Epidémiosurveillance et circulation des parasites dans les environnements

The morbidity due to congenital toxoplasmosis in humans is very high. Most of these infected children are likely to develop symptoms of clinical toxoplasmosis. Sequelae in fetus resulting from Toxoplasma gondii infections in women who become infected with this parasite during pregnancy can be devastating and enormous efforts are directed in some countries to prevent these consequences. Here, an update on congenital toxoplasmosis in humans, especially the rate of congenital infections in humans worldwide, is provided. Although several countries have surveillance programmes, most information on the rate of congenital transmission is from France and Brazil. Because of compulsory national screening programme in France to detect and treat women with recently acquired T. gondii infection with anti-toxoplasma therapy, the rate of congenital transmission and the severity of disease in children are declining. Infections by this parasite are widely prevalent in Brazil. The severity of clinical toxoplasmosis in Brazilian children is very high and may be associated with the genetic characteristics of T. gondii isolates prevailing in animals and humans in Brazil. Virtually little or no information is available on this topic from China, India and other countries in Asia.

Background: The intensification of trade and travel is linked to the growing number of imported cases of dengue, chikungunya or Zika viruses into continental Europe and to the expansion of invasive mosquito species such as Aedes albopictus and Aedes japonicus. Local outbreaks have already occurred in several European countries. Very little information exists on the vector competence of native mosquitoes for arboviruses. As such, the vectorial status of the nine mosquito species largely established in North-Western Europe (Aedes cinereus and Aedes geminus, Aedes cantans, Aedes punctor, Aedes rusticus, Anopheles claviger s.s., Anopheles plumbeus, Coquillettidia richiardii, Culex pipiens s.l., and Culiseta annulata) remains mostly unknown. Objectives: To review the vector competence of both invasive and native mosquito populations found in North-Western Europe (i.e., France, Belgium, Germany, United Kingdom, Ireland, The Netherlands, Luxembourg and Switzerland) for dengue, chikungunya, Zika, West Nile and Usutu viruses. Methods: A bibliographical search with research strings addressing mosquito vector competence for considered countries was performed. Results: Out of 6357 results, 119 references were related to the vector competence of mosquitoes in Western Europe. Eight species appear to be competent for at least one virus. Conclusions: Aedes albopictus is responsible for the current outbreaks. The spread of Aedes albopictus and Aedes japonicus increases the risk of the autochthonous transmission of these viruses. Although native species could contribute to their transmission, more studies are still needed to assess that risk.

The foodborne disease burden (FBDB) related to 26 major biological hazards in France was attributed to foods and poor food-handling practices at the final food preparation step, in order to develop effective intervention strategies, especially food safety campaigns. Campylobacter spp. and non-typhoidal Salmonella accounted for more than 60% of the FBDB. Approximately 30% of the FBDB were attributed to 11 other hazards including bacteria, viruses and parasites. Meats were estimated as the main contributing food category causing (50–69%) (CI90) of the FBDB with (33–44%), (9–21%), (4–20%) (CI90) of the FBDB for poultry, pork and beef, respectively. Dairy products, eggs, raw produce and complex foods caused each approximately (5–20%) (CI90) of the FBDB. When foods are contaminated before the final preparation step, we estimated that inadequate cooking, cross-contamination and inadequate storage contribute for (19–49%), (7–34%) and (9–23%) (CI90) of the FBDB, respectively; (15–33%) (CI90) of the FBDB were attributed to the initial contamination of ready-to-eat foods—without any contribution from final food handlers. The thorough implementation of good hygienic practices (GHPs) at the final food preparation step could potentially reduce the FBDB by (67–85%) (CI90) (mainly with the prevention of cross-contamination and adequate cooking and storage).

