Genetic relatedness and diversity of Capillaria species infecting bayad (Bagrus bajad) in upper Egypt.

BACKGROUND: This study investigates the genetic characteristics of Capillaria isolates from the infected fish, Bagrus bajad, and their relation to human Capillaria philippinensis using Random Amplified Polymorphic DNA (RAPD-PCR) analysis. Fifteen fish Capillaria were isolated and compared to identified human C. philippinensis using six primers: M-are, M-1, G-7, G-11, G-15, and G-18. RESULTS: All six primers successfully amplified DNA, highlighting their efficacy in distinguishing between human and fish Capillaria isolates. The analysis revealed distinctive banding patterns between fish and human isolates, with variations in size and number of DNA fragments. Additionally, genetic similarity analysis showed intriguing patterns of relatedness, with certain pairs exhibiting high similarity percentages. Comparative assessment of RAPD polymorphism demonstrated consistent findings of 100% polymorphism across all primers. The Unweighted Pair Group Method with Arithmetic Mean Algorithm (UPGMA) evaluated the closest relationship between human and fish isolates. These results underscore the utility of RAPD analysis in delineating the genetic diversity among Capillaria isolates from different hosts. CONCLUSION: Overall, this study contributes to our understanding of the genetic variability and relatedness among Capillaria isolates, shedding light on their evolutionary dynamics and zoonotic potential.

The diagnostic conundrum of hyper eosinophilia-Sheer tenacity of a parasite.

We present an interesting and rare case of Capillaria hepatica infection in a 2-year-old boy, who presented with fever, rash, hepatomegaly and peripheral eosinophilia. FNAC of hepatic lesion showed parasitic eggs and PCR from the aspirate confirmed the diagnosis. We describe the cytomorphological features and provide educational multiple-choice questions related to the topic.

First report of Paracapillaria philippinensis infection in flowerhorn cichlid in India.

The flowerhorn cichlid is a popular ornamental fish in many Asian countries. The present study reports the occurrence of Paracapillaria philippinensis (Chitwood et al., 1968), a parasitic nematode in flowerhorn cichlid (Cichlasoma sp.) from south India. The infected fish demonstrated clinical symptoms viz. dark coloration, poor appetite, lethargy, erratic swimming, and white stringy faeces. Microscopic observation of the intestinal content and faeces revealed the presence of adult worms, larvae, and unembryonated eggs. PCR amplification of eukaryotic 18S rRNA, P. philippinensis-specific SSU rRNA gene, and the subsequent sequence analysis confirmed the species identity as P. philippinensis. The generated sequences were submitted in the GenBank, NCBI, under the accession numbers, MK895507.1, MK895446.1, MW144993.1, and OR685675.1. This is the first scientific report of P. philippinensis in fish from India, and it confirms that the flowerhorn cichlid can act as a definitive host for P. philippinensis. This report alerts fish handlers and enthusiasts to undertake suitable precautionary measures while handling live flowerhorn cichlids to prevent possible transmission of P. Philippinensis, which has the potential to infect humans causing intestinal capillariasis.

Regulatory mechanisms of Capillaria hepatica infection on Brandt's Vole (Lasiopodomys brandtii) population.

Parasite infection not only triggers the immune response of the host but also potentially affects the reproductive status, thereby influencing the population size. Therefore, understanding the impact of parasite infection on host immune and reproductive systems has long been an important issue in ecological research. To address this, we conducted field surveys (2021-2023) to investigate Capillaria hepatica infection status in Brandt's vole (Lasiopodomys brandtii) and performed controlled experiments in semi-natural enclosures and indoor laboratories. The results showed a negative correlation between the population size of Brandt's vole and the infection rate. To further explore the regulatory mechanisms, transcriptomic and proteomic analyses were performed on the infected BALB/c mice. The study found that post-infection with Capillaria hepatica, up-regulated genes and proteins in the mice liver were primarily associated with immune functions, while down-regulated genes and proteins were related to metabolic functions such as retinol metabolism. Through validation experiments supplementing retinol to the host infected with Capillaria hepatica, it was found that infection with Capillaria hepatica leads to a decrease in systemic available retinol levels, disrupting the expression of the hypothalamic-pituitary-gonadal (HPG) axis hormones, affecting the expression of CYP17A1, thereby regulating testosterone secretion related to spermatogenesis. This process results in abnormal spermatogenesis in the testes, thereby impacting the reproductive capacity of mice. This suggests that Capillaria hepatica regulates resource allocation in hosts, striking a "trade-off" between reproduction and survival, thereby exerting control over population size. These discoveries are crucial for comprehending the interaction between Capillaria hepatica and hosts, as well as their impacts on host reproduction and immune systems, and provide a scientific basis for controlling the transmission of Capillaria hepatica.

