Trichinella species are zoonotic nematodes that infect wild carnivores and omnivores throughout the world. We examined the prevalence and species of Trichinella infections in cougars (Puma concolor couguar) from Colorado, United States. Tongues from cougars were examined by pepsin–HCl artificial digestion to detect Trichinella spp. larvae. The species or genotype of individual worms was identified by multiplex polymerase chain reaction (PCR). Trichinella spp. larvae were detected in 17 of 39 cougars (43.6% (28.7–59.5%)). Five of the cougars (12.8%) were infected with T. murrelli, 3 (7.7%) were infected with T. pseudospiralis, and 1 (2.6%) had Trichinella genotype T6. Trichinella spp. larvae from eight cougars were not identified at the species level, due to degraded DNA. The high prevalence of Trichinella spp. in cougars from Colorado and reports of the parasite in other populations of Puma spp. suggest that this large predator is a key mammalian reservoir.

The Chinese sleeper (Perccottus glenii), an invasive Asian fish, was first registered in Germany in 2009 (westernmost extent of its invasive range). We sampled Chinese sleepers from two localities on the Bücherlgraben creek (a tributary of the River Naab) in south-eastern Germany in November 2015 and examined them for parasite infection. Twelve taxa were registered, including ciliates (unidentified Trichodina), a monogenean, three cestode species, two digenean taxa, two acanthocephalan species, two nematode species and one mollusc glochidia. Infracommunities consisted of 1–5 species, with 10% of fish uninfected. Three parasite species (Acanthocephalus anguillae, Gyrodactylus luciopercae and Pseudocapillaria tomentosa) were recorded on Chinese sleepers for the first time. The results highlight the important role of the Chinese sleeper as a second intermediate host in the life cycle of heron and grebe parasites. The Chinese sleeper parasite community displayed low homogeneity at both localities sampled, with allogenic parasites (metacercariae and mesocercoids) mostly shared. Differences between localities were mainly caused by autogenic parasites. No invasive parasites associated with the Chinese sleeper were observed in the study area, all parasites being representatives of European fauna. This supports the hypothesis of introduction via the aquarium trade or through transport with commercial fish.

Concurrent infections of helminths in vertebrates are widespread and may demonstrate synergistic, antagonistic or negligible levels of interactions between species that share a common site. However, indirect interactions between species that occur in different organs of a host are poorly documented, particularly in fish. Plerocercoids of Triaenophorus nodulosus are common liver infections of European perch (Perca fluviatilis). These larval cestodes cause extensive liver damage, resulting in systemic pathologies that include alteration of the physiochemical environment of the intestine. Perch harbour a wide range of intestinal helminths whose occurrence may be potentially influenced by the concurrent presence of T. nodulosus plerocercoids. The present study, using an existing dataset, investigated the effects of T. nodulosus on the infection levels of four common perch helminths – Acanthocephalus lucii, Camallanus lacustris, Proteocephalus percae and Bunodera luciopercae. The prevalences of A. lucii and C. lacustris were significantly reduced in fish infected by T. nodulosus, although the mean intensity of infections remained unaffected for any helminth species, while the mean abundance of C. lacustris was significantly reduced in plerocercoid-affected perch. Differences in site selection and individual interactions between the four helminth species in the intestine of T. nodulosus-infected and non-infected perch were rarely observed.

Northern bobwhite (Colinus virginianus) and scaled quail (Callipepla squamata) have experienced chronic declines within the Rolling Plains ecoregion of Texas. Parasitic infection, which has long been dismissed as a problem in quail, has not been studied thoroughly until recently. A total of 219 northern bobwhite and 101 scaled quail from Mitchell County, Texas were captured and donated from 2014 to 2015, and examined for eyeworm (Oxyspirura petrowi) and caecal worm (Aulonocephalus pennula) infections. In 2014, bobwhites averaged 19.6 ± 1.8 eyeworms and 98.6 ± 8.2 caecal worms, and 23.5 ± 2.1 eyeworms and 129.9 ± 10.7 caecal worms in 2015. Scaled quail averaged 4.8 ± 1.0 eyeworms and 50 ± 6.8 caecal worms in 2014, and 5.7 ± 1.3 eyeworms and 38.1 ± 7.1 caecal worms in 2015. This study expands the knowledge of parasitic infection in quail inhabiting the Rolling Plains of Texas. A significant difference was documented in O. petrowi infection between species but there was no significant difference in A. pennula between quail species. No significant difference was detected in parasite infection between the sexes of both northern bobwhite and scaled quail. This study also documented the highest reported O. petrowi infection in both species of quail. Additional research is needed on the life history and infection dynamics of O. petrowi and A. pennula infections to determine if there are individual- and/or population-level implications due to parasitic infection.