The present paper summarizes prevalence, epidemiology and clinical disease of natural Toxoplasma gondii infections in humans and animals from Egypt. The current situation of toxoplasmosis in Egypt is confusing. There is no central laboratory or group of researchers actively investigating toxoplasmosis in humans or animals, and no reports on the national level are available. Based on various serological tests and convenience samples, T. gondii infections appear highly prevalent in humans and animals from Egypt. Living circumstances in Egypt favour the transmission of T. gondii. Up to 95% of domestic cats, the key host of T. gondii, are infected with T. gondii; they are abundant in rural and suburban areas, spreading T. gondii oocysts. Many women have been tested in maternity clinics, most with no definitive diagnosis. Toxoplasma gondii DNA and IgM antibodies have been found in blood samples of blood donors. Clinical toxoplasmosis in humans from Egypt needs further investigations using definitive procedures. Reports on congenital toxoplasmosis are conflicting and some reports are alarming. Although there are many serological surveys for T. gondii in animals, data on clinical infections are lacking. Here, we critically review the status of toxoplasmosis in Egypt, which should be useful to biologist, public health workers, veterinarians and physicians.

Cryptosporidiosis is currently recognized worldwide as a leading cause of moderate to severe diarrhea. In Europe, large water- and foodborne outbreaks have been reported, highlighting the widespread distribution of the parasite and its important health impact. Surveillance networks have been progressively set up and the aim of this study was to present recent epidemiological data obtained in France from 2017 to 2019 by the National Reference Center—Expert Laboratory of cryptosporidiosis (Centre National de Référence–Laboratoire Expert cryptosporidioses CNR-LE). Data were obtained from online reports of volunteer network participants and stools were sent to the CNR-LE for species identification and GP60 genotyping. During this period, data from 750 online reports were available. Cryptosporidiosis occurred predominantly in young children (<5 years old) and in young adults, especially during late summer. Most patients were immunocompetent (60%), and deaths were reported only in immunocompromised patients. Cryptosporidium parvum was largely predominant (72% of cases) over C. hominis (24%) and some other uncommon species. C. parvum GP60 subtypes IIa and IId were the most represented, which suggests frequent zoonotic transmission. For C. hominis, subtypes IbA10G2 and IaA22R2 were predominant.

Abstract The world's parasitic and mutualistic biodiversity is undergoing major upheavals related to modifications in host community structures, changes in interactions between species, and through coextinction events. Trematodes are an important component of this invisible biodiversity, in terms of species richness, but also because of their role in ecosystems functioning and in the emergence of associated diseases. Taken together, these elements point to the need for a better assessment and understanding of the structure and dynamics of trematode diversity. In this context, our aim was to develop an optimized eDNA‐based metabarcoding approach to detect trematodes and characterize their communities, most of which associated with aquatic environments. The efficiency of this newly developed tool was first assessed by exhaustive in‐silico and in‐vitro validation steps. We next assessed the ability of our eDNA‐based approach to reconstruct trematode communities compared to a classical trematode monitoring method over four freshwater aquatic ecosystems. Our eDNA‐based monitoring tool displayed a high amplification enrichment of trematode DNA, a 100% detection score for tracking back an in‐vitro mock community composed of 28 trematode species, and high genetic resolution, which makes it relevant to discriminate between even phylogenetically close trematode species. Over the four natural ecosystems screened in natura , 33 OTUs were generated from the eDNA‐based approach, from which 11 trematode species were identified. In comparison, we identified five trematode species using the classical monitoring method, three of which were also detected by the eDNA‐based approach. We believe that this new eDNA‐based metabarcoding tool will open new perspectives for fundamental and applied research in community ecology, conservation, and health survey.

