Use of a commercial serologic test for Angiostrongylus vasorum for the detection of A. chabaudi in wildcats and A. daskalovi in badgers

Wildlife parasitology: sample collection and processing, diagnostic constraints, and methodological challenges in terrestrial carnivores

Wild terrestrial carnivores play a crucial role as reservoir, maintenance, and spillover hosts for a wide parasite variety. They may harbor, shed, and transmit zoonotic parasites and parasites of veterinary importance for domestic hosts. Although wild carnivores are globally distributed and comprise many different species, some living in close proximity to human settlements, only a few studies have investigated parasites of wild terrestrial carnivores using non-specific techniques. Access to samples of wild carnivores may be challenging as some species are protected, and others are secretive, possibly explaining the data paucity. Considering the importance of wild carnivores' health and ecological role, combined with the lack of specific diagnostic methodologies, this review aims to offer an overview of the diagnostic methods for parasite investigation in wild terrestrial carnivores, providing the precise techniques for collection and analysis of fecal, blood, and tissue samples, the environmental impact on said samples, and the limitations researchers currently face in analyzing samples of wild terrestrial carnivores. In addition, this paper offers some crucial information on how different environmental factors affect parasite detection postmortem and how insects can be used to estimate the time of death with a specific highlight on insect larvae. The paper contains a literature review of available procedures and emphasizes the need for diagnostic method standardization in wild terrestrial carnivores.

A One-Year Retrospective Analysis of Viral and Parasitological Agents in Wildlife Animals Admitted to a First Aid Hospital

This study aimed to provide information on the presence and frequency of viral and parasitic agents in wildlife presented to a Veterinary Teaching Hospital in 2020-2021. Serum and faecal samples were collected from 50 rescued animals (roe deer, fallow deer, foxes, badgers, pine martens, and porcupines) and examined by serological, molecular, and parasitological techniques. Transtracheal wash (TTW) was also collected post-mortem from roe deer. Overall, the results of the different techniques showed infections with the following viral and parasitic agents: Bovine Viral Diarrhea Virus, Small Ruminant Lentiviruses, Kobuvirus, Astrovirus, Canine Adenovirus 1, Bopivirus, gastrointestinal strongyles, Capillaria, Ancylostomatidae, Toxocara canis, Trichuris vulpis, Hymenolepis, Strongyloides, Eimeria, Isospora, Dictyocaulus, Angiostrongylus vasorum, Crenosoma, Dirofilaria immitis, Neospora caninum, Giardia duodenalis, and Cryptosporidium. Sequencing (Tpi locus) identified G. duodenalis sub-assemblages AI and BIV in one roe deer and one porcupine, respectively. Adult lungworms collected from the TTW were identified as Dictyocaulus capreolus (COX1 gene). This is the first molecular identification of G. duodenalis sub-assemblage AI and D. capreolus in roe deer in Italy. These results show a wide presence of pathogens in wild populations and provide an overview of environmental health surveillance.

Intra Vitam Diagnosis of Neglected Gurltia paralysans Infections in Domestic Cats (Felis catus) by a Commercial Serology Test for Canine Angiostrongylosis and Insights into Clinical and Histopathological Findings-Four-Case Report

