Gastrointestinal parasites of Wolffsohn's viscacha (Chinchillidae: Lagidium wolffsohni), an endemic rodent species from the wild Patagonia

Parasites are ubiquitous in wildlife populations and have a profound impact on population dynamics. Interest in parasites of wildlife has increased significantly in recent years, particularly in those with relevant conservation status. Patagonia is one of the wildest and remote areas of the world. The Wolffsohn's viscacha lives in a small mountainous area of Patagonia. Until now, little is known about the biology and ecology of this species. The aim of this research was to study the gastrointestinal parasite diversity in this rodent from a coprological survey. A total of 125 fecal samples from 25 colonies were examined. Each sample was rehydrated, homogenized, and analyzed using three parasitological techniques: spontaneous sedimentation, Mini-FLOTAC, and centrifugation-flotation in sucrose-saturated solution, followed by examination under optical microscopy. The samples, eggs, and oocysts of parasites were described, measured, and photographed. All colonies were positive for at least one parasite species. A total of 10 parasitic species were identified: Viscachataenia sp., possibly V. quadrata, Monoecocestus sp., an unidentified anoplocephalid, Heteroxynema sp., possibly H. (Cavioxyura) viscaciae, Helminthoxys sp., possibly H. effilatus, an unidentified strongylid-type egg, Trichuris sp., two morphologies of unidentified coccidians and Eimeria sp. This is the first exhaustive study of gastrointestinal parasites in L. wolffsohni and a large number of eggs and oocysts of parasites were found. Our results highlight the use of noninvasive techniques for the study of parasites of wildlife hosts; as in the case of this rodent with a remote habitat, which makes sampling difficult. The results of our study provide baseline information on gastrointestinal parasite infections in this species.

Temporal change in the parasite community of an invasive fish Trachelyopterus galeatus (Siluriformes: Auchenipteridae) in a neotropical floodplain

The construction of dams and hydroelectric plants affects biodiversity in aquatic environments and can facilitate the invasion of species. Few studies assess the long-term response of parasite fauna under these events. The aim of this study was to investigate possible changes in the endoparasite composition of the invasive catfish Trachelyopterus galeatus (Linnaeus, 1766) in the floodplain of the upper Paraná River over a 27-year study period. A total of 79 fish were collected in period 1 (1993) and 31 in period 2 (2019/2020) at the same sampling points, and the endoparasites were located in the gastrointestinal system using a stereomicroscope. It was found that the development of the fish and the composition of their endoparasitic fauna changed over time. In the second period, the fish presented smaller values for mass (g) and standard length (cm) when compared to period 1. It was found that three species of endoparasites were found per period, but although the richness was the same, the composition differed, and only one digenean (Microrchis oligovitellum Lunaschi, 1987 (Trematoda: Paramphistomidae)) was shared. The Porto Primavera Dam was built upstream of the site between the sampling periods (1999) and caused a number of environmental changes, possibly being the main factor responsible for changes in components of the parasite community. Anthropic modification to an environment can cause loss of diversity and loss of ecological interactions. Through our results, we emphasize the importance of including parasite fauna in studies that assess environmental impacts.

Can Parasites be Useful?

Parasites are commonly associated with harm, but they also have beneficial aspects that are still being discovered. It is important to acknowledge both the harmful and beneficial aspects of parasites. They have been found to have positive effects on non-healing wounds, surgical wounds, obesity, glucose metabolism disorders, nerve repair, cancer treatments, and fertility. Research has shown that helminths, protozoa, and arthropods have the ability to correct, prevent, and cure certain disorders through the use of the parasite itself, its molecules, or even its eggs. This article includes studies on the beneficial aspects of parasites. However, further research is needed to fully understand the mechanisms by which parasites stimulate or affect the immune system and how they can be used therapeutically.

[Human parasites in surface water used for recreation in Salta, Argentina]

Waterborne diseases can have different origins, micro-organisms such as bacteria and parasites being the most important ones. In this study, two recreational aquatic environments were studied in the province of Salta, Argentina. Water samples collected from three different locations, two from a creek and one from the outlet of a thermal complex, were monitored at four time points. Physicochemical and microbiological characterization of each point was conducted, as well as a search for parasites and amebae. Parasites were identified through optical microscopy observations and free-living amebae (FLA) were isolated by spiking in Petri dishes followed by subsequent molecular identification. Water samples from the outlet of the thermal complex showed different physicochemical characteristics from those of the creek. Bacterial indicators of contamination were detected at all points; however, the creek water had a significantly higher concentration of Pseudomonas sp. Sporadically, creek samples exhibited Ascaris spp. eggs, Giardia sp. cysts, and ancylostomid eggs. The presence of FLA was observed in all samples, 15 of which were isolated and identified as Acanthamoeba sp., mostly belonging to the T4 genotype. Parasite surveillance in recreational aquatic environments is an important complement to traditional microbial indicators for assessing water quality. The identified parasites represent a potential health risk for people using these environments.

