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Purpose: Human ophthalmomyiasis is a rare ocular parasitosis that results from the accidental infestation of dipteran larvae of several species, including Oestrus ovis (Linnaeus, 1758). This study aims to present the fourth documented human case of ophthalmomyiasis in Mexico, identifying the etiological agent through morphological and molecular analyses. Additionally, we investigated the phylogenetic position and genetic distances among different specimens globally characterized based on mitochondrial Cox1 sequences., Methods: A total of five larval specimens were extracted from the patient's eye, with two specimens allocated for identification based on morphological features using a stereomicroscope, and the remaining three preserved in absolute ethanol, one of them used for subsequent analysis using molecular methods. The mitochondrial Cox1 region was amplified and sequenced using automated Sanger sequencing. The resulting sequence was deposited in GenBank under accession number OR440699 and subjected to BlastN analysis against 35 other Cox1 sequences of O. ovis from GenBank. The identity and phylogenetic position of the strains were further explored using parsimony and maximum likelihood phylogenetic methods., Results: Morphological examination of the larval specimens extracted from the patient's eye unequivocally identified them as O. ovis species. BlastN analysis and comprehensive phylogenetic investigations involving a total of 36 Cox1 sequences confirmed the taxonomic identity of the larvae. Notably, our sequence was positioned within the cluster formed by the Brazilian and two Iranian samples. This finding underscores a shared genetic ancestry among these distinct geographical isolates and provides valuable insights into the evolutionary relationships within O. ovis populations., Conclusion: The presence of O. ovis infestation in Mexico City suggests potential shifts in environmental conditions favoring fly proliferation, highlighting the need for vigilance in urban healthcare settings., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

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., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Case Series Summary: Described are four cats diagnosed with ophthalmomyiasis externa caused by Cuterebra larvae. Medical records were retrospectively reviewed to identify cats with ophthalmomyiasis externa between 2005 and 2020 at Cornell University Hospital for Animals. Signalment, history, clinical and diagnostic findings, treatment and outcome were recorded. All cats were young (< 3 years of age), had outdoor access and were initially examined during the summer months. All cases had unilateral disease with the right eye affected. Two cases had nictitating membrane lesions and two had orbital disease. Concurrent superficial corneal ulceration was present in three cats. Two cats suffered from pyrexia, suspected secondary to inflammation from the larval infestation. Successful larval removal was performed in all cats, which resulted in improvement of discomfort and clinical signs. A corneal ulcer persisted in one cat, which was lost to follow-up prior to ulcer resolution. Parasite identification confirmed Cuterebra species infestation in all cases., Relevance and Novel Information: To the authors' knowledge, this is the first report of feline ophthalmomyiasis externa caused by Cuterebra species. Parasite removal was successful in restoring comfort and resolving clinical signs in all cats with adequate follow-up information.

Thelazia callipaeda is a vector borne zoonotic nematode transmitted by drosophilid flies of Phortica genus. It has been reported in humans from different parts of India including North Eastern region. Only one case of canine ocular thelaziosis has been reported from southern India while no case has yet been reported from the rest of the country. This communication reports the first case of canine ocular thelaziosis from Nagaland and the entire North East region of India along with the morphological characters and treatment., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Purpose: Ocular toxocariasis (OT) is a zoonotic infection caused by larval stages of Toxocara canis and T. cati . The current review and meta-analysis aimed to evaluate the global prevalence of OT., Methods: Five English (PubMed, Scopus, Science Direct, Web of Science, and Google Scholar) databases were explored and 101 articles met the inclusion criteria., Results: The pooled prevalence (95% confidence interval) of OT was higher in immunological studies (9%. 6-12%) than in studies that applied ophthalmic examination (1%. 1-2%). The lower middle-income level countries had the highest prevalence (6%. 2-12%) as well as the African region (10%. 7-13%). The highest infection rate (4%. 2-7%) was detected in the 1-25 mean age group., Conclusion: Regular anthelminthic treatment of cats and dogs, and removal of animal feces from public places must be considered.

Parasitism is one of the most common consumer strategies and contributes a large portion to biological diversity. Trematodes in the family Diplostomidae are common in freshwater ecosystems worldwide, often residing in the eyes or brain of fish and then infecting fish-eating birds as adults. As a result, some species have broad geographic distributions due to the bird host's motility. In contrast to the cosmopolitan nature of diplostomids, only a single species, Tylodelphys darbyi, has been identified in New Zealand to date, and only from the South Island. Tylodelphys darbyi has a 3-host life cycle consisting of an unidentified snail, a freshwater fish (Gobiomorphus cotidianus), and the Australasian crested grebe (Podiceps cristatus australis). To date, T. darbyi has been found in 2 locations, Lake Hayes, in the eyes of G. cotidianus, and Lake Wanaka, adults recovered from grebes. Considering the near ubiquity of the fish host in New Zealand, it is likely the bird, listed as nationally vulnerable, is the limiting factor in the range of T. darbyi. Up to 10 G. cotidianus were sampled from 10 mountain lakes known to have populations of grebe in the Otago and Canterbury regions of New Zealand's South Island. The eyes of all fish were examined and any metacercariae present were set aside for genetic analysis. In addition to expanding the known range of T. darbyi to at least 4 water bodies across the South Island, 2 new taxa of diplostomid were identified. A lens-infecting metacercariae clustered with Diplostomum spathaceum, while the metacercariae from the humor clustered with Diplostomum baeri., (© American Society of Parasitologists 2021.)

