Food and Waterborne Parasitology最新文献

An improved understanding of the environmental transmission of Taenia spp. is key to control of the parasite. Methods to detect and quantify Taenia eggs in different environmental matrices, including sludge and water, currently lack performance validation with regard to the recovery efficiency and process ease of use. Therefore, this study aimed to assess the recovery efficiency and process duration of commonly used methods for the detection of Taenia eggs in sludge and water samples. Ten detection methods for Taenia spp. eggs were selected from a systematic review. Sludge and water samples were spiked with a high dose of Taenia saginata eggs, i.e., around 200 eggs/g sludge and 50 eggs/ml water, and were tested using five methods each. The two methods with the highest egg recovery efficiencies were selected per matrix for assessment with a lower spiking dose, i.e., 4 eggs/g sludge and 1 egg/ml water. Each time five replicates were used. Recovery efficiency was defined as the proportion of the number of eggs recovered to the total number of eggs spiked. Using the high spiking dose, all samples tested positive for all the methods. The mean egg recovery efficiency varied from 4% to 69% for sludge samples and from 3% to 68% for water samples. Using the lower spiking dose, one of the methods performed on sludge samples was able to detect all replicates, whereas only one replicate was positive using the other method. For water, all low dose samples tested positive using both methods. In conclusion, most methods performed inadequately in recovering Taenia eggs from sludge and water, with half of the methods performed on the high dose samples having a mean egg recovery efficiency of approximately 10% or less. The assessed recovery methods were generally time-consuming and labourious. A more thorough validation of existing recovery methods and improvement of method protocols to increase recovery efficiency is thus urgently needed.

Nematodes of the genus Trichinella are important zoonotic parasites present throughout Romania. This study aimed to assess the status of Trichinella species in wild animals in Romania over the past 30 years. A literature review of original studies concerning the only two species (out of the four in Europe) of Trichinella (T. spiralis and T. britovi) confirmed in wildlife from Romania was conducted and corroborated with the results of our original research concerning the topic. This review article has shown that, in Romania, European minks were infected with T. spiralis, while wolves, European wild cats, Eurasian lynx, golden jackals, stone marten, and European badgers were infected with T. britovi, respectively. Both Trichinella species have been identified in foxes, bears, wild boars, and ermines, but mixed infections have been found only in European polecats. Trichinella infection is still significantly present in Romania, infecting several wild omnivorous and carnivorous species in an equal manner, with different prevalence rates over the years. Regarding the spatial distribution of T. spiralis and T. britovi in Romania, both species can be found all over the country, but in wild animals, T. britovi is the most prevalent.

To present the situation of human trichinellosis in Southeast Asia in the last 20th years we analyzed outbreak data and seroprevalence studies from 2001 to 2021 for this region. We queried PubMed (https://pubmed.ncbi.nlm.nih.gov) using keywords “Trichinella”, “human” and “Southeast Asia”. In addition, we described Trichinella species circulating in this region.

In Southeast Asia, in communities eating pork, several cultural factors play important roles in the transmission of Trichinella to humans. The seroprevalences of Trichinella infection in humans are known for Laos and Vietnam to be 0–10.5% in some villages. Also, in Cambodia, Laos, Malaysia, Thailand and Vietnam relatively few human outbreaks (13) and cases (1604) have been recorded during the last 21st years. Their associated mortality rates were low (0.75%). Trichinella spiralis and T. papuae were transmitted after consumption of raw or undercooked pork from domesticated and wild pigs. T. papuae transmission was related to consumption of wild boar. In this region, trichinellosis was frequently subclinical and clinical or severe cases were sporadic and occurred more in male patients. Nevertheless, it is likely that trichinellosis is widely under-diagnosed and is an endemic disease.