DNA metabarcoding of faecal samples is being successfully used to study the foraging niche of species. We assessed the ability of two benchtop high-throughput sequencing (HTS) platforms, to identify a large taxonomic array of food items from domestic cats Felis silvestris catus, including prey and human-related food taxa (pet food and leftovers leaving undetectable solid remains in faeces). Scats from a captive feeding trial (n = 41) and from free-ranging individuals (n = 326) were collected and analysed using a cytb mini-barcode in independent PCR replicates on the Ion PGM and the MiSeq platforms. Outputs from MiSeq were more sensitive and reproducible than those from Ion PGM due to a higher sequencing depth and sequence quality on MiSeq. DNA from intact prey taxa was detected more often (82% of the expected occurrences) than DNA from pet food (54%) and raw fish and meat (31%). We assumed that this variability was linked to different degree of DNA degradation: The Ion PGM detected significantly less human-linked food, birds, field voles, murids and shrews in the field-collected samples than the MiSeq platform. Pooling the replicates from both platforms and filtering the data allowed identification of at least one food item in 87.4% of the field-collected samples. Our DNA metabarcoding approach identified 29 prey taxa, of which 25 to species level (90% of items) including 9 rodents, 3 insectivores, 12 birds and 1 reptile and 33 human-related food taxa of which 23 were identified to genus level (75% of items). Our results demonstrate that using HTS platforms such as MiSeq, which provide reads of sufficiently high quantity and quality, with sufficient numbers of technical replicates, is a robust and non-invasive approach for further dietary studies on animals foraging on a wide range of food items in anthropogenic landscapes.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-ToF MS) is routinely used in mycology laboratories to rapidly identify pathogenic yeasts. Various methods have been proposed to perform routine MS-based identification of clinically relevant species. In this study, we focused on Bruker technology and assessed the identification performance of three protocols: two pretreatment methods (rapid formic acid extraction directly performed on targets and full extraction using formic acid/acetonitrile in tubes) and a direct deposit protocol that omits the extraction step. We also examined identification performance using three target types (ground-steel, polished-steel, and biotargets) and two databases (Bruker and online MSI [biological-mass-spectrometry-identification application]) in a multicenter manner. Ten European centers participated in the study, in which a total of 1511 yeast isolates were analyzed. The 10 centers prospectively performed the three protocols on approximately 150 yeast isolates each, and the corresponding spectra were then assessed against two reference spectra databases (MSI and Bruker), with appropriate thresholds. Three centers evaluated the impact of the targets. Scores were compared between the various combinations, and identification accuracy was assessed. The protocol omitting the extraction step was inappropriate for yeast identification, while the full extraction method yielded far better results. Rapid formic acid extraction yielded variable results depending on the target, database and threshold. Selecting the optimal extraction method in combination with the appropriate target, database and threshold may enable simple and accurate identification of clinically relevant yeast samples. Concerning the widely used polished-steel targets, the full extraction method still ensured better scores and better identification rates.

Background: Toxoplasma gondii is a parasite of worldwide importance but its burden in indigenous communities remains unclear. In French Guiana, atypical strains of T. gondii originating from a rainforest wild cycle have been linked to severe infections in humans. These cases of Amazonian Toxoplasmosis are sporadic and outbreaks are rarely described. We report on the investigation of an outbreak of acute toxoplasmosis in a remote Amerindian village. We discuss the causes and consequences of this emergence. Methods: Inhabitants from nine households were tested for T. gondii antibodies and parasite DNA by PCR when appropriate. Samples of water, cat feces and cat rectal swabs, soil and meat were tested for T. gondii DNA by PCR. Positive PCR samples with sufficient DNA amount were genotyped using 15 microsatellite markers. Results: Between early May and late June 2017, out of 54 tested inhabitants, 20 cases were serologically confirmed. A foetus infected at gestational week 10 died but other cases were mild. Four patients tested positive for parasite DNA and two identical strains belonging to an atypical genotype could be isolated from unrelated patients. While domestic cats had recently appeared in the vicinity, most families drank water from unsafe sources. Parasite DNA was recovered from one water sample and nine soil samples. Meat tested positive in three samples, including wild and industrialized meat. Conclusions: The recent domestication of cats probably enhanced the wild cycle of T. gondii in a village where fixed habitations along with unsafe sources of water paved the way for the emergence of human toxoplasmosis. The burden of T. gondii should be properly studied in other remote populations. Public health actions such as eradication of cats and epidemiological surveillance of acute toxoplasmosis should be implemented.

