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.

Macrophage migration inhibitory factor of Thelazia callipaeda induces M2-like macrophage polarization through TLR4-mediated activation of the PI3K-Akt pathway.

Macrophage migration inhibitory factor (MIF), an immunoregulatory cytokine plays an important role in inflammation and the immune response, and has been described as having a potential role in immune evasion by parasites. Thelazia callipaeda, a vector-borne zoonotic eye worm with a broad host range, has been documented as an agent of ocular infection of thelaziosis. The ability of T. callipaeda to persist in an immunologically competent host has led to the suggestion that it has evolved specific measures to counter immune defenses. To date, whether the immune evasion of T. callipaeda is related to MIF and the possible related signaling pathway and molecular mechanism have remained unclear. In the present study, we examined the effect of T. callipaeda MIF (T. cp-MIF) on macrophages. We analyzed the antigenic epitopes of the candidate T. cp-MIF and found that it exhibited an ideal antigenic index. Morphology, Flow cytometry, and cytokine analysis showed that T. cp-MIF induced the dynamic polarization of THP-1 macrophages from the M1-like phenotype to the M2-like phenotype. The chemotaxis assay revealed an inhibitory effect of T. cp-MIF on THP-1 macrophages. Western blotting suggested that, compared to the control, THP-1 macrophages exposed to T. cp-MIF had higher TLR4 protein expression and the phosphatidylinositol 3'-kinase (PI3K) -Akt pathway activation. In conclusion, T. cp-MIF induces M2-like macrophage polarization through TLR4-mediated activation of the PI3K-Akt pathway, which might provide a basis for future research on how it affects the immune system of the host.

Autochthonous Thelazia callipaeda Infection in Dog, New York, USA, 2020.

We report a case of autochthonous infection of the eye worm Thelazia callipaeda in a dog in the northeastern United States. Integrated morphologic identification and molecular diagnosis confirmed the species. Phylogenetic analysis suggested introduction from Europe. The zoonotic potential of this parasite warrants broader surveillance and increased awareness among physicians and veterinarians.

Thelazia callipaeda infection during phacoemulsification cataract surgery: a case report.

BACKGROUND: In August 2020, we found one case of thelazia callipaeda infection during phacoemulsification cataract surgery. This maybe the first report for thelazia callipaeda discovered during phacoemulsification cataract surgery in China. CASE PRESENTATION: An 85 years old farmer was found thelazia callipaeda infection during phacoemulsification cataract surgery. The patient admitted whose foreign body sensation was often found in the right eye in recent 2 months. The worm was then taken out with ophthalmic forceps and put into sterile normal saline. The worm was sent to the Eye Institute of Shandong University of Traditional Chinese Medicine for identification. After identification, the worm was regarded as the male thelazia callipaeda. The head is blunt and round, the tail end curls to the abdomen, and the long copulation spines protrudes from the cloaca. The conjunctival sac was washed carefully with a large amount of Sodium Lactate Ringer 's Solution. After operation, antibiotics, pranoprofen eye drops, and tobramycin dexamethasone eye drops were further applied. After continuous examination of conjunctival sac for 2 weeks, the patient's visual acuity maintained 20/20, confirming that there was no residual thelazia. CONCLUSIONS: This report highlights the physician should ask the patient's history carefully before operation and it is necessary to strengthen health publicity and education, maintaining clean environment and keeping personal eye hygiene.

A human corneal ulcer caused by Thelazia callipaeda in Southwest China: case report.

In this study, we describe a rare human case with corneal ulcer caused by thelaziosis in a 69-year-old man in Southwest China. A male nematode was discovered and removed from the patient's right eye with a long spicule and further identified by sequencing mitochondrial cox1 gene. The ophthalmologic and molecular biological evidence demonstrates the corneal ulcer caused by T. callipaeda infection, which is mainly distributed in Asian and European countries. Most T. callipaeda infections are emerged in the conjunctiva, leading to conjunctivitis. To the best knowledge of the authors, corneal ulcers caused by T. callipaeda have not been reported yet.

Ophthalmic Thelazia callipaeda infections: first feline and new canine imported cases in Germany.