Eimerian and capillariid infection in farmed ring-necked pheasants (Phasianus colchicus karpowi) in Ehime, Japan, with special reference to their phylogenetic relationships with congeners.

We performed a parasitological examination of the gastrointestinal tract of farmed ring-necked pheasants (Phasianus colchicus karpowi) on two farms in Ehime, Japan. Fecal examination through flotation and sedimentation methods (43, 103, and 50 samples in three consecutive years from 2020, respectively) detected coccidian oocysts (5-58%), or capillarid (40-56%) and heterakid eggs (45-72%). Following artificial sporology, most sporulated coccidian oocysts were ellipsoidal without micropyle nor residuum, but with 1-3 polar refractile granules, morphologically reminiscent of Eimeria phasiani (Apicomplexa: Eucoccidiorida: Eimeriidae). Intensive sequencing of mitochondrial cytochrome c oxidase subunit I gene (cox-1) using pan-eimerian primers and multiple oocyst samples from different pheasants indicated a single species. We characterized, for the first time, the cox-1 sequence of E. phasiani, known to be prevalent in wild and captive ring-necked pheasants worldwide. Worm recovery under a dissection microscope revealed two capillariid and one heterakid nematode species: Eucoleus perforans (Nematoda: Trichocephalida: Capillariidae) in the esophageal epithelium (prevalence, 8-73%), Capillaria phasianina (Capillariidae) in the cecal mucosa (10-87%), and Heterakis gallinarum (Nematoda: Ascaridida: Heterakidae) in the cecal lumen (69-88%). The small subunit ribosomal RNA gene (SSU rDNA) of E. perforans was perfectly identical to that in a previous isolate from farmed Japanese green pheasants (Phasianus colchicus versicolor) at a distant locality in Japan. The SSU rDNA of C. phasianina was characterized, for the first time, demonstrating a sister relationship with Capillaria anatis, parasites found in the ceca of domestic ducks, geese, and various wild anatid birds.

Efficacy of levamisole, ivermectin and moxidectin against Capillaria spp. in European hedgehogs (Erinaceus europaeus).

This randomised study aimed to assess and compare the efficacy of treatment protocols containing levamisole, ivermectin, or moxidectin against Capillaria spp. in naturally infected European hedgehogs (Erinaceus europaeus) presented to a British wildlife rehabilitation centre. Faecal analysis, consisting of wet mount and flotation, was performed for 229 hedgehogs weighing ≥200g. Animals testing positive for Capillaria spp. (81%), excluding pregnant females, were randomly allocated a treatment protocol. Initially, hedgehogs (n = 50) received one of six 'pilot' protocols, whereas the remaining animals (n = 97) received one of three 'main' protocols. Faecal analysis was repeated on day 8 and day 12 after treatment initiation. Efficacy of each treatment was assessed based on Capillaria reduction rate (CRR), weight gain, presence of respiratory clinical signs, and outcome. Pilot protocols containing only moxidectin had a significantly lower CRR (≥28.1%) compared to those with levamisole or ivermectin (≥86.6%), whereas the main protocols containing levamisole had a significantly higher CRR (≥93.0%) compared to those containing only ivermectin (≥69.3%). Clinical parameters did not differ significantly between treatments, but animals with respiratory clinical signs at the end of the trial were significantly more likely to have lower CRR and test positive for Crenosoma striatum. C. striatum often appeared refractory to treatment, and managing these infections requires additional anthelmintic therapy. Based on the formulations and dosages trialled, moxidectin is not recommended for treating capillariosis in European hedgehogs, whereas levamisole given orally for two consecutive days at 25-35 mg/kg is suggested as the treatment of choice.

An unexpected cause of dysuria in a cat in Poland.

