Proliferative strongyloidiasis in a colony of colubrid snakes

Strongyloides are small rhabditid nematodes primarily associated with enteric disease in a variety of animal species, including reptiles. Strongyloides spp life stages were associated with a disease outbreak in a large breeding colony of snakes. Multiple Pantherophis and Lampropeltis colubrids exhibited respiratory distress, anorexia, stomatitis, facial deformation, and waning body condition that resulted in death or necessitated euthanasia. Postmortem examinations of 13 snakes revealed epithelial hyperplasia and inflammation of the alimentary and respiratory tracts associated with varying numbers of adult and larval nematodes and embryonated or larvated ova. In a subset of snakes, aberrant nematode migration was also observed in the eye, genitourinary system, coelom, and vasculature. Histomorphology and gross examination of parasitic adult female nematodes from host tissues were consistent with a Strongyloides spp. Sedimented fecal material from 101/160 (63%) snakes housed in the affected facility was positive for nematodes and/or larvated ova. Polymerase chain reaction amplification and sequencing of portions of the 18S and 28S ribosomal ribonucleic acid (RNA) genes and the internal transcribed spacer region of adult female parasites and positive fecal samples supported the diagnosis of strongyloidiasis. Strongyloides spp possess a unique life cycle capable of alternating between parasitic (homogonic) and free-living (heterogonic) stages, resulting in the production of directly infective larvae. Commonly utilized husbandry practices in reptile collections can amplify the numbers of infective larvae generated in the captive environment, increasing the risk for rhabditid hyperinfections. This report documents morbidity, mortality, and non-enteric disease manifestations due to Strongyloides hyperinfections in a captive colubrid snake colony.

The invasive pentastome Raillietiella orientalis in a banded water snake from the pet trade

Raillietiella orientalis is established in Florida and rapidly spreading both geographically and in known host species. A banded water snake (Nerodia fasciata), purchased in Michigan at a regional reptile show, expectorated a pentastome whose morphology and DNA sequence indicated that it was R. orientalis. This event indicates that, through the pet trade, R. orientalis has been spread 1,500 km from its previously known distribution limit. Fecal sample analyses indicated that the snake was shedding large numbers of embryonated eggs for at least several months. The diversity of reptile species that are both known hosts of R. orientalis in Florida and are commonly sold in the pet trade indicates that this invasive pentastome may become a widespread health concern for pet owners and veterinarians.

Infection with the fox lungworm (Crenosoma vulpis) in two dogs from New England - Two clinical reports and updated geographic distribution in North America

Crenosoma vulpis, the fox lungworm, is a helminth parasite endemic to the fox population of New England. Domestic dogs are susceptible to infection via ingestion of snails and slugs. Two dogs from New England were diagnosed with C. vulpis. The predominant clinical sign in both dogs was a chronic cough. Treatment with steroids and antibiotics only temporarily relieved clinical signs. Thoracic radiographs in both dogs revealed bronchial patterns. Endotracheal washes were performed in each dog revealing marked, mixed inflammation consisting mainly of neutrophils with eosinophils in lesser numbers. Helminth larvae could also be visualized on cytology. A fecal flotation revealed helminth larvae in one dog but failed to identify larvae in the second dog. The diagnosis of C. vulpis was confirmed via PCR analysis and sequencing of samples from both endotracheal washes. One dog was treated with fenbendazole (50 mg/kg PO q24h for 14 days), enrofloxacin (13 mg/kg PO q 24 h for 5 days), and a tapering protocol of prednisone (20 mg PO q12h for 5 days, 20 mg PO q24h for 5 days, then 20 mg PO q48h for 10 days). The second dog was treated with fenbendazole (50 mg/kg PO q24h for 10 days) with an additional 7 days of febantel and two doses of milbemycin, achieving complete resolution of clinical signs. This lungworm is becoming increasingly more prevalent in domestic dogs worldwide and may be more prevalent in New England than previously thought. Veterinary practitioners of New England should include this respiratory helminth as a differential in dogs with respiratory signs, and respiratory washes and Baermann fecal examinations are warranted in dogs presenting with non-specific respiratory clinical signs.

A NEW COCCIDIAN (APICOMPLEXA: EIMERIIDAE) IN THE CRITICALLY ENDANGERED CENTRAL AMERICAN RIVER TURTLE (DERMATEMYS MAWII) IN BELIZE

As part of a biannual health examination, coprological samples from 3-mo-old Central American river turtles, Dermatemys mawii (Gray, 1847) in a breeding program in Belize, Central America, revealed a previously undescribed coccidian (Apicomplexa) in 17 of 46 (37%) samples. Of 3 positive fecal samples transported to the University of Florida, coccidian oocysts were observed in 1 sample. Sporulated oocysts were measured and described, and using polymerase chain reaction (PCR), an approximately 400-base pair (bp) region of both the small subunit (18S) ribosomal RNA gene and 1,200-bp region of the internal transcribed spacer (ITS) gene were amplified in all 3 samples and their products were sequenced. For comparative value, the same PCR reactions and amplifications were performed on a fecal sample containing oocysts of Eimeria mitraria obtained from a red-eared slider, Trachemys scripta elegans. Results indicated a new eimerian in D. mawii, Eimeria grayi n. sp.

