Parasite Larvae Research Articles

In vitro culture of the parasitic stage larvae of hematophagous parasitic nematode Haemonchus contortus.

Current research on common parasitic nematodes is limited because their infective stages cannot be propagated in vitro. Here, we report a culture system for developing L4s of Haemonchus contortus, a blood-feeding nematode of ruminants. Our results demonstrated that a proportionate mixture of NCTC-109 to Luria-Bertini (1:2) media promoted the formation of early L4s and then into late L4s upon inclusion of 12.5% (v/v) defibrinated blood, albeit with a decline in survival. Adding antioxidants (0.3 mg/mL of L-glutathione or 200 nmol of vitamin C) improved survival of L4s, with approximately 90% developing to late L4s by 22 days. These L4s showed parallel morphological features (such as digestive and reproduction systems) compared with in vivo L4s at day 7 (following challenge infection), although with delayed development. Our work optimized the in vitro culture system for L4s while providing an important platform for in-depth molecular research on Haemonchus and other related parasitic nematodes.

Larval development and parasitism of emerald ash borer (Agrilus planipennis) in Oregon ash (Fraxinus latifolia) and European olive (Olea europaea): implications for the West Coast invasion.

The invasive emerald ash borer (Agrilus planipennis Fairmaire) (EAB) has been devastating North American ash (Fraxinus spp.) resources for over 2 decades. In its native range, EAB attacks and kills primarily stressed ashtrees. In North America, however,EABalsoattacks healthy trees of every Fraxinus species encountered, most recently Oregon ash (Fraxinus latifolia Benth.). Successful EAB development has also been reported in European olive (Olea europaea L.). The recent detection of EAB in Oregon puts the future of these 2 hosts into question, as little is known about EAB's development in these species or how introduced biocontrol agents will respond. We conducted laboratory and field infestations of olive and ash in Delaware and Oregon to assess EAB development and associated parasitoid responses. We found no difference in the net population growth rate of EAB developing in Oregon ash versus green ash. However, these species supported significantly more population growth than olive, in which EAB net population growth rate was zero, with most larvae dying prematurely. Artificially infested olives were small, which may have negatively impacted phloem availability and larval survival. Future studies should be conducted investigating EAB development on larger olive material. Although no parasitism was observed in infested olive, as EAB larvae seldom reached life stages (third or fourth instars) susceptible to larval parasitism, late-instar larvae developing in Oregon ash were attacked by both Tetrastichus planipennisi Yang and Spathius galinae Belokobylskij and Strazanac, suggesting that biocontrol is a suitable option for this newly invaded region.

Parasites in Sewage: Legal Requirements and Diagnostic Tools.

Despite the vast amount of water on Earth, only a small percent is suitable for consumption, and these resources are diminishing. Moreover, water resources are unevenly distributed, leading to significant disparities in access to drinking water between countries and populations. Increasing consumption and the expanding human population necessitate the development of novel wastewater treatment technologies and the use of water treatment byproducts in other areas, such as fertilisers. However, water treatment sludge often cannot be used to enhance crop production due to the presence of parasite eggs, particularly from roundworms (Ascaridae family), which are resistant to environmental factors and can pose a threat for several years. Legislation prohibits the use of sludge containing parasite eggs as fertiliser. In some cases, water may not contain parasite eggs but larvae, which require different detection methods. Additionally, the presence of eggs does not necessarily indicate danger since they may lose infectivity due to prolonged storage or exposure to chemical compounds in the sewage. This paper reviews European Union regulations on wastewater treatment, the selected parasitic diseases related to the presence of parasites in wastewater, the spectrum of detection methods, and highlights differences in viability and invasiveness, which is intended to draw attention to the need to determine both biological properties of parasites.

