Occurrence of tongue worm, Linguatula cf. serrata (Pentastomida: Linguatulidae) in wild canids and livestock in south-eastern Australia

First findings of Sarcocystis species in game deer and feral pigs in Australia

Several wild game meat species, including deer and feral pigs are hunted and consumed in Australia. Feral pigs and deer are not indigenous to Australia, but they have proliferated extensively and established their presence in every state and territory. Following the report of a sambar deer displaying Sarcocystis like white cysts in its rump muscles, the present study was conducted to explore the prevalence of Sarcocystis infections in wild deer and feral pigs in the southeastern regions of Australia. Oesophagus, diaphragm, and heart tissue from 90 deer and eight feral pigs were examined visually for sarcocysts. All results were negative. PCR testing of randomly selected deer and feral pigs yielded positive results, which were subsequently supported by histopathology. This is the first study to report the presence of Sarcocystis spp. in deer and feral pigs in Australia. As no visual cysts were found on the heart or oesophagus that came back positive with PCR, infected animals, particularly those reared free-range, could be passing through meat quality checks unidentified. If people consume this meat without cooking it properly, it may lead to a human infection of Sarcocystis. However, a more targeted study focused on determining the parasite's prevalence and assessing its risks is necessary to determine if it constitutes a food safety issue. As this species has been found not only in feral pigs but also in domestic pigs, the potential for infection spreading between feral pigs and pigs in free-range livestock systems is high, potentially posing a large problem for the Australian pork industry, particularly with the increased emphasis on free-range pig husbandry. Future studies should concentrate on determining the species of Sarcocystis in feral animals commonly consumed as game meat to determine potential zoonotic risks. This could also include a more in-depth look at the prevalence of Sarcocystis infections in other game animals. Identifying where these parasites are present and to what extent, are important areas for future studies.

Parasitosis in Pet Dogs from Rondônia, Amazon Biome, and Human Perception of Zoonoses

Zoonotic parasitic diseases in dogs are particularly concerning in regions with low human development indices due to inadequate sanitary services and insufficient environmental and health education. This study aimed to assess the parasitological status of dogs living in households and evaluate their owners' knowledge about zoonoses. A total of 183 dogs from Rolim de Moura, Rondônia State, were screened for the presence of ectoparasites, and 163 fecal samples were collected for analysis. The results showed that 74.23% (112/163) of the animals had at least one species of endoparasite. The most identified pathogens were Ancylostoma spp. (68.71%, 112/163), Trichuris vulpis (11.66%, 19/163), Toxocara canis (6.75%, 11/163), Cystoisospora canis (4.91%, 8/163), Dipylidium caninum (1.23%, 2/163), and Hammondia/Neospora (0.61%, 1/163). Ectoparasites were observed in 43.17% (79/183) of the evaluated animals, with Rhipicephalus sanguineus found in 31.15% (57/183) and Ctenocephalides felis felis in 20.77% (38/183). Only 11.48% (7/61) of the owners were familiar with the term "Zoonoses." However, a significant majority (83.61%, 51/61) believed that dogs can transmit diseases to humans. Our findings highlight the prevalence of parasites in the studied area and associated risk factors, underscoring the urgent need for educational interventions to raise awareness about these diseases and their risks to human health.

Characterization of the Tongue Worm, Linguatula serrata (Pentastomida), Identified from Hares (Lepus europaeus) in Romania

Linguatula serrata (Frölich, 1789) is a widespread parasite known as the tongue worm belonging to the family Linguatulidae. The adult form of the parasite is usually located in the upper respiratory tract of domestic and wild carnivores while the larval forms are located in the visceral organs of intermediate hosts (various herbivorous mammals). Twenty-four European brown hares (Lepus europaeus) were examined in this study, of which two were positive with L. serrata nymphs. The collected nymphs were examined morphologically using electron-microscopic analysis and molecularly by amplification of 18S rRNA and COX1 genes. Lung tissue samples were also collected and histopathological examination was performed. Histopathological examination revealed the following lesions: generalized inflammatory oedema, granulomas with necrosis, calcification and fibrosis in the bronchial tree. The results of molecular sequencing for L. serrata specimens collected from the European brown hares are deposited in GenBank. This study presents the first report on Linguatula serrata nymphs collected from L. europaeus in Romania, using molecular and morphological characterization simultaneously.