Gastrointestinal entamoebiasis in captive anurans in North America

Infections with Entamoeba spp. are recognized as a cause of clinical disease in many species including humans and reptiles; however, cases in amphibians are under-reported. Investigation of a mortality event among a captive population of Cranwell's horned frogs Ceratophrys cranwelli at a production facility in Florida, USA, revealed that deaths were due to the newly described Entamoeba species CT1. Infection caused severe necroulcerative gastroenterocolitis with a predilection for the colon. To date, this Entamoeba species has only been described in invasive cane toads Rhinella marina in Australia. Retrospective screening of archived anuran cases from a zoological pathology service identified 8 cases from captive populations that had histological evidence of gastrointestinal entamoebiasis. Molecular characterization was positive in 3 cases. Two cases, 1 in a Puerto Rican crested toad Peltophryne lemur and 1 in an Amazon milk frog Trachycephalus resinifictrix, showed 100% homology to E. ranarum and 1 case in a White's tree frog Litoria caerulea showed 100% homology to Entamoeba sp. CT1. This is the first report of novel Entamoeba sp. CT1 being associated with clinical disease in anurans within North America and also the first report of this Entamoeba species causing disease within managed collections as far back as 2003.

Angiostrongylus cantonensis (rat lungworm) in Florida, USA: current status

Angiostrongylus cantonensis has been found in Florida, USA, from the panhandle in the north to Miami and surrounding areas in the southern parts of the state, in both definitive and intermediate hosts in a limited studies completed in 2015. Additional studies have identified this parasite in a variety of intermediate hosts, both native and non-native gastropod species, with new host species recorded. Many areas in Florida with higher A. cantonensis prevalence were those with a high human population density, which suggests it is a matter of time before human infections occur in Florida. Case reports in the state currently involve non-human primates and include a gibbon and orangutan in Miami. Here, we report the current status of A. cantonensis in the state, as well as the infection in a capuchin monkey and presumptive infection in a red ruffed lemur in Gainesville, Florida.

Detection of heartworm antigen without cross-reactivity to helminths and protozoa following heat treatment of canine serum

BACKGROUND

Detection of Dirofilaria immitis, or heartworm, through antigen in sera is the primary means of diagnosing infections in dogs. In recent years, the practice of heat-treating serum prior to antigen testing has demonstrated improved detection of heartworm infection. While the practice of heat-treating serum has resulted in earlier detection and improved sensitivity for heartworm infections, it has been suggested that heat treatment may cause cross reactivity with A. reconditum and intestinal helminth infections of dogs. No studies have assessed the potential cross-reactivity of these parasites with heartworm tests before and after heat treatment using blood products and an appropriate gold standard reference.

METHODS

Canine sera (n=163) was used to evaluate a heartworm antigen-ELISA (DiroCHEK®) and potential cross-reactivity with common parasitic infections. The heartworm status and additional parasite infections were confirmed by necropsy and adult helminth species verified morphologically or by PCR, and feces evaluated by centrifugal fecal flotation.

RESULTS

Intestinal parasites were confirmed in 140 of the dogs by necropsy, and 130 by fecal flotation. Acanthocheilonema reconditum microfilariae were confirmed in 22 dogs. Prevalence of heartworm infection confirmed by necropsy was 35.6% (58/163). In the 105 dogs without heartworms, specificity remained unchanged at 100% both before and after heat treatment despite confirmed infections with A. reconditum, Ancylostoma caninum, Ancylostoma brasiliense, Trichuris vulpis, Toxocara canis, Dipylidium caninum, Spirometra mansonoides, Macracanthorynchus ingens, Cystoisospora sp., Giardia sp., and Sarcocystis sp.

CONCLUSIONS

These findings suggest that the use of heat treatment improves sensitivity of heartworm tests and is unlikely to cause false positive antigen results due to Acanthocheilonema reconditum, intestinal helminths, and protozoal parasites in dogs.

Case Report: Invasive Pentastomes, Raillietiella orientalis (Sambon, 1922), in a Free-Ranging Banded Water Snake (Nerodia fasciata) in North Central Florida, USA

Raillietiella orientalis is an obligate, crustacean parasite that resides in the respiratory tract of definitive snake hosts. Common throughout southeastern Asia and Australia, R. orientalis is believed to have been introduced into southern Florida, United States along with Burmese pythons (Python bivittatus) in the 1990s. While the invasive range of Burmese pythons is restricted to southern Florida, R. orientalis has advanced north in the state in native snake species. R. orientalis were recovered from the lungs, trachea, oral cavity, and esophagus of an emaciated adult female free-ranging banded water snake (Nerodia fasciata) in north central (Alachua County), Florida, USA. Concurrent findings included the recovery of Ochetosoma sp. trematodes from the oral cavity, and multifocal dermal lesions consistent with snake fungal disease (Ophidiomyces ophiodiicola). This is the first report of R. orientalis in north central Florida, well outside the invasive range of the Burmese python, documenting the substantial northward expansion of the known geographical range of this invasive pentastome in Florida.