Definitive Hosts Research Articles

Global profiling of the proteome, phosphoproteome, and N-glycoproteome of protoscoleces and adult worms of Echinococcus granulosus.

Cystic echinococcosis (CE) is a chronic zoonosis caused by infection with the metacestode of the Echinococcus granulosus. A unique characteristic of E. granulosus protoscolex (PSC) is their ability to develop bidirectionally into an adult worm in the definitive host or a secondary hydatid cyst in the intermediate host. Furthermore, cestodes have a complex life cycle involving different developmental stages; however, the mechanisms underlying this development remain unknown. Several studies have demonstrated that certain matrix proteins undergo posttranslational modifications (PTMs), including phosphorylation and glycosylation, which have important regulatory effects on their functional properties. Systematic analyses of the proteome, phosphorylated modified proteome, and glycosylated modified proteome of protoscoleces (PSCs) and adult worms were performed using a proteomic strategy. Data are available via ProteomeXchange with identifier PXD043166. In total, 6,407 phosphorylation sites and 1757 proteins were quantified. Of these, 2032 phosphorylation sites and 770 proteins were upregulated, and 2,993 phosphorylation sites and 1,217 proteins were downregulated in adult worms compared to PSCs. A total of 612 N-glycosylation sites were identified in the 392 N-glycoproteins. Of these, 355 N-glycosylation sites and 212 N-glycoproteins were quantified. Of these, 90 N-glycosylation sites and 64 N-glycoproteins were upregulated, and 171 N-glycosylation sites and 126 N-glycoproteins were downregulated in adult worms compared to PSCs. GO enrichment analysis indicated that the differentially expressed phosphoproteins were mainly enriched in the regulation of oxidoreduction coenzyme metabolic processes, myelin sheath, and RNA helicase activity, whereas the differentially expressed N-glycoproteins were enriched in the cellular response to unfolded proteins, endoplasmic reticulum lumen, and nucleic acid binding. KEGG enrichment analysis indicated that the differently expressed phosphoproteins were mainly enriched in RNA transport, hypertrophic cardiomyopathy (HCM), glycolysis/gluconeogenesis, HIF-1 signaling pathway and pyruvate metabolism. Differentially expressed N-glycoproteins were enriched in the PI3K-Akt signaling pathway, ECM-receptor interactions, and protein processing in the endoplasmic reticulum. To our knowledge, this study is the first global phosphoproteomic and N-glycoproteomic analysis of E. granulosus, which provides valuable information on the expression characteristics of E. granulosus and provides a new perspective to elucidate the role of protein phosphorylation and N-glycosylation in the development of E. granulosus.

Dog screening as a novel complementary guinea worm disease control tool to mitigate persistence in Chad: A modeling study

A free-roaming dog population remains one of the major public health problems in many developing countries. In this study, we investigated the potential impact of owned roaming and stray dogs on the persistence and possible eradication of Guinea worm disease (GWD) in Chad. We developed and analysed a multi-host of Guinea worm; and considered dogs as the definitive hosts, and fish as the intermediate hosts. Currently, GWD cases in the human population are low; hence, we ignored the human population in this study. We derived the reproduction number and explored how it depends on different model parameters that define it. We calibrated the proposed model with data from literature and validated it with recently reported GWD monthly data for dog infection in Chad from 2019 to 2022. Results show that detection and tethering of infectious owned free-roaming dogs combined with culling of stray dogs are effective disease management strategies. Hence, attainment of certain threshold levels for these interventions could lead to disease eradication. Overall, the study revealed how different factors could be applied to effectively manage GWD transmission in the dog population. Findings from this study could be used to support decision-making in GWD control strategies.Mathematics Subject Classification (2010): 92B05, 93A30, 93C15.

Molecular Survey of Hepatozoon canis Infection in Domestic Dogs from Sardinia, Italy.

