Co-introduction into a delicate island ecosystem: metastrongyloid nematodes (superfamily Metastrongyloidea) of veterinary and medical importance circulating in aquatic and terrestrial environments of Tenerife (Canary Islands).

Metastrongyloid nematodes typically reside as adults in the cardiopulmonary systems of their mammalian definitive hosts, potentially causing severe diseases. Of particular concern are Angiostrongylus cantonensis and A. costaricensis, which can cause eosinophilic meningitis and abdominal angiostrongyliasis, respectively, in their accidental human hosts. Several metastrongyloid species of medical and veterinary importance have been documented in the Canary Islands. However, the gastropod species acting as intermediate hosts for some of these nematodes in the archipelago remained unknown. This study aimed to investigate the occurrence of metastrongyloid nematodes in terrestrial and aquatic gastropods, including both endemic and non-native species, on Tenerife. Foot samples from terrestrial and aquatic gastropods were analyzed using a multiplex PCR targeting the Internal Transcribed Spacer 1 (ITS1), allowing the specific detection of A. cantonensis, A. vasorum, Aelurostrongylus abstrusus, Crenosoma striatum, Troglostrongylus brevior, and Crenosoma vulpis. Five metastrongyloid species, namely C. striatum, A. cantonensis, Ae. abstrusus, A. vasorum, and an unidentified metastrongyloid, were identified within both non-native and endemic terrestrial gastropods. In the aquatic snail Physella acuta, only A. cantonensis and C. striatum were detected. This study confirms the introduction of various metastrongyloids associated with non-native mammalian fauna and provides new data on the occurrence of these nematodes in non-native and endemic gastropod species, including their presence in aquatic environments on the Canary Islands.

Angiostrongylus vasorum in golden jackals (Canis aureus) and red foxes (Vulpes vulpes) from Northern Bosnia and Herzegovina.

In this study, we conducted post-mortem examinations of golden jackals (Canis aureus) and red foxes (Vulpes vulpes) from the northern region of the Republic of Srpska (Bosnia and Herzegovina) to detect the presence of Angiostrongylus vasorum. An epidemiological survey was conducted in the densest golden jackal population in the country. Over two time intervals, we examined a total of 30 jackals and 16 foxes. The presence of A. vasorum was confirmed in two jackals (6.6%) and one fox (6.25%). These findings strongly suggest that the spread of A. vasorum can be facilitated by the active expansion and migration of golden jackals in Southeastern Europe. The morphological and molecular detection of A. vasorum in jackals and foxes confirmed its presence and active circulation in wildlife, while the phylogenetic analysis of the ITS-2 gene indicated a low sequence distance from European isolates.

First case of autochthonous Angiostrongylus vasorum infection in a Norwegian dog.

A fifteen-month-old Pembroke Welsh corgi with respiratory distress, exercise intolerance, and moderate regenerative anemia was referred to The Norwegian University of Life Sciences, Small Animal Hospital.Hematology revealed moderate regenerative anemia without evidence of hemolysis. Thoracic radiographs showed a generalized mixed interstitial to alveolar lung pattern and enlarged pulmonary arteries. Changes suggestive of moderate pulmonary hypertension were noted on echocardiography. Baermann fecal diagnostic flotation identified large numbers of Angiostrongylus vasorum larvae, and the AngioDetect serological antigen test was positive. The dog was treated with a two-week course with fenbendazole (51 mg/kg q24h po) and topical imidacloprid/moxidectin (250 mg/62.5 mg) and a one-week course with sildenafil (0.45 mg/kg q12h po). Complete clinical, clinicopathological and echocardiographic resolution was observed after only four weeks. Rapid improvement of echocardiographic abnormalities in cases with suspected pulmonary hypertension is not usually reported in cases with angiostrongylosis.Infection with A. vasorum should be considered in dogs with respiratory signs and bleeding tendencies, even in countries with no endemic history or reported cases.

Two cases of Angiostrongylus vasorum, a cardiopulmonary nematode, in a wild black bear and coyote of Tennessee.

