Operational Considerations for Using Deer-Targeted 4-Poster Tick Control Devices in a Tick-borne Disease Endemic Community.

CONTEXT: In the northeastern United States, recommendations to prevent diseases spread by black-legged ticks ( Ixodes scapularis ) and lone star ticks ( Amblyomma americanum ) often rely on individuals to use personal protection or yard-based strategies. The 4-Poster deer treatment stations (4-Posters) suppress tick populations by treating deer hosts with acaricide, potentially offering a community-wide approach for reducing tick-borne diseases in endemic areas. The 4-Poster deployment logistics in mainland community settings are not well documented but are needed for future public health tick control efforts. PROGRAM: As part of a public health research effort to design a population-based 4-Poster effectiveness study aimed at reducing tick-borne disease incidence, TickNET researchers partnered with the Town of Ridgefield (Connecticut) to understand the feasibility and operational logistics of deploying 4-Posters on public land within a residential community to inform future public health interventions by municipalities or vector control agencies. IMPLEMENTATION: We deployed three 4-Posters on a municipal property from July to December 2020 and used motion-activated cameras to record wildlife activity nearby. We documented per-device operational details, costs, materials consumed, and animal activity. EVALUATION: Operation of 4-Posters was feasible, and device challenges were easily remedied. Deer visitation and heavy nontarget animal use were documented at all devices. Unexpectedly, monthly corn consumption was not correlated with monthly deer-view days. The monthly cost per device was US $1279 or US $305 per hectare with an average 21 minutes of weekly service time. DISCUSSION: Use of 4-Posters by communities, public health agencies, or vector control programs may be a practicable addition to tick management programs in tick-borne disease endemic areas in the Northeast. Such programs should carefully consider local and state regulations, follow manufacturer and pesticide label guidelines, and include wildlife monitoring. High labor costs incurred in this project could be mitigated by training vector control agency or municipality staff to service 4-Posters.

Evaluation of anti-tick efficiency in rabbits induced by DNA vaccines encoding Haemaphysalis longicornis lipocalin homologue.

Haemaphysalis longicornis is an obligate haematophagous ectoparasite, transmitting a variety of pathogens, which brings great damage to human health and animal husbandry development. Lipocalins (LIP) are a family of proteins that transport small hydrophobic molecules and also involve in immune regulation, such as the regulation of cell homeostasis, inhibiting the host's inflammatory response and resisting the contractile responses in host blood vessels. Therefore, it is one of the candidate antigens for vaccines. Based on previous studies, we constructed the recombinant plasmid pcDNA3.1-HlLIP of LIP homologue from H. longicornis (HlLIP). ELISA results showed that rabbits immunized with pcDNA3.1-HlLIP produced higher anti-rHlLIP antibody levels compared with the pcDNA3.1 group, indicating that pcDNA3.1-HlLIP induced the humoral immune response of host. Adult H. longicornis infestation trial in rabbits demonstrated that the engorgement weight, oviposition and hatchability of H. longicornis fed on rabbits immunized with pcDNA3.1-HlLIP decreased by 7.07%, 14.30% and 11.70% respectively, compared with that of the pcDNA3.1 group. In brief, DNA vaccine of pcDNA3.1-HlLIP provided immune protection efficiency of 30% in rabbits. This study demonstrated that pcDNA3.1-HlLIP can partially protect rabbits against H. longicornis, and it is possible to develop a new candidate antigen against ticks.

Utilisation of indigenous knowledge to control ticks in goats: a case of KwaZulu-Natal Province, South Africa.