Tick-borne protozoans of the genus Hepatozoon have been associated with infections of domestic and wild animals over the world. The occurrence of these apicomplexan agents in Sardinia has been poorly explored so far. In this study, the occurrence of Hepatozoon spp. has been investigated in domestic dogs from nine cities of Sardinia, Italy. Blood samples from each dog were collected and tested molecularly for the presence of Hepatozoon and Babesia/Theileria DNAs. Out of fifty-one dogs, nine were positive for Hepatozoon species based on the molecular detection of the parasite in blood samples. The phylogenetic relationships of strains detected here were also established. The PCR for amplification of the 18S rRNA fragment gene of Babesia/Theileria spp. did not give amplicons in any of the analyzed samples. Our results report the first molecular confirmation of Hepatozoon canis in Sardinian pet dogs and contribute to better understand the presence of these protozoans on the island. This study highlights the importance of recognizing and predicting the risk levels for the canine population, thus increasing the development of specific control measures. Also, since the distribution of hepatozoonosis is closely related to that of the definitive tick host, Rhipicephalus sanguineus, more accurate studies on Rhipicephalus ticks will be needed due to increasing the epidemiological knowledge of Hepatozoon species on the island.

Detection of IgG antibodies against T. gondii and associated risk factors in domestic and stray cats in Lusaka, Zambia

Toxoplasma gondii (T. gondii) is a nearly ever-present organism that infects humans, wildlife, birds, and domestic and food animals. T. gondii has been reported in pigs, chickens, sheep, goats, and cattle (1). However, only members of the cat family (Felidae) are the definitive host and shed the environmentally resistant oocyst form of the organism in their faeces. Transmission to humans usually occurs by ingesting cysts in undercooked meat and exposure to soil water which is contaminated by oocysts (2). Feline infections are typically subclinical; congenitally infected kittens are the ones that are most likely to have clinical signs of infection, but previously clinically healthy adult cats may also be affected (3). Despite the disease’s significance in public health, very few studies have been done on T. gondii in Zambia. This study was a cross-sectional survey to investigate the seroprevalence and risk factors of Toxoplasmosis. A survey was carried out using a questionnaire that was distributed to cat owners who attended the veterinary clinics. The questionnaire had demographic data for the cats, questions related to the risk factors of Toxoplasmosis in cats, and practices surrounding the cat owners, like how they handle cat litter, whether their cat was indoor or outdoor, contact of the cat with other cats, and straying behaviour of their cat. A total of 178 blood samples were collected from both stray and domestic cats in this study. Of the 178 samples tested for T. gondii IgG antibodies, 88 were from domestic cats and 90 from stray cats. 30 out of 178 samples were positive for antibodies, indicating an overall seroprevalence of 16.85%. Of the 30 positive seropositive samples, 60% (18) came from domestic cats and 40% (12) from stray cats. The seroprevalence for domestic cats was found to be 20.4% and that of strays 13.3%. The two risk factors found to be associated with toxoplasma Seropositivity were sex (p=0.007, 95%, CI 0.071,0.976) and diet (p=0.038, 95%, CI 1.395,95.418) It was concluded that Toxoplasma gondii was widely spread in the study population. The presence of the antibodies indicated that at one point in their lives, these cats were actively infected and shedding oocysts in the environment, thereby posing a risk to humans and other species like sheep and chickens.

Parasitological and molecular identification of cestode Bothriocephalus scorpii sensu stricto in the new host Chelidonichthys lucerna (L. 1758) (Triglidae, Scorpaenoidei) from the North Sea

A specimen of female tub gurnard (Chelidonichthys lucerna) caught as bycatch in commercial saithe, Pollachius virens, fisheries near the Shetland Islands was identified as a new definitive host for the cestode Bothriocephalus scorpii (Bothriocephalidea) sensu stricto. It was also the first Cestoda species recorded in tub gurnard. However, as shown in our study, the identification of complex species such as Bothriocephalus scorpii based only on external characteristics had to be supplemented with molecular marker analysis to determine the taxonomic status of the specimen. Therefore, to successfully identify the parasite specimen, DNA was extracted from it, and a partial sequence of lsrDNA was amplified and the PCR product was subjected to 2 × 300 bp PE sequencing with 10,000× coverage on MiSeq. A BLAST search using the 346 bp sequence showed 100% similarity to the lsrDNA sequence of B. scorpii deposited in GenBank under accession number AF286942. Relatedness between the sequence of B. scorpii found in our study and the 20 most similar records from GenBank was identified using a phylogenetic tree constructed under maximum likelihood. Our study proves that next-generation sequencing of partial lsrDNA supplemented the morphological identification of the parasite specimen and can be applied in future parasitological studies.

