Rabbit-derived human Thelazia callipaeda infection: a case report.

In November 2021, a 19-year-old medical student was diagnosed with a rabbit-derived Thelazia callipaeda infection in her left eye. She visited her doctor because she removed the white object by herself with a cotton swab 2 days earlier. She explained to the doctor that she rubbed her eyes without washing her hands when rabbit hair got into her eyes during the animal experiment class at school 2 weeks earlier. The other 2 worms were then taken out with ophthalmic forceps and were placed into physiological saline. The worms were sent to the Shandong Academy of Eye Disease Prevention and Therapy for examination. After identification, the worms were regarded as the female T. callipaeda. Ofloxacin eye drops and peranapulin eye drops were administered to control inflammation. No abnormality was found in the follow-up 2 weeks and 1 month later. This report highlights that it is very important to strengthen the health and safety education of medical students during animal experiment classes.

The occurrence and clinical importance of infectious stage of Echinocephalus (Nematoda: Gnathostomidae) larvae in selected Australian edible fish.

Cases of gnathostomiasis, an infection caused by consuming infected seafood, have been reported in Australia. However, doubt exists over the validity of these diagnoses as there are no reports of Gnathostoma spp. in Australian teleost fish. Also, the diagnoses in human cases were based on a serological test developed in Thailand. The specificity and sensitivity of this test in non-endemic areas are uncertain. Interestingly, parasites belonging to the genus Echinocephalus, which morphologically are very similar to Gnathostomum, are commonly found in Australian fish and shellfish and can potentially infect humans. The aim of this study was to determine the occurrence of these zoonotic nematodes within commercial fish and to characterise nematode larvae in order to provide insights into the specific identity of the potential causative agents of gnathostomiasis in Australia. Six edible fish species (n = 163) were examined. Gnathostomid-type larvae were found only in Acanthopagrus australis and Rhabdosargus sarba. Detailed examination and sequence data suggested parasite larvae belonged to the genus Echinocephalus. Further investigation of the occurrence of zoonotic nematodes within marine environments and observation of their spatial and temporal patterns will help raise awareness of the significance of this food safety issue within global fishing industries and health sectors. The accurate identification of zoonotic nematodes is a key component of disease surveillance and control. This information can also be used to develop specific and sensitive diagnostic test.

Thelazia rhodesi in a dairy farm in Romania and successful treatment using eprinomectin.

Bovine thelaziosis can be caused by Thelazia rhodesi Desmarest 1828, Thelazia gulosa Railliet & Henry 1910 and Thelazia skrjabini Erschow 1928 which are known to be transmitted by species of Muscidae. Therapeutic measures in cattle include mechanical removal of the adult parasites, followed by irrigation of the conjunctival sac with different solutions such as levamisole (1%) or administration of ivermectin (0.2 mg/kg SC), doramectin (0.2 mg/kg SC or pour-on) both with high efficacy, however, the use of such macrocyclic lactones can be problematic in lactating cattle. Nematodes harboured in the eyes of some cattle from Romania were morphologically identified as Thelazia rhodesi and the PCR analysis confirmed the diagnosis with a 98.0% nucleotide similarity for ITS1 sequence, with other sequences available in GenBank. The present paper reports the presence of T. rhodesi in cattle from a dairy farm in Romania and the recovery after treatment with eprinomectin. To the best of our knowledge this is the first report on the efficacy of eprinomectin against Thelazia spp. and the first molecular confirmation of T. rhodesi in Romania.

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.

Phthiriasis palpebrarum, thelaziasis, and ophthalmomyiasis.

