Most host-parasite associations are explained by phylogenetically conservative capabilities for host utilization, and therefore parasite switches between distantly related hosts are rare. Here we report the first evidence of a parasitic spillover of the burrowing sea anemone Edwardsiella carnea from the invasive ctenophore Mnemiopsis leidyi to two scyphozoan hosts: the native Mediterranean barrel jellyfish Rhizostoma pulmo and the invasive Indo-Pacific nomad jellyfish Rhopilema nomadica, collected from the Eastern Mediterranean Sea. Edwardsiella carnea planulae found in these jellyfish were identified using molecular analyses of the mitochondrial 16S and nuclear 18S rRNA genes. Overall, 93 planulae were found on tentacles, oral arms, and inside of the gastrovascular canals of the scyphomedusae, whereas no infection was observed in co-occurring ctenophores. DNA metabarcoding approach indicated seasonal presence of Edwardsiella sp. in the Eastern Mediterranean mesozooplankton, coinciding with jellyfish blooms in the region. Our findings suggest a non-specific parasitic relationship between Edwardsiella carnea and various gelatinous hosts based on shared functionality rather than evolutionary history, potentially driven by shifts in host availability due to jellyfish blooms. This spillover raises questions about the ecological impacts of parasitism on native and invasive scyphozoan hosts and the potential role of Edwardsiella in controlling their populations.

BACKGROUND: Brazil has a high prevalence of toxoplasmosis. However, there is a gap in comparing seroprevalence for Toxoplasma gondii across different environments, particularly among pregnant residents of rural and urban areas.
METHODS: The prevalence of IgG and IgM for T. gondii was compared among pregnant residents of the urban, peri-urban, and rural settlement areas in a municipality in southeastern Brazil. Information regarding age and area of residence was compiled from January 2015 to December 2022. Logistic regression analysis was used to assess the age and area of residence as risk factors.
RESULTS: A total of 1614 examinations were recorded, revealing 54.0% seropositivity, which was highest in the rural settlement (61.1%), followed by the peri-urban area (55.9%), and lowest in the urban area (49.2%).
CONCLUSIONS: The high prevalence of IgG and presence of IgM in pregnant residents of rural, peri-urban, and urban areas highlights the significance of the results obtained for strengthening maternal health programs aimed at preventing toxoplasmosis, regardless of their residence.

Specimens of a caligid copepod (Siphonostomatoida) were found on the gills of the hairfin lookdown Selenebrevoortii (Gill) (Carangidae) from off Mazatlán, Sinaloa (north-western Mexico). This material represents a new species of Caligus, C.selenecola sp. nov., and is assigned to the diaphanus species group. Within this group, only C.kapuhili Lewis, 1967, C.laticaudus Shiino, 1960, C.macrurus Heller, 1865, and C.selenecola sp. nov., have been described with a reduced outer spine 1 on the second exopodal segment of leg 1. These four species can be readily separated by the relative length of the abdomen, and the presence/absence of a process on the myxal area of the female maxilliped, the sternal furca, the postantennal process, and the spiniform process on the basal antennary segment. A full description of the new species is given with some comments on Caritustolii Rangnekar, 1984.

The human parasitic fluke, Schistosoma haematobium hybridizes with the livestock parasite S. bovis in the laboratory, but the extent of hybridization in nature is unclear. We analyzed 34.6 million single nucleotide variants in 162 samples from 18 African countries, revealing a sharp genetic discontinuity between northern and southern S. haematobium. We found no evidence for recent hybridization. Instead the data reveal admixture events that occurred 257-879 generations ago in northern S. haematobium populations. Fifteen introgressed S. bovis genes are approaching fixation in northern S. haematobium with four genes potentially driving adaptation. We identified 19 regions that were resistant to introgression; these were enriched on the sex chromosomes. These results (i) demonstrate strong barriers to gene flow between these species, (ii) indicate that hybridization may be less common than currently envisaged, but (iii) reveal profound genomic consequences of interspecific hybridization between schistosomes of medical and veterinary importance.