Local indigenous knowledge (IK) informs decision-making about fundamental aspects of life. The inclusion of indigenous knowledge is increasingly becoming a topical subject to enhance livestock veterinary care. The objective of the current study was to explore the extent of utilisation of indigenous knowledge to control ticks in goats. There was an association (P < 0.05) between the use of IK and gender, with males using IK (76.58%) more than females. The association between age distribution and IK use was (P < 0.05); however, farmers above the age of 50 years were using IK more than all group ages. Farmers ranked the purposes of using IK differently (P < 0.05). Ectoparasites were ranked as the most important constraint limiting goat productivity. Ticks were ranked as the most important external parasites. Amblyomma tick species were ranked as the most important amongst the tick species, followed by Rhipicephalus evertsi evertsi ticks. A significant population of farmers (80.7%) are dependent on the use of tick sprays, whereas others used injections (3.3%). Cissus quadrangularis L. (Inhlashwana) was singled out as the most used ethno-veterinary plant to control ticks with a frequency of (64%), followed by Gomphocarpus physocarpus E. Mey (Uphehlacwathi) (55.9%). The probability of keeping goats in wet rangelands (P < 0.05) was 3.04 times more likely to influence the extent of IK use compared to their contemporaries in the dry rangeland. Male farmers keeping goats (P < 0.01) were 2.95 more likely to influence the extent of use of IK than females. The type of rangeland, gender, age, residing on farm and also having the herbalist in the locality were the most common factors that influenced the extent of IK utilisation.

Repellency effect of flumethrin pour-on formulation against vectors of Crimean-Congo haemorrhagic fever.

BACKGROUND: Ticks are able to transmit important diseases to humans, including Rocky Mountain spotted fever, Q fever, Crimean-Congo haemorrhagic fever, summer Russian encephalitis, and relapsing fever. AIMS: To determine the repellency effect of 1% flumethrin pour-on formulation against hard ticks. METHODS: The concentration of flumethrin pour-on formulation was 1 mg/10 kg body weight and was administered on the dorsal midline from the head to the base of the tail. The livestock included cows, goats, oxen and sheep in 2 villages in Ardabil Province, Islamic Republic of Iran. RESULTS: We studied 200 livestock comprising 5 age groups (< 2, 3-4, 5-6, 7-8 and >8 years). The main hard ticks identified were Hyalomma species (62.5%) and Rhipicephalus bursa (37.5%). In the treatment village, the maximum number of ticks per animal was 11.6 in oxen, 9.5 in sheep, 8.9 in goats and 8.6 in cattle. The repellency effect of flumethrin remained for 2 months. CONCLUSIONS: Flumethrin provided 2 months protection against hard ticks. Therefore, it could be used in the livestock industry. Control of ticks is important for prevention of disease transmission.

Ectoparasite load in the crested porcupine Hystrix cristata Linnaeus, 1758 in Central Italy.

The crested porcupine Hystrix cristata is a large body-sized rodent, occurring in Europe only in the Italian Peninsula, where it may have been introduced in early Medieval times. Its parasite fauna is currently poorly known and limited to few anecdotal observations. We have analyzed the ectoparasite load of 165 crested porcupines from Tuscany and Latium (Central Italy). Both captured and road-killed individuals were checked for fleas and ticks. Overall, only 39 porcupines were infested by four species of ticks and five of fleas. Abundance of ectoparasites was higher in areas with higher habitat richness, with respect to densely wooded areas. The most frequent species was the flea Pulex irritans (25%), whose prevalence peaked in winter probably because of optimal abiotic conditions in the porcupine's den. The remaining species of both hard ticks (Rhipicephalus bursa, Pholeoixodes hexagonus, and Ixodes ventalloi) and fleas (Paraceras melis, Ctenocephalides canis, Dasypsyllus gallinulae, and Hystrichopsylla talpae), all with prevalence lower than 5%, could be due to den sharing with other vertebrates, mainly carnivores such as, e.g., red foxes and badgers. The second most prevalent species was the generalist tick Ixodes ricinus (21%). An adult male-biased parasitism for ticks has been detected, suggesting a possible role of testosterone related immune-depressive effect. The low richness in dominant ectoparasite species, built up by locally acquired generalist taxa, provides support to the allochthonous origin of this rodent in Italy.

Efficacy and safety of geranium-oregano-thymol formulations to control of dog tick Rhipicephalus sanguineus sensu lato under laboratory and field conditions.

