Phylogeography of the blacklegged tick (Ixodes scapularis) throughout the USA identifies candidate loci for differences in vectorial capacity.

The blacklegged tick (Ixodes scapularis (Journal of the Academy of Natural Sciences of Philadelphia, 1821, 2, 59)) is a vector of Borrelia burgdorferi sensu stricto (s.s.) (International Journal of Systematic Bacteriology, 1984, 34, 496), the causative bacterial agent of Lyme disease, part of a slow-moving epidemic of Lyme borreliosis spreading across the northern hemisphere. Well-known geographical differences in the vectorial capacity of these ticks are associated with genetic variation. Despite the need for detailed genetic information in this disease system, previous phylogeographical studies of these ticks have been restricted to relatively few populations or few genetic loci. Here we present the most comprehensive phylogeographical study of genome-wide markers in I. scapularis, conducted by using 3RAD (triple-enzyme restriction-site associated sequencing) and surveying 353 ticks from 33 counties throughout the species' range. We found limited genetic variation among populations from the Northeast and Upper Midwest, where Lyme disease is most common, and higher genetic variation among populations from the South. We identify five spatially associated genetic clusters of I. scapularis. In regions where Lyme disease is increasing in frequency, the I. scapularis populations genetically group with ticks from historically highly Lyme-endemic regions. Finally, we identify 10 variable DNA sites that contribute the most to population differentiation. These variable sites cluster on one of the chromosome-scale scaffolds for I. scapularis and are within identified genes. Our findings illuminate the need for additional research to identify loci causing variation in the vectorial capacity of I. scapularis and where additional tick sampling would be most valuable to further understand disease trends caused by pathogens transmitted by I. scapularis.

Population genetics of the Ixodes affinis (Ixodida: Ixodidae) complex in America: new findings and a host-parasite review.

Ticks are hematophagous ectoparasites associated with a wide range of vertebrate hosts. Within this group, the Ixodidae family stands out, in which the Ixodes genus contains at least 245 species worldwide, from which 55 species are present in the Neotropical region. Ixodes affinis, a tick described in 1899, has a wide distribution from the Southern Cone of America to the United States. However, since its description, morphological variability has been reported among its populations. Furthermore, attempts have been made to clarify its status as a species complex using mitochondrial markers, but mainly in restricted populations of South and Central America. Thus, information related to populations of the transition region between the Neotropical and Nearctic zones is lacking. For these reasons, the objectives of the study were to evaluate the genetic diversity and structure of I. affinis across the Americas and to compile all the published records of I. affinis in America, to elucidate the host-parasite relationships and to identify their geographical distribution. For this, a phylogeny, and AMOVA analyses were performed to assess the genetic structure of samples obtained by field work in South Carolina, USA and Yucatán, Mexico. A total of 86 sequences were retrieved from a fragment of the 16S region. Phylogeny and genetic structure analysis showed four groups that were geographically and genetically related with high branch support and Fst values, all of them statistically significant. The results obtained support the hypothesis that I. affinis it corresponds to a complex of four species, which must be validated through future morphological comparisons.

Histopathologic reassessment of melanoma and other melanocytic skin lesions excised in 2009 and 2018-2019. / Histopatologisk revurdering av melanom og andre melanocytære hudlesjoner eksidert i 2009 og 2018­19.