Intestinal Parasites Isolated from Some Vegetables Sold in Ado-Ekiti Market, Ekiti State, Nigeria

Objective: There is a reported association between contaminated fresh vegetables and food-borne parasitic diseases. Intestinal parasite infections are a global public health threat. Methodology: A cross-sectional study was conducted between May and June 2023 to identify parasites in common vegetables from markets in Ado-Ekiti, Ekiti State, Nigeria. A total of 120 vegetable samples from four markets were examined. The vegetables were washed separately in 150 ml of normal saline to remove parasitic ova, larvae, or cysts. After discarding the vegetables, the residue was left overnight, sieved, and the suspension was centrifuged at 2,000 rpm for five minutes. The sediment was examined under a light microscope using ×10 and ×40 objectives. Results: Out of the 120 samples examined, 78 (65%) of the vegetables were positive for intestinal parasites with which Ewedu leaf (Corchorus olitorius) recorded the highest parasitic contamination with 30 (38.5%). In contrast, Uziza leaf (Piper guineense) and Carrot (Daucus carota) recorded the lowest parasite contamination 4 (5.1%). Seven different types of parasites were isolated from 120 vegetables from 4 different markets; these parasites include Strongyloides stercoralis 34 (43.6%), Gardia lamblia 20 (25.6%), Ascaris lumbricoides 8 (10.3%), Hookworm 6 (7.7%), Entamoeba histolytica 4 (5.1%), Balantidium coli 4 (5.1%) and Trichuris trichuria 2 (2.6%). Conclusion: Vegetables from selected markets in Ado-Ekiti were contaminated with significant parasites, posing disease transmission risks. Enhanced hygiene practices among farmers, consumers, and vendors are crucial to reducing intestinal parasite infections.

Mixed strongyle parasite infections vary across host age and space in a population of feral horses.

Identifying factors that drive among-individual variation in mixed parasitic infections is fundamental to understanding the ecology and evolution of host–parasite interactions. However, a lack of non-invasive diagnostic tools to quantify mixed infections has restricted their investigation for host populations in the wild. This study applied DNA metabarcoding on parasite larvae cultured from faecal samples to characterize mixed strongyle infections of 320 feral horses on Sable Island, Nova Scotia, Canada, in 2014 to test for the influence of host (age, sex and reproductive/social status) and environmental (location, local density and social group membership) factors on variation. Twenty-five strongyle species were identified, with individual infections ranging from 3 to 18 species with a mean richness (±1 s.d.) of 10.8 ± 3.1. Strongyle eggs shed in faeces were dominated by small strongyle (cyathostomins) species in young individuals, transitioning to large strongyles (Strongylus spp.) in adults. Egg counts were highest in young individuals and in the west or centre of the island for most species. Individuals in the same social group had similar parasite communities, supporting the hypothesis that shared environment may drive parasite assemblages. Other factors such as local horse density, sex, date and reproductive/social status had minimal impacts on infection patterns. This study demonstrates that mixed infections can be dynamic across host ontogeny and space and emphasizes the need to consider species-specific infection patterns when investigating mixed infections.

How do trematode clones differ by fitness-related traits and interact within a host?

Polyclonal infections are widespread and provide evidence of facilitation, competition, and neutral interactions between parasite clones, even within the same host–parasite system. The outcome of coinfections is usually assessed by means of parasite infection intensities, while other important fitness-related traits, e.g., larval growth rates, are often ignored. We experimentally infected fish (Salvelinus malma) with different clones of the common trematode Diplostomum pseudospathaceum and pairs of clones. Clones were identified by microsatellite analysis. Their infectivity and growth rates within the fish were investigated in double-clone infections compared with single-clone ones. In total, 3838 parasite larvae (metacercariae) from 325 fish were measured. The growth rates of the D. pseudospathaceum clones were more variable than their infectivity. Relationships of these parasite traits with host mass were clone-specific. Some clones demonstrated higher infection intensities and growth rates in larger fish. Therefore, specialization toward different size groups of fish hosts may occur in this parasite species. Furthermore, we noticed a positive correlation between population density and parasite growth (Allee effect; rarely reported for parasites) but only in mixed infections. In double-clone infections, evidence of both interclonal facilitation and interclonal competition was found. When clones interacted, they either “cooperated” during infection of the host or competed while growing. There were no clone pairs in which interactions changed in type with time or were present constantly during development of the parasite.

