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During an ichthyoparasitological survey in 2017-2019, six species of acanthocephalans were found among Taiwan's freshwater (Cypriniformes: Xenocyprididae, Cyprinidae) and marine fishes (Scombriformes: Scombridae, Trichiuridae; Anabantiformes: Channidae; Carangaria/misc: Latidae): Micracanthorhynchina dakusuiensis (Harada, 1938), Rhadinorhynchus laterospinosus Amin, Heckmann et Ha, 2011, Pallisentis rexus Wongkham et Whitfield, 1999, Longicollum sp., Bolbosoma vasculosum (Rudolphi, 1819), and one new species, Micracanthorynchina brevelemniscus sp. n. All species are morphologically characterised and illustrated using light and scanning electron microscopy. The finding of R. laterospinosus, P. rexus and B. vasculosum is the first record for these species in Taiwan. Micracanthorhynchina brevelemniscus is similar to Micracanthorhynchina motomurai (Harada, 1935) and M. dakusuiensis in proboscis armature but differs from M. motomurai by larger eggs (53-59 × 15-16 µm vs 40 × 16 µm) and by the number of cement glands (6 vs 4) and from M. dakusuiensis by shorter body length (2.2-2.9 mm vs 4.0 mm in males and 2.9-4.1 mm vs 7.6 mm in females), by the location of the organs of the male reproductive system (from level of the posterior third of the proboscis receptacle in M. brevelemniscus vs in the posterior half of the trunk in M. dakusuiensis), and by length of lemnisci (lemnisci shorter than the proboscis receptacle vs lemnisci longer than the proboscis receptacle). Phylogenetic analyses of almost complete 18S rRNA gene revealed paraphyly of the family Rhadinorhynchidae suggested in previous studies. Micracanthorhynchina dakusuiensis and M. brevelemniscus formed a strongly supported cluster, which formed the earliest diverging branch to the rest of the rhadinorhynchids and transvenids.

Recent examinations of marine perciform fishes from off the Florida coast in the Gulf of Mexico and Straits of Florida, USA, revealed the presence of the following six species of Philometra Costa, 1845 (Nematoda: Philometridae): P. haemulontis sp. n. (males and females) from the ovary of Haemulon plumierii (Lacepède) (type host) and H. aurolineatum Cuvier (both Haemulidae); Philometra synagridis Moravec, Bakenhaster et Fajer-Ávila, 2014 (males and females) from the ovary and testes of Lutjanus synagris (Linnaeus) (Lutjanidae); P. margolisi Moravec, Vidal-Martínez et Aguirre-Macedo, 1995 (male) from the ovary of Hyporthodus nigritus (Holbrook) (Serranidae) (new host record; probably a paradefinitive host); P. andersoni sp. n. (male) from the ovary of H. nigritus; Philometra sp. 1 (male) from the ovary of Rhomboplites aurorubens (Cuvier) (Lutjanidae); and Philometra sp. 2 (females) from the subcutaneous tissue of the anterior-most head sinuses of Hyporthodus niveatus (Valenciennes) (Serranidae). Specimens of species are described and illustrated based on light and (except for Philometra sp. 1) scanning electron microscopical examinations. Philometra haemulontis sp. n. differs from all congeners in the unique structure of the gubernaculum, whereas P. andersoni sp. n. can be differentiated from other gonad-infecting congeners parasitising the Serranidae by a combination of morphological features. Females of P. synagridis are described for the first time. Gravid females of Philometra sp. 2 are similar to those of P. morii Moravec, Bakenhaster et Fajer-Ávila, 2010, a subcutaneous parasite of Epinephelus morio (Valenciennes) (Serranidae) in the Gulf of Mexico.

Two species of Spinitectus Fourment, 1884 have been recorded from southern Africa, namely Spinitectus polli Campana-Rouget, 1961 and Spinitectus petterae Boomker, 1993, both from the Limpopo River system. Spinitectus petterae was described from North African catfish, Clarias gariepinus (Burchell), whereas S. polli infects squeakers, Synodontis spp. During parasitological surveys in the Vaal River system (Orange River catchment), Spinitectus specimens were collected from C. gariepinus. These systems are adjacent but not connected. Therefore, this study aimed to identify the specimens collected using morphological and molecular techniques. The morphological study included light and scanning electron microscopy of whole specimens and excised spicules. Specimens were genetically characterised using 18S rDNA, 28S rDNA and cox1 mtDNA. Additionally, immature specimens of S. petterae were collected near the type locality. Morphological characteristics were most similar to S. petterae from C. gariepinus, whereas genetic data were dissimilar to all available data for the genus. Additional morphological characteristics noted for S. petterae in the present study were the details of the left and right spicule structure and the porous structures on the pseudolabia. Specimens from the Vaal River system differed from those originally described as S. petterae by additional spines posterior to the third ring, lacking caudal alae and variable total body and male oesophagus length. Based on 18S rDNA, haplotypes from the type locality varied only slightly from the study material, supporting the morphological identification. However, 28S rDNA and, more conspicuously, cox1 mtDNA displayed substantial variation between specimens from these localities, which needs further investigation. Haplotypes generated in the present study were highly dissimilar to those characterised for S. petterae from Tanzania and Egypt. Nevertheless, the nematodes collected from C. gariepinus in the Vaal River system are considered S. petterae. This study expands the geographical distribution and adds additional morphological and genetic information for S. petterae, contributing to the limited knowledge of African species of Spinitectus.