The present study evaluated, in laboratory and field, the efficacy and safety of formulations of Pelargonium graveolens (geranium - G), Origanum majorana (oregano - O) commercial essential oils (EO) and thymol (T) to control of Rhipicephalus sanguineus sensu lato. In the laboratory, three formulas (A: 2% tween 80%, B: powder and C: nanoemulsion) by a mixture of these components (GOT) were prepared and evaluated, and the best one was used to assess its safety and field application against R. sanguineus s. l. on naturally infested dogs. Besides the major compounds of the EO used were identified. The results of the lab study showed that formula A (2.5 g of each G + O + T + 2% tween 80 to complete 100 mL) was significantly more effective than the other two formulas tested and exhibited highly effective adulticidal, larvicidal, and ovicidal activity against R. sanguineus s.l. Significant LC50 and LC90 values of GOT were evaluated (13.4 and 21.5 mg/mL, respectively) for the adulticidal activity, (2.81 and 4.46 mg/mL, respectively) for ovicidal activity and (2.44 and 4.45 mg/mL, respectively) for larvicidal activity. The safety of formula A has been proven by the absence of its cytotoxicity on a cell line of human epidermoid carcinoma. Citronella and carvacrol were the major compounds identified in the commercial essential oils of P. graveolens and O. majorana, respectively. Formula A was used in a field control trial for almost 8 months, during the tick infestation season (April to November, 2022). Fourteen naturally infested dogs were divided into two groups, each with seven dogs. One group received formula A spraying five times during an experiment that continued for 8 months, while the other group received treatment with commercially available malathion acaricide. The animals were sprayed on five occasions throughout the experiment (April, June, July, August, and September). The results showed a substantial percentage of effectiveness after the first application of formula A with a 99.3% reduction in tick count at day 28 post-application (PA). In the case of severe infestation 60 days after the first application of formula A (more than 180 ticks per dog), the second application was done, achieving an efficacy of 54.9% at day 3 PA, so an emergency spray was done at day 5 PA to combat the rest of the tick infestation, achieving efficacy of 99% after 3 days. Consequently, a regular spray (third, fourth, and fifth application) was done every 35 days. This regular spray revealed 100% effectiveness at 14 days PA. Biochemical parameters of treated dogs were evaluated to confirm the safety of formula A. Creatinine, ALT, and albumin of the dogs treated with formula A were within the normal range of dogs, while urea and AST were higher than the normal range. In conclusion, formula A can safely treat R. sanguineus s.l. infestations in dogs with regular application every 5 weeks.

[Zoonoses from ticks and fleas in dogs and cats]. / Zoönosen van teken- en vlooien bij honden en katten.

Fleas and ticks may transmit zoonotic diseases. This is an overview of tick- and flea-borne zoonoses where dogs and cats are involved in the epidemiology.

The East Indies reptile tick Amblyomma helvolum Koch, 1844 (Acari: Ixodidae), taxonomy, biology and new host records, including the first record of human infestation.

Amblyomma helvolum is a widespread, generalist ectoparasite of reptiles in the oriental region, and has the potential to become highly invasive should it be inadvertently introduced outside its native range through the exotic pet trade. All life stages of A. helvolum are re-characterised morphologically and the first examples of nanism (dwarfism) and gynandromorphy (male and female tissue in one animal) for the species are described. Eighteen new hosts records are presented for A. helvolum, including the first case of human infestation. The taxonomy, distribution, ecology, phenology, disease associations, and invasion biology of the species are also discussed.

Putative target sites in synganglion for novel ixodid tick control strategies.

Acaricide resistance is a global problem that has impacts worldwide. Tick populations with broad resistance to all commercially available acaricides have been reported. Since resistance selection in ticks and their role in pathogen transmission to animals and humans result in important economic and public health burden, it is essential to develop new strategies for their control (i.e., novel chemical compounds, vaccines, biological control). The synganglion is the tick central nervous system and it is responsible for synthesizing and releasing signaling molecules with different physiological functions. Synganglion proteins are the targets of the majority of available acaricides. In this review we provide an overview of the mode-of-action and resistance mechanisms against neurotoxic acaricides in ticks, as well as putative target sites in synganglion, as a supporting tool to identify new target proteins and to develop new strategies for tick control.