Gurltia paralysans is a metastrongyloid nematode which belongs to the Angiostrongylidae family and presents tropism for veins of the subarachnoid space in vivo of domestic and wild felids causing a progressive and chronic clinical manifestation of paraparesis/paraplegia. The geographic distribution of G. paralysans includes rural and periurban areas of South America and was recently reported in Europe. To date, a definitive diagnosis of feline gurltiosis is still conducted by post-mortem examination of the spinal cord in affected animals. A presumptive diagnosis of feline gurltiosis can also be achieved based on data of compatible clinical signs and associated epidemiological risk factors. The aim of this preliminary study was to evaluate the commercial serological test Angio Detect TM^® (IDEXX Laboratories) as a possible diagnostic method of feline gurltiosis in vivo. For the study, 10 domestic felines (Felis catus) which originated from a high endemic area of Southern Chile, were analyzed. All felines presented chronic paraparesis or severe paraplegia. Subsequently, commercial Angio Detect TM^® serological tests for the detection of closely related Angiostrongylus vasorum in canids were performed according to manufacturer’s instructions. Conducted serological tests were positive in seven of ten felines showing paraplegia/paraparesis and presumably infected with G. paralysans, and four of them were additionally necropsied, and presented macroscopic findings compatible with feline gurltiosis. Furthermore, the presence of adult female and male G. paralysans specimens at the level of the subarachnoid vasculature in affected spinal cord segments were observed during necropsy. Histopathology demonstrated severe eosinophilic meningomyelitis, coagulopathies with thrombosis in G. paralysans-parasitized leptomeningeal veins. Results of this preliminary study suggest a cross-reaction between A. vasorum-specific antigens, which also parasitize blood vessels in vivo, and G. paralysans when using an Angio Detect TM^® test, which suggests its helpful use as a new diagnostic method for feline gurltiosis in live domestic felines. Additional specific antigen research will be required in order to better understand the sensitivity and specificity of A. vasorum antigens used in this test and for existing cross-reactivity with G. paralysans-derived antigens for future a suitable intra vitam immunodiagnosis of neglected feline gurltiosis.

Is Angiostrongylosis a Realistic Threat for Domestic Cats?

Three species of Angiostrongylus have been found in felids thus far, i.e., Angiostrongylus chabaudi, Angiostrongylus felineus and Angiostrongylus vasorum. Angiostrongylus chabaudi lives in the right heart and pulmonary arteries of the definitive natural host, the European wildcat (Felis silvestris), and non-patent infections have been reported in domestic cats (Felis catus). Angiostrongylus felineus, described in the Puma yaguarondi (Herpailurus yagouaroundi), has never been reported in domestic felids, while recently a non-patent infection by A. vasorum was unequivocally described in a F. catus. Nonetheless, epizootiological and clinical relevance of angiostrongylosis in domestic cats are practically unknown. This study investigated whether cases of angiostrongylosis may be missed in cats living in areas enzootic for Angiostrongylus spp. and other metastrongyloids. Overall, 100 cats that were either positive (n.50) or negative (n.50) for metastrongyloid larvae at the Baermann's test, were examined for Angiostrongylus spp. with DNA-based methods and with the serological test Angio Detect™ for circulating antigen. The PCR analysis confirmed the copromicroscopy results, where 25 cats scored positive for Aelurostrongylus abstrusus, 16 for Troglostrongylus brevior and 9 for both, while no cats were positive for Angiostrongylus-like larvae, including A. chabaudi. None of the 100 sera samples scored positive at the Angio Detect™ test. These data suggest that currently feline angiostrongylosis is a minor parasitosis for domestic cats. Nevertheless, it cannot be excluded that the epizootiological drivers which have favored the spillover of A. vasorum and T. brevior from wildlife to dogs and cats, could promote the emergence of feline angiostrongylosis, with an unpredictable health impact.

Molecular Survey of Metastrongyloid Lungworms in Domestic Cats (Felis silvestris catus) from Romania: A Retrospective Study (2008-2011)

Background: Lungworms are recognized as important agents in the pathology of the respiratory system in domestic cats. While Aelurostrongylus abstrusus is worldwide known and studied, Troglostrongylus brevior has gained the attention of the scientific community only in the last decade. The pathogenicity of this species seems to be higher than A. abstrusus, causing more severe clinical presentations and being potentially fatal, especially in young animals. Methods: In this study, 371 DNA isolates of faecal samples were tested by multiplex polymerase chain reaction for the presence of A. abstrusus, T. brevior, and Angiostrongylus chabaudi. Results: The results showed that 30.2% and 6.7% of the investigated domestic cats were positive for A. abstrusus and T. brevior respectively, stressing out the importance of these parasites as agents of respiratory conditions in domestic cats from Romania. None of the samples were positive for A. chabaudi. The age, the outdoor access, and the lack of deworming were identified as significant risk factors for infection with A. abstrusus. Conclusions: This paper represents the first report of T. brevior in domestic cats from Romania. Moreover, it presents the most northern localization in Europe of T. brevior.