Thelazia californiensis is a spirurid nematode found in the conjunctival sac of domestic and wild animals, including humans, across the western United States of America. Herein, we report two cases of thelaziosis by T. californiensis in dogs from New Mexico, United States, based on integrated morphological and molecular approaches. Nematode specimens collected from the conjunctiva of both dogs were identified as T. californiensis based on morphology. Our study substantially expands the knowledge on morphometry of this nematode species. Therefore, these data will be useful for accurate diagnosis of thelaziosis in domestic animals, wildlife and humans in North America, using classical, microscopy-based methods. We characterized for the first time the mitochondrial cytochrome c-oxidase subunit 1 (COI) and 12S genes of T. californiensis. While these markers support the validity of T. californiensis, they were not very informative for elucidating the phylogenetic relationships among Thelazia species. Nevertheless, the characterization of these diagnostic markers for T. californiensis will be useful for studies on the epidemiology, molecular xenomonitoring of fanniid vectors, and population genetics of this multi-host, zoonotic parasite., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Intraspecific diet specialization, usually driven by resource availability, competition and predation, is common in natural populations. However, the role of parasites on diet specialization of their hosts has rarely been studied. Eye flukes can impair vision ability of their hosts and have been associated with alterations of fish feeding behavior. Here it was assessed whether European perch (Perca fluviatilis) alter their diet composition as a consequence of infection with eye flukes. Young-of-the-year (YOY) perch from temperate Lake Müggelsee (Berlin, Germany) were sampled in two years, eye flukes counted and fish diet was evaluated using both stomach content and stable isotope analyses. Perch diet was dominated by zooplankton and benthic macroinvertebrates. Both methods indicated that with increasing eye fluke infection intensity fish had a more selective diet, feeding mainly on the benthic macroinvertebrate Dikerogammarus villosus, while less intensively infected fish appeared to be generalist feeders showing no preference for any particular prey type. Our results show that infection with eye flukes can indirectly affect interaction of the host with lower trophic levels by altering the diet composition and highlight the underestimated role of parasites in food web studies.

Thelazia callipaeda is a vector-borne nematode transmitted by Phortica spp. (fruit flies) and one of the causes of mild to severe conjunctivitis and keratitis in dogs, cats, rabbits and humans. It has been formerly known as the oriental eye worm based on its geographic occurrence. By now, it has been shown to be endemic in several southern and eastern European countries as well as extending its geographic distribution further throughout Europe. In the present case report, T. callipaeda infection was diagnosed in a female dog from Germany. The dog was referred by a local veterinarian due to a treatment-resistant conjunctivitis. A comprehensive ophthalmologic examination revealed 3 adult eye worms in the conjunctival sac as well as on the bulbar side of the nictitating membrane of the left eye. These were identified by morphological features and molecular techniques as T. callipaeda and represented the primary cause of the dog's unilateral blepharospasm, hyperemic conjunctiva and epiphora. Treatment consisted of manual collection of the adult worms and the administration of moxidectin/imidacloprid as spot on (Advocate ® , Bayer). All clinical signs resolved within one week after treatment. In Germany, ocular thelaziosis still represents a rare disease. Usually, it is diagnosed in cats and dogs either imported from abroad or accompanying the owners on holiday travels to endemic countries. The dog presented in this case report was born in Germany. Except for a one-week stay in the Netherlands 11 months before the symptoms began, it had never traveled abroad. Considering the prepatency of T. callipaeda , an autochthonous transmission in this case is highly probable., Competing Interests: Die Autoren erklären, dass sie keine geschützten, finanziellen, beruflichen oder andere persönlichen Interessen haben, welche die im Manuskript dargestellten Inhalte oder Meinungen beeinflussen könnten., (Thieme. All rights reserved.)

The Northern bobwhite quail (Colinus virginianus) is a popular game bird that has been experiencing a well-documented decline throughout Texas since the 1960s. While much of this decline has been attributed to habitat loss and fragmentation, recent studies have identified other factors that may also contribute to decreasing quail populations. Parasites, in particular, have become increasingly recognized as possible stressors of quail, and some species, particularly the eyeworm (Oxyspirura petrowi) and cecal worm (Aulonocephalus pennula) are highly prevalent in Texas quails. Eyeworm infection has also been documented in some passerines, suggesting helminth infection may be shared between bird species. However, the lack of comprehensive helminth surveys has rendered the extent of shared infection between quail and passerines in the ecoregion unclear. Thus, helminth surveys were conducted on bobwhite, scaled quail (Callipepla squamata), Northern mockingbirds (Mimus polyglottos), curve-billed thrashers (Toxistoma curvirostre), and Northern cardinals (Cardinalis cardinalis) to contribute data to existing parasitological gaps for birds in the Rolling Plains ecoregion of Texas. Birds were trapped across 3 counties in the Texas Rolling Plains from March to October 2019. Necropsies were conducted on 54 individuals (36 quail and 18 passerines), and extracted helminths were microscopically identified. Nematode, cestode, and acanthocephalan helminths representing at least 10 helminth species were found. Specifically, A. pennula and O. petrowi had the highest prevalence, and O. petrowi was documented in all of the study species. This research adds to the body of knowledge regarding parasitic infections in quail and passerines of the Rolling Plains ecoregion and highlights the potential consequences of shared infection of eyeworms among these bird species., (© American Society of Parasitologists 2021.)

Background: Countries of eastern Europe are considered, due to several risk factors, more vulnerable to infections with newly (re)emerging pathogens. During the last decade, in several European countries, reports of autochthonous cases of ocular thelaziosis due to Thelazia callipaeda have been published, posing a great concern from both veterinary and public health perspective. However, in the Republic of Moldova only limited epidemiological data are available regarding zoonotic vector-borne pathogens and, until now, no data exist on the zoonotic nematode T. callipaeda., Methods: In September 2018, an 11-year-old dog, mixed-breed, intact male was referred to a private veterinary clinic from Chișinău, Republic of Moldova, with a history of 2 weeks of an ocular condition affecting the right eye. The ophthalmological exam revealed the presence of nematode parasites in the conjunctival sac and under the third eyelid. The collected parasites were identified by morphological techniques and molecular analysis., Results: A total of 7 nematodes were collected, and 5 females and 2 males of T. callipaeda were identified morphologically. The BLAST analysis confirmed the low genetic variability of this parasite in Europe. The travel history of the patient allowed us to confirm the autochthonous character of the case., Conclusions: To the best of our knowledge, this is the first report of thelaziosis in dogs from the Republic of Moldova, which confirms the spreading trend of T. callipaeda and the existence of an autochthonous transmission cycle of this zoonotic parasite in the country.

