Spirurid Nematodes Research Articles

Further studies on the diversity of Cylicospirura Vevers, 1922 (Nematoda: Spirocercidae) in African carnivores, with description of a new species.

Cylicospirura Vevers, 1922 is a genus of gastrointestinal spirurid nematodes parasitizing mainly felid but also canid, hyaenid and dasyurid hosts. Presently, 11 species are recognized worldwide, of which 4, Cylicospirura subaequalis, Cylicospirura felinea, Cylicospirura crocutae and Cylicospirura pardalis, have been recorded from African carnivores. In the present study, we describe Cylicospirura phiri n. sp. from hyaenas, namely Crocuta crocuta (type host) in Zimbabwe and Hyaena hyaena in Cameroon. The new species is the second species in the genus with bicuspid teeth. Furthermore, it can be distinguished from its congeners by a combination of characters, such as the absence of accessory teeth, the length and shape of the muscular oesophagus, position of the nerve ring, deirids and excretory pore in relation to the muscular oesophagus, the position of the vulva, spicule length and the shape of the female tail. Additionally, based on new material, detailed morphological descriptions are provided for C. crocutae and C. pardalis whose original descriptions were based on fragmented material. The material from Felis lybica, currently deposited as C. subaequalis, is described as C. felinea. First-time scanning electron micrographs are presented for the 4 species confirmed in African carnivores.

Pterygodermatites (Mesopectines) whartoni (Nematoda: Rictulariidae) encysted larvae in invasive Cuban treefrogs (Osteopilus septentrionalis) from Florida, United States.

Species of Pterygodermatites are spirurid nematodes that have expanded their geographic distribution worldwide. They infect a variety of mammalian definitive hosts with few reports of potential paratenic infections in amphibian and reptile hosts. In this study, we report Pterygodermatites sp. larvae identified in free-ranging, invasive Cuban treefrogs (Osteopilus septentrionalis), from central Florida, United States. Encysted larvae were recovered from the skeletal muscle and/or the coelomic cavity of three frogs; molecular characterization of the small subunit (18S) ribosomal RNA and cytochrome oxidase I genes of the parasites matched reported sequences of Pterygodermatites (Mesopectines) whartoni (Tubangui, 1931). This is a parasite native to Southeastern Asia and to the best of the authors' knowledge, it is the first report of the species in the New World. The recovery of invasive Pterygodermatites from invasive Cuban treefrogs in North America highlights the growing concern regarding the potential impact non-native parasites and invasive species may have on native wildlife populations.

Case Report: Onchocerciasis (Loa Loa)

Onchocerca volvulus is a spirurid nematode from the Superfamily Filarial diseases, family Onchocerciadae. We report a family member from Saudi Arabia with Onchocerciasis from Dammam City.We report a family member from Saudi Arabia with Onchocerciasis from Dammam City. Ocular lesions, ranging from sclerosing keratitis to optic nerve atrophy, increase the incidence of Blindness among patients.Knowledge about tropical diseases in non-tropical countries is essential to early diagnosis and treatment.

Morphologic and Genetic Characterization of Protospirura canariensis n. sp. (Nematoda, Spiruridae), a Parasite of the Black Rat Rattus rattus (Rodentia, Muridae) from El Hierro Island (Canary Archipelago, Spain)

A new spirurid nematode, Protospirura canariensis n. sp., a parasite of the black rat Rattus rattus Linnaeus, 1758 (Rodentia: Muridae), in El Hierro Island (Canary Archipelago, Spain), was described by means of light (LM) and scanning electron microscopy (SEM). The most discriminating characteristics between the new species and the remaining species of the genus Protospirura were observed to be the following: (a) the number of tooth-like outgrowths in the sub-median and lateral lobes of the pseudolabia, both in males and females (2 and 4, respectively); (b) the size of the right and left spicules in males (643–715 µm and 309–412 µm, respectively); and (c) the numbers and arrangements of the cloacal papillae in males. The new species has a total of 17 cloacal papillae (4 large and pedunculated pairs of precloacal papillae, an unpaired precloacal papilla and 4 pairs of postcloacal papillae). The arrangement of the postcloacal papillae are as follows: the first pair are large, pedunculated and placed near the posterior edge of cloaca; the three remaining postcloacal pairs are grouped and located near the posterior tip. In the latter group, the papillae in the first pair are large and pedunculated. The parasitized hosts and their geographical distributions were also useful criteria in distinguishing P. canariensis n. sp. from the remaining species of the genus Protospirura. In addition, the cytochrome c oxidase subunit I (cox1) sequence of the new species was obtained and compared with the available data of related species.