Synonymous codons are used with different frequencies, a phenomenon known as codon bias, which exists in many genomes and is mainly resolute by mutation and selection. To elucidate the genetic characteristics and evolutionary relationship of Wucheraria bancrofti and Schistosoma haematobium we examined the pattern of synonymous codon usage in nuclear genes of both the species. The mean overall GC contents of W. bancrofti and S. haematobium were 43.41 and 36.37%, respectively, which suggests that genes in both the species were AT rich. The value of the High Effective Number of Codons in both species suggests that codon usage bias was weak. Both species had a wide range of P3 distribution in the neutrality plot, with a significant correlation between P12 and P3. The codons were closer to the axes in correspondence analysis, suggesting that mutation pressure influenced the codon usage pattern in these species. We have identified the more frequently used codons in these species, most codons ending with an A or T. The nucleotides A/T and C/G were not proportionally used at the third position of codons, which reveals that natural selection might influence the codon usage patterns. The regression equation of P12 on P3 suggests that natural selection might have played a major role, while mutational pressure played a minor role in codon usage pattern in both species. These results form the basis of exploring the evolutionary mechanisms and the heterologous expression of medically important proteins of W. bancrofti and S. haematobium.

Terrestrial arthropods host a variety of helminth parasites, yet quantifying the intensity of infection in these hosts post-mortem is challenging because carcasses may desiccate quickly. We recovered cysticercoids of Hymenolepis diminuta from desiccated flour beetle (Tribolium confusum) carcasses by modifying a published insect rehydration procedure. Without rehydration, carcasses dissected more than 1 day post-mortem had noticeable degradation of cysticercoids. Mild rehydration (soaking in water only for 2 days, or 0.5–10% KOH for 1 h followed by 1 day in water, or 0.5% KOH for 1 day) left carcasses tough and time-consuming to dissect, but all parasites could be recovered and were similar in body size to fresh cysticercoids. Moderate rehydration (5–10% KOH for 1 day) allowed all parasites to be recovered and facilitated dissection by partially dissolving internal organs of the beetle while causing little degradation of the cysticercoids. Harsh rehydration (5–10% KOH for 1 day followed by 5 days in water) not only dissolved internal beetle tissues but also severely damaged cysticercoids, such that parasite counts were unreliable. The degree of initial carcass desiccation had little effect on results following rehydration. However, regardless of treatment used, intact cercomers were rarely retained on rehydrated cysticercoids. Rehydration was less successful on early developmental stages of the parasite, which were recovered reliably only as they neared the cysticercoid stage. This method has utility for studies of parasite-induced mortality by permitting accurate and reliable parasite counts from dead, desiccated hosts.

Three species of genus Bychowskyella Akhmerov (1952), i.e. B. fossilisi Majumdar & Agarwal, 1989, B. tchangi Gusev, 1976 and B. wallagonia (Jain, 1959a) Gusev, 1961, were found to parasitize the gill filaments of siluriform fish in India. This redescription based on light microscopic examination of B. fossilisi, B. tchangi and B. wallagonia provides detailed taxonomic data for these species. We also amplified the 18S ribosomal RNA gene to evaluate the phylogenetic relationships of these three species. The morphological and genetic profiles confirmed the validation and taxonomical relationships of the above-mentioned species belonging to the genus Bychowskyella.