Linguatula serrata (Pentastomida: Linguatulidae) infection in a paucisymptomatic greyhound imported from Romania to Italy: A case report and literature overview

Background

Linguatula serrata is a pentastomid zoonotic parasite with worldwide distribution. Although some cases of L. serrata infection have been reported in dogs, the epidemiology of this parasite remains largely unknown in developed countries. In recent years, canine linguatulosis has been repeatedly linked to cases of imported infections. This study aims to focus attention on this uncommon parasite through the presentation of a case report and an overview of the literature.

Case Description

A 1-year-old intact female Borzoi imported from Romania to Italy sneezed spontaneously a worm-like parasite specimen. Morphological and molecular diagnosis identified the parasite as a female of the zoonotic pentastomid L. serrata (so-called European tongue worm) that lives in the nasopharyngeal tract of canids. Eggs of Linguatula were detected in the feces. Molecular identification (99%-100% homology) was based on DNA extraction, polymerase chain reaction of a 700-bp fragment of the mitochondrial cytochrome c oxidase subunit I gene, and alignment with BLAST analysis. Due to the possibility of other adult or juvenile specimens of the parasite still occurring in the dog, a treatment attempt with a combination of febantel/pyrantel/praziquantel was made. No parasite eggs were detected in fecal samples after the drug was administered. Endoscopy confirmed the absence of adult parasites and slight pathological changes. A follow-up examination conducted 3 months after the treatment did not reveal any clinical and laboratory abnormalities.

Conclusion

Linguatula serrata appears to be currently prevalent in some European countries, but there are no recent extensive studies on the prevalence of canine linguatulosis, so the parasite frequently remains undetected and unreported in dogs as the diagnosis is often overlooked. Parasites not commonly found such as L. serrata can become increasingly prevalent and may be detected in imported dogs. Therefore, veterinarians must be aware of the possible presence of uncommon and exotic pathogens in these dogs, be able to recognize the relevant clinical signs, and diagnose the infection quickly. This will improve the prognosis in individual dogs, reduces the risk of possible public health implications, and reduces the risk of uncommon and exotic pathogens establishing new endemic foci.

Characterization of tongue worms, Linguatula spp. (Pentastomida) in Romania, with the first record of an unknown adult Linguatula from roe deer (Capreolus capreolus Linnaeus)

Specimens of the pentastomid parasite, Linguatula serrata, have been reported from several animals in Romania, including some domestic dogs translocated to other parts of Europe. In this study, gray wolves (Canis lupus, n = 80), golden jackals (C. aureus, n = 115), red foxes (Vulpes vulpes, n = 236), and roe deer (Capreolus capreolus, n = 1) were examined for pentastomes. Overall, 17.5% of wolves were found to be infected with specimens of Linguatula, with a range of infections of one to five individuals per animal. Golden jackals and foxes had much lower infection levels, with 1.73% of golden jackals and 1.69% of foxes infected; both host species were found to be infected with one or two individual pentastomes per animal. The single deer specimen was infected with three individual pentastomes. The pentastomes collected from the wolves and golden jackals were determined to be immature and mature adult specimens of L. serrata based on morphological examination and molecular analysis using the 18S rRNA gene. No pentastomes collected from the red foxes were available for identification. The pentastomes collected from the roe deer were expected to be L. arctica but determined to be mature adult male specimens of an unknown Linguatula, herein, referred to as Linguatula sp. based on its morphology; the results of molecular sequencing for the Linguatula specimen collected from the deer were inconclusive, preventing a final species identification. This study presents the first report of L. serrata in any hosts from Romania through both morphological and molecular characterization, and also presents the first report of a Linguatula sp. in Ca. capreolus, utilizing morphological characterization. Issues of morphological variability are discussed, including the presence of spines in the hook pit of specimens of Linguatula. This study highlights the need to examine all specimens of Linguatula to confirm the stage of development. Despite the inconclusive molecular result for some specimens, the authors still urge future researchers to incorporate a combined molecular and morphological approach in identifying specimens of Linguatula.