Molecular methods for the detection and identification of parasitoids within larval wheat midges

Three species of cecidomyiid midges (Diptera: Cecidomyiidae) cause significant yield losses on wheat in Europe: Sitodiplosis mosellana (Géhin), Contarinia tritici (Kirby) and Haplodiplosis marginata (von Roser). Eggs and young larvae may be parasitised by a complex of hymenopteran parasitoids belonging to the Pteromalidae and Platygastridae families which contributes to natural pest control. We have developed molecular tools for detecting and identifying seven parasitoid species previously encountered in Belgium inside individual wheat midge larvae. Barcode DNA sequences from COI, 18S and 28S genes were obtained from the midges and parasitoid species. Each of the three genes allowed all the species to be distinguished although 18S was the only one displaying a barcoding gap, both between parasitoids and midges, and at the species level. Based on the 18S gene, we developed a TaqMan assay to assess parasitism in midge larvae, regardless of the midge and parasitoid species. Next, two group-specific PCR primer pairs were generated, allowing the separate amplification of midge DNA or parasitoid DNA in parasitised individuals and subsequent identification by Sanger sequencing. Finally, species-specific primers were designed to identify six parasitoid species by simple PCR amplification. These tools were successfully applied to assess the parasitism rate of S. mosellana larvae in seven Belgian fields.

First record of water mite larvae, Hydrachna sp. (Acari, Hydrachnidae) parasitism as quiescent nymphophan on two major aquatic insects of Coleoptera and Hemiptera from West Bengal and Odisha, India

Occurrence of quiescent nymphophan of Hydrachna sp. attaching to the sternites and tergites of thorax and abdomen of water beetle (Hydrophilus sp.) and giant water bug (Lethocerus sp.) is reported for the first time from West Bengal and Odisha of India. After feeding from one to five weeks as a parasitic larva on its host, Hydrachna sp., stops feeding and enters a quiescent nymphophan (nymphochrysalid) stage of development in which the larva squeezes into its exoskeleton and forms a sac-like structure where metamorphosis occurs. By the means of gnathoma, it remains attached to the host body casts off its exoskeleton, and within a short time, the developing nymph can be seen within it. The nymph comes out of a slit in the exoskeleton and assumes a free-living existence. These nymphochrysalids ranged in length from 682.17 to 2112.45?m with lateral stripes adorning their external integuments. Body appeared to be bottle shaped with pointed or rounded posterior end. Preferences of water mites for insect host body parts and seasons, infection intensity and prevalence were reported.

Genetic variation and population structure of Taenia multiceps (Coenurus cerebralis) based on mitochondrial cox1 gene: A comprehensive global analysis

Taenia multiceps is a neglected parasite having veterinary and public health importance. The predilection sites of the parasite larva (Coenurus cerebralis) are brain (cerebral coenurosis) and subcutaneous (non-cerebral coenurosis). There is a dearth of data regarding molecular characterization of T. multiceps and even fewer population structure-based studies on T. multiceps. The current study was conducted to provide epidemiological information regarding the global population structure of the parasite. The NCBI GenBank database was accessed to download the sequences of cox1 gene, which were further subjected to PopArt software to construct median-joining networks. The DnaSp software was used to compute neutrality and diversity indices. Host and region-wise indices of neutrality and diversity were also computed. There were 166 gene sequences found in the NCBI database. Followed by removal of short gene sequences, 143 were considered to perform bioinformatic analyses. A total of 30 haplotypes with 46 mutations and 23 parsimony informative sites were found. High diversity (Hd = 0.889, π = 0.01186) and negative but statistically insignificant neutrality indices (Tajima's D = −1.57659, Fu's Fs = −10.552) were found. Region-wise results revealed highest haplotype diversities in isolates from KSA (Hd = 1.00) followed by Greece and Italy (Hd = 0.962), and China (Hd = 0.931). Host-wise data analysis showed an overall negative Tajima's D value and there exists highest haplotype diversity in cattle (Hd = 1.00) followed by dogs (Hd = 0.833), sheep (Hd = 0.795) and goats (Hd = 0.788). The findings of the study indicate that the population diversity of T. multiceps will increase worldwide as shown by high diversity and negative neutrality indices. The findings of the study significantly add-in to the existing bank of knowledge about population structure of T. multiceps. We recommend conducting more studies employing different genetic markers to better comprehend the epidemiology of the parasite.