Desiccant Dusts, With and Without Bioactive Botanicals, Lethal to Rhipicephalus (Boophilus) microplus Canestrini (Ixodida: Ixodidae) in the Laboratory and on Cattle.

The exotic southern cattle fever tick, Rhipicephalus (Boophilus) microplus (Canestrini) (Ixodida: Ixodidae), since its eradication from the United States in 1943, made a strong incursion into Texas, beginning 2016. The pest is arguably the most economically detrimental ectoparasite of cattle, Bos taurus L., worldwide. Current R. (B.) microplus control mostly relies on conventional synthetic acaricides to which the ixodid has been developing resistance. Our study demonstrates that commercially available desiccant dust products, with and without bioactive botanical additives, are strongly lethal, when applied dry, against larval R. (B.) microplus in the laboratory, and after being released on dust-treated cattle. Deadzone (renamed Celite 610, a diatomaceous earth product), Drione (silica gel + pyrethrins + piperonyl butoxide synergist), and EcoVia (silica gel + thyme oil), each prophylactically prevented larval R. (B.) microplus from attaching to and feeding on stanchioned calves. Desiccant dust-based products are less likely than conventional synthetic acaricides to decline in terms of efficacy as a result of ixodid resistance, and other desiccant dust advantages, including extended residual, flexibility in terms of application methods, environmental, animal, and human safety, and possible compatibility with organic, or 'green', production systems, are discussed. We anticipate that the desiccant dusts we evaluated, and others not included in this study (e.g., kaolin, perlite, and silica gel) will be effective when used with other control tactics in integrated pest management approaches for controlling R. (B.) microplus (and other ixodid species).

Efficacy of fluralaner chewable tablets (Bravecto®) against Asian longhorned tick (Haemaphysalis longicornis) infestations of dogs.

BACKGROUND: The parthenogenic reproductive ability of Haemaphysalis longicornis, facilitating quick life cycle completion and rapid geographic spread and its pathogen vector potential make infestations a risk to human and canine health. Two 90-day studies were initiated to evaluate the efficacy of a single fluralaner administration for the treatment and prevention of H. longicornis infestations on dogs. METHODS: Dogs were randomly assigned (10 dogs/group) to either an untreated control group or a group treated once (Day 0) with 13.64% w/w fluralaner chewable tablets (Bravecto®) at the minimum label dose rate of 25 mg/kg. Each dog was infested with approximately 50 H. longicornis ticks on Days -9 or -6 and on Days -2, 28, 58 and 88. A different US tick isolate was used in each study. Tick counts were completed on Days -7 or -4, 2, 30, 60 and 90. The primary efficacy criterion was a 90% reduction in arithmetic mean tick counts between the treated and control groups. For between-group comparisons at any assessment, at least six control dogs were required to retain at least 25% of the infestation dose (13 live ticks). RESULTS: Pre-study infestations demonstrated susceptibility of all study dogs to challenge with H. longicornis. At each subsequent assessment in both studies, at least seven untreated control dogs retained ≥ 25% of the challenge, demonstrating adequate infestations for each efficacy calculation. On Days 2, 30, 60 and 90 the mean live tick infestation rate (number of ticks recovered from each dog/infesting challenge of each dog) of untreated control dogs ranged from 27.8 to 60.8%. No live ticks, free or attached, were found on any fluralaner-treated dog in either study. Between-group differences were statistically significant (P ≤ 0.0002) at each assessment. CONCLUSION: At the minimum recommended label dose rate of 25 mg/kg, fluralaner chewable tablets were 100% effective in eliminating H. longicornis ticks from dogs infested at the time of treatment. Complete efficacy against both US isolates of this tick was maintained through 90 days following a single treatment. Therefore, fluralaner is a treatment of choice for protecting dogs against this invasive tick species.

Experimental oral delivery of the systemic acaricide moxidectin to free-ranging white-tailed deer (Artiodactyla: Cervidae) parasitized by Amblyomma americanum (Ixodida: Ixodidae).