The occurrence of Setaria digitata in a horse is reported for the first time in Malaysia. An 8-year-old Thoroughbred cross mare was referred to the University Veterinary Clinic with the primary complaint of corneal opacity and excessive eye discharge. After initial treatment with Terramycin eye ointment, corneal opacity cleared partially to reveal a moving thread-like cylindrical worm in the anterior chamber of the eye. The parasite was successfully removed surgically, and examination under the light microscope revealed that the isolated worm (length = 45 mm) was a 5th stage larva of S. digitata based on morphological criteria. Confirmation of the species of the worm was through molecular methods. The 12S rRNA gene was PCR-amplified, and the purified amplicon was directly sequenced. Phylogenetic analyses revealed that the isolated roundworm showed 100% sequence similarity with that of S. digitata in NCBI GenBank database (Accession no.: KY284626.1). This report is the first confirmed case of equine ocular setariasis by S. digitata in Malaysia. The current study provides evidence that S. digitata is an etiological agent of ocular infection and its presence in Malaysia., (Copyright © 2019 Elsevier B.V. All rights reserved.)

An-eighteen months (one and half years) old heifer was presented with a progressive loss of weight leading to cachexia and was attended to by a team of doctors from the ambulatory clinic of the School of Animal Science and Veterinary Medicine, University of Rwanda. Clinical examination revealed scleroderma of both sides of the neck and pinpoint cysts in the sclera and conjunctiva as well as corneal opacity of the left eye. Histological examination of skin biopsy showed a mononuclear dermatitis with several cysts of 100-300 μm filled up with bradyzoites in the subcutis and dermis. These lesions are consistent with bovine besnoitiosis, a disease caused by Besnoitia besnoiti in cattle. To the best of our knowledge, this is the first confirmed case of bovine besnoitiosis in Rwanda., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Within-host interactions between co-infecting parasites can significantly influence the evolution of key parasite traits, such as virulence (pathogenicity of infection). The type of interaction is expected to predict the direction of selection, with antagonistic interactions favouring more virulent genotypes and synergistic interactions less virulent genotypes. Recently, it has been suggested that virulence can further be affected by the genetic identity of co-infecting partners (G × G interactions), complicating predictions on disease dynamics. Here, we used a natural host-parasite system including a fish host and a trematode parasite to study the effects of G × G interactions on infection virulence. We exposed rainbow trout (Oncorhynchus mykiss) either to single genotypes or to mixtures of two genotypes of the eye fluke Diplostomum pseudospathaceum and estimated parasite infectivity (linearly related to pathogenicity of infection, measured as coverage of eye cataracts) and relative cataract coverage (controlled for infectivity). We found that both traits were associated with complex G × G interactions, including both increases and decreases from single infection to co-infection, depending on the genotype combination. In particular, combinations where both genotypes had low average infectivity and relative cataract coverage in single infections benefited from co-infection, while the pattern was opposite for genotypes with higher performance. Together, our results show that infection outcomes vary considerably between single and co-infections and with the genetic identity of the co-infecting parasites. This can result in variation in parasite fitness and consequently impact evolutionary dynamics of host-parasite interactions., (© 2019 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2019 European Society For Evolutionary Biology.)

In the past decade, canine thelaziosis due to Thelazia callipaeda has been diagnosed in an increasing number of European countries, with endemic areas being identified. A multi-center field trial was conducted in endemic areas in France and Spain to evaluate the efficacy of monthly administrations of the oral milbemycin oxime/afoxolaner combination (NexGard Spectra ® ) for the prevention of T. callipaeda infection in at-risk dogs. A total of 79 dogs negative for T. callipaeda and with a clinical history of eyeworm infection in the past two years completed the study. Dogs were randomly allocated either to a negative control group (42 dogs) or to the NexGard Spectra ® treated group (37 dogs). All dogs were followed up for a 6-month period and assessed monthly for the presence of nematodes on the eyes and for the signs of ocular thelaziosis (e.g., conjunctivitis, keratitis, and ocular discharge). When the presence of nematodes was confirmed, the conjunctival fornix was flushed with a saline solution for parasite recovery and counting, and the dogs were treated appropriately. Recovered parasites were stored in 70% alcohol for subsequent morphological identification. During the course of the study, 57.1% (24/42) of the control dogs were diagnosed positive for Thelazia infection, which illustrates a high incidence rate of parasite infection. Conversely, no eyeworm was recovered from any of the 37 dogs that received NexGard Spectra ® . All parasites sampled were confirmed to be T. callipaeda. This clinical field study demonstrated that monthly administrations of NexGard Spectra ® provided 100% preventive efficacy against canine thelaziosis., (© W. Lebon et al., published by EDP Sciences, 2019.)

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.