BACKGROUND: Histopathological assessment of melanoma and other melanocytic skin lesions can be difficult and can vary between pathologists. MATERIAL AND METHOD: Histopathological slides of 196 melanocytic skin lesions from 2009 and 2018-2019 were obtained from the archive of the Department of Pathology at Oslo University Hospital and classified into six diagnostic categories: 1) benign nevus, 2) irregular/dysplastic nevus, i.e. dysplastic nevus with moderate atypia, 3) nevus with severe atypia, i.e. dysplastic nevus with severe atypia, 4) melanoma in situ, 5) superficial spreading or lentiginous melanoma and 6) nodular melanoma. The slides were then examined independently and blindly by three experienced pathologists and categorised in the same way. Interobserver agreement was assessed with Cohen's kappa, and agreement with the original diagnosis was assessed by the proportion of assessments in the same diagnostic category. RESULTS: The kappa values for the assessments from the three pathologists ranged from 0.45 to 0.50. The proportion of reassessments in agreement with the original diagnostic category was 85.7 % (95 % CI 75.7 to 92.1), 29.2 % (19.9 to 40.5), 27.8 % (20.9 to 36.0), 78.3 % (70.4 to 84.5), 81.2 % (73.7 to 86.9) and 93.3 % (82.1 to 97.7), respectively, i.e. highest for nodular melanoma. The proportion of reassessments in which the diagnosis was more serious or less serious than the original diagnosis was higher and lower, respectively, for slides from 2009 than for slides from 2018-2019. INTERPRETATION: The differences between the pathologists' assessments and deviations from the original diagnoses can be explained by poorly reproducible diagnostic criteria, diagnostic entities with overlapping morphology and increasing awareness of early signs of malignancy. Some evolution in diagnostic practice cannot be ruled out.

Antibodies to Borrelia turicatae in Experimentally Infected Dogs Cross-React with Borrelia burgdorferi Serologic Assays.

Tick-borne relapsing fever (TBRF) is caused by several Borrelia spp. (including Borrelia turicatae), which are primarily transmitted by Ornithodoros ticks. Relapsing fever group species are found worldwide, except for Antarctica. Approximately 500 human cases were reported between 1990 and 2011 in the United States (likely an underestimate), while cases in domestic and wild dogs were reported from Florida, Texas, and Washington. TBRF spirochetes are related to Borrelia burgdorferi, the agent of Lyme borreliosis. Dogs are routinely screened for B. burgdorferi, but it is unknown if infection with TBRF agents produces antibodies cross-reactive with B. burgdorferi assays. These data are critical for accurate surveillance of TBRF and Lyme borreliosis in dogs. In this study, B. burgdorferi-negative dogs were inoculated with B. turicatae, and seroconversion was confirmed by the rBipA (recombinant Borrelia immunogenic protein A) Western blot. Seropositive samples were tested with commercial and veterinary diagnostic laboratory B. burgdorferi-based tests. Borrelia turicatae-seroreactive samples cross-reacted with a whole-cell indirect fluorescent antibody (IFA) test and two multiantigen tests, but not with single-antigen tests using C6. Cross-reactivity with TBRF can confound epidemiology and surveillance efforts and confuse recommendations made by veterinarians for prevention and control. These findings demonstrate the need to critically evaluate results from B. burgdorferi diagnostic tests in the context of the assay type and the animal's geographical location and history of travel, as well as highlighting the need for commercially available specific diagnostic tests for TBRF spirochetes.

Parasitaemia data and molecular characterization of Haemoproteus catharti from New World vultures (Cathartidae) reveals a novel clade of Haemosporida.