Angiostrongylus vasorum, commonly known as the French heartworm, is a metastrongyloid parasitic nematode that infects wild and domestic canids. In North America, A. vasorum is endemic to the Canadian island of Newfoundland, but has been expanding to new areas including Nova Scotia, Prince Edward Island, and West Virginia (USA). Two cases of A. vasorum are reported from the state of Tennessee. The first case in a black bear (Ursus americanus) and the second case in a coyote (Canis latrans). The black bear was found dead in Sevier County in November of 2022, while the coyote was trapped and euthanized as part of a predator control program in Campbell County in January of 2023. Histology of the lungs revealed both animals had verminous pneumonia. DNA was extracted from the lungs of both, and PCR was performed using NC1 and NC2 primers. Sequencing results of the PCR products from the bear and coyote samples indicated that they were 95% and 96% similar, respectively, to European strains of A. vasorum. This report marks the first time A. vasorum has been reported in Tennessee as well as only the second and third report of autochthonous A. vasorum infection in the United States and the first report in an ursid. These two cases confirm the spread of A. vasorum further into North America. This nematode is highly pathogenic to wild and domestic canids, and thus these cases represent an emerging threat to both and underscore the need for further surveillance for the parasite.

First identification of Angiostrongylus spp. in Lissachatina fulica and Cornu aspersum in Antioquia, Colombia / Identificación de Angiostrongylus spp. en Lissachatina fulica y Cornu aspersum en Antioquia, Colombia

INTRODUCTION: Abdominal and neural angiostrongyliasis caused by Angiostrongylus costaricensis and A. cantonensis, respectively, are zoonotic diseases involving snails as intermediate hosts. Colombia has already reported human cases, and the increasing distribution of Lissachatina fulica and Cornu aspersum raises public health concerns due to the potential risk of disease transmission in areas where parasites and hosts coexist. OBJECTIVE: To identify the presence of Angiostrongylus spp. in snail species L. fulica and C. aspersum in Antioquia, Colombia. MATERIALS AND METHODS: This prospective cross-sectional study had a population of 5,855 L. fulica and C. aspersum snails captured in the ten towns of the Valle de Aburrá (Antioquia, Colombia), 169 samples were collected in 28 sampling points. Lung tissues of the collected snails were dissected and analyzed to detect Angiostrongylus spp. through molecular techniques. RESULTS: Angiostrongylus spp. were identified in both L. fulica and C. aspersum. Angiostrongylus costaricensis was detected in 18 pooled prevalence of 30% (95% CI = 19.2-43.3), and Medellín was the municipality with the highest number of positive samples (33.3%). Seventy-two-point-two percent of the positive places reported the presence of rodents. None of the tests were positive for A. cantonensis. CONCLUSION: Our findings provide important insights into the epidemiology and distribution of Angiostrongylus spp. in Antioquia, Colombia. The identification of these parasitic nematodes in L. fulica and C. aspersum highlights the potential role of these snails as intermediate hosts in the transmission of Angiostrongylus spp. infections in the Valle de Aburrá, with implications for human and veterinary health.

Introducción: La angiostrongiliasis abdominal y neura ­causadas por Angiostrongylus costaricensis y A. cantonensis, respectivamente­ son zoonosis que involucran caracoles como huéspedes intermediarios. Colombia ya ha reportado casos en humanos y la ampliación de la distribución de Lissachatina fulica y Cornu aspersum aumenta la preocupación en salud pública debido al riesgo potencial de transmisión en áreas donde los parásitos y sus huéspedes coexisten. Objetivo: Identificar la presencia de Angiostrongylus spp. en caracoles de las especies L. fulica y C. aspersum en Antioquia (Colombia). Materiales y métodos: Se llevó a cabo un estudio transversal prospectivo con una población de 5.855 caracoles de L. fulica o C. aspersum, capturados en diez ciudades del valle de Aburrá; 169 muestras fueron recolectadas en 28 puntos de muestreo. Se disecaron los tejidos pulmonares de los caracoles y se emplearon técnicas moleculares para detectar la presencia de Angiostrongylus spp. Resultados: Angiostrongylus costaricensis fue detectado en 18 muestras agrupadas (30 %; IC95%: 19,2-43,3), tanto en L. fulica como en C. aspersum. Medellín fue el municipio con el mayor número de muestras positivas (33,3 %). El 72,2 % de los lugares positivos reportaron la presencia de roedores. Ninguna de las pruebas fue positiva para A. cantonensis. Conclusión: Estos hallazgos brindan información importante sobre la distribución de Angiostrongylus spp. en Antioquia (Colombia). La identificación de estos nemátodos en L. fulica y C. aspersum resalta el papel potencial de estos caracoles como huéspedes intermediarios en la transmisión de infecciones por Angiostrongylus en el valle de Aburrá, con implicaciones para la salud humana y veterinaria.