Parasites of Stray Cats in Iran: A Parasitological and Histopathological Study

Many zoonotic parasitic diseases, including Toxocara cati, may be spread by stray cat populations. This study aimed to determine the prevalence of parasites by performing parasitological and histopathological examinations on stray cats in Shiraz, Iran. A total of 106 stray cats from different geographical areas of Shiraz, southern Iran, were examined for the presence of parasites. The overall prevalence was found to be 83.02% (88/106), and eight parasites were found. The parasites included three genera of cestodes [Joyeuxiella echinorhynoides (52.83%), Taenia taeniaeformis (21.70%), and Dipylidium caninum (1.89%)], three nematodes [Physaloptera praeputialis (23.59%), Toxocara cati (15.09%), and Rictularia sp. (1.89%)], one protozoa [Isospora spp. (6.60%)], and one arthropod [Ctenocephalides felis (5.66%)]. The prevalence did not significantly differ between males and females. It did appear, nevertheless, that the age of cats may be regarded as a risk factor for these parasitic infections. Histopathological examination revealed some parasite-induced lesions in the intestine and stomach, including hyperemia, hemorrhage, mucosal destruction and inflammation. The lung tissues showed some histopathological lesions such as hemorrhage, edema, emphysema and mild inflammation, and dormant larvae were found in one tongue sample. The results of the present study showed that parasitic infections and, more importantly, T. cati are relatively prevalent in stray cats, and the people living in this area are at serious risk of this zoonotic disease. The cats in this region need to be monitored, and specific preventive measures should be developed by public health officials.

Parasites and Viruses in Callithrix in Brazil

PURPOSE

As a result of environmental imbalances of anthropogenic origin, the potential for transmission of parasites and viruses between different primates, including humans, might increase. Thus, parasitic studies have great relevance to primatology, which motivated us to conduct a literature review to synthesize the information available in American primates of the Callithrix genus.

METHODS

We carried out the bibliographic search on the main groups of parasites (protozoa, helminths, arthropods, ectoparasites) and viruses found in Callithrix in Brazil in search platforms and consider all manuscript that appeared in search engines, published between the years 1910 and December 2022. In each selected article, the following information was recorded: the host species; parasite taxa; scientific classification of the parasite; host habitat (free-living, captive); diagnostic technique; state; and bibliographic reference. Data were tabulated and arranged in a parasite-host table.

RESULTS

Some endemic genera, such as Callithrix, are widely distributed geographically across Brazil and have characteristics of adaptation to different habitats due to their flexibility in diet and behavior. These factors can make them subject to a greater diversity of parasites and viruses in the country. Here, we identified 68 parasitic taxa, belonging to the clades protozoa (n = 22), helminths (n = 34), ectoparasites (n = 7), and viruses (n = 5). Out of this total, 19 have zoonotic potential. Of the six existing marmoset species, Callithrix jacchus was the most frequent in studies, and Callithrix flaviceps did not have reports. All regions of the country had occurrences, mainly the Southeast, where 54% of the cases were reported. In 46% of the reported parasites and viruses, it was not possible to identify the corresponding species.

CONCLUSION

We conclude that in part of the works the identification methods are not being specific, which makes it difficult to identify the species that affects Callithrix spp. Furthermore, the studies present geographic disparities, being concentrated in the southeast of the country, making it impossible to have a more uniform analysis of the findings. Thus, it is observed that information about parasites and viruses is incipient in the genus Callithrix in Brazil.

Parasitic egg recognition using convolution and attention network

Intestinal parasitic infections (IPIs) caused by protozoan and helminth parasites are among the most common infections in humans in low-and-middle-income countries. IPIs affect not only the health status of a country, but also the economic sector. Over the last decade, pattern recognition and image processing techniques have been developed to automatically identify parasitic eggs in microscopic images. Existing identification techniques are still suffering from diagnosis errors and low sensitivity. Therefore, more accurate and faster solution is still required to recognize parasitic eggs and classify them into several categories. A novel Chula-ParasiteEgg dataset including 11,000 microscopic images proposed in ICIP2022 was utilized to train various methods such as convolutional neural network (CNN) based models and convolution and attention (CoAtNet) based models. The experiments conducted show high recognition performance of the proposed CoAtNet that was tuned with microscopic images of parasitic eggs. The CoAtNet produced an average accuracy of 93%, and an average F1 score of 93%. The finding opens door to integrate the proposed solution in automated parasitological diagnosis.