Susceptibility to COVID-19, the most devastating global pandemic, appears to vary widely across different population groups. Exposure to toxoplasmosis has been proposed as a theory to explain the diversity of these populations. The aim of the present study was to investigate the possible association between latent toxoplasmosis and COVID-19 and its probable correlation with markers of oxidative stress, C-reactive protein (CRP) and ferritin. In a case-control study, blood samples were collected from 91 confirmed (48 non-pneumonic; NP, and 43 pneumonic; P) COVID-19 patients and 45 healthy controls. All participants were tested for IgG anti-Toxoplasma gondii antibodies and oxidative stress markers (nitric oxide [NO], superoxide dismutase [SOD] and reduced glutathione [GSH]), and CRP and serum ferritin levels were determined. In COVID-19 patients, IgG anti-T. gondii antibodies were found in 54% compared to 7% in the control group, with the difference being statistically significant (P ˂ 0.001). However, no significant correlation was found between the severity of COVID-19 and latent T. gondii infection. Latent toxoplasmosis had a strong influence on the risk of COVID-19. NO and SOD levels were significantly increased in COVID-19 patients, while GSH levels decreased significantly in them compared to control subjects (P ˂ 0.001 for both values). CRP and ferritin levels were also significantly elevated in P COVID-19 patients infected with toxoplasmosis. This is the first study to look at the importance of oxidative stress indicators in co-infection between COVID-19 and T. gondii. The high prevalence of latent toxoplasmosis in COVID-19 suggests that T. gondii infection can be considered a strong indicator of the high risk of COVID-19.

Plastination is a preservation method for biological specimens, with important advantages over classic conservation techniques with formaldehyde or alcohol. Plastinated specimens are dry, odourless, and free of carcinogenic and toxic solutions. There are only few references about the plastination of parasites. Moreover, there is no information on the effect of plastination on the morphology and morphometry of these animals. The aim of this study was to define a plastination protocol to preserve various species of parasites, namely the nematodes Parascaris equorum (Goeze, 1782); Ascaris suum Goeze, 1782 and Dirofilaria immitis (Leidy, 1856); the acanthecephalan Macracanthorhynchus hirudinaceus (Pallas, 1781); the trematodes Fasciola hepatica Linnaeus, 1758 and Dicrocoelium dendriticum (Rudolphi, 1819) and the tapeworm Taenia sp. in the best morphological and morphometric conditions. Results showed that some individuals suffered collapse (P. equorum, A. suum, and D. dendriticum). However, other parasites presented good results with almost no change after plastination (D. immitis, M. hirudinaceus and F. hepatica). In conclusion, conventional plastination allowed anatomical preservation of all helminths tested, but modifications to the protocol are needed to prevent collapse.

Current data on reproductive biology and population dynamics of the acanthocephalans are scarce mainly in regions from the tropical Pacific. An analysis was done to identify possible factors that influence variation in infection levels of the acanthocephalan Pseudoleptorhynchoides lamothei Salgado-Maldonado, 1976 in its final host, the blue sea catfish Ariopsis guatemalensis (Günther, 1864), and describe its main reproductive traits. A total of 1,094 A. guatemalensis were collected from Tres Palos Lagoon from August 2014 to December 2015. Prevalence of P. lamothei varied from 1.47% to 38.33%, and mean abundance from 0.03 to 4.44 helminths per examined host. In female P. lamothei relative fecundity increased with total length. Temporal variations in P. lamothei infection levels were attributed mainly to changes in host feeding and reproductive behaviour in response to local environmental factors as climatic season, and variations in water temperature.

Proliferative kidney disease (PKD) is a widespread temperature-dependent disease in salmonids caused by the myxozoan parasite, Tetracapsuloides bryosalmonae (Canning, Curry, Feist, Longshaw et Okamura, 1999) (Tb). Tb has a two-host life cycle, involving fish as an intermediate host and freshwater bryozoans as the definitive host. Although salmonids are acknowledged as hosts for the parasite, it is less clear which fish species are active hosts in the life cycle of Tb. Differences in infection dynamics have been observed between some fish species, which are thought to be related to the existence of two main Tb-strains, the American and European. Iceland, having three species of indigenous salmonids and positioned geographically between Europe and North America, is an ideal location to study the natural development of Tb in wild fish. The main aim of this study was to determine the genetic origin of Tb in Iceland and confirm whether mature spores are produced in Icelandic salmonids. In this study, Icelandic salmonids were infected with the European Tb-strain. In situ hybridisation revealed that intraluminal sporogonic stages, including mature spores, were commonly observed in all three salmonid species. The presence of intraluminal stages has previously been confirmed in brown trout Salmo trutta Linnaeus and Atlantic salmon S. salar Linnaeus in Europe, but they have only been observed in Arctic charr Salvelinus alpinus (Linnaeus) in North America, infected by the local strain. This is, therefore, the first time that sporogonic stages have been observed in Arctic charr in Europe, where fish are infected with the European Tb-strain. Our data strongly suggest that all the three salmonid species inhabiting Icelandic waters serve as active hosts in the life cycle of Tb. However, for full confirmation, transmission trials are needed.

Based on light and electron microscopical studies, a new nematode parasite, Echinocephalus inserratus sp. n. (Spirurida: Gnathostomatidae), is described from the spiral valve of the broad cowtail stingray Pastinachus ater (Macleay) (Dasyatidae, Myliobatiformes) from off New Caledonia. The new species is morphologically and biometrically most similar to Echinocephalus overstreeti Deardorff et Ko, 1983, differing from it mainly in the absence of serrations on the posterior parts of pseudolabia and on interlabia, and in having a longer gubernaculum (150-299 µm long). Morphologically unidentifiable, mostly encapsulated larvae of Echinocephalus spp. were recorded from the following six species of teleost fishes collected in New Caledonian waters, serving as paratenic hosts: Perciformes: Acanthopagrus berda (Forsskål) (Sparidae) and Nemipterus furcosus (Valenciennes) (Nemipteridae); Tetraodontiformes: Abalistes stellatus (Anonymous), Pseudobalistes fuscus (Bloch et Schneider) (both Balistidae), Lagocephalus sceleratus (Gmelin) (Tetraodontidae) and Aluterus monoceros (Linnaeus) (Monacanthidae). Co-parasitising larvae of Ascarophis sp. and Hysterothylacium sp. were also collected from P. fuscus. All these findings represent new host and geographical records. A key to valid species of Echinocephalus Molin, 1858 is provided.