UNASSIGNED: Genomic analysis has revealed extensive contamination among laboratory-maintained microbes including malaria parasites, Mycobacterium tuberculosis and Salmonella spp. Here, we provide direct evidence for recent contamination of a laboratory schistosome parasite population, and we investigate its genomic consequences. The Brazilian Schistosoma mansoni population SmBRE has several distinctive phenotypes, showing poor infectivity, reduced sporocysts number, low levels of cercarial shedding and low virulence in the intermediate snail host, and low worm burden and low fecundity in the vertebrate rodent host. In 2021 we observed a rapid change in SmBRE parasite phenotypes, with a ~10x increase in cercarial production and ~4x increase in worm burden.
UNASSIGNED: To determine the underlying genomic cause of these changes, we sequenced pools of SmBRE adults collected during parasite maintenance between 2015 and 2023. We also sequenced another parasite population (SmLE) maintained alongside SmBRE without phenotypic changes.
UNASSIGNED: While SmLE allele frequencies remained stable over the eight-year period, we observed sudden changes in allele frequency across the genome in SmBRE between July 2021 and February 2023, consistent with expectations of laboratory contamination. (i) SmLE-specific alleles rose in the SmBRE population from 0 to 41-46% across the genome between September and October 2021, documenting the timing and magnitude of the contamination event. (ii) After contamination, strong selection (s = ~0.23) drove replacement of low fitness SmBRE with high fitness SmLE alleles. (iii) Allele frequency changed rapidly across the whole genome, except for a region on chromosome 4 where SmBRE alleles remained at high frequency.
UNASSIGNED: We were able to detect contamination in this case because SmBRE shows distinctive phenotypes. However, this would likely have been missed with phenotypically similar parasites. These results provide a cautionary tale about the importance of tracking the identity of parasite populations, but also showcase a simple approach to monitor changes within populations using molecular profiling of pooled population samples to characterize fixed single nucleotide polymorphisms. We also show that genetic drift results in continuous change even in the absence of contamination, causing parasites maintained in different labs (or sampled from the same lab at different times) to diverge.

Three stations along the Ase River, Delta State Nigeria provided water and 85 fish samples which were analyzed. The fish were measured and examined for endoparasites according to established protocol. All water quality parameters investigated were within the WHO-acceptable values for surface waters. Station variation of physicochemical parameters was not statistically significant (p > 0.05). Fish body conformation indices positively correlated with the prevalence of parasites in Clarias gariepinus, Heterobranchus longifilis, Parachana africana, Chromidotilapia guntheri guntherii, and Denticeps clupeodes. The overall parasite prevalence of 63.53% was established with the most abundant parasite being Trichodina mutabillis. The parasites had a predilection for the gastrointestinal tract with a high occurrence of 307 individuals. Stations 1, 2, and 3 had 326, 213, and 259 parasites, respectively, out of a total of 798 parasites detected. P. laevis was absent in station 1. All parasites were found in stations 2 and 3. Statistically, there was a significant difference (p < 0.05) in the prevalence in all stations. The correlation index of T. mutabillis and R. congolensis in stations 1 and 3 was positively strong (p < 0.05) with the concentrations of water quality. However, water conditions in stations 1 and 3 had a deleterious impact on P. laevis. T. mutabillis maintained a high positive correlation with physicochemical water quality in all three stations. Shannon-Weiner\'s index in station 3 (H = 1.337) shows that the parasites were more diverse. PCA and biodiversity indices have enabled us to comprehend how parasite-host-environment systems interact.