BACKGROUND: New World vultures (Cathartiformes: Cathartidae) are obligate scavengers comprised of seven species in five genera throughout the Americas. Of these, turkey vultures (Cathartes aura) and black vultures (Coragyps atratus) are the most widespread and, although ecologically similar, have evolved differences in morphology, physiology, and behaviour. Three species of haemosporidians have been reported in New World vultures to date: Haemoproteus catharti, Leucocytozoon toddi and Plasmodium elongatum, although few studies have investigated haemosporidian parasites in this important group of species. In this study, morphological and molecular methods were used to investigate the epidemiology and molecular biology of haemosporidian parasites of New World vultures in North America. METHODS: Blood and/or tissue samples were obtained from 162 turkey vultures and 95 black vultures in six states of the USA. Parasites were identified based on their morphology in blood smears, and sequences of the mitochondrial cytochrome b and nuclear adenylosuccinate lyase genes were obtained for molecular characterization. RESULTS: No parasites were detected in black vultures, whereas 24% of turkey vultures across all sampling locations were positive for H. catharti by blood smear analysis and/or PCR testing. The phylogenetic analysis of cytochrome b gene sequences revealed that H. catharti is closely related to MYCAMH1, a yet unidentified haemosporidian from wood storks (Mycteria americana) in southeastern USA and northern Brazil. Haemoproteus catharti and MYCAMH1 represent a clade that is unmistakably separate from all other Haemoproteus spp., being most closely related to Haemocystidium spp. from reptiles and to Plasmodium spp. from birds and reptiles. CONCLUSIONS: Haemoproteus catharti is a widely-distributed parasite of turkey vultures in North America that is evolutionarily distinct from other haemosporidian parasites. These results reveal that the genetic diversity and evolutionary relationships of avian haemosporidians are still being uncovered, and future studies combining a comprehensive evaluation of morphological and life cycle characteristics with the analysis of multiple nuclear and mitochondrial genes will be useful to redefine the genus boundaries of these parasites and to re-evaluate the relationships amongst haemosporidians of birds, reptiles and mammals.

Possible Role of Fish as Transport Hosts for Dracunculus spp. Larvae.

To inform Dracunculus medinensis (Guinea worm) eradication efforts, we evaluated the role of fish as transport hosts for Dracunculus worms. Ferrets fed fish that had ingested infected copepods became infected, highlighting the importance of recommendations to cook fish, bury entrails, and prevent dogs from consuming raw fish and entrails.

Opportunistic Sampling of Roadkill as an Entry Point to Accessing Natural Products Assembled by Bacteria Associated with Non-anthropoidal Mammalian Microbiomes.

Few secondary metabolites have been reported from mammalian microbiome bacteria despite the large numbers of diverse taxa that inhabit warm-blooded higher vertebrates. As a means to investigate natural products from these microorganisms, an opportunistic sampling protocol was developed, which focused on exploring bacteria isolated from roadkill mammals. This initiative was made possible through the establishment of a newly created discovery pipeline, which couples laser ablation electrospray ionization mass spectrometry (LAESIMS) with bioassay testing, to target biologically active metabolites from microbiome-associated bacteria. To illustrate this process, this report focuses on samples obtained from the ear of a roadkill opossum (Dideiphis virginiana) as the source of two bacterial isolates (Pseudomonas sp. and Serratia sp.) that produced several new and known cyclic lipodepsipeptides (viscosin and serrawettins, respectively). These natural products inhibited biofilm formation by the human pathogenic yeast Candida albicans at concentrations well below those required to inhibit yeast viability. Phylogenetic analysis of 16S rRNA gene sequence libraries revealed the presence of diverse microbial communities associated with different sites throughout the opossum carcass. A putative biosynthetic pathway responsible for the production of the new serrawettin analogues was identified by sequencing the genome of the Serratia sp. isolate. This study provides a functional roadmap to carrying out the systematic investigation of the genomic, microbiological, and chemical parameters related to the production of natural products made by bacteria associated with non-anthropoidal mammalian microbiomes. Discoveries emerging from these studies are anticipated to provide a working framework for efforts aimed at augmenting microbiomes to deliver beneficial natural products to a host.

Species composition of Culicoides (Diptera: Ceratopogonidae) in the Ridge and Valley region of Tennessee, USA.