A two-year-old cat from Tenerife, Canary Islands (Spain), presented with two months history of uveitis in the left eye. It had been treated for two months but still showed an active uveitis. After new treatment, eye examination showed a mobile worm in the anterior chamber. Following surgical removal, the worm was obtained. Morphological study revealed that it was a male metastrongyloid nematode (Nematoda: Metastrongyloidea) with caudal bursa and two similar spicules. Molecular tools based on the 18Sr RNA gene sequence identified the parasite as Gurltia paralysans, which is a neurotropic nematode previously found in South America. Therefore, this article describes the first report of ophthalmic case of parasitism by G. paralysans, and cites for first time this species out of South America., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Background: The fruit fly Phortica variegata (Drosophilidae: Steganinae) feeds on the ocular secretions of animals and humans, and has been described as an intermediate host of the eye worm Thelazia callipaeda (Spirurida: Thelaziidae) in Italy. Despite the increased detection of T. callipaeda in many European countries, information about its vector role in natural conditions is still limited. In the Iberian Peninsula, thelaziosis caused by T. callipaeda has been reported in dogs, cats, red foxes, wild rabbits and humans., Methods: In the last seven years, we have detected increased numbers of cases of canine thelaziosis at three locations in mainland Spain: Site 1, La Vera region (Cáceres Province, central-western Spain; 51 cases); Site 2, El Escorial municipality (Madrid Community, central Spain; 23 cases); and Site 3, Miraflores de la Sierra municipality (Madrid Community, central Spain; 41 cases). Site 1 is considered endemic for T. callipaeda while the other two sites have been recently recognised as risk zones for T. callipaeda infection., Results: From June 2016 to September 2017, 2162 flies were collected and morphologically identified as Phortica spp. (Site 1, n = 395; Site 2, n = 1544; and Site 3, n = 223). Upon dissection, third-stage T. callipaeda larvae were found in two out of 155 flies examined from Site 1, and both these larvae tested molecularly positive for the eye worm. Of the 395 flies collected from Site 1, 371 were molecularly processed for arthropod species identification and T. callipaeda detection. All 371 flies were identified as P. variegata and 28 (7.5%; 95% CI: 4.8-10%) tested positive for T. callipaeda DNA haplotype 1., Conclusions: Our findings indicate that T. callipaeda circulates among dogs and P. variegata in Spain, where zoonotic cases have been also reported. The co-existence of canine thelaziosis and Phortica spp. in geographical areas previously considered free of the eye worm indicates a risk of infection for both animals and humans living in this region.

Onchocerca lupi is an emerging zoonotic parasite infecting the ocular connective tissue of dogs, cats and humans. The only known case of canine ocular onchocerciasis in Germany was documented in 2002 in a shelter dog. However, the species of Onchocerca causing the infection could not be identified. Here, we report a case of the ocular infection with O. lupi in a dog, confirmed by PCR and sequencing of the cox1 gene. Further investigations are required to assess the risk factors for transmission and spread of the parasite in Germany., (© 2017 Blackwell Verlag GmbH.)

Thelazia callipaeda (Spirurida, Thelaziidae), the so-called oriental eyeworm, has been increasingly reported as an agent of infection in animals and humans from many European countries. Clinical signs range from subclinical to moderate or severe ocular disorders (e.g., epiphora, photophobia, conjunctivitis, keratitis, ulcers). The disease has been also diagnosed in animals from countries of the Balkan area (e.g., Croatia, Bosnia and Herzegovina and Serbia), but only a single case of canine thelaziosis, presumably autochthonous, was reported in Northern Greece. In this study, we provide robust information of the occurrence of thelaziosis in Greece by reporting autochthonous cases of thelaziosis in dogs (n = 46), cats (n = 3) and in one rabbit (Oryctolagus cuniculus) living in Northern and Central regions of Greece. The occurrence of a single haplotype of the cytochrome oxidase subunit 1 gene confirms that the same zoonotic haplotype of the parasite circulating in Europe is also spreading in Greece. The increased awareness of this parasitosis is crucial to limit the risk of further infections in both humans and animals in European countries., (© 2017 Blackwell Verlag GmbH.)

Parasites that occupy the eyes of fish have the potential to affect visual perception and consequently alter the host's behaviour, as these organs provide information about their surroundings. In an experimental study, the feeding behaviour of European perch (Perca fluviatilis) infested with the eye fluke Tylodelphys clavata was examined. The results showed that an individual's ability to identify and approach food items was negatively affected by the infestation intensity of T. clavata. Additionally, the foraging success of an individual was reduced in competition with another, less heavily infested conspecific, when the same food resource was exploited. These alterations in the ability to locate food may have important consequences on the feeding strategy of the fish. Furthermore, the impaired feeding capability caused by T. clavata may also increase the predation risk as heavily infested fish need to spend more time foraging to attain a rate of food intake equivalent to less infested conspecifics.

Northern bobwhite (Colinus virginianus) and Scaled quail (Callipepla squamata) have been declining steadily throughout much of their historical range over the past few decades. Even the Rolling Plains of Texas, historically rich with wild quail and one of the last remaining quail strongholds, has been suffering a population decline, most notably since 2010. Gambel's quail (Callipepla gambelii) have also been experiencing their own decline throughout their respective range, but not as significant as that of other species of quail. Eyeworms (Oxyspirura petrowi) in quail have been recognized for years but not thoroughly studied until recently. New research reveals that O. petrowi infection can cause inflammation, oedema, and cellular damage to the eye of the quail host. The objective of this research was to better understand the prevalence of the eyeworm infection in different quail species, expand on known distribution, and determine if there is a relationship between location and species infected with eyeworms. Northern bobwhite, Scaled quail and Gambel's quail were hunter-donated from one county within Texas, New Mexico and Arizona, and examined for the prevalence, mean abundance and mean intensity of eyeworm infection from November 2013 to February 2014. Quail from every location were found to have individuals with a varying degree of eyeworm infection. This is the first study to document eyeworm infection in Gambel's quail and in quail in New Mexico and Arizona, and reports the highest eyeworm infection found in Northern bobwhite and Scaled quail.

