Emergence of Thelaziosis Caused by Thelazia callipaeda in Dogs and Cats, United States.

We report 2 autochthonous feline thelaziosis cases caused by the eyeworm Thelazia callipaeda and discuss the spread among dogs in the northeastern United States. Phylogenetic analysis suggests the parasite was introduced from Europe. Adopting a One Health approach is needed to limit further spread of T. callipaeda eyeworms in North America.

Autochthonous Thelazia callipaeda Infection in Dog, New York, USA, 2020.

We report a case of autochthonous infection of the eye worm Thelazia callipaeda in a dog in the northeastern United States. Integrated morphologic identification and molecular diagnosis confirmed the species. Phylogenetic analysis suggested introduction from Europe. The zoonotic potential of this parasite warrants broader surveillance and increased awareness among physicians and veterinarians.

Onchocerca lupi Nematodes in Dogs Exported from the United States into Canada.

The Onchocerca lupi nematode is an emerging helminth capable of infecting pets and humans. We detected this parasite in 2 dogs that were imported into Canada from the southwestern United States, a region to which this nematode is endemic. We discuss risk for establishment of O. lupi in Canada.

Evaluation of parasitic infections with histological and molecular detection in Anoles from St. Kitts.

Anoles are a widely distributed group of reptiles that are also increasing in popularity as a pet animal. These species have been described as paratenic and intermediate hosts for many parasites of veterinary and medical importance. However, while human and animals such as cats and dogs may often interact with anoles, little research has been conducted in terms of assessing the full potential of anoles to harbor parasites of public and veterinary health significance. The current study analyzed the parasites of anoles captured and dissected in St. Kitts, West Indies, to describe the parasitic population within these reptiles and evaluate the potential role of anoles as intermediate/paratenic hosts. From March until May of 2019, samples from 11 anoles were collected following humane euthanasia and evaluated grossly, histologically, and molecularly for the presence of parasites. Histologic evaluation revealed adult ascarids, oxyurids, and spirurids within the stomach, as well as intraluminal adult ascarids within the intestine, and encysted larval trematodes within the intestinal wall. Molecular analysis based on 18S rRNA and ITS2 DNA markers for nematodes and trematodes, respectively, identified Physaloptera sp. (99.4-99.8% identical with Physaloptera turgida, Physaloptera mirandai, Physaloptera retusa, Physaloptera rara) and Platynosomum illiciens (99.7% identical). Phylogenetic analysis of ITS 2 sequences of P. illiciens from this study cladded monophyletically with the same species from different geographic areas and hosts. Our study highlights the importance of understanding the role anoles play in the life cycles of less well-studied parasites, and the potential of these animals to act as intermediate or paratenic hosts.

NOVEL REPORT OF THE EUROPEAN VARIANT OF ECHINOCOCCUS MULTILOCULARIS IN COYOTES (CANIS LATRANS) IN NEW YORK STATE.

Echinococcus multilocularis is a zoonotic cestode that can infect wildlife, domestic animals, and humans. In humans, infection with the larval stage of the parasite causes the disease alveolar echinococcosis, which can be fatal if left untreated. Surveillance for the parasite in New York State occurred during the 2021-2022 coyote (Canis latrans) hunting season. Fecal samples and the gastrointestinal tracts (GIT) from 43 coyote carcasses were collected from hunters and trappers across 8 counties. Fecal samples were screened for E. multilocularis DNA using a multiplex PCR. Three samples tested positive for E. multilocularis DNA. Subsequently, adult cestodes were collected from GIT samples using the sedimentation, filtration, and counting technique. Phylogenetic analysis of DNA sequences from the nad2 and cob genes from individual worms indicated these New York sequences cluster with E. multilocularis sequences from Europe. This is the first report of adult E. multilocularis cestodes in New York State, as well as the first detection of the European haplotype of E. multilocularis in wildlife in the northeastern United States.

Taenia crassiceps Cysticercosis in a Wild Muskrat and a Domestic Dog in the Northeastern United States.