Spirocerca lupi in the stomach of two Andean foxes (Lycalopex culpaeus) from Chile

The genus Spirocerca includes nematodes that parasitize the stomach and the oesophagus of carnivores, chiefly canids. Herein, we provide new data about the morphological, histopathological, and molecular characterization of Spirocerca sp. in Andean foxes (Lycalopex culpaeus) in Chile. Intact immature worms, identified as Spirocerca sp., were recovered in the lumen of the stomach from two foxes. Histologically, worms morphologically consistent with spirurid nematodes were present within the wall of the stomach and surrounded by nodular areas of inflammation with central necrotic debris. Molecular analysis of the cox1 gene yielded 19 sequences and 5 nucleotide sequence types with 99.95 to 99.98% similarity, being shared between both foxes. Nucleotide similarity ranged from 93.1 (with genotype 2 of S. lupi and S. vulpis) to 95.8% (with genotype 1 of S. lupi), a higher similarity than noted from sequences of S. lupi from an Andean fox from Peru (91.0 to 93.3%). However, the Poisson Tree Processes for species delineation did not support the existence of a new species Spirocerca. Phylogenetic and nucleotide analyses suggest that these specimens belong to a new variant or genotype of S. lupi or to a cryptic species. Whether the presence of the worms in the stomach has to do with genotypic differences in parasites or host or some combination is uncertain. Spirocerca lupi has never been found in Chilean dogs and must be investigated.

Larvae of Spirocerca lupi and another spirurid species in the same dung beetles: notes on species identification.

Various dung beetle species of the family Scarabaeidae have been reported as intermediate hosts of Spirocerca lupi from different geographical locations, but there has been no data from south-east Asian countries. In the present study in Vietnam, by using morphological and molecular approaches, we identified the third-stage larvae of S. lupi for the first time in two dung beetle species, Catharsius molossus and Copris szechouanicus, adding them as new intermediate hosts of this nematode. In addition, both beetle species were infected with larvae of another spirurid nematode of Physocephalus sp. At large magnifications above 200×, these two spirurid larvae can be differentiated from each other by their body size (1880-2662 vs. 1417-1635 μm) and detailed morphological features of the anterior and posterior ends, such as the length of the buccal cavity, the position of the nerve ring and excretory pore, and tail characters. However, it is difficult to distinguish them at a lower magnification due to their minute size. Moreover, morphometric data of S. lupi larvae vary among reports and the body length may overlap with that of Physocephalus sp., thus, misidentification may occur, indicating the necessity of careful examination for accurate identification. The findings of the present study also supposed that larvae of S. lupi and more spirurid nematodes may be concurrently found in various dung beetle species, including C. molossus and C. szechouanicus, in other south-east Asian countries. Thus, more investigations in various countries should be conducted to identify spirurid larvae from dung beetles in order to fully understand their role as intermediate hosts of S. lupi and other spirurid nematodes.

First report of Metathelazia capsulata in red foxes (Vulpes vulpes) in Europe and new contributions to its identification

Metathelazia capsulata is a lungworm that inhabit in the bronchi and bronchioles from mammal carnivore species, which life cycle is unknown. M. capsulata-like spirurid nematodes were isolated at necropsy from the respiratory tract of red foxes (Vulpes vulpes) from the Region of Murcia (SE Spain). The main objective of this study was to describe in detail the morphometric features of these nematodes, as well as to report some molecular markers. The principal morphometric difference compared to previous M. capsulata descriptions was the shorter total length for both males and females (6.6 mm and 7.4 mm, respectively). In addition, the mean values of buccal cavity depth and distance between the excretory pore and the anterior end of the nematode were also lower than those previously reported. On the other hand, sequence data of the mitochondrial (COI) and nuclear (rDNA) genes of M. capsulata were described, being the first time that molecular markers are reported for the genus Metathelazia and also for the entire family Pneumospiruridae. Based on data available from GenBank, these results indicate that M. capsulata sequences are closely related to the family Rhabdochonidae, which is assumed to belong to superfamily Thelazioidea, a superfamily including the family Pneumospiruridae, but also suggest the distant relations with the family Thelaziidae. This is the first time that M. capsulata is reported in red fox from Europe. This study provides valuable information for future phylogenetic studies on Metathelazia spp. nematodes and, in general, on species of the family Pneumospiruridae.