Distribution of Gastrointestinal Parasitic Infection in Domestic Pigs in the Republic of Korea: Nationwide Survey from 2020-2021

This study aimed to examine the distribution of gastrointestinal parasitic infections in domestic pigs in the Republic of Korea. From May 2020 to October 2021, 364 pig fecal samples were collected from 75 farms in 7 Provinces and microscopically examined. A total of 170 (46.7%) pigs were infected with at least one of the following parasites: Balantioides coli, strongyles, Ascaris suum, Trichuris suis, and coccidia. By parasite species, B. coli, strongyles, A. suum, T. suis, and coccidia oocysts or eggs were detected in 144 (39.6%), 24 (6.6%), 14 (3.8%), 4 (1.1%), and 1 (0.3%) samples, respectively. One hundred fifty-four, 15, and 1 cases showed single, double, and triple infections, respectively. Of the swine fecal samples from 75 farms, 69 specimens (92.0%) were infected with 1 or more parasites. All surveyed farms across the country exhibited a positive rate of over 30%, among which the highest positive rate was 65.0% in Chungcheongnam-do, and Jeollabuk-do was followed by 61.9%. Winter showed a statistically lower prevalence than other seasons. This study showed that gastrointestinal parasites are prevalent in pigs in Korea, although the diversity of parasites is low.

Endoparasitism of Golden Retrievers: Prevalence, risk factors, and associated clinicopathologic changes

Endoparasitism is a common disease in dogs throughout their lifetime despite the widespread availability of inexpensive diagnostic tests and effective treatments. The consequences of host parasite interactions in otherwise apparently healthy dogs remains largely unknown. This cross-sectional study used complete blood count, serum biochemistry, and fecal flotation data collected from 3,018 young dogs (<3 years of age) enrolled within the Morris Animal Foundation Golden Retriever Lifetime Study (GRLS) to determine the prevalence of endoparasitism and compare bloodwork values of parasite positive and negative participants using logistic regression. Variables including age, gender, reproductive status, and geographic region at the time of evaluation were assessed to identify potential associations. To the authors’ knowledge, a comprehensive assessment of clinicopathological changes associated with endoparasite infection in a large cohort has not been completed in the recent decade. The overall prevalence of endoparasitism was 6.99% (211/3018). Dogs who were parasite positive had statistically lower albumin (P = 0.004), lower RBC count (P = 0.01), higher neutrophil count (P = 0.002), and higher platelet count (P <0.001) as compared to parasite negative dogs. It was also concluded that dogs living in rural areas were more likely to have endoparasites than those living in suburban areas. Epidemiological data is crucial for the design and monitoring of prevention and control strategies. Identification of endoparasites by fecal testing is an essential tool to identify susceptible and resistant animals that can act as spreaders and reservoirs of intestinal parasites thereby enabling appropriate therapy and reducing the risk of new infection to animals and humans. Further epidemiological studies are needed to prevent, monitor, and develop new strategies to control endoparasites.

Prevalence of intestinal protozoan parasites among school children in africa: A systematic review and meta-analysis

Introduction

Parasitic infections, especially intestinal protozoan parasites (IPPs) remain a significant public health issue in Africa, where many conditions favour the transmission and children are the primary victims. This systematic review and meta-analysis was carried out with the objective of assessing the prevalence of IPPs among school children in Africa.

Methods

Relevant studies published between January 2000 and December 2020 were identified by systematic online search on PubMed, Web of Science, Embase and Scopus databases without language restriction. Pooled prevalence was estimated using a random-effects model. Heterogeneity of studies were assessed using Cochrane Q test and I² test, while publication bias was evaluated using Egger’s test.

Results

Of the 1,645 articles identified through our searches, 46 cross-sectional studies matched our inclusion criteria, reported data from 29,968 school children of Africa. The pooled prevalence of intestinal protozoan parasites amongst African school children was 25.8% (95% CI: 21.2%-30.3%) with E. histolytica/ dispar (13.3%; 95% CI: 10.9%-15.9%) and Giardia spp. (12%; 95% CI: 9.8%-14.3%) were the most predominant pathogenic parasites amongst the study participants. While E. coli was the most common non-pathogenic protozoa (17.1%; 95% CI: 10.9%-23.2%).

Conclusions

This study revealed a relatively high prevalence of IPPs in school children, especially in northern and western Africa. Thus, poverty reduction, improvement of sanitation and hygiene and attention to preventive control measures will be the key to reducing protozoan parasite transmission.