BACKGROUND: Urinary tract infestation by Capillaria spp. in domestic cats is rather rare, but can cause clinical symptoms and affect behaviour. To our knowledge, this report is the first to describe a case of urinary capillariosis in a cat in Poland. CASE PRESENTATION: A female formerly stray cat aged about 1.5 years showing dysuria, stranguria, periuria and lethargy was presented at the veterinary clinic. Urinalysis revealed the presence of Capillaria plica eggs in the sediment. The cat was treated successfully with three topical doses of Broadline (Merial, Toulouse, France). CONCLUSIONS: C. plica is a nematode whose definitive hosts are carnivores, which are infected by eating earthworms (the intermediate hosts). Thus, C. plica infestation is more frequent in wild carnivores and dogs, and rare in cats. Symptomatic bladder capillariosis in cats is very rarely diagnosed and described.

First description of Eucoleus garfiai (Gallego and Mas-Coma, 1975) in wild boar (Sus scrofa) in Italy.

Eucoleus garfiai (syn. Capillaria garfiai) is a nematode infecting lingual tissue of domestic and wild swine. Prevalence data for this parasite are scant and often related to accidental findings, occurring only in Japan and a few European countries. In this study, an epidemiological survey was performed in order to identify E. garfiai in wild boar from the Campania region, southern Italy. A total of 153 wild boar carcasses were inspected over the course of two hunting seasons (2019-2020). Histological examinations were performed on tongue samples fixed and stained with haematoxylin and eosin. The scraping of dorsal tongue tissue was carried out to collect adult worms for parasitological examination. Out of 153 wild boars, 40 (26.1%, 95% CI: 19.8-33.6%) tested positive for helminths and/or eggs in tongue tissues. Parasites were identified morphologically and identification was confirmed by molecular analysis of the 18S rRNA gene, showing a 99% nucleotide match with E. garfiai sequences available in literature. No statistically significant differences were found according to age, sex nor hunting province. Our findings agree with previous histopathological data confirming the low pathogenic impact of this nematode. The present study represents the first report of E. garfiai in wild boar from Italy.

Variability of Calodium hepaticum eggs from sigmodontine host species through geometric morphometric analysis.

Calodium hepaticum is a zoonotic nematode with a worldwide distribution. Although the host range of C. hepaticum includes a wide spectrum of mammals (including humans), this parasite is predominantly associated with the families Muridae and Cricetidae. Several Sigmodontinae species from Argentina were found to be infected by C. hepaticum, with a high prevalence in Akodon azarae. The present study focuses on C. hepaticum eggs from natural infection of three species of sigmodontine rodents from Argentina. Eggs were genetically characterized (intergenic 18S rRNA region). The objectives of this work are: (i) to propose a new analytical methodology; and (ii) to morphologically characterize C. hepaticum eggs, from three Sigmodontinae species (A. azarae, Calomys callidus and Oligoryzomys flavescens). Analyses were made by the Computer Image Analysis System based on the new standardized measurements and geometric morphometric tools. The resulting factor maps clearly illustrate global size differences in the parasite eggs from the three Sigmodontinae species analysed. The degree of similarity between egg populations was assessed through pairwise Mahalanobis distances, showing that the largest distances were detected between parasite eggs from C. callidus and O. flavescens. Herein, the phenotypical plasticity of C. hepaticum eggs is shown. Significant positive correlations were obtained between each egg parasite principal component 1 and rodent corporal characteristics: weight; liver weight; rodent length; and rodent body condition. The usefulness of the geometric morphometric analysis in studies of the relationship between C. hepaticum and its host must be highlighted. The high prevalence observed in A. azarae, associated with the wide size range of the parasite eggs evidenced by principal component analysis, suggests A. azarae to be the Sigmodontinae host species that plays the most important role as reservoir host for C. hepaticum in the New World.

Hepatic Capillaria hepatica (Bancroft, 1893) infection in cat (Felis catus)-histopathological findings and first report from Iran.

Capillaria hepatica (syn. Calodium hepaticum) is a globally distributed nematode with a high affinity to the liver of a wide range of mammalian hosts, including humans. Documented reports of the nematode in cats and associated histopathology are rare. Here, we describe a case of C. hepatica infection in a 5-year-old male stray cat from Iran. At post-car accident necropsy, all body parts appeared normal except for the liver, in which a few yellowish-white granulomatous nodules were observed through the capsule and in the organ. Histopathological examination of the tissue revealed a large number of clustered parasite eggs in the parenchyma. The barrel-shaped, un-embryonated eggs (55.19 × 28.37 µm), with inconspicuous caps at both ends, were covered with striated shells. The presence of ova in the liver tissue had resulted in the development of hepatic inflammation with hepatocellular necrosis associated with the development of multifocal granulomas. As predators of small rodents, the cats might have a significant role in the epidemiology of C. hepatica. Infection of hosts through ingestion of embryonated eggs in contaminated water, food, or soil is of major importance in the epidemiology of C. hepatica. Since the rare reports of feline infection have come mainly from accidental detection of the parasite, any hepatic disease presenting difficulties to find an etiological agent may virtually be associated with the infection with this little-known nematode.