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

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

Summer Sores Secondary to a Hoof Crack in an Andalusian Stallion.

Cutaneous habronemosis in horses is caused by larvae of the spirurid nematodes Habronema microstoma and Habronema muscae. These lesions, also known as “summer sores’’, are often severe and disfiguring. Although Habronema-caused lesions at the coronary grooves have been described, cases of hoof cracks with secondary summer sores have never been reported. The present case describes clinic-pathological and surgical features of a quarter crack case complicated by cutaneous habronemosis at the dermal layers. A 15-year-old, Andalusian stallion was referred to the Veterinary Teaching Hospital of the University of Teramo because of a mass of the hoof and a severe lameness. The clinical examination revealed an exuberant granulation tissue protruding from a full thickness vertical quarter crack. The mass was surgically removed, and subjected to histopathological, microbiological, and parasitological analyses. A copromicroscopic examination was also performed. The feces scored PCR positive for H. muscae, while the skin for both H. microstoma and H. muscae, thus confirming the primary role of Habronema in causing the hoof mass. This is the first description of a hoof wall crack complicated by summer sores, with simultaneous gastric habronemosis. This case confirms that a prompt diagnosis during fly activity is imperative for an efficacious treatment and a timely prevention of disfiguring summer sores.

First finding of spirurid larva (Chromadorea, Spirurida) in the common European viper Vipera berus (Linnaeus, 1758) of the Russian fauna

The National park “Smolny” (Republic of Mordovia, Russia) is located in the Basin of Alatyr River, a second-order tributary of the Volga River. Favorable conditions are created for the development of helminths and infecting reptiles with them in floodplain biotopes. In 2018–2020 in this Protected Area we examined 25 individuals of the common viper Vipera berus (Linnaeus, 1758) by the method of complete helminthological dissection. We studied only road-killed vipers and reptiles killed by local residents. In total, eight species of helminths were registered in vipers: Leptophallus nigrovenosus, Telorchis assula, Alaria alata, larvae, Rhabdias fuscovenosa, Oswaldocruzia filiformis, Physocephalus sexalatus, larvae, Physaloptera clausa, larvae and Agamospirura minuta, larvae. Larva of spirurid nematodes Ph. sexalatus, Ph. clausa and A. minuta were recorded in the common viper for the first time in Russia. We found these nematode juveniles in walls and lining of stomach and intestine of snakes. We gave original drawings and morphological descriptions of these nematodes. Vipera berus was noted as a new host for Physaloptera clausa. Currently the helminth fauna of Vipera berus of the Russian fauna includes 15 species. Helminth infection of Vipera berus strongly depends on habitat and, especially, on the diet features. Snakes that live in dry habitats and feed on mouse-like rodents, as a rule, are weakly infested by helminths. Conversely, helminth infection is higher in vipers living in near-water habitats and feeding tailless amphibians. Participation of paratenic hosts in the helminth life cycles plays an important role in the distribution and preservation of parasites in the wild, and increases the invasion probability of the final hosts.

Zoonotic Thelazia californiensis in dogs from New Mexico, USA, and a review of North American cases in animals and humans.

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.

Pterygodermatites nycticebi infections in golden lion tamarins (Leontopithecus rosalia rosalia) and aye-ayes (Daubentonia madagascariensis) from a German zoo.

In a golden lion tamarin (Leontopithecus rosalia rosalia) colony kept indoors in a German zoo, two animals presented a sudden onset of reduced general condition, lethargy, and diarrhea. At animal capture for clinical examination, adult nematode stages were observed after stress-induced defecation. Despite treatment, two golden lion tamarins died in the following 2 days. At necropsy, spirurid stages were found in the lungs and intestine. Additionally, adult Pterygodermatites spp. were identified in histopathological samples of intestine and pancreas, confirming the previous diagnosis. Upon diagnosis, all animals were treated with ivermectin (0.2 mg/kg; SC). Thereafter, the general condition of the golden lion tamarins improved, whereby some of them excreted spirurid nematodes over 3 days. Four weeks after treatment, 20 fecal samples from the colony were examined and proved negative for parasitic stages. Given that common German cockroaches (Blattella germanica) are suitable intermediate hosts of Pterygodermatites nycticebi, 30 specimens were collected from seven different locations around the golden lion tamarins housing. Third-stage larvae of Pterygodermatites spp. were recovered from those cockroaches. Regular anthelmintic treatments, coprological screenings, and controls for intermediate hosts were recommended. More than 2 years later, P. nycticebi infection was diagnosed again histopathologically in an aye-aye (Daubentonia madagascariensis) which suddenly died. Coprological analysis confirmed the presence of spirurid eggs. Due to prosimian primates' cockroach-eating habits and given that total cockroach eradication proved impossible, continuous cockroach control strategies and regular treatments of primates are currently performed to prevent further P. nycticebi infections.