Seek, and you will find: Cryptic diversity of the cardiopulmonary nematode Angiostrongylus vasorum in the Americas.

Angiostrongylus vasorum is a metastrongylid parasite infecting wild canids and domestic dogs. Its patchy distribution, high pathogenicity and taxonomical classification makes the evolutionary history of A. vasorum intriguing and important to study. First larval stages of A. vasorum were recovered from feces of two grey foxes, Urocyon cinereoargenteus, from Costa Rica. Sequencing and phylogenetic and haplotypic analyses of the ITS2, 18S and cytochrome oxidase subunit 1 (cox1) fragments were performed. Then p- and Nei´s genetic distance, nucleotide substitution rates and species delimitation analyses were conducted with cox1 data of the specimens collected herein and other Angiostrongylus spp. Cophylogenetic congruence and coevolutionary events of Angiostrongylus spp. and their hosts were evaluated using patristic and phenetic distances and maximum parsimony reconciliations. Specimens from Costa Rica clustered in a separate branch from European and Brazilian A. vasorum sequences in the phylogenetic and haplotype network analyses using the ITS2 and cox1 data. In addition, cox1 p-distance of the sequences derived from Costa Rica were up to 8.6 % different to the ones from Europe and Brazil, a finding mirrored in Nei´s genetic distance PCoA. Species delimitation analysis supported a separate group with the sequences from Costa Rica, suggesting that these worms may represent cryptic variants of A. vasorum, a new undescribed taxon or Angiocaulus raillieti, a synonym species of A. vasorum described in Brazil. Moreover, nucleotide substitution rates in A. vasorum were up to six times higher than in the congener Angiostrongylus cantonensis. This finding and the long time elapsed since the last common ancestor between both species may explain the larger diversity in A. vasorum. Finally, cophylogenetic congruence was observed between Angiostrongylus spp. and their hosts, with cospeciation events occurring at deeper taxonomic branching of host order. Altogether, our data suggest that the diversity of the genus Angiostrongylus is larger than expected, since additional species may be circulating in wild canids from the Americas.

First autochthonous case of Angiostrongylus vasorum in a domestic dog in the United States.

OBJECTIVE: To describe the clinical presentation, diagnostic findings, and medical management of the first suspected autochthonous case of a dog in the US diagnosed with Angiostrongylus vasorum, the French heartworm. ANIMAL: A 10-month-old Goldendoodle born in Oregon and residing in Washington State. CLINICAL PRESENTATION, PROGRESSION, AND PROCEDURES: The dog presented for evaluation of intermittent vomiting and diarrhea. Bloodwork revealed leukocytosis with mild lymphocytosis, monocytosis, eosinophilia, and basophilia. Larvae were detected on a fecal flotation, and fecal PCR confirmed A vasorum. TREATMENT AND OUTCOME: Administration of milbemycin oxime PO once a week for 4 weeks was initiated with recommendation to continue monthly treatment at label dose. The patient improved over the course of treatment. CLINICAL RELEVANCE: This case highlights the clinical and diagnostic findings and medical management of A vasorum, also known as the French heartworm, in a dog in the US. Few cases of A vasorum have been reported in wild foxes in North America, mostly in eastern Canada and 1 within the eastern US. Here we report for the first time an autochthonous case of A vasorum in a domestic dog in the US and the first report of any canid in the western US. This case highlights the importance of considering A vasorum as a differential for respiratory disease, gastrointestinal disease, or inexplicable eosinophilia in canine veterinary patients in the US and raises awareness for veterinary practitioners to incorporate appropriate preventative and diagnostic measures for their canine patients.