Gastroenteric parasite of wild Galliformes in the Italian Alps: implication for conservation management.

This study provides insights about the diversity, prevalence and distribution of alpine wild galliformes gastrointestinal parasite community, trying to fill a gap in the scientific information currently available in scientific literature. The analysis included three host species: 77 rock partridge (Alectoris graeca saxatilis), 83 black grouse (Tetrao tetrix tetrix) and 26 rock ptarmigan (Lagopus muta helveticus) shot during the hunting seasons 2008-2015. Parasites isolated were Ascaridia compar, Capillaria caudinflata and cestodes. The rock ptarmigan was free from gastrointestinal parasites, whereas the most prevalent helminth (37%) was A. compar in both black grouse and rock partridge. C. caudinflata occurrence was significantly higher in black grouse (prevalence = 10%, mean abundance = 0.6 parasites/sampled animal) than in rock partridge (prevalence = 1.20%, mean abundance = 0.01 parasites/sampled animal). Significant differences were detected among hunting districts. A. compar was found with a significant higher degree of infestation in the hunting districts in the northern part of the study area whereas cestodes abundance was higher in Lanzo Valley. Quantitative analysis of risk factors was carried out using a generalized linear model (GLM) only on the most common parasite (A. compar). Latitude was the only factors associated with infestation risk (OR = 52.4). This study provides information on the composition and variability of the parasite community in the alpine Galliformes species.

Ecto- and endoparasites of the King's skink (Egernia kingii) on Penguin Island.

Wildlife species are often host to a diversity of parasites, but our knowledge of their diversity and ecology is extremely limited, especially for reptiles. Little is known about the host-parasite ecology of the Australian lizard, the King's skink (Egernia kingii). In spring of 2015, we carried out a field-based study of a population of King's skinks on Penguin Island (Western Australia). We documented five species of parasites, including two ectoparasitic mites (an undescribed laelapid mite and Mesolaelaps australiensis), an undescribed coccidia species, and two nematode species (Pharyngodon tiliquae and Capillaria sp.). The laelapid mite was the most abundant parasite, infesting 46.9% of the 113 captured lizards. This mite species increased in prevalence and abundance over the course of the study. Infection patterns of both mites varied with lizard life-stage; sub-adults were more commonly infested with laelapid mites than adults or juveniles, and sub-adults and adults were infested by more laelapid mites than juveniles. By contrast, adults had a higher prevalence of M. australiensis than juveniles or sub-adults. Among the gastrointestinal parasites, P. tiliquae was relatively common among the sampled lizards (35.3%). These results give new important information about reptiles as parasite hosts and what factors influence infection patterns.

Integrated taxonomic approaches to seven species of capillariid nematodes (Nematoda: Trichocephalida: Trichinelloidea) in poultry from Japan and Indonesia, with special reference to their 18S rDNA phylogenetic relationships.

Morphological and genetic analyses were performed on seven species of the family Capillariidae (Nematoda: Trichocephalida: Trichinelloidea), viz. Eucoleus perforans, Eucoleus contortus, Aonchotheca bursata, Baruscapillaria obsignata, Capillaria anatis, Capillaria phasianina, and Capillaria spinulosa, detected in poultry from Japan and Indonesia. Two Eucoleus spp., perforating the esophageal mucosa of the Japanese green pheasant farmed in Japan (E. perforans) and domestic goose in Indonesia (E. contortus), were morphologically characterized. Furthermore, we observed substantial nucleotide differences between their 18S ribosomal RNA gene (rDNA), revealing maximum identity (97.27%) over the 1797-bp length. Similarly, B. obsignata in the small intestine of Japanese green pheasants in Japan, a chicken, geese, domestic pigeons, and a turkey in Indonesia, and C. anatis in the ceca of chickens in Indonesia were morphologically and molecular-genetically compared with previously reported isolates of these species in Japan. Aonchotheca bursata collected from the small intestine of the Japanese green pheasant was also molecular-genetically characterized for the first time; however, sequencing of the 18S rDNA of C. phasianina from the cecum of the same bird was unsuccessful. Capillaria worms in the ceca of a domestic duck and geese in Indonesia were identified as C. spinulosa, which had only previously been recorded in wild birds of the Anseriformes in the Palaearctic region. Morphologically, this species was closest to Capillaria pudendotecta recorded from the ceca of wild and captive swans, except for the lack of vaginal appendages in female worms and shorter esophagi relative to the body length in both male and female worms. Phylogenetically, these two species were closely related, although substantial nucleotide changes were noted. The 18S rDNA nucleotide sequences of the species isolated here were consistent with the recent taxonomic system established for Capillariidae based primarily on the morphology of male caudal ends.