INTRODUCTION: Parasitic infections of the eye are a major cause of ocular-surface diseases globally. While most infections are treatable, parasites can cause varying levels of damage mostly due to late diagnosis or misdiagnosis as a result of doctors' unfamiliarity with their characteristics of latency and crypsis, as well as lack of awareness by the patients. CASE REPORTS: In this study, we present three cases of phthiriasis palpebrarum, thelaziasis, and ophthalmomyiasis, respectively. Two of the cases were treated at the clinic and did not recur. One patient refused treatment and was lost to follow-up. DISCUSSION: By evaluating the natural histories, morphology, symptoms, clinical findings, and treatment of these parasitic diseases, we systematically analyzed several distinct and unique parasite characteristics, especially latency and crypsis. Furthermore, we have proposed specific examination techniques and methods as well as prevention and treatment strategies from these specific perspectives, aiming to prompt timely diagnoses and early interventions for these diseases by health care workers and improve the public's awareness of parasitic infections. CONCLUSION: Parasitosis on the ocular surface is a global infectious disease, and prevention strategies include maintaining personal and environmental hygiene and limiting contact with animals. We recommend that health care workers should enhance their ability to detect and diagnose these diseases while promoting the public's awareness of them in the context of our new perspectives.

Canine thelaziosis in the Czech Republic: the northernmost autochthonous occurrence of the eye nematode Thelazia callipaeda Railliet et Henry, 1910 in Europe.

The eye nematode Thelazia callipaeda Railliet et Henry, 1910 (Spirurida: Thelaziidae) is a vector-borne zoonotic nematode infecting a range of wild and domestic carnivores as well as humans. It is considered to be a causative agent of emerging and neglected disease and currently invades central part of Europe. Nematodes were collected from the eye of a dog living in Prague, which never travelled outside the Czech Republic. The nematodes were identified based on their morphology and partial sequence of the cox1 gene as T. callipaeda haplotype 1. This finding represents the northernmost record of autochthonous canine thelaziosis in Europe. The insufficient control of imported animals as well as free movement of dogs and wild carnivores within Europe probably facilitates spreading of T. callipaeda throughout the continent. To better understand the spreading of T. callipaeda and to prevent its zoonotic transmissions, information about the risk of this infection in newly invaded countries should be disseminated not only among veterinarians and physicians, but also within the community of pet owners and hunters.

Temperature is a common climatic descriptor of lachryphagous activity period in Phortica variegata (Diptera: Drosophilidae) from multiple geographical locations.

BACKGROUND: The drosophilid Phortica variegata is known as vector of Thelazia callipaeda, the oriental eyeworm native to Asia that has become an emergent zoonotic agent in several European regions. Unlike almost all other arthropod vectors of pathogens, only P. variegata males feed of lachrymal secretions of animals, ingesting first-stage larvae (L1) of the worm living in the orbital cavities of the host, and allowing with the same behaviour the introduction of infective L3. Despite the increased detection of T. callipaeda in many European countries, information about the length of the lachryphagous activity period of P. variegata and a deep knowledge of the environmental and climatic variables involved are still limited. METHODS: We herein present the results of a multicentre study involving five sites from four different countries (Italy, Spain, UK and USA) where canine thelaziosis is endemic and/or where it has already been ascertained the presence of P. variegata. Field data have been obtained on a fortnightly basis from mid-April to the end of November 2018 from a contemporary standardized sampling (same sampling effort and time of collection in all sites) of lachryphagous flies collected around the eyes of a human bait using an entomological net. These data have been associated to data collection of local climatic variables (day length, temperature, wind speed, barometric pressure and relative humidity). RESULTS: Overall, a total of 4862 P. variegata flies (4637 males and 224 females) were collected, with high differences in densities among the different sampling sites. Significant positive correlations were found between P. variegata male density and temperature and wind speed, while negative correlations were observed for barometric pressure and relative humidity. However, the above significant differences are confirmed in each sampling site separately only for the temperature. CONCLUSIONS: This multicentre study highlights that temperature is the major common environmental driver in describing the lachryphagous activity of P. variegata in Europe and USA and, therefore, the transmission risk of thelaziosis.

Spain as a dispersion model for Thelazia callipaeda eyeworm in dogs in Europe.