Fisheries play a crucial role in aquatic ecosystems, a resource with ecological and economic importance. Measuring parasite prevalence is necessary to assess these fish species\' health and well-being. Within the Sistan region, this study sought to estimate the prevalence and intensity of infection with plerocercoid Ligula intestinalis (L. intestinalis) in seven fish species and identify factors such as fish weight, seasonality, and fishing location that might influence infection rates. 2800 fish from seven species were obtained in the Sistan region throughout four seasons. Fish samples from three weight categories (<200gr, 200-400gr, 400gr<) were examined parasitologically. Ligula intestinalis was detected in 96/2800 (3.4%) of fishs. There was a variation in prevalence among fish species. Alburnus charusini (A. charusini), Hypophthalmichthys molitrix (H. molitrix), Hypophthalmichthys nobilis (H. nobilis), and Schizocypris altidorsalis (S. altidorsalis) showed no infection. Schizothorax zarudnyi (S. zarudnyi) showed a prevalence of 1.5% (6/400), Cyprinus carpio (C. carpio) 15% (60/400), and Ctenopharyngodon idella (C. idella) 7.5% (30/400). It was found that infection prevalence was significantly influenced by fish weight in C . carpio and C . idella. A higher prevalence was found in fish with lower weight. Infection rates significantly fluctuated with season across species, but fishing locations had no significant difference. The present study highlights the significant prevalence of L. intestinalis infections in fish populations within Iran\'s Sistan region, underscoring the need for ongoing monitoring and research to inform effective fishery management strategies. Future studies should focus on long-term monitoring efforts and consider the broader global context of fish parasitology to understand parasite-host interactions better and inform conservation measures worldwide.
UNASSIGNED:

UNASSIGNED: Tickborne diseases have become the threats to the health of people worldwide, accounting for nearly 80% patients with vectorborne diseases in the United States. Early diagnosis and proper treatment play a significant role in the management. Close contacts should be screened for delayed symptoms associated with tickborne diseases.
UNASSIGNED: This study describes a rare case of a 72-year-old Chinese man presented with a 5-day history of painful nodules on the perianal region, indicating tick bite. Tickborne diseases become the threats to the health of people worldwide. Untreated cases may result in several serious inflammatory complications. Manual removal of ticks with fine forceps is effective for preventing the transmission of tickborne infections. People (who have been bitten by a tick) and close contacts should be screened for delayed symptoms associated with tickborne diseases.

