Sarcoptic mange in captive maras: the first known outbreak and complete recovery with colony-wide acaricide treatment

Morphological and molecular characterisation of the nematode parasite Graphidioides affinis (Secernentea: Trichostrongylidae) in Patagonian maras, Dolichotis patagonum, kept in a zoo in Sofia, Bulgaria

Introduction

Patagonian maras, rodents endemic to South America, are classified as a near-threatened species. Various factors affect their health including parasitic diseases. The aim of this study was to perform morphometric, molecular and phylogenetic characterisation of one such parasitic disease agent, the nematode Graphidioides affinis, specimens of which were found in captive Patagonian maras.

Material and Methods

In March 2023, 18 Patagonian maras kept at the Sofia Zoo in Bulgaria were investigated with the use of coprological methods. Following the investigation, the animals were dewormed with the use of albendazole. Dead adult nematodes found in the faeces of dewormed maras were collected and preserved in 70% ethanol, and morphometrically, molecularly and phylogenetically analysed.

Results

The morphometric analyses confirmed the nematodes to be Graphidioides affinis. The partial nucleotide sequences of the small subunit ribosomal rDNA (SSU), the internal transcribe spacer 2 (ITS2) and the large subunit ribosomal DNA (LSU) of G. affinis were obtained. These are the first available nucleotide sequences of this parasite. The phylogenetic analyses of the species showed its distinctiveness in comparison to other gastrointestinal nematodes, as it was grouped separately.

Conclusion

The Patagonian maras kept in a European zoo retained their original parasitofauna which are related to South America.

SARCOPTIC MANGE IN FREE-RANGING NORTH AMERICAN PORCUPINES (ERETHIZON DORSATUM) IN NEW YORK STATE

Sarcoptic mange causes pruritic and crusting dermatitis in a large number of mammalian species with varying population impacts. Between 2016 and 2022, 15 North American porcupines (Erethizon dorsatum) were diagnosed with sarcoptic mange at Cornell University's Janet L. Swanson Wildlife Hospital in Ithaca, New York. Disease severity varied among individuals but all shared a similar unique presentation with thick, pale tan to yellow crusts limited in distribution to the ventral, nonquilled areas of the body, including the ventral abdomen and thorax, distal limbs, and face. The thick, hard nature of the crusts resulted in additional complications in many individuals, including inability to move the jaw and cracking and fissuring of the crusts and skin over joints of the limbs. Mites were plentiful within the crusts, with some burrowing into the epidermis as deep as the stratum spinosum. Secondary bacterial and/or fungal dermatitis were common, resulting in sepsis and death in three of the porcupines. Treatment with avermectins (ivermectin and/or selamectin) for 4-5 wk was successful in 12 cases in combination with other supportive care measures, including subcutaneous fluids, antimicrobials, and analgesics. Porcupines were hospitalized for an average of 18 d (ranging from 7 to 50 d) prior to transfer to a licensed wildlife rehabilitator for continued treatment and eventual release back into the wild.

Sarcoptes scabiei infestation in a captive lowland tapir (Tapirus terrestris): case report, morphological and molecular genetic mite identification

Sarcoptes scabiei (Acari: Sarcoptidae) is a globally distributed parasitic mite species, which causes mange in a broad spectrum of domestic and wild mammals. In the present study, we report a case of chronic S. scabiei infestation in a captive lowland tapir (Tapirus terrestris) held in a multi-species exhibit at Vienna Zoo. The adult male showed clinically manifested mange flare-ups three times at an interval of up to 12 months, diagnosed by positive deep-skin scrapings and successfully treated by oral applications of ivermectin (0.1-0.2 mg/kg body weight) and washings with antimicrobial solutions. Clinical symptoms including pruritus, alopecia, erythema, crusts, and superficial bleedings were limited to the axillar and pectoral region, as well as distal limbs. The affected tapir died from underlying bacterial pneumonia during general anesthesia. Skin scrapings, necropsy, and histopathological analysis of mite material (eggs, larvae, and adults) permitted further morphological and molecular identification. The morphological features described here matched the characteristics for the species S. scabiei and molecular data verified morphological identification. Cross-species transmission plays a key role in the expansion of this neglected emerging panzootic disease and urban wildlife could potentially bridge the gap between free-ranging wildlife reservoirs and zoo animals. However, further examinations are needed to detect the primary source of infestation and discover transmission pathways within the zoo.

The Prophylactic Effect of Ivermectin Treatments on Nematode Infections of Mammals in a Faunistic Park (Northern Italy)