Discovery of two highly divergent negative-sense RNA viruses associated with the parasitic nematode, Capillaria hepatica, in wild Mus musculus from New York City.

Recent advances in high-throughput sequencing technology have led to a rapid expansion in the number of viral sequences associated with samples from vertebrates, invertebrates and environmental samples. Accurate host identification can be difficult in assays of complex samples that contain more than one potential host. Using unbiased metagenomic sequencing, we investigated wild house mice (Mus musculus) and brown rats (Rattus norvegicus) from New York City to determine the aetiology of liver disease. Light microscopy was used to characterize liver disease, and fluorescent microscopy with in situ hybridization was employed to identify viral cell tropism. Sequences representing two novel negative-sense RNA viruses were identified in homogenates of wild house mouse liver tissue: Amsterdam virus and Fulton virus. In situ hybridization localized viral RNA to Capillaria hepatica, a parasitic nematode that had infected the mouse liver. RNA from either virus was found within nematode adults and unembryonated eggs. Expanded PCR screening identified brown rats as a second rodent host for C. hepatica as well as both nematode-associated viruses. Our findings indicate that the current diversity of nematode-associated viruses may be underappreciated and that anatomical imaging offers an alternative to computational host assignment approaches.

Capillaria Ova and Diagnosis of Trichuris trichiura Infection in Humans by Kato-Katz Smear, Liberia.

We examined human stool samples from Liberia for soil-transmitted helminth ova by Kato-Katz smear and by quantitative PCR. Twenty-five samples were positive for Trichuris trichiura by smear but negative by quantitative PCR. Reexamination of samples showed that they contained Capillaria eggs that resemble T. trichiura in Kato-Katz smears.

Calodium hepaticum (Nematoda: Capillariidae) in wild rodent populations from Argentina.

Calodium hepaticum (Nematoda; Capillariidae) is a parasitic nematode of mammals with a cosmopolitan distribution. Adults of this nematode can infect the liver of many mammalian species, including humans, but the main hosts are members of the superfamily Muroidea. Among these, Rattus spp. have the highest apparent prevalences reported worldwide. There are only two reports of C. hepaticum infecting Sigmodontinae species (Muroidea: Cricetidae). In this survey, we examined the occurrence of C. hepaticum in two assemblages of Sigmodontinae rodents from Argentina (Santa Fe and Entre Ríos provinces). The diagnosis was made by morphological features, histopathological exam, and molecular characterization of 18S ribosomal RNA gene region. Here, we show that C. hepaticum is a common parasite of Sigmodontinae. We report the infection in six species (all new hosts): Akodon azarae, Calomys callidus, Calomys venustus, Oligoryzomys flavescens, Oligoryzomys nigripes, and Oxymycterus rufus. This is the first report of C. hepaticum in Sigmodontinae rodents from Argentina and the second record in this subfamily for South America. It is also the first confirmation of C. hepaticum infection in Sigmodontinae by molecular diagnosis. The genetic findings and the prevalences observed, together with the existing information on C. hepaticum, lead us to propose that Rattus spp. brought C. hepaticum to the New World exposing Sigmodontinae rodents, which are frequently infected by this parasite. The high prevalence of infection in A. azarae (41.2%) suggests that this host may be playing an important role in C. hepaticum dynamics in the New World.

First morphological and molecular analysis of Eucoleus boehmi like eggs in dogs from Argentina.

