Ocular linguatuliasis in Ecuador: case report and morphometric study of the larva of Linguatula serrata

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.

Molecular characterization and phylogenetic analysis of Linguatula serrata isolated from camels, sheep and goats in Iran

Linguatula serrata is an important zoonotic parasite with worldwide distribution. The objective of the present study was to investigate the molecular characterization and phylogenetic analysis of nymphal stage of L. serrata from camels, goats and sheep in Iran. The mesenteric lymph nodes were collected from various ruminants including goats, sheep and camels at Isfahan and Shiraz slaughterhouses and the nymphs were identified using morphological characteristics. After DNA extraction, the 18 S rRNA and Cox1 genes were amplified by polymerase chain reaction. The sequencing of the genes was conducted using specific primers and a capillary DNA analyzer. The comparison of amplified sequences with existing data confirmed the presence of L. serrata with 99.6-100% nucleotide sequence similarity. Based on 18 S rRNA and Cox1 sequences, two isolates collected from sheep revealed 100% and 99.9% sequence identity, respectively. Also, three isolates from camel had 99.64-100% and 99.7-100% homology. Two isolates from sheep had 100% identity in their 18SrRNA gene and were categorized together, but showed 99.9% similarity in the Cox1 gene, not clustering together. Phylogenetic analysis of the Cox1 gene classified nearly all the isolates into L. arctica clade. It can be concluded that 18 S rRNA and Cox1 genes sequencing can be a proper method for the analysis of phylogenetic relationships of L. serrata among different hosts in different parts of Iran, possibly helpful for infection control and prevention.

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.

The first Linguatula serrata case in an imported dog in Finland

Linguatula serrata is a pentastomid parasite infecting carnivores as definitive hosts and herbivores as intermediate hosts. In carnivores, including dogs, it usually parasitises the nasal cavity and sinuses, causing upper respiratory signs. This case report presents the first canine Linguatula case in Finland in an imported dog originating from Spain. In addition to the unremarkable clinical history of the dog, the treatment, parasite's morphology and molecular analysis are described, and the zoonotic potential is discussed.

Global status of neglected human Linguatula infection: a systematic review of published case reports

Human linguatulosis is a rare but highly specialized pentastomid parasitic infection all around the world. The disease is caused by worm-like parasites which share some morphologic features of arthropods and annelids. The life cycle of Linguatula spp. is provided as an example of pentastomid biology. The adult forms of Linguatula spp. are found in the nasal passages and frontal sinuses of dogs and other canids, domestic animals, and humans. Infestation may occur in the viscera, where immature forms develop in the liver, spleen, lungs, eyes, and other organs, or in the nasopharyngeal area. This review includes previous studies on the genus Linguatula in Iran and other countries from 1940 to 2019. Considering a few reports of human infestation, a comprehensive search was performed on both English and Persian databases for publications reporting human cases all around the world. Finally, 30 papers of 62 human cases were included in this study. The mean age of the patients was 25.8 years (varied from 8 to 79 years). Altogether, 41 (66.1%) and 21 (33.9%) of the patients were female and male respectively. The maximum cases (n = 25) were from Sudan. Nasopharynx was the most frequently involved organ in human cases. Our findings offer that physicians should consider the Linguatula infection in patients with complaints like unexpected dysphagia, with coughing, sneezing, and vomiting, after consuming raw/undercooked contaminated ruminant's viscera.

Clinical manifestation and epidemiological findings of human linguatula serrate infection in Iran: systematic review

The aim of this study was to collect data and provide information on clinical diagnosis of disease, methods of dissemination, prevention and treatment of human linguatuliasis in order to increase people's awareness and health care. In this study case reports of individuals in Iran those infected with the Linguatula serrata were taken from the international databases (e.g., Medline (PubMed), Scopus, Iranmedex, Scientific Information Database, and Irandoc) and reviewed. The review covers the case reports of human tongue worm infection published either in Persian or in English between the years 1980-2018. An individual researcher undertook the bibliographic search and evaluation of articles based on inclusion/exclusion of specific criteria. Cases of infection have been reported in eight provinces of Iran. Dietary habits play the important roles in the transmission of the parasite. Clinical diagnosis was achieved by obtaining a patient's history, then completing a clinical examination of the mentioned patients. Symptoms of infection were mainly observed in the upper respiratory tract in most reports, the patient's status was improved by removing the parasite from the infected organ. Given that viscera of slaughtered livestock plays a significant role in the transmission of this infection to humans, Careful inspection of slaughtered livestock in slaughterhouses and Preventing the slaughter of livestock illegally and unsanitary, outside the slaughterhouse, is important. Accordingly, it is very important to train the employees working in the slaughterhouses and the people who consume these organs.