African cichlids are model systems for evolutionary studies and host-parasite interactions, because of their adaptive radiations and because they harbour many species of monogenean parasites with high host-specificity. Five locations were sampled in southern Lake Victoria: gill-infecting monogeneans were surveyed from 18 cichlid species belonging to this radiation superflock and two others representing two older and distantly related lineages. We found one species of Gyrodactylidae, Gyrodactylus sturmbaueri Vanhove, Snoeks, Volckaert & Huyse, 2011, and seven species of Dactylogyridae. Four are described herein: Cichlidogyrus pseudodossoui n. sp., Cichlidogyrus nyanza n. sp., Cichlidogyrus furu n. sp., and Cichlidogyrus vetusmolendarius n. sp. Another Cichlidogyrus species is reported but not formally described (low number of specimens, morphological similarity with C. furu n. sp.). Two other species are redescribed: C. bifurcatus Paperna, 1960 and C. longipenis Paperna & Thurston, 1969. Our results confirm that the monogenean fauna of Victorian littoral cichlids displays lower species richness and lower host-specificity than that of Lake Tanganyika littoral cichlids. In C. furu n. sp., hooks V are clearly longer than the others, highlighting the need to re-evaluate the current classification system that considers hook pairs III-VII as rather uniform. Some morphological features of C. bifurcatus, C. longipenis, and C. nyanza n. sp. suggest that these are closely related to congeners that infect other haplochromines. Morphological traits indicate that representatives of Cichlidogyrus colonised Lake Victoria haplochromines or their ancestors at least twice, which is in line with the Lake Victoria superflock being colonised by two cichlid tribes (Haplochromini and Oreochromini).
UNASSIGNED: Quatre espèces nouvelles de Cichlidogyrus (Plathelminthes, Monopisthocotyla, Dactylogyridae) parasites d’haplochrominés (Cichlidae) du lac Victoria, avec la redescription de C. bifurcatus et C. longipenis.
UNASSIGNED: Les cichlidés africains sont des systèmes modèles pour les études évolutives et les interactions hôtes-parasites, en raison de leurs radiations adaptatives et parce qu’ils hébergent de nombreuses espèces de monogènes parasites avec une spécificité d’hôte étroite. Cinq sites ont été échantillonnés dans le sud du lac Victoria, les monogènes infectant les branchies ont été étudiés chez 18 espèces de cichlidés appartenant à ce superflock et de deux autres espèces représentant deux lignées plus anciennes et éloignées. Nous avons trouvé une espèce de Gyrodactylidae, Gyrodactylus sturmbaueri Vanhove, Snoeks, Volckaert & Huyse, 2011, et sept espèces de Dactylogyridae. Quatre sont décrites ici : Cichlidogyrus pseudodossoui n. sp., Cichlidogyrus nyanza n. sp., Cichlidogyrus furu n. sp. et Cichlidogyrus vetusmolendarius n. sp. Une autre espèce de Cichlidogyrus est signalée mais non formellement décrite (faible nombre de spécimens, similarité morphologique avec C. furu n. sp.). Deux autres espèces sont redécrites : C. bifurcatus Paperna, 1960 et C. longipenis Paperna & Thurston, 1969. Nos résultats confirment que la faune des monogènes des cichlidés du littoral du lac Victoria présente une richesse en espèces et une spécificité d’hôte inférieures à celles des cichlidés du littoral du lac Tanganyika. Chez C. furu n. sp., les crochets V sont clairement plus longs que les autres, ce qui souligne la nécessité de réévaluer le système de classification actuel qui considère que les crochets III-VII sont plutôt uniformes. Certaines caractéristiques morphologiques de C. bifurcatus, C. longipenis et C. nyanza n. sp. suggèrent que ceux-ci sont étroitement liés aux congénères qui infectent les autres haplochrominés. Les traits morphologiques indiquent que les représentants de Cichlidogyrus ont colonisé les haplochrominés du lac Victoria ou leurs ancêtres au moins deux fois, ce qui concorde avec le fait que le superflock du lac Victoria a été colonisé par deux tribus de cichlidés (Haplochromini et Oreochromini).

Toxoplasma gondii is a widely distributed apicomplexan parasite causing toxoplasmosis, a critical health issue for immunocompromised individuals and for congenitally infected foetuses. Current treatment options are limited in number and associated with severe side effects. Thus, novel anti-toxoplasma agents need to be identified and developed. 1-Deoxy-d-xylulose 5-phosphate reductoisomerase (DXR) is considered the rate-limiting enzyme in the non-mevalonate pathway for the biosynthesis of the isoprenoid precursors isopentenyl pyrophosphate and dimethylallyl pyrophosphate in the parasite, and has been previously investigated for its key role as a novel drug target in some species, encompassing Plasmodia, Mycobacteria and Escherichia coli. In this study, we present the first crystal structure of T. gondii DXR (TgDXR) in a tertiary complex with the inhibitor fosmidomycin and the cofactor NADPH in dimeric conformation at 2.5 Å resolution revealing the inhibitor binding mode. In addition, we biologically characterize reverse α-phenyl-β-thia and β-oxa fosmidomycin analogues and show that some derivatives are strong inhibitors of TgDXR which also, in contrast with fosmidomycin, inhibit the growth of T. gondii in vitro. Here, ((3,4-dichlorophenyl)((2-(hydroxy(methyl)amino)-2-oxoethyl)thio)methyl)phosphonic acid was identified as the most potent anti T. gondii compound. These findings will enable the future design and development of more potent anti-toxoplasma DXR inhibitors.