Biting midges in the genus Culicoides Latreille (Diptera: Ceratopogonidae) are known to transmit many pathogens of veterinary and medical concern. Although much work has been done globally and in certain regions of North America, Culicoides spp. research in rural Appalachia is limited. To begin characterizing the distribution and community structure of Culicoides spp. in Appalachia, we surveyed 2 distinct sites in the Ridge and Valley ecoregion of northeastern Tennessee, USA, from April 2021-September 2021. Culicoides spp. were sampled using 2 methods: Centers for Disease Control ultraviolet LED light traps and potential larval habitat substrate collection (coupled with water chemistry values). Site 1 was dominated by natural features, and Site 2 was a beef cattle operation. During 96 trap nights, a total of 1,568 Culicoides were collected, representing 24 species. Site 1 yielded the highest diversity, with 24 species, while Site 2 yielded 12 species. Overall, the most abundant species in light traps were C. stellifer Coquillett (44%), C. bergi Cochrane (18%), C. haematopotus Malloch (12%), and C. debilipalpis Lutz (11%). From substrate sampling, 8 species were identified. Culicoides haematopotus was the most abundant and was collected during each sampling period. Water chemistry values taken at the time of substrate collection were not significantly related to which Culicoides spp. emerged from a given substrate. Our results indicate a diverse community of Culicoides spp. in our study area, however, further work is needed to identify Culicoides species composition across a variety of landscapes in Appalachia and inform research on vector presence and associated vector disease dynamics.

Otterly diverse - A high diversity of Dracunculus species (Spirurida: Dracunculoidea) in North American river otters (Lontra canadensis).

The genus Dracunculus contains numerous species of subcutaneous parasites of mammals and reptiles. In North America, there are at least three mammal-infecting species of Dracunculus. Reports of Dracunculus infections have been reported from river otters (Lontra canadensis) since the early 1900s; however, little is known about the species infecting otters or their ecology. Most reports of Dracunculus do not have a definitive species identified because females, the most common sex found due to their larger size and location in the extremities of the host, lack distinguishing morphological characteristics, and few studies have used molecular methods to confirm identifications. Thus, outside of Ontario, Canada, where both D. insignis and D. lutrae have been confirmed in otters, the species of Dracunculus in river otters is unknown. In the current study, molecular characterization of nematodes from river otters revealed a high diversity of Dracunculus species. In addition to confirming D. insignis infections, two new clades were detected. One clade was a novel species in any host and the other was a clade previously detected in Virginia opossums (Didelphis virginiana) from the USA and a domestic dog from Spain. No infections with D. lutrae were detected and neither new lineage was genetically similar to D. jaguape, which was recently described from a neotropical otter (Lontra longicaudis) from Argentina. These data also indicate that Dracunculus spp. infections in otters are widespread throughout Eastern North America. Currently the life cycles for most of the Dracunculus spp. infecting otters are unknown. Studies on the diversity, life cycle, and natural history of Dracunculidae parasites in wildlife are important because the related parasite, D. medinensis (human Guinea worm) is the subject of an international eradication campaign and there are increasing reports of these parasites in new geographic locations and new hosts, including new species in humans and domestic dogs.

Immobilization of Raccoons (Procyon lotor) with Nalbuphine, Medetomidine, and Azaperone.

Chemical immobilization is widely used by wildlife and veterinary professionals for the safe handling of animals. A combination of nalbuphine (40 mg/mL), azaperone (10 mg/mL), and medetomidine (10 mg/mL), known as NAM, is a low-volume combination with field immobilization practicality and fewer regulations restricting its use in the US than some other drug combinations. We evaluated the safety and effectiveness of NAM as an immobilizing agent for raccoons (Procyon lotor). From May 2021 to February 2022, 16 adult raccoons were captured in cage traps and immobilized with 0.3 mL NAM intramuscularly (12 mg nalbuphine, 3 mg medetomidine, and 3 mg azaperone, regardless of body weight). After administration, time to sedation was measured; body temperature, heart rate, respiratory rate, and oxygen saturation were monitored and recorded every 5 min for 20 min. Each raccoon was weighed; the dose administered was calculated (range 2.2-4.1 mg/kg, mean 3 mg/kg). Mean induction time was 6 min (4-17 min); time to recovery following administration of 15 mg atipamezole, 7.5 mg naltrexone for reversal, was 10 min (6-18 min). Heart rate, oxygen saturation, and respiration rate remained steady during immobilization. Rectal temperature steadily declined. Overall, NAM appeared to be a practical option for raccoon immobilization, providing rapid induction and reversal as well as adequate sedation for short-term handling and minimally invasive sampling.