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.

Prevalence and associated risk factors of Linguatula serrata infection in definitive and intermediate hosts in Iran and other countries: A systematic review

Linguatula serrata is known as a cosmopolitan zoonotic parasite whose adult form inhabits the upper respiratory system, nasal airways and frontal sinuses of dogs, foxes, cats and other carnivores, which are recognized as its final hosts. Its immature form resides in mesenteric lymph nodes, liver, lungs and spleen of herbivorous and other ruminants, which serve as its intermediate hosts. Both adult and nymphal stages of L. serrata can infect humans, which typically occurs via ingestion of eggs of infected dogs or consumption of raw or undercooked infected viscera of contaminated herbivores. The most common form of infection in human is nasopharyngeal linguatulosis, also known as Halzoun syndrome or Marrara syndrome. This paper presents a review of previous studies on L. serrata conducted in Iran from 1969 to 2018 and other countries. It was found that despite the fact that many studies have been conducted in Iran, the rate of infection with this parasite has not been studied in some areas of the country. In addition, the rate of infection with L. serrata increased with the age of ruminant animals and it was significantly higher in some areas. The prevalence of L. serrata nymphal infections in most areas was higher in goats in comparison to the other animals which can be an important risk factor for human infection. Although there was no significant difference in the rate of infection among male and female animals, the prevalence of L. serrata in male animals was typically lower than females. There was no significant difference in the seasonality of nymph infection.

The complete mitochondrial genome of Linguatula serrata (tongue worm) isolated from a dog and phylogenetic analysis

The complete mitogenome of Linguatula serrata isolated from nasal cavity of a dog was characterized for the first time. The total size of the circular mitogenome was 15,328 bp consisting of 37 genes including 13 protein coding genes, 22 tRNA genes, two rRNA genes and two control regions. Phylogenetic tree was constructed based on 17 closely related species and their genetic relationship with Linguatula serrata was analysed.

A behavioral evaluation of the effects of ingestion of Linguatula serrata nymphs in rats

Nasopharyngeal linguatuliasis known as Halzoun or Marrara syndrome occurs following ingestion of raw or undercooked viscera, including lymph nodes, liver and lung of infected animals. The present study was aimed to investigate the behavioral changes induced by ingestion of Linguatula serrata nymphs in rats. For this purpose, 24 rats were divided into four groups and orally ingested with 0 (control), 15, 30 and 60 L. serrata nymphs, respectively. Sneezing, mouth and tongue movements and mouth opening numbers were counted and the duration of mouth and nose grooming was measured at 10-min blocks for 30 min. Ingestion of 0 (normal saline) number of nymph produced negligible behaviors, whereas 15, 30 and 60 numbers of nymphs increased the above-mentioned behaviors when compared to normal saline (0 nymph) group. In this context, 60 number of nymphs produced more behavioral changes than 15 nymphs. We concluded that ingestion of L. serrata nymphs can produce behavioral changes in orofacial area in rats.