This Special Issue in Food and Waterborne Parasitology consists of six articles derived from presentations at the 13th European Multicolloquium of Parasitology (EMOP), that was held in Belgrade, Serbia in October 2021. Within the broad scope of parasitology presented at EMOP 2020/2021, the focus of several sessions, seminars, and presentations was on foodborne and waterborne parasites, with different aspects concerned with Cryptosporidium, Toxoplasma, Trichinella, and Opisthorchis all featuring. Although only a few manuscripts on foodborne and waterborne parasites are presented in this SI, the wide-ranging scope of the articles and, more broadly, of the presentations at EMOP 2020/2021, suggests that the topic of parasites transmitted by food and/or water remains of interest in the European parasitology community. We believe this is likely to be the case for years to come, and the topic is likely to feature prominently in the next (14th) EMOP, scheduled to be held in Poland in 2024. This interest, along with some obvious gaps in the articles on foodborne and waterborne parasites of both European and global importance (such as tapeworms, particularly Echinococcus spp. and Taenia solium), suggests to us that another SI on the subject could be of value as an outcome of the 14th EMOP.

Ascarid infections constitute a major concern for both human and animal health risk assessment. Although being effectively transmitted by soil, water and contaminated food, reliable detection of ascarid eggs in environmental media often remains challenging. However, contamination of the environment with ascarid ova has gained more attention as a decisive part of proper risk assessment in recent years. Due to various factors, such as sample matrices, dissociation detergents and flotation solutions, defined and standardised protocols for the isolation of eggs from complex environmental matrices are difficult to establish and therefore limited. Thus, this study reviews common techniques used for the recovery of ascarid eggs from environmental media with special emphasis on sampling strategies, purification procedures and microscopic as well as molecular detection of egg contamination. Despite various advancements, mainly in the field of molecular methods leading to more reliable and sensitive detection, it can be concluded that there is still a need for unified guidelines for sampling and recovery of ascarid eggs derived from complex environmental matrices.

Toxoplasma gondii and Neospora caninum infections are important causes of abortion in ruminants. Besides, meat from T. gondii infected animals represent a major infection source for humans. The occurrence of these protozoan parasites in Switzerland was investigated both, in a nationwide cross-sectional serological survey, and by molecular methods in aborted sheep and goat foetuses. A total of 653 sheep from 143 farms and 748 goats from 164 farms were tested by commercial ELISAs and inconclusive results were defined by immunoblot. Besides, a risk factor analysis for seropositivity was performed. The observed seroprevalences for T. gondii in sheep and goats were 66.3% and 50.5% at the animal level, and 90.9% and 81.1% at the farm level, respectively. For N. caninum, the detected seroprevalences in sheep and goats were 0.8% and 0.9% at the animal level, and 2.8% and 1.8% at the farm level, respectively. Older small ruminants, and sheep (vs. goats) had a higher risk of being seropositive to T. gondii. Alpine grazing in summer was identified as a protective factor for seropositivity to T. gondii in both animal species. Toxoplasma gondii and N. caninum DNA were detected in 6.1% and 2.4% (n = 82), and in 6.8% and 1.4% (n = 73) of the tested ovine and caprine foetuses, respectively. These results suggest the involvement of these parasites in abortions and reveal a high prevalence of T. gondii and lower prevalence of N. caninum infections in small ruminants in Switzerland. They also suggest that consumption of undercooked meat from T. gondii infected sheep and goats may represent a risk for public health.

Cryptosporidium is a widely distributed food and water-borne enteric protozoan that affects a wide range of vertebrates, resulting in life-threatening consequences, particularly in immunocompromised hosts. The lack of effective anti-cryptosporidial drugs may be related to the parasite's unique intestinal location, plus the lack of studies on the process by which the protozoan is able to impair intestinal cellular function. The present work aimed to assess the effect of clofazimine (CFZ), an FDA-approved drug for the treatment of leprosy, as an anti-cryptosporidial drug, using transmission electron microscopy (TEM) and an immunocompromised mouse model. The affected intestinal mucosa with parasitic stages in the infected non-treated group showed signs of severe cellular degeneration, including the loss of tight junctions, deformed and damaged microvilli and irregularly distributed nuclei with a severely vacuolated cytoplasm. Comparatively, nitazoxanide (NTZ) monotherapy showed the lowest efficacy as the drug was associated with the lowest rate of oocyst shedding. In addition, NTZ treatment failed to achieve the return of complete cellular function; abnormalities were evident in the microvilli, cytoplasmic organelles and nuclear features. Clofazimine demonstrated an improvement of the mucosal cellular components, including mitochondria and significantly reduced oocyst shedding. Combined treatment with low-dose CFZ and half-dose NTZ resulted in a significant improvement in the enterocyte cellular structures with an absence of intracellular parasitic stages. These results indicate that CFZ, a safe and readily prescribed drug, effectively reduces cryptosporidiosis when used in combination with only half the dose of NTZ. Used in combination, these drugs were shown to be efficient in regaining intestinal cellular activity following Cryptosporidium-induced functional damage in an immunocompromised mouse model.