Pathogenic intestinal protozoan parasites (IPPs) remain a major public health concern. Studies have documented that, the prevalence rates of protozoan infections are quite high in developing regions, particularly Africa and children are the primary victims. Despite numerous studies have been conducted on IPPs in school children in African countries, data on the burden of these infections in African school children have not yet been synthesised. This systematic review and meta-analysis was conducted to provide continent-wide prevalence of IPPs amongst African school children. Our study found that about 25.8% of the children had one or more species of intestinal protozoan parasites in their faecal specimens. E. histolytica/ dispar and Giardia spp. were the most predominant parasites amongst the study participants. The relatively high prevalence estimate of IPPs amongst African children and the considerable variation in the disease prevalence over the years, between and within countries and regions clearly indicates the needs to improve sanitation and hygiene, paying more attention to preventive control measures as well as poverty reduction which are the key to reducing protozoan parasite transmission.

Micronutrient supplements can promote disruptive protozoan and fungal communities in the developing infant gut

Supplementation with micronutrients, including vitamins, iron and zinc, is a key strategy to alleviate child malnutrition. However, association of gastrointestinal disorders with iron has led to ongoing debate over their administration. To better understand their impact on gut microbiota, we analyse the bacterial, protozoal, fungal and helminth communities of stool samples collected from a subset of 80 children at 12 and 24 months of age, previously enrolled into a large cluster randomized controlled trial of micronutrient supplementation in Pakistan (ClinicalTrials.gov identifier NCT00705445). We show that while bacterial diversity is reduced in supplemented children, vitamins and iron (as well as residence in a rural setting) may promote colonization with distinct protozoa and mucormycetes, whereas the addition of zinc appears to ameliorate this effect. We suggest that the risks and benefits of micronutrient interventions may depend on eukaryotic communities, potentially exacerbated by exposure to a rural setting. Larger studies are needed to evaluate the clinical significance of these findings and their impact on health outcomes.

Relaxed selection underlies genome erosion in socially parasitic ant species

Inquiline ants are highly specialized and obligate social parasites that infiltrate and exploit colonies of closely related species. They have evolved many times convergently, are often evolutionarily young lineages, and are almost invariably rare. Focusing on the leaf-cutting ant genus Acromyrmex, we compared genomes of three inquiline social parasites with their free-living, closely-related hosts. The social parasite genomes show distinct signatures of erosion compared to the host lineages, as a consequence of relaxed selective constraints on traits associated with cooperative ant colony life and of inquilines having very small effective population sizes. We find parallel gene losses, particularly in olfactory receptors, consistent with inquiline species having highly reduced social behavioral repertoires. Many of the genomic changes that we uncover resemble those observed in the genomes of obligate non-social parasites and intracellular endosymbionts that branched off into highly specialized, host-dependent niches.

Zoonotic parasitic organisms on vegetables: Impact of production system characteristics on presence, prevalence on vegetables in northwestern Iran and washing methods for removal

Fresh vegetables are essential components of a healthy and nutritious diet, but if consumed raw without proper washing and/or disinfection, can be important agents of transmission of enteric pathogens. This study aimed to determine the prevalence of zoonotic parasites on vegetables freshly harvested and "ready to eat" vegetables from greengrocers and markets in northwestern Iran. In addition, the effect of cropping system and season on contamination levels were assessed as well as the efficacy of washing procedures to remove parasites from the vegetables. A total of 2757 samples composed of field (n = 1, 600) and "ready to eat" (n = 1157) vegetables were analyzed. Vegetables included leek, parsley, basil, coriander, savory, mint, lettuce, cabbage, radish, dill, spinach, mushroom, carrot, tomato, cucumber and pumpkin. Normal physiological saline washings from 200 g samples were processed using standard parasitological techniques and examined microscopically. A total of 53.14% of vegetable samples obtained from different fields and 18.23% of "ready to eat" vegetables purchased from greengrocers and markets were contaminated with different parasitic organisms including; Entamoeba coli cysts, Giardia intestinalis cysts, Cryptosporidium parvum oocysts, Fasciola hepatica eggs, Dicrocoelium dendriticum eggs, Taenia spp. eggs, Hymenolepis nana eggs, Ancylostoma spp. eggs, Toxocara cati eggs, Toxocara canis eggs, Strongyloides stercoralis larvae, and Ascaris lumbricoides eggs. In both field and "ready to eat" vegetables, the highest parasitic contamination was observed in lettuce with a rate of 91.1% and 55.44%, respectively. The most common parasitic organism was Fasciola hepatica. A seasonal difference in contamination with parasitic organisms was found for field and "ready to eat" vegetables (P < 0.05). There was a significant difference in the recovery of parasitic organisms depending on the washing method with water and dishwashing liquid being the least effective. Proper washing of vegetables is imperative for a healthy diet as the results of this study showed the presence of zoonotic parasites from field and ready to eat vegetables in Iran.