Adult Lecithaster mugilis Yamaguti, 1970 were found in Moolgarda seheli, Valamugil engeli and Liza subviridis in the coastal waters of Cat Ba Island (Halong Bay, Vietnam). Specimens of Lecithaster sudzuhensis n. sp. were found in Mugil cephalus located in an estuary of the Kievka River in the Primorsky region of Russia. Studies have demonstrated that these species share significant morphometric similarities with each other and with specimens of L. helodes Overstreet, 1973 isolated from M. cephalus and Mugil curema from the Mississippi Sound and adjacent waters. These three species differ from one another in the size of the pharynx and ventral sucker and in the ratio of suckers, while they differ from other species in the genus by having a relatively elongated oesophagus. Molecular analysis, using the 18S rRNA and 28S rRNA genes, confirmed the validity of L. mugilis and L. sudzuhensis n. sp. and demonstrated that these species form a shared cluster with L. gibbosus (Rud, 1802).

Two partial regions of ribosomal DNA (28S and 18S) were used to evaluate genetic variations among the species of Cornudiscoides, viz. C. proximus, C. geminus and C. agarwali, all parasites of Mystus vittatus (Bagridae) from River Gomati, Ganges River basin, India. Our findings demonstrated that both the large and small ribosomal subunits are useful for species identification and genetic characterization of parasites, leading to resolution of inter/intra-relationships at generic and specific levels. The secondary structures of all three species for 28S and 18S rRNA genes contained exact pattern matches (EMPs) displaying the high degree of similarity among them. The phylogenetic analyses within the members of Dactylogyridae demonstrated that species of Cornudiscoides cluster together for 28S rRNA and 18S rRNA genes.

Neotropical lizards are known to harbour rich nematode parasite faunas; however, knowledge of the diversity and patterns of infection are still lacking for many species. This is true for the genus Tropidurus, in which data on patterns of parasitism are known for only approximately 11 of its 30 species. We show that the nematode fauna associated with a population of Tropidurus montanus is composed of three species of host-generalist parasites with high overall prevalence. Male and female lizards did not differ in infection pattern and there was no relationship between host body size and intensity of infection for the most prevalent parasite species. Nevertheless, overall prevalence changed seasonally, with a higher proportion of parasitized individuals being found in the dry period than in the rainy period. We discuss our findings in the context of diet patterns of T. montanus, which we suggest may explain the similarities in prevalence and intensity of infection between the sexes. In addition, seasonal changes in diet are considered to be related to the observed differences in prevalence between dry and rainy periods.

We examined the associations between intestinal helminth infracommunity structure and infection parameters and the age, size, and year and region of collection of 130 female lesser scaup (Aythya affinis) during their 2014–2015 spring migrations through the upper Midwest, USA. We identified a total of 647,174 individual helminths from 40 taxa, including 20 trematodes, 14 cestodes, 4 nematodes and 2 acanthocephalans parasitizing lesser scaup within the study area. Lesser scaup were each infected with 2–23 helminth taxa. One digenean, Plenosoma minimum, is reported for the first time in lesser scaup and in the Midwest. Mean trematode abundance and total helminth abundance was significantly less in 2015 than 2014, and we suspect that colder weather late in 2015 impacted the intermediate host fauna and caused the observed differences. Brillouin's species diversity of helminths was greatest in the northernmost region of the study area, which coincides with the range of a non-indigenous snail that indirectly causes annual mortality events of lesser scaup. While host age and size were not determined to be influential factors of helminth infracommunity structure, non-parametric ordination and permutational analysis of co-variance revealed that year and region of collection explained differences in helminth infracommunities. Our results suggest that spatiotemporal variations play an important role in the structure of intestinal helminth infracommunities found in migrating lesser scaup hosts, and may therefore impact host ability to build endogenous reserves at certain stopover locations in the Midwest.

One new species from Qinghai Province, China, Labronemella major n. sp., is described. The new species is characterized by a body length of 3.03–3.34 mm; lip region wide, offset by a distinct depression, disc-like with six separated inner liplets; amphid fovea funnel-shaped, distinctly bulged on body surface in scanning electron micrographs; odontostyle long (35–39 μm) with distinct lumen, aperture about 39–47% of its length; odontophore rod-like and long; guiding ring double; pharyngeal basal expansion about half of the total neck length; uterus relatively long and tripartite; vulva transverse and sclerotized; spicules 81–90 μm long; ventromedial supplements 19–23; tail short, rounded to conoid. It can be differentiated from all other species of the genus by its relatively longer body, odontostyle and spicules, and wider lip region. Due to the lip region being offset by a deep constriction, and the long (three or more times the body diameter at mid-body) tripartite uterus, the new species is close to Labronemella czernowitzensis (Micoletzky, 1922) Andrássy, 2002 and Labronemella labiata Andrássy, 1985. An improved key to the genus including the new species is provided.

