Emergence of Thelaziosis Caused by Thelazia callipaeda in Dogs and Cats, United States.

We report 2 autochthonous feline thelaziosis cases caused by the eyeworm Thelazia callipaeda and discuss the spread among dogs in the northeastern United States. Phylogenetic analysis suggests the parasite was introduced from Europe. Adopting a One Health approach is needed to limit further spread of T. callipaeda eyeworms in North America.

Thelazia callipaeda Eyeworms in American Black Bear, Pennsylvania, USA, 2023.

We identified a Thelazia callipaeda eyeworm in an American black bear in Pennsylvania, USA, on the basis of its morphological features and molecular analysis. Our finding highlights emergence of a T. callipaeda worm sylvatic transmission cycle in the United States.

Prevention of Thelazia callipaeda Reinfection among Humans.

Thelazia callipaeda is a zoonotic vector-borne nematode that infects and causes eye disease among a wide range of domestic and wild mammals, including humans. We describe an unusual case of reinfection by this nematode in Serbia and call for a focus on preventive measures in endemic areas.

Pruritic Cutaneous Nematodiasis Caused by Avian Eyeworm Oxyspirura Larvae, Vietnam.

A 41-year-old man from Son La Province, Vietnam, sought care for disseminated prurigo-like skin lesions from which nematode larvae were emerging. We morphologically and molecularly identified the larvae as Oxyspirura sp. Our findings confirm this nematode species as a zoonotic pathogen for emerging disease.

Survival of Phortica variegata experimentally and naturally infected with Thelazia callipaeda.

Knowledge of the effects that Thelazia callipaeda (Spirurida, Thelaziidae) infection has on the survival of its vector Phortica variegata (Drosophilidae, Steganinae) is scarce. The present study aimed to: (a) assess the rate of infection between experimentally infected (EI) and not experimentally infected (NEI) flies and (b) determine how T. callipaeda infection may affect the survival of P. variegata. In addition, fat composition was evaluated in flies that died during overwintering. Molecular analysis showed that T. callipaeda prevalence in flies that died before experimental infection, plus those from the NEI group, is 0.75% (i.e. 11 out of 1462 individuals). The EI group showed a significantly higher positivity to T. callipaeda (i.e. 51 out of 682 individuals; 7.48%) compared with the NEI group (i.e. 9 out of 750 individuals; 1.2%). Thelazia callipaeda DNA was detected until 147 days after experimental infection. This demonstrates that larvae of this eyeworm may survive in the fly for a significant period of the winter. Fat composition analysis showed that flies produced more unsaturated than saturated fatty acids during diapause, probably because unsaturated fatty acids remain in a liquid state at lower temperatures, providing anti-freeze properties to survive winter.

First report of Thelazia callipaeda in a free-ranging Iberian wolf (Canis lupus signatus) from Spain.

Thelazia callipaeda (Spirurida, Thelaziidae) is a vector-borne zoonotic eyeworm able to infect a broad spectrum of carnivores. Here, we describe the first case of bilateral infection by T. callipaeda in the eyes of an adult female Iberian wolf (Canis lupus signatus) in central Spain. Nematodes collected were morphologically identified (n = 42), and two specimens were molecularly characterized. At the sequence analysis of the partial mitochondrial cytochrome c oxidase subunit 1 gene, T. callipaeda haplotype 1 (the only haplotype circulating in Europe) was detected. The role of the Iberian wolf as a natural reservoir for T. callipaeda in the life cycle of this emerging zoonosis and the implications in conservation are discussed.

Quantitative analysis of Northern bobwhite (Colinus virginianus) cytokines and TLR expression to eyeworm (Oxyspirura petrowi) and caecal worm (Aulonocephalus pennula) glycoproteins.