High prevalence of intestinal parasite infestations among stunted and control children aged 2 to 5 years old in two neighborhoods of Antananarivo, Madagascar

BACKGROUND

This study aimed to compare the prevalence of intestinal parasite infestations (IPIs) in stunted children, compared to control children, in Ankasina and Andranomanalina Isotry (two disadvantaged neighborhoods of Antananarivo, Madagascar), to characterize associated risk factors and to compare IPI detection by real-time PCR and standard microscopy techniques.

METHODOLOGY/PRINCIPAL FINDINGS

Fecal samples were collected from a total of 410 children (171 stunted and 239 control) aged 2-5 years. A single stool sample per subject was examined by simple merthiolate-iodine-formaldehyde (MIF), Kato-Katz smear and real-time PCR techniques. A total of 96.3% of the children were infested with at least one intestinal parasite. The most prevalent parasites were Giardia intestinalis (79.5%), Ascaris lumbricoides (68.3%) and Trichuris trichiura (68.0%). For all parasites studied, real-time PCR showed higher detection rates compared to microscopy (G. intestinalis [77.6% (n = 318) versus 20.9% (n = 86)], Entamoeba histolytica [15.8% (n = 65) versus 1.9% (n = 8)] and A. lumbricoides [64.1% (n = 263) versus 50.7% (n = 208)]). Among the different variables assessed in the study, age of 4 to 5 years (AOR = 4.61; 95% CI, (1.35-15.77)) and primary and secondary educational level of the mother (AOR = 12.59; 95% CI, (2.76-57.47); AOR = 9.17; 95% CI, (2.12-39.71), respectively) were significantly associated with IPIs. Children drinking untreated water was associated with infestation with G. intestinalis (AOR = 1.85; 95% CI, (1.1-3.09)) and E. histolytica (AOR = 1.9; 95% CI, (1.07-3.38)). E. histolytica was also associated with moderately stunted children (AOR = 0.37; 95% CI, 0.2-0.71). Similarly, children aged between 4 and 5 years (AOR = 3.2; 95% CI (2.04-5.01)) and living on noncemented soil types (AOR = 1.85; 95% CI, (1.18-2.09)) were associated with T. trichiura infestation.

CONCLUSIONS/SIGNIFICANCE

The prevalence of IPIs is substantial in the studied areas in both stunted and control children, despite the large-scale drug administration of antiparasitic drugs in the country. This high prevalence of IPIs warrants further investigation. Improved health education, environmental sanitation and quality of water sources should be provided.

Intestinal parasitic infections in a population of BaAka Pygmies inhabiting the Congo Basin in the Central African Republic

INTRODUCTION

Pygmy tribes inhabit tropical environment of Central Africa. After expulsion from their original habitat by the Bantu people, they settled in a local forest ecosystem where they live with very low sanitary standards. Their actual morbidity remains unknown.

OBJECTIVE

The aim of the study was to analyze the prevalence of intestinal parasitic infections in BaAka Pygmies inhabiting the Congo Basin in the Central African Republic.

MATERIAL AND METHODS

The study was conducted in 2015, and involved a group of 950 Pygmies living inthe Sangha-Mbaere and Lobaye prefectures. Single stool samples were collected from study participants, fixed in 10% formalin, transported from Africa to Europe, and analyzed by light microscopy using 5 different diagnostic methods (direct smear, decantation with distilled water, Fülleborne's flotation, Kato-Miura thick smear, DiaSyS/PARASYS system sedimentation) at the Military Institute of Medicine in Warsaw, Poland.

RESULTS

Microscopic examination revealed infections with 14 different species of intestinal nematodes, cestodes, trematodes and protozoa. According to the study findings, 90.5% of BaAka Pygmies were found to be infected with intestinal parasites, and 70.8% had mixed infections. Most of the pathogenic intestinal parasites were nematodes (85.0%), with Asrcaris lumbricoides (29.8%), hookworm (29.4%) and Trichuris trichiura (10.7%) being predominant.

CONCLUSIONS

Poor sanitation, limited the high prevalence of intestinal parasitic infections in the community of Pygmies. The negative test results may prove the effectiveness of periodic deworming campaigns chich, implemented by non-governmental organizations, are voluntary with respect to the informed consent principle.

A comparative analysis of deep learning architectures on high variation malaria parasite classification dataset

Malaria, one of the leading causes of death in underdeveloped countries, is primarily diagnosed using microscopy. Computer-aided diagnosis of malaria is a challenging task owing to the fine-grained variability in the appearance of some uninfected and infected class. In this paper, we transform a malaria parasite object detection dataset into a classification dataset, making it the largest malaria classification dataset (63,645 cells), and evaluate the performance of several state-of-the-art deep neural network architectures pretrained on both natural and medical images on this new dataset. We provide detailed insights into the variation of the dataset and qualitative analysis of the results produced by the best models. We also evaluate the models using an independent test set to demonstrate the model's ability to generalize in different domains. Finally, we demonstrate the effect of conditional image synthesis on malaria parasite detection. We provide detailed insights into the influence of synthetic images for the class imbalance problem in the malaria diagnosis context.