The first case of feline ocular Thelazia callipaeda infection and two new canine imported infections in West Germany are here described. The three animals had a history of recent travel to/from other countries. The young adult cat imported from Spain presented an intermittent unilateral ocular discharge. During in-depth ophthalmic examination, a single alive nematode was removed from the conjunctival compartment of the affected eye. Referring to the canine cases, an adult female dog originated from Kenya presented epiphora and mucous whitish-grey discharge of the right eye. During flushing of the nasolacrimal duct two small, thin and long nematodes were removed. Furthermore, a male Borzoi racing dog with regular visit to racing tracks in different countries presented ocular mucous discharge. At ophthalmologic examination, two transparent-whitish vital nematodes were removed. All nematode specimens of the three cases were morphologically identified as adult T. callipaeda parasites. The animals were treated orally with milbemycin oxime (2.0 mg/kg; cat) or milbemycin oxime/praziquantel (0.5 mg/kg and 5.0 mg/kg; dogs) twice with 1-week interval resulting in complete resolution of symptoms. The repeated introduction of patent T. callipaeda-infected animals, especially from southern and eastern endemic countries, will ease the establishment of ophthalmic thelaziosis in Northern Europe. The male fruit fly, Phortica variegata, an intermediate host of T. callipaeda, is endemic within European countries. Considering the clinical and zoonotic relevance of ophthalmic thelaziosis, enhanced disease awareness of European medical and veterinarian doctors and in-depth eye examination for proper detection of T. callipaeda are crucial for appropriate anthelmintic treatments and to limit spreading of the infection.

Suspected autochthonous Thelazia callipaeda infection in a dog in northern Germany.

A 12-year old Elo dog was presented with recurring symptoms of conjunctivitis in November 2019. A single whitish nematode was found upon inspection of the eye and identified as a Thelazia callipaeda male. The morphological identification of the eye worm was supported by analysis of a partial cytochrome c oxidase I (cox1) gene sequence. The dog lived in Lower Saxony, northwestern Germany, and had not visited regions known to be endemic for T. callipaeda. This suggests that a local transmission cycle of this zoonotic nematode may exist in Germany.

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.

The first autochthonous case of feline ocular thelaziosis in Austria.

Over the last 30 years, Thelazia callipaeda (Spirurida: Thelaziidae) has increasingly been reported as an agent of ocular infections in animals and humans throughout Europe. Following the cases of canine ocular thelaziosis recently recorded in Austria for the first time, in the present paper, we describe the first case of T. callipaeda infection in an Austrian cat with no history of traveling abroad. This finding further supports the occurrence of the parasite's autochthonous transmission cycle in the country. The cat showed serous ocular discharge, conjunctival hyperemia, and mild conjunctival edema in the right eye. Mechanical removal of the parasite from the cat's eye, in combination with milbemycin oxime/praziquantel oral treatment and topical use of tobramycin/dexamethasone eye drops led to complete resolution of the clinical signs within 2 weeks. Results presented in the current study are of great importance for the local veterinarians who seemed largely unaware of this zoonotic parasite. Therefore, increased awareness of medical and veterinary communities is imperative for preventing further infections in both animals and humans.

Ocular thelaziosis due Thelazia callipaeda (Spirurida: Thelaziidae) in Romania: first report in domestic cat and new geographical records of canine cases.

Thelazia callipaeda has been regarded in Europe in the last few decades as a "new" agent of an ocular disease in dogs, cats, several wild species, and not least in humans. After the first European description in Italy, in 1989, the parasite has been reported in many other countries, showing a widespread distribution of this parasite. The first case of canine thelaziosis in Romania has been reported in 2015, and it has been followed by other studies confirming the presence of the nematode in dogs or broadening the host spectrum with some wild carnivore species that have been found positive. Despite being considered suitable primary hosts for T. callipaeda, infection with T. callipaeda in domestic cat is rarely reported in Europe, probably due to some behavioral and physical particularities of this host. This study describes the first autochthonous report of T. callipaeda infection in a domestic cat from Romania. Additionally, to these findings, new geographical records of canine thelaziosis are being revealed, confirming the increased risk of this emerging vector-borne zoonosis.

Thelazia callipaeda infection in a 5-month-old infant.

BACKGROUND: Thelazia callipaeda is the main causative organism in thelaziasis, commonly infecting orbital cavities and associated tissues of carnivores. Thelazia callipaeda infection is rarely reported in humans, especially in infants. CASE PRESENTATION: A 5-month-old male infant presented with 2 weeks of redness and increased secretions in the left eye. On examination, the left eye revealed the presence of one creamy thread-like mobile worm in the conjunctival sac. During surgical exploration, a total of 11 worms were extracted from the left eye. The worms were morphologically identified as seven female and four male T. callipaeda. Ocular symptoms resolved rapidly after the removal of the worms, with no recurrence after the 6-month follow-up. CONCLUSION: We present here detailed clinical and morphological information pertaining to T. callipaeda infection, which is considered to be a probably neglected parasitic disease of the eye. This case illustrates the importance of including thelaziasis into the differential diagnosis of ocular surface diseases, especially in infant patients.

