Waddycephalus is an understudied genus of pentastomids native to Australia and south-east Asia. The genus was recognized in 1922 but there has been little research on these pentastomid tongue worms over the last century. A few observations suggest a complex life cycle through 3 trophic levels. We aimed to add knowledge to the Waddycephalus life cycle in woodland habitats in the Townsville region of north-east Australia. We used camera trapping to identify the most likely first-intermediate hosts (coprophagous insects), we conducted gecko surveys to identify multiple new gecko intermediate host species and we dissected road-killed snakes to identify additional definitive hosts. Our study paves the way for further research into the intriguing life cycle of Waddycephalus, investigation of spatial variation in prevalence and impacts of the parasite on host species.

Rodents living in a subterranean ecotope face a unique combination of evolutionary and ecological pressures and while host species evolution may be driven by the selective pressure from the parasites they harbour, the parasites may be responding to the selective pressures of the host. Here, we obtained all available subterranean rodent host–parasite records from the literature and integrated these data by utilizing a bipartite network analysis to determine multiple critical parameters to quantify and measure the structure and interactions of the organisms present in host–parasite communities. A total of 163 species of subterranean rodent hosts, 174 parasite species and 282 interactions were used to create 4 networks with data well-represented from all habitable continents. The results show that there was no single species of parasite that infects subterranean rodents throughout all zoogeographical regions. Nevertheless, species representing the genera Eimeria and Trichuris were common across all communities of subterranean rodents studied. Based on our analysis of host–parasite interactions across all communities studied, the parasite linkages show that community connectance (due to climate change or other anthropogenic factors) appears to show degraded linkages in both the Nearctic and Ethiopian regions: in this case parasites are acting as bell-weather probes signalling the loss of biodiversity.

A new species of Ancyracanthus, parasite of the electric eel Electrophorus varii, in the Brazilian Amazon, is described based on morphological and molecular characterization. Ancyracanthus electrophori n. sp. differs from the two congeners namely, Ancyracanthus pinnatifidus and Ancyracanthus schubarti, based on the structure of cephalic appendages, number and arrangement of caudal papillae in males, vulva very close to anus in females, eggs with smoothly mamillated shell, host taxon and geographical origin. Moreover, the new species is the first in the genus to be described with thorny cuticular rings and to be observed with the use of scanning electron microscopy (SEM). The morphology of A. pinnatifidus and A. schubarti is still poorly-known and should be revised in details; however, the separation between them and the new species was clear. Genetic characterization based on 28S rDNA and cytochrome c oxidase subunit I (cox1) mtDNA partial sequences, performed for the first time in Acyracanthus, along with phylogenetic reconstructions using both genetic markers, placed Ancyracanthus electrophori n. sp. in a suggestive basal position within Gnathostomatidae. Phylogenetic reconstructions using cox1 sequences also suggested lack of monophyly in the genera Gnathostoma and Spiroxys and, consequently, in the subfamilies Gnathostominae and Spiroxyinae. However, such results are preliminary. With the first genetic characterization and observations using SEM in Ancyracanthus, resulting in the discovery of a new species and in the expansion of the geographical occurrence of the genus to Amazonian fish, an important step towards a better understanding of these nematodes has been taken.

We report the first mermithid nematode found to be parasitic in a marine tanaidacean crustacean. Ten host tanaidaceans were collected from a depth of 52 m in Otsuchi Bay, Iwate, Japan, north-western Pacific, and identified as a species in the tanaidid genus Zeuxo Templeton, 1840. Nematodes occurred in the host's body cavity; in one case, at least two individuals inhabited a single host. We provide a brief description and illustrations of the morphology of the nematode. In a phylogenetic reconstruction based on the 18S ribosomal RNA gene, the nematode nested in a clade otherwise containing mermithids from terrestrial or freshwater hosts, showing an expansion in host utilization in Mermithidae Braun, 1883 from terrestrial/freshwater hosts to a marine organism.

We conducted a paleoparasitological study on sediment samples from two trash pits and a cesspool, collected during an archaeological assessment of a building located in the historic downtown of the city of Córdoba, Argentina. People have used these premises for residential and commercial purposes since the beginning of the seventeenth century, although the samples analyzed correspond to nineteenth-century contexts. Light microscopy examination revealed the presence of parasite eggs of whipworm (Trichuris sp.), possibly roundworm (Ascaris lumbricoides), and tapeworm (taeniid). The presence of these fecal-oral and food-borne transmitted helminths supports other lines of evidence that indicate poor sanitation and hygiene habits and inadequate food processing, which may have contributed to the high incidence and mortality of gastrointestinal diseases recorded at that time. The paleoparasitological data agree with the historical information on the health status of the populations that inhabited the city of Córdoba in the past, especially in relation to their habits and diet.