Some Spirurid Nematodes (Spirurida) from Freshwater and Brackish-Water Fishes in Okinawa Prefecture, Japan, with Descriptions of Two New Species.

Despite the fact that Okinawa Prefecture represents a very interesting subtropical region of Japan, its fauna of nematodes parasitizing fishes is still little-known. Therefore, new data are needed to recognize the species composition of these parasites in this zoogeographically remarkable region. Helminthological examinations of some freshwater and brackish-water fishes in Okinawa Prefecture carried out in the years 2010, 2016 and 2018, revealed two new and four insufficiently known species of spirurid nematodes (Spirurida), all gastrointestinal parasites. These were studied with the use of light and scanning electron microscopy. All nematode species recorded are described: Rhabdochonidae: Rhabdochona honshuensis Moravec et Nagasawa, 1989 from Glossogobius celebius (Valenciennes) (Gobiidae, Perciformes) (new host), Rhabdochona iriomotensis sp. nov. from Ophieleotris sp. (Eleotridae, Perciformes) and Rhabdochona sp. (only females) from Eleotris acanthopoma Bleeker and E. fusca (Forster) (both Eleotridae, Perciformes); Cystidicolidae: Spinitectus mirabilis sp. nov. from Kuhlia rupestris (Lacepède) (Kuhliidae, Perciformes) and Spinitectus sp. larvae from E. acanthopoma; and Camallanidae: Procamallanus (Spirocamallanus) sp. (fourth-stage larva) from Yongeichthys criniger (Valenciennes) (Gobiidae, Perciformes). Rhabdochona iriomotensis sp. nov. is very similar to R. honshuensis, but differs from it in the presence of well-developed ventral precloacal ridges. Spinitectus mirabilis sp. nov. differs from its congeners and all other cystidicolids in having eggs provided with both lateral swellings and polar filaments. In addition to the discovery of two new nematode species, Rhabdochona iriomotensis sp. nov. and Spinitectus mirabilis sp. nov., the findings of all other species represent new host and geographical records. Rhabdochona denudata honshuensis Moravec et Nagasawa, 1989 is elevated to the level of an independent species R. honshuensis.

New records of spirurid nematodes (Nematoda, Spirurida, Guyanemidae, Philometridae & Cystidicolidae) from marine fishes off New Caledonia, with redescriptions of two species and erection ofIchthyofilaroidesn. gen.

Recent examinations of spirurid nematodes (Spirurida) from deep-sea or coral reef marine fishes off New Caledonia, collected in the years 2006–2009, revealed the presence of the following five species: Ichthyofilaroides novaecaledoniensis (Moravec et Justine, 2009) n. gen., n. comb. (transferred from Ichthyofilaria Yamaguti, 1935) (females) (Guyanemidae) from the deep-sea fish Hoplichthys citrinus (Hoplichthyidae, Scorpaeniformes), Philometra sp. (male fourth-stage larva and mature female) (Philometridae) from Epinephelus maculatus (Serranidae, Perciformes), Ascarophis (Dentiascarophis) adioryx Machida, 1981 (female) (Cystidicolidae) from Sargocentron spiniferum (Holocentridae, Beryciformes), Ascarophis (Ascarophis) nasonis Machida, 1981 (males and females) from Naso lituratus and N. unicornis (Acanthuridae, Perciformes), and Ascarophisnema tridentatum Moravec et Justine, 2010 (female) from Gymnocranius grandoculis (Lethrinidae, Perciformes). Two species, I. novaecaledoniensis and A. nasonis, are redescribed based on light microscopical (LM) and scanning electron microscopical (SEM) examinations, the latter used in these species for the first time. Morphological data on the specimen of A. tridentatum from the new host species are provided. Philometra sp. (from E. maculatus) most probably represents a new gonad-infecting species of this genus. The newly established genus Ichthyofilaroides n. gen. is characterized mainly by the presence of a small buccal capsule and by the number and distribution of cephalic papillae in the female; it is the sixth genus in the Guyanemidae.

