Food and Waterborne Parasitology最新文献

Understanding the ecological factors that drive the spatial patterns of parasites transmission is essential to predict their distribution under global change and to direct proactive surveillance efforts. Here, we systematically reviewed the literature to assess the main ecological drivers responsible for the spatial distribution and transmission of the zoonotic cestode Echinococcus multilocularis, the aetiological agent of alveolar echinococcosis, focusing on wild hosts. The 23 retrieved studies suggested that the dispersal of definitive hosts, climatic and biotic factors (distribution of intermediate hosts, composition of host communities) shape continental-scale distribution patterns of E. multilocularis, whereas the relative importance of climate and land cover in driving E. multilocularis distribution at a smaller (country/regional) scale varies with the geographic area considered. At a local scale, two additional factors contribute to determine the distribution of micro-foci of transmission: the trophic relationships between carnivores definitive hosts and small mammals intermediate hosts, and the defecation and marking behaviour of definitive hosts.

Taenia solium porcine cysticercosis (PCC) is widespread in many low- and middle-income countries (LMICs) where free-range pig rearing is common and hygienic standards are subpar. A cross-sectional survey was conducted in 42 villages between June and September 2019 (14 in Songwe district, southwest Tanzania, and 28 in Kongwa district, central Tanzania). Using a commercial Ag-ELISA kit (apDia, Belgium), circulating antigens of Taenia spp in pig serum were identified and used to calculate the PCC seroprevalence. The study recruited 692 randomly selected households, sampling one pig per household. The relationship between each risk factor and the seroprevalence of PCC at the household and village levels was analysed using mixed logistic regression models. The findings showed that approximately 28% of the pigs were reared in free-range settings, the proportion of households with latrines across the districts was 92%. Twenty-seven percent of households with latrines had water and soap available for hand washing. Sixty-seven (9.7%) tested positive for PCC based on Ag-ELISA. The overall seroprevalence in Kongwa and Songwe districts was 7.3% and 14.0% respectively. In addition, the overall village Ag-ELISA positivity was 9.3%, with an interquartile range (IQR) of 4.6% – 14.1%. Increasing the age of the pig (OR = 3.13 95% CI = 1.48 – 6.60; p = 0.003), pig originating from outside the household (OR = 0.5 95% CI = 0.25 – 0.99; p = 0.05), and pigs kept in a household that practised deworming (OR = 2.23 95% CI = 1.08 – 4.61; p = 0.03) were important risk factors associated with PCC positivity. Therefore, the high seroprevalence of PCC, up to 14%, calls for rapid and effective control actions such as vaccination and treatment of pigs against PCC, and public health education emphasises on indoor pig rearing, hygienic practices and regular use of latrines. Our findings also point to a potential danger of Taenia. spp infection indicating the possibility of people carrying the adult parasite Taenia solium not only in the rural communities of Kongwa and Songwe districts but also in the urban areas of Tanzania, where pigs from these areas are transported for consumption. To develop effective management measures, further research on taeniasis and cysticercosis in the human population is required.

Diphyllobothriosis is an infectious disease caused by the consumption of raw freshwater or marine fish containing larvae of broad tapeworms (Diphyllobothriidae). In the present study, we critically reviewed all cases of human diphyllobothriosis reported from Taiwan, including unpublished reports from hospitals in Taipei. Genotyping based on mitochondrial DNA marker (cox1) confirmed that two of the recent cases were caused by Dibothriocephalus nihonkaiensis, which is not native to Taiwan and was probably imported with Pacific salmon infected with larvae of D. nihonkaiensis. The causative species previously reported in Taiwan could not be definitively confirmed. However, considering the distribution of Dibothriocephalus latus, which is not endemic in Taiwan, past cases diagnosed as D. latus are questionable.

The protozoan parasites Cryptosporidium parvum, Cyclospora cayetanensis, and Toxoplasma gondii are major causes of waterborne and foodborne diseases worldwide. The assessment of their removal or inactivation during water treatment and food processing remains challenging, partly because research on these parasites is hindered by various economical, ethical, methodological, and biological constraints. To address public health concerns and gain new knowledge, researchers are increasingly seeking alternatives to the use of such pathogenic parasites. Over the past few decades, several non-pathogenic microorganisms and manufactured microparticles have been evaluated as potential surrogates of waterborne and foodborne protozoan parasites. Here, we review the surrogates that have been reported for C. parvum, C. cayetanensis, and T. gondii oocysts, and discuss their use and relevance to assess the transport, removal, and inactivation of these parasites in food and water matrices. Biological surrogates including non-human pathogenic Eimeria parasites, microorganisms found in water sources (anaerobic and aerobic spore-forming bacteria, algae), and non-biological surrogates (i.e. manufactured microparticles) have been identified. We emphasize that such surrogates have to be carefully selected and implemented depending on the parasite and the targeted application. Eimeria oocysts appear as promising surrogates to investigate in the future the pathogenic coccidian parasites C. cayetanensis and T. gondii that are the most challenging to work with.