Thelazia callipaeda (Spirurida, Thelaziidae) causes ocular infection in carnivorous animals and humans. While growing numbers of companion dogs and sometimes cats are being diagnosed with thelaziosis, little is known about its real spread. As it has been also diagnosed in wild animals and human beings, it is considered a potential emerging zoonotic disease. This study provides information about the spread of the parasite in dogs in Spain since its initial description in 2010 until 2018. The first detection of T. callipaeda in the Principality of Andorra in 2017 is also reported. Two different studies were conducted: a) a survey in which clinical cases from veterinary practices were collected and b) a prevalence study in two endemic areas in western and central Spain (Site 1 La Vera region, Cáceres, and Site 2 El Escorial municipality, Madrid). In total, 1114 cases of thelaziosis were detected in 121 municipalities of Spain and 6 municipalities of Andorra. In 92 out these 127 municipalities, reports were of autochthonous cases. Six hundred twenty-three out of 1114 presented data collection sheet and were included in the statistical analysis: 510 cases identified by veterinarians in Spain and Andorra in Study 1, and 113 cases detected among the 234 dogs (48.3 %) examined in the prevalence study (Study 2). Prevalences were 61.3 % (84/137) for Cáceres and 29.9 % (29/97) for Madrid, being Site 1 significantly more risky (P <  0.0001, odds ratio: 3.72, CI: 2.14-4.47 %) compared to Site 2. Our study updates data for canine thelaziosis reported in the last decade in Spain and Andorra. Results highlight the urgent need for prevention strategies to control the spread of this potential zoonotic 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 epidemiological data on Spirocerca vulpis in the red fox: A parasite of clustered geographical distribution.

This is the first study describing the epidemiology of Spirocerca vulpis after its description as a new species in 2018. During the period 2006-2013, a total of 286 red foxes (Vulpes vulpes) from the Valencian Community (southeast Spain) were necropsied. Based on data collected, S. vulpis prevalence and intensity were calculated, as well as the spatial distribution of this nematode. Influence of host (sex and age) and environmental factors on S. vulpis occurrence was evaluated. MAXENT software was used to model and predict the parasite distribution. Continuous and discrete prediction maps were built using ArcMap 10.6. The prevalence of S. vulpis was 22% (63/286; 95% CI: 17.4-27.3), and the median intensity was 5 (IQR 11) nematode specimens. No significant difference in term of intensity was found between males and females; regarding the host age, S. vulpis was found only in adult foxes, with the exception of one juvenile individual. The distribution of S. vulpis in foxes was skewed to the left, highlighting that parasite infection affects few individuals within a population, with parasitized animals being responsible to maintain the infection at the population level. The majority of parasitized foxes had a parasite burden lower than eight parasites/individual. S. vulpis distribution in Valencian Community presents sharply defined areas in which there are optimal environmental conditions for maintaining the life cycle of this parasite. Climatic variables and altitude are the main factors influencing the parasite presence. Our results indicate that S. vulpis has epidemiological characteristics similar to those of S. lupi and, therefore, based on the phylogenetic proximity of both nematode species, it is likely that coprophagous beetle species might play a key epidemiological role in the maintenance of this newly described Spirocerca species. Moreover, it is currently unknown if S. vulpis can infect the dog and other wild canid species apart from the red fox and, if so, what are the pathogenic effects on these host species. Therefore, it is necessary to continue investigating the epidemiology of this parasite in order to know the range of appropriate host species. This information will enable to know if S. vulpis endemic areas should be considered as health risk points for dogs, especially for the most exposed, such as those living in rural areas, and hunting dogs.

Thelazia callipaeda in mustelids from Romania with the European badger, Meles meles, as a new host for this parasite.