The food-borne trematode Opisthorchis felineus colonizes bile ducts of the liver of fish-eating mammals including humans. Among chronically infected individuals, this opisthorchiasis involves hepatobiliary problems, including chronic inflammation, periductal fibrosis, biliary intraepithelial neoplasia, and even cholangiocarcinoma. Despite numerous studies at the pathomorphological level, the systemic response and cellular pathogenesis of these disorders are not well studied.

To conduct in-depth research and to gain insights into the mechanism by which O. felineus infection causes precancerous liver lesions, we (i) applied a next-generation-sequencing–based technology (high-throughput mRNA sequencing) to identify differentially expressed genes in the liver of golden hamsters infected with O. felineus at 1 and 3 months postinfection and (ii) verified the most pronounced changes in gene expression by western blotting and immunohistochemistry.

A total of 2151 genes were found to be differentially expressed between uninfected and infected hamsters (“infection” factor), whereas 371 genes were differentially expressed when we analyzed “time × infection” interaction. Cluster analysis revealed that sets of activated genes of cellular pathways were different between acute (1 month postinfection) and chronic (3 months postinfection) opisthorchiasis. This enriched KEGG pathways were “Cell adhesion molecules”, “Hippo signaling”, “ECM-receptor interaction”, “Cell cycle”, “TGF-beta”, and “P53 signaling”. Moreover, epithelial–mesenchymal transition was the most enriched (q-value = 2.2E-07) MSigDB hallmark in the set of differentially expressed genes of all O. felineus–infected animals. Transcriptomic data were supported by the results of western blotting and immunohistochemistry revealing the upregulation of vimentin, N-cadherin, and α-smooth muscle actin postinfection.

Our data expand knowledge about global changes in gene expression in the O. felineus–infected host liver and contribute to understanding the biliary neoplasia associated with the liver fluke infection.

Toxocara canis and T. cati are zoonotic roundworm parasites of dogs, cats and foxes. These definitive hosts pass eggs in their faeces, which contaminate the environment and can subsequently be ingested via soil or contaminated vegetables. In humans, infection with Toxocara can have serious health implications. This proof-of-concept study aimed to investigate the presence of Toxocara spp. eggs on ‘ready-to-eat’ vegetables (lettuce, spinach, spring onion and celery) sampled from community gardens in southern England. The contamination of vegetables with Toxocara eggs has never been investigated in the UK before, and more widely, this is the first time vegetables grown in community gardens in Europe have been assessed for Toxocara egg contamination. Sixteen community gardens participated in the study, providing 82 vegetable samples fit for analysis. Study participants also completed an anonymous questionnaire on observed visits to the sites by definitive hosts of Toxocara. Comparison of egg recovery methods was performed using lettuce samples spiked with a series of Toxocara spp. egg concentrations, with sedimentation and centrifugal concentration retrieving the highest number of eggs. A sample (100 g) of each vegetable type obtained from participating community gardens was tested for the presence of Toxocara eggs using the optimised method. Two lettuce samples tested positive for Toxocara spp. eggs, giving a prevalence of 2.4% (95% CI =1.3–3.5%) for vegetable samples overall, and 6.5% (95% CI = 4.7–8.3%; n = 31) specifically for lettuce. Questionnaire data revealed that foxes, cats and dogs frequently visited the community gardens in the study, with 88% (68/77) of respondents reporting seeing a definitive host species or the faeces of a definitive host at their site. This proof-of-concept study showed for the first time the presence of Toxocara spp. eggs on vegetables grown in the UK, as well as within the soil where these vegetables originated, and highlights biosecurity and zoonotic risks in community gardens. This study establishes a method for assessment of Toxocara spp. eggs on vegetable produce and paves the way for larger-scale investigations of Toxocara spp. egg contamination on field-grown vegetables.