Risk Factors and Urogenital Schistomiasis Prevalence among Primary School Children in Makurdi, Nigeria

Urogenital schistosomiasis in humans is an infection of public health importance caused by infection with Schistosoma heamatobium. The study investigated the risk factors and intensity of urogenital schistosomiasis among primary school pupils in Makurdi, Nigeria. Eight hundred (800) school pupils consisting of 200 per school, aged 5 – 20 years in Angwan Jukun, Angwan Reke, Agbo and Ijaha communities, respectively were enrolled for the study. Suitably designed questionnaire was used to document data on the demographics as well as relevant information of the participants. Urine samples were collected from consented participants between 10 am – 2 pm, into pre-labelled plastic sample bottles following aseptic techniques. The samples were subjected to standard parasitological techniques for determination and quantification of parasite in the zoology laboratory of Benue State University, Makurdi. Research data was subjected to chi square analysis to ascertain association of the research variables with schistosomiasis prevalence in the study area. The study filed an overall prevalence of 23.75% (190/800). Infection rates were significantly associated with age as age group 16-20 years had the highest prevalence (P<0.000). Males 25.42% (122/800) were slightly more infected than females 21.25% (68/800) (P>0.05). Water contact pattern of participants revealed a highly significant association with schistosomiasis prevalence (p<0.001)). Grazing activity 50% (1/2) displayed higher infection prevalence followed by > 1 activity 34.65% (79/228) while no infection was seen in snail hunters. The association between the presence and type of livestock sharing open water sources with the communities was statistically significant (P<0.05). Makurdi is endemic for urogenital schistosomiasis and related risk factors. The roles of other definitive hosts in ensuring continual disease transmission and possible zoonosis should be investigated

Foodborne illnesses caused by tissue parasitic protozoa

Zoonotic infections caused by Sarcocystis species, known as intestinal sarcocystosis, are an example of foodborne illnesses that occur due to the consumption of contaminated meat. Zoonotic Sarcocystis parasites, specifically those hosted in cattle and swine meat, have been reported as the sole causative agents of human intestinal sarcocystosis. The infection’s symptoms include nausea, diarrhea, vomiting, and abdominal pain. Talking about zoonotic parasites goes hand in hand with discussing the parasite life cycle, animals that act as natural intermediate hosts, and humans who act as the natural definitive host for the parasite. To safeguard cattle and swine meat consumers, the government of Rwanda, through the Rwanda Inspectorate, Competition, and Consumer Protection Authority (RICA), has banned the sale of meat that has not been refrigerated for at least 24 hours and reached a temperature between 2oC and 4oC before sale in order to prevent the transmission of zoonotic and transmissible diseases. Based on various literature reports, zoonotic sarcocyst viability remains intact in this range of temperatures for a period of 24 hours. Given that the prevalence of swine coccidia in Rwanda was reported to be 55.8%, Coccidia may not only include Sarcocystis species. The established rule may not be contributing to the prevention of zoonotic sarcocystis parasite infection but it is a preventive solution for many other zoonotic parasites and pathogens. Due to the lack of research reports on zoonotic sarcocystis in Rwanda, there is limited knowledge about these parasites in the country. This lack of information may explain why the prevention and control measures taken to address zoonotic pathogen infection do not adequately address the issue of zoonotic sarcocysts. Though the parasite infection was reported to be negligible, it may induce reduced human food availability in the food production system due to the ability of the disease to be transmitted from humans to cattle and pork. These later animals' meat is prestigiously served as human food in Rwanda.

Ecological and molecular associations between neotropical wild felids and Taenia (Cestoda: Taeniidae) in the Atlantic Forest: a new report for Taenia omissa.

