Paraxerus cepapi is an arboreal tree squirrel that occurs in the Savanna biome of Africa, and information on its parasite diversity is limited and mostly qualitative. The aim of the study was to record the diversity and abundance of ecto- and helminth parasites associated with P. cepapi across its distribution in South Africa. P. cepapi individuals (n = 94) were opportunistically obtained from eight localities during 2020 to 2024. In total, 21 parasite species (19 ectoparasites and two nematodes) and one tick species group were identified. This included lice, ticks, fleas, a mesostigmatic mite, chiggers, nematodes and cestodes. Nematodes were the most prevalent (93·67%), followed by lice (80·85%). Syphatineria cepapi was recorded in 92·41% of P. cepapi, while an unknown Strongyloides species, resembling S. robustus, was recorded in 21·52% of squirrels. The lice species displayed variation in parasitope preference, while chiggers were primarily recorded in the ears. This study provides new country records for the lice species Werneckia paraxeri and Enderleinellus heliosciuri, for the chigger species Microtrombicula polymorpha, and for the nematode S. cf. robustus. New locality records were documented for the nematode S. cepapi in South Africa, and P. cepapi is a new host record for the eight chigger species and S. cf. robustus. It is evident that P. cepapi in South Africa hosts a considerably larger diversity of parasite taxa than previously recorded. Nematode counts were related to host length. These findings warrant future studies on the parasite diversity of P. cepapi in Africa.

We applied 2 methods of phylogenetic regionalization (evoregions and phyloregions) for the distributions of fleas and their rodent hosts across Mongolia. We investigated the congruence between these 2 regionalization schemes and their alignment with physiographic and ecological subdivisions of Mongolia. We identified evoregions and phyloregions for both fleas and hosts. Ancestral regional distributions were reconstructed, and a phylogenetic correspondence analysis identified key contributing lineages. Using the V-measure, we tested for the congruence between (a) evoregions or phyloregions identified for fleas and evoregions or phyloregions, respectively, identified for their hosts and (b) evoregions and phyloregions identified for either fleas or hosts and each of the physiographic/ecological regionalization schemes of Mongolia. Four evoregions and 8 phyloregions were identified for both fleas and hosts, exhibiting distinct spatial patterns. Host-parasite regionalizations demonstrated moderate spatial similarity (V-measure 0.49–0.50), a significantly higher congruence than previously reported at the larger Palearctic scale (0.33). Flea regionalizations exhibited stronger congruence with environmental schemes than did host regionalizations. We concluded that evoregionalization and phyloregionalization capture distinct evolutionary signals, reflecting the role of in situ diversification vs. phylogenetic turnover resulting from dispersal. Host-parasite co-regionalization is scale-dependent, with increased congruence at regional scales. Despite adult fleas’ obligate host dependence, their regionalization is not merely a passive reflection of host biogeography but is also profoundly shaped by environmental conditions. These findings emphasize the importance of method choice, scale and eco-evolutionary interactions in shaping complex biogeographic patterns.

Urogenital schistosomiasis has 2 gender-specific manifestations, male genital schistosomiasis (MGS) and female genital schistosomiasis (FGS). The burdens of MGS and FGS are multifaceted, encompassing financial hardship, emotional and mental health problems and sometimes social stigmatization. Given the pernicious nature of sequelae in the genitalia, managing these chronic health conditions is expensive, difficult and problematic in resource poor settings. Key challenges include lack of epidemiological data on the burden of MGS and FGS, inadequate knowledge among primary and auxiliary health care workers, leading to misdiagnosis, incorrect treatment administration, e.g. overuse of antibiotics, and a lack of appropriate point-of-care diagnostic equipment. Prevention of MGS and FGS is therefore more preferable, however, current preventive programmes and chemotherapy campaigns offering praziquantel are becoming more resource constrained and in most endemic areas are not reaching at-risk adults (and adolescents), sufficiently. Furthermore, there are limited prospects for adequate access to treatment in pre-school children where infections can be first acquired. Therefore, we propose 3 key recommendations guiding movement towards elimination of schistosomiasis as a public health problem: scaling-up praziquantel treatment for other at-risk groups; developing a targeted One Health approach to reduce environmental transmission in both humans and animals; Multi-stakeholder collaboration and community engagement for effective implementation of Water Sanitation and Hygiene components of disease control. Whilst maintaining a school-based approach is still foundational, targeted and sustainable expansion of preventive chemotherapy to other at-risk groups within communities is needed to secure real prospects in elimination of genital schistosomiasis as a public health problem in Africa.