TRANSMISSION OF PTERYGODERMATITES NYCTICEBI IN A COLONY OF GOELDI'S MONKEYS ( CALLIMICO GOELDII) AND EVALUATION OF TREATMENT AND CONTROL.

Over a 2-yr period, four Goeldi's monkeys ( Callimico goeldii) died in a private zoo due to infections with the spirurid nematode Pterygodermatites nycticebi. Therapeutic measures with different anthelmintics were not successful. Due to the severe consequences caused by these infections, different actions were initiated, including sanitation measures and controlling of potential intermediate hosts (coprophagous arthropods). To identify possible intermediate hosts, arthropod species detected in the enclosure-parasite-free German cockroaches ( Blattella germanica), European earwigs ( Forficula auricularia), and rough woodlice ( Porcellio scaber)-were experimentally fed with feces of monkeys with patent P. nycticebi infections, resulting in established infections with third-stage larvae (L3) in roaches and earwigs. Furthermore, spiruroid L3 were detectable in 43% of the roaches and 30% of earwigs caught at the zoo. Polymerase chain reaction and sequence analysis of eggs, larval, and adult stages resulted in identical results, confirming the establishment of the parasite's life cycle in the zoo. This is the first documentation of the vector capacity of the European earwigs for P. nycticebi. As a measure of sanitation, a large part of the enclosure was emptied and cleaned. The Goeldi's monkeys were quarantined and treated with levamisole (7.5 mg/kg sc twice in intervals of 2 wk). Repeated coprologic examinations by zinc chloride flotation were undertaken. After the levamisole therapy, eggs were not found in the feces for 3 mo. However, shortly after resettling the monkeys into the sanitized enclosure, reshedding of small amounts of spirurid eggs was observed, whereupon deworming with levamisole was prescribed several times per year. The sanitation measures and the elimination of the intermediate hosts in a natural enclosure are presented as an example of the long-term controlling of the parasites.

Morphologic Observations and Novel 18S rRNA Sequences of Abbreviata hastaspicula and Abbreviata antarctica from Varanus spp. Lizards in Australia.

The nematodes Abbreviata antarctica von Linstow, 1899, and Abbreviata hastaspicula Jones, 1979 , are predominant spirurid nematodes in species of Varanus lizards in Australia. However, genetic knowledge of these two species of nematode is lacking. In this study, nematodes removed from Varanus gouldii were examined using integrated morphologic and molecular methods. We extracted DNA from A. hastaspicula and A. antarctica for PCR and sequencing. Specific 18S small subunit ribosomal RNA (rRNA) primers were designed on the basis of existing 18S rRNA sequences of Physalopterinae strains. Species of Abbreviata, which are closely similar morphologically, may be misidentified, especially the larvae of different species of Abbreviata that cannot be differentiated. The findings of this study will improve the accuracy in identification of A. hastaspicula and A. antarctica, both morphologically and molecularly.

Antechiniella septentrionalis n. sp. (Spirurida: Acuariidae), a new intestinal nematode parasite of the tundra vole Microtus oeconomus (Pallas) (Rodentia: Muridae) in the north-east of Russia.

Antechiniella septentrionalis n. sp. (Spirurida: Acuariidae) is described from the duodenum of a tundra vole, Microtus oeconomus (Pallas), collected in the Magadan region in the north-east part of Russia. It differs from A. suffodiax (Beveridge & Barker, 1975) and A. sertatum Smales, 1991 mainly in having a larger number of postcloacal papillae (5-6 pairs vs 4 pairs), a differently shaped left spicule, the disposition of precloacal papillae in two rows vs one, and oblong vs oval eggs. Other differences include the different disposition of ovaries in A. septentrionalis n. sp and A. suffodiax and the different structure of deirids in A. septentrionalis n. sp. and A. sertatum. The new species was characterized molecularly (partial sequences for 18S rRNA, 28S rRNA and cox1 mtDNA). The phylogenetic analyses performed showed the affinity of the new species to the members of the Acuariidae and other spirurid nematodes.

Gastrointestinal protists and helminths of habituated agile mangabeys (Cercocebus agilis) at Bai Hokou, Central African Republic.