Helminth parasites have been a popular research topic due to their global prevalence and adverse effects on livestock and game species. The Northern bobwhite (Colinus virginianus), a popular game bird in the USA, is one species subject to helminth infection and has been experiencing a decline of > 4% annually over recent decades. In the Rolling Plains Ecoregion of Texas, the eyeworm (Oxyspirura petrowi) and caecal worm (Aulonocephalus pennula) helminths are found to be highly prevalent in bobwhite. While there have been increasing studies on the prevalence, pathology, and phylogeny of the eyeworm and caecal worm, there is still a need to investigate the bobwhite immune response to infection. This study utilizes previously sequenced bobwhite cytokines and toll-like receptors to develop and optimize qPCR primers and measure gene expression in bobwhite intramuscularly challenged with eyeworm and caecal worm glycoproteins. For the challenge experiments, separate treatments of eyeworm and caecal worm glycoproteins were administered to bobwhite on day 1 and day 21. Measurements of primary and secondary immune responses were taken at day 7 and day 28, respectively. Using the successfully optimized qPCR primers for TLR7, IL1ß, IL6, IFNα, IFNγ, IL10, and ß-actin, the gene expression analysis from the challenge experiments revealed that there was a measurable immune reaction in bobwhite in response to the intramuscular challenge of eyeworm and caecal worm glycoproteins.

Periocular thelaziasis presenting as an orbital mass - a case report.

Thelazia callipaeda is a rare parasitic infestation caused by spiruroid nematode of the genus Thelazia. We report a case of a 74-year-old gentleman who presented with a painless swelling of left lower lid since 15 days. Examination revealed a firm mobile mass along the inferior orbital rim. Magnetic Resonance Imaging showed a well-defined preseptal cystic lesion and Ultrasound screening revealed multiple mobile worms within. Patient underwent cyst excision in toto under local anesthesia. Four long refractile worms were isolated from within the cyst cavity. Species identification confirmed the parasite as Thelazia callipaeda. Periocular thelaziasis usually presents as free floating worms in the conjunctival sac, anterior chamber or vitreous cavity. It is important to be aware of this rare entity which should be considered as a differential diagnosis in endemic areas.

A Pediatric Case of Thelaziasis in Korea.

In the present study, we intended to report a clinical pediatric case of thelaziasis in Korea. In addition, we briefly reviewed the literature on pediatric cases of thelaziasis in Korea. In the present case, 3 whitish, thread-like eye-worms were detected in a 6-year-old-boy living in an urban area and contracted an ocular infection known as thelaziasis incidentally during ecological agritainment. This is the first report of pediatric thelaziasis in Seoul after 1995.

A Case of Larval Oriental Eye Worm, Thelazia callipaeda, Infection Overlooked in Routine Ophthalmic Practice.

Thelazia callipaeda, the oriental eyeworm, is a zoonotic parasite that primarily infects the eyes, causing symptoms such as foreign body sensation, tearing, and itching. It is transmitted by fruit flies like Phortica okadai and commonly affects dogs and cats. This case report describes an 18-year-old woman who presented with complaints of "a worm in her left eye." Despite two visits to an ophthalmology clinic, she was initially diagnosed with conjunctivitis. The patient's history of dog ownership raised the possibility of zoonotic transmission; however, the worm was not detected during clinical examinations. Eventually, the patient removed the worm herself, and it was identified as the larval stage of T. callipaeda. This case emphasizes the importance of considering T. callipaeda in patients with nonspecific conjunctivitis symptoms, especially those with a history of contact with animals. It highlights the challenges in diagnosing this rare infection due to its nonspecific presentation and the small size of the larvae. Clinicians should be aware of this possibility and conduct thorough examinations, including double eversion of the eyelids, to avoid misdiagnosis and ensure appropriate treatment.

Update on infections with Thelazia callipaeda in European wildlife and a report in a red fox, Vulpes vulpes, in Portugal.

Thelazia callipaeda, also known as the "oriental eye worm", is a zoonotic parasitic nematode with a wide range of hosts, particularly wild and domestic carnivores, but also lagomorphs and humans. Currently, ocular thelaziosis presents an expanding distribution range throughout Europe, including Portugal. This study provides an update on T. callipaeda infection reports (30 studies) in European wildlife comprising 54 host-locality records in 10 host species from nine European countries. The prevalence of T. callipaeda varied widely, with ranges from around 1% in red foxes and European hares to almost 50% in red foxes. The lowest mean intensity was 2.7 nematodes/host in European wildcats and the highest was 38.0 nematodes/host in wolves. In addition, a massive infection with T. callipaeda in a juvenile male red fox from eastern-central Portugal is also described, representing the southernmost report in a wild animal in this country. A total of 188 nematodes (139 females and 49 males) were collected from both eyes and were submitted to morphological and molecular characterization. Collected nematodes were morphologically identified as T. callipaeda. Given the endemicity of T. callipaeda in eastern-central Portugal, surveillance system should be implemented to monitor its presence among wild and domestic animals.