Linguatula serrata in an imported dog in Germany: Single-case or emerging disease?

Linguatula serrata is a worm-like parasite with zoonotic potential that inhabits the nasal cavities of canids. Although most cases of linguatulosis are associated with unspecific and rather mild respiratory symptoms, cases of unusual infestations and severe courses in both animals and humans have been reported. In central and northern Europe, the pathogen used to appear only sporadically, however, within the last few years the number of detections has increased noticeably. In July 2020 an approximately nine-month-old dog, imported from Romania, was presented in a veterinary practice in Gotha, central Germany, due to persistent worsening cough. Despite antibiotic treatment the tussis became more severe until the dog expectorated multiple worm-like structures. Three of these specimens were sent to the Institute of Parasitology (Faculty of Veterinary Medicine, University of Leipzig, Leipzig) for morphological and genetic species identification. The latter was based on a 1000-bp fragment of the mitochondrial cytochrome c oxidase subunit I gene (cox1) and the complete nuclear 18S rRNA gene. The dog presented in this study suffered from a severe respiratory impairment caused by worm-like parasites inhabiting its upper respiratory tract. The detected parasites were morphologically identified as female specimens of the so-called tongue-worm L. serrata, which was confirmed by pairwise alignment and phylogenetic analysis of the produced sequences. We report an unusually severe case of L. serrata infection in an imported dog and discuss the spread of this potentially dangerous parasite in central and northern Europe.

28S rRNA sequences for Linguatula spp

Identification of specimens belonging to the genus Linguatula (Pentastomida) is relatively easy due to their unique morphology. However, differentiation between species of Linguatula can be challenging for several reasons, including considerable differences between different developmental stages of the parasite within and between species. Currently, 18S rRNA and Cox1 sequences are the only available comparable sequences in GenBank, but recent research has discussed the utility of 28S rRNA for pentastomid phylogenetics. This study presents 28S rRNA gene sequences for two members of the genus Linguatula. Sequences of 28S rRNA were successfully obtained from well-identified samples of L.serrata (collected in Australia) and L.nuttalli (collected in South Africa), with voucher specimens. Phylogenetic analysis of the 28S rRNA region showed 6% difference between L.serrata and L.nuttalli, with low levels of intraspecific variation. In comparison, 18S rRNA and Cox1 sequences from the same specimens showed 0.23% and 13% interspecific differences, respectively. The results of this study show that 28S rRNA has greater genetic diversity to allow for improved differentiation between species of Linguatula than 18S rRNA but is on par with Cox1. Records that do not provide adequate morphological or molecular data to justify independent specific diagnoses must be regarded cautiously, and the need for continued research on species of Linguatula, using a combined morphological and molecular analysis, across a number of different hosts, development stages, geographical regions and molecular markers is highlighted.

Sebekia sp. (Eupentastomida, Sebekidae) in Pygocentrus piraya (Actinopterygii: Serrasalmidae) from marginal lagoons of the middle São Francisco River basin, Brazil

Pygocentrus piraya is an endemic species of the São Francisco River basin. In this study, 342 carnivorous fish were examined, nymphs specimens of Sebekia sp. and its ecological indexes are recorded only in piranhas, of the total of 53 collected from three marginal lagoons of the middle São Francisco River basin: 17 specimens from Curral de Varas lagoon; 15 from Maris lagoon, both of state of Minas Gerais; and 21 specimens from Mocambo lagoon, state of Bahia. The prevalence (P) and mean abundance (MA) of Sebekia sp. nymphs in intermediate hosts were as follows: in Curral de Varas lagoon, P = 11.8%, MA = 0.18; in Maris lagoon, P = 46.6%, MA = 0.47; and in Mocambo lagoon, P = 14.3%, MA = 1.05. Despite the lower number of fish examined from Maris lagoon, this lagoon had the highest number of piranhas (seven) parasitized by Sebekia sp. Pentastomids have zoonotic importance and evaluation of the indirect life cycle of sebekids in lagoons is necessary for defining the intermediate and final hosts involved. This record is novel and stems from collection of piranhas in the marginal lagoons of the São Francisco River, in the states of Minas Gerais and Bahia, Brazil.