An outbreak of trichinellosis occurred in Stari Banovci, a settlement in the municipality of Stara Pazova, Srem, Republic of Serbia, in March-April 2019. A total of 28 persons were exposed and trichinellosis was confirmed in 24 of them. This outbreak involved members of eight families, their relatives and friends. The infection, due to Trichinella spiralis (Owen, 1835), was associated with consumption of pork sausages procured in a local butcher's shop. The trace-back study revealed that the meat originated from swine that was raised on a small farm belonging to the owner of the shop, who did not have permission from the Veterinary Directorate for slaughtering animals and who put on the market sausages prepared from uninspected meat. Trichinellosis was accompanied by typical clinical symptoms. However, the unusual occurrence of high percentage of pulmonary complications was noticed. The description of this outbreak indicates that medical practitioners should initiate treatment immediately in cases of high suspicion of trichinellosis, even if the serology is negative, to prevent the complications of the disease. In spite of significant achievements in the control of Trichinella infection among domestic pigs and humans in the last 10 years, it is obvious that such cases of breeding animals under inappropriate conditions, slaughtering them without approval and placing uninspected pork on the market represent a source of sporadic outbreaks in Serbia.

A total of 52 specimens of the Pacific seabream Acanthopagrus pacificus Iwatsuki, Kume et Yoshino from the Gulf of Tonkin off Vietnam were examined for monogeneans. Twenty fish were parasitised by 101 individuals of five monogenean species, including two known species Allodiscocotyla diacanthi Unnithan, 1962 and Heterapta chorinemi (Tripathi, 1956), as well as three new species, Polylabroides tienyenensis sp. n., Polylabroides tonkinensis sp. n. and Metacamopia lebedevi sp. n. Polylabroides tienyenensis and P. tonkinensis are morphologically more similar to Polylabroides guangdongensis Zhang et Yang, 2001 in comparison with other species within the genus, based on the absence of small spines on the cirrus. However, P. tonkinensis is distinguished from P. guangdongensis by fewer clamps on the haptor and by the different shapes of the large spines on the cirrus. Similarly, P. tienyenensis differs from P. guangdongensis by vaginal ducts with fewer branches, fewer clamps and smaller egg size. Metacamopia lebedevi is distinguished from Metacamopia chorinemi (Yamaguti, 1953) by the arrangement of testes (one row vs two rows), diverticula absent in the oesophagus, and the number of anchor pairs (one vs two); it differs from Metacamopia oligoplites Takemoto, Amato et Luque, 1996 by the smaller haptor, shape and absence of small sclerotised hooks, the number of ribs in their clamps, and the position of the testes; it can be separated from Metacamopia indica (Unnithan, 1962) by having fewer testes and lacking sclerotised structures in the vagina. The present study also provides the measurements for A. diacanthi, H. chorinemi, and proposes a new key to all species of Polylabroides.

Abstract: The emergence of cryptosporidiosis, a zoonotic disease of the gastrointestinal and respiratory tract caused by Cryptosporidium Tyzzer, 1907, triggered numerous screening studies of various compounds for potential anti-cryptosporidial activity, the majority of which proved ineffective. Extracts of Indonesian plants, Piper betle and Diospyros sumatrana, were tested for potential anti-cryptosporidial activity using Mastomys coucha (Smith), experimentally inoculated with Cryptosporidium proliferans Kváč, Havrdová, Hlásková, Daňková, Kanděra, Ježková, Vítovec, Sak, Ortega, Xiao, Modrý, Chelladurai, Prantlová et McEvoy, 2016. None of the plant extracts tested showed significant activity against cryptosporidia; however, the results indicate that the following issues should be addressed in similar experimental studies. The monitoring of oocyst shedding during the entire experimental trial, supplemented with histological examination of affected gastric tissue at the time of treatment termination, revealed that similar studies are generally unreliable if evaluations of drug efficacy are based exclusively on oocyst shedding. Moreover, the reduction of oocyst shedding did not guarantee the eradication of cryptosporidia in treated individuals. For treatment trials performed on experimentally inoculated laboratory rodents, only animals in the advanced phase of cryptosporidiosis should be used for the correct interpretation of pathological alterations observed in affected tissue. All the solvents used (methanol, methanol-tetrahydrofuran and dimethylsulfoxid) were shown to be suitable for these studies, i.e. they did not exhibit negative effects on the subjects. The halofuginone lactate, routinely administered in intestinal cryptosporidiosis in calves, was shown to be ineffective against gastric cryptosporidiosis in mice caused by C. proliferans. In contrast, the control application of extract Arabidopsis thaliana, from which we had expected a neutral effect, turned out to have some positive impact on affected gastric tissue.