The prevalence of female genital schistosomiasis (FGS) and male genital schistosomiasis (MGS) remains high in many low-to-medium-income countries, and each has sex-specific disease sequelae with wider detrimental gender and health impacts. Social science research studies on the former outnumber those on the latter. Indeed, in many countries across sub-Saharan Africa (SSA), MGS (as with male reproductive and sexual health issues in general) is overlooked, underappreciated, and broadly orphaned within urogenital and intestinal schistosomiasis research and control. Similarly, in those countries where MGS has been reported formally, its psychosocial dimensions and effects remain poorly understood, especially in terms of context-specific cultural and societal factors. In this scoping review, we attempt to better contextualize MGS within men’s sexual and reproductive health and rights (SRHR) and general wellbeing, as it often draws parallels with social science research in FGS. We discuss common psychosocial determinants, highlighting why current surveillance of MGS is particularly poor and the primary health care response to mitigate it is bottlenecked and largely stalled within the wider health system, from both top-down and bottom-up perspectives. Our specific approach remains cognisant of the context of infected households where all members could be suffering from urogenital and/or intestinal schistosomiasis. Looking ahead, we develop and frame a pragmatic social science research agenda to encourage and better explore and assess the detrimental impact of MGS on infected men and boys, considering appropriate ameliorations more holistically within primary care.

Besnoitia besnoiti is an apicomplexan parasite, the causal agent of bovine besnoitiosis. This disease is characterised by cyst formation in the skin and mucosa. During early infection, fast proliferating tachyzoites invade and replicate within host endothelial cells. In non-excitable cells, extracellular signals activate the inositol-triphosphate/calcium (InsP3/Ca2+) pathway, which depends on phospholipase C (PLC) activation, inducing an increase in IP3 levels, followed by intracellular Ca2+ release. Despite the understanding of Ca2+ signalling, this process in B. besnoiti tachyzoites is unclear. This work aimed to study Ca2+ dynamics during B. besnoiti infection in bovine umbilical vein endothelial cells (BUVEC) and the role of the InsP3/Ca2+ pathway during B. besnoiti infection. Ca2+ dynamics during tachyzoite replication were determined in B. besnoiti-infected BUVEC loaded with fluo-4-AM. The role of InsP3/Ca2+ signalling for parasite invasion was evaluated by treatments with Ca2+ chelators (BAPTA, EGTA) or PLC inhibitors (U73122, D609). PLC activation was studied in fluo-4-loaded free tachyzoites using the PLC activator m-3M3FBS, in the presence or absence of PLC inhibitors. Current data show an infection-driven increase in total Ca2+ signals in B. besnoiti-infected BUVEC over time. BAPTA, but not EGTA, treatments of tachyzoites affected their invasion, reducing infection rates by 85.4 ± 9.3%, suggesting that intracellular Ca2+ sources are necessary for B. besnoiti invasion. In line, treatments with U73122 and D609 reduced infection rates by 79.3 ± 9.4% and 49.7 ± 8.9%, respectively, demonstrating that PLC participation is required for host cell infection. Finally, m-3M3FBS treatments induced a PLC-independent Ca2+ flux in B. besnoiti tachyzoites.

