Biotic and abiotic factors influencing the prevalence, intensity and distribution of Eucoleus aerophilus and Crenosoma vulpis in red foxes, Vulpes vulpes from Romania

First Molecular Identification and Clinical Presentation of Crenosomosis in a Dog from Slovakia

PURPOSE

Crenosoma vulpis (Dujardin,1845) is a lungworm which has spread worldwide in canines and is associated with upper respiratory infections. In a majority of cases, the infections are accompanied with chronic cough. Diagnosis of lungworms is often underdiagnosed and can be misinterpreted as other respiratory diseases.

METHODS

The Small Animal Clinic of the University Veterinary Hospital admitted an 11-month-old dog presented with persistent cough associated with difficulty in breathing and even asphyxia. Based on clinical symptoms, the patient underwent radiological and bronchoscopic examination. Bronchoscopy revealed the presence of lungworms obturating the branches of the tracheobronchial tree. Larvae were collected by bronchoscopic lavage and subjected to parasitological and molecular examination.

RESULTS

Microscopic detection and morphological identification of the worms removed during the bronchoscopy confirmed the presence of female adult worms. The subsequent molecular characterisation of the mitochondrial (cytochrome c oxidase subunit I gene (cox1) and 12S ribosomal DNA (rDNA)), nuclear (18S rDNA) genes, as well as the analysis of the second internal transcribed spacer (ITS-2) region of the ribosomal DNA, confirmed the Crenosoma vulpis species. Faecal samples were processed using the Baermann method, which confirmed the presence of the larval stage 1 of C. vulpis. The therapy with fenbendazole at a dose of 50 mg/kg of live weight once daily for the period of 7 days was initiated for the patient.

CONCLUSION

This paper presents the first molecularly confirmed clinical case of a Crenosoma vulpis infection in an 11-month-old female dog of the Miniature Schnauzer breed in Slovakia.

Influence of environmental factors on the occurrence of gastrointestinal and cardiopulmonary nematodes in the red fox in the semi-arid Mediterranean areas of the Iberian Peninsula

Human-induced ecosystem fragmentation is one of the drivers causing wildlife migration from their natural habitats to urban areas, among other reasons. The red fox (Vulpes vulpes) is the most abundant wild canid in the semi-arid Mediterranean areas of the Iberian Peninsula. Water scarcity may result in areas shared by synanthropic fox populations and domestic animals becoming hotspots for parasite transmission. This study describes the gastrointestinal and cardiopulmonary nematode species affecting fox populations in these semi-arid areas and the influence of environmental variables on parasite abundance. A total of 167 foxes collected from 2015 to 2021 in the Region of Murcia (SE Spain) were analysed. Parasite abundance and spatial distribution were evaluated using environmental variables and host characteristics with a Generalised Linear Model and the Moran index. Eleven species (seven from the gastrointestinal tract and four from the cardiopulmonary tract) were described. The influence of biotic and abiotic variables was studied for Angiostrongylus vasorum, Crenosoma vulpis, Uncinaria stenocephala, Toxocara canis and Toxascaris leonina. Temperature, humidity and areas of forest or agricultural land influenced the abundance of these parasites, providing optimal conditions for free-living stages of the direct life cycle nematodes and intermediate hosts. Absolute abundance distribution maps showed defined locations for C. vulpis, T. canis and T. leonina. The results for U. stenocephala, T. canis and T. leonina were particularly important as their higher abundance levels were found close to anthropized areas, which need to be carefully evaluated to prevent transmission of these nematodes between domestic and wild canids and human health.

What is the sensitivity and exactness of post-mortem diagnostic method for cardiopulmonary nematodes in wild carnivores? towards the gold standard

Cardiopulmonary nematodes cause health and fitness disorders in wild and domestic carnivores. The red fox (Vulpes vulpes) participates in the spread of these shared parasites at the domestic-wildlife interface. This study aimed to evaluate the sensitivity of post-mortem diagnostic method for detecting lungworms in carnivores, and its exactness to estimate the parasite intensity of each nematode species. Cardiorespiratory system of fifty-one foxes were examined through three consecutively methodological steps: first, the tracheobronchial tree, pulmonary arteries and their branches were opened (OT); next, lung parenchyma was immersed in water and squeezed (WS); finally, the parenchyma was artificially digested in a pepsin and chlorhydric acid solution (AD). Eucoleus aerophilus, Angiostrongylus vasorum, Crenosoma vulpis and Metathelazia capsulata were identified. The number of recovered nematodes in each step were 454 (OT), 285 (WS) and 141 (AD). The use of OT and WS helped to improve parasite intensity results and decreased false negative cases. Accordingly, when OT and WS were used together, the sensitivity in the detection of parasitized foxes was 96.1%, while the exactness of parasite intensity was 84%. When AD was performed, although sensitivity does not rise, results were more exact, increasing the total number of detected parasites by 16%. Moreover, AD improved the sensitivity in the detection of A. vasorum and M. capsulata, as well as quantifying more exactly the parasite intensity (92.5% and 92.3% of exactness without AD, respectively). Our study provides valuable information that should be taken into account when planning epidemiological studies based on cardiopulmonary nematode detection in carnivores.