Verification of the Spotted-Tail Quoll, Dasyurus maculatus, as a Definitive Host for the Pentastomid Linguatula sp. in Australia

PURPOSE

Specimens of a pentastomid, identified as a nymphal Linguatula serrata, have previously been reported from the nasal cavity of the endangered Australian marsupial, the spotted-tail quoll, Dasyurus maculatus. These specimens were made available for morphological and molecular characterisation to confirm their species identity.

METHODS

Specimens were examined by light microscopy. Molecular sequencing attempts were unsuccessful.

RESULTS

Examination showed that the specimens were adult pentastomes of the genus Linguatula. Morphological differences are reported between these specimens and published measurements of specimens from other hosts collected from the same region.

CONCLUSIONS

This is the first confirmed report of an adult Linguatula pentastome in a native Australian animal. Due to the small number of specimens and the lack of successful molecular characterisation, the pentastomes have been referred to Linguatula sp. until future work can confirm the species identity. The need for combined molecular and morphological analysis of pentastome specimens is reiterated.

Secrets of the Astute Red Fox (Vulpes vulpes, Linnaeus, 1758): An Inside-Ecosystem Secret Agent Serving One Health

An ecosystem’s health is based on a delicate balance between human, nonhuman animal, and environmental health. Any factor that leads to an imbalance in one of the components results in disease. There are several bioindicators that allow us to evaluate the status of ecosystems. The red fox (Vulpes vulpes, Linnaeus, 1758) has the widest world distribution among mammals. It is highly adaptable, lives in rural and urban areas, and has a greatly diverse diet. Being susceptible to environmental pollution and zoonotic agents, red foxes may act as sentinels to detect environmental contaminants, climatic changes and to prevent and control outbreaks of emerging or re-emerging zoonosis. This paper aims to compile the latest information that is related to the red fox as a sentinel of human, animal, and environmental health.

Verification of rabbits as intermediate hosts for Linguatula serrata (Pentastomida) in Australia

We confirm the presence of nymphs of the introduced pentastomid, Linguatula serrata, in the introduced rabbit, Oryctolagus cuniculus, in Australia, based on morphological and molecular results. Two nymphs were collected from a single rabbit near the Kosciuszko National Park in New South Wales. Unlike reports of nymphs from domestic animals, these nymphs were not encapsulated, despite having the morphological features of infective nymphs. The possibility of different development pathways in lagomorphs is discussed. Examination of feral deer for L. serrata was unsuccessful and potential reasons for a lack of infection in these animals are postulated. Our results reiterate the need for a combined morphological and molecular approach to the identification of L. serrata. Further sampling of a range of feral and native animals is required to determine the true range of intermediate hosts and their relative importance in the transmission of L. serrata in Australia.

Occurrence and characterisation of tongue worms, Linguatula spp., in South Africa

A total of 509 mammalian vertebrates, belonging to 76 species, were examined for infection with pentastomid parasites. These animals were from 8 of the 9 provinces in South Africa. Linguatulid pentastomes were found only in 7 animals, specifically the African Lion (n = 3) and African Buffalo (n = 4). Adult parasites were found in the lion but nymphs, of various stages, were found in the buffalo. A detailed morphological examination of adult parasites using both light and scanning electron microscopy techniques suggested the specimens were Linguatula nuttalli Sambon1922. Sequences of 18S ribosomal DNA and Cox1 regions obtained from both adult and nymph stages suggested they belong to the one species. Phylogenetic analyses of Linguatula spp. based on the 18S and Cox1 sequences available in GenBank and obtained in the present study showed a clear distinction between L. nuttalli, L. arctica and L. serrata (from Europe and Australia). Several specimens from the Palearctic region which were previously assumed to be L. serrata formed a distinct group in the phylogenetic tree suggesting they probably belong to a different, and as of yet, unknown species.