BACKGROUND: Thelazia callipaeda (Spirurida, Thelaziidae) is a vector-borne zoonotic eye worm with a broad host spectrum. In Europe, it is an emerging threat, having greatly expanded its geographical distribution during the past two decades. In Romania, T. callipaeda has been previously reported in domestic and wild canids and felids. The aim of the present study was to assess the occurrence of T. callipaeda in mustelids in the country. METHODS: Between March 2015 and April 2019, 77 road-killed mustelids (3 pine martens, Martes martes; 6 European polecats, Mustela putorius; 13 beech martens, Martes foina; and 55 European badgers, Meles meles) were examined by necropsy. If present, all ocular nematodes were collected and stored in absolute ethanol, for subsequent morphological and molecular identification. RESULTS: Two animals were found to be infected with T. callipaeda: one European badger and one beech marten. The molecular analysis revealed a 100% nucleotide similarity to T. callipaeda haplotype h1 for all the sequenced specimens. CONCLUSIONS: To our knowledge, the present study demonstrates for the first time the occurrence of T. callipaeda in mustelids from Romania, records the easternmost locality of the parasite in Europe, and represents the first report of T. callipaeda in the European badger, Meles meles, extending the known host range for this parasite in Europe.

Rhabdochona angusticaudata sp. n. (Nematoda: Rhabdochonidae) from the Japanese eel Anguilla japonica, and new records of some other nematodes from inland fishes in Japan.

Collections of parasitic nematodes of fishes from some freshwater and brackish-water localities in Honshu, Shikoku and Hokkaido, Japan, carried out in 1996-2009, yielded the following eight species: Hysterothylacium haze (Machida, Takahashi et Masuuchi, 1978) (Anisakidae), Paraquimperia sp., Pingus sinensis Hsü, 1933 (both Quimperiidae), Heliconema anguillae Yamaguti, 1935 (Physalopteridae), Rhabdochona angusticaudata sp. n., Rhabdochona zacconis Yamaguti, 1935 (both Rhabdochonidae), Ascarophis arctica Polyanskiy, 1952 (Cystidicolidae) and Eustrongylides sp. larvae (Dioctophymatidae). The new species, R. angusticaudata sp. n., described from the intestine of the Japanese eel Anguilla japonica Temminck et Schlegel in the Renjoji River, Shikoku, is mainly characterised by the presence of 14-16 anterior prostomal teeth, non-bifurcated deirids with rounded ends, the length of the left spicule (300-384 µm long), the right spicule with a dorsal barb and non-filamented eggs. The species of Paraquimperia Baylis, 1934 and A. arctica are reported from Japan for the first time. Based on light and scanning electron microscopical examinations, some new morphological data on H. haze, H. anguillae, R. zacconis and A. arctica are provided.

Population genetic structure of the parasitic nematode Spirocerca lupi in South Africa.

Spirocerca lupi is a parasitic nematode of canids and occurs in most tropical and subtropical regions around the world. While its life cycle is well known, insight is lacking about its mating structure within-hosts, genetic variability and long-distance dispersal ability. These characteristics contribute significantly to the dynamics and spread of potential resistance genes, which impacts on the control of S. lupi. To evaluate the population structure and infer potential mating behaviour of S. lupi, we genotyped 130 samples at nine microsatellite loci from three geographical locations in South Africa, between 600 and 1000 km apart. These loci identified unique individuals with high levels of polymorphism suggesting that these are not newly established S. lupi populations in South Africa and that effective population sizes must be large. Population genetic analyses showed that populations are not very distinct, that worms within dogs are more similar to each other than random worms from each population, and that mating is at random within dogs. We can thus infer that the parasite is frequently transported over great distances. Even so, two genetically distinct populations could be identified. Relatedness of worms within dogs were significantly higher than between dogs and together with F-statistics suggests some non-random transmission of parasites between hosts. While mating is random within a host, parasites from a host are more likely to be related and hence an increase in homozygosity is seen. The implications of this genetic structure on parasite control are considered.

The first feline and new canine cases of Thelazia callipaeda (Spirurida: Thelaziidae) infection in Hungary.