Occurrence of Eucoleus aerophilus in wild and domestic animals: a systematic review and meta-analysis

BACKGROUND

Eucoleus aerophilus (syn. Capillaria aerophila) is a nematode with a worldwide geographical distribution. It causes a disease called lung capillariosis by affecting the respiratory tract of wild and domestic animals, and has also occasionally been described in humans. Despite steady increases in knowledge of the morphology of this neglected parasite, many aspects are still poorly understood. Epidemiological data regarding, for example, geographic distribution, range of hosts, clinical relevance and the actual zoonotic potential of this nematode are scarce and incomplete.

METHODS

This article is a systematic review based on the screening of three databases (PubMed, Web of Science and Science Direct) to identify eligible studies published from 1973 to the end of 2022.

RESULTS

From a total of 606 studies describing the occurrence of E. aerophilus, 141 articles from 38 countries worldwide were included in this meta-analysis, all of which presented results obtained mainly with flotation and necropsy. Due to the occurrence of E. aerophilus in many different species and different matrices (lungs and faeces), we decided to conduct the meta-analysis separately for each species with a given matrix. This systematic review confirmed the status of the Red fox as the main reservoir and main transmitter of E. aerophilus (average prevalence of 43% in faeces and 49% in lungs) and provided evidence of a higher prevalence of E. aerophilus in wild animals in comparison to domestic animals, such as dogs (3% in faeces) and cats (2% in faeces and 8% in lungs). Previous studies have investigated many host-related factors (age, sex, environmental/living conditions) in relation to the prevalence of E. aerophilus, but they show wide variations and no simple relationship has been demonstrates. Furthermore, mixed infections with other pulmonary nematodes, such as Crenosoma vulpis and/or Angiostrongylus vasorum, are reported very frequently, which greatly complicates the diagnosis.

CONCLUSIONS

This systematic review focused on identifying data gaps and promoting future research directions in this area. To the best of our knowledge, this is the first systematic review that evaluates and summarizes existing knowledge on the occurrence and prevalence of E. aerophilus in wild and domestic animals originating from different geographical locations worldwide.

First report of Crenosoma vulpis in Africa and Eucoleus aerophilus in Algeria

Introduction

Crenosoma vulpis and Eucoleus aerophilus are widely distributed lungworms infecting carnivores, mainly red foxes, and are localized in the trachea, bronchi and bronchioles. There are no reports from Africa regarding the presence of C. vulpis. The aim of the present study was to report a co-infection with C. vulpis and E. aerophilus in a red fox from Algeria.

Materials and methods

In January 2022, a road-killed male juvenile red fox (Vulpes vulpes) was collected from Bouhadjar-Tarf locality and was submitted for a complete parasitological necropsy. Detected nematodes were collected and preserved in ethanol for morphological and molecular identification. Tissue samples were also collected and analyzed by histopathological methods.

Results

Collected nematodes were identified as a male C. vulpis and several Eucoleus aerophilus. The histological techniques of the lung tissue did not reveal the presence of any larvae, or lung inflammation.

Conclusion

To the best of our knowledge, this is the first report of C. vulpis infecting a carnivore in this continent, highlighting the importance of further studies to update the geographical distribution of C. vulpis. E. aerophilus was first reported in Algeria. Red foxes are important spreaders of parasitic diseases. Further studies are required for a better understanding of its epidemiology across North Africa and other areas overlapping the range of the red fox.

Predictive factors for flea occurrence in red foxes (Vulpes vulpes) from semi-arid Mediterranean environments

The role of red fox as host for a wide range of parasites, particularly fleas and other arthropods causing vector-borne diseases, in combination with its capability to adapt to anthropized environments, makes this wild canid an epidemiologically remarkable species at the wildlife-domestic-human interface, especially in the present time of rise of emerging and re-emerging diseases. This study evaluated the prevalence and parasite intensity of fleas in 88 foxes from Murcia Region (Southeastern Spain) and determined the geographic distribution of areas with the highest potential risk of flea presence. Pulex irritans, Ctenocephalides felis, Spilopsyllus cuniculi and Nosopsyllus fasciatus were identified. The overall prevalence was 76.13%. This is the first time that N. fasciatus has been reported in foxes from Murcia Region. The predictive model established a certain pattern to determine the areas with the highest risk of acquiring fleas. Positive correlation of daily potential evapotranspiration (ET₀ ) in winter and the opposite effect occurring for ET₀ in summer were obtained, as well as positive correlations for mean daily temperature (T_mean ) in summer and mean precipitation (P_mean ) in winter and summer. The model was also found positively correlated in the forest habitat ecotone areas and the anthropized areas.