Ecological associations between wild felids and parasites from the Taeniidae family are related to predator-prey interactions, where felids act as definitive hosts while their prey, herbivores and/or omnivores, act as intermediate hosts. In the Atlantic Forest, six neotropical felid species coexist in sympatry, but the ecological parasite-host interactions remain poorly studied. Taenia omissa is a tapeworm that parasitizes cougars (Puma concolor) as its only definitive host and their ungulate prey as intermediate hosts. The aim of this study was to identify tapeworms present in road-killed fauna using both molecular and morphological characteristics and their predator-prey relationship. Adult tapeworms found in a cougar, a jaguarundi (Herpailurus yagouaroundi), and two ocelots (Leopardus pardalis); and metacestodes found in a red brocket deer (Mazama americana) and a wild guinea pig (Cavia aperea) were analyzed. Through morphological analysis of rostellar hooks and molecular analysis of the mitochondrial genetic marker cox1, Taenia omissa adult individuals were identified in the cougar, and metacestodes in the red brocket deer, proving the existence of a full host-parasite life cycle in the Atlantic Forest region. This new report reveals the southernmost record of T. omissa and broadens its geographic distribution. In addition, isolates of the Taenia genus divergent from those described so far in molecular databases were reported and suggested a wild cycle that involves the jaguarundi and agouti (Dasyprocta asarae) as definitive and intermediate hosts, respectively. These results highlight the complexity of the tapeworm population in the region and the need to study it with both morphological and molecular approaches.

Helminth Fauna of Bats in the Rostov Region: Review. 1. Nematoda

Introduction. Bats (Chiroptera) are the least studied group of mammals in many regions of Russia. At the same time, the chiropterans are known to be one of the largest orders of Mammalia, which can act as hosts and carriers of various pathogenic fungi, bacteria and viruses. However, the parasitic fauna of this group of animals is poorly investigated. The study of bat-parasitizing worms has great practical importance, since bats, due to their ancient origin, are a very detached order. Endoparasites, including the chiropteran helminths, have not been previously studied in the Rostov region. According to the available data, the up-to-date research on the bat parasites in Russia has been carried out only in the Saratov region and in the Republic of Mordovia. The aim of this series of articles is to study the helminth species composition parasitizing in chiropterans in the Rostov region. In the first report we present the data on nematodes.Materials and Methods. The materials for the research were the articles from the open access literature databases: PubMed (pubmed.ncbi.nlm.nih.gov), Cyberleninka (cyberleninka.ru), GoogleScholar (https://scholar.google.com ), etc. The main method used was the analysis of the collected data.Results. The authors were the first to reveal that 27 nematode species from 14 genera, 8 families, 4 orders and 2 classes can be found in 15 bat species living in the Rostov region. The numerous Chromadorea class is represented by 21 species, 12 of which are found in Russia.Discussion and Conclusion. The results of the literature sources analysis showed that the largest number of nematode species parasitize in two chiropteran species living in the Rostov region: in the Daubenton's bat (15 species) and in the common noctule (14 species). Only one species has been recorded in the northern bat. Most nematode species parasitize specifically in bats and have a direct life cycle. (e.g., species of the genus Molinostrongylus). For some species, such as Pterygodermatites bovieri and Litomosa spp., the intermediate hosts are arthropods and the definitive hosts are various bat species. For three nematode species: Ascarops strongylina, Physocephalus sexalatus and Spirocerca lupi, bats are the paratenic hosts.

De novo transcriptome assembly of an Antarctic nematode for the study of thermal adaptation in marine parasites

Understanding the genomic underpinnings of thermal adaptation is a hot topic in eco-evolutionary studies of parasites. Marine heteroxenous parasites have complex life cycles encompassing a free-living larval stage, an ectothermic intermediate host and a homeothermic definitive host, thus representing compelling systems for the study of thermal adaptation. The Antarctic anisakid Contracaecum osculatum sp. D is a marine parasite able to survive and thrive both at very cold and warm temperatures within the environment and its hosts. Here, a de novo transcriptome of C. osculatum sp. D was generated for the first time, by performing RNA-Seq experiments on a set of individuals exposed to temperatures experienced by the nematode during its life cycle. The analysis generated 425,954,724 reads, which were assembled and then annotated. The high-quality assembly was validated, achieving over 88% mapping against the transcriptome. The transcriptome of this parasite will represent a valuable genomic resource for future studies aimed at disentangling the genomic architecture of thermal tolerance and metabolic pathways related to temperature stress.