The fish host (Wallago attu) and monogenoid parasite (Thaparocleidus sp.) have been recorded during 2 years (2011 and 2012) to investigate intra/interspecific interactions among query species (T. sudhakari (Gusev, 1976) Lim, 1996; T. indicus (Kulkarni, 1969) Lim, 1996; T. gomtius (Jain, 1952) Lim, 1996; T. yogendraii Agrawal, 1981 and T. wallagonius Jain, 1952) in the light of parasitic worm burden, morphological and molecular data. Each species is highly host specific (oioxenous), with a specialized functional niche. Being niche specialists, they exhibit niche overlapping along with co-existence due to reproductive barrier. Furthermore, a molecular marker, affirming clear-cut genetic variation in spite of structural entities, provides evidence for infra-speciation as well as co-speciation.

Among eyeflukes, Tylodelphys Diesing, 1850 includes diverse species able to infect the eyes, but also the brain, pericardial sac and body cavity of their second intermediate host. While the genus shows a cosmopolitan distribution with 29 nominal species in Africa, Asia, Europe and America, a likely lower research effort has produced two records only for all of Australasia. This study provides the first description of a species of Tylodelphys and the first record for a member of the Diplostomidae in New Zealand. Tylodephys sp. metacercaria from the eyes of Gobiomorphus cotidianus McDowall, 1975 is distinguished from its congeners as being larger in all, or nearly all, metrics than Tylodelphys clavata (von Nordmann, 1832), T. conifera (Mehlis, 1846) and T. scheuringi (Hughes, 1929); whereas T. podicipina Kozicka & Niewiadomska, 1960 is larger in body size, ventral sucker and holdfast sizes and T. ophthalmi (Pandey, 1970) has comparatively a very small pharynx and body spination. Tylodelphys sp. exhibits consistent genetic variation for the 28S rDNA, internal transcribed spacer (ITS) and Cox1 genes, and phylogenetic analyses confirm that it represents an independent lineage, closely related to North American species. Morphological and molecular results together support the distinct species status of Tylodephys sp. metacercaria, the formal description and naming of which await discovery of the adult. Furthermore, the validity of T. strigicola Odening, 1962 is restored, T. cerebralis Chakrabarti, 1968 is proposed as major synonym of T. ophthalmi, and species described solely on the basis of metacercariae are considered incertae sedis, except those for which molecular data already exist.

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.

Seizures, headache, depression and neurological deficits are the signs and symptoms most frequently reported in human neurocysticercosis. However, the cause of the associated learning and memory deficits is unknown. Here, we used Taenia crassiceps infection in mice as a model of human cysticercosis. The effects of T. crassiceps metacestode infection or T. crassiceps metacestode factor (MF) treatment on mouse hippocampal cells were studied; control mice were included. At 45 days after infection or treatment of the mice with MF, all mice were anaesthetized and perfused transcardially with saline followed by phosphate-buffered 10% formalin. Then the brains were carefully removed. Coronal sections stained using several techniques were analysed. Extensive and significant apoptosis was found in the experimental animals, mainly in the dentate gyrus, CA1, CA2, CA3 and neighbouring regions, in comparison with the apparently intact cells from control mice (P < 0.01). These results suggest that neurological deficits, especially the learning and memory deficits, may be generated by extensive apoptosis of hippocampal cells.

The prevalence of canine Dirofilaria infection in Maio Island (Cape Verde) was analysed by serology, morphological and molecular identification of the parasite species. Blood and sera were collected from 150 dogs and 80 cats aged over 6 months from various localities of the island. DNA was extracted from blood and samples were screened by polymerase chain reaction (PCR) using microfilaria-specific primers. No Dirofilaria immitis was found in dogs while D. repens microfilariae were found in 5.3% of dogs and 6% were positive by PCR. The species identity was confirmed by sequencing of PCR products, which showed almost 100% homology with D. repens European sequences published in GenBank. No difference in Dirofilaria infection was observed between males and females or in dogs with different weights. However, older dogs and those from the western part of Maio Island were more frequently infected. No Dirofilaria was found in cats. This study represents the first evidence of D. repens in Cape Verde (West Africa) and highlights the need for implementing control measures and for a better surveillance of dirofilariosis in Africa.