BACKGROUND: In Europe, the first Thelazia callipaeda infections were found in the eyes of some dogs in Italy three decades ago. Since that time, this vector-borne nematode species has been diagnosed in domestic and wild carnivores and humans in some western European countries. During the last few years, autochthonous thelaziosis of dogs, red foxes, cats and humans has also been reported from eastern Europe. The first cases of ocular infections caused by T. callipaeda have been described in dogs living in the eastern and southern part of Slovakia and Hungary. METHODS: Whitish parasites found in the conjuctival sac and/or under the third eyelid of one or both eyes of animals were removed and morphologically identified according to species and sex. To confirm the morphological identification with molecular analysis a single step conventional PCR was carried out. RESULTS: A total of 116 adult worms (1-37 per dog, median: 7, IQR: 14.5 and 7 from a cat) were collected from the eyes of 11 animals. Nematodes were identified as T. callipaeda according to the morphological keys and molecular analysis. The sequences of a portion of the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene were identical to those representing T. callipaeda haplotype 1, previously reported in neighbouring and other European countries. Since the infected cat and dogs had never travelled abroad, all of the cases were autochthonous thelaziosis. CONCLUSIONS: The present study reports the first case of thelaziosis in a cat and new cases in 10 dogs found in the southern and northern region of Hungary, respectively. Further studies are needed to clarify whether wild carnivores (e.g. red foxes, golden jackals) may act as reservoirs of this eyeworm species in the country.

Predicting the distribution of Phortica variegata and potential for Thelazia callipaeda transmission in Europe and the United Kingdom.

BACKGROUND: Male fruitflies Phortica variegata (Drosophilidae, Steganinae) are the intermediate host of the zoonotic nematode Thelazia callipaeda (Spirurida, Thelaziidae). More than 10 years ago, when T. callipaeda was confined to remote regions of southern Italy, ecological niche models were used to predict the potential distribution of P. variegata across Europe and the likely risk of the nematode spreading through infected dogs travelling to/from endemic regions. As predicted, over the last 10 years T. callipaeda has spread rapidly across Europe. Recently, we identified the potential for its introduction to the UK through infected dogs travelling to/from endemic regions of mainland Europe. METHODS: Here updated information is used to re-evaluate the model-predicted European, and specifically, UK distribution to determine the likelihood of T. callipaeda becoming established. Additionally, the UK distribution of P. variegata was further investigated through snapshot fly trapping at model-predicted locations. RESULTS: Ecological niche modelling using Genetic Algorithm for Rule-set Prediction (GARP) analysis suggests a European range similar to that described previously, with some indication of potential spread further eastward. Finer scale UK mapping suggested that P. variegata presence was limited mostly to southern England, but highlighted regions where P. variegata has not been documented previously. The arbitrary fly trapping identified activity of P. variegata at two locations where the species has been found previously late in the season. No specimens were collected at model-predicted locations, although habitat suitable for the species was identified. CONCLUSIONS: GARP-model prediction of P. variegata distribution suggests presence of suitable conditions in previously undocumented regions of the UK and Europe and highlight the possibility for further spread of T. callipaeda across Europe, including the UK. Further work to validate the P. variegata UK model with field data will help improve its accuracy in predicting suitable areas, whilst surveillance of sylvatic definitive host species in such locations is advised to monitor for evidence of autochthonous T. callipaeda transmission.

Questionnaire-based survey on distribution of canine ocular thelaziosis in southwestern France.