Morphological and molecular phylogenetic characterization of Sarcocystis kani sp. nov. and other novel, closely related Sarcocystis spp. infecting small mammals and colubrid snakes in Asia

We investigated the morphology and phylogenetic relationships of novel and previously recognized Sarcocystis spp. infecting small mammals and colubrid snakes in Asia. The nuclear 18S rRNA and mitochondrial cox1 of Sarcocystis sp.1 from mangrove snakes (Boiga dendrophila) in Thailand and Sarcocystis sp.2 from a ricefield rat (Rattus argentiventer) in Sumatra were partially sequenced. Sporocysts of Sarcocystis sp.1 induced development of sarcocysts in experimentally infected rats, which showed a unique ultrastructure that was observed previously by S.P. Kan in rats from Malaysia; therefore, we describe this species as Sarcocystis kani sp. nov. Its integration into the 18S rRNA phylogeny of Sarcocystis spp. cycling between small mammals and colubrid snakes helped clarify relationships among the so-called S. zuoi-complex of molecularly cryptic species: Sarcocystis kani sp. nov., S. sp.2, S. attenuati, S. scandentiborneensis, and S. zuoi were all included in this clade. Tree topology was resolved into dichotomies congruent with the morphological disparities between the taxa. However, cox1 gene sequencing (including newly sequenced S. singaporensis and S. zamani) revealed that Sarcocystis kani, S. attenuati, and S. scandentiborneensis were identical suggesting a recent, common ancestry. To identify other distinctive features, lineage-specific molecular patterns within both genes were examined revealing that all 18S rRNA sequences of the S. zuoi – complex possess a unique, 7-nt long motif in helix 38 of domain V7 that was different in S. clethrionomyelaphis which branched off basally from the complex. Three-dimensional homology modelling of COX1 protein structure identified amino acid substitutions within the barcode area specific for the S. zuoi-complex and substantial divergence in structurally important amino acids between Sarcocystis species of snakes as definitive hosts and other lineages of the Sarcocystidae. We discuss the utility of selected genes for species delimitation of the Sarcocystis spp. under investigation, which probably evolved during recent radiations of their intermediate and definitive hosts.

The jaguar (Panthera onca) as a potential new host of Dracunculus sp.

Nematode species of the genus Dracunculus (Spirurida: Dracunculoidea) infect tissues and body cavities of reptiles, domestic and wild carnivores, and humans. The definitive hosts acquire the infection by ingesting intermediate (i.e., cyclopoid copepod) or paratenic (i.e., amphibians and fishes) hosts. Here we report the jaguar (Panthera onca) as a potential new host for Dracunculus sp. The nematode was collected from an ulcerated cutaneous nodule on the left anterior limb of a female jaguar in the municipality of Miranda, Mato Grosso do Sul state, Brazil. Based on the morphology of first stage larvae collected from a small fragment of the uterus of the adult nematode, the species was identified as Dracunculus sp. Reichard, 1759. Additionally, the morphological identification was molecularly confirmed by sequencing the cox1 gene. This report advocates for further investigations into the transmission cycle of this parasite in the Brazilian Pantanal wetland, considering the role of wildlife hosts and the zoonotic potential of Dracunculus species in that area.

What is the role of Swiss domestic cats in environmental contamination with Echinococcus multilocularis eggs?