IMPLICATIONS OF TREATING PARASITIC INFECTION IN NORTHERN BOBWHITE (COLINUS VIRGINIANUS) ON OVERALL HELMINTH LIFE CYCLE.

This study was conducted to determine how reducing the parasite burden in a definitive host may affect the prevalence in intermediate hosts. Here we used the eyeworm Oxyspirura petrowi and cecal worm Aulonocephalus pennula as model species. Northern bobwhite quail (Colinus virginianus) were provided an anthelmintic medicated feed in wild systems because of convincing evidence that these parasites were suppressing their populations. Eyeworm and cecal worm prevalence were measured in Orthopterans, which act as intermediate hosts, using polymerase chain reaction. Individuals were collected from a control site, a site treated for 2 yr, and a site treated for 5 yr. Orthopteran community composition was significantly different among the sites; however, an interaction between subfamily and site was not significant for the eyeworm. There was a significant reduction in eyeworm-infected Orthopterans on the 5-yr site compared with the other 2, suggesting that treatment of a definitive host may indeed affect the prevalence of eyeworms during other life-cycle stages. There was an interaction between the Orthopteran subfamily and the site for the cecal worm, so results were analyzed within each subfamily. A significant reduction in the prevalence of cecal worms was only found in the Cyrtacanthacridinae subfamily on the 5-yr site when compared with the other sites. However, the greatest prevalence in the Gomphocerinae and Oedipodinae subfamilies across all 3 sites was 4.1%. This indicates an unknown degree of cecal worm host specificity. Therefore, conclusions could not be made through the simple assessment of prevalence.

First report of Thelazia callipaeda Railliet & Henry, 1910 in a zoo lion (Panthera leo) (Linnaeus, 1758) from Romania.

Thelazia callipaeda, the zoonotic "oriental eye worm", is an emerging nematode known to infect a wide range of hosts, particularly carnivores (wild and domestic canids and felids, mustelids, and ursids), but also other mammal groups (suids, lagomorphs, monkeys, and humans), across a wide geographical area. New host-parasite associations and human cases have mostly been reported in endemic areas. A less studied group of hosts is represented by zoo animals that may harbor T. callipaeda.A 23-year old male lion (Panthera leo) that was born in a public zoo in Reșița (Caraș-Severin County, Romania) was submitted to the University of Agricultural Sciences and Veterinary Medicine of Cluj-Napoca for investigations after death from unknown reasons in November 2022. Four nematodes were collected from the right eye during the necropsy and submitted to morphological and molecular characterization.Collected nematodes were morphologically identified as three females and one male T. callipaeda. The BLAST analysis revealed 100% nucleotide identity to numerous isolates of T. callipaeda haplotype 1.The present paper presents a new host-parasite association between T. callipaeda and P. leo from a zoo in Romania.

Molecular characterization of oriental eyeworm (Thelazia callipaeda) detected from raccoon (Procyon lotor) and Japanese raccoon dog (Nyctereutes viverrinus) in Kanto region, Japan.