Orally delivered, host-targeted, systemic acaricide treatment has potential to be an effective areawide tick abatement strategy. Past efforts using ivermectin for livestock were reported effective at controlling both Amblyomma americanum (L.) and Ixodes scapularis Say on Odocoileus virginianus (Zimmermann). However, the labeled 48-day withdrawal period for human consumption largely prevented utilization of this strategy targeting I. scapularis in autumn, when peak adult host-seeking activity coincides with regulated white-tailed deer hunting seasons. The modern-day compound moxidectin is the active ingredient in the pour-on formulation Cydectin (5 mg moxidectin/ml; Bayer Healthcare LLC), with a labeled 0-day withdrawal period for human consumption of treated cattle. We sought to re-examine the systemic acaricide approach for tick management by determining if we could successfully deliver Cydectin to free-ranging white-tailed deer. Over 2 yr in late spring/early summer, coinciding with adult and nymphal A. americanum activity, we fed Cydectin-coated corn to free-ranging white-tailed deer in coastal Connecticut. Through serum analysis, we documented moxidectin levels at or above those previously reported effective for control of ectoparasites (5-8 ppb for moxidectin and ivermectin) in 24 of 29 white-tailed deer captured (83%) while exposed to treated corn. While we did not document differences in burdens of parasitizing A. americanum based on moxidectin sera levels, we did document fewer engorged specimens on deer with increased sera levels. The systemic use of moxidectin for tick management in critical reproductive hosts has the potential to be effective in an areawide capacity while also permitting human consumption of treated venison.

[Flea and tick control in dogs and cats]. / Bestrijding van vlooien en teken bij hond en kat.

Fleas and ticks may cause skin problems in dogs and cats and transmit (zoonotic) diseases. This is an overview about the present situation of the ectoparasites control.

Modelling habitat suitability of the invasive tick Rhipicephalus microplus in West Africa.

Ticks have medical and economic importance due to their ability to transmit pathogens to humans and animals. In tropical and sub-tropical countries, tick-borne diseases (TBD) are among the most important diseases affecting livestock and humans. The fast spread of ticks and TBD requires a quick development and application of efficient prevention and/or control programs. Therefore, prior investigations on TBD and related vectors epidemiology, for instance, through accurate epidemiological models, are mandatory. This study aims to develop models to forecast suitable habitat for Rhipicephalus microplus distribution in West Africa. Tick occurrences were assembled from 10 different studies carried out in six West African countries in the past decade. Six statistical models (maximum entropy in a single model and generalised linear model, generalised additive model, random forest, boosted regression tree and support vector machine model in an ensemble model) were applied and compared to predict the habitat suitability of R. microplus distribution in West Africa. Each model was evaluated with the area under the receiver operating characteristic curve (AUC), the true skill statistic (TSS) and the Boyce index (BI). The selected models had good performance according to their AUC (above .8), TSS (above .7) and BI (above .8). Temperature played a key role in MaxEnt model, whereas normalised difference vegetation index (NDVI) was the most important variable in the ensemble model. The model predictions showed coastal countries of West Africa as more suitable for R. microplus. However, some Sahelian areas seems also favourable. We stress the importance of vector surveillance and control in countries that have not yet detected R. microplus but are in the areas predicted to host suitable habitat. Indeed, awareness-raising and training of different stakeholders must be reinforced for better prevention and control of this tick in these different countries according to their status.

Flea and tick treatment satisfaction, preference, and adherence of dog owners in the United States, United Kingdom, and Australia who treated their dog with fluralaner.