Clinical efficacy of a parasiticide formulation containing eprinomectin, esafoxolaner and praziquantel (NexGard® Combo) in the treatment of natural feline aelurostrongylosis and troglostrongylosis.

The metastrongyloids Aelurostrongylus abstrusus and Troglostrongylus brevior are primary causes of feline clinical respiratory disease. The present field trial evaluated the clinical efficacy of a spot-on formulation containing eprinomectin, esafoxolaner and praziquantel (NexGard® Combo) administered per label recommendations to cats affected with aelurostrongylosis and/or troglostrongylosis. Overall, 36 naturally infected cats were randomly assigned to Group 1 (G1) or Group 2 (G2) of 18 cats each. The two groups included 6 cats with A. abstrusus, T. brevior and mixed infection, each. All cats completed the study. Cats in G1 were treated on study Days (SDs) 0 and 28±2. Cats in G2 served as negative control until SD 56±2 and were then treated on SD 56±2 and 84±2. On SD 0/-7, 28±2 and SD 56±2 all cats were subjected to parasitological (quali-quantitative Baermann) and clinical examinations (physical exams and thoracic X-rays). Hematology and biochemistry analyses were performed on SD 0/-7 and SD 56±2. On SD 84±2 quali-quantitative Baermann, clinical examination and thorax radiography were performed on all G2 cats and on two G1 cats that still had radiographic alterations on SD 56±2. On SD 112±2 all G2 cats were subjected to parasitological and clinical evaluations and one cat from G1 that still had radiographic signs at SD 84±2 was clinically and radiographically evaluated. Efficacy criteria were the reduction of larval shedding in faeces and the clinical response in terms of pathological and radiographic scores after treatment compared to the baseline. An efficacy of 100 % based on LPG reduction was recorded after one (20/24 cats) or two (all 24 cats) treatments in cats with single infection by A. abstrusus or T. brevior. For cats with mixed infections, larval shedding was stopped after one (11/12 cats) or two (all 12 cats) treatments. Statistically significant clinical and radiographic improvement was evident in all study cats after 2 treatments. The present data show that two monthly treatments with NexGard® Combo stopped larval shedding and led to a significant clinical recovery and a complete resolution of radiographic abnormalities in cats infected with A. abstrusus and/or T. brevior.

Occurrence and identification of lungworms in Iranian wild boars.

This study represents the first investigation into the occurrence and identification of Metastrongylus spp. in wild boars (Sus scrofa) in Iran, utilizing both molecular and morphological methods. Thirteen wild boars from Kerman Province were examined, with 92.3% found to be infected with at least one species of Metastrongylus. Mixed infections were observed in 38.46% of the animals. Morphological and molecular analyses confirmed the presence of M. pudendotectus and M. salmi, with prevalence rates of 76.9% and 53.9%, respectively. Histopathological examination revealed transverse and longitudinal sections of Metastrongylus parasites within the airways, causing partial to complete obstruction, interstitial pneumonia, and inflammatory responses. The study also highlights the public health significance of these parasites. The higher prevalence observed compared to earlier studies suggests changes in environmental conditions, host dynamics, or agricultural practices as possible factors, warranting further investigation. The findings underscore the need for comprehensive surveillance and control measures to mitigate the risk of zoonotic transmission, particularly in regions with significant wild and domestic swine populations. This study contributes to the understanding of Metastrongylus spp. distribution and their pathological impact, emphasizing the ecological importance of wild boars and the necessity for continued monitoring and research to prevent and control infections in both animal and human populations.

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.

Early Detection and Management of Lamanema chavezi infection in a llama (Lama glama) in Switzerland.