BACKGROUND: The oriental eyeworm Thelazia callipaeda (Spirurida: Thelaziidae) is an emerging parasitic ocular nematode of carnivores and humans. In domestic animals and humans, the infection causes varying degrees of inflammation and lacrimation, and wild carnivores represent an important reservoir. In this study we examined the infection status and molecular characterization of T. callipaeda in two urban carnivores, raccoons Procyon lotor and wild Japanese raccoon dogs Nyctereutes viverrinus, in the Kanto region of Japan. METHODS: From January 2020 to December 2021, 193 carcasses including 178 raccoons and 15 raccoon dogs were examined for the presence of worms in the eye. The worms from infected animals (one worm per host) were morphologically identified as T. callipaeda. Worms (1-5 worms per host) were subjected to genetic analysis using mitochondrial cytochrome c oxidase subunit I gene sequences. RESULTS: The prevalence of T. callipaeda in raccoons and Japanese raccoon dogs was 20.2% (36/178) and 13.3% (2/15), respectively. The cox1 sequences from 56 worms from 38 animals revealed three haplotypes (h9, h10, and h12). Analysis of multiple worms for five raccoons showed co-infection of two different haplotypes (h9 and h10) in a single host. Comparing our data with published sequences, three sequences obtained from raccoons and raccoon dogs shared the same haplotypes as those reported in humans, dogs, and cats in Japan. CONCLUSIONS: Our findings show a high prevalence of T. callipaeda in raccoons, suggesting that this invasive carnivore species serves as an important natural reservoir of T. callipaeda in the Kanto region of Japan, an area with the highest human population of the country.

MOLECULAR IDENTIFICATION OF INSECT INTERMEDIATE HOSTS WITH POTENTIAL PARASITE TRANSMISSION TO THE DEFINITIVE HOST NORTHERN BOBWHITE (COLINUS VIRGINIANUS).

Grassland birds have been declining substantially for the past several years. Habitat loss, degradation, and fragmentation as well as climate change are all thought to be the main drivers of the decline. However, as the declines continue to accelerate, it is becoming imperative to examine other factors that may contribute to population fluctuations. The nematodes Oxyspirura petrowi, Aulonocephalus pennula, and Physaloptera sp. are commonly found infecting northern bobwhite (Colinus virginianus), a game species of economic importance, and all 3 nematodes use insects as an intermediate host. Here we used polymerase chain reaction techniques to determine the occurrence of the 3 nematodes in 7 insect orders to uncover epidemiological patterns of the greatest potential for transmission to northern bobwhite. Insects were collected from March through September using sweep nets and pitfall traps. An R × C chi-squared test with Monte Carlo simulation was used to determine differences in the occurrence of the parasites across taxa and time. The results of the statistical analysis showed the nematodes are predominantly found in the order Orthoptera, and A. pennula and Physaloptera sp. showed epidemiological patterns in insects. However, no such pattern was observed with O. petrowi. An explanation for the lack of epidemiological pattern in O. petrowi is proposed and the diversity of known insect hosts of the 3 nematodes is increased.

The first human case of Thelazia callipaeda infection in Vietnam.

A 26-year-old man residing in a village of Thai Nguyen Province, North Vietnam, visited the Thai Nguyen Provincial Hospital in July 2008. He felt a bulge-sticking pain in his left eye and extracted 5 small nematode worms by himself half a day before visiting the hospital. Two more worms were extracted from his left eye by a medical doctor, and they were morphologically observed and genetically analyzed on the mitochondrial cytochrome c oxidase 1 gene. The worms were 1 male and 1 female, and genetically identical with those of Thelazia callipaeda. By the present study, the presence of human T. callipaeda infection is first reported in Vietnam.

First report of human Thelazia callipaeda infection in Portugal.

The zoonotic parasitic nematode Thelazia callipaeda, also known as the oriental eye worm, is endemic in several European countries, including Portugal. Infections may result in ocular disease in domestic and wild animals as well as humans, with more or less severe manifestations. We report the first human case of ocular thelaziosis by T. callipaeda in Portugal, a country where the parasite had already been found to infect dogs, cats, red foxes, wild rabbits and a beech marten. An 80-year-old patient from east-central Portugal, who had been suffering from tearing for a few years, had whitish filiform fragments removed from the left eye. Polymerase chain reaction of partial cytochrome c oxidase subunit 1 and 18S small subunit rRNA genes followed by bidirectional sequencing and BLAST analysis confirmed T. callipaeda haplotype 1, the only haplotype previously reported in Europe. The endemicity of T. callipaeda in domestic and wild animals in east-central Portugal makes it very likely that infection of the human patient had occurred locally. In east-central and other geographical areas of Portugal, veterinarians and physicians, especially ophthalmologists, should regard T. callipaeda as a cause of ocular pathology in animals and humans.

