DISTRIBUTION AND DIVERSITY OF DIPLOSTOMIDS IN NEW ZEALAND.

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.

A Rare Case of Congenitally Acquired Ocular Toxocariasis in A Five-Week-Old Infant.

PURPOSE: To report a case of strabismus in a five-week-old infant, likely secondary to a rare occurrence of congenitally acquired ocular toxocariasis. METHODS: Retrospective case report. RESULTS: A five-week-old male infant with left exotropia was referred to pediatric ophthalmology and to a vitreoretinal specialist. Fundoscopic examination revealed a granuloma with associated retinal folds and tractional retinal detachment typical for ocular toxocariasis. Serology revealed positivity for Toxocara antibodies, consistent with the clinical diagnosis of ocular toxocariasis. CONCLUSION: Ocular toxocariasis is typically thought to be secondary to acquired Toxocara infection secondary to fecal-oral transmission. In this case of early-onset strabismus secondary to ocular toxocariasis, it is hypothesized that this is a presentation of congenitally acquired toxocariasis.

[Ocular thelaziosis in a dog in Germany - an autochthonous case?] / Okuläre Thelaziose bei einem Hund in Deutschland ­ ein autochthoner Fall?

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.

A first report of Thelazia callipaeda infection in Phortica okadai and wildlife in national nature reserves in China.

BACKGROUND: Thelazia callipaeda is a zoonotic parasitic nematode of the family Thelaziidae, with Phortica okadai as its intermediate host and only confirmed vector in China. China has the largest number of human cases of thelaziosis in the world. It is generally believed that infected domestic animals (dogs and cats) are the most important reservoir hosts of T. callipaeda, and thus pose a direct threat to humans. At present, there is little research or attention focused on the role of wildlife in the transmission cycle of thelaziosis in nature reserves. METHODS: We selected locations in four national nature reserves across China to monitor P. okadai and wildlife. We used a fly-trap method to monitor P. okadai density. Morphological analysis of the parasites collected from the conjunctival sac of the infected wildlife was undertaken as the first step in species identification, and polymerase chain reaction (PCR) was used for species confirmation. RESULTS: In 2019, the density of P. okadai in Foping National Nature Reserve in China increased sharply, and infected P. okadai were newly found in the reserve. Giant panda, wild boar, leopard cat, and black bear were found to be newly infected with T. callipaeda (one individual of each species). A total of four worms were collected, one from each species of wildlife. The four worms were identified as T. callipaeda by their morphological characteristics; species identification was confirmed by PCR amplification. CONCLUSIONS: To the best of our knowledge, this is the first report of T. callipaeda infection in P. okadai as well as in a variety of wildlife, including giant panda, in nature reserves in China. These results indicate that there is a transmission cycle of T. callipaeda among wildlife in these nature reserves. The increasing number of case reports of thelaziosis in wildlife suggest a likely risk of T. callipaeda infection for the inhabitants of villages situated around nature reserves.

Globalisation and Ocular Parasitic Infections: A Review of Recent Studies.

Ocular parasitic infections, which lead to significant morbidity and mortality in particular areas, have been shifting from endemic areas to other regions due to tourism, wars and migrations in recent years. This study aimed to review the parasitic factors related to the human eye and their geographical distribution, pathogenesis of the disease and the methods used in and studies conducted for its diagnosis. PubMed, MEDLINE and Google databases were researched and reviewed for relevant keywords in recent publications. Although such parasitic infections are rare in many parts of the world, they continue to be an important public health problem that affects human and animal health in places with poor health conditions. The distribution of ocular parasites and their spread to non-endemic areas are facilitated. The morbidity and mortality risks have been increasing due to the difficulties encountered by health personnel in the diagnosis of these parasitic infections. Defining them accurately and appropriately can save not only eyesight but also lives.

[Case report: Two patients with eye worm and recurrent swelling of the extremities].

We report two cases of Loa loa (eye worm) infection in Iceland; the former in a 35-year-old woman born in Africa but living in Iceland for several years; the latter in a 31-year- old woman who had traveled in Africa. Both women sought medical attention due to discomfort in one eye. On exami-nation a worm was noted in both cases, moving under the conjunctiva, 3 cm in length and 0.5 mm in diameter. Both patients also had symptoms from the extremities; episodic swelling and itching in the former case, and muscle pain in the latter. Both patients were diagnosed with loiasis with Calabar swellings of the extremities and were successfully treated with albendazole and diethylcarbamazine. Increased awareness is needed for infections which previously have been rare in the Nordics.

Detection of Thelazia callipaeda in Phortica variegata and spread of canine thelaziosis to new areas in Spain.

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.

Competence of Phortica variegata from the United States as an Intermediate Host of the Thelazia callipaeda Eyeworm.

Over the past 20 years, Thelazia callipaeda (the oriental eyeworm) has become endemic in Europe, infecting domestic and wild carnivores and humans. The vector of this nematode, the fruit fly Phortica variegata, has recently been discovered in the United States, and its vector competence is demonstrated for T. callipaeda in this article, therefore representing a potential new threat for infection of carnivores and humans in the United States.