Lamanema chavezi is an entero-hepatic strongylid parasite specific to South American camelids. It has been reported only on few occasions outside South America. Due to its hepatic migration, it can cause extensive liver damage, leading to granulomatous and fibrotic hepatitis and manifesting with lethargy, anorexia, and even death. We are reporting the second case of L. chavezi infection in Europe and the first in Switzerland. The patient was a three-year old neutered male llama (Lama glama). Clinical examination revealed bloody mucous discharge from the anus. Fecal sedimentation/flotation revealed strongylid eggs consistent with L. chavezi, which were molecularly confirmed by a PCR targeting the ITS2 plus 5.8S and 28S rDNA flanking regions and amplicon sequencing. Eighteen weeks after administration of a single dose of eprinomectin (0.2 mg/kg i.m.), no further L. chavezi eggs were detected in the feces. The source of infection could not be traced back. The entire herd consisted of llamas bred in Switzerland. L. chavezi has been rarely reported outside South America, but its potential for pathogenicity and establishment should not be underestimated. Fecal sedimentation/flotation techniques should be routinely performed to ensure early detection of the parasite.

Epidemiology of Angiostrongylus vasorum and Crenosoma vulpis infection in dogs in Denmark.

OBJECTIVES: This retrospective study aimed to evaluate the risk factors (age and breed group) associated with Angiostrongylus vasorum and Crenosoma vulpis infection in dogs. MATERIALS AND METHODS: Faecal examinations obtained in dogs from January 2016 to December 2021 as part of routine clinical practice at two veterinary clinics in the Odsherred region of Zealand, Denmark, were included in this study. Faecal samples were analysed using the Baermann technique for nematode detection. Samples were collected from two clinics located in Northwestern Zealand, Denmark. Multinomial regression analysis, quasi-Poisson models and a generalised additive model for linearity were used to analyse the data. RESULTS: A total of 2,013 faecal samples were included in the study. Age was a significant risk factor for a positive Baermann, with a negative linear relationship observed (A. vasorum odds ratio: 0.80, 95% confidence interval: 0.70 to 0.91, C. vulpis odds ratio: 0.95, 95% confidence interval: 0.91 to 0.99, both nematodes: odds ratio: 0.87, 95% confidence interval: 0.77 to 0.99). Breed group analysis considering retrievers and flushing and water dog as reference group, demonstrated that sheep- and cattle dogs had a reduced risk of C. vulpis infection (odds ratio: 0.49, 95% confidence interval: 0.24 to 0.97), whereas dachshunds had an increased risk of A. vasorum infection (odds ratio: 3.28, 95% confidence interval: 1.14 to 9.47). Variations in the number of nematodes was found, with companion and toy dogs exhibiting higher numbers of C. vulpis (incidence rate ratio: 21.40, 95% confidence interval: 2.88 to 159) and sheep- and cattle dogs displaying higher numbers of A. vasorum (incidence rate ratio: 30.20, 95% confidence interval: 7.33 to 125). The prevalence rates of C. vulpis and A. vasorum were estimated at 14.50% (95% confidence interval: 13 to 16.10) and 3.40% (95% confidence interval: 2.70 to 4.30), respectively. CLINICAL SIGNIFICANCE: There are significant risk factors for nematode infection in dogs that can be considered for proper preventive care of this condition.

[Experimental study on the artificial infection of common freshwater snails with Angiostrongylus cantonensis in Dali Bai Autonomous Prefecture, Yunnan Province].

OBJECTIVE: To evaluate the potential risk of transmission of angiostrongyliasis by common freshwater snails in Dali Bai Autonomous Prefecture, Yunnan Province, so as to provide insights into local surveillance of angiostrongyliasis. METHODS: Common freshwater snails were collected from Dali Bai Autonomous Prefecture, Yunnan Province from March to April, 2020, and identified and bred in laboratory. SD rats were infected with third-stage larvae of Angiostrongylus cantonensis that were isolated from commercially available Pomacea canaliculata snails in Dali Bai Autonomous Prefecture, and freshwater snails were infected with the first-stage larvae of A. cantonensis that were isolated from the feces of SD rats 39 days post-infection at room temperature. The developmental process and morphological characteristics of worms in hosts were observed, and the percentages of A. cantonensis infections in different species of freshwater snails were calculated. Then, SD rats were infected with the third-stage larvae of A. cantonensis that were isolated from A. cantonensis-infected freshwater snails, and the larval development and reproduction was observed. RESULTS: More than 3 000 freshwater snail samples were collected from farmlands, ditches and wetlands around Erhai Lake in Dali Bai Autonomous Prefecture, and Cipangopaludina chinensis, P. canaliculata, Parafossarulus striatulus, Oncomelania hupensis robertsoni, Galba pervia, Physa acuta, Radix swinhoei, Assiminea spp., Tricula spp. and Bellamya spp. were morphologically identified. A total of 105 commercially available P. canaliculata snails were tested for A. cantonensis infections, and 2 P. canaliculata snails were found to be infected with A. cantonensis, in which the third-stage larvae of A. cantonensis were isolated. Ten species of freshwater snails were artificially infected with the third-stage larvae of A. cantonensis, and all 10 species of freshwater snails were found to be infected with A. cantonensis, with the highest positive rate of A. cantonensis infections in Bellamya spp. (62.3%, 137/204), and the lowest in C. chinensis (35.5%, 11/31). After SD rats were infected with the third-stage larvae of A. cantonensis isolated from different species of freshwater snails, mature adult worms of A. cantonensis were yielded. CONCLUSIONS: Multiple species of freshwater snails may serve as intermediate hosts of A. cantonensis under laboratory conditions in Dali Bai Autonomous Prefecture of Yunnan Province. Further investigations on natural infection of A. cantonensis in wild snails in Dali Bai Autonomous Prefecture seem justified.