Taenia crassiceps is a parasite of wild canids and dogs that serve as definite hosts, harboring the adult cestode, whereas rodents are the intermediate hosts in which the metacestode/cysticercus/larval stage occurs. Fecal-oral transmission ensures the parasite's lifecycle. At times, dogs and humans act as accidental intermediate hosts. Despite the public health concern this parasite warrants, its epidemiology remains unclear. In this report, we document the occurrence of metacestodes of T. crassiceps in a muskrat (Ondatra zibethicus) and a domestic dog from the northeastern United States, a development that necessitates increased awareness and surveillance to tackle this disease of "one health" significance. Taenia crassiceps cysticercosis was confirmed in an adult male muskrat in February 2018 and in a 4-year-old female spayed Staffordshire Bull Terrier in December 2020. Parasitological and histopathologic examination of both cases revealed cysticerci with the characteristic rostellar hook morphology that aided in Taenia species identification. In the muskrat case specifically, partial sequencing of the mitochondrial cytochrome oxidase gene confirmed the species identity as T. crassiceps. We report T. crassiceps occurrence in a muskrat in New York State for the first time and document a case presentation in a domestic dog from New Jersey that was infected with metacestode stages of this parasite. Given the detection of this parasite in the northeastern United States, T. crassiceps infection, which otherwise is considered a rare disease, should be on the radar of veterinary, medical and wildlife biologists for timely diagnosis and interventions.

Evaluation of Fecal Egg Count Tests for Effective Control of Equine Intestinal Strongyles.

The American Association of Equine Practitioners strongly advocates evidence-based intestinal strongyle control in horses. It recommends targeted treatment of all heavy egg shedders (>500 eggs per gram (EPG) of feces), while the low shedders (0-200 EPG) are left untreated. As 50-75% of adult horses in a herd are low shedders, preventing them from unnecessary anthelmintic exposure is critical for tackling resistance. There are various fecal egg count (FEC) techniques with many modifications and variations in use, but none is identified as a gold standard. The hypothesis of the study was that the diagnostic performance of 12 commonly used quantitation methodologies (three techniques with four variants) differs. In this regard, method comparison studies were performed using polystyrene beads as proxy for intestinal strongyle eggs. Mini-FLOTAC-based variants had the lowest coefficient of variation (CV%) in bead recovery, whereas McMaster variants had the highest. All four variants of Mini-FLOTAC and the NaNO3 1.33 specific gravity variant of modified Wisconsin followed a linear fit with R2 > 0.95. In contrast, the bead standard replicates for modified McMaster variants dispersed from the regression curve, causing a lower R2. The Mini-FLOTAC method seems less influenced by the choice of floatation solution and has better repeatability parameters and linearity for bead standard recovery. For FEC tests with high R2 (>0.95) but that underestimated the true bead count, a correction factor (CF) was determined to estimate the true count. Finally, the validity of CF was analyzed for 5 tests with R2 > 0.95 to accurately quantify intestinal strongyle eggs from 40 different horses. Overall, this study identified FEC methodologies with the highest diagnostic performance. The limitations in standardizing routine FEC tests are highlighted, and the importance of equalization of FEC results is emphasized for promoting uniformity in the implementation of parasite control guidelines.

Infection and tissue distribution of highly pathogenic avian influenza A type H5N1 (clade 2.3.4.4b) in red fox kits (Vulpes vulpes).

Avian influenza H5N1 is a highly pathogenic virus that primarily affects birds. However, it can also infect other animal species, including mammals. We report the infection of nine juvenile red foxes (Vulpes vulpes) with Highly Pathogenic Avian Influenza A type H5N1 (Clade 2.3.4.4b) in the spring of 2022 in the central, western, and northern regions of New York, USA. The foxes displayed neurologic signs, and examination of brain and lung tissue revealed lesions, with brain lesions ranging from moderate to severe meningoencephalitis. Analysis of tissue tropism using RT-PCR methods showed a comparatively lower Ct value in the brain, which was confirmed by in situ hybridization targeting Influenza A RNA. The viral RNA labelling was highly clustered and overlapped the brain lesions, observed in neurons, and grey matter. Whole viral genome sequences obtained from the affected foxes were subjected to phylogenetic and mutation analysis to determine influenza A clade, host specificity, and potential occurrence of viral reassortment. Infections in red foxes likely occurred due to preying on infected wild birds and are unlikely due to transmission between foxes or other mammals.