Parasite transmission can be disrupted when their free-living larval stages are consumed by non-host organisms. Yet, the contribution of benthic scrapers to this process remains insufficiently explored. Here, we experimentally assessed the ability of the North American pulmonate snail Physa acuta to reduce the abundance of free-living digenean larvae – cercariae of Diplostomum sp. and Trichobilharzia sp., and adolescariae of Notocotylus sp. – and evaluated how this effect is modulated by snail body size and colonisation by other organisms. Larval consumption by P. acuta occurred in all treatments and was highest for settled Notocotylus sp. adolescariae, particularly among larger individuals. The extent of larval reduction varied with infection by digenean metacercariae (xiphidiometacercariae), which either enhanced or inhibited feeding depending on parasite identity. It also varied with colonisation by Chaetogaster limnaei limnaei, whose presence increased the ingestion of planktonic cercariae, likely due to the combined feeding activity of the snail and its commensal oligochaete. Most snails harboured metacercariae, indicating that P. acuta frequently functions as a second intermediate host in its non-native range. Our findings highlight the dual ecological role of P. acuta – both as a consumer of free-living parasite stages and as a competent host. This trophic interaction may disrupt parasite transmission while providing nutritional benefits that support the ecological success and spread of this non-native species. Conversely, by serving as a host, P. acuta may facilitate the persistence and dissemination of parasitic taxa in invaded ecosystems.

The digenean trematode, Corrigia vitta, is a frequently reported component species in studies of helminth communities of wild rodents in Europe, especially those of wood mice and bank voles. It has been known since Dujardin first described the species in 1845, and yet its life cycle is still poorly defined, although Dicrocoeliidae typically have at least 3 hosts in their life cycles. Here, we review the history of nomenclature changes of the species, morphological studies, definitive mammalian host species range and evidence for the identity of intermediate hosts. We also review the epidemiology of C. vitta, searching for commonalities between studies that have assessed the effects of intrinsic and extrinsic variables on both prevalence and abundance of the species in wood mice. Furthermore, we identify gaps in knowledge and propose key objectives for future work on the species. We emphasize that if the life cycle of C. vitta could be established in the laboratory and maintained in laboratory mice, as a hepatopancreatic specialist in its definitive host, the parasite may turn out to be the source of novel medicines for the treatment of human pancreatic/liver diseases.

Liberia (West Africa) has an extensive (co)burden of urogenital and intestinal schistosomiasis; each largely restricted to more inland areas. Where urogenital schistosomiasis is endemic, as both disease surveillance and case management are nascent, many women may unknowingly be living with Female Genital Schistosomiasis (FGS). Using a recently developed FGS score card, we appraised FGS score card valuations with point-of-care gynaecological and molecular parasitological evaluations as undertaken within typical primary care settings of four Liberian counties. A total of 400 women, 100 participants from each of four endemic inland counties, underwent a cursory gynaecological examination using a speculum for visible FGS lesions, undertaken by a midwife, and provided a urine sample that was examined by centrifugation with microscopy for Schistosoma ova. Urine-sediments in ethanol were later analysed with a high-resolution melt (HRM) real-time (rt) PCR assay to screen for Schistosoma genetic markers. Using a combination of clinical and parasitological information, overall prevalence of UGS and FGS was <10% and a single case of putative FGS-associated co-infection with Schistosoma mansoni was observed. Participant interviews with the FGS score cards provided an insight into at-risk lifestyle and environmental factors, e.g. women who fished regularly were more likely to present with FGS whereas those who lived > 15 km from a local river were less likely to present with FGS. In this resource-poor setting of Liberia, active surveillance for FGS with either clinical or parasitological methods remains challenging such that sole future use of the FGS score card is most pragmatic for primary care.

The nematode genus Rhabdias comprises over 100 species of parasitic nematodes that infect amphibians and reptiles, with a wide geographical distribution. To date, 25 species have been reported from the Neotropical region. Despite this diversity, few integrative studies, combining morphological and molecular data have been conducted to characterize species within the genus. Therefore, the main objective of the present study is to describe, through an integrative approach, a new species of Rhabdias found parasitizing the lungs of an anuran with a high concentration of skin toxins, Dendrobates tinctorius, from the Brazilian Amazon. The new species of Rhabdias is characterized by an elongated body, uniform cuticular inflation attenuated at the extremities, 4 submedian lips and 2 lateral lips, a cup-shaped buccal capsule, and an elongated tail. The morphology of the buccal capsule in Rhabdias camposi n. sp. is also unique among Rhabdias representatives, as this morphological character is known so far. Thus, we emphasize that a detailed study of this morphological trait for species of the genus will be crucial for species diagnosis. Molecular and phylogenetic analyses were performed using mitochondrial COI gene sequences. We observed that the new taxon is closely related to Rhabdias waiapi, a parasite of Pristimantis chiastonotus. Rhabdias camposi n. sp. represents the 26th species of the genus reported from the Neotropics in amphibians and the first described from a Dendrobates tinctorius host in Brazil.