Human cysticercosis is a life-threatening zoonotic disease caused by infection with larvae (cysticerci) of the pork tapeworm, Taenia solium. This can affect the nervous system causing chronic headache and intracranial hypertension, potentially leading to epileptic seizures and paralysis. The disease is found in developing countries, especially in Southeast and South Asia, Sub-Saharan Africa, and Central and South America where porcine cysticercosis is endemic and people have a habit of eating undercooked pork. An immunochromatography-based test (ICT) kit, using T. solium cyst fluid as antigen, was manufactured to detect anti-T. solium IgG antibodies in human serum. To evaluate the kit, we used 187 serum samples including 24 from proven/confirmed cysticercosis cases, 133 from cases with other parasitosis and 30 healthy controls. Diagnostic efficiencies were calculated. The sensitivity, specificity, and accuracy were 83.3%, 92.0%, and 90.9%, respectively. Moreover, the ICT was positive before treatment but became negative after treatment, implying that this kit is also useful for follow-up monitoring post-treatment. In conclusion, we have successfully developed and present preliminary evaluation of an easy-to-handle rapid diagnostic tool for human cysticercosis in the form of an ICT platform using as antigen fluid from T. solium cysticerci.

Intestinal parasites continue to pose a significant threat to human health worldwide, particularly among children. Contaminated water and soil serve as major transmission vehicles for these parasites and intestinal protists are among the most prevalent parasites in both developed and developing nations. Traditionally, parasites have been studied using human or animal fecal samples, while studying them in environmental samples has been challenging due to technical limitations. However, advancements in Next-Generation Sequencing (NGS) and bioinformatic approaches now enable the detection of parasite DNA in environmental samples. In this study, we applied a metataxonomic and phylogenetic strategy to detect and classify DNA of protists present in sewage sludge from two major cities in Colombia: Medellin and Cali. We successfully detected several human pathogenic parasites including Giardia intestinalis, Entamoeba histolytica, and Blastocystis sp., among other protists, in all sludge samples examined. We also investigated the entry and exit of parasite DNA from the San Fernando wastewater treatment plant (WWTP). We observed a higher number of parasite DNA sequences in the plant's influent wastewater, but we also detected the discharge of DNA from pathogenic parasites in both effluent waters and biosolids.

Gnathostoma is a parasitic nematode that can infect a wide range of animal species, but human populations have become accidental hosts because of their habit of eating raw or undercooked meat from a wide variety of intermediate hosts. While gnathostomiasis is considered an endemic disease, cases of human gnathostomiasis have been increasing over time, most notably in nonendemic areas. There are several complexities to this parasitic disease, and this review provides an update on human gnathostomiasis, including the life cycle, diagnosis, treatment, and treatment strategies used to combat drug resistance. Even now, a definitive diagnosis of gnathostomiasis is still challenging because it is difficult to isolate larvae for parasitological confirmation. Another reason is the varying clinical symptoms recorded in reported cases. Clinical cases can be confirmed by immunodiagnosis. For Gnathosotoma spinigerum, the detection of IgG against a specific antigenic band with a molecular weight of 24 kDa from G. spinigerum advanced third-stage larvae (aL3), while for other species of Gnathostoma including G. binucleatum, the 33-kDa antigen protein is being used. This review also discusses cases of recurrence of gnathostomiasis and resistance mechanisms to two effective chemotherapeutics (albendazole and ivermectin) used against gnathostomiasis. This is significant, especially when planning strategies to combat anthelmintic resistance. Lastly, while no new chemotherapeutics against gnathostomiasis have been made available, we describe the management of recurrent gnathostomiasis using albendazole and ivermectin combinations or extensions of drug treatment plans.

In this study, the presence of Acanthamoeba spp., Blastocystis sp., Cryptosporidium spp., Cyclospora cayetanensis, Entamoeba histolytica, Giardia sp., Toxoplasma gondii and Vermamoeba vermiformis was assessed in organic leafy green vegetables (lettuce, spinach, cabbage) and fruits (strawberry), which are usually consumed raw. A total of 110 organic samples were collected in Valencia (Spain). Protozoa were concentrated before detection by immunofluorescence (Cryptosporidium spp. and Giardia sp.) or real-time qPCR (Acanthamoeba spp., Blastocystis sp., C. cayetanensis, E. histolytica, T. gondii and V. vermiformis). The most abundant protozoa in organic vegetables and berry fruits were Acanthamoeba (65.5%), followed by T. gondii (37.2%), V. vermiformis (17.3%), C. cayetanensis (12.7%), Cryptosporidium spp. (6.8%), Blastocystis sp. (1.8%) and Giardia sp. (1.7%). E. histolytica was not found in any of the organic samples. Thus, results showed that consumers can be exposed to protozoan parasites by consuming organic vegetables and berry fruits. This is the first report in Spain describing the presence of the protozoan pathogens Acanthamoeba spp., Blastocystis sp., C. cayetanensis, T. gondii and V. vermiformis, Cryptosporidium spp. and Giardia sp. in organic fresh produce. The results of this research will help determine the risk of foodborne protozoan parasites on organic leafy greens and strawberries that are available at local markets.