Echinococcus multilocularis in urban coyotes, Alberta, Canada.

Echinococcus multilocularis is a zoonotic parasite in wild canids. We determined its frequency in urban coyotes (Canis latrans) in Alberta, Canada. We detected E. multilocularis in 23 of 91 coyotes in this region. This parasite is a public health concern throughout the Northern Hemisphere, partly because of increased urbanization of wild canids.

Prostaglandin E2 produced by Entamoeba histolytica signals via EP4 receptor and alters claudin-4 to increase ion permeability of tight junctions.

Entamoeba histolytica is a protozoan parasite that causes amebic dysentery characterized by severe watery diarrhea. Unfortunately, the parasitic factors involved in the pathogenesis of diarrhea are poorly defined. Prostaglandin E(2) (PGE(2)) is a host lipid mediator associated with diarrheal diseases. Intriguingly, E. histolytica produces and secretes this inflammatory molecule. We investigated the mechanism whereby ameba-derived PGE(2) induces the onset of diarrhea by altering ion permeability of paracellular tight junctions (TJs) in colonic epithelia. PGE(2) decreased barrier integrity of TJs in a dose- and time-dependent manner, as measured by transepithelial resistance. PGE(2) signals were selectively transduced via the EP4 receptor. Furthermore, PGE(2) signaling decreased TJ integrity, as revealed by EP receptor-specific agonist and antagonist studies. Loss of mucosal barrier integrity corresponded with increased ion permeability across TJs. Subcellular fractionation and confocal microscopy studies highlighted a significant spatial alteration of an important TJ protein, claudin-4, that corresponded with increased sodium ion permeability through TJs toward the lumen. Moreover, PGE(2)-induced luminal chloride secretion was a prerequisite for alterations at TJs. Thus, the gradient of NaCl created across epithelia could serve as a trigger for osmotic water flow that leads to diarrhea. Our results highlight a pathological role for E. histolytica-derived PGE(2) in the onset of diarrhea.

MORPHOMETRY OF FIRST-STAGE LARVAE OF ORTHOSTRONGYLUS MACROTIS (NEMATODA: PROTOSTRONGYLIDAE), LUNGWORM OF WILD UNGULATES FROM WESTERN NORTH AMERICA.

Orthostrongylus macrotis (Dikmans, 1931) is a protostrongylid lungworm in wild ungulates from western North America, including mule and Columbia black-tailed deer, pronghorn, and rarely moose and elk. The lack of morphological data for certain developmental stages of O. macrotis and the unresolved taxonomic status of the genus indicate a more detailed morphological characterization of the species is necessary. We provide a detailed description of first-stage larvae (L1) of O. macrotis including morphological, morphometric, and molecular data. Species identity was confirmed based on molecular sequence data from the internal transcribed spacer subunit 2 (ITS-2) and large subunit (28S) rDNA. A fragment of the cytochrome oxidase c subunit 1 (COI) was also sequenced, followed by the determination of genetic distance and phylogenetic analyses. Integrated data describing L1 of O. macrotis contributes to a broader understanding of the parasite fauna of wild ungulates from North America and may be of relevance for a future revision of the genus. Further, we outline information for differentiation among species of North American protostrongylids, with typical spike-tailed L1s, circulating among free-ranging and semi-domestic ungulates.

Hypoxia-inducible factor signaling provides protection in Clostridium difficile-induced intestinal injury.