Deciphering Chemical Rules for Drug Penetration into Strongyloides.

Background: Strongyloidiasis, a parasitic infection, presents a significant public health challenge in tropical regions due to the limited repertoire of effective treatments. The screening of chemical libraries against the therapeutically relevant third-stage larvae (L3) of the model parasite Strongyloides venezuelensis yielded meager success rates. This situation is reminiscent of Gram-negative bacteria, where drug entry is a limiting factor. Methods: Here, we set out to determine whether similar barriers are in place and establish whether structural and property requirements exist for anti-strongyloides drug discovery. We focused on dyes as their uptake and effects on viability can be independently assessed in the multicellular parasite, thus providing a means to study the possibility of similar entry rules. We tested different dyes in in vitro assays on L3s. Results: We found that staining was necessary to reduce parasite viability, with some dyes achieving anti-strongyloides effects at concentrations similar to those of the reference drug, ivermectin (IV). Some dyes also showed activity against female adults at concentrations well below that of ivermectin. Unfortunately, the most potent dye, Methylene Blue, was unable to prevent the infection in a preliminary in vivo mouse model assay, presumably due to fast dye clearance. Structural analysis showed that positive charges facilitated the access of the compounds to the L3 tissue, thus providing a structural tool for the introduction of activity. For female adults, low globularity is additionally required. As a proof of concept, we added a positive charge to an inactive compound of one of our chemical libraries and re-determined the activity. Conclusions: These findings allow us to establish structural rules for parasite entry that could be of interest for future drug screening or drug development campaigns. These rules might also be applicable to other related parasites.

Reciprocal transplant experiments demonstrate a dynamic coevolutionary relationship between parasitic mussel larvae and bitterling fishes

Abstract The coevolutionary dynamic of host–parasite associations varies from strictly local adaptations to diffuse guild coevolution. How innate and acquired immune responses modulate host resistance to parasitism and how host specificity and geographic scaling affect the efficacy of host response have consequences for range dynamics and biological invasions. Using reciprocal transplant experiments, we tested whether local or diffuse coevolution shapes host response to parasitism in the host–parasite association between bitterling fishes and larval stages (glochidia) of freshwater mussels from Europe and East Asia. We found that glochidia initially indiscriminately attached to all study host species, but immune responses elicited significant differences in host responses within 24 h of infection, which intensified during glochidial development. European bitterlings were more resistant to European glochidia and Asian bitterlings to Asian glochidia, with the strongest geographic bias in resistance in the Asian bitterling hosts. This finding suggests a strong effect of local adaptation but also indicates the non‐negligible role of coevolutionary hotspots. Low natural glochidia load on bitterling species overall hence arise from competent immune response rather than glochidia avoidance behaviour. Bitterling immune response is primarily innate and not acquired. Overall, our data demonstrate the complex outcome of parasite pressure on the evolution of host resistance, and important role of geographically structured coevolution in shaping host response.