Sensitive universal detection of blood parasites by selective pathogen-DNA enrichment and deep amplicon sequencing

BACKGROUND

Targeted amplicon deep sequencing (TADS) has enabled characterization of diverse bacterial communities, yet the application of TADS to communities of parasites has been relatively slow to advance. The greatest obstacle to this has been the genetic diversity of parasitic agents, which include helminths, protozoa, arthropods, and some acanthocephalans. Meanwhile, universal amplification of conserved loci from all parasites without amplifying host DNA has proven challenging. Pan-eukaryotic PCRs preferentially amplify the more abundant host DNA, obscuring parasite-derived reads following TADS. Flaherty et al. (2018) described a pan-parasitic TADS method involving amplification of eukaryotic 18S rDNA regions possessing restriction sites only in vertebrates. Using this method, host DNA in total DNA extracts could be selectively digested prior to PCR using restriction enzymes, thereby increasing the number of parasite-derived reads obtained following NGS. This approach showed promise though was only as sensitive as conventional PCR.

RESULTS

Here, we expand on this work by designing a second set of pan-eukaryotic primers flanking the priming sites already described, enabling nested PCR amplification of the established 18S rDNA target. This nested approach facilitated introduction of a second restriction digestion between the first and second PCR, reducing the proportional mass of amplifiable host-derived DNA while increasing the number of PCR amplification cycles. We applied this method to blood specimens containing Babesia, Plasmodium, various kinetoplastids, and filarial nematodes and confirmed its limit of detection (LOD) to be approximately 10-fold lower than previously described, falling within the range of most qPCR methods.

CONCLUSIONS

The assay detects and differentiates the major malaria parasites of humans, along with several other clinically important blood parasites. This represents an important step towards a TADS-based universal parasite diagnostic (UPDx) test with a sufficient LOD for routine applications. Video Abstract.

Globalisation and Ocular Parasitic Infections: A Review of Recent Studies

Ocular parasitic infections, which lead to significant morbidity and mortality in particular areas, have been shifting from endemic areas to other regions due to tourism, wars and migrations in recent years. This study aimed to review the parasitic factors related to the human eye and their geographical distribution, pathogenesis of the disease and the methods used in and studies conducted for its diagnosis. PubMed, MEDLINE and Google databases were researched and reviewed for relevant keywords in recent publications. Although such parasitic infections are rare in many parts of the world, they continue to be an important public health problem that affects human and animal health in places with poor health conditions. The distribution of ocular parasites and their spread to non-endemic areas are facilitated. The morbidity and mortality risks have been increasing due to the difficulties encountered by health personnel in the diagnosis of these parasitic infections. Defining them accurately and appropriately can save not only eyesight but also lives.

Bat parasites (Acari, Anoplura, Cestoda, Diptera, Hemiptera, Nematoda, Siphonaptera, Trematoda) in France (1762-2018): a literature review and contribution to a checklist

This paper is a bibliographical survey of records of bat parasites in France (including Corsica) between 1762 and 2018. In total, 237 scientific publications were analysed. They show that bats are infected with a large diversity of endoparasites and ectoparasites. A total of 113 parasite taxa were identified from 27 host species; in addition, six bats were not identified to the species-level. The helminth fauna of bats comprises three species of Cestoda, 15 of Trematoda, and 13 of Nematoda. Acari parasites include 53 species (in addition to 22 invalid species). Finally, insect parasites comprise 13 species of Diptera (bat flies), 12 of Siphonaptera (fleas), 3 of Hemiptera (bugs), and 1 Anoplura species. Bat taxa reported with parasites were Barbastella barbastellus, Eptesicus serotinus, Hypsugo savii, Miniopterus schreibersii, Myotis bechsteinii, M. blythii, M. capaccinii, M. dasycneme, M. daubentonii, M. emarginatus, M. myotis, M. mystacinus, M. nattereri, M. punicus, Nyctalus lasiopterus, N. leisleri, N. noctula, Pipistrellus kuhlii, P. nathusii, P. pipistrellus, Plecotus auritus, P. austriacus, Rhinolophus euryale, R. ferrumequinum, R. hipposideros, R. mehelyi, Tadarida teniotis, Eptesicus sp., Myotis sp., Pipistrellus sp., Plecotus sp., Rhinolophus sp. and the species complex Pipistrellus pipistrellus/kuhlii/nathusii. As regards E. nilssonii, Vespertilio murinus (Particoloured Bat), M. alcathoe, M. escalerai, P. macrobullaris and P. pygmaeus, no records were found. These published field data originated from 72 of the 96 departments in metropolitan France. The most commonly cited were Ardèche, Ariège, Bouches-du-Rhône, Haute-Savoie, Maine-et-Loire, Moselle, Meurthe-et-Moselle, Pyrénées-Orientales, Sarthe, Haute-Corse and Corse-du-Sud.

