Seroprevalence and Risk Factors of Trichinella spiralis Infection in Blood Donors from Western Romania

Background and Objectives: Trichinellosis, a serious and sometimes fatal human disease, is a foodborne zoonotic disease with worldwide distribution caused by parasitic nematodes of the genus Trichinella. Humans are infected with Trichinella larvae through the ingestion of meat that has not been properly cooked. Romania reported most of the confirmed cases of trichinellosis among the EU countries. The aim of this cross-sectional study was to evaluate, for the first time, the seroprevalence and risk factors of Trichinella infection in blood donors from Western Romania. Materials and Methods: Serum samples of 1347 consecutive blood donors were investigated using an immunoenzymaticassay (ELISA) for the determination of specific IgG class antibodies against T.spiralis. A questionnaire interview was used to obtain information regarding the potential risk factors associated with T. spiralis infection. Mantel–Haenszel chi-squared test or the Fisher exact two-tailed test, as appropriate, were used for comparison between T. spiralis positive and T. spiralis negative blood donors. Student’s t-test was used to evaluate differences between means in studied groups and body mass index was calculated by dividing weight in kilograms by height in meters squared. Statistical analysis was performed using Epi Info Version 7.2 and Stata 16.1. Results: T. spiralis IgG antibodies were detected in 2.00% (27) of 1347 consecutive blood donors. Eating raw and/or undercooked meat, from pigs or wild boars, was found to be the main risk factor (p < 0.001). Strong alcoholic drink consumption was highly associated with T. spiralis infection (p = 0.009). Trichinella seroprevalence was higher among rural residents and males. Subjects identified as Trichinella seropositive were not previously diagnosed and have not been treated for Trichinella infection with any specific therapy. Conclusions: The demonstration of T. spiralis antibodies in healthy blood donors suggests that Trichinella infection may be detected in asymptomatic individuals that were not previously diagnosed with this zoonosis.

The Role of Ducks (Muscovy) and Catfish (Clarias Lazera) Meat in Transmitting Trichinella Spiralis Infection

Trichinellosis is a worldwide zoonotic food-borne disease that causes public health problems. The present study investigated the role of domestic ducks (Muscovy) and catfish (Clarias lazera) in transmitting Trichinella spiralis infection in Egypt. Ducks, fish, and rats were inoculated by high doses of Trichinella spiralis (T. Spiralis) larvae in naturally infected muscles of pigs and by free larvae extracted from artificial digestion. Both methods failed to develop an infection in ducks. No worms or cysts could be detected in ducks slaughtered 10, 25, and 45 days after inoculation. Moreover, there was no significant increase in the mean ELISA optical density (OD) value, compared to the control non-inoculated ducks. Inoculation of fish resulted in a significant increase in the mean ELISA OD value, compared to the control non-inoculated fish. This elevation was associated with the temporary detection of a few adult worms in the intestine of these fish which decreased with time till disappeared 45 days after inoculation but a non-significant increase was observed, compared to that obtained in the inoculated rats at the same stages. A large number of T. spiralis adult worms and cysts associated with a significant increase in the mean ELISA OD were recorded in the inoculated rats. Infection of rats (xenodiagnosis) by muscles collected from the inoculated ducks or fish failed to induce infection or elevation in the level of anti-T. spiralis antibodies (ATs-Ab) in their sera. In conclusion, Muscovy ducks and Clarias lazera could not be infected by T. spiralis in their muscles and the consumption of their meat could not transmit this infection to consumers in Egypt. However, proper cooking of meat is still necessary to avoid infection with other species.

Trichinella spiralis: Knockdown of gamma interferon inducible lysosomal thiol reductase (GILT) results in the reduction of worm burden

Trichinella spiralis is mammalian skeletal muscles parasite which may cause trichinellosis in animals and humans. Gamma interferon inducible lysosomal thiol reductase (GILT) is a widespread superfamily which plays key role in processing and presentation of MHC class II restricted antigen by catalyzing disulfide bond reduction. There are no reports about GILT in T. spiralis. In present study, GILT from T. spiralis (Tsp-GILT) was cloned, analyzed by multiple-sequence alignment, and predicted by 3D structure model. Recombinant Tsp-GILT (about 46 kDa) was efficiently expressed in Escherichia coli and thiol reductase activity suggested that in acidic environment the addition of a reducing agent is needed. Soaking method was used to knockdown expression of Tsp-GILT using small interference RNA (siRNA). Immunofluorescence assay confirmed the transformation of siRNA into muscle larva (ML) and new born larva (NBL). Quantitative real time-PCR (QRT-PCR) analysis revealed that transcription level of Tsp-GILT mRNA can be up-regulated by stimulation of mouse IFN-γ and down-regulated by siRNA2 in vitro. NBLs soaked with siRNA2 showed 32.3% reduction in the generation of MLs. MLs soaked with siRNA2 showed 26.2% reduction in the next generation of MLs, but no significant effect was observed on adult worms or NBLs. These findings concluded that GILT may play important roles in the development of T. spiralis parasite.

Trichinella Outbreaks on Pig Farms in Poland in 2012–2020

Trichinella nematodes continue to circulate in various hosts both in the domestic and sylvatic cycles. In the majority of countries in Europe, wild boars have been noticed as a primary source of Trichinella spp. infections in humans. However, in some regions, the meat of pigs containing Trichinella spp. larvae can still be a cause of trichinellosis. Therefore, in the present study, we aimed to determine and present actual data on the occurrence of Trichinella spp. on pig farms (Sus scrofa f. domestica) in Poland. In this study, over 194 million pigs, slaughtered for commercial and personal purposes between 2012 and 2020, were tested with a digestion method according to the official rules for Trichinella control. Positive results were noticed in 172 pigs which gives an overall prevalence of 0.000088%. On seven farms, rats (Rattus norvegicus) infected with Trichinella spp. were also discovered. The species identification showed pigs were infected with Trichinella spiralis on 26 farms, and on four farms pigs with Trichinella britovi infections were found. Therefore, it is important to constantly monitor pigs for the presence of these parasites, especially in view of the growing interest in organic meat originated from ecological farms.