Cats are important hosts for different zoonotic parasites that can be hazardous to human health. To date, few studies have attempted to identify the factors affecting parasitic infections in shelter animals. This study aims to analyse the presence of endoparasites in shelter cats in Tartu, Estonia, and identify factors affecting endoparasite prevalence and intensity. The risk factors considered were age, location (urban vs rural cats) and time spent in shelter. In total, 290 faecal samples were collected from cats at an animal shelter in 2015-2016 and investigated for endoparasites using the concentration flotation technique. In total, 138 shelter cats (47.6%) were infected with endoparasites and their overall prevalence was: Toxocara cati (36.6%), Cystoisospora spp. (12.4%), Taeniidae gen. sp. (4.1%), Toxoplasma gondii/Hammondia hammondi (3.4%), Eucoleus aerophilus (2.1%), Cryptosporidium spp. (2.1%), Ancylostoma sp. (0.7%) and Giardia sp. (0.7%). Coinfections occurred in 38 cats (13.1%) most frequently of T. cati and Cystoisospora spp. (4.5%), Cystoisospora spp. and T. gondii/H. hammondi (2.1%). Where species identification of cestode and nematode samples was not possible according to morphology, genetic analysis of the mitochondrial cox1 gene was carried out. DNA was successfully analysed for 6 out of 13 samples that required genetic identification, revealing Ancylostoma tubaeforme in one nematode sample and Hydatigera taeniaeformis in five cestode samples. Cats from rural areas had significantly higher endoparasite prevalence than cats from urban areas. Helminth prevalence decreased to some extent due to anthelmintic treatment in cats available for adoption (held ≥15 days in the shelter), whereas the prevalence of infection with protists increased significantly in these animals. It is important to note that the analysis revealed lower infection intensity for quarantine cats (held 1-14 days in the shelter) compared with cats available for adoption. The relatively high prevalence of endoparasites (including zoonotic) in shelter cats ready for adoption suggests that current anthelminthic procedures require improvements.

As presently defined, the tapeworm genus Andrya Railliet, 1895 (Cyclophyllidea: Anoplocephalidae sensu stricto) includes the type species A. rhopalocephala (Riehm, 1881) in hares of the genus Lepus Linnaeus (Leporidae) in western Eurasia and four species in cricetid (Neotominae, Sigmodontinae) and octodontid rodents in North and South America. The host range of Andrya is puzzling, because it is the only genus of anoplocephalid (s. s.) cestodes parasitising both rodents and lagomorphs. The present morphological analysis shows that the American species of Andrya share multiple consistent features, in which they differ from those of A. rhopalocephala and the morphologically related Neandrya cuniculi (Blanchard, 1891). The main differences concern the position of the uterus with respect to the longitudinal osmoregulatory canals and testes. Consequently, a new genus Andryoides gen. n. is proposed for the American species, resulting in the following combinations: Andryoides neotomae (Voge, 1946) comb. n. (type species), Andryoides octodonensis (Babero et Cattan, 1975) comb. n., Andryoides vesicula (Haverkost et Gardner, 2010) comb. n. and Andryoides boliviensis (Haverkost et Gardner, 2010) comb. n. However, A. boliviensis is regarded here as a junior synonym of A. vesicula (new synonymy). The present study also defines the morphological key features for all the valid genera of cestodes of the family Anoplocephalidae (s. s.), and discusses the phylogenetic affinities and historical biogeography of Andryoides and other endemic American anoplocephalid cestodes.

Trichodina centrostrigeata Basson, Van As et Paperna, 1983 from Oreochromis mossambicus (Peters) and O. niloticus (Linnaeus) from different host populations from Argentina, Mexico and South Africa was reviewed. Although T. centrostrigeata has a distinct denticle structure that makes morphological taxonomic inferences uncomplicated, variation of the denticles within and among individuals and populations were still observed. While traditional taxonomy of mobilines is heavily reliant on morphometrics, and recently even more so on molecular analysis, this paper proposes the use of geometric morphometry, specifically elliptical Fourier analysis, to address morphological conflicts that arise when comparing different populations. By applying this technique, combined with traditional taxonomy, it was found that T. centrostrigeata in this study can be grouped into two separate morphotypes, the first (type a) from aquaculture farms in Argentina and Mexico and the second (type b) from a natural habitat in Glen Alpine Dam, South Africa. This study supports the validity of geometric morphometry as an additional technique to distinguish not only between species but also evolutionary plasticity of the same species from different localities and habitats.

Gymnorhadinorhynchus gen. n. is proposed to accommodate its type species, G. decapteri sp. n., a parasite of the marine fish Decapterus punctatus (Cuvier), caught from the coastal waters of Brazil. Gymnorhadinorhynchus decapteri sp. n. was morphologically most similar to species of two echinorhynchid families, the Rhadinorhynchidae and the Cavisomidae, particularly in the structure of the proboscis and the absence of somatic spines, respectively. This combination of morphological features made it difficult to assign our specimen to an extant family of the Acanthocephala. Therefore, in order to clarify the systematic placement of G. decapteri, a molecular phylogenetic analysis was performed based on the SSU and LSU rDNA and the mitochondrial cox1 gene sequences obtained for the new taxon and other 26 acanthocephalan species. The results of parsimony and maximum likelihood analyses, using individual, combined and concatenated sequence data, consistently indicate that the specimens do not belong to any known family of the Echinorhynchida. Rather, G. decapteri represents a distinct lineage that is closely related to the Transvenidae, but distantly related to both the Rhadinorhynchidae and the Cavisomidae. Gymnorhadinorhynchidae fam. n. is therefore erected. This newly described family can be distinguished from other families of Echinorhynchida by the combination of the following morphological characters: a proboscis cylindrical with 10 rows of 22-26 hooks, dorsoventral differences in proboscis hooks, basal hooks forming a ring and being abruptly larger than anterior hooks, absence of trunk spines and presence of four tubular cement glands. This combination, in addition to several molecular autapomorphies, justifies the erection of a new genus, Gymnorhadinorhynchus gen. n., in order to accommodate this new species.