A new diagnostic technique for identifying Angiostrongylus spp. larvae in intermediate snail species by examining the buccal cavity.

BACKGROUND: Angiostrongyliasis is a zoonotic parasitic disease caused by the rat lungworm Angiostrongylus cantonensis. The intermediate hosts of A. cantonensis are gastropods, and snail species such as Pomacea canaliculata play a key role in the transmission of human angiostrongyliasis. Detecting A. cantonensis infection in snails is an important component of epidemiological surveillance and the control of angiostrongyliasis. METHODS: In this study, a new method for diagnosing A. cantonensis infection in gastropods was developed by recovering larvae from the buccal cavity of three snail species. The entire buccal cavity of a snail was extracted, and the tissue was pressed between two microscope slides to observe whether A. cantonensis larvae were present. Our new method was compared with traditional pathogenic detection methods of lung microscopy, tissue homogenization, and artificial digestion. We artificially infected 160 P. canaliculata, 160 Cipangopaludina chinensis, and 160 Bellamya aeruginosa snails with A. cantonensis. Then, the four different detection methods were used to diagnose infection in each snail species at 7, 14, 21, and 28 days post exposure. RESULTS: We found no significant difference in the percentages of infected P. canaliculata snails using the four methods to detect A. cantonensis larvae. The radula pressing method had a mean detection rate of 80%, while the lung microscopy (81.3%), tissue homogenization (83.8%), and artificial digestion (85%) methods had slightly greater detection rates. Similarly, the percentages of infected C. chinensis snails that were detected using the radula pressing (80%), tissue homogenization (82.1%), and artificial digestion (83.8%) methods were not significantly different. Finally, the percentages of infected B. aeruginosa snails that were detected using the radula pressing (81.3%), tissue homogenization (81.9%), and artificial digestion (81.4%) methods were not significantly different. These results showed that the radula pressing method had a similar detection rate to traditional lung microscopy, tissue homogenization, or artificial digestion methods. CONCLUSIONS: This study demonstrates a new method for the qualitative screening of gastropods that act as intermediate hosts of A. cantonensis (and other Angiostrongylus species), provides technical support for the control of human angiostrongyliasis, and furthers research on A. cantonensis.

Reaching new lands: Updating the distribution of Angiostrongylus cantonensis in South America with the first record in Argentina.