Papaya Seed Extract Combined Lauryl Glucoside Against Human Parasites Contaminated in Fresh Vegetables

Background: The prevalence of parasites in Thailand, primarily transmitted through contaminated vegetables, poses a significant public health concern. Ensuring the safety of natural produce from both parasites and chemical residues necessitates robust sanitation measures. Objective: This study aims to develop effective vegetable-washing solutions using papaya seed extract with potent anti-parasitic properties contamination in fresh vegetables. Methods: Fresh vegetables contaminated with Strongyloides stercoralis larvae, Ascaris lumbricoides, and Taenia spp. eggs were subjected to various treatments: distilled water, tap water, vinegar (5%), papaya seeds extract (200 mg/L), lauryl glucoside (1%) from coconut oil, papaya seeds extract combined with lauryl glucoside, and Albendazole as a standard drug. Immersion for 5 minutes was followed by parasite observation using the sedimentation method over 60 minutes, examining inhibitory effects on parasite larvae movement. Results: Papaya seed extract achieved the most rapid cessation within 10 minutes for larvae movement, followed by vinegar and papaya seed extract combined with lauryl glucoside. Furthermore, papaya seed extract combined with lauryl glucoside exhibited the highest efficacy in the sedimentation larval and parasite eggs, followed by lauryl glucoside solution and papaya seed extract, surpassing the control group. Conclusion: Papaya seeds extract immobilized larvae, while lauryl glucoside effectively eliminated parasite eggs from vegetables. Natural and organic compounds derived from papaya and coconut oil exhibit inherent diversification in their properties. These compounds originate from natural sources, showcasing distinct characteristics attributed to their organic nature. These results indicate the potential for developing natural extract-based products as future vegetable-washing solutions, emphasizing their significance against parasitic efficacy.

Increasing the Growth of Bridal Tears Flower Stem Cuttings (Antigonon leptopus) by providing Plant Growth Regulators and Planting Media

It is imperative to implement integrated control measures for Oil Palm Leaf-Eating Caterpillars (UPDKS), as continual chemical management can result in pest resistance and environmental degradation. Utilizing natural enemies for biological control involves the utilization of predators, pest-consuming animals, as well as parasites or bacteria with pathogenic properties against pests. Examples of predators, including Sycanus leucomesus and Eocanthecona furcellata, egg parasitoids, such as Trichogrammatidea thoseae, and larval parasites, such as Chaetexorista javana, are a few of the many types of organisms that can have an impact on the populations of their prey. These indigenous predators sustain themselves by feeding on host plants within their natural habitat. The bridal tears flower (Antigonon leptopus) is considered to be one of the host plants. Thus, it is imperative to promote the growth of Antigonon leptopus in order to provide a habitat for the natural predators of the UPDKS pest. The objective of this research was to identify the components of the planting medium and to establish the most effective concentration of growth regulators for propagating bridal tears stem cuttings (Antigonon leptopus). The research was conducted at the Indonesian Palm Oil Technology Institute (ITSI) Practice Garden in Medan, North Sumatra. The research was conducted over three months, from February to April 2024. The Factorial Randomized Block Design (RAK) method was employed, with the first factor, namely S (Planting Media), comprising three levels: Top Soil without solid, Top Soil with 20% Solid, and Top Soil with 40% Solid. The second factor, namely Plant Growth Regulators, was also treated with three levels: without plant growth regulators, concentration of 100 Mg/l, and concentration of 200 Mg/l. Thus, the study comprises nine treatment combinations, each with four replications. The analysis of variance (ANOVA) table is employed to assess the significance of the observed differences, with the Duncan multiple range test (DMRT) conducted at a 5% level of significance when warranted.The findings from the research indicated that the manipulation of the planting medium composition (S) had a notable impact on the number of leaves, number of roots, and fresh weight of the roots. Additionally, it was found to have a highly significant influence on the height of the shoots. The optimal composition of the planting medium was identified as S2. The manipulation of growth regulators (R) concentration had a notable impact on shoot height and root fresh weight, as well as a highly significant effect on the number of leaves and roots. R2 exhibited the most optimal concentration of growth regulators. The growth of Antigonon leptopus stem cuttings was not affected by the combination of planting medium composition (S) and growth regulator concentration (R) in a non-interacting manner.