The intracellular parasite Toxoplasma gondii (Nicolle et Manceaux, 1908) infects humans resulting in acute toxoplasmosis, an infection that in immunocompetent people is typically mild but results in persistent latent toxoplasmosis. In that T. gondii appears to affect dopamine synthesis and because addicting drugs affect midbrain dopamine transmission, latent toxoplasmosis could influence substance use. Using both the third and continuous National Health and Nutrition Examination Surveys from the US Centers for Disease Control and Prevention, we used logistic regression to test for associations between T. gondii seropositivity and subject self-report of having ever used tobacco, alcohol, marijuana, cocaine, heroin, or methamphetamine. In the third NHANES dataset, which included data for tobacco, alcohol, marijuana and cocaine, T. gondii seropositivity was associated with a reduced likelihood of self-reported marijuana (OR = 0.71 [95% CI: 0.58; 0.87]; p = 0.001) and cocaine use (OR = 0.72 [95% CI: 0.56; 0.91]; p = 0.006). In the continuous National Health and Nutrition Examination Surveys dataset, which included data for all six substances, T. gondii seropositivity was associated with a reduced likelihood of self-reported tobacco (OR = 0.87 [95% CI: 0.76; 1.00]; p = 0.044), marijuana (OR = 0.60 [95% CI: 0.50; 0.72]; p < 0.001), heroin (OR = 0.60 [95% CI: 0.42; 0.85]; p = 0.005) and methamphetamine use (OR = 0.54 [95% CI: 0.38; 0.77]; p = 0.001). We observed interactions between sex and T. gondii seropositivity in the prediction of self-reported use of tobacco and alcohol. Further, T. gondii seropositivity appeared to remove the protective effect of education and economic status against self-reported cigarette smoking. These findings suggest that T. gondii seropositivity may be inversely associated with some but not all types of substance use in US adults.

A survey of the species of the Proteocephalus-aggregate from sticklebacks (Actinopterygii: Gasterosteidae) is provided. The occurrence of three species in North America is confirmed: (i) Proteocephalus filicollis (Rudolphi, 1802), which has been reported from the three-spined stickleback, Gasterosteus aculeatus Linnaeus, in the northeastern part of North America (Newfoundland); (ii) Proteocephalus pugetensis Hoff et Hoff, 1929 occurs also in G. aculeatus, but in northwestern North America (British Columbia and Washington); and (iii) Proteocephalus culaeae sp. n., which is described from the brook stickleback, Culaea inconstans (Kirtland), in Manitoba (Canada). Another species, Proteocephalus ambiguus (Dujardin, 1845), a specific parasite of the nine-spined stickleback, Pungitius pungitius (Linnaeus), and type species of the genus, has also been found in North America (Alberta, Canada), but its vouchers are in poor condition and cannot be reliable assigned to this species. Both species reported from three-spined stickleback differ from each other by the shape of the scolex (rounded in P. filicollis versus continuously tapered towards the anterior extremity in P. pugetensis) and the apical sucker (widely oval to subspherical in frontal view in P. filicollis versus flattened in P. pugetensis). Proteocephalus culaeae sp. n. is characterised by a short body composed of a few, continuously widened proglottids, a short scolex narrower than the strobila and devoid of an apical sucker, a short, pyriform cirrus sac, no vaginal sphincter, and few testes. A key to species of the Proteocephalus-aggregate from sticklebacks is provided.

A revisionary study revealed two species of monogeneans, Dactylogyrus crucis Rogers, 1967 and Dactylogyrus lythruri sp. n., parasitising Lythrurus Jordan (formerly a subgenus of Notropis Rafinesque, 1818). New records and updated taxonomy of seven of 12 known minnows of the genus of Lythrurus are provided for D. crucis. A record of Dactylogyrus attenuatus Mizelle et Klucka, 1953 (syn. Dactylogyrus umbratilus [Kimpel, 1939], nomen nudum) on Lythrurus umbratilis (Girard) is referrable to D. crucis. Dactylogyrus lythruri is described from eight species of Lythrurus. It most closely resembles Dactylogyrus beckeri Cloutman, 1987, but is distinguished by having a smaller base of the male copulatory organ (MCO) and lacking a ventral enlargement of the distal end of the basal process. Previous reports of Dactylogyrus banghami Mizelle et Donahue, 1944 and Dactylogyrus cf. beckeri Cloutman, 1987 from Lythrurus atrapiculus (Snelson) and Lythrurus bellus (Hay) from Alabama, and Dactylogyrus confusus Mueller, 1938 from L. umbratilis in Illinois are herein relegated to D. lythruri. Four species of Lythrurus appeared not to be infected with Dactylogyrus.

The sicklefin redhorse, Moxostoma sp. (Cypriniformes: Catostomidae), is an innominate imperiled catostomid endemic to the Hiwassee and Little Tennessee river basins, which has been restricted to a few tributaries of these systems by impoundments. During collections to propagate sicklefin redhorse for reintroduction, a myxozoan, described herein, was observed infecting sicklefin redhorse in the Little Tennessee River Basin, North Carolina. Myxobolus naylori Ksepka et Bullard sp. n. infects the stratum spongiosum covering the scales of sicklefin redhorse. Myxospores of the new species differ from all congeners by the combination of having a mucous envelope, intercapsular process, and sutural markings as well as lacking an iodinophilic vacuole in the sporoplasm. A phylogenetic analysis of the 18S rDNA gene recovered the new species in a polytomy with Myxobolus marumotoi Li et Sato, 2014 and a clade comprised of species of Myxobolus Bütschli, 1882; Thelohanellus Kudo, 1933, and Dicauda Hoffman et Walker, 1973. Histological sections of infected sicklefin redhorse skin revealed myxospores within a plasmodium in the stratum spongiosum dorsal to scales, encapsulated in collagen fibres, and associated with focal erosion of scales directly beneath the plasmodium; in some instances, the scale was perforated by the plasmodium. The specificity of the new species to sicklefin redhorse may make it a useful biological tag to differentiate sicklefin redhorse from morphologically similar species. The new species is the first parasite reported from sicklefin redhorse, a species of concern to the United States Fish and Wildlife Service. No species of Myxobolus has been reported from species of Moxostoma in the Southeast United States. As it was observed that Myxobolus minutus Rosser, Griffin, Quiniou, Alberson, Woodyard, Mischker, Greenway, Wise et Pote, 2016 is a primary junior homonym of Myxobolus minutus Nemeczek, 1911, we propose the replacement name Myxobolus diminutus (Rosser, Griffin, Quiniou, Alberson, Woodyard, Mischker, Greenway, Wise et Pote, 2016).