Reductionist Pathways for Parasitism in Euglenozoans? Expanded Datasets Provide New Insights

The unicellular trypanosomatids belong to the phylum Euglenozoa and all known species are obligate parasites. Distinct lineages infect plants, invertebrates, and vertebrates, including humans. Genome data for marine diplonemids, together with freshwater euglenids and free-living kinetoplastids, the closest known nonparasitic relatives to trypanosomatids, recently became available. Robust phylogenetic reconstructions across Euglenozoa are now possible and place the results of parasite-focused studies into an evolutionary context. Here we discuss recent advances in identifying the factors shaping the evolution of Euglenozoa, focusing on ancestral features generally considered parasite-specific. Remarkably, most of these predate the transition(s) to parasitism, suggesting that the presence of certain preconditions makes a significant lifestyle change more likely.

Spiral valve parasites of blue and common thresher sharks as indicators of shark feeding behaviour and ecology

This study documented the parasite faunas of the spiral valves of blue sharks Prionace glauca (L. 1758) and common thresher sharks Alopias vulpinus (Bonnaterre, 1788) caught in the California Current Large Marine Ecosystem (CCLME) north of the Mexican border. The spiral valves of 18 blue and 19 thresher sharks caught in the CCLME from 2009 to 2013 were examined for parasites. Seven parasite taxa were found in blue sharks and nine in threshers. The tetraphyllidean cestode Anthobothrium sp. (78% prevalence) was the most common parasite in blue sharks, and the phyllobothriid cestode Paraorygmatobothrium sp. (90% prevalence) was the most common in threshers. An adult nematode of the genus Piscicapillaria was found in threshers for the first time and may be a new species. Adult individuals of Hysterothylacium sp. were found in both shark species. The adult acanthocephalan Rhadinorhynchus cololabis and remains of the parasitic copepod Pennella sp. - both parasites of Pacific saury, Cololabis saira - were found in the intestines of threshers, indicating recent feeding on saury. This study paves the way for a more comprehensive examination, including more samples and a wider variety of shark species, to provide a greater understanding of shark feeding behaviour and possibly provide information on shark population biology.

Evaluation and utility of mitochondrial ribosomal genes for molecular systematics of parasitic nematodes

BACKGROUND

Molecular advances have accelerated our understanding of nematode systematics and taxonomy. However, comparative analyzes between various genetic markers have led to discrepancies in nematode phylogenies. This study aimed to evaluate the suitability of using mitochondrial 12S and 16S ribosomal RNA genes for nematode molecular systematics.

METHODS

To study the suitability of mitochondrial 12S and 16S ribosomal RNA genes as genetic markers for nematode molecular systematics, we compared them with the other commonly used genetic markers, nuclear internal transcribed spacer 1 and 2 regions, nuclear 18S and 28S ribosomal RNA genes, and mitochondrial cytochrome c oxidase subunit 1 gene. After that, phylum-wide primers for mitochondrial 12S and 16S ribosomal RNA genes were designed, and parasitic nematodes of humans and animals from 75 taxa with 21 representative species were inferred through phylogenetic analyzes. Phylogenetic analyzes were carried out using maximum likelihood and Bayesian inference algorithms.

RESULTS

The phylogenetic relationships of nematodes based on the mitochondrial 12S rRNA gene supported the monophyly of nematodes in clades I, IV, and V, reinforcing the potential of this gene as a genetic marker for nematode systematics. In contrast, the mitochondrial 16S rRNA gene only supported the monophyly of clades I and V, providing evidence that the 12S rRNA gene is more suitable for nematode molecular systematics. In this study, subclades of clade III containing various nematode families were not monophyletic when the 16S or 12S rRNA gene was used as the genetic marker. This is similar to the phylogenetic relationship revealed by previous studies using whole mitochondrial genomes as genetic markers.

CONCLUSIONS

This study supports the use of the 12S rRNA gene as a genetic marker for studying the molecular systematics of nematodes to understand intra-phyla relationships. Phylum-wide primers for nematodes using mitochondrial ribosomal genes were prepared, which may enhance future studies. Furthermore, sufficient genetic variation in the mitochondrial 12S and 16S rRNA genes between species also allowed for accurate taxonomy to species level, revealing the potential of these two genes as genetic markers for DNA barcoding.