A survey of piroplasms in white-tailed deer (Odocoileus virginianus) in the southeastern United States to determine their possible role as Theileria orientalis hosts.

In 2017, clinical disease and mortality in cattle associated with Theileria orientalis Ikeda was reported in Virginia, U.S. The exotic tick, Haemaphysalis longicornis, is a competent vector for this species. White-tailed deer (Odocoileus virginianus) are commonly infested with H. longicornis in the eastern U.S. and are also infected with several genotypes of piroplasms such as a Theileria sp. (often called Theileria cervi-like), Babesia odocoilei, and Babesia sp. H10. However, it is currently unknown if deer are susceptible to T. orientalis and can act as potential hosts. In this study, we tested 552 white-tailed deer samples from the southeastern U.S. to determine the presence of T. orientalis. We used a PCR-RFLP to test 293 (53%) of these samples to distinguish between piroplasm genera. A total of 189 white-tailed deer were positive with Theileria, 47 were positive with Babesia, and 57 did not amplify. Because this assay does not determine species, we sequenced 30 random samples targeting a fragment of the 18S rRNA gene. Although a high diversity of Theileria and Babesia spp. were detected, none were T. orientalis. All 552 samples were then screened with a T. orientalis specific real-time PCR protocol, but none were positive for T. orientalis. Our data suggests that white-tailed deer are commonly infected with piroplasm species but not T. orientalis.

The wild life of ticks: Using passive surveillance to determine the distribution and wildlife host range of ticks and the exotic Haemaphysalis longicornis, 2010-2021.

BACKGROUND: We conducted a large-scale, passive regional survey of ticks associated with wildlife of the eastern United States. Our primary goals were to better assess the current geographical distribution of exotic Haemaphysalis longicornis and to identify potential wild mammalian and avian host species. However, this large-scale survey also provided valuable information regarding the distribution and host associations for many other important tick species that utilize wildlife as hosts. METHODS: Ticks were opportunistically collected by cooperating state and federal wildlife agencies. All ticks were placed in the supplied vials and host information was recorded, including host species, age, sex, examination date, location (at least county and state), and estimated tick burden. All ticks were identified to species using morphology, and suspect H. longicornis were confirmed through molecular techniques. RESULTS: In total, 1940 hosts were examined from across 369 counties from 23 states in the eastern USA. From these submissions, 20,626 ticks were collected and identified belonging to 11 different species. Our passive surveillance efforts detected exotic H. longicornis from nine host species from eight states. Notably, some of the earliest detections of H. longicornis in the USA were collected from wildlife through this passive surveillance network. In addition, numerous new county reports were generated for Amblyomma americanum, Amblyomma maculatum, Dermacentor albipictus, Dermacentor variabilis, and Ixodes scapularis. CONCLUSIONS: This study provided data on ticks collected from animals from 23 different states in the eastern USA between 2010 and 2021, with the primary goal of better characterizing the distribution and host associations of the exotic tick H. longicornis; however, new distribution data on tick species of veterinary or medical importance were also obtained. Collectively, our passive surveillance has detected numerous new county reports for H. longicornis as well as I. scapularis. Our study utilizing passive wildlife surveillance for ticks across the eastern USA is an effective method for surveying a diversity of wildlife host species, allowing us to better collect data on current tick distributions relevant to human and animal health.

Investigating Flubendazole as an Anthelmintic Treatment for Guinea Worm (Dracunculus medinensis): Clinical Trials in Laboratory-Reared Ferrets and Domestic Dogs in Chad.