Sensing atmospheric pressure could protect parasitic larvae from incoming storms

Sensing atmospheric pressure could protect parasitic larvae from incoming storms

Effect of insecticides and intercropping systems on fall armyworm (Spodoptera frugiperda (J.E. Smith)) infestations and damage in maize in northern Ghana

Field studies were conducted over two successive seasons to test the effects of maize-legume intercropping system on fall armyworm (FAW) (Spodoptera frugiperda (J.E. Smith)) and if insecticide use was necessary in intercropping systems. Three insecticide treatments [no spray, Emastar 112 EC (a.i. emamectin benzoate 48 g/L + acetamiprid 64 g/L), Neem seed oil (NSO) (a.i. 3% azadirachtin)] and three intercropping systems [sole maize (Zea mays L.), maize + soybean (Glycine max (L.) Merr.) and maize + groundnut (Arachis hypogaea L.)] were arranged as a 3 × 3 factorial experiment in a randomized complete block design. Data were collected on FAW larval infestations, parasitism rates, damage, grain yield and gross financial returns. Results from combined-years analyses showed that larval infestation was significantly affected by intercropping (p = 0.034) only, with maize + soybean recording the lowest infestation while sole maize was highest. Damage to crop and cobs were significantly affected by years and insecticide treatments. Cob damage was also significantly affected by intercropping system with maize + soybean being lowest and sole maize recording the highest damage. Parasitoids recorded were Coccygidium luteum, Chelonus bifoveolatus, and Charops sp. Grain yield was significantly affected by the intercropping systems only (p = 0.004), with no significant year (p = 0.152), insecticide (p = 0.726) and insecticide × intercropping system (p = 0.660) effects. Sole maize (1.6 t/ha) had the lowest yield while maize + groundnut (2.2 t/ha) was highest. In terms of income, an economic analysis showed that spraying intercropped maize with NSO resulted in the highest marginal rate of return. Thus, the use of NSO and intercropping is an effective FAW management strategy.

Local factors have a greater influence on the abundance of alfalfa weevil and its larval parasitoids than landscape complexity in heterogeneous landscapes

ContextThe alfalfa weevil Hypera postica Gyllenhal (Coleoptera: Curculionidae) is one of the most destructive pests of alfalfa worldwide. Both local and landscape-scale factors can significantly influence crop pests, natural enemies, and the effectiveness of biological control services, but the relative influence of these factors is unclear.ObjectivesWe investigated the influence of the local variables and surrounding landscape composition and configuration on the abundance of alfalfa weevil, and on the abundance and parasitism rates of its larval parasitoids, Bathyplectes spp.MethodsWe sampled 65 commercial alfalfa fields along the Ebro Basin, Spain, over a period of 3 years, recording the field characteristics and landscape structure at three buffer radii of 250, 500 and 1000 m from the center of each field.ResultsThe abundance of weevil larvae was positively associated with the field perimeter and with the uncut alfalfa surrounding the pipes of the sprinkler irrigation system, but only one configuration variable was positively correlated: the alfalfa edge density. No local characteristics or landscape structures were associated with the abundance of adult weevils. The abundance of Bathyplectes spp. adults was positively associated to local factors such as the densities of alfalfa weevils and aphids. Few landscape structure variables, such as alfalfa edge density and Simpson’s Diversity Index, had explanatory value only at 250 m buffer radius. The rate of larval parasitism was affected by local variables, such as alfalfa weevil abundance and field age.ConclusionOur results provide, for the first time in the Mediterranean region and Europe, evidence of the relative importance of landscape structure and local factors on the abundance of the alfalfa weevil and its larval parasitoids, Bathyplectes spp. The strongest influences were based on local characteristics.