Photoparasitism as an Intermediate State in the Evolution of Apicomplexan Parasites

Despite the benefits of phototrophy, many algae have lost photosynthesis and have converted back to heterotrophy. Parasitism is a heterotrophic strategy, with apicomplexans being among the most devastating parasites for humans. The presence of a nonphotosynthetic plastid in apicomplexan parasites suggests their phototrophic ancestry. The discovery of related phototrophic chromerids has unlocked the possibility to study the transition between phototrophy and parasitism in the Apicomplexa. The chromerid Chromera velia can live as an intracellular parasite in coral larvae as well as a free-living phototroph, combining phototrophy and parasitism in what I call photoparasitism. Since early-branching apicomplexans live extracellularly, their evolution from an intracellular symbiont is unlikely. In this opinion article I discuss possible evolutionary trajectories from an extracellular photoparasite to an obligatory apicomplexan parasite.

Protist enteroparasites in wild boar (Sus scrofa ferus) and black Iberian pig (Sus scrofa domesticus) in southern Spain: a protective effect on hepatitis E acquisition?

BACKGROUND

Several studies have independently evaluated the occurrence of hepatitis E virus (HEV) and enteroparasites in swine, but no surveys have been conducted to jointly assess the prevalence and genetic diversity of enteroparasites in pigs and wild boars, their sympatric transmission between hosts, and their potential interaction with HEV.

METHODS

We prospectively collected serum and faecal samples from black Iberian domestic pigs and wild boars from southern Spain between 2015‒2016. We evaluated for HEV in serum and faeces, and for the presence of enteroparasites (Giardia duodenalis, Cryptosporidium spp., Blastocystis sp., Neobalantidium coli and Strongyloides spp.) in the same faecal samples. The prevalence of each intestinal parasite species was calculated.

RESULTS

A total of 328 animals (56.7% black Iberian pigs and 43.3% wild boars) were included in the study. The overall global prevalence of HEV in serum was 16.8%. The overall global prevalence of each enteroparasite species was 19.5% for G. duodenalis, 8.2% for Cryptosporidium spp., 41.8% for Blastocystis sp., 31.4% for N. coli, and 8.8% for Strongyloides spp. HEV-infected animals showed a significantly lower prevalence of G. duodenalis (3.2 vs 20%; P = 0.002) and Blastocystis sp. (38.7 vs 80%; P < 0.001) than those uninfected by HEV. Animals carrying G. duodenalis and Blastocystis sp. infections showed a significantly lower rate of HEV infection than those not harbouring these enteroparasites (P < 0.001).

CONCLUSIONS

Our study found a high prevalence of enteroparasites in black Iberian pigs and wild boars in southern Spain, suggesting a sympatric co-transmission of some of the species investigated. It is suggested that extracellular G. duodenalis and Blastocystis sp. might have a protective effect on HEV acquisition in swine.

Detection of gastrointestinal parasitism at recreational canine sites in the USA: the DOGPARCS study

BACKGROUND

The rapid growth in off-leash dog parks provides opportunity for canine socialization activities but carries risk of exposure to intestinal parasites. This study assessed the prevalence of these infections in dogs visiting off-leash dog parks.

METHODS

Fresh defecations were collected from dogs visiting parks in 30 metropolitan areas across the USA. Samples were analyzed by coproantigen immunoassay (CAI) (Fecal Dx® and Giardia Test, IDEXX Laboratories, Inc.) and zinc sulfate centrifugal flotation (CF). Owners responded to a questionnaire on their dog's signalment and use of heartworm/intestinal parasite control medications (HWCM).

RESULTS

Samples were examined from 3006 dogs, 87.9% aged at least 12 months, visiting 288 parks. At least one intestinal parasite was detected in 622 (20.7%) samples, nematodes in 263 (8.8%), with hookworms, whipworms and ascarids in 7.1, 1.9 and 0.6% of samples, respectively. A sample positive for one or more intestinal parasites was found in 245 (85.1%) parks, with nematodes found in 143 (49.7%). Combined, CAI and CF detected 78.4% more intestinal nematode infections than CF alone. Hookworm and whipworm infections were detected in all age groups, but ascarids were only detected in dogs less than 4 years-old. Approximately 42% of dogs aged less than 1 year were positive for nematodes or Giardia. Based on owner reports, HWCM was current for 68.8% of dogs, dogs previously diagnosed with intestinal parasitism were more likely to be receiving a HWCM than those without such history, and a significantly lower (P = 0.0003) proportion of dogs receiving a HWCM were positive for intestinal nematodes compared with those not on such medication.

CONCLUSIONS

Intestinal parasites, the most common of which were Giardia, Ancylostoma caninum and Trichuris vulpis, were found in 20% of dogs and 85% of dog parks across the USA. Enhanced detection of canine intestinal parasitism was achieved by combining CF and CAI. Canine intestinal parasites are common across the USA and dog health can be improved by regular testing of fecal samples and routine administration of medications effective against the most common infections.