BACKGROUND & AIMS: Clostridium difficile is the leading cause of nosocomial infectious diarrhea. Antibiotic resistance and increased virulence of strains have increased the number of C difficile-related deaths worldwide. The innate host response mechanisms to C difficile are not resolved; we propose that hypoxia-inducible factor (HIF-1) has an innate, protective role in C difficile colitis. We studied the impact of C difficile toxins on the regulation of HIF-1 and evaluated the role of HIF-1alpha in C difficile-mediated injury/inflammation. METHODS: We assessed HIF-1alpha mRNA and protein levels and DNA binding in human mucosal biopsy samples and Caco-2 cells following exposure to C difficile toxins. We used the mouse ileal loop model of C difficile toxin-induced intestinal injury. Mice with targeted deletion of HIF-1alpha in the intestinal epithelium were used to assess the effects of HIF-1alpha signaling in response to C difficile toxin. RESULTS: Mucosal biopsy specimens and Caco-2 cells exposed to C difficile toxin had a significant increase in HIF-1alpha transcription and protein levels. Toxin-induced DNA binding was also observed in Caco-2 cells. Toxin-induced HIF-1alpha accumulation was attenuated by nitric oxide synthase inhibitors. In vivo deletion of intestinal epithelial HIF-1alpha resulted in more severe, toxin-induced intestinal injury and inflammation. In contrast, stabilization of HIF-1alpha with dimethyloxallyl glycine attenuated toxin-induced injury and inflammation. This was associated with induction of HIF-1-regulated protective factors (such as vascular endothelial growth factor-alpha, CD73, and intestinal trefoil factor) and down-regulation of proinflammatory molecules such as tumor necrosis factor and Cxcl1. CONCLUSIONS: HIF-1alpha protects the intestinal mucosa from C difficile toxins. The innate protective actions of HIF-1alpha in response to C difficile toxins be developed as therapeutics for C difficile-associated disease.

Strongyloides papillosus causes sudden death in weaned calves on New York dairies.

CASE DESCRIPTION: Outbreaks of sudden death in apparently healthy weaned dairy calves due to Strongyloides papillosus parasitism were diagnosed on 2 separate and independent New York (NY) dairies. CLINICAL FINDINGS: Most calves were found dead; however, 1 calf observed while dying showed signs of tachycardia, tachypnea, vocalization, and convulsions shortly before death. In 6 affected heifers that underwent post-mortem examination, precocious bilaterally symmetric mammary gland enlargement was seen. A portion of their parasitized living cohorts also demonstrated similar mammary gland enlargement. A diagnosis of S papillosus hyperinfection was made based upon the presence of high numbers of S papillosus ova in feces, and confirmation by S papillosus-specific PCR assays. Consistent histopathological findings in affected calves included generalized mammary gland vascular congestion, interstitial edema and hemorrhage with ductal hyperplasia. Mild multifocal cardiomyocyte degeneration was found in 5 of 14 calves examined. Factors believed to contribute to the parasite's environmental amplification and host hyperinfection included group housing on wood shavings and high environmental temperatures and humidity. TREATMENT AND OUTCOME: Treatment of calves with doramectin pour-on stopped mortality and resolved the udder enlargement. CLINICAL RELEVANCE: Similar outbreaks have previously been described in Japan and South Bohemia (Czech Republic), where researchers hypothesized that sudden death may be due to fatal arrhythmia caused by a parasite-associated cardiotoxin. This report highlights the importance of including S papillosus among the differential diagnoses for sudden death alone or together with precocious udder enlargement in calves kept in confinement housing.

Infectious disease surveillance of apparently healthy horses at a multi-day show using a novel nanoscale real-time PCR panel.