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

Pentastomids are obligate zoonotic arthropod parasites utilising canids and vulpids as their definitive hosts and several herbivorous species as their intermediate hosts. Reported only 10 times in Australia over the last 150 years as incidental findings, adult Pentastomids referred to as Linguatula serrata have been encountered in nasal cavities of domestic and wild dogs, and foxes. Nymphs have been reported in cattle and rabbits. In the present study, a number of potential definitive hosts, including red foxes (Vulpes vulpes), wild dogs (Canis lupus dingo and C.l. dingo x C. familiaris) and feral cats (Felis catus), and intermediate hosts cattle (Bos taurus), sheep (Ovis aries), feral pigs (Sus scrofa), rabbits (Oryctolagus cuniculus), goats (Capra hircus) and a European hare (Lepus europaeus), from the highlands of south-eastern Australia were examined. Of the animals examined 67.6% of wild dogs (n = 37), 14.5% of red foxes (n = 55) and 4.3% of cattle (n = 164) were found to be infected with Pentastomids, herein identified as Linguatula cf. serrata. The common occurrence of the parasite in wild dogs and less frequently in foxes suggests these wild canids have potential to act as a reservoir for infection of livestock, wildlife, domestic dogs and possibly humans. The unexpected high frequency of the parasite in wild dogs and foxes in south-eastern Australia suggests the parasite is more common than previously realised. Of the potential intermediate hosts in the region, only 4.3% of cattle were found to be infected with pentastomid nymphs which suggest the search for the host(s) acting as the main intermediate host in the region should continue. Future studies should investigate transmission patterns, health impacts on hosts and whether the parasite has zoonotic significance in Australia.

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Linguatula sp. was common in wild canids in the highlands of south eastern Australia.

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The occurrence of adult Linguatula sp. in European red foxes in Australia is confirmed.

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Other than rabbits, wildlife intermediate hosts have not been identified.

A Case of Pentastomiasis at the Left Maxilla Bone in a Patient with Thyroid Cancer

Pentastomiasis, a zoonotic parasite infection, is typically found in the respiratory tract and viscera of the host, including humans. Here, we report for the first time an extremely rare case of intraosseous pentastomiasis in the human maxilla suffering from medication related osteonecrosis of the jaw (MRONJ). A 55-year-old male had continuously visited the hospital for MRONJ which had primarily developed after bisphosphonate and anti-neoplastic administration for previous bone metastasis of medullary thyroid cancer. Pain, bone exposure, and pus discharge in the right mandible and left maxilla were seen. Osteolysis with maxillary cortical bone perforation at the left buccal vestibule, palate, nasal cavity, and maxillary sinus was observed by radiologic images. A biopsy was done at the left maxilla and through pathological evaluation, a parasite with features of pentastome was revealed within the necrotic bone tissue. Further history taking and laboratory evaluation was done. The parasite was suspected to be infected through maxillary open wounds caused by MRONJ. Awareness of intraosseous pentastomiasis should be emphasized not to be missed behind the MRONJ. Proper evaluation and interpretation for past medical history may lead to correct differential diagnosis and therapeutic intervention for parasite infections.

First finding of nymphal stages of Linguatula serrata in a South American camelid, a vicuña from Peru

Linguatula serrata, a pentastomid, was found parasitizing the lungs of a vicuña (Vicugna vicugna) from Cuzco, Peru. A total of 13 larvae were found encysted in the parenchymal tissue of the lungs. All larvae were identified as nymphal stages of L. serrata by morphological methods Diagnosis was confirmed by molecular analysis amplifying the cytochrome c oxidase 1 gene of three nymphs. Nucleotide sequences from the isolates were compared to previous sequences from GenBank, and it showed high similarity between them (>99%). This finding constitutes the first detection of L. serrata in a South American camelid.

Nasal infestation by Linguatula serrata in a dog in the UK: a case report

A two-year-old, female neutered, cross-breed dog imported from Romania was diagnosed with nasal infestation of Linguatula serrata after she sneezed out an adult female. The dog was presented with mucopurulent/sanguinous nasal discharge, marked left-sided exophthalmia, conjunctival hyperaemia and chemosis. Computed tomography and left frontal sinusotomy revealed no further evidence of adult parasites. In addition, there was no evidence of egg shedding in the nasal secretions or faeces. Clinical signs resolved within 48 hours of sinusotomy, and with systemic broad-spectrum antibiotics and non-steroidal anti-inflammatory drugs. Recommendations are given in this report regarding the management and follow-up of this important zoonotic disease.