BACKGROUND: Toxoplasma gondii is one of the world's most common parasites. Primary infection of the mother during pregnancy can lead to transmission to the fetus with risks of brain and eye lesions, which may cause lifelong disabilities. France instituted a national program based on monthly retesting of susceptible pregnant women to reduce the number of severe cases through prompt antenatal and postnatal treatment and follow-up. OBJECTIVE: To evaluate the ability of the French prenatal retesting program to reduce the lifetime costs of congenital toxoplasmosis. METHODS: We measured and then compared the costs and benefits of screening vs. not screening using decision-tree modelling. It included direct and indirect costs to society of treatment and care, and the lifetime lost earnings of children and caregivers. A probabilistic sensitivity analysis was carried out. FINDINGS: Total lifetime costs per live born child identified as congenitally infected were estimated to be €444 for those identified through prenatal screening vs €656 for those who were not screened. Estimates were robust to changes in all costs of diagnosis, treatment, and sequelae. INTERPRETATION: Screening for the prevention of the congenital T. gondii infection in France is cost saving at €212 per birth. Compared with no screening, screening every pregnant woman in France for toxoplasmosis in 2020 would have saved the country €148 million in addition to reducing or eliminating the devastating physical and emotional suffering caused by T. gondii. Our findings reinforce the conclusions of other decision-analytic modelling of prenatal toxoplasmosis screening.

With increased interest in source attribution of foodborne pathogens, there is a need to sort and assess the applicability of currently available methods. Herewith we reviewed the most frequently applied methods for source attribution of foodborne diseases, discussing their main strengths and weaknesses to be considered when choosing the most appropriate methods based on the type, quality, and quantity of data available, the research questions to be addressed, and the (epidemiological and microbiological) characteristics of the pathogens in question. A variety of source attribution approaches have been applied in recent years. These methods can be defined as top-down, bottom-up, or combined. Top-down approaches assign the human cases back to their sources of infection based on epidemiological (e.g., outbreak data analysis, case-control/cohort studies, etc.), microbiological (i.e., microbial subtyping), or combined (e.g., the so-called 'source-assigned case-control study' design) methods. Methods based on microbial subtyping are further differentiable according to the modeling framework adopted as frequency-matching (e.g., the Dutch and Danish models) or population genetics (e.g., Asymmetric Island Models and STRUCTURE) models, relying on the modeling of either phenotyping or genotyping data of pathogen strains from human cases and putative sources. Conversely, bottom-up approaches like comparative exposure assessment start from the level of contamination (prevalence and concentration) of a given pathogen in each source, and then go upwards in the transmission chain incorporating factors related to human exposure to these sources and dose-response relationships. Other approaches are intervention studies, including 'natural experiments,' and expert elicitations. A number of methodological challenges concerning all these approaches are discussed. In absence of an universally agreed upon 'gold' standard, i.e., a single method that satisfies all situations and needs for all pathogens, combining different approaches or applying them in a comparative fashion seems to be a promising way forward.

West Nile virus (WNV) and Usutu virus (USUV) are two arthropod-borne viruses that circulate in mainland France. Assessing vector competence has only been conducted so far with mosquitoes from southern France while an increasingly active circulation of WNV and USUV has been reported in the last years. The main vectors are mosquitoes of the Culex genus and the common mosquito Culex pipiens. Here, we measure the vector competence of five mosquito species (Aedes rusticus, Aedes albopictus, Anopheles plumbeus, Culex pipiens and Culiseta longiareolata) present in northeastern France. Field-collected populations were exposed to artificial infectious blood meal containing WNV or USUV and examined at different days post-infection. We show that (i) Cx. pipiens transmitted WNV and USUV, (ii) Ae. rusticus only WNV, and (iii) unexpectedly, Ae. albopictus transmitted both WNV and USUV. Less surprising, An. plumbeus was not competent for both viruses. Combined with data on distribution and population dynamics, these assessments of vector competence will help in developing a risk map and implementing appropriate prevention and control measures.

Several species of Leishmania are responsible for leishmaniases in Thailand, although little is known about their transmission. Sergentomyia gemmea has been suspected several times to transmit Leishmania martiniquensis. Some captures carried out in Thailand and Lao People's Democratic Republic have emphasized the scarcity of Se. gemmea, comprising only 1% of the collected females. The sequencing of cytochrome B mtDNA of our specimens showed that our specimens are not grouped with other Se. gemmea previously deposited in GenBank. The latter are grouped with some Se. khawi and Se. hivernus that we processed in the present study. We suspect misidentifications and propose focusing on the most useful characters for identification of Se. gemmea based on the examination of type-specimens. The examination of the ascoids exhibiting anterior spurs is the most important one. However, we also describe Se. raynali n. sp. exhibiting comparable spurs but differing from Se. gemmea by its original cibarium. Finally, the vectorial role of Se. gemmea appears very questionable in the absence of new evidence.