In the United States, horses are used for a variety of purposes including recreation, exhibition, and racing. As farm, performance, and companion animals, horses are a unique species from a zoonotic disease risk perspective, and the risks of subclinical infections spreading among horses can pose challenges. Using a nanoscale real-time PCR platform, we investigated the prevalence of 14 enteric pathogens, 11 Escherichia coli genes, and 9 respiratory pathogens in fecal samples from 97 apparently healthy horses at a multi-day horse event. In addition, sugar flotation test was performed for fecal parasites. E. coli f17 was commonly detected, prevalent in 59% of horses, followed closely by Streptococcus equi subsp. zooepidemicus (55%). Additional pathogens recognized included betacoronavirus, Campylobacter jejuni, Cryptosporidium sp., E. coli O157, equine adenovirus 1, equine rhinitis B virus, and others. The use of PCR data may overestimate the true prevalence of these pathogens but provides a sensitive overview of common pathogens present in healthy horses. Our results prompt the continued need for practical biosecurity measures at horse shows, both to protect individuals interacting with these horses and to minimize transmission among horses.

Retrospective study of canine endoparasites diagnosed by fecal flotation methods analyzed across veterinary parasitology diagnostic laboratories, United States, 2018.

BACKGROUND: Companion animal endoparasites play a substantial role in both veterinary medicine and public health. Updated epidemiological studies are necessary to identify trends in occurrence and distribution of these parasites, and their associated risk factors. This study aimed to assess the occurrence of canine endoparasites  retrospectively, using fecal flotation  test data available through participating academic veterinary parasitology diagnostic laboratories across the United States of America (USA). METHODS: Canine fecal flotation records from ten veterinary diagnostic laboratories located in nine states in the USA acquired from January 1, 2018, to December 31, 2018, were included. RESULTS: A total of 4692 fecal flotation test results were obtained, with a majority comprised of client-owned dogs (3262; 69.52%), followed by research dogs (375; 8.00%), and shelter dogs (122; 2.60%). Samples from 976 (20.80%) dogs were positive for at least one parasite, and co-infections of two or more parasites were found in 3.82% (179/4692) of the samples. The five most commonly detected parasites were: Giardia sp., (8.33%; 391/4692), Ancylostomatidae (5.63%; 264/4692), Cystoisospora spp. (4.35%; 204/4692), Toxocara canis (2.49%;117/4692), and Trichuris vulpis (2.43%; 114/4692). Various other internal parasites, including gastrointestinal and respiratory nematodes, cestodes, trematodes, and protozoans were detected in less than 1% of samples. CONCLUSIONS: These data illustrate the importance of parasite prevention, routine fecal screening, and treatment of pet dogs. Additionally, pet owners should be educated about general parasite prevalence, prevention, and anthelmintic treatment regimens to reduce the risks of environmental contamination and zoonotic transmission.

Role of EP4 receptor and prostaglandin transporter in prostaglandin E2-induced alteration in colonic epithelial barrier integrity.

Prostaglandin E(2) (PGE(2)) is a proinflammatory lipid mediator produced in excess in inflammatory bowel disease (IBD). PGE(2) couples to and signals via four different E-prostanoid (EP) receptors, namely EP1, EP2, EP3, and EP4. In this study, we determined a role for PGE(2) and EP4 receptors in altering colonic epithelial barrier integrity. In healthy colonic mucosa, EP4 receptors were localized on apical plasma membrane of epithelial cells at the tip of mucosal folds, whereas, in patients with IBD and in rats with dextran sodium sulfate (DSS)-induced colitis, they were diffusely overexpressed throughout the mucosa. Similarly, expression of EP4 receptor was polarized in T84 colonic epithelial monolayer and mimics the normal epithelium. Apical exposure of T84 monolayer with high levels of PGE(2) decreased barrier integrity, which was abrogated by an EP4 receptor antagonist. To reveal the mechanism of vectorial transport of basally produced PGE(2) toward apical EP4 receptors, we identified prostaglandin transporters (PGT) in human colonic epithelia. PGT were least expressed on epithelial cells at the colonic mucosal folds of control subjects but overexpressed in epithelial cells of patients with IBD or animals with DSS-induced colitis. T84 monolayer also expressed PGT, which increased twofold following stimulation with TNF-α. Importantly, in T84 monolayer stimulated with TNF-α, there was a corresponding increase in the uptake and vectorial transport of (3)H-PGE(2) to the apical surface. Knockdown or pharmacological inhibition of PGT significantly decreased vectorial transport of (3)H-PGE(2). These studies unravel a mechanism whereby EP4 receptor and PGT play a role in PGE(2)-induced alteration of epithelial barrier integrity in colitis.