BACKGROUND: Angiostrongylus cantonensis, commonly known as the rat lungworm, is a metastrongyloid nematode found primarily not only in tropical and subtropical regions but also in temperate areas and considered the leading cause of eosinophilic meningitis in humans. Synanthropic rodents such as Rattus norvegicus and Rattus rattus are the most frequent definitive hosts of this parasite. METHODS AND RESULTS: The presence of this parasite was detected in the pulmonary arteries of three specimens of R. norvegicus in the city of Buenos Aires representing the species' southernmost known record in natural hosts. Species confirmation was achieved through partial sequences of 18S and COI genes. By comparing the COI gene sequences with those available in GenBank through the construction of a haplotype network, we obtained that the analysed specimen presents high similarity with those reported in Japan and Southeast Asia. CONCLUSIONS: All infected rats were captured in an area surrounding a port with significant import and export activity, suggesting that A. cantonensis may have been introduced through commercial ships. Specifically, the parasite was detected in a neighbourhood with vulnerable socio-economic conditions and in a nature reserve, which exhibit biotic and abiotic characteristics conducive to sustaining high-density rat populations, scattered waste, areas of spontaneous vegetation, debris accumulation and flooded areas or lagoons offering suitable habitats for intermediate hosts such as snails. Thus, the close proximity of the port to these sites creates a favourable ecological context for the establishment of A. cantonensis. This study shows the need to conduct research to detect A. cantonensis in non-endemic areas but with the characteristics that promote its arrival and development of its life cycle in order to implement control measures to prevent expansion of this parasite and its transmission to humans and other animals.

Detection of rat lungworm (Angiostrongylus cantonensis) infection by real-time PCR from the peripheral blood of animals: a preliminary study.

Rat lungworm disease or neuroangiostrongyliasis is a cerebral parasitic infection that affects humans and animals alike. Its clinical signs and symptoms can range from mild self-resolving to serious life-threatening conditions. Studies suggest therapeutic interventions during the early stages of infection to be more effective than in later stages. However, early diagnosis of infection is usually problematic without the knowledge of exposure and/or detection of the parasite's DNA or antibody against the parasite in the cerebrospinal fluid. This requires a lumbar puncture, which is an invasive procedure that generally requires hospitalization. This study evaluates an affordable and less invasive alternative to detect parasitic DNA by PCR from the peripheral blood of potentially infected animals. Blood samples from 58 animals (55 dogs and 3 cats) with clinical suspicion of infection were submitted to our lab between February 2019 and August 2022 by local, licensed veterinarians. DNA was extracted from whole blood, plasma, serum, and/or packed cells using the Qiagen DNeasy Blood & Tissue Kit as per the manufacturer's protocol. All 58 animals were tested by real-time PCR using the AcanITS1 assay and 32 of these animals (31dogs; 1 cat) were also tested using the AcanR3990 assay. The PCR results for both assays were classified into strongly positive > positive > weakly positive > negative, and equivocal for ambiguous results, based on the strength of the signal. The percent infection detected using the AcanITS1 and AcanR3990 assays was 12.72% (7/55) and 20.68% (6/29), respectively. The overall percent infection detected was 34.37% (11/32), with only two animals testing positive by both assays. The three cats involved in this study tested negative by both assays. These results are promising and warrant further investigations to increase sensitivity including variables that might affect detection in the blood, such as parasite load, and laboratory methodologies.

Occurrence of Stenurus globicephalae (Nematoda: Pseudaliidae) in the blowhole of Globicephala macrorhynchus (Cetacea: Delphinidae) in Tasmania, Australia.

Information about parasites of cetaceans in Australia is scarce and mostly opportunistic. The morphology of specimens of the metastrongyloid Stenurus globicephalae Baylis & Daubney, 1925 (Nematoda: Pseudaliidae), collected from the blowhole of a pilot whale Globicephala macrorhynchus Gray, 1846 (Cetacea: Delphinidae) off northern Tasmania, Australia, were studied. Light and scanning electron microscopical examinations enabled a detailed redescription of this nematode species, including corrections of some inaccuracies in previous species descriptions, particularly those concerning cephalic and caudal structures. The presence of numerous ventrolateral oblique muscle bands, characteristic of the males of S. globicephalae, is reported for the first time. This is the second finding of this nematode parasite, in a different host species, in Tasmania.

In vitro and in vivo anthelmintic effect of essential oil obtained from Thymus capitatus flowers against Haemonchus contortus and Heligmosomoides polygyrus.