Strange oceanographic events such as El Niño and La Niña may have indirect effects on the local transmission processes of intestinal parasites due to the reduction or increase in populations of potential intermediate or definitive hosts. A total of 713 individuals of Lutjanus inermis (Peters) were collected over an 8-year period (October 2015 to July 2022) from Acapulco Bay, Mexico. Parasite communities in L. inermis were quantified and analysed to determine if they experienced interannual variations in species composition and structure as a result of local biotic and abiotic factors influenced by oceanographic events, such as El Niño-Southern Oscillation (ENSO), or La Niña, the cool phase of the ENSO climate pattern. Twenty-six taxa of metazoan parasites were recovered and identified: two Monogenea, eight Digenea, two Acanthocephala, four Nematoda, one Cestoda, seven Copepoda, and two Isopoda. Species richness at the component community level (8 to 17 species) was similar to reported richness in other species of Lutjanus Bloch. Parasite communities of L. inermis exhibited high inter-annual variation in the abundance of component species of parasite. However, the species richness and diversity were fairly stable over time. Climatic episodes of El Niño and La Niña probably generated notable changes in the structure of local food webs, thus indirectly influencing the transmission rates of intestinal parasite species. Changes in species composition and community structure of parasites possibly were due to variations in feeding behaviour during the events and differences in the host body size.

Parasitological examinations of 102 specimens of the lesser great cormorant Phalacrocorax carbo sinensis (Blumenbach) from two nesting regions in the Czech Republic (South Bohemia and South Moravia) were carried out at the Institute of Parasitology, Czech Academy of Sciences (previously the Czechoslovak Academy of Sciences) in the years 1987-1992. In them, a total of 19 species of helminth parasites was found, including Trematoda (11 species), Cestoda (2), Nematoda (4) and Acanthocephala (2), which can be divided into three main groups regarding their host specificity: parasites specific for cormorants (Phalacrocorax spp.) (37%), those parasitic mainly in cormorants (16%) and non-specific parasites (47%). Of the 19 species recorded, 100% were found in South Moravia, but only 47% of these 19 species in South Bohemia. The higher number of helminth species in cormorants from South Moravia and a higher proportion of non-specific species may be associated with the presence of the large Nové Mlýny water reservoir, in addition to better ecological and environmental conditions in this warmer region. Scanning electron microscopical examination of three common nematode species parasitising cormorants, Contracaecum rudolphii Hartwich, 1964, Desmidocercella incognita Solonitsin, 1932 and Syncuaria squamata (von Linstow, 1883), revealed some taxonomically important, previously unreported morphological features, such as the cephalic structures, numbers and distribution of male caudal papillae or the shapes of spicules.

Survey work of batoid elasmobranchs in the eastern Atlantic and Indo-Pacific revealed multiple species of a new genus of cestode. Stillabothrium Healy et Reyda gen. n. (Rhinebothriidea: Escherbothriidae) is unique in its possession of an even number of non-medial longitudinal septa in the posterior portion of the bothridia, resulting in a series of loculi that are longer than wide (i.e. vertically oriented) and are arranged in columns. Five new species of Stillabothrium are described, S. ashleyae Willsey et Reyda sp. n., S. davidcynthiaorum Daigler et Reyda sp. n., S. campbelli Delgado, Dedrick et Reyda sp. n., S. hyphantoseptum Herzog, Bergman et Reyda sp. n., S. jeanfortiae Forti, Aprill et Reyda sp. n., and two species are formally transferred to the genus, S. amuletum (Butler, 1987) comb. n., and S. cadenati (Euzet, 1954) comb. n., the latter of which is redescribed. The species differ in the configuration of the other bothridial septa and in proglottid anatomy. Species of Stillabothrium were found parasitising a total of 17 species of batoid elasmobranchs of the genera Dasyatis Rafinesque, Glaucostegus Bonaparte, Himantura Müller et Henle, Pastinachus Rüppell, Rhinobatos Linck and Zanobatus Garman, including several host species that are likely new to science. A phylogenetic hypothesis based on Bayesian analysis of 1 084 aligned positions of the D1-D3 region of 28S rDNA for 27 specimens representing 10 species of Stillabothrium and two outgroup species supported the monophyly of Stillabothrium. These results also supported morphologically determined species boundaries in all cases in which more than one specimen of a putative species was included in the analysis. Host specificity appears to vary across species of Stillabothrium, with the number of host species parasitised by each species of Stillabothrium ranging from one to four. The geographic distribution of species of Stillabothrium spans the eastern Hemisphere, including the eastern Atlantic (coastal Senegal) and several locations in the Indo-Pacific (coastal Vietnam, Borneo and Australia). In addition, Phyllobothrium biacetabulatum Yamaguti, 1960 is formally transferred into family Escherbothriidae, although its generic placement remains uncertain (species incertae sedis).