Phlebotomine sand flies are found across multiple regions of Thailand, with growing recognition of their role in transmitting zoonotic pathogens. Environmental factors, including climate variability and vector ecology, may influence their distribution and activity, contributing to the potential spread of zoonotic pathogens in Southeast Asia. However, comprehensive data on sand fly distribution in Thailand remain limited. To address this gap, a systematic review was conducted following PRISMA guidelines. Out of 112 records retrieved, 33 met the inclusion criteria and quality assessment for further analysis. As per results, sand flies are widespread in Thailand, with a high level of species diversity comprising 42 species of 6 different genera. However, several provinces lack data on the presence and distribution of sand flies. Eleven species were identified as the overall abundant species throughout the studies from January 2007 to June 2025 and grouped by abundance: low-abundance species (Sergentomyia barguesae, Sergentomyia phadangensis, Sergentomyia barraudi and Sergentomyia indica), abundant but understudied species (Sergentomyia sylvatica, Sergentomyia anodontis and Neopulpus vietnamensis) and most abundant species (Sergentomyia hodgsoni, Sergentomyia gemmea, Sergentomyia iyengari and Sergentomyia khawi). From the most abundant species, S. khawi tested positive for several pathogens, such as Leishmania spp., Trypanosoma spp., Bartonella spp. and orbivirus. Besides, S. khawi has been shown to exhibit human-biting behaviour through the analysis of blood meal. These findings raise concerns about its potential role in pathogen transmission, especially concerning zoonotic pathogens. However, vector competence remains unproven for some of these pathogens, suggesting the need for further research.

Recently introduced parasites are predicted to cause more severe infections because of a lack of host-parasite co-evolution. When new parasites co-occur with similar parasites they may compete for resources within a host, with mixed species infections potentially resulting in antagonistic, synergistic or additive effects. We tested Ostrea chilensis flat oysters in New Zealand for infections by two species of haplosporidian oyster parasites. Bonamia exitiosa is an endemic parasite to New Zealand, whereas Bonamia ostreae is an introduced species first detected in New Zealand in 2015. We investigated the infection intensity of each parasite by estimating gene copy numbers using species-specific digital droplet PCR (ddPCR) across Bonamia spp. allopatric and sympatric ranges. Our results showed that B. ostreae had significantly higher gene copy numbers than B. exitiosa. However, concurrent infections of both Bonamia parasites had similar intensities (based on gene copy number) to single-species infections, with no detectable interactive effects. Collectively, the results indicate that B. ostreae remains a significant risk to O. chilensis, although coinfections may not exacerbate disease. This study demonstrates the value of ddPCR screening and the importance of considering evolutionary ecology in the management of commercially important marine diseases.

Parasitic nematodes within Onchocercidae are a diverse group transmitted by hematophagous arthropods. This study investigated the molecular occurrence of filarioid nematodes in 93 wild mammals from the Amazon, Cerrado and Pantanal biomes in Brazil, based on the analysis of the mitochondrial genes 12S ribosomal DNA gene (12S rDNA) and cytochrome c oxidase subunit I gene (COI). Conventional polymerase chain reaction (cPCR) targeting the 12S rDNA gene yielded positive results in 14·44% (13/93) of the samples, including 9·86% of jaguars (7/71), 50% of pumas (1/2), 12·5% of giant anteaters (1/8), 50% of ocelots (1/2) and 60% of crab-eating foxes (3/5). Among the 12S-positive samples, 46% (6/13) also tested positive for the COI gene; however, only 1 sequence was suitable for further analysis. Phylogenetic analyses based on 12S gene sequences revealed 4 distinct lineages within the family Onchocercidae. Groups Ia and Ib, composed of Cerrado and Pantanal sequences from jaguars, formed sister clades to Brugia pahangi and Malayfilaria sofiani, respectively. The sequence from the giant anteater (Group Ic) was more divergent, forming a sister clade to species of the genera Malayfilaria, Wuchereria, and Brugia. Group II included sequences closely related to Dirofilaria immitis and D. striata, encompassing samples from crab-eating foxes, ocelots and a puma. These findings suggest that several wild mammal species may serve as reservoirs for previously uncharacterized Onchocercidae nematodes. Our findings expand the existing knowledge on host associations of filarioid nematodes infecting wild mammals from the Pantanal, the Cerrado and the Amazon Rainforest.