While much attention has been paid to vector-borne filariasis, diseases that threaten millions of people in tropical and subtropical countries, the literature on host–parasite associations and transmission strategies of filarial nematodes in wildlife is scarce. Here, we report the co-occurrence of chigger mites (Eutrombicula alfreddugesi) and onchocercid nematodes (Oswaldofilaria chabaudi) parasitizing the lizard Tropidurus torquatus in the State of Minas Gerais, Brazil. Examination of chiggers established, for the first time, the occurrence of microfilariae in trombiculid mites (Trombiculidae). These larvae were morphologically similar to those recovered from adult females of O. chabaudi. The current evidence suggests that chiggers do not play a role in the transmission of filarioid nematodes, but rather act as accidental or dead-end hosts. Nevertheless, considering the polyphagous nature of trombiculid mites, similar to blood-sucking insects involved in the transmission of several infectious diseases, further studies may shed light on the potential role of chiggers as vectors of filarioids.

Integrative taxonomy was used to evaluate two component populations of Procamallanus (Spirocamallanus) inopinatus in Brazil and the phylogeny Camallanidae. Parasite populations were collected in the characiform Anostomoides passionis from River Xingu (Amazon basin) and Megaleporinus elongatus from River Miranda (Paraguay basin). Morphology was analysed using light and scanning electron microscopy (SEM). Genetic characterization was based on partial sequences of the 18S and 28S rDNA, and COI mtDNA. Phylogenies were based on 18S and COI due to data availability. Generalized Mixed Yule Coalescent (GMYC), Poisson Tree Process (PTP) and *BEAST were used for species delimitation and validation. SEM revealed for the first time the presence of minute denticles and pore-like structures surrounding the oral opening, phasmids in females and confirmed other important morphological aspects. Statistical comparison between the two-component populations indicated morphometric variations, especially among males. The different component population of P. (S.) inopinatus showed variable morphometry, but uniform morphology and were validated as conspecific by the GMYC, PTP and *BEAST. Some camallanid sequences in GenBank have incorrect taxonomic labelling. Host, environment and geographic aspects seem to be related to some lineages within Camallanidae; however, their real phylogenetic meanings are still unclear.

Nymphonella tapetis (Pycnogonida, Ascorhynchidae) is an endoparasitic sea spider affecting bivalves. Recently, sea spiders have been found on a massive scale in the commercially important Manila clams (Veneridae, Ruditapes philippinarum) in Japan (Tokyo Bay). Simultaneously, mass mortality has occurred in this area. Local fishers assumed that this mass mortality was caused by the parasitic sea spider, despite the effect of the parasite and parasite intensity on the host being unknown. To evaluate the susceptibility of the Manila clam to sea spider infestation and the impact on mortality levels, we established six treatments at different infection intensities (density of newly hatched larvae of sea spiders) over a 6-month long laboratory experiment. We monitored mortality and three susceptibility indices (clearance rate, sand-burrowing speed and adductor muscle strength) under sufficient food conditions. Parasitization by sea spider affected clearance rate and sand-burrowing speed. The pattern of parasitic intensity effects on survival of Manila clam hosts was shown to be dependent on the levels of parasite numbers, i.e. clams with lower parasitic levels (total of <200 hatching larvae of sea spider given to a host) have a higher survival rate, and high mortality of host clams was shown in excessively higher parasitic densities (400–4000 individuals). Such pattern of parasitic effects on host survival might be one of the causes of mass mortality of Manila clams occurring in the field.

The new genus Celatogloea is proposed to accommodate a monosterigmate, heterobasidiomycetous, intrahymenial parasite of Corticium roseum, previously not distinguished from its host. The new combination Celatogloea simplicibasidium is proposed, based on Laeticorticium simplicibasidium.

The whipworm, Trichuris trichiura L., is one of the most common human intestinal parasites worldwide, yet little is known of its origin and global spread. Archaeological records for this nematode have all been of Neolithic or later date, suggesting a possible association between the spread of pastoral farming and human acquisition of whipworm. This paper reports the discovery of eggs of the genus Trichuris in late Mesolithic deposits from south Wales, indicating that whipworm was present in Europe before the arrival of agriculture. This raises the possibility that human infection by Trichuris arose through contact with wild animals in parts of the landscape frequented by both human and animal groups.

Free-living nematodes, commonly known as eelworms, eat bacteria in the soil and may succumb to infection by delicate endoparasitic fungi. In the wild these fungi are host-dependent and infect nematodes with small unicellular spores that either lodge inside the nematode following ingestion, or adhere to the nematode cuticle. Some endoparasites, such as Drechmeria coniospora and Harposporium leptospira, are readily isolated, ubiquitous species, infecting common soil nematodes in a variety of substrates. Others, like the elusive Plesiospora globosa, are seldom seen because they are host-specific for rarer species of nematode occurring in specific habitats.