Trichinellosis is a re-emerging worldwide foodborne zoonosis. Oxidative stress is one of the most common detrimental effects caused by trichinellosis. In addition, Trichinella infection poses an infinite and major challenge to the host’s immune system. Resistance and side effects limit the efficiency of the existing anti-trichinella medication. Given that concern, this work aimed to investigate the anti-helminthic, antioxidant, anti-inflammatory and immunomodulatory effects of resveratrol and zinc during both phases of Trichinella spiralis infection. Sixty-four Swiss albino mice were divided into four equal groups: non-infected control, infected control, infected and treated with resveratrol, and infected and treated with zinc. Animals were sacrificed on the 7th and 35th days post-infection for intestinal and muscular phase assessments. Drug efficacy was assessed by biochemical, parasitological, histopathological, immunological, and immunohistochemical assays. Resveratrol and zinc can be promising antiparasitic