•

Genetic and morphological characterisation of Linguatula nuttalli in South Africa.

•

Occurrence of Linguatula nuttalli in 509 mammalian vertebrates, belonging to 76 species.

•

Phylogenetic analyses of Linguatula spp. from different continents.

Characterisation of the tongue worm, Linguatula serrata (Pentastomida: Linguatulidae), in Australia

We describe adult males and females and a nymph belonging to Linguatula serrata in Australia, based on light and scanning electron microscopies. In addition, 18S and Cox1 sequence data have also been provided and were compared with similar sequences in GenBank. Our specimens had identical 18S sequences and limited genetic distance in Cox1 region which fell within the intra-specific range observed for Linguatula spp. suggesting that they all belong to one species. Phylogenetic analyses showed that Australian specimens were grouped with L. serrata in Europe where the species was first found and described. A number of L. serrata from Iran and Bangladesh formed a distinct group. The genetic distance between these Linguatula and Australian/European L. serrata ranged from 0.46% to 2.21% which is larger than the genetic distance observed between L. arctica and Australian/European L. serrata (0.12%) suggesting that they belong to a different species. As pointed out previously by several other authors, L. serrata comprises more than one species and those from the Palearctic region (including Iran and Bangladesh) should not be automatically named L. serrata unless there is enough evidence for the identification. To accurately address the complex taxonomy of Linguatula spp. a detailed morphological and genetic characterisation of numerous developmental stages of the parasite is necessary, to ensure morphological differences are not due to development. This however may not be achievable in the near future due to significant reduction in expertise as well as research funding awarded in this area of research to understand the basics of our planet.

•

Detailed description of Australian tongue worms.

•

First genetic characterization of Linguatula serrata in Australia.

•

Specific identification of Linguatula serrata in Australia.

•

Taxonomic status of L. dingophila could be valid but requires further investigation.

A sensitive serodiagnostic tool for the detection of active infection of zoonotic visceral and nasopharyngeal linguatulosis

Aim:

This study aimed to evaluate the different serological techniques for early diagnosis of acute concurrent infections with linguatulosis in the definitive host (dogs) and an intermediate host (goats). This evaluation compared between the gold standard (GS) test (GS; examination of nasal and fecal samples in dogs and examination of lymph nodes in goats), sandwich enzyme-linked immunosorbent assay (S-ELISA), and indirect ELISA.

Materials and Methods:

Fifty goats and fifty dogs were examined for the presence of Linguatula serrata nymphs and adults, respectively, besides the collection of blood samples from the examined animals for serologic testing.

Results:

In goats; GS, S-ELISA, and indirect ELISA showed positivity in 32 (64%), 28 (56%), and 39 (78%) samples, respectively. In dogs; GS, S-ELISA, and indirect ELISA showed positivity in 25 (50%), 25 (50%), and 30 (60%) samples, respectively. S-ELISA displayed significant higher agreement with the GS test (≥0.83) than indirect ELISA (≤0.67) in both hosts. Infection with linguatulosis showed significant relation with the age of goats and dogs and the sex of goats (p<0.05).

Conclusion:

S-ELISA displayed more sensitivity and specificity for the detection of concurrent infections with linguatulosis in both dogs and goats than indirect ELISA, which could detect the prior infections. Similarly, these assays could be used for diagnosis of concurrent infections with linguatulosis in human, especially the chronic ones.

Status of Linguatula serrata infection in livestock: A systematic review with meta-analysis in Iran

Objectives

The present systematic review attempted to determine the prevalence of Linguatula serrata (L. serrata) infection among Iranian livestock. The L. serrata known as tongue worm belongs to the phylum pentastomida and lives in upper respiratory system and nasal airways of carnivores. Herbivores and other ruminants are intermediate hosts.