Dracunculus medinensis (Guinea worm [GW]), a zoonotic nematode targeted for eradication, has been managed using interventions aimed at humans; however, increases in domestic dog GW infections highlight the need for novel approaches. We conducted two clinical trials evaluating the efficacy of subcutaneously injected flubendazole (FBZ) as a treatment of GW infection. The first trial was conducted administering FBZ to experimentally infected ferrets; the second trial involved administering FBZ or a placebo to domestic dogs in the Republic of Tchad (Chad). We found contrasting results between the two trials. When adult gravid female GW were recovered from ferrets treated with FBZ, larvae presented in poor condition, with low to no motility, and an inability to infect copepods. Histopathology results indicated a disruption to morulae development within uteri of worms from treated animals. Results from the trial in Chadian dogs failed to indicate significant treatment of or prevention against GW infection. However, the difference in treatment intervals (1 month for ferrets and 6 months for dogs) or the timing of treatment (ferrets were treated later in the GW life-cycle than dogs) could explain different responses to the subcutaneous FBZ injections. Both trials provided valuable data guiding the use of FBZ in future trials (such as decreasing treatment intervals or increasing the dose of FBZ in dogs to increase exposure), and highlighted important lessons learned during the implementation of a field-based, double-blinded randomized control trial in Chadian dogs.

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.

Susceptibility of anurans, lizards, and fish to infection with Dracunculus species larvae and implications for their roles as paratenic hosts.

Dracunculus spp. are parasitic nematodes that infect numerous species of mammals and reptiles. The life cycles of Dracunculus species are complex, and unknowns remain regarding the role of paratenic and transport hosts in transmission to definitive hosts. We had two primary objectives: to assess the susceptibility of several species of anurans, lizards, and fish as paratenic hosts for Dracunculus species, and to determine the long-term persistence of Dracunculus infections in African clawed frogs (Xenopus laevis). Animals were orally exposed to copepods infected with infectious third-stage larvae (L3s) of either Dracunculus insignis or D. medinensis. Dracunculus L3s were recovered from four anuran species, two lizard species, and one fish species, demonstrating that Dracunculus can infect tissues of a diversity of species. In long-term persistence trials, D. medinensis L3s were recovered from African clawed frogs tissues up to 58 days post-infection, and D. insignis L3s were recovered up to 244 days post-infection. Our findings regarding the susceptibility of novel species of frogs, lizards, and fish to infection with Dracunculus nematodes, and long-term persistence of L3s in paratenic hosts, address pressing knowledge gaps regarding Dracunculus infection in paratenic hosts and may guide future research regarding the transmission of Dracunculus to definitive mammalian hosts.

Copepod consumption by amphibians and fish with implications for transmission of Dracunculus species.

Parasitic nematodes in the genus Dracunculus have a complex life cycle that requires more than one host species in both aquatic and terrestrial habitats. The most well-studied species, Dracunculus medinensis, is the causative agent of human Guinea worm disease (dracunculiasis). There are several other Dracunculus species that infect non-human animals, primarily wildlife (reptiles and mammals). The classic route of D. medinensis transmission to humans is through the ingestion of water containing the intermediate host, a cyclopoid copepod, infected with third-stage larvae (L3s). However, many animal hosts (e.g., terrestrial snakes, dogs) of other Dracunculus sp. appear unlikely to ingest a large number of copepods while drinking. Therefore, alternative routes of infection (e.g., paratenic or transport hosts) may facilitate Dracunculus transmission to these species. To better understand the role of paratenic and transport hosts in Dracunculus transmission to animal definitive hosts, we compared copepod ingestion rates for aquatic species (fish, frogs [tadpoles and adults], and newts) which may serve as paratenic or transport hosts. We hypothesized that fish would consume more copepods than amphibians. Our findings confirm that African clawed frogs (Xenopus laevis) and fish consume copepods, but that fish ingest, on average, significantly higher numbers (68% [34/50]) than adult African clawed frogs (36% [18/50]) during a 24-h time period. Our results suggest that amphibians and fish may play a role in the transmission of Dracunculus to definitive hosts. Still, additional research is required to determine whether, in the wild, fish or frogs are serving as paratenic or transport hosts. If so, they may facilitate Dracunculus transmission. However, if these animals simply act as dead-end hosts or as means of copepod population control, they may decrease Dracunculus transmission.