One of the ways of human parasitic infection is the accidental ingestion of vegetables contaminated with parasites, which represents a major human health hazard. This non-exhaustive review aims to evaluate studies carried out on five types of vegetables (lettuce, parsley, coriander, carrot and radish) since 2000, particularly the methods used for recovery, concentration, detection and identification of protozoan parasites such as Toxoplasma gondii, Giardia duodenalis and Cryptosporidium spp., and the results of each work. Various studies have determined the presence of pathogenic parasites in fresh vegetables with different rates; this variation in rate depends particularly on the detection method used which is related to each parasite and each vegetable type. The variation in parasitic prevalence in food could be due to different factors such as the geographical location, the size of analysed samples and the methods used for parasite detection.

Background: Protozoan parasites such as Toxoplasma gondii, Giardia duodenalis, and Cryptosporidium spp., can be transmitted to humans via accidental consumption of contaminated water, fresh produce and foodstuffs. There is a lack of epidemiological data about these pathogens in Morocco. Hence the aim of this study, which is the determination of their prevalence in some leafy greens and root vegetables sold in Marrakech. Methods: A total of 132 vegetable samples including carrot, coriander, lettuce, parsley and radish were purchased monthly from three different markets in Marrakech from March 2017 to January 2018, pre-treated and subjected to microscopic and molecular analyses. Results: Of the 132 samples of vegetables analyzed by qPCR, the overall rate of protozoan was 21.21% (28/132); 22 samples were found to be contaminated with T. gondii, 6 with G. duodenalis, and none was positive for C. parvum/hominis. Whereas, modified Ziehl-Neelsen staining allowed the detection of Cryptosporidium spp. in 3% (4/132) of examined samples. Conclusion: This survey on the presence of protozoan parasites in fresh vegetables revealed that vegetables sold in Marrakech are contaminated by these protozoan parasites, as it showed that leafy green vegetables were more susceptible for parasitic contamination than root ones. Keywords: Fresh vegetables; protozoan parasites; Marrakech; qPCR.

BACKGROUND: Cases of Toxoplasma reactivation or more severe primary infection have been reported in patients receiving immunosuppressive (IS) treatment for autoimmune diseases (AID). The purpose of this study was to describe features of toxoplasmosis occurring in patients with AID treated by IS therapy, excluded HIV-positive and transplant patients. METHODS: A multicenter descriptive study was conducted using data from the French National Reference Center for Toxoplasmosis (NRCT) that received DNA extracts or strains isolated from patients, associated with clinical data. Other cases were retrieved through a questionnaire sent to all French parasitology and internal medicine departments. Furthermore, a systematic literature review was conducted. RESULTS: 61 cases were collected: 25 retrieved by the NRCT and by a call for observations and 36 from a literature review. Half of the cases were attributed to reactivation (50.9%), and most of cases (49.2%) were cerebral toxoplasmosis. The most common associated AID were rheumatoid arthritis (28%) and most frequent treatments were antimetabolites (44.3%). Corticosteroids were involved in 60.7% of cases. Patients had a favorable outcome (50.8%) but nine did not survive. For 12 cases, a successful Toxoplasma strain characterization suggested the possible role of this parasitic factor in ocular cases. CONCLUSION: Although this remains a rare condition, clinicians should be aware for the management of patients and for the choice of IS treatment.