Thelazia callipaeda in Slovakia - From sporadic cases to endemic areas.

Spirurid nematode Thelazia callipaeda, transmitted by the fruit fly Phortica variegata, is a causative agent of an ocular parasitic disease called also canine thelaziosis. Dogs, cats, and wild canids are considered the primary definitive hosts for the parasite, but humans may also serve as aberrant definitive hosts. For long decades the geographic range of T. callipaeda was strictly limited to the territory of Asia, but after the year 2000, the parasite began to spread rapidly through Europe. The first autochthonous infections of dogs and foxes in Slovakia were recorded in 2016. In the present study, the results of a whole-area surveillance for canine thelaziosis are reported. Altogether, 142 cases of infection caused by T. callipaeda were diagnosed by veterinarians in dogs between 2016 and the first quarter of 2021, and two cases of feline thelaziosis were recorded. The majority of the dogs showed mild ocular signs manifested by conjunctivitis; 8.5% of them suffered from more serious mucopurulent discharge, and in two dogs corneal ulceration was recorded. The screening revealed increasing trends in the occurrence of canine thelaziosis from both a temporal and spatial point of view and unambiguously confirms the endemic status of T. callipaeda in Slovakia with the prospect of its further expansion.

Wild carnivores and Thelazia callipaeda zoonotic eyeworms: A focus on wolves.

Thelazia callipaeda is a zoonotic parasite causing ocular disease in domestic dogs, cats, several wild carnivores, hares, and humans. This nematode is widely distributed in Europe, where it is transmitted by the drosophilid fly Phortica variegata. Since the first report of infection in grey wolves (Canis lupus) from southern Italy, other cases of thelaziosis have been recorded in this animal species throughout Europe, raising questions about their role in spreading T. callipaeda. Indeed, for their wandering behavior through long distances and living in woody areas where the vectors thrive, wolves may act as reservoirs and spreaders of thelaziosis. In this study we reviewed the literature about wolves acting as reservoirs of T. callipaeda in Europe. In addition, we report the first detection of T. callipaeda eyeworms in grey wolves in the Italian Alps, discussing its possible implications in the epidemiology of thelaziosis in the Alpine landscape. Animals (n = 3) included in this study were originated from the Italian Alps, one juvenile male wolf was found dead, and the other two were seven-year-old males translocated from Piedmont region to a Zoological Garden, in Tuscany. All animals were infected with eyeworms, which were morphologically and molecularly identified as T. callipaeda. Data herein presented confirm those available in the literature about the circulation of a unique cox1 haplotype in Europe. In addition, the report of T. callipaeda in wolves from the Alps suggests an ecological continuity of habitats which are suitable for the distribution of T. callipaeda from the southern to northern Italy through the Apennine backbone. Retrospectively, it could also explain the spreading of the oriental eyeworm infection in Europe over the last 20 years with many wild carnivores, such as foxes and possibly wolves, playing a pivotal role as reservoirs of the infection for dogs, cats and humans.

Zoonotic Thelazia callipaeda eyeworm in brown bears (Ursus arctos): A new host record in Europe.

Thelazia callipaeda (Spirurida, Thelaziidae) eyeworm, a zoonotic parasite transmitted by lachryphagus drosophilids, causes subclinical to clinical ocular disease in a wide range of vertebrates, including humans. In the past 20 years, the infection spread primarily in areas where the vector thrives, and now is endemic in many European countries. Recently, this nematode has been reported also in the United States. Here, we describe the first record of the brown bear (Ursus arctos) as a host of T. callipaeda. Eight (26.7%) out of 30 bears were found to be infected with T. callipaeda adult worms. In addition, the parasite was detected in 13 wolves (Canis lupus) sharing the same environment with the brown bears. At the molecular characterization, all nematodes belonged to the haplotype 1, which is the only one recorded in Europe, as yet. This finding demonstrates that brown bears may act as hosts for this parasite, suggesting its potential role in the maintenance of the cycle not only in the wild but also in captivity. Under the above circumstances, the brown bear may represent a potential zoonotic risk for humans, both in rural and urban areas where other reservoirs may be infected.