First case of a natural infection in a domestic cat (Felis catus) with the canid heart worm Angiostrongylus vasorum

Cardiopulmonary nematodes in cats include different parasite species affecting feline lungs and the heart, with the metastrongyloid Aelurostrongylus abstrusus being the most frequent feline lungworm worldwide. The present case report describes an 11-month-old male neutered European short hair cat which presented with generalised subcutaneous oedema and pleural and peritoneal effusions. According to clinical examination, abdominal imaging and laboratory analyses, a tentative diagnosis of severe glomerulopathy with massive proteinuria was made. Due to worsening of the clinical signs despite therapeutic interventions and a poor prognosis, the cat was euthanised. Necropsy and histological examinations revealed severe bilateral collagenofibrotic glomerulopathy, generalised oedema and a focal verminous pneumonia with thrombosis in arterial lung vessels containing nematode cross sections. A serum sample was tested for the presence of antibodies against the cat lungworm A. abstrusus, resulting negative. Genetic analyses confirmed the presence of nematode DNA; after exclusion of common lung and heart parasites occurring in cats, DNA of the canid heart worm nematode Angiostrongylus vasorum was identified. This is the first description of a naturally occurring infection with A. vasorum in a cat. Previous experimental studies demonstrated the development of adult male and female A. vasorum worms containing eggs in cats, but no larval excretion in the faeces. Although cats did not become patent, A. vasorum infections were clinically relevant. As A. abstrusus and A. vasorum are both gastropod transmitted nematodes, they may share the same intermediate hosts within overlapping areas. In addition, especially chronic A. abstrusus infected cats become non-patent and do not excrete L1. Considering that patent A. vasorum infections are widespread in the dog and fox population in Switzerland (and several other countries) but are apparently not patent in cats, we cannot exclude that infections with A. vasorum may occur more frequently than expected.

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Angiostrongylus vasorum is a cardiopulmonary nematode of dogs and other canids

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First natural infection of a cat (Felis catus) with Angiostrongylus vasorum

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Histological nematode sections identified in pulmonary arteries, confirmed by PCR

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Aberrant, non-patent infection in the cat with clinical relevance

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Such infections may occur more frequently particularly in highly endemic areas

Larval development of Angiostrongylus chabaudi, the causative agent of feline angiostrongylosis, in the snail Cornu aspersum

Nematodes of the Angiostrongylidae family, such as Angiostrongylus vasorum and Angiostrongylus cantonensis, may cause potentially life-threatening diseases in several mammal species. Alongside these well-known species, Angiostrongylus chabaudi has been recently found affecting the cardiopulmonary system of domestic and wild cats from Italy, Germany, Greece, Romania and Bulgaria. Nonetheless, significant gaps in the understanding of A. chabaudi epidemiology include the lack of information of species acting as intermediate host and of the morphological description of larval stages. Cornu aspersum (n = 30) land snails were infected with 100 first-stage larvae of A. chabaudi collected from a naturally infected wildcat in Romania. Larvae at different developmental stages were found in 29 out of 30 (96·7%) infected snails and a total of 282 (mean 9·8 ± 3·02 larvae per each specimen) were collected from the gastropods. Here we demonstrate that A. chabaudi develops in snails and report C. aspersum as potential intermediate host for this parasitic nematode. Findings of this study are central to understand the ecological features of feline angiostrongylosis and its epidemiology within paratenic and intermediate hosts.