Diagnostic Methods for Detecting Internal Parasites of Livestock.

Internal parasites are a major concern in livestock production because they can impact the health and well-being of animals clinically and subclinically, and ultimately cause significant production loss. Among these internal parasites are nematodes, tapeworms, flukes, and coccidian protozoans. This review focuses on the diagnostic tests that are routinely performed by veterinarians and diagnostic laboratories, but also highlights recently developed tools that may improve diagnostic capabilities, including molecular and immunodiagnostic tests. Overall, diagnostic tests for parasites of livestock are an integral part of health management practices, and for assessing individual animal and herd health.

Identification of Schistosoma mansoni Infection in a Nonhuman Primate from St. Kitts More than 50 Years after Interruption of Human Transmission.

Transmission of Schistosoma mansoni was interrupted on St. Kitts, a Caribbean island, in the 1950s. With no reported cases since that time and most Biomphalaria spp. snail populations eliminated based on surveys in the 1970s, S. mansoni has been considered eliminated on St. Kitts. In 2019, S. mansoni eggs were found in an African green monkey (Chlorocebus aethiops sabaeus) that originated from St. Kitts. Nonhuman primate (NHP) infections have been considered incidental to human infections, with infections in NHPs resolving with the elimination of S. mansoni in the human population. An NHP with S. mansoni infection suggests that the NHP may be able to maintain a reservoir sylvatic cycle. Alternatively, S. mansoni transmission was not eliminated or S. mansoni has been reintroduced to St. Kitts. The occurrence of an infected NHP from St. Kitts supports the need for continuous monitoring in areas where S. mansoni is considered eliminated.

Canine Toxocariosis: Its prevalence, incidence and occurrence in the Indian subcontinent.

Toxocariosis is an important neglected tropical helminth disease of zoonotic significance for which canids are the definitive hosts. Dogs are also considered the sentinel host for the occurrence of T. canis infections in humans. Therefore, understanding its prevalence in canine population is imperative for any effective disease control in humans. A comprehensive review of literature on the prevalence of T. canis in canids was lacking from the Indian subcontinent which necessitated our efforts to compile available data published on this topic. Data on prevalence, incidence and occurrence of this helminths in canids were presented in this review as tabular format for easy comprehension. Moreover, the data were categorized based on the region where the studies were conducted with an aim to understand the spatial distribution of this parasite in the subcontinent. Factors influencing the regional prevalence/occurrence of T. canis such as type of canids (stray or pet), age, sex, breed, season and the choice of analytical methods were also discussed. In addition, data on the prevalence of T. canis in environmental samples and in zoo canids were also compiled and presented. We anticipate such an exhaustive review of literature available mostly in the journals published from the subcontinent would become a point source of information necessary for prioritizing future surveillance efforts in this region and for making informed policy decision to control this zoonotic helminth infection.

First report of Aelurostrongylus abstrusus in St. Kitts.

A 4-month-old intact male domestic shorthair kitten living in St Kitts, West Indies presented with respiratory distress, cachexia, and mucopurulent nasal discharge. Thoracic radiographs revealed a diaphragmatic hernia. The diaphragmatic hernia as well as subpleural pulmonary nodules suspicious for verminous pneumonia were identified during a postmortem examination. Histology showed multifocal to coalescing pyogranulomatous and eosinophilic pneumonia centered on larvae and morulated eggs. The lesion and nematode morphology were consistent with Aelurostrongylus abstrusus. Although Aelurostrongylus abstrusus has been reported worldwide, this is the first report of a metastrongyloid lungworm in cats in St. Kitts and for the West Indies. This case report should increase the awareness of A. abstrusus pneumonia in cats from St. Kitts and other locations in the eastern Caribbean.