Haemonchus contortus is a major parasite of small ruminants and its blood-feeding behaviour causes effects ranging from mild anaemia to death. Knowledge of the genetic variation within and among H. contortus populations can provide the foundation for understanding transmission patterns and aid in the control of haemonchosis. Adult male H. contortus were collected from three geographical regions in Egypt. The second internal transcribed spacer (ITS2) of nuclear ribosomal DNA was amplified using the polymerase chain reaction (PCR) and sequenced directly. The population genetic diversity and sequence variations were determined. Nucleotide sequence analyses revealed one genotype (ITS2) in all worms, without genetic differentiation. The similarity in population genetic diversity and genetic patterns observed among the three geographical regions could be attributed to possible movement between the sites. This is the first study of genetic variation in H. contortus in Egypt. The present results could have implications for the rapid characterization of H. contortus and other trichostrongyloid nematodes, and evaluation of the epidemiology of H. contortus in Egypt.

Extensive field surveys of rodents were conducted in Cambodia from 2008 to 2014 to study the diversity and ecology of helminth infection in wild rodent populations. Gastrointestinal helminths were isolated from 14 species of rodents (569 individuals) trapped from different habitats (forest, dry land, rain-fed land and human settlements) in four provinces of Cambodia (Krong Preah Sihanouk, Mondolkiri, Pursat and Steung Treng). The average prevalence of parasitic infection was 58.5% (range, 16.0–64.7%), and 19 helminth taxa were identified in total. Trichostrongylid nematodes were the most prevalent (25.8%), followed by Raillietina sp. (14.1%), Gongylonema neoplasticum (10.7%), Syphacia muris (9.8%) and Hymenolepis diminuta (9.6%). Potential rodent-borne zoonotic helminths were also identified, and the risks of helminthiasis were discussed. The status of helminth infection and species diversity in rodents from settlements were significantly lower than in rodents from forest and peri-domesticated habitats, which indicates that habitat alteration might affect helminth infection and diversity in rodent hosts. Generalized linear models revealed that host attributes (host species and maturity) and environmental factors (habitat and geographical location) were explanatory variables for helminth infection in these rodents. Using network analyses, we showed that the oriental house rat, Rattus tanezumi, was the most central host in the rodent–helminth assemblage, based on the number of helminth taxa it shared with other rodent species. Therefore, R. tanezumi could play an important role in rodent–helminth interactions and helminth transmission to other rodent hosts.

Adults of Lasiotocus lizae Liu, 2002 (Monorchiidae) were found in the mullet Liza longimanus (Günther) from Tonkin Bay, near Cat Ba Island, Vietnam. In this region, flukes belonging to the genus Paucivitellosus (Bivesiculudae) were found in Liza subviridis (Valenciennes), Liza engeli (Bleeker) and Valamugil seheli (Forskåi). Results of investigations showed that morphological features of L. lizae (like L. glebulentus Overstreet, 1971) do not meet the criteria of the genus Lasiotocus. In addition, L. lizae is highly differentiated from other species of Lasiotocus from which molecular data were obtained, including L. arrhichostoma Searle, Cutmore et Cribb, 2014 and L. typicum (Nicoll, 1912). Phylogenetic analyses revealed that L. lizae differs considerably from other species of the genus Lasiotocus presented in the GenBank database. We have identified a new species of the genus Paucivitellosus–P. vietnamensis sp. n. – from L. subviridis, which differs from P. fragilis Coil, Reid et Kuntz, 1965 by metrical and molecular (18S rRNA) data, and from P. hanumanthai Mani, 1989 by metric features. Our results also show considerable molecular differentiation between P. vietnamensis sp. n. and Paucivitellosus spp. recovered from L. engeli and V. seheli in Vietnam.