The role of Linguatula serrata nymph in transmission of enteric bacterial pathogens to internal organs in sheep

Linguatula serrata is a worldwide zoonotic parasite belong to phylum Athropoda. When the eggs are swallowed by intermediate host, the larvae are released in intestine and reach the mesenteric lymph nodes (MLNs) and occasionally liver, lungs, heart, kidneys, spleen, and other body organs by the blood and lymph circulation. There are a few evidences showing transmission of microorganisms by migrating L. serrata. The aim of this study was to determine the role of L. serrata nymph in transmission of enteric bacterial pathogens to internal organs of sheep. For this purpose 11 parasite positive and 11 parasite negative MLNs to L. serrata were obtained from the native slaughtered sheep and were examined microbiologically in terms of bacterial contamination. The average total bacterial count and Escherichia coli count in the parasite positive samples were respectively 6.7 and 3.3 times higher than parasite negative ones (P < 0.05). However no significant differences were found for Salmonella and intestinal enterococci between parasite positive/negative samples. This indicates that L. serrata nymphs play as vehicles for bacteria and so contaminate offal. L. serrata nymphs transfer some bacterial agents to internal organs and enhance post mortem spoilage of the infected organs. It is also able to transfer some bacterial pathogens to internal organs which could potentially be the etiology of severe infectious or even zoonotic diseases. Especially in some regions where the consumption of raw or semi-cooked lymph nodes and other visceral organs are common.

Molecular characterization and phylogeny of Linguatula serrata (Pentastomida: Linguatulidae) based on the nuclear 18S rDNA and mitochondrial cytochrome c oxidase I gene

Linguatula serrata, a cosmopolitan parasite, is commonly known as tongue worm belonging to the subclass Pentastomida.We collected the nymphal stage of the worm from mesenteric lymph nodes of cattle and identified these as L. serrata based on morphology and morphometry. The 18S rDNA sequences showed no intraspecific variation, although cox1 sequences showed 99.7–99.9% homology. In the phylogenies inferred from both gene loci, members of the genus Linguatula (order Porocephalida) were closer to those of the order Cephalobaenida than to those of Porocephalida, reflecting a mismatch with the corresponding morphology-based taxonomy. Accordingly, analyses of additional gene loci using a larger number of taxa across the Pentastomida should be undertaken to determine an accurate phylogenetic position within the Arthropoda.

Ocular pentastomiasis in the Democratic Republic of the Congo

Ocular pentastomiasis is a rare infection caused by the larval stage of pentastomids, an unusual group of crustacean-related parasites. Zoonotic pentastomids have a distinct geographical distribution and utilize reptiles or canids as final hosts. Recently, an increasing number of human abdominal infections have been reported in Africa, where pentastomiasis is an emerging, though severely neglected, tropical disease. Here we describe four ocular infections caused by pentastomids from the Democratic Republic of the Congo. Two cases underwent surgery and an Armillifer grandis infection was detected by morphological and molecular approaches. Thus far, 15 other cases of ocular pentastomiasis have been reported worldwide. Twelve cases were caused by Armillifer sp., recorded almost exclusively in Africa, where such infections occur as a consequence of hunting and consuming snakes, their final hosts. Seven further cases were caused by Linguatula serrata, a cosmopolitan pentastomid whose final hosts are usually canids. Intraocular infections caused permanent visual damage in 69% and a total loss of vision in 31% of reported cases. In contrast, ocular adnexal cases had a benign clinical course. Further research is required to estimate the burden, therapeutic options and pathogenesis of this neglected disease.

Linguatula serrata (Porocephalida: Linguatulidae) Infection among Client-Owned Dogs in Jalingo, North Eastern Nigeria: Prevalence and Public Health Implications

Pentastomiasis is a parasitic zoonosis endemic to western and central Africa. This study was undertaken to determine the prevalence and public health implications of Linguatulosis in client-owned dogs in Jalingo, North Eastern Nigeria. Seven hundred and seventy seven (777) dogs brought for treatment at the hospital were subjected to buccal (sublingual) examination for pentastomiasis. Parameters such as age, sex, and breeds were determined. Also, the months of the year were taken into consideration. An overall prevalence of 37.45% was recorded. Of the 477 dogs examined in 2010, 184 were positive representing prevalence of 38.57% and in 2011 107 were positive representing prevalence of 35.67%. The infection was higher in the male than in the female which does not differ significantly (P > 0.05). There was no significant difference between sexes (P > 0.05). However, significant difference (P < 0.05) was observed between breeds and age of dogs examined. Season did not have much influence on the prevalence of Linguatulosis. The high prevalence of Linguatulosis in dogs and other animals found in this study highlights the need of improving preventative measures to reduce the rate of infection, which may pose a hazard to human health.