BackgroundThe role of the domestic cat as definitive host for Echinococcus multilocularis and thus in environmental contamination with eggs has not yet been entirely resolved. This study aimed to assess the prevalence of E. multilocularis and other gastrointestinal parasites in Swiss domestic cats and to compare the diagnostic sensitivity of different methods for the detection of intestinal taeniid infection.MethodsFaecal samples from 146 cats were included in the study. Faecal samples only were available from 55 cats; for the other 91 cats, necropsy was performed in addition to faecal sample testing. All (n = 146) faecal samples were analysed by a combined sedimentation/flotation technique (44% ZnCl2) and by the sodium acetate-acetic acid-formalin (SAF) sedimentation technique; when sufficient material was available (n = 121 samples) the Baermann-Wetzel technique was also used. Additionally, all samples were analysed by two coproantigen (copro)-quantitative PCRs (qPCR): (i) a multiplex qPCR able to detect and differentiate between E. multilocularis, Echinococcus granulosus sensu lato and Taenia spp./other cestodes (CEST-qPCR) and (ii) an E. multilocularis-specific qPCR (EM-qPCR). Finally, the intestines were examined macroscopically and microscopically for parasite stages at necropsy (n = 91) and using an intestinal scraping technique (IST) (n = 64).ResultsOf the 146 cats examined, 24 (17.1%) were infected by intestinal parasites, namely Hydatigera (syn. Taenia) taeniaeformis (8.9%), Toxocara cati (6.1%), Capillaria sp. (3.4%), hookworms (3.4%), Mesocestoides litteratus (1.4%), Giardia sp. (1.4%), Cystoisospora rivolta (1.4%), Cystoisospora felis (0.7%), Toxoplasma gondii (0.7%), Hammondia hammondi (0.7%) and Strongyloides sp. (0.7%). Necropsy and the IST revealed adult H. taeniaeformis in 12 animals, of which eight faecal samples were positive by the CEST-qPCR (sensitivity = 67%) and six samples by the sedimentation/flotation technique (sensitivity = 50%). No E. multilocularis infection was detected in the sampled cats. Using Bayesian latent class analysis, the mean posterior prevalence probability was 0.0% (95% confidence interval 0–0.83%) for E. multilocularis.ConclusionsThere was no evidence of E. multilocularis infection among the 146 cats examined, suggesting that the prevalence of this parasite is low (< 1%) in the Swiss domestic cat population. Nonetheless, some of the sampled cats were infected by parasites that have rodents as intermediate hosts, demonstrating successful predation by these cats, and some were infected with zoonotic parasites. Cats therefore should not be disregarded as potential hosts for E. multilocularis and other zoonotic parasites.Graphical

First Insights into Population Structure and Genetic Diversity Versus Host Specificity in Trypanorhynch Tapeworms Using Multiplexed Shotgun Genotyping.

Theory predicts relaxed host specificity and high host vagility should contribute to reduced genetic structure in parasites while strict host specificity and low host vagility should increase genetic structure. Though these predictions are intuitive, they have never been explicitly tested in a population genomic framework. Trypanorhynch tapeworms, which parasitize sharks and rays (elasmobranchs) as definitive hosts, are the only order of elasmobranch tapeworms that exhibit considerable variability in their definitive host specificity. This allows for unique combinations of host use and geographic range, making trypanorhynchs ideal candidates for studying how these traits influence population-level structure and genetic diversity. Multiplexed shotgun genotyping (MSG) data sets were generated to characterize component population structure and infrapopulation diversity for a representative of each trypanorhynch suborder: the ray-hosted Rhinoptericola megacantha (Trypanobatoida) and the shark-hosted Callitetrarhynchus gracilis (Trypanoselachoida). Adults of R. megacantha are more host-specific and less broadly distributed than adults of C. gracilis, allowing correlation between these factors and genetic structure. Replicate tapeworm specimens were sequenced from the same host individual, from multiple conspecific hosts within and across geographic regions, and from multiple definitive host species. For R. megacantha, population structure coincided with geography rather than host species. For C. gracilis, limited population structure was found, suggesting a potential link between degree of host specificity and structure. Conspecific trypanorhynchs from the same host individual were found to be as, or more, genetically divergent from one another as from conspecifics from different host individuals. For both species, high levels of homozygosity and positive FIS values were documented.