In the parthenogenetic monogeneans of the genus Gyrodactylus Nordmann, 1832, the genetic diversity within or between hosts is determined by the relative roles of lateral transmission and clonal propagation. Clonality and limited transmission lead to high-amplitude metapopulation dynamics and strong genetic drift. In Baltic populations of the three-spined stickleback Gasterosteus aculeatus Linnaeus, the local mitochondrial diversity of Gyrodactylus arcuatus Bychowsky, 1933 is very high, and spatial differentiation weak. To understand the transmission dynamics in a single location, the transmission of the parasite from adults to next generation sticklebacks was investigated in a northern Baltic brackish water location. By sequencing 777 nt of cox1, as many as 38 separate mitochondrial haplotypes were identified. In August, the intensity of gyrodactylid infection on adult hosts was high, the haplotype diversity (h) was extreme and differentiation between fish was negligible (total h = 0.926, mean h = 0.938). In October, only 46% of the juvenile sticklebacks carried G. arcuatus. The number of parasites per young fish followed a Poisson distribution 0.92 ± 1.04 (mean ± SD) on October 2, and was clearly overdispersed 2.38 ± 5.00 on October 25. The total haplotype diversity of parasites on juveniles was nearly as high as in adults (h = 0.916), but the mean per fish was only h = 0.364 (F_ST = 0.60), due to low intensity of infection and rapid clonal propagation of early arrivals. The initial first come first served advantage of the first gyrodactylid colonisers will be lost during the host adulthood via continuous transmission. Nesting and polygamy are suggested as factors maintaining the high genetic diversity of the parasite population. The transmission dynamics and, consequently, the population structure of Baltic G. arcuatus is fundamentally different from that of G. salaris Malmberg, 1957, on the Baltic salmon Salmo salar Linnaeus.

In the present study, we have investigated the role of antimalarial drug halofantrine (HF) in inducing the sterile protection against challenges with sporozoites of the live infectious Plasmodium yoelii (Killick-Kendrick, 1967) in Swiss mice malaria model. We observed that during the first to third sequential sporozoite inoculation cycles, blood-stage patency remains the same in the control and chemoprophylaxis under HF drug cover (CPS-HF) groups. However, a delayed blood-stage infection was observed during the fourth and fifth sporozoite challenges and complete sterile protection was produced following the sixth sporozoite challenge in CPS-HF mice. We also noticed a steady decline in liver stage parasite load after 3th to 6th sporozoite challenge cycle in CPS-HF mice. CPS-HF immunisation results in a significant up-regulation of pro-inflammatory cytokines (IFN-γ, TNF-α, IL-12 and iNOS) and down-regulation of anti-inflammatory cytokines (IL-10 and TGF-β) mRNA expression in hepatic mononuclear cells (HMNC) and spleen cells in the immunised CPS-HF mice (after 6th sporozoite challenge) compared to control. Overall, our study suggests that the repetitive sporozoite inoculation under HF drug treatment develops a strong immune response that confers protection against subsequent challenges with sporozoites of P. yoelii.

A new haemogregarine species Hepatozoon affluomaloti sp. n. is described from erythrocytes in the peripheral blood of crag lizards Pseudocordylus melanotus (Smith) and Pseudocordylus subviridis (Smith) (Sauria: Cordylidae) from mountainous regions in the Eastern Free State, South Africa. This species can be distinguished from all other congeners based on its large size, staining properties and life cycle development in its vector, Culex (Afroculex) lineata (Theobald) (Diptera: Culicidae). Mature gamonts stain mostly uniformly pinkish-purple with Giemsa, sometimes containing darker azurophilic granules anterior and posterior to the nucleus. The reflexed posterior extremity of the gamont stage sometimes stains slightly deeper purple and the nucleus is dense and placed in the posterior third of the parasite body. Merogonic stages of this haemogregarine occur in the liver tissues of P. melanotus with dizoic meronts. Macromeronts contains 2-7 macromerozoites and micromeronts contains 9-24 micromerozoites. Sporogonic developmental stages found in the proposed final host and vector, C. lineata, include large oocysts, measuring 54 × 48 µm on average. Sporulating oocysts with 8 nuclei are present in mosquitoes 6-7 days post-feeding on infected lizards. Sporocysts with mature sporozoites measure 31.0 × 21.8 µm on average and each contains 2-8 large sporozoites. It is suggested that transmission of infective sporozoites is achieved through predation of lizards on mosquitoes.

Synbranchiella gen. n. is proposed to accommodate Synbranchiella mabelae sp. n. (Proteocephalidae: Monticelliinae) from the intestine of the marbled swamp eel Synbranchus marmoratus Bloch, in the River Colastiné, a tributary of the middle River Paraná in Argentina. The new genus is placed in the Monticelliinae because of the cortical position of the genital organs. It differs from all known monticelliine genera by the following combination of characters: (i) scolex robust, with a conical apex, without metascolex; (ii) biloculate suckers with a conspicuous septum separating unequally-sized loculi and a robust non-adherent area, lacking free posterior margin; (iii) vitelline follicles in two narrow lateral bands, extended throughout the nearly entire proglottid length; (iv) vagina always anterior to the cirrus-sac, with an inconspicuous vaginal sphincter; (v) a genital pore pre-equatorial. Scanning electron microscopy revealed three types of microtriches on the tegument surface: acicular and capiliform filitriches and gladiate spinitriches. A phylogenetic analysis of the large subunit nuclear ribosomal RNA gene (lsrDNA, D1-D3 domains) confirms that S. mabelae represents an independent lineage within a large clade comprised mainly from Neotropical taxa parasitising catfishes. This is the second proteocephalidean cestode described from a Neotropical synbranchiform fish host.