Intensive rearing of farmed fish may risk disease spillover into free-living populations. This study concerns the blood-feeding gill monogenean of salmonids, Discocotyle sagitatta, on the Isle of Man, UK. Heavy infections in 2 fish farms have led to severe disease with periodic mass mortality. Infection levels in rainbow trout (Oncorhynchus mykiss, overall n = 556) increased with age (i.e. years exposed): by year 3, prevalence was 100%, mean intensity c. 100 (maximum 1150) worms/host. Output from farms of many millions of parasite eggs/day has the potential for transmission to downstream populations of free-living trout. Infections of Discocotyle sagittata were recorded in 132 brown trout and 49 sea trout (Salmo trutta) at 9 sites in rivers associated with or independent of the farms. Its occurrence in all 5 rivers studied confirmed that it is endemic on the Isle of Man irrespective of the farms. Wild brown and sea trout in rivers local to the farms (Rivers Corrany and Neb) had similar burdens to fish from independent drainage systems (Rivers Laxey, Santon and Sulby), and all burdens were within the range reported for other free-living populations in the distribution of D. sagittata. Low worm burdens in brown trout persisted even where these occurred in farm ponds contiguous with heavily infected rainbow trout. It had seemed predictable that high worm burdens in the farms would increase infection in downstream wild fish, but no elevation was detectable. Instead, this and other studies indicate that brown trout develop protective immunity despite intensive re-infection from rainbow trout, preventing pathogenic disease.

Coccidia (Apicomplexa) may have a devastating effect on captive reptiles, particularly chameleons and bearded dragons (Pogona vitticeps). This study investigated the potential of three common feeder insects – the Argentine cockroach (Blaptica dubia), the banana cricket (Gryllus assimilis) and the superworm larva (Zophobas morio) – to act as passive vectors for coccidian oocysts, specifically Isospora amphiboluri and Choleoeimeria pogonae, common enteric parasites of captive bearded dragons. Faecal samples from experimentally infected bearded dragons were fed to the insects to assess the passage of viable oocysts through their digestive tracts. Gryllus assimilis exhibited the highest passage rates for both coccidia, followed by B. dubia; Z. morio showed the lowest rates. However, only G. assimilis passed both I. amphiboluri and C. pogonae at a significantly higher rate than Z. morio. These findings suggest that feeder insects, particularly crickets, can act as mechanical vectors for coccidia, highlighting the importance of strict hygiene protocols in reptile keeping minimizing the risk of parasite transmission.

Trypanosoma (Megatrypanum) pestanai is a parasite of the Eurasian badger (Meles meles), reported in various European countries. However, its presence in the Iberian Peninsula had not been previously investigated. To address this knowledge gap and to assess its occurrence and potential risk factors associated with infection, we analyzed DNA from the spleens of 145 badgers sampled across 4 autonomous regions in northern Spain. Two real-time PCR assays using a reference 18S rRNA partial sequence of T. pestanai (92 bp) were developed: one based on SYBR Green chemistry and the other employing a TaqMan probe. Both protocols demonstrated excellent concordance. Defining a sample as positive when at least 1 assay yielded a positive result, the overall prevalence was 35%, consistent with values previously reported in other European populations. A logistic regression model indicated a significantly higher occurrence in badgers from the Eurosiberian bioregion (42%) compared to those from the Mediterranean bioregion (19%). No significant associations were found with age or sex. A subset of positive samples was further analyzed by conventional PCR targeting approximately 900 bp of the 18S rRNA gene and sequenced. All 9 high-quality sequences shared 99.75–100% identity with known T. pestanai sequences. These findings confirm that T. pestanai is a common parasite of Iberian badgers and suggest that more humid climatic conditions may favour its persistence, potentially through effects on host ecology or vector dynamics.