The canid parasites Eucoleus aerophilus (syn. Capillaria aerophila) and Eucoleus boehmi (syn. Capillaria boehmi) parasitize the lower and the upper respiratory tract, respectively. Reports and descriptions of these nematodes are scarce in Argentina, possibly due to misdiagnosis of morphologically similar trichuroids eggs, and the lack of knowledge about the species of Eucoleus in this geographical area. Scanning electron microscopy is a useful tool for identification of E. boehmi eggs based on the characteristics of the shell structure which differentiate between species. Molecular analysis complements morphological identification. Until now, there are no studies based on the analysis of E. boehmi eggs in Argentina. The aim of the present work was to study by morphological, morphometric, and molecular analysis, eggs attributable to E. boehmi isolated from dogs naturally infected in Mar del Plata city, Argentina. Eggs isolated from two dog fecal samples were analyzed by light and scanning electron microscopy. A fragment of mitochondrial DNA (mtDNA) of the cytochrome c oxidase subunit I gene (cox1) from eggs was sequenced, and phylogenetic analysis was performed in this study. According to morphological results based on the wall surface ultrastructure, the eggs studied were assigned to E. boehmi. Molecular analysis supported the morphological identification. The divergence of 9-12% with the European isolated could suggest a new geographical genetic variation of E. boehmi, but also question the possible existence of cryptic species. This is the first characterization of E. boehmi eggs in dogs from Argentina.

Immune responses induced by co-infection with Capillaria hepatica in Clonorchis sinensis-infected rats.

Clonorchis sinensis and Capillaria hepatica are zoonotic parasites that mainly infect the liver and cause serious liver disorders. However, immunological parameters induced by co-infection with these parasites remain unknown. In this study, for the first time, we investigated immunological profiles induced by co-infection with C. hepatica (CH) in C. sinensis (CS)-infected rats (Sprague-Dawley). Rats were infected primarily with 50 metacercariae of C. sinensis; 4 weeks later, they were subsequently infected with 1000 infective C. hepatica eggs. Significantly higher levels of C. sinensis- or C. hepatica-specific IgG antibodies were found in the sera of rats. Interestingly, no cross-reacting antibody was observed between C. sinensis and C. hepatica infections. Significantly raised eosinophil levels were found in the blood of C. sinensis/C. hepatica co-infected rats (CS + CH) compared to the blood of rats infected singly with C. sinensis. Co-infected rats showed significantly higher levels of lymphocyte proliferation and cytokine production compared to a single C. sinensis infection. The worm burden of C. sinensis was significantly reduced in co-infected rats compared to the single C. sinensis infection. These results indicate that the eosinophils, lymphocyte proliferation and cytokine production induced by subsequent infection with C. hepatica in C. sinensis-infected rats might contribute to the observed C. sinensis worm reduction.

Capillaria appendigera n. sp. (Nematoda: Capillariidae) from the goldbanded jobfish Pristipomoides multidens (Day) (Lutjanidae) and new records of other intestinal capillariids from marine perciform fishes off Australia.

Based on light and scanning electron microscopical studies, a new nematode parasite, Capillaria appendigera n. sp. (Capillariidae), is described from the intestine of the goldbanded jobfish Pristipomoides multidens (Day) (Perciformes, Lutjanidae) from the Arafura Sea West, off the northern coast of Australia. The new species, belonging to the subgenus Procapillaria Moravec, 1987, differs from other congeneric species from fishes mainly in the length (0.92-1.13 mm), shape and structure of the spicule, obtuse spines on the spicule sheath and the structure of eggs. It is characterised, in the male, by the presence of two well-developed dorsolateral caudal lobes, a pair of lateral papillae, a heavily sclerotised spicule with many rough transverse grooves covering almost the entice spicule surface (except for spicule ends), a spinose spicule sheath, and in the female, by a subterminal anus, mostly the presence of a large vulval appendage and by eggs (size 54-69 × 27-33 µm) encapsulated by a conspicuous light-coloured superficial layer. Capillaria appendigera n. sp. is the 12th nominal species of capillariids recorded from fishes in Australian waters and the second known capillariid species parasitising fishes of the perciform family Lutjanidae. In addition, four unidentifiable, morphologically different types of capillariid females, probably representing undescribed species, were recorded from the intestines of marine fishes off the northern coast of Australia: Capillariidae gen. sp. 1 and Capillariidae gen. sp. 2 from Lutjanus johnii (Bloch) and L. malabaricus (Bloch & Schneider), respectively (both Lutjanidae), Capillariidae gen. sp. 3 from Protonibea diacanthus (Lacépède) (Sciaenidae) and Capillariidae gen. sp. 4 from Rachycentron canadum (Linnaeus) (Rachycentridae).