Several trematode species infect the eyes of fish as second intermediate hosts. In most cases the definitive host is a piscivorous bird. Studies of a few species have shown an increase in transmission due to decreased visual acuity of the fish host. However, this may vary depending on trematode microhabitat choice within the eye. Some trematode species are found in the lens, some are found in the vitreous humor, and others have been reported from the retina. Here we report 3 genera of eyeflukes in 3 locations of the eye in the intermediate fish host, Gambusia affinis . Clinostomum metacercariae were found attached to the outer sclera within the eye orbit, and Diplostomum metacercariae were found in the lens. Posthodiplostomum metacercariae were confirmed by histology to reside between the choroid and pigmented retina. Posthodiplostomum metacercariae were found in both eyes of all 20 fish examined and in high intensities (up to 27 metacercariae per eye). High trematode intensities between the choroid and pigmented retina found in this study may disrupt vision in this fish host. Our study is the first to document the microhabitat of all 3 trematode metacercariae within the eye of G. affinis .

Parasitic infection often results in alterations to the host's phenotype, and may modify selection pressures for host populations. Elucidating the mechanisms underlying these changes is essential to understand the evolution of host-parasite interactions. A variety of mechanisms may result in changes in the host's behavioural phenotype, ranging from simple by-products of infection to chemicals directly released by the parasite to alter behaviour. Another possibility may involve parasites freely moving to certain sites within tissues, at specific times of the day to induce behavioural changes in the host. We tested the hypothesis that parasites shift to certain sites within the host by quantifying the location and activity of the trematode Tylodelphys sp., whose mobile metacercarial stages remain unencysted in the eyes of the second intermediate fish host, the common bully (Gobiomorphus cotidianus). This parasite's definitive host is a piscivorous bird feeding exclusively during daytime. Ocular obstruction and metacercarial activity were assessed within the sedated host's eye at three time points 24 h-1 period, using video captured via an ophthalmoscope. Although observed metacercarial activity did not change between time periods, ocular obstruction was significantly reduced at night. Increased visual obstruction specifically during the foraging time of the parasite's definitive host strongly suggests that the parasite's activity pattern is adaptive.

This study reports the occurrence of Austrodiplostomum compactum metacercariae in the freshwater fish Schizodon intermedius (ximborê/piava) from a Neotropical reservoir in the Paranapanema River, state of São Paulo, Brazil. From a total of 75 fish collected, we found 38 infected with A. compactum metacercariae (prevalence = 50.67%) in the eyes. The mean intensity of infection and mean abundance were 9.05 ± 4.26 (1-155) and 4.59 ± 2.20 (0-155), respectively. Poulin's Discrepancy Index was 0.87 and four specimens presented more than 10 metacercariae in their eyes. No correlation was observed between parasite abundance and standard length, total weight and condition factor (p>0.05). These metacercariae are reported for the first time in S. intermedius.

Background: Thelazia callipaeda is a zoonotic nematode that affects the eyes of domestic and wild animals, including dogs, cats and red foxes. This parasitic eye worm is transmitted by Phortica variegata, which is a zoophilic fruit fly spread in Europe. Two wild European rabbits (Oryctolagus cuniculus) found dead in north-eastern Portugal were submitted to necropsy., Results: Both animals presented gross lesions compatible with haemorrhagic viral disease. Eye examination revealed the presence of six worms (three in each animal, on both eyes). Out of the six nematodes, five females and one male were morphologically and molecularly identified as T. callipaeda., Conclusions: This is the first report of T. callipaeda in wild rabbits from Portugal, which reveals a new host for this parasite in southern Europe and emphasizes the importance of including thelaziosis in the differential diagnosis of ocular alterations in both animals and humans from areas where the eye worm is endemic.

Objective: To describe five cases of protozoal keratitis or conjunctivitis in dogs with chronic preexisting ocular surface disease treated with long-term immunosuppression., Animals Studied: Five dogs that developed corneal or conjunctival mass lesions., Procedures: The database of the Comparative Ocular Pathology Laboratory of Wisconsin was searched for canine cases diagnosed with corneal or conjunctival protozoal infection. Five cases were identified, and tissues were examined using routine and special histochemical stains: immunohistochemical labels for Neospora caninum, Toxoplasma gondii, and Leishmania spp., and tissue sample PCR for Leishmania spp., Trypanosoma cruzi, tissue coccidia (i.e., T. gondii/Sarcocystis/Neospora), piroplasms, trichomonads, and Acanthamoeba. Electron microscopy was performed for two cases, and serology for N. caninum and T. gondii was available for three cases., Results: Preexisting ocular diseases included keratoconjunctivitis sicca and pigmentary keratitis (n = 4) and pyogranulomatous meibomian adenitis (n = 1). All dogs were treated with tacrolimus or cyclosporine for at least 1.2 years. Dogs were presented with fleshy corneal or conjunctival masses that were clinically suspected to be neoplastic (n = 4) or immune mediated (n = 1). Histologic examination revealed granulomatous inflammation with intralesional protozoal organisms. Amoeba (n = 2), T. gondii (n = 2), or Leishmania mexicana (n = 1) were identified using molecular techniques. Serological tests were negative., Conclusions: Protozoal keratitis and conjunctivitis without systemic involvement appears rare and may be associated with chronic preexisting ocular surface disease treated with long-term immunosuppression. Based upon clinical appearance, lesions could be confused with neoplasia. This is the first report of amoebic keratoconjunctivitis in dogs and of L. mexicana in dogs in the United States., (© 2015 American College of Veterinary Ophthalmologists.)