Survey of the Prosthogonimus spp. metacercariae infection in the second intermediate host dragonfly in Heilongjiang Province, China.

Prosthogonimiasis poses a threat to the reproductive system of poultry and wild birds, which are the definitive hosts of the parasite causing this disease. However, the parasite infection of the second intermediate host (dragonfly), the primary vector of this pathogen, is rarely reported. In this study, the prevalence of Prosthogonimus infection in dragonflies was investigated from June 2019 to October 2022 in Heilongjiang Province, northeast China. The species of metacercariae isolated from dragonfly were identified by morphological characteristics, molecular biology techniques, and animal infection experiments. The results showed that 11 species of dragonflies and one damselfly were identified and among six of the dragonflies infected by Prosthogonimus metacercariae, Sympetrum depressiusculum (28.53%) had the highest infection rate among all positive dragonflies, followed by Sympetrum vulgatum (27.86%) and Sympetrum frequens (20.99%), which are preferred hosts, and the total prevalence was 20.39% (2061/10,110) in Heilongjiang Province. Three species of Prosthogoniumus metacercariae were isolated, including Prosthogonimus cuneatus, Prosthogonimus pullucidus, and Prosthogonimus sp., among which P. cuneatus was the dominant species in dragonflies in Heilongjiang Province. This is the first report on the prevalence of Prosthogonimus in dragonflies in China, which provides baseline data for the control of prosthogonimiasis in Heilongjiang Province and a reference for the prevention of prosthogonimiasis in other areas of China.

Long live the host! Proteomic analysis reveals possible strategies for parasitic manipulation of its social host.

Parasites with complex life cycles often manipulate the phenotype of their intermediate hosts to increase the probability of transmission to their definitive hosts. Infection with Anomotaenia brevis, a cestode that uses Temnothorax nylanderi ants as intermediate hosts, leads to a multiple-fold extension of host lifespan and to changes in behaviour, morphology and colouration. The mechanisms behind these changes are unknown, as is whether the increased longevity is achieved through parasite manipulation. Here, we demonstrate that the parasite releases proteins into its host with functions that might explain the observed changes. These parasitic proteins make up a substantial portion of the proteome of the hosts' haemolymph, and thioredoxin peroxidase and superoxide dismutase, two antioxidants, exhibited the highest abundances among them. The largest part of the secreted proteins could not be annotated, indicating they are either novel or severely altered during recent coevolution to function in host manipulation. We also detected shifts in the hosts' proteome with infection, in particular an overabundance of vitellogenin-like A in infected ants, a protein that regulates division of labour in Temnothorax ants, which could explain the observed behavioural changes. Our results thus suggest two different strategies that might be employed by this parasite to manipulate its host: secreting proteins with immediate influence on the host's phenotype and altering the host's translational activity. Our findings highlight the intricate molecular interplay required to influence the phenotype of a host and point to potential signalling pathways and genes involved in parasite-host communication.

First Molecular Detection of Neospora caninum in Feces of Grey Wolf (Canis lupus) and Golden Jackal (Canis aureus) Populations in Slovenia.

Neospora caninum is an obligate intracellular parasite that causes reproductive disorders and major economic losses in cattle, and induces neuromuscular disorders in canids. Exogenous infections are becoming increasingly important due to disease outbreaks. The sylvatic life cycle of N. caninum interferes with the domestic dog-ruminant life cycle, but understanding of it is scarce. The population of wild canids may play an important role in parasite dispersion. Feces from 42 grey wolves (Canis lupus) and 39 golden jackals (Canis aureus) were analyzed for the N. caninum Nc5 gene using a novel real-time PCR (qPCR) with a detection limit of 5 targets/µL in clinical samples. Three wolves (3/42; 7.1%) and one golden jackal (1/39; 2.6%) tested positive, which is the first detection of N. caninum in the population of grey wolves in Slovenia and the first detection of N. caninum DNA in the feces of a golden jackal. In addition to the grey wolf, we propose the golden jackal as a potential definitive host with hypothetical epidemiological importance for the sylvatic-domestic life cycle of N. caninum, due to its proximity to human habitats and its rapid expansion throughout Europe.