Giardiasis is the most common enteric protozoan infection notifiable in New South Wales (NSW), Australia. Surveillance by NSW Health had shown a steady increase (prior to the COVID-19 pandemic) in the number of cases reported since 2012 and the reasons for this currently remain unknown. This study aimed to investigate the occurrence of Giardia intestinalis assemblages causing human infection in NSW. Individual faecal specimens were collected from participating hospitals and private laboratories, and the presence of Giardia and co-infections was confirmed by real-time multiplex-polymerase chain reaction (PCR). Samples were genotyped by sequence analysis of the triose phosphate isomerase (tpi) gene and the small subunit rDNA. Combined genotyping showed that most samples belong to assemblage B, and only a small percentage were infected with only assemblage A. Mixtures of assemblages A and B in individuals were relatively common. Co-infections were observed in ∼ half of the cases, with the most common co-infection being Blastocystis hominis and Dientamoeba fragilis. Although giardiasis was more prevalent in males, the assemblage distribution between the sexes appeared uniform. The age distribution was bimodal, with peaks in 0–15-year-olds and in adults in their 30s. The overall largest number of cases was collected from patients aged 30–49 years. Interestingly, females aged 5 years old and under had a greater risk of assemblage B infection than their male counterparts. No significant correlation was found between assemblage and clinical symptoms. This study provides new insights into the molecular diversity of giardiasis in NSW and helps inform enhanced surveillance and prevention strategies in Sydney.

While the interaction between humans and their parasites is well studied today, taking a long view of infection throughout human evolution helps to place the current picture in context and identify trends in infection over time. After considering how early technologies may have facilitated the transmission of parasites to humans, we examine the association between humans and parasites through time using archaeological and genetic evidence. Techniques such as microscopy, immunoenzymatic assays and DNA analysis have identified a range of protozoa, helminths and ectoparasites in our ancestors. Evidence is discussed for the origins and impact upon societies through time for protozoa causing malaria, leishmaniasis, Chagas’ Disease and diarrhoeal illnesses, helminths such as schistosomiasis, soil-transmitted helminths, Taenia tapeworms, fish tapeworms and liver flukes, and ectoparasites such as fleas, body lice and pubic lice. Prevalence studies show widespread infection for some parasites, such as 36% with falciparum malaria in ancient Egypt, and 40% with Chagas disease in prehistoric Peru and northern Chile. Humans have been responsible for the inadvertent spread of a range of parasites around the world, ranging from African heirloom parasites with early human migrations to the introduction of malaria and schistosomiasis to the Americas with the transatlantic slave trade in the 1600s–1800s. It is clear that the epidemics due to bacterial pathogens spread by ectoparasites since the Bronze Age must have had major impacts upon past societies, particularly for bubonic plague and epidemic typhus.

A new genus and species of trematode, Paratestophis gelicolus gen. nov., sp. nov., is described from the large intestine of the rainbow water snake, Enhydris enhydris, collected from several provinces in southern Thailand. Morphological analyses reveal distinct characteristics that differentiate P. gelicolus gen. nov., sp. nov. from related echinochasmid taxa, specifically its elongated bottle-shaped body, presence of 22 collar spines, parallel testes and parasitism of snakes–features not observed in other echinochasmid genera. Multi-marker phylogenetic analyses (28S rRNA, 18S rRNA, ITS2 and COI) strongly support its taxonomic placement within Echinochasmidae while confirming its genetic distinction from known genera such as Echinochasmus, Stephanoprora, and Microparyphium, thereby warranting the establishment of Paratestophis gen. nov. The species exhibited a 24% prevalence of infection (25/106) in E. enhydris, and was found co-infecting with four other helminths, including Tanqua siamensis, Encyclometra bungara, and two additional trematode species currently under examination, all occupy distinct ecological niches. Principal Component Analysis based on 19 morphological characters revealed morphological homogeneity among the specimens. This study represents the first record of a new genus and species within Echinochasmidae infecting snakes, and provides an updated systematic framework for the family, including a revised key to genera. The findings emphasise the need for further research into parasite taxonomy, host specificity and evolutionary relationships in Southeast Asian ecosystems.