Nematomorpha - poorly known parasites of invertebrates

Nematomorpha, also known as ‘horsehair worms’, is a poorly known group of animals that parasitize as larvae both, invertebrates and, less frequently vertebrates. There are approximately 360 species within this phylum, and previously, they were incorrectly classified as representatives of nematodes due to morphological similarity. Nematomorpha are cosmopolitan, found in fresh and salt water, and on land, usually in humid habitats. Their life cycles are simple or complex and usually associated with the phenomenon of ‘parasitic manipulation’ of the host. This term refers to parasites that can take control of their host's body and behaviour. These efforts mainly lead to the host's death in the name of parasites' survival. The level of knowledge about Nematomorpha is insufficient, as is the role of these behaviour-altering parasites in the ecosystem. This is mainly due to their relatively low species representativeness and a secretive lifestyle in which, alongside free-living adults, there are parasitic larvae. The aim of this article is a review of the literature on ‘horsehair worms’ and an attempt to determine further directions of research on this systematic group.

Parasites with zoonotic potential in dog feces and sand collected in public squares of Blumenau, Santa Catarina, Brazil

The presence of parasitized animals in streets, squares, parks, and other public places contributes to environmental contamination by infective forms of zoonotic parasites. Thus, this study aimed to evaluate the frequency of eggs, cysts, oocysts and/or larvae of parasites in samples of sand and feces present in nine public squares in the city of Blumenau, Santa Catarina, Brazil, through the four seasons of the year. Samples were collected between March 2021 and April 2022, totaling 223 dog feces samples and 106 sand samples. The dog feces samples were analyzed by the Willis method and by the Faust method, and the sand samples were analyzed by the Hoffman method and by the method of Flotation in Saturated Sodium Chloride Solution (NaCl). All analyzed squares had at least one positive sample. Of the 223 stool samples collected from March 2021 to April 2022, 31 (13.9%) were positive for at least one parasite. Of the registered positive samples, Ancylostoma spp. was the most frequent parasite, observed in 26 samples (57.8%); followed by Entamoeba sp., identified in 11 samples. As for the contamination of the sandboxes, of the 106 samples collected, 11 (10.37%) were positive for some parasite. These results highlight the importance of improving public spaces, and school educational campaigns highlighting the importance of hygiene and reducing contamination by infective parasites, thus contributing to improving public health in the city of Blumenau, SC. KEY WORDS: Zoonoses; sand contamination; hookworm; public spaces.

A comprehensive molecular phylogeny of the terrestrial Parasitengona (Acariformes, Prostigmata) provides insights into the evolution of their metamorphosis, invasion into aquatic habitats and classification

Parasitengona (velvet mites, chiggers and water mites) is a highly diverse and globally distributed mite lineage encompassing over 11,000 described species, inhabiting terrestrial, freshwater and marine habitats. Certain species, such as chiggers (Trombiculidae), have a great medical and veterinary importance as they feed on their vertebrate hosts and vector pathogens. Despite extensive previous research, the classification of Parasitengona is still contentious, particularly regarding the boundaries between superfamilies and families, exacerbated by the absence of a comprehensive phylogeny. The ontogeny of most Parasitengona is distinct by the presence of striking metamorphosis, with parasitic larvae being heteromorphic compared to the predatory free-living deutonymphs and adults. The enigmatic superfamily Allotanaupodoidea is an exception, with larvae and active post-larval stages being morphologically similar, suggesting that the absence of metamorphosis may be either an ancestral state or a secondary reversal. Furthermore, there is disagreement in the literature on whether Parasitengona had freshwater or terrestrial origin. Here, we inferred phylogenetic relationships of Parasitengona (89 species, 36 families) and 307 outgroups using five genes (7,838 nt aligned). This phylogeny suggests a terrestrial origin of Parasitengona and a secondary loss of metamorphosis in Allotanaoupodoidea. We recovered the superfamily Trombidioidea (Trombidioidea sensu lato) as a large, well-supported, higher-level clade including 10 sampled families. We propose a new classification for the terrestrial Parasitengona with three new major divisions (epifamilies) of the superfamily Trombidioidea: Trombelloidae (families Audyanidae, Trombellidae, Neotrombidiidae, Johnstonianidae, Chyzeriidae); Trombidioidae (Microtrombidiidae, Neothrombiidae, Achaemenothrombiidae, Trombidiidae, Podothrombiidae); and Trombiculoidae (=Trombiculidae sensu lato). Adding them to previously recognized superfamilies Allotanaupodoidea, Amphotrombioidea, Calyptostomatoidea, Erythraeoidea, Tanaupodoidae and Yurebilloidae.