Molecular differentiation of Sarcocystis miescheriana and Sarcocystis suihominis using a new multiplex PCR targeting the mtDNA cox1 gene in wild boars in southern Italy

The increase of wild boar populations density and their meat consumption across Europe could expose humans to a plethora of foodborne diseases as sarcocystosis, caused by the zoonotic protozoan Sarcocystis suihominis. Humans become infected by eating raw or undercooked pig (Sus scrofa domesticus) containing S. suihominis sarcocysts. Despite this, to date very few data are available on the risk of infection by this parasite to wild boar (Sus scrofa) meat consumers. Thus, the present study aimed to assess the occurrence of Sarcocystis spp. in wild boars from southern Italy, applying both histology and a new multiplex PCR assay targeting the cox1 gene. Between 2019 and 2020, 997 muscle tissues (i.e., n = 269 oesophagus, n = 277 diaphragms, n = 298 hearts, n = 153 tongues) from 311 wild boars were collected and screened by a combined histological and molecular approach. Overall, 251 (80.7%) animals tested were positive for Sarcocystis spp., and S. miescheriana whose definitive hosts are canids, was the only molecularly identified species. A statistically significant difference (p < 0.05) in the prevalence of Sarcocystis infection was found according to the wild boar age and muscle tissue. Findings outlined the low zoonotic potential of infection to humans via wild boar meat consumption in Italy and the importance of the application of new molecular methods in distinguishing different Sarcocystis species.

An update and ecological perspective on certain sentinel helminth endoparasites within the Mediterranean Sea.

The Mediterranean Sea is recognized as a marine biodiversity hotspot. This enclosed basin is facing several anthropogenic-driven threats, such as seawater warming, pollution, overfishing, bycatch, intense maritime transport and invasion by alien species. The present review focuses on the diversity and ecology of specific marine trophically transmitted helminth endoparasites (TTHs) of the Mediterranean ecosystems, aiming to elucidate their potential effectiveness as ‘sentinels’ of anthropogenic disturbances in the marine environment. The chosen TTHs comprise cestodes and nematodes sharing complex life cycles, involving organisms from coastal and marine mid/upper-trophic levels as definitive hosts. Anthropogenic disturbances directly impacting the free-living stages of the parasites and their host population demographies can significantly alter the distribution, infection levels and intraspecific genetic variability of these TTHs. Estimating these parameters in TTHs can provide valuable information to assess the stability of marine trophic food webs. Changes in the distribution of particular TTHs species can also serve as indicators of sea temperature variations in the Mediterranean Sea, as well as the bioaccumulation of pollutants. The contribution of the chosen TTHs to monitor anthropogenic-driven changes in the Mediterranean Sea, using their measurable attributes at both spatial and temporal scales, is proposed.

A new species of Notocotylus (Digenea: Notocotylidae) from the black-necked swan Cygnus melancorhyphus (Molina) of Argentina.

Notocotylus cygni n. sp. is described here, taken from the intestine of the black-necked swan Cygnus melancoryphus (Molina) of Patagonia, Argentina. This new species differs from other members of the genus Notocotylus by having the genital pore anterior to the caecal bifurcation (located slightly posterior to oral sucker) and the unequal number and arrangement of ventral papillae (2-3 in the lateral rows and 10-12 in the median row). Phylogenetic analyses of the 28S and ITS1-5.8S ribosomal DNA (rRNA) sequences of the new species and other notocotylid trematodes available in GenBank indicate that N. cygni n. sp. is a sister taxon of Notocotylus fosteri Kinsella et Tkach, 2005, a trematode of the intestine of the rice rat Oryzomys palustris of Florida, United States. The new species differs from N. fosteri in the unequal number and arrangement of ventral papillae, number of uterine loops, size of the egg, definitive hosts (birds vs. mammals), and disparate environment and geographical distribution (freshwater environment in Patagonia vs. salt marsh in North America). This is the eighth species of Notocotylus reported from birds in Argentina, and the ninth species from the family Notocotylidae recorded in black-necked swans in South America.