Background: An extended duration flea and tick medication of the isoxazoline class (fluralaner) was introduced in 2014 in the United States and other countries. A survey was developed in 2016 to gauge dog owner adherence with veterinary recommendations around the administration of preventive flea and tick medications. Current fluralaner-using dog owners were also asked to compare their experience with opinions on monthly flea and tick products. Aim: To survey dog owners who were current users of fluralaner on their opinions, experiences, and attitudes around the administration of flea and tick medications to their dogs in light of current veterinarian recommendations. Methods: Dog owners in the United States (US), United Kingdom (UK), and Australia that gave fluralaner oral chews to their dogs were asked to compare their experience using fluralaner (12-week dosing) and monthly flea and tick medications. The survey responses of dog owners in the UK and Australia were compared against responses to a similar survey conducted in the US in 2017. Surveys were completed by dog owners who were in the clinic for any reason other than a sickness visit. Additionally, veterinarians that prescribed fluralaner from all three countries provided their annual flea and tick treatment recommendation for dogs. Results: A sample of veterinarians from the US, UK, and Australia that prescribe fluralaner recommend that dog owners obtain approximately 12 months of flea protection per year and 9-12 months of tick protection per year. A variable proportion of owners (22%-90%) reported that their dog participates in outdoor and social activities associated with an increased flea and tick exposure risk. A similarly variable proportion of owners reported prior experience of finding fleas (24%-50%) or ticks (18%-35%) on their dogs. All participating owners treated their dogs currently with fluralaner and most (68%-77%) had previously treated their dog with monthly flea and tick products. The convenience of 12-week dosing and less frequent dosing were the most frequently identified product qualities associated with their choice of an extended effect flea and tick treatment. Conclusion: Most veterinarians surveyed in this survey recommended year-round use of a flea and tick medication for dogs in the US, UK, and Australia. Dog owners recalled the veterinary recommendation for flea and tick prevention as 8-10 months per year. Most dog owners from the clinics in the US, UK, and Australia had used shorter-acting (monthly) flea/tick medications previously. The majority of those who currently gave fluralaner doses to their dogs were "satisfied" or "very satisfied" with the extended duration flea and tick product. Preference for a 12-week duration medication over monthly re-treatment was also high (82%-92%) in all three countries and was associated with convenience.

A comparative analysis of heartworm medication use patterns for dogs that also receive ectoparasiticides.

BACKGROUND: Heartworm medications and many oral or topical flea and tick products are provided as monthly doses while a newer oral flea/tick product, fluralaner (BRAVECTO® Chew), is re-dosed at a 12-week interval. This study focused on whether there was a difference in the number of heartworm medication doses that were purchased in the 12-months follow-up period for dogs that receive either fluralaner or other flea/tick medications that are dosed monthly. METHODS: Clinic transaction records of heartworm medication purchases for over 200,000 dogs were examined to compare the purchase of heartworm preventative protection by dog owners that also receive flea and tick medications of differing efficacy durations. RESULTS: Annual purchases of heartworm medication for dogs by owners that receive a flea and tick medication dosed at 12-week intervals was incrementally higher than the number of doses purchased for dogs receiving monthly flea and tick medications. The average number of monthly doses per year was slightly over 7 months for both categories of product. The distribution of purchases of monthly doses was also similar between groups. CONCLUSIONS: Dog owners who purchase a longer-acting flea and tick medication purchase as much heartworm medication annually for their dogs as dog owners who purchase monthly flea and tick medication. On average, dog owners who gave their dog fluralaner obtained significantly more months of heartworm preventative protection compared with dog owners who gave their dog a monthly flea and tick medication, although the biological significance of this increase in doses is very small.

Upcoming and future strategies of tick control: a review.

Ticks are distributed worldwide and significantly impact human and animal health. Due to severe problems associated with the continuous use of acaricides on animals, integrated tick management is recommended. Increasing public health concern over the tick-borne diseases demands the strategic control of ticks on animals that transmit diseases to human beings. Immunological control of tick vector of Kyasanur Forest Disease (KFD) on cattle and other wild reservoir hosts is one of the possible alternative strategy for reducing the transmission of KFD to man. Chemical-vaccine synergies have been demonstrated and a combination of chemical and vaccine for tick and tick-borne disease control has been identified as a sustainable option. Studies have suggested the possibility of vaccine strategies directed towards both tick control and transmission of pathogens. Besides tick vaccine, use of endosymbionts, which are essential for the survival of arthropod hosts, for the control of tick vectors will be one of the targeted areas of research in near future. India with huge natural resources of herbs and other medicinal plants, the possibilities of developing herbal acaricides is discussed. The future of research directed towards target identification is exciting because of new and emerging technologies for gene discovery and vaccine formulation.