Thelazia callipaeda eyeworm has been frequently reported parasitizing humans in Asia. In Europe, the parasite is endemic in wild and domestic carnivores and only eight cases have been reported in humans so far. We describe the first case of human thelaziosis in Serbia, along with two cases in dogs from the same area. A One Health approach, based on cooperation amongst veterinarians and physicians, is strongly advised for this emerging infection in order to assess the risk for and prevent of the zoonotic infection., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Ocular diplostomiasis is caused by trematode species in the family Diplostomidae, specifically those in the genera Austrodiplostomum, Diplostomum, and Tylodelphys. Diplostomid trematodes are globally distributed parasites of fish. Heavy infections of diplostomids that parasitize the eyes of fish can result in acute mortality while chronic infections are often characterized by impaired vision or blindness. In the southeastern United States, commercial catfish production is threatened by piscivorous birds and the many trematode species that parasitize them. The life cycles typically involve a piscivorous avian definitive host, a mollusk first intermediate host, and a fish second intermediate host. A survey of parasites infecting the snail host Biomphalaria havanensis (= B. obstructa ) in catfish production ponds was undertaken. Snails were collected from 2 separate ponds during the summer of 2014 and observed for the release of trematode cercariae. A total of 1,740 snails were collected. Three distinct longifurcate pharyngeate cercariae were observed and these cercariae were characterized morphologically and molecularly. Sequencing of ∼4,200 base pairs (bp) of the nuclear ribosomal genes and ∼450 bp of the mitochondrial cytochrome c oxidase gene revealed 3 genetically distinct species. One morphotype shared 99-100% sequence identity with metacercariae from the aqueous and vitreous humors of gizzard shad Dorosoma cepedianum and channel catfish Ictalurus punctatus as well as an adult trematode, Austrodiplostomum ostrowskiae, a parasite of the double-crested cormorant Nannopterum auritus. The remaining 2 cercariae morphotypes shared 99-100% sequence identity with an unidentified Tylodelphys sp. and Austrodiplostomum sp. metacercaria from the brain and eyes of several freshwater fish. Herein we molecularly link the cercaria, metacercaria, and adult stage of the life cycle of A. ostrowskiae, identifying the snail host for this parasite, in addition to providing notes on 2 cercariae representing 2 other diplostomids.

A captive female square-lipped rhinoceros born in 1993 had been showing intermittent signs of bilateral conjunctivitis and conjunctival proliferation since 1998. Periodic improvement was noted, especially in winter, but overall the condition had deteriorated over the years. Treatment with various topical, intralesional, and systemic antibiotics and glucocorticosteroids was largely ineffective, as were repeated dewormings. No primary cause for these lesions was found in biopsies taken in 2000 and 2006, although a severe infiltrate of numerous eosinophils was observed in the latter. As the condition worsened, secondary corneal changes were noted, and eventually vision was lost due to proliferative conjunctival tissue. Aggressive resection of the proliferating tissue in 2013 restored vision and submitted biopsies yielded a diagnosis of severe allergic conjunctivitis, eosinophilic granuloma, and habronematid (Habronema or Draschia) larval infection. As no other rhinoceros in the herd was affected, including two calves born to the patient who were in close contact with their mother, it was concluded the presentation was most likely due to a hypersensitivity reaction to the dead or dying larvae. Fly repellent is now regularly applied around the eye of this rhinoceros, and a protective face mask has been fitted. Ongoing periodic relapses are treated with oral ivermectin, topical antibiotics, and steroids., (© 2015 American College of Veterinary Ophthalmologists.)

The effects of Oxyspirura petrowi infections in northern bobwhites ( Colinus virginianus ) are not well understood. While studies have reported O. petrowi infections, none has histopathologically examined the eye surface and intraorbital glands to assess cellular-level impacts associated with infection. This study is the first to document the histopathology associated with O. petrowi infections. Oxyspirura petrowi occurred on the eye surface as well as in the conjunctiva, lacrimal ducts, lacrimal glands, and Harderian glands. Histopathology showed infections of O. petrowi caused cellular damage to these tissues, scarring and interstitial keratitis of the cornea, and acinar atrophy of the Harderian gland.

Northern bobwhite ( Colinus virginianus ) have experienced a dramatic decline in West Texas over the last 3 yr, and investigations are underway to evaluate the role of parasites in this decline. One of the key parasites being investigated is the eyeworm (Oxyspirura petrowi). Live eyeworms were extracted from both live and dead northern bobwhites, and in vitro survival was tested using 10 liquid media. Eyeworms placed in an egg white and physiological saline solution lived for at least 36 days. Live O. petrowi placed into the eyes of uninfected pen-raised bobwhites were monitored for 21 days to demonstrate successful transfer. Eyeworm behavior during feeding, mating, and development were monitored. This study is important to research that requires "banking" of live O. petrowi from wild-captured definitive hosts for life history studies and assessing the impact of O. petrowi on host individuals.

A 1-year-old female spayed mixed-breed dog was presented for evaluation of acute onset of lethargy and blepharospasm OD. Slit-lamp biomicroscopy revealed a segmented larva embedded in the inferonasal iris. Moderate anterior uveitis was present. After pharmacologic dilation, mild vitreal hemorrhage and chorioretinal migration tracks were identified. The dog was treated empirically for uveitis for 5 days, after which a keratotomy and larval foreign body extraction was performed. The dog recovered uneventfully from intraocular surgery and remained visual and comfortable. Parasite evaluation confirmed the larva to be a Cuterebra sp. To the authors' knowledge, this is the first report of canine ophthalmomyiasis interna anterior, and the first report of successful surgical removal from the anterior segment in a dog with preservation of vision., (© 2014 American College of Veterinary Ophthalmologists.)