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.

New host record of Thelazia callipaeda (Nematoda: Spirurida) with a notably wide host range and shared zoonotic lineage in Japan.

Thelazia callipaeda (Nematoda: Spirurida: Thelaziidae) parasitizes the eyes of dogs, cats, humans, and various wild mammals, and is transmitted by drosophilid flies. In Japan, T. callipaeda is considered an emerging parasite that has expanded its endemic region northward. However, reports of its detection in mammals other than domestic animals and humans are scarce. This study reports the detection of T. callipaeda in Japanese red fox (Vulpes vulpes japonica), masked palm civet (Paguma larvata), Japanese badger (Meles anakuma), Japanese black bear (Ursus thibetanus japonicus), raccoon (Procyon lotor), Japanese raccoon dog (Nyctereutes viverrinus), domestic dog (Canis lupus familiaris), domestic cat (Felis silvestris catus), and human. Of these, the Japanese red fox, masked palm civet, Japanese badger, and Japanese black bear have been reported as novel host records. Sequence analysis of the cytochrome c oxidase subunit I gene of T. callipaeda revealed two unique lineages specific to Japan, with no regional or host species differences. These results suggest a wide host range for T. callipaeda, highlighting the significant role of wildlife as a reservoir for this parasite in Japan.

Efficacy of a combination of esafoxolaner, eprinomectin and praziquantel (NexGard® Combo) against Thelazia callipaeda in naturally infected cats.

This clinical study assessed the efficacy of a topical combination of esafoxolaner, eprinomectin and praziquantel (NexGard® Combo) in treating cats naturally infected with the eyeworm Thelazia callipaeda (Nematoda, Thelaziidae). On Study Day (SD) 0, sixteen client-owned cats with eyeworm infection were allocated to an untreated control group (G1, 8 cats) or to a NexGard® Combo treated group (G2, 8 cats) and subjected to ocular examination. Cats in G2 received the treatment as per label recommendations. On SD 7 and 14 (±1), cats were examined for the presence of eyeworms and clinical signs. On SD 14, eyeworms were collected and counted. On SD 7 and 14, all cats in G1 were still infected with eyeworms, while G2 cats were free from eyeworms on SD 7 and 14, demonstrating 100% efficacy (p < 0.0001). All collected eyeworms were morphologically and molecularly confirmed to be T. callipaeda. On SD 0, fifteen out of the sixteen cats (7 in G1 and 8 in G2) displayed inflammatory ocular signs. On SD 7, all eight untreated cats and seven treated cats displayed inflammatory ocular signs. On SD 14, five out of eight G2 treated cats had recovered, while the eight untreated cats still displayed inflammatory ocular signs. The treatment significantly reduced lacrimation and conjunctivitis (p = 0.0001). No adverse reactions occurred. This clinical study provides evidence that NexGard® Combo is highly safe and effective for the treatment of T. callipaeda infection in cats under field conditions.

Title: Efficacité d'une association d'esafoxolaner, d'éprinomectine et de praziquantel (NexGard® Combo) contre Thelazia callipaeda chez le chat naturellement infecté. Abstract: Cette étude clinique a évalué l'efficacité d'une association topique d'esafoxolaner, d'éprinomectine et de praziquantel (NexGard® Combo) dans le traitement des chats naturellement infectés par le ver oculaire Thelazia callipaeda (Nematoda, Thelaziidae). Au jour d'étude (JE) 0, seize chats appartenant à des clients et atteints d'une infection par le ver oculaire ont été attribués à un groupe témoin non traité (G1, 8 chats) ou à un groupe traité NexGard® Combo (G2, 8 chats) et soumis à un examen oculaire. Les chats du groupe G2 ont reçu le traitement conformément aux recommandations de l'étiquette. Aux JE 7 et 14 (±1), les chats ont été examinés pour détecter la présence de vers oculaires et de signes cliniques. Au JE 14, les vers oculaires ont été collectés et comptés. Aux JE 7 et 14, tous les chats du G1 étaient toujours infectés par des vers oculaires, tandis que les chats du G2 étaient exempts de vers oculaires aux JE 7 et 14, démontrant une efficacité de 100 % (p < 0,0001). Tous les vers oculaires collectés ont été confirmés morphologiquement et moléculairement comme étant T. callipaeda. Au JE 0, quinze chats sur seize (7 en G1 et 8 en G2) présentaient des signes oculaires inflammatoires. Au JE 7, les huit chats non traités et les sept chats traités présentaient des signes oculaires inflammatoires. Au JE 14, cinq des huit chats traités par G2 s'étaient rétablis tandis que les huit chats non traités présentaient toujours des signes oculaires inflammatoires. Le traitement a réduit de manière significative le larmoiement et la conjonctivite (p = 0,0001). Aucun effet indésirable n'est survenu. Cette étude clinique indique que NexGard® Combo est hautement sûr et efficace pour le traitement de l'infection à T. callipaeda chez les chats dans des conditions de terrain.

