmission, diagnostics, and treatment in order to control tick-borne epidemics and potential pandemics. This review will be a brief overview of the current status of tick-borne diseases, challenges on the scientific and public fronts, and the role of public engagement in improving citizen education within the context of ticks and tick-borne disease research.