Infectious diseases including those caused by parasites can be a major threat to the conservation of endangered species. There is thus a great need for studies describing parasite infections of these species in the wild. Here we present data on parasite diversity in an agile mangabey (Cercocebus agilis) group in Bai Hokou, Dzanga-Sangha Protected Areas (DSPA), Central African Republic. We coproscopically analyzed 140 mangabey fecal samples by concentration techniques (flotation and sedimentation). Agile mangabeys hosted a broad diversity of protistan parasites/commensals, namely amoebas (Entamoeba spp., Iodamoeba buetschlli), a Buxtonella-like ciliate and several parasitic helminths: strongylid and spirurid nematodes, Primasubulura sp., Enterobius sp., and Trichuris sp. Importantly, some of the detected parasite taxa might be of potential zoonotic importance, such as Entamoeba spp. and the helminths Enterobius sp., Trichuris sp., and strongylid nematodes. Detailed morphological examination of ciliate cysts found in mangabeys and comparison with cysts of Balantioides coli from domestic pigs showed no distinguishing structures, although significant differences in cyst size were recorded. Scanning or transmission electron microscopy combined with molecular taxonomy methods are needed to properly identify these ciliates. Further studies using molecular epidemiology are warranted to better understand cross-species transmission and the zoonotic potential of parasites in sympatric non-human primates and humans cohabiting DSPA.

Nematode Thelazia callipaeda is spreading across Europe. The first survey of red foxes from Slovakia.

Canine thalaziosis caused by the spirurid nematode Thelazia callipaeda has started to spread across Western and Central Europe during the last decade. In Slovakia, the first autochthonous cases of this infection were recorded in 2016 in four dogs from the south-eastern part of the country. In August 2017 other autochthonous case, again from the same locality, was reported. Seeing that red foxes are considered the main reservoir hosts for T. callipaeda, their examination could provide an integrated view of the real parasite distribution. Within the present study, 523 red foxes were examined by necropsy, and T. callipaeda nematodes were recovered from the conjunctival sacs of 7 animals, which represents an overall positivity of 1.3%. Six infected foxes originated in eastern Slovakia, which is consistent with the area where positive dogs were recently found. Also, single positive red fox was found in north-western Slovakia. Regarding morphology and morphometry, the specimens recovered from the foxes in this study were evaluated as larger in size when compared to nematodes isolated from Slovak dogs as well as dogs and foxes from other studies. BLAST analyses of the cox1 gene showed that all specimens isolated from Slovak red foxes were identified as haplotype 1 which circulated also in other European countries. Considering that majority of the infected animals, dogs and foxes, came from Košice region, we can presume that this area might become endemic in a short period of time.

Morphological and Mitochondrial Genomic Characterization of Eyeworms (Thelazia callipaeda) from Clinical Cases in Central China.

Thelazia callipaeda, also called the oriental eyeworm, is the major etiological agent of human thelaziasis. Cases of thelaziasis have increased in recent years in China. Although this species is of medical importance, the genetics and phylogenetic systematics of T. callipaeda are poorly understood. In this study, we first reported three cases of thelaziasis in central China. All clinical isolates were identified as T. callipaeda according to morphological characteristics by light microscopy and scanning electron microscopy. Next, complete mitochondrial (mt) genomes for the three T. callipaeda isolates from different geographical locations were fully characterized using an Illumina sequencing platform. In addition, all available mt genomes of spirurid nematodes in GenBank were included to reconstruct the phylogeny and to explore the evolutionary histories of the isolates. The genome features of the T. callipaeda isolates contained 12 PCGs, 22 transfer RNA genes, two ribosomal RNA genes and a major non-coding region. The mtDNA nucleotide sequences of the T. callipaeda isolates from different hosts and different locations were similar. The nad6 gene showed high sequence variability among all isolates, which is worth considering for future population genetic studies of T. callipaeda. Phylogenetic analyses based on maximum parsimony and Bayesian inference methods revealed close relationships among Thelaziidae, Onchocercidae, Setariidae, Gongylonematidae, Physalopteridae, Dracunculidae, and Philometridae. The monophyly of the T. callipaeda isolates from different hosts and distinct geographical locations was confirmed. The entire mt genomes of T. callipaeda presented in this study will serve as a useful dataset for studying the population genetics and phylogenetic relationships of Thelazia species.