Nematode infections of mammals can spread in zoos and faunistic parks and lead to disease in humans and animals. Group treatment strategies with anthelminthic drugs are common. Still, their effectiveness should be verified by sensitive and specific copromicroscopic analyses. This study assessed longitudinal parasitological monitoring, by FLOTAC® dual technique, in mammals housed in an Italian faunistic park, in order to verify the effectiveness of the two adopted ivermectin prophylactic treatments. Twenty-one species of herbivorous mammals from ten families were treated twice per year with ivermectin in an in-feed formulation (medicated feed containing 1.7 g/ton ivermectin daily, for 30 days in March and November), while 13 species of carnivores and primates from five families were treated once a month with oral or subcutaneous administrations of ivermectin (200 μg/kg body weight (b.w.), from March to November). Fecal samples were collected in June–July and October 2019 (late spring–early summer and autumn sampling groups, respectively). All nematode infections, sustained by Nematodirus spp., Capillaria spp., Trichuris spp., Parascaris spp. and Strongylida, were detected in samples collected from herbivores, presenting prevalence rates of infection of 17.3% (9/52), 15.4% (8/52), 15.4% (8/52), 5.8% (3/52), and 3.8% (2/52), respectively. All carnivores and primates tested negative. The general linear mixed model showed that nematode eggs’ excretion in herbivores were influenced by sampling and sampling-host family interaction. Results showed that frequency and dose of prophylactic treatments in herbivores should be improved according to host and parasite taxonomic groups. The treatment adopted in carnivores and primates, together with hygienic management, was effective in nematode control.

A scoping review of rodent-borne pathogen presence, exposure, and transmission at zoological institutions

BACKGROUND

Rodents are one of the major taxa most likely to carry zoonotic diseases, harboring more than 85 unique zoonotic pathogens. While the significance of rodents' capacity to carry and transmit disease has been characterized in urban settings, the zoo environment is particularly unique given the overlap of collection, free-living, and feeder rodents as well as non-rodent collection animals, staff, and visitors.

ELIGIBILITY CRITERIA

This scoping review examines reports of rodent-borne pathogen detection or transmission in zoo settings extracted from the literature. Papers were included in the final analysis if there was evidence of presence or exposure to a pathogen in a rodent at a zoological institution.

SOURCES OF EVIDENCE

Publications were included from PubMed, CAB Abstracts and Biological Abstracts searched in August 2019.

CHARTING METHODS

Data extracted from publications on pathogen presence/exposure included publication identifiers, study identifiers, infectious agent identifiers, rodent identifiers, and non-rodent collection animal identifiers. Extraction from papers with evidence of disease transmission included number of rodents involved in transmission, non-rodent collection animal species and numbers, and job title of humans involved, diagnostic tests performed, and clinical outcomes.

RESULTS

Aggregate literature examined included 207 publications presenting evidence of pathogen presence and/or exposure in rodents across 43 countries in over 140 zoological institutions. A total of 143 infectious agent genera were identified, comprising 14 viral genera, 31 bacterial genera, 83 parasitic genera, and 15 fungal genera. Of these infectious agents, over 75 % were potentially zoonotic. The most common disease-causing agent genera identified were Leptospira, Toxoplasma, Salmonella, and Yersinia. Additional screening for evidence of pathogen transmission across species yielded 30 publications, indicating an area for future investigation to better inform surveillance and management priorities in order to reduce exposure, infection, and transmission.

CONCLUSIONS

Analyzing the breadth of rodent species and pathogens identified at zoos highlights the unique opportunity zoos have to be at the forefront of the early detection and identification of novel hosts and geographic ranges of rodent-borne pathogens with high impact on both endangered species and people. The overlap of these populations at zoos exemplifies the importance of considering One Health when prioritizing surveillance and risk mitigation of rodent reservoirs at zoos.

The treatment of sarcoptic mange in wildlife: a systematic review

BACKGROUND

Sarcoptic mange, caused by the Sarcoptes scabiei mite, is an infectious disease of wildlife, domestic animals and humans with international importance. Whilst a variety of treatment and control methods have been investigated in wildlife, the literature is fragmented and lacking consensus. The primary objectives of this review were to synthesise the diverse literature published on the treatment of sarcoptic mange in wildlife from around the world, and to identify the qualities of successful treatment strategies in both captive and free-roaming wildlife.

METHODS

A systematic search of the electronic databases CAB Direct, PubMed, Scopus, Web of Science, EMBASE and Discovery was undertaken. Data pertaining to study design, country, year, species, study size, mange severity, treatment protocol and outcomes were extracted from eligible studies and placed in a table. Following data extraction, a decision tree was used to identify studies suitable for further analysis based on the effectiveness of their treatment protocol, whether they were conducted on captive or non-captive wildlife, and the quality of their post-treatment monitoring period.

RESULTS

Twenty-eight studies met our initial inclusion criteria for data collection. Of these studies, 15 were selected for further analysis following application of the decision tree. This comprised of 9 studies on captive wildlife, 5 studies on free-living wildlife and 1 study involving both captive and free-living wildlife. Ivermectin delivered multiple times via subcutaneous injection at a dose between 200-400 µg/kg was found to be the most common and successfully used treatment, although long-term data on post-release survival and re-infection rates was elusive.

CONCLUSIONS

To our knowledge, this review is the first to demonstrate that multiple therapeutic protocols exist for the treatment of sarcoptic mange in wildlife. However, several contemporary treatment options are yet to be formally reported in wildlife, such as the use of isoxazoline chemicals as a one-off treatment. There is also a strong indication for more randomised controlled trials, as well as improved methods of post-treatment monitoring. Advancing this field of knowledge is expected to aid veterinarians, wildlife workers and policy makers with the design and implementation of effective treatment and management strategies for the conservation of wildlife affected by sarcoptic mange.