Prevalence of Linguatula serrata nymphs in slaughtered sheeps in Isfahan province, southwest of Iran

Linguatula serrata, well known as tongue worm; is an aberrant cosmopolitan parasite, which inhabits the carnivorous mammals (especially Canidae) respiratory system. The discharged eggs infect many plant feeder animals including human that produces visceral and nasopharyngeal linguatulosis which is known as Marrara syndrome in man. In current study, the prevalence rate of infection with L. serrata nymphs in mesenteric and mediastinal lymph nodes (MLNs) of slaughtered sheeps was investigated in Esfahan Province, Iran. The MLNs of 506 slaughtered sheeps, including 236 females and 270 males, were examined for L. serrata nymphs by cutting the MLNs longitudinally and then microscopic studies for L. serrata nymphs. Sheeps were categorized into four age groups, including <1 year, 1-2 years, 2-3 years and >3 years. Results showed that 11.66 % of examined sheeps were infected with L. serrata. Age had significant effect on the prevalence rate of this parasite in sheeps (infection in sheeps with >3 years old was more than other groups significantly) and sex had no significant effect on the prevalence rate of this parasite in sheeps. Infection rate in winter was significantly lower than infection rate in spring; but there were no significant differences between the other seasons. As high prevalence rate of infection in sheeps, suggesting possibly similar high rate of infection in other animals and man in the investigated area, which this emphasizes undertaking strict control measures to reduce risk of zoonotic outbreaks. This study was demonstrated infection rate of L. serrata in sheeps in central parts of Iran.

Occurrence of Linguatula serrata nymphs in cattle slaughtered in Tabriz, Iran

The Linguatula serrata is a tongue-shaped parasite that infects carnivores or insectivorous reptile as final and herbivores as intermediate host. The aim of this study was to evaluate the prevalence of nymphal stages of L. serrata in mesenteric nodes (MLN) and mediastinal lymph nodes of cattle slaughtered in Tabriz slaughterhouse, North West of Iran. Mesenteric and mediastinal lymph nodes of 640 cattle of different sex and age were inspected. A digestion method was applied for investigation of samples revealing an infection prevalence of 18.9 %. The MLNs in 97 cattle out of 640 (15.1 %) and the mediastinal lymph nodes in 47 cattle out of 640 (7.3 %) were infected by L. serrata nymphs. The results showed infection rate of mesenteric lymph nodes higher than mediastinal mesenteric lymph nodes (P < 0.05). The infection rate increased with age (P < 0.05). Although a significant difference seen in the infection rate between male and female but it was not significant at the same age groups of male and female (P > 0.05). In addition, there was a significant difference in the infection rate of different seasons (P < 0.05). Linguatulosis occurs as an endemic zoonosis in the northwest of Iran and has an active transmission life cycle.

Childhood pentastomiasis: a report of three cases with the following-up data

Pentastomiasis, a zoonotic parasitic disease, has been reported commonly in Africa and Asia. It is caused by pentastomes, which are annulated but unsegmented blood-sucking endoparasites. Fewer than 20 cases have been reported during the past two decades in China, and cases in children have been especially rare. Herein, we report three cases of pediatric patients with severe systemic symptoms, focusing on the clinical features, diagnosis, and therapy of this disease. The patients were two boys and one girl aged 3 to 13years. They all had a history of snake or worm ingested from snake and initial symptoms of fever, abdominal pain, diarrhea, and weight loss. Eosinophilia, anemia and elevated serum IgE levels were noted. Moreover, the large numbers of nodules, or even calcification, in the liver and/or lungs were noted by ultrasound, CT or MRI scans. These pentastomes were identified as Armillifer moniliformis, Porocephalus taiwana and Armillifer agkistrodontis. Praziquantel and mebendazole deworming treatments were adopted for the patients. Hence, pentastomiasis should be considered in the differential diagnosis for patients with multiple organ or system lesions, especially abdominal signs, that develop after the ingestion of snakes. Ultrasound, CT and MRI scans and laparoscopic approaches might be helpful for the diagnosis.