Prospects for suppressing transmission of Lyme disease.

A variety of methods have been developed to prevent human infection by the Lyme disease spirochete in the northeastern United States, mainly based on the observations that nymphal Ixodes dammini serve as vector, that deer serve as hosts for the reproductive stage of this tick, that white-footed mice serve as the reservoir of infection, and that nymphs are most abundant in early summer and must attach for 2 days before infection is transmitted. Methods for personal protection included seasonal avoidance of infested sites, the use of repellants, and prompt removal of attached ticks. Destruction of mouse habitat, but not of mice, was locally effective. Nondestructive acaricidal treatment of deer proved ineffective, but the elimination of these hosts resulted in reduced transmission after several years. Treatment of mice by means of acaricide-impregnated bedding material effectively reduced transmission.

Ticks associated with armadillo (Euphractus sexcinctus) and anteater (Myrmecophaga tridactyla) of Emas National Park, State of Goias, Brazil.

This study was conducted in October 1998 and November 1999 in the Emas National Park (131,868 ha), a savanna-type cerrado region situated in the far south of Goias State, Brazil, near the geographic center of South America (15 degrees -23 degrees S; 45 degrees -55 degrees W). Animals were captured with the aid of nets and anesthetized (15 mg/kg ketamine + 1 mg/kg xylasine) in order to collect ticks for identification and to establish laboratory colonies. They included giant anteaters (Myrmecophaga tridactyla) (n = 4) and yellow armadillos (Euphractus sexcinctus) (n = 6). Free-living ticks (larvae, nymphs, and adults) were collected from the field by using a 1 x 2-m flannel cloth. Free-living ticks were identified as Amblyomma sp., A. cajennense, and A. triste. Adult ticks collected from anteaters were identified as Amblyomma cajennense and A. nodosum and from armadillos as A. pseudoconcolor and A. nodosum. The relevance of these host-tick relationships to possible mechanisms underlying emergence of tick-borne pathogens of importance to public health is discussed.

Use of a sentinel host system to study the questing behavior of Ixodes spinipalpis and its role in the transmission of Borrelia bissettii, human granulocytic ehrlichiosis, and Babesia microti.

Ixodes spinipalpis maintains Borrelia bissettii spirochetes in Colorado in a cycle involving wood rats and deer mice. This tick has been described as nidicolous, remaining either attached to its rodent hosts or in the rodent nest. Nidicolous ticks pose little risk of pathogen transmission to humans if they do not actively quest for hosts. To investigate the questing potential of I. spinipalpis, sentinel mice were placed in an area where I. spinipalpis had been commonly found on wood rats and deer mice. Concurrently, wild rodent populations were trapped and analyzed for Lyme disease spirochetes, the agent of human granulocytic ehrlichiosis (aoHGE), and Babesia microti. A total of 122 I. spinipalpis larvae and 10 nymphs were found on 19% of 244 sentinel mice. In addition, 4 sentinel mice became infested with Malaraeus telchinus or Orchopeas neotomae fleas. Questing I. spinipalpis were positively associated with woody shrubs and negatively associated with sunny and grassy areas. Four sentinel mice became infected with aoHGE after having been fed upon only by I. spinipalpis larvae. One sentinel mouse became infected with B. bissettii after having an I. spinipalpis nymph feed on it, and one sentinel mouse became coinfected with aoHGE and B. bissettii after it was fed upon by a single I. spinipalpis nymph. These sentinel mouse conversions suggest the possibility that the aoHGE is transovarially transmitted by I. spinipalpis, and that I. spinipalpis is capable of simultaneously transmitting B. bissettii and the aoHGE. The findings that I. spinipalpis quest away from rodent nests and will attach to and infect sentinel mice may be of public health importance. It suggests the potential transmission of the agents of human granulocytic ehrlichiosis and Lyme disease to other hosts by I. spinipalpis, in regions of the western United States where Ixodes pacificus is not found.