Spreading of Thelazia callipaeda in Greece.

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.

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.

Ocular Filariasis in US Residents, Returning Travelers, and Expatriates.

Several factors acting in concert now place US residents, returning travelers, and expatriates at risks of contracting ocular filariasis including increasing seroprevalence rates of zoonotic filariasis, international travel bringing tourists to and expatriates from filariasis-endemic regions, and warming temperatures extending distribution ranges of arthropod vectors. To describe the epidemiology and outcomes of ocular filariasis and to recommend strategies for the diagnosis, management, and prevention of ocular filariasis, internet search engines were queried with the key words in order to examine case reports and series of ocular filariasis in the US and elsewhere. Descriptive epidemiological, morphological, and molecular evidence now support increasing cases of ocular filariasis in domestic and wild animals and humans, with most cases caused by filarial worms including Dirofilaria repens and other zoonotic Dirofilaria species and Onchocerca lupi and other zoonotic Onchocerca species. Clinicians should maintain early suspicion of ocular filariasis in US residents, returning travelers, and expatriates who complain of combinations of red eye, eye pain, foreign body sensation, reduced visual acuity, and migrating ocular worms, even without significant peripheral eosinophilia or microfilaremia. Microfilariae of Wuchereria bancrofti, Brugia malayi, and O. volvulus may traverse the eye, but can usually be treated medically. Mobile adult worms trapped in the subconjunctiva or anterior chamber should be removed by ophthalmologists to permit species identification, prevent posterior uveitis and iritis, and stop worm migration into the posterior chamber which could require lens removal and vitrectomy for worm extraction causing further eye damage.

The eyes have it: long-distance dispersal by an intraorbital leech parasite of birds.

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.

Biomphalaria straminea and Biomphalaria glabrata (Mollusca: Planorbidae) as new intermediate hosts of the fish eyefluke Austrodiplostomum compactum (Trematoda: Diplostomidae) in Brazil.

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.

Orbital parasitosis.

Orbital parasitoses are uncommon diseases. Due to specific characteristics of orbital space, many different diseases, such as tumors and inflammatory disease, can present with similar clinical manifestations. The aim of this study is to review the most important clinical, epidemiological, and treatment aspects of orbital parasitoses described worldwide.

Substratum preference of Philophthalmus sp. cercariae for cyst formation under natural and experimental conditions.

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.

Survey of Phortica drosophilid flies within and outside of a recently identified transmission area of the eye worm Thelazia callipaeda in Switzerland.

Phortica drosophilid flies are the intermediate hosts and vectors of the eye worm Thelazia callipaeda. This nematode originates from Asia and was first detected in southern Europe in 1989. The aim of the study was to assess the presence and the population dynamics of Phortica flies in a recently discovered new endemic area (Ticino, Southern Switzerland, south of the Alps) of T. callipaeda (site 1), at its border (site 2), at higher altitudes (beyond 1100 meters above sea level) within (site 3) or outside (site 4) the endemic area, and in a site north of the Alps (site 5). Flies were captured using two types of fruit-baited traps, the bait being changed once per week, and by netting around the eyes of a dog and human. A total of 1695 Phortica flies were collected. One of the fruit-baited traps, which can easily be assembled with cheap components, was found to be efficient for catching Phortica spp. At site 1, 644 such flies were collected with this trap during 34 weekly catches from April to October. The number of flies caught was highest at site 2 (n=903) and it was significantly lower (n=36) at site 5 north of the Alps. Virtually no Phortica at all were caught at higher altitudes (sites 3 and 4). Females were all in all predominant in the traps, accounting for 72.6% of Phortica flies (1150/1584), although males became dominant late in the season (male/female ratio 1.26 in October). In contrast, 80.2% of Phortica flies collected around the eyes of dog and human baits by netting (n=111) were males. No female at all was captured by netting until September. PCR for T. callipaeda was negative with all Phortica flies. Morphological examination of the 523 male flies based on features of the eye margin and the number of particular genital sensilla identified 89.1% P. semivirgo, 5.7% P. variegata but also 5.2% intermediate forms. Genetic analyses of partial mitochondrial cox1 and rDNA internal transcribed spacer 1 sequences revealed that these three morphotypes were genetically not distinguishable. This study confirms the presence of Phortica spp. north to the Alps and therefore the potential risk of T. callipaeda infection outside the currently known endemic region, depending on local abundance and longevity of the drosophilid vectors.

Local transmission of the eye worm Thelazia callipaeda in southern Germany.