Histopathological changes caused by the nymph stage of Linguatula serrata in the mesenteric lymph nodes of goats

Linguatula serrata (Fröhlich, 1789) is a ubiquitous parasite species belonging to pentastomids, which has been reported frequently from domestic herbivores of Iran. This study was carried out to elucidate the pathological changes caused by the nymphal stage of L. serrata in the mesenteric lymph nodes (MLNs) of goats. Jejunal and ileal MLNs of slaughtered goats infected with L. serrata were collected and fixed in 10% neutral formal saline. Histopathological changes included follicular necrosis accompanied by a loss of lymphocytes and oedematous cystlike spaces. Granulomatous lesions were formed by mononuclear cell infiltration and necrotic tissue. Some lymphocytes were apoptotic with chromatolysis. A more frequent vascular abnormality was vasculitis. These findings show that larval migration is the main factor to initiate trauma and cause irritation in the MLNs of goats. Since goats are habitual intermediate hosts in Iran, rigorous inspection of the MLNs of slaughtered goats is recommended in order to decrease the chance of human infection through the consumption of raw visceral organs of goats.

Linguatula serrata tongue worm in human eye, Austria

Linguatula serrata, the so-called tongue worm, is a worm-like, bloodsucking parasite belonging to the Pentastomida group. Infections with L. serrata tongue worms are rare in Europe. We describe a case of ocular linguatulosis in central Europe and provide molecular data on L. serrata tongue worms.

Prevalence, biology, pathology, and public health importance of linguatulosis of camel in Iran

Linguatula serrata is a cosmopolitan zoonotic parasite with its adult form occurring in the nasal and respiratory passages of canids as the definitive hosts, while its immature stages localize in the mesenteric lymph nodes, liver, spleen, lungs, and, rarely, in other organs, such as the ocular region of herbivorous intermediate hosts. Humans can behave as both intermediate and final host and are infected by visceral and nasopharyngeal linguatulosis. Consumption of infected, improperly cooked viscera of the intermediate hosts, including sheep, goats, cattle, camels, or other herbivores containing the larval stages of this parasite is a potential source of infection of human beings with the nasopharyngeal form of linguatulosis. However, nasopharyngeal secretions or feces of carnivores containing eggs of Linguatula are the main sources for infecting human beings with the visceral form of this infection. In the present study, the prevalence of infection by nymphs of L. serrata in 101 camels in Yazd Province, central Iran, was estimated based on histopathological studies of samples from two, apparently enlarged, mesenteric lymph nodes (MLN), together with one sample from a whitish pinpoint spot on the liver and spleen of each animal. Thirteen camels (12.9%) were infected with the nymphal stage of L. serrata. Age and sex did not play a significant role in the prevalence of this parasitic infection. The number of parasites in each MLN ranged from one to six larvae. In view of the consumption of raw or undercooked liver and visceral organs of camel by humans of this region, the importance of careful inspection at slaughter needs to be emphasized.

Diagnosis of human visceral pentastomiasis

Visceral pentastomiasis in humans is caused by the larval stages (nymphs) of the arthropod-related tongue worms Linguatula serrata, Armillifer armillatus, A. moniliformis, A. grandis, and Porocephalus crotali. The majority of cases has been reported from Africa, Malaysia, and the Middle East, where visceral pentastomiasis may be an incidental finding in autopsies, and less often from China and Latin America. In Europe and North America, the disease is only rarely encountered in immigrants and long-term travelers, and the parasitic lesions may be confused with malignancies, leading to a delay in the correct diagnosis. Since clinical symptoms are variable and serological tests are not readily available, the diagnosis often relies on histopathological examinations. This laboratory symposium focuses on the diagnosis of this unusual parasitic disease and presents its risk factors and epidemiology.

The occurrence of nymphal stage of Linguatula serrata in water buffaloes (Bubalus bubalis): nymphal morphometry and lymph node pathology

The mesenteric lymph nodes (MLN) of buffaloes (n = 100) were examined for the presence of parasitic infection. The nymphal stage of Linguatula serrata was observed in two buffaloes. A single white-coloured nymph with transversely striated spines on a segmented body, two pairs of oral suckers and hooks was observed in the MLN. The morphometrics of the nymphs were studied. The affected lymph nodes were grossly enlarged with cyst and showed pathological lesions of fibroblastic reaction with a mild underlying inflammatory zone.