Information on the viability of Toxoplasma gondii oocysts is crucial to establish the public health significance of this environmental transmission stage that can contaminate water and foods. Interest for molecular-based methods to assess viability is growing and the aim of our study was to assess, for the first time, a propidium monoazide (PMA)-qPCR approach to determine the viability of T. gondii oocysts. Untreated and heat-killed (99 °C, 5 min) oocysts were incubated with PMA, a photoreactive DNA binding dye, and analyzed by confocal microscopy and flow cytometry to characterize oocysts' dye permeability. Different PMA concentrations (50 to 150 μM), incubation temperatures (22, 37, and 45 °C), amplicon length, selected targeted gene, and dyes (PMA, PMAxx™) were evaluated to define optimal conditions to discriminate specifically viable oocysts by PMA-qPCR. In theory, PMA binding to DNA would inhibit PCR amplification in dead but not in viable oocysts. Incubation at 22 °C with 100 μM PMA coupled to qPCR targeting a 123-bp sequence of the 529-bp repeat element allowed the distinction between viable and heated oocysts. However, the reduction of viability following heating of oocysts at high temperature was slight and, contrarily to reverse transcriptase-qPCR, the qPCR signal was not totally suppressed in heated suspensions. Therefore, PMA-qPCR is able to assess the impact of heating on T. gondii oocysts' viability but underestimates the efficacy of this treatment. The relevance of this technique to evaluate the efficacy of other inactivation processes and assess exposure of humans to this pathogen requires further investigations.

), laminar/turbulent flow, shear stress, and electrostatic repulsion forces appear important to consider regarding oocyst release from biofilm. However, data analysis carried out during this review also revealed important gaps in biological interactions within biofilms, offering many perspectives for future work.

Phlebotomine sand flies are the main natural vectors of Leishmania, which cause visceral and tegumentary tropical diseases worldwide. However, their taxonomy and evolutionary history remain poorly studied. Indeed, as for many human disease vectors, their small size is a challenge for morphological and molecular works. Here, we successfully amplified unbiased copies of whole genome to sequence thousands of restriction-site associated DNA (RAD) markers from single specimens of phlebotomines. RAD markers were used to infer a fully resolved phylogeny of the subgenus Paraphlebotomus (11 species + 5 outgroups, 32 specimens). The subgenus was not recovered as monophyletic and we describe a new subgenus Artemievus subg. nov. Depaquit for Phlebotomus alexandri. We also confirm the validity of Ph. riouxi which is reinstated as valid species. Our analyses suggest that Paraphlebotomus sensu nov. originated ca 12.9-8.5 Ma and was possibly largely distributed from peri-Mediterranean to Irano-Turanian regions. Its biogeographical history can be summarized into three phases: i) a first split between Ph. riouxi + Ph. chabaudi and other species that may have resulted from the rise of the Saharan belt ca 8.5 Ma; ii) a Messinian vicariant event (7.3-5.3 Ma) during which the prolonged drought could have resulted in the divergence of main lineages; iii) a recent radiation event (3-2 Ma) that correspond to cycles of wet and dry periods in the Middle East and the East African subregions during the Pleistocene. Interestingly these cycles are also hypothetical drivers of the diversification of rodents, in the burrows of which Paraphlebotomus larvae develop. By meeting the challenge of sequencing pangenomics markers from single, minute phlebotomines, this work opens new avenues for improving our understanding of the epidemiology of leishmaniases and possibly other human diseases transmitted by arthropod vectors.

Diagnostic approaches based on PCR methods are increasingly used in the field of parasitology, particularly to detect Cryptosporidium. Consequently, many different PCR methods are available, both “in-house” and commercial methods. The aim of this study was to compare the performance of eight PCR methods, four “in-house” and four commercial methods, to detect Cryptosporidium species. On the same DNA extracts, performance was evaluated regarding the limit of detection for both C. parvum and C. hominis specificity and the ability to detect rare species implicated in human infection. Results showed variations in terms of performance. The best performance was observed with the FTD® Stool parasites method, which detected C. parvum and C. hominis with a limit of detection of 1 and 10 oocysts/gram of stool respectively; all rare species tested were detected (C. cuniculus, C. meleagridis, C. felis, C. chipmunk, and C. ubiquitum), and no cross-reaction was observed. In addition, no cross-reactivity was observed with other enteric pathogens. However, commercial methods were unable to differentiate Cryptosporidium species, and generally, we recommend testing each DNA extract in at least triplicate to optimize the limit of detection.