This report describes the first assumed locally transmitted case of the eye worm Thelazia callipaeda in a dog living in southern Germany. A 4-year-old male golden retriever from the town of Bühl in north eastern Baden-Württemberg, about 10 km from the German-French border, showed one sided lacrimation for over 2 weeks. Despite the application of antibiotics, there was no improvement, and the dog additionally showed blepharospasmus, epiphora and red conjunctivas. A deepened eye inspection revealed five whitish filiform parasites that were morphologically identified as T. callipaeda. The partial sequence of the mitochondrial cytochrome c oxidase subunit 1 gene (cox1, 605 bp) from one specimen revealed a novel haplotype, which differs by 1.3% from the only one (haplotype 1) identified in Europe so far. Since the infected dog had never been abroad with the exception of two daytrips to the close Alsace region in France, the transmission of T. callipaeda most probably was domestic. With the presence of end hosts and Phortica flies nourishing on lachrymal secretions acting as intermediate hosts and an increasing number of dogs travelling to and coming from endemic regions in the South, the establishment of T. callipaeda in large parts of Europe cannot be excluded.

Phortica variegata as an intermediate host of Thelazia callipaeda under natural conditions: evidence for pathogen transmission by a male arthropod vector.

Knowledge about Phortica variegata (Drosophilidae, Steganinae), the intermediate host of the eyeworm Thelazia callipaeda (Spirurida, Thelaziidae), is confined to experimental studies. To investigate the role P. variegata plays in the transmission of T. callipaeda under natural conditions, the population dynamics of these flies in the natural environment and their feeding preferences (on vegetables and/or animal lachrymal secretions) were examined. From April to November 2005, a total number of 969 (557 males and 412 females) P. variegata flies were collected weekly in a region of southern Italy with a history of canine thelaziosis. The flies were identified and dissected or subjected to a PCR assay specific for a region within the ribosomal ITS-1 DNA of T. callipaeda. The zoophilic preferences of P. variegata were assessed by collecting flies around the eyes of a person or around a fruit bait. Seven hundred and twenty flies (398 males and 322 females) were dissected under a stereomicroscope; 249 flies (158 males and 91 females) that died prior to the dissection were subjected to molecular investigation. Only P. variegata males were infected with larval T. callipaeda both at dissection (six, 0.83%) and with the specific PCR (seven, 2.81%), representing a total percentage of 1.34% flies infected. Interestingly, only males were collected around the eyes, compared with a male/female ratio of 1:4 around the fruit. This survey indicated that P. variegata males act as intermediate hosts of T. callipaeda under natural conditions in Europe. Both the zoophilic behaviour of P. variegata males on lachrymal secretions and their role as vector of T. callipaeda have been discussed as they represent a peculiarity in medical and veterinary entomology. The synchrony between the fly population dynamics and the biology of the nematode in the definitive host provides an interesting model for exploring the co-evolution of Thelazia spp. with their hosts.

Nematode biology and larval development of Thelazia callipaeda (Spirurida, Thelaziidae) in the drosophilid intermediate host in Europe and China.

Thelazia callipaeda, commonly known as the 'oriental eyeworm', has been recently reported in Italy and other European countries. The insect/s that act as intermediate hosts and details of larval development inside the vector remain unclear. In order to (1) demonstrate the species of fly that may act as vector/s for T. callipaeda in southern Italy (Site A) and China (Site B) and (2) describe the larval development of the nematode in the body of flies, 847 Phortica (Drosophilidae) flies were collected from the above two sites, each with a history of human and/or canine thelaziosis. Flies were identified as Phortica variegata (245 - site A) and Phortica okadai (602 - site B), experimentally infected by 1st-stage larvae (L1), kept at different temperatures and dissected daily until day 180 post-infection (p.i.). Dead flies from site A were subjected to specific polymerase chain reaction (PCR) assay to detect T. callipaeda. To demonstrate the role of Phortica as vectors of T. callipaeda, 3rd-stage larvae (L3) recovered from the proboscis of flies were deposited onto the cornea of the eyes of dogs and rabbits. Following dissection, 3 (2.9%) of P. variegata in site A were found to be infected by L3 in the proboscis on days +14, +21 and +53 p.i., compared with 26 (18.4%) of Phortica flies recorded as being positive by PCR. Sequences from positive PCR products were 99% identical to sequences of the corresponding species available in GenBank (AY207464). At site B, 106 (17.6%) of 602 dissected P. okadai were found to be infected by T. callipaeda larvae (different stages) and in total 62 L3 were recovered from the proboscis of 34 (5.6%) flies. The shortest time in which L3 were found was at day +14, +17, +19, and +50 p.i. respectively, depending on the environmental temperatures. Of 30 flies overwintered for 6 months, 6 L3 were detected at day +180 p.i. in 3 flies (10%). The biology of larval development was reconstructed on the basis of the dissection of 602 P. okadai-infected flies and the morphology of larval stages in the insect body described. The present work provides evidence that P. variegata and P. okadai act as vectors for T. callipaeda in southern Europe and in China, respectively. The phenomenon of overwintering is described here for the first time for T. callipaeda and discussed. Finally, the relationship between T. callipaeda and its fly vector is considered in light of disease prophylaxis and to model its dissemination into habitats and environments favourable to Phortica flies.