Methods

MEDLINE, Embase, Web of Science, Google Scholar, and the Cochrane Library were searched from Nov 1996 to 22 Apr 2019 by searching terms including "Linguatula serrata", "linguatulosis", "pentastomida", "bovine", "cattle", "cow", "buffalo", "sheep", "ovine", "goat", "camel", "Iran", and "prevalence" alone or in combination. The search was conducted in Persian databases of Magiran, Iran doc, Barakatkns (Iran medex) and Scientific Information Database (SID) with the same keywords. After reviewing the full texts of 133 published studies, 50 studies had the eligibility criteria to enter our review.

Results

By random effects model analysis, the pooled prevalence of linguatulosis was 25% (95%CI: 18.0-33.0, I ² = 98.67 % , P < 0.001) in goats; 15.0% (95%CI: 10.0-20.0, I ² = 97.95 % , P < 0.001) in sheep; 12.0% (95%CI: 7.0-18.0, I ² = 98.05 % , P < 0.001) in cattle; 7% (95%CI: 2.0-16.0, I ² = 97.52%) in buffalos and 11.0% (95%CI: 6.0-16.0%, I ² = 96.26 % , P < 0.001) in camels. The overall prevalence in livestock was estimated to be 25%. The highest infection rate was recorded in West Azerbaijan Province (68%) and the lowest rate was in Khuzestan Province (0.23%) (P < 0.05).

Conclusions

We concluded that the high prevalence of L. serrata infection in livestock (mainly ovine linguatulosis) show the endemic status of linguatulosis in several parts of Iran and will pose a risk for inhabitants. Control strategies to reduce the parasite burden among these animals are needed.

A zoonotic parasite, Linguatula serrata, infection in a dog imported from Ethiopia to the United States

A moderate number of oval-shaped, 114.7 × 61.3 μm in size, amber-colored, arthropod-like eggs that had chitinous, smooth, semi-thickened outer wall and 2-4 short appendages armed with 2 terminal hook-like structures were detected in multiple fecal samples from an approximately 9-month-old, intact female, collie-mixed dog that had been recently imported from Ethiopia to Oklahoma, United States. Initially the unusual arthropod-like eggs were considered to be a pseudoparasite, most likely mite eggs. However, based on the history of the dog, morphology of the eggs, and presence of the eggs in repetitive fecal flotations, a pentastomid, Linguatula serrata, was suspected. DNA extraction and PCR analysis of the partial 18S rRNA gene were performed on the eggs, and nucleic acid sequence showed 100% homology to L. serrata, a parasite of dogs, and L. arctica, a parasite of Norwegian reindeers. Rhinoscopy and head CT scan on the dog failed to demonstrate adult parasites or detect any pathologic changes. At this time, pentastomid eggs were no longer observed on fecal flotation. Due to the possibility of juvenile stages of the parasite still migrating in the dog, fluralaner (Bravecto®, Merck) was administered and continuing treatment recommended for at least 6 months. A follow-up fecal examination conducted a month after the treatment did not reveal any parasites or eggs. This is a case report of canine linguatuliasis diagnosed in Oklahoma, United States.

Prevalence of Linguatula serrata nymphs in slaughtered sheep from Tehran province, Iran

Linguatulosis is a zoonotic disease caused by Linguatula serrata. Ruminants are the most important intermediate hosts of this parasite. This study was carried out to evaluate the prevalence rate of Linguatula serrata infection in slaughtered sheep in slaughterhouses of Tehran province, Iran. A total of 767 slaughtered sheep were selected in 2016 using systematic random sampling and their mesenteric lymph nodes were examined for Linguatula serrata nymph detection. Then, the infection rate and its intensity in different ages, sex and seasons were assessed. It was revealed that 66 sheep (8.6%) were infected with Linguatula serrata nymphs. Intensity of the infection was 4.88 nymphs. The highest rate of infection was observed in sheep aged over 19 months (P≤0.05). The highest infection rate and intensity of the infection were recorded in winter and summer, respectively (P≤0.05). Besides, intensity of the infection in females was significantly higher than that in males (P≤0.05). This study indicates the importance of Linguatula serrata infection in sheep in Tehran province, and the need to improve preventive measures for reducing the rate of infection and preventing transmission of the infection from sheep and other ruminant to other animals and humans in Iran.