Thelazia callipaeda is a spiruroid nematode of dogs, cats and wild carnivores transmitted by zoophilic drosophilid Phortica flies and found in an increasing number of European countries. In cats the disease is diagnosed sporadically. This study presents an epidemiological investigation of feline thelaziosis, performed in southern Ticino, Switzerland, an endemic area for T. callipaeda. Between January 2009 and July 2011 2171 cats, having outdoor access and presenting for various reasons, were examined by in-depth eye examinations, and clinical and anamnestic data were collected. The overall prevalence of T. callipaeda in the study area was 0.8% (17/2171 cats, 95% confidence interval: 0.5-1.3%). Among cats showing ocular illness, the prevalence was 9.2% (11/120, CI: 4.7-15.8%). Cats with eye worms had no international travel history and were significantly more often diagnosed between June and December than during other months. With one exception, one single eye per cat was infested, each harboring between 1 and 10 eye worms (arithmetic mean: 2.8 per cat). One cat presented with conjunctivitis and ulcers, seven with conjunctivitis only and 3 with a mildly increased lacrimation, while 6 cats were asymptomatic. Significantly more male than female cats had eye worms and cats older than one year were overrepresented. No pure-bred cats were infested. This study confirms the establishment of this potentially zoonotic parasite in cats from the study area. Due to the clinical relevance and pain caused by the infestations, increased disease awareness and in depth eye examination for the detection of T. callipaeda in cats are recommended, even in absence of obvious clinical signs, in order to initiate appropriate anthelmintic treatment., (Copyright © 2014 Elsevier B.V. All rights reserved.)

New occurrences and effects of parasitism by metacercariae in fish eyes have recently been discussed in many studies. The aim of the present study was to evaluate the infection levels of the eye flukes Sphincterodiplostomum musculosum Dubois, 1936 (metacercariae) in Steindachnerina insculpta (Fernádez-Yépez, 1948) from three ecosystems under the influence of the Jurumirim reservoir (Paranapanema, Taquari and Veados Rivers). A total of 174 fish specimens were sampled between April 2011 and April 2012. There were high levels of infection by S. musculosum metacercariae in the eyes of S. insculpta from all the sampled ecosystems, thus presenting broad geographical distribution. The histological analyses revealed that the metacercariae were apparently lodged behind the retina. The smaller fish from the Taquari River were less parasitized by metacercariae than the adults. This pattern can be explained by the cumulative effect of parasitism, as demonstrated by the positive correlation between the abundance of metacercariae and fish body size.

Traira (Hoplias malabaricus) is a neotropical fish that is widely distributed in freshwater environments in South America. In the present study, we documented the occurrence of metacercariae of Austrodiplostomum spp. (Diplostomidae) in the eyes and cranial cavity of H. malabaricus and described parasite-induced behavioral changes in the host. The fish were collected from the upper São Francisco River, in the Serra da Canastra mountain range, Minas Gerais, transported alive to the laboratory, observed for 2 weeks, and subsequently examined for parasites. Of the 35 fish examined, 28 (80 %) had free metacercariae in the vitreous humor (mean intensity=95.4; mean abundance=76.3), and 24 (68.57 %) had free metacercariae in the cranial cavity, mainly concentrated below the floor of the brain, at the height of the ophthalmic lobe (mean intensity=12.91; mean abundance=8.85). Specimens of H. malabaricus with a high intensity of infection in the brain displayed changes in swimming behavior.

A leech was found parasitizing the ocular orbit of a common redstart captured during a faunistic survey of Antikythira in the Aegean Sea during the spring migration of 2012. Morphological and molecular characterizations placed the leech in the mucous-membrane specific leech family Praobdellidae and definitively as the species Parapraobdella lineata. This is the first record of any leech parasitizing a passerine bird, Phoenicurus phoenicurus , and the first of a praobdellid leech on any avian host.

The eye-fluke Philophthalmus gralli (Philophthalmidae Looss, 1899) was found in six birds known as great tinamous (Tinamus major) reared in a wild animal shelter located in Alajuela, Costa Rica. The birds presented conjunctival hyperemia, blepharitis, anorexia and weakness. Some of them suffered from unilateral blindness and ocular loss. After morphometric analysis, the specimens showed characteristics compatible with the digenean trematode P. gralli. The clinical signs of infection were resolved by manual removal of the adults, treatment with praziquantel and relocation into an environment without a natural water source. In order to determine if an ongoing cycle of this pathogen was present in the shelter, the habitat of the birds was inspected for the presence of infected intermediate hosts and contaminated water and objects. It was found that the snails Melanoides tuberculata acted as the intermediate host, and reared the infectious stages toward other animals, as shown by the reproduction of ocular philophthalmiasis in chickens artificially infected with excysted metacercaria. Moreover, three out of every ten snails found in the place were infected with rediae of P. gralli, raising the possibility of the dispersion of the parasite into new environments as well as the imminent zoonotic risk. The finding of P. gralli in Costa Rica is the first official report in Central America., (© 2013.)

Austrodiplostomum compactum has been involved in cases of ocular diplostomiasis in several species of fish in Brazil, but the molluscan intermediate hosts of the parasite remain unknown. In the present study, malacological surveys were carried out at Pampulha Reservoir, Belo Horizonte, Minas Gerais, Brazil, between January 2009 and July 2012. A total of 16,119 specimens of Biomphalaria spp. were collected and examined, of which 68/14,948 specimens (0.45%) of Biomphalaria straminea and 6/541 (1.11%) of Biomphalaria glabrata were found harboring a strigeid cercariae. Groups of 5 specimens of Cyprinius carpio were experimentally infected with these cercariae (100 larvae/fish), and metacercariae were recovered from the eyes of the fish, 65 days after infection, with a mean intensity of infection of 10.4 (8-13) metacercariae/fish. Morphological study on cercariae and metacercariae identified them as A. compactum . This is the first record of cercariae of A. compactum in Brazil, and B. straminea and B. glabrata as new intermediate hosts for the parasite.