The distribution of Thelazia callipaeda, commonly known as "oriental eyeworm'', has been considered for a long time to be confined to the former soviet Republics and Asia where the nematode causes infections in domestic and wild carnivores, rabbits and sometimes humans. However, since 2000, thelaziosis has been diagnosed in dogs and sometimes in cats from a growing number of European countries, including France. In 2006, a survey demonstrated that many autochthonous cases of canine thelaziosis were present in the department of Dordogne (southwestern France) in three hyperenzootic counties where strawberry production was predominant. The objective of the present study was to obtain an updated evaluation of the enzootic occurrence of T. callipaeda in France. In April 2016, an electronic questionnaire was sent to 1670 veterinary clinics from 24 French departments of southwestern France. Among 279 responses, 97 veterinary clinics reported cases of canine thelaziosis during the last 12 months. Most of them (72/97, 74.2%) reported a limited number of cases. Two veterinary clinics in previously-identified hyperenzootic counties of Dordogne reported the higher incidence (50 and 68 new cases annually). Noteworthly, two clinics located in another department (Landes) also reported many autochthonous cases (30 cases annually) demonstrating the existence of new enzootic foci. The present investigation confirmed that Dordogne is still an enzootic area of ocular thelaziosis and that the disease is spreading in new areas of southwestern France since a decade.

The eyeworm Thelazia callipaeda in Portugal: Current status of infection in pets and wild mammals and case report in a beech marten (Martes foina).

Ocular thelaziosis is caused by nematodes of the genus Thelazia (Spirurida, Thelaziidae), which inhabit the surface of the eyes and associated tissues. Thelazia callipaeda affects a range of mammal species, including humans, and in the last two decades has been reported in multiple European countries, being classified as an emergent vector-borne pathogen. In Portugal T. callipaeda is endemic in north-eastern areas, where it has been reported in domestic dogs, cats, red foxes (Vulpes vulpes) and wild European rabbits (Oryctolagus cuniculus). We report, for the first time, T. callipaeda in a beech marten (Martes foina) from Portugal and highlight the presence of haplotype 1 as the only one found in Europe, irrespective of the host species and geographical area of provenience.

Influence of physical and chemical factors on the embryonation, hatching and infectivity of Spirocerca lupi.

Spirocerca lupi is a parasitic nematode which causes spirocercosis, a severe disease of dogs. Its life cycle involves dung beetles as intermediate hosts and canids as definitive hosts. The effect of different physical conditions and chemical factors on the embryonation and hatching of S. lupi eggs were investigated in this study in order to understand the triggers for progression in the early development of this parasite. Exposure to potassium dichromate significantly enhanced the embryonation of eggs compared to formaldehyde and controls (p<0.0001), reaching the maximum embryonation level of 83% within 2days of incubation. Hatching of eggs was significantly (p<0.05) enhanced in the presence of 2.5% trypsin, pH 6.0 and 8.0, a temperature of 26°C, 20% CO2 and mechanical force by stirring with 3-mm beads. Dissection of Onthophagus sellatus beetles 8h post-feeding with eggs showed that 13% of the ingested eggs hatched in the buccal cavity and the midgut. Finally, the pH range of the beetle's gut was 6.0-6.2 compared to 7.2±0.4 in dog feces suggesting that this pH change may induce hatching in the beetle. These findings contribute to the understanding of the early steps in the life cycle of S. lupi and may be used in the future to block the development of S. lupi and prevent dog infection and disease.

Transmission of the eyeworm Thelazia callipaeda: between fantasy and reality.

BACKGROUND: Thelazia callipaeda is transmitted by Phortica variegata, a drosophilid that feeds on lachrymal secretions of mammals. Scientific information on human thelaziosis is still relatively limited, mainly for physicians and ophthalmologists. Indeed, the literature is full of misleading information on the transmission of T. callipaeda to humans. FINDINGS: A recent paper reported a case of human intraocular infestation in a patient from Karnataka. The information presented in that article as well as in other articles in the international literature is outdated and incorrect in several instances, mostly regarding to the localization of T. callipaeda in the host, its biology and routes of transmission. CONCLUSIONS: Physicians and ophthalmologists should be aware that T. callipaeda is larviparous and transmitted exclusively by secretophagous flies. These flies buzz around the eyes of animals and humans at the daytime, landing on the eyes and releasing the infective larvae on the host conjunctiva. That is the only possible way of transmission of T. callipaeda.