Sheep haemonchosis is a disease that causes serious losses in livestock production, particularly with the increase of cases of anthelmintic resistance around the world. This justifies the urgent need of alternative solutions. The aim of this study was to determine the chemical profile, in vitro, and, in vivo, anthelmintic properties of Thymus capitatus essential oil. To evaluate the, in vitro, anthelmintic activity of the T. capitatus EO on Haemonchus contortus, two tests were used: egg hatch assay (EHA) and adult worm motility (AWM) assay. The nematicidal effect of this oil was evaluated, in vivo, in mice infected artificially with Heligmosomoides polygyrus using faecal egg count reduction (FECR) and total worm count reduction (TWCR). Chromatographic characterization of T.capitatus composition using gas chromatography coupled to mass spectrometry (GC-MS) demonstrated the presence of carvacrol (81.16%), as the major constituents. The IC50 values obtained was 1.9 mg/mL in the EHT. In the AWM assay; T. capitatus essential oil achieved 70.8% inhibition at 1 mg/mL after 8 h incubation. The in vivo, evaluation on H. polygyrus revealed a significant nematicidal effect 7 days post-treatment by inducing 49.5% FECR and 64.5% TWCR, using the highest dose (1600 mg/kg). The results of present study, demonstrate that T.capitatus EO possess a significant anthelmintic properties. Furthermore, it could be an alternative source of anthelmintic agents against gastrointestinal infections caused by H. contortus.

Strongylids of Domestic Horses in Eastern Slovakia: Species Diversity and Evaluation of Particular Factors Affecting Strongylid Communities.

PURPOSE: This study aimed to examine the species diversity and structure of the strongylid community in domestic horses in Eastern Slovakia. Also, an analysis of the impact of age, sex, and collection location factors on the strongyid communities was performed. METHODS: Twenty-seven horses 1.5-21 years old from two farms in eastern Slovakia with different horse-management conditions were studied. Strongylids were collected after horse treatments with Noromectin (0.2 mg ivermectin); 66,170 specimens were collected and identified. Faecal egg count reduction test (FECRT) was performed following fenbendazole (FBZ) and ivermectin (IVM) treatments. RESULTS: Twenty-four strongylid species were found; horses were infected with 6 to 16 (average = 11.7) species. Six cyathostomin species (Cylicocyclus nassatus, Cyathostomum catinatum, C. pateratum, Cylicostephanus longibursatus, C. goldi, C. calicatus) were the most prevalent; C. catinatum was the dominant species in both farms (Berger-Parker index 0.34 and 0.42). The structure of the strongylid community was multimodal with dominant, subdominant, background, and rare species. The Mantel test showed that horse age and sex did not significantly affect the nematode infracommunity composition (p > 0.05), while the impact of the collection location (farm) was significant (p = 0.03). Additionally, C. longibursatus was identified as the species contributing significantly to the observed farm differences. Strong resistance to FBZ was documented on both farms (FECRT was 36.4% and 22.7%); IVM resistance was not observed (FECRT = 100%). CONCLUSION: This study presents the first report on the strongylids parasitizing domestic horses in Eastern Slovakia and gives basic information for further studies of horse parasites and their control in the region.

Nemabiome metabarcoding shows a high prevalence of Haemonchus contortus and predominance of Camelostrongylus mentulatus in alpaca herds in the northern UK.

Gastrointestinal nematodes (GINs) are a common threat faced by pastoral livestock. Since their major introduction to the UK in the early 1990s, South American camelids have been cograzed with sheep, horses, and other livestock, allowing exposure to a range of GIN species. However, there have been no molecular-based studies to investigate the GIN populations present in these camelids. In the current study, we sampled nine alpaca herds from northern England and southern Scotland and used high-throughput metabarcoded sequencing to describe their GIN species composition. A total of 71 amplicon sequence variants (ASVs) were identified representing eight known GIN species. Haemonchus contortus was the most prevalent species found in almost all herds in significant proportions. The identification of H. contortus in other livestock species is unusual in the northern UK, implying that alpacas may be suitable hosts and potential reservoirs for infection in other hosts. In addition, the camelid-adapted GIN species Camelostrongylus mentulatus was identified predominantly in herds with higher faecal egg counts. These findings highlight the value of applying advanced molecular methods, such as nemabiome metabarcoding to describe the dynamics of gastrointestinal nematode infections in novel situations. The results provide a strong base for further studies involving cograzing animals to confirm the potential role of alpacas in transmitting GIN species between hosts.