Until now, four species of eye trematodes have been found in South America. Of them, Philophthalmus lucipetus (synonymized with Philophthalmus gralli) displays a broad host spectrum, with at least 30 bird species (prevalently large water birds), five mammal species and humans serving as definitive hosts, and with snails Fagotia (Microcolpia) acicularis, Amphimelania holandri, Melanopsis praemorsa and Melanoides tuberculata serving as intermediate hosts. When examining a total of 50 birds of ten species in the wetland of Pantanos de Villa, Lima, Peru in July 2011, eye trematodes were identified visually in the edematous conjunctival sac of 11 (48%) out of 23 resident many-colored rush tyrants Tachuris rubrigastra. Based on morphometric characteristics, the trematodes were identified as P. lucipetus. ITS2 and CO1 gene of the examined specimens combined showed a 99% similarity to an Iranian isolate of Philophthalmus sp. from the intermediate host Melanoides tuberculata, an invasive freshwater snail, suggesting that these two isolates represent the same species with a wide geographical range. Moreover, the prevalence of infection with the philophthalmid cercariae was 31% in 744 Melanoides tuberculata examined in Pantanos de Villa in 2010. It is evident that P. lucipetus occurs throughout the world as well as locally, including Eurasia and South America. Here we report this trematode for the first time in Peru, and we were the first to sequence any of the South American eye trematodes. Low host specificity of P. lucipetus and the invasive character of Melanoides tuberculata as a competent intermediate host suggest that eye trematodosis caused by P. lucipetus may emerge frequently in various parts of the world, especially in the tropics. Increase of the zoonotic potential of the P. lucipetus associated with this invasive snail spreading across the world is predictable and should be of interest for further research., (Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.)

Nematode worms were retrieved from the left eyes of two dogs presented for unilateral ocular discharge in Belgium. Morphological and molecular identification were performed and the parasites were identified as Thelazia callipaeda. The history suggested that the infection had been acquired in south-western France and southern Italy where the disease has been observed regularly for the last 6 and 12 years, respectively. In these two regions, the disease is considered endemic and spreading. To the authors' knowledge, this is the first case report of canine thelaziosis in Belgium., (© 2012 British Small Animal Veterinary Association.)

Leishmaniasis is a disease common to humans as well as wild and domestic animals. When it affects pets, it primarily involves dogs, which constitute a parasitic reservoir. This disease is observed in Africa, Asia, and America and around the entire Mediterranean coast. We report an ocular form of leishmaniasis in a cat from the Var region., (Copyright © 2013 Elsevier Masson SAS. All rights reserved.)

A bald eagle (Haliaeetus leucocephalus) was found unable to fly and was admitted to The Raptor Center (TRC). Major clinical signs were thin body condition and a cardiac arrhythmia. Ten days after admission to TRC, ophthalmic examination revealed multiple, distinct serpiginous lesions of chorioretinal atrophy in the ocular fundus of the right eye (OD). The bird was euthanized because of clinical deterioration and poor prognosis. Mites of an undetermined species were found histologically in the retina, episcleral tissues, lungs, and liver at the postmortem examination. Disseminated mite infection should be considered in the differential diagnosis of serpiginous chorioretinal lesions in bald eagles (H. leucocephalus)., (© 2011 American College of Veterinary Ophthalmologists.)

A 4-month-old crossbred female dog presented with complaints of poor vision and odd appearance of the eyes. At the age of a month, the animal was found lying in a railway road in a very bad condition and was rescued from death. At that time, the patient was presented with severe bilateral ocular discharge, and from both eyes, dipterous fly larvae were extracted. The dog was given symptomatic treatment (deworming, topical and systemic antibiotics, nutritional support) but never regained a normal eye appearance. At the time of the initial presentation, it had severe vision impairment because of bilateral cicatricial symblepharon, total in the left eye and occupying 3/4 of the cornea in the right eye. Surgery was proposed to attempt a resolution. Superficial keratectomy was performed in both eyes. After a midline incision in the cornea, the conjunctiva was dissected away. The conjunctiva was apposed to and sutured to the limbus and secured in the upper and lower conjunctival fornix. Additionally, in the left eye, a lateral canthotomy and canthoplasty were performed to enlarge the size of the eyelid opening. The corneal epithelium healed without complications, the patient regained vision, and after 36 months of follow-up, no recurrences were observed. To the authors' knowledge, this is the first report of symblepharon secondary to ophthalmomyiasis externa in a dog., (© 2011 American College of Veterinary Ophthalmologists.)

Selection on parasites should favor adaptations that maximize the probability of transmission to the definitive host, such as the preference for and use of intermediate hosts or encystment substrata that are likely to be consumed by the definitive host. Eye flukes in the genus Philophthalmus are passed to their definitive avian host through the ingestion of metacercariae encysted on hard substrata. The life cycle of these parasites is generally well understood; however, there is almost no information on substratum use or preference of the cercariae of these parasites. In this study, we combine a survey of naturally occurring substrata with experimental, laboratory-based choice tests to determine the preferred substratum of Philophthalmus sp. and whether this preference is affected by the presence and density of pre-existing cysts. A concordance between natural and experimental data show a preference for the shells of multiple species of snail over other hard substrata that are common at the field site, including seaweed, other molluscs, and crustaceans. In addition, we found that cercariae preferred substrata with pre-existing cysts and that this preference seemed to increase with increasing cyst density. Such a preference should lead to an aggregated distribution of cysts among snail shells that may benefit the parasite by increasing the number of potential mates that become established in the definitive host. The identification of a preferred substratum also may help to identify potential definitive hosts that were previously unknown.

An 8 wk old Scottish terrier was evaluated for a 2×2 cm mass located directly adjacent to the lateral canthus of the right eye. Examination revealed a well-developed Cuterebra larva at the lateral aspect of the orbital cavity, anchored at the lateral canthus. The larva was manually removed under general anesthesia, and the eyelid margin was repaired. Systemic and topical antibiotics along with systemic anti-inflammatory treatment were instituted. The lesion healed completely, revealing a normal functional right eye 10 days after removal of the Cuterebra larva. Careful manual removal of the larva is recommended along with correction of any resultant conformational defects. The remaining cavity can be left to heal; however, antibiotic therapy is recommended.