The C/EBPß-SESN2 Axis Promotes M2b Macrophage Polarization Induced by T.cp-MIF to Suppress Inflammation in Thelazia Callipaeda Infection.

Infection by the conjunctival sucking nematode Thelazia callipaeda results in ocular inflammation and immune impairment. T.cp-MIF, a macrophage migration inhibitor factor of T. callipaeda, can induce macrophage polarization and is involved in the host innate immune response, but little is known about the regulatory mechanisms and the actual immune effect. Understanding the immunoregulatory mechanisms carries significant clinical relevance for the development of novel preventative and therapeutic strategies. The macrophages were induced by T.cp-MIF in vitro, and the polarization direction at different times and the expression of inflammatory factors were detected by flow cytometry analysis, qPCR and western blotting. The key transcription factors and target genes were screened through transcriptome data, and the functions of transcription factors were verified by inhibition experiments in vitro. T.cp-MIF and T. callipaeda adult worms can cause inflammation of the ocular conjunctiva and macrophage infiltration. T.cp-MIF activated macrophages presenting M2b polarization after 48 h and played a role in inhibiting inflammation. Furthermore, based on the results of transcriptome data analysis and inhibition experiments, we demonstrate that this polarization is dependent on the involvement of the transcription factor C/EBPß and its target gene SESN2. Our results demonstrated that the C/EBPß-SESN2 axis plays an important regulatory role in T.cp-MIF-induced macrophage M2b polarization and it provides a new perspective for understanding the immune escape of ocular parasite infection.

The species and abundance of gut bacteria both positively impact Phortica okadai behavior.

BACKGROUND: Gut bacteria, which serve as essential modulators, exert a significant impact on insect physiology and behavior and have substantial application potential in pest management. The dynamics of gut bacteria and their impact on Phortica okadai behavior remain unclear. METHODS: In this study, the dynamics of gut bacteria at different developmental stages in P. okadai were analyzed using 16S ribosomal RNA (rRNA) gene sequencing, and the species and abundance of gut bacteria that affect host behavior were examined via behavioral experiments. RESULTS: A total of 19 phyla, 29 classes, 74 orders, 101 species, and 169 genera were identified. The results of the behavioral experiments indicated that the species Lactiplantibacillus argentoratensis, Acetobacter tropicalis, Leuconostoc citreum, and Levilactobacillus brevis effectively influenced the feeding preference of P. okadai, and the single-bacterium-seeded P. okadai exhibited feeding preferences distinct from those of the germ-free (GF) and wild-type P. okadai. CONCLUSIONS: The species and relative abundance of gut bacteria together positively impact P. okadai behavior. Lactiplantibacillus argentoratensis, as the most attractive bacteria to P. okadai, presents opportunities for novel pest control strategies targeting this vector and agricultural pest.

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.

Human ocular thelaziasis with genetic analysis in Niigata Prefecture, Japan: A case report on an emerging zoonosis.

Purpose: We report the clinical findings and molecular identification of ocular Thelazia callipaeda from Niigata Prefecture in the Hokuriku area of Japan during winter. Observations: A 77-year-old male visited an ophthalmology clinic in Niigata Prefecture in January 2022 after a 2-week-duration of a conjunctival injection in the left eye and foreign body sensation. Slit-lamp microscopy revealed 11 active nematodes in the left conjunctival sac. Morphological characteristics included longer female body length than male, buccal cavity lacking teeth and lips, and serrated striations along the body surface. The specimens were determined to be T. callipaeda. Genetic analysis of the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene revealed an h9 haplotype. Conclusions and Importance: T. callipaeda infection, especially the h9 haplotype, commonly occurs in western Japan owing to its higher incidence in warmer climates, suggesting the origin of the case. Here, we report a human case of Thelaziasis diagnosed in a cold region of Japan (the Hokuriku area) during winter. This human case of T. callipaeda infection from a cold, previously unassociated region, raises concerns about the potential geographical widening of its distribution, and further investigation may be warranted to prevent its spread.