A multi-seasonal study investigating the phenology, host and habitat associations, and pathogens of Haemaphysalis longicornis in Virginia, U.S.A.

Understanding the abiotic and biotic variables affecting tick populations is essential for studying the biology and health risks associated with vector species. We conducted a study on the phenology of exotic Haemaphysalis longicornis (Asian longhorned tick) at a site in Albemarle County, Virginia, United States. We also assessed the importance of wildlife hosts, habitats, and microclimate variables such as temperature, relative humidity, and wind speed on this exotic tick's presence and abundance. In addition, we determined the prevalence of infection with selected tick-borne pathogens in host-seeking H. longicornis. We determined that the seasonal activity of H. longicornis in Virginia was slightly different from previous studies in the northeastern United States. We observed nymphal ticks persist year-round but were most active in the spring, followed by a peak in adult activity in the summer and larval activity in the fall. We also observed a lower probability of collecting host-seeking H. longicornis in field habitats and the summer months. In addition, we detected H. longicornis on several wildlife hosts, including coyote (Canis latrans), eastern cottontail (Sylvilagus floridanus), raccoon (Procyon lotor), Virginia opossum (Didelphis virginiana), white-tailed deer (Odocoileus virginianus), woodchuck (Marmota monax), and a Peromyscus sp. mouse. This latter record is the first detection of a larval H. longicornis on a North American rodent host important to the enzootic maintenance of tick-borne pathogens of humans and animals. Finally, we continued to detect the exotic piroplasm parasite, Theileria orientalis Ikeda, in H. longicornis as well as other pathogens, including Rickettsia felis, Anaplasma phagocytophilum (AP-1), and a Hepatozoon sp. previously characterized in Amblyomma americanum. These represent some of the first detections of arthropod-borne pathogens native to the United States in host-seeking H. longicornis. These data increase our understanding of H. longicornis biology in the United States and provide valuable information into the future health risks associated with this tick and pathogens.

Surveillance for diseases, pathogens, and toxicants of muskrat (Ondatra zibethicus) in Pennsylvania and surrounding regions.

Using diagnostic data and contemporary sampling efforts, we conducted surveillance for a diversity of pathogens, toxicants, and diseases of muskrats (Ondatra zibethicus). Between 1977 and 2019, 26 diagnostic cases were examined from Kansas and throughout the Southeast and Mid-Atlantic, USA. We identified multiple causes of mortality in muskrats, but trauma (8/26), Tyzzer's disease (5/6), and cysticercosis (5/26) were the most common. We also conducted necropsies, during November 2018-January 2019 Pennsylvania muskrat trapping season, on 380 trapper-harvested muskrat carcasses after the pelt was removed. Tissue samples and exudate were tested for presence of or exposure to a suite of pathogens and contaminants. Gastrointestinal tracts were examined for helminths. Intestinal helminths were present in 39.2% of necropsied muskrats, with Hymenolepis spp. (62%) and echinostome spp. (44%) being the most common Molecular testing identified a low prevalence of infection with Clostridium piliforme in the feces and Sarcocystis spp. in the heart. We detected a low seroprevalence to Toxoplasma gondii (1/380). No muskrats were positive for Francisella tularensis or Babesia spp. Cysticercosis was detected in 20% (5/26) of diagnostic cases and 15% (57/380) of our trapper-harvested muskrats. Toxic concentrations of arsenic, cadmium, lead, or mercury were not detected in tested liver samples. Copper, molybdenum, and zinc concentrations were detected at acceptable levels comparative to previous studies. Parasite intensity and abundance were typical of historic reports; however, younger muskrats had higher intensity of infection than older muskrats which is contradictory to what has been previously reported. A diversity of pathogens and contaminants have been reported from muskrats, but the associated disease impacts are poorly understood. Our data are consistent with historic reports and highlight the wide range of parasites, pathogens and contaminants harbored by muskrats in Pennsylvania. The data collected are a critical component in assessing overall muskrat health and serve as a basis for understanding the impacts of disease on recent muskrat population declines.