Surveillance of parasitic infections in market-sold aquatic products and knowledge and practice towards food-borne parasitic diseases among residents in Shanghai Municipality from 2020 to 2023

To investigate the prevalence of parasitic infections in market-sold aquatic products in Shanghai Municipality, and to understand the knowledge and practice towards food-borne parasitic diseases among residents, so as to provide insights into the surveillance and control of food-borne parasitic diseases. Freshwater products, seawater products and pickled products were randomly obtained from agricultural trade markets, supermarkets, retail stores and restaurants in Huangpu, Putuo, Minhang and Qingpu districts of Shanghai Municipality from 2020 to 2023. Parasite metacercariae and larvae were detected in these aquatic products using pressing method, digestion method and the dissection method, and the detection of parasitic infection was compared in different types of aquatic products. In addition, the knowledge and practice towards food-borne parasitic diseases were investigated among residents aged 10-80 years old who randomly selected from agricultural trade markets, supermarkets, community streets and other population concentration areas in these four districts by questionnaire in 2023, and the awareness of food-borne parasitic diseases knowledge and percentage of healthy behaviors formation were analyzed. A total of 2 109 aquatic products sampled from Huangpu, Putuo, Minhang and Qingpu districts of Shanghai Municipality from 2020 to 2023 were detected, and there were 317 products detected with parasitic infections, with an overall detection rate of 15.03%. There were 8 products detected with parasitic infections in 1 221 freshwater products, with a detection rate of 0.66%, and Clonorchis sinensis was the predominant parasite, which was detected in Pseudorasbora parva, Rhodeus amarus and Carassius auratus. There were 82 products detected with parasitic infections in 501 seawater products, with a detection rate of 16.37%, and Anisakis was the predominant parasite, which was detected in Trichiurus lepturus, Larimichthys polyactis, Pneumatophorus japonicus, Collchthys lucidus, Mugil cephalus, Larimichthys crocea, Scomberomorus niphonius, Stromateoides argenteus and Cololabis saira. There were 227 products detected with parasitic infections in 387 pickled products, with a detection rate of 58.66%, and the prevalence rates of Echinostoma metacercariae were 76.27% (225/295) in Bullacta exarata and 11.11% (2/18) in crab pastes, respectively (χ2 = 159.511, P < 0.05). No Paragonimus infection was found in freshwater shrimps, crabs and pickled products, and no Diphyllobothrium latum larvae infection was detected in freshwater and seawater fish. Questionnaire surveys showed that the awareness of food-borne parasitic diseases knowledge was 79.00% (222/281), and the percentages of washing hands before and after meals, not drinking filtered water or tap water directly, not eating raw or semi-raw food, being willing to change special dietary preferences or bad living habits for health, and being willing to learn more about food-borne parasitic diseases knowledge were 99.64% (280/281), 72.24% (203/281), 56.23% (158/281), 96.80% (272/281) and 97.51%(274/281) among residents living in Huangpu, Putuo, Minhang and Qingpu districts, respectively. There are food-borne parasite contaminations in market-sold aquatic products in Shanghai Municipality. Although residents are aware of food-borne parasitic diseases knowledge, sustainable surveillance of food-borne parasitic diseases and improved health education are required to minimize the risk of human parasitic infections.