Gastrointestinal parasites in wild rodents in Chiloé Island-Chile

Gastrointestinal parasites are well-documented in small mammals from north-central Chile, but little is known about endoparasites of rodents in southern Chile. A survey was conducted between January and February 2018 to evaluate gastrointestinal parasites and risk factors of wild rodents that live in rural areas in Northern Chiloé Island, Chile. A total of 174 fecal samples from rodents of six native and one introduced species were collected and examined using the Mini-FLOTAC method. Also, 41 individuals of four native wild rodent species were examined furtherly to determinate adult parasites from gastrointestinal tracts. The overall prevalence of endoparasites was 89.65% (156). Helminth egg types included: Rodentolepis spp., Capillariidae, Trichuris sp., Syphacia sp., oxyurid-type eggs, Strongyloides sp., Spirurid-type eggs, Strongilid-type eggs, Moniliformis sp., and an unidentified nematode egg and larvae. Protozoa comprised coccidia, amoeba, and unidentified cysts. From necropsies, adult parasites involved Syphacia sp. Trichuris sp., Protospirura sp. and Physaloptera sp. In Abrothrix olivacea, individuals with low-body-mass index exhibited reduced infection probability for Spirurid-type and Strongilid-type eggs. Some parasites in this study may affect human health. In rural settings where environmental conditions are changing, more research should be undertaken to understand parasitic infections in wildlife and implications for public health and conservation.

Diversity of Crenosoma species in mustelids with the first molecular characterization of C. melesi and C. petrowi

Species of genus Crenosoma have a wide distribution and are reported in Europe, the Americas, and Asia. Currently, the genus includes 14 nominal species, out of which 9 are parasitic in mustelids. Two species are mostly reported in mustelids from Europe, namely C. melesi and C. petrowi. Up to now, no genetic sequences are deposited in GenBank for any of the two. The aims of this study were to investigate the distribution, prevalence, and diversity of Crenosoma spp. infecting mustelids in Romania and to genetically characterize the species. Mustelids (n = 247) were collected over a period of 7 years from different locations in Romania and the respiratory tract was removed and examined for nematodes. Detected nematodes were morphologically identified and fragments of two genes were sequenced. Sampled mustelids included Eurasian badger, Meles meles (n = 102), Eurasian otter, Lutra lutra (n = 20), beech marten, Martes foina (n = 36), European pine marten, Martes martes (n = 5), steppe polecat, Mustela eversmanii (n = 1), European mink, Mustela lutreola (n = 1), least weasel, Mustela nivalis (n = 2), European polecat, Mustela putorius (n = 78), and marbled polecat, Vormela peregusna (n = 1). Nematodes from Eurasian badgers were morphologically identified as C. melesi (n = 13, 12.74%) and C. petrowi (n = 3, 2.94%). Nematodes from the beech martens were identified as C. petrowi (n = 6, 16.66%), C. vulpis (n = 1, 2.78%) and Crenosoma spp. (n = 3, 8.33%). Co-infections with two Crenosoma species were detected in one beech marten (C. petrowi + C. vulpis, n = 1, 2.77%) and in one European pine marten [C. petrowi + C. vulpis (n = 1, 20%)]. Two genes of Crenosoma melesi and C. petrowi were partly sequenced for the first time. We report new host-parasite associations for M. martes and C. vulpis. However, further studies are needed in order to determine the host-parasite associations and to improve the understanding of the epidemiology of Crenosoma nematodes.

Cardiorespiratory nematodes and co-infections with gastrointestinal parasites in new arrivals at dog and cat shelters in north-western Spain

Metastrongyloid and trichuroid cardiorespiratory nematodes of dogs and cats are considered emergent in several European countries, and an increase in the number and extent of endemic foci has been described. Since data on their prevalence are limited in this continent, faecal samples from new arrivals (365 dogs and 65 cats) at two animal shelters in North-western Spain were analysed using both floatation and Baermann techniques. In order to confirm the microscopic identification of Metastrongylidae first stage larvae, molecular characterization based on the sequence of the ITS-2 was performed. The possible influence of some variables such as the species, sex and age of the animals and the co-infection with other gastrointestinal parasites on the prevalence of cardiorespiratory nematodes was analysed. The most prevalent metastrongylid was Aelurostrongylus abstrusus (15.4%) followed by Angiostrongylus vasorum (4.1%) and Crenosoma vulpis (1.1%). Regarding trichuroids, Eucoleus aerophilus and/or Eucoleus boehmi eggs were detected in 28 dogs (7.7%) and four cats (6.2%). Almost all animals positive to cardiorespiratory nematodes (86.8%) were co-infected with gastrointestinal parasites. The prevalence of Metastrongylidae and respiratory trichuroids was significantly higher in dogs co-infected with Taenia spp. and Toxocara canis or Giardia duodenalis and Sarcocystis spp., respectively. In cats, a significant higher prevalence of Metastrongylidae nematodes was found in animals co-infected with Toxocara cati. Our results reveal that cardiorespiratory nematodes are common in companion animals from north-western Spain, showing higher prevalences than those previously reported from this country. This investigation represents the first report of C. vulpis, E. aerophilus and E. boehmi in dogs from Spain. The identification of a number of zoonotic parasites is of public health concern. Our results indicate that these nematodes should be included in the differential diagnosis of dogs and cats from north-western Spain showing respiratory or cardiac clinical signs.