The distribution, variability and host specificity of species of Babesia Starcovici, 1893 were studied in questing ticks collected on the northwestern edge of the Pannonian Basin in the south-easternmost part of the Czech Republic and in western Slovakia. The area is characterised by relatively natural floodplain habitats and the sympatric occurrence of three tick species possessing wide host spectra, namely Ixodes ricinus (Linnaeus), Dermacentor reticulatus (Fabricius) and Haemaphysalis concinna Koch. Analysis was carried out on 1,408 I. ricinus, 2,999 D. reticulatus and 150 H. concinna altogether, collected from 59 localities. We documented the presence of Babesia spp. not only in I. ricinus but also in H. concinna in the Czech Republic. Two isolates from I. ricinus were classified as B. venatorum Herwaldt, Cacciò, Gherlinzoni, Aspöck, Slemenda, Piccaluga, Martinelli, Edelhofer, Hollenstein, Poletti, Pampiglione, Löschenberger, Tura et Pieniazek, 2003 (formerly determined as Babesia sp. EU1), which is a zoonotic parasite and can cause human babesiosis. The rest of our amplicons were very similar to B. canis (Piana et Galli-Valerio, 1895), which is usually transmitted by D. reticulatus. Despite the huge amount of examined samples, all D. reticulatus ticks were Babesia-free. Due to this finding, we did not consider our obtained isolates to be B. canis, but other closely related species possessing a similar sequence of the studied portion of 18S rDNA. Although this genetic marker is most frequently used in PCR-based diagnostic methods of babesias, its low variability compromises its reliability in studies based only on this marker.

In Italy, food-borne outbreaks of opisthorchiasis have occurred since 2003, all of them originating from some lakes in Central Italy where the only European liver fluke, Opisthorchis felineus (Rivolta, 1884) is endemic. The aim of the present study is to investigate the factors that may facilitate the life cycle of O. felineus in the area of Bolsena Lake, the knowledge of the local population about opisthorchiasis, and preventative healthcare measures. We performed a descriptive observational study through the submission of questionnaires to three target populations: fishermen who fish exclusively in Bolsena Lake, restaurateurs whose businesses are close to the lake and general population living in the province of Viterbo. Results showed hazardous behaviours and eating habits in the three target populations, as well as a poor knowledge of opisthorchiasis and preventative healthcare measures.

The first molecular assessment of phylogenetic relationships of cladorchiid digeneans (superfamily Paramphistomoidea Fischoeder, 1901) from freshwater fishes based on 28S rDNA, ITS2 and cox1 sequences reveals the subfamilies Dadayiinae Fukui, 1929 and Kalitrematinae Travassos, 1933 as non-monophyletic, whereas Dadaytrema Travassos, 1931 represented by three species is monophyletic. Fourteen species of cladorchiids were found in characiform, perciform and siluriform fishes in the Neotropical Region (Brazil and Peru), with numerous new host and geographical records. The first scanning electron micrographs of seven species are presented. Two new species of dadayiine and one new species of kalitrematine paramphistomes are described. Microrchis macrovarium sp. n. from Pimelodella cristata (Müller et Troschel) (type host), Tetranematichthys quadrifilis (Kner) and Pterodoras granulosus (Valenciennes) in Brazil and Peru differs from all three congeners in that the testes are directly tandem, not oblique, and that the ovary, between the caecal ends, is widely separated from the testes. Pronamphistoma philippei sp. n. from Heros sp. in Brazil is distinguished from the type and only species, Pronamphistoma cichlasomae Thatcher, 1992, by the absence of the anterior collar-like expansion present in the type species, the presence of extramural rather than intramural pharyngeal sacs, and the unusual development of the dorsal and ventral exterior circular muscle fibre series in the acetabulum. Pseudocladorchis romani sp. n. from P. granulosus (type host), Brachyplatystoma vaillantii (Valenciennes), Calophysus macropterus (Lichtenstein), Megalodoras uranoscopus (Eigenmann et Eigenmann) and Oxydoras niger (Valenciennes) in Brazil and Peru, is most similar to Pseudocladorchis nephrodorchis Daday, 1907 but differs in the shape of the testes (irregular, versus reniform in the latter species) and the size of the ovary (as large as, or larger than, the testes in the new species). The generic diagnosis of Pronamphistoma Thatcher, 1992 is amended. Dadaytremoides parauchenipteri Lunaschi, 1989 is transferred to Doradamphistoma Thatcher, 1979 as D. parauchenipteri (Lunaschi, 1989) comb. n. based on morphological and molecular evidence.

A three-year-old male South China tiger died in the tiger enclosure of the China Tiger Park in the Meihua Mountains on December 2018 after being bitten by a tick. This tiger presented clinical symptoms like whole-body severe jaundice, hepatosplenomegaly, kidney, and lymph node hemorrhages. The Colpodella sp.-specific 18S rRNA gene was detected using nested PCR. Interestingly, the DNA isolated from the blood of the tiger was found to be 100% similar to that of the tick by NCBI BLAST analysis. However, the DNA fragments isolated from the tiger's blood were 90.1% similar to the Colpodella sp. strain human erythrocyte parasite (HEP, MH208621) and 90.4% similar to the Colpodella sp. strain Heilongjiang (HLJ, KT364261). To investigate the species of ticks and ticks-carried Colpodella parasites in this region, the species of ticks obtained from the grasses outside the tiger enclosure and the species of Colpodella carried by ticks were identified. The DNA from ticks as well as that from the tick-borne Colpodella sp. were amplified from each tick using PCR followed by amplicon sequencing. In total 402 adult ticks samples were collected, among which 22 were positive for Colpodella sp. (5.5%), and the species were further determined by morphology, DNA sequencing and phylogenetic analyses. Interestingly, one Colpodella sp. was found to have 94.2% sequence similarities to the Colpodella sp. strain HEP (MH208621). This strain was previously reported to infect a woman in Yunnan, China. In addition, three Colpodella sp. showed 87-91% sequence similarities to the Colpodella sp. strain HLJ (KT364261), which was previously reported to infect human in Heilongjiang, China. This study disclosed the possibility of zoonotic transmission of Colpodella sp. by ticks in China. Finally, it provides a basis for urgently determining and monitoring the repertoire of ticks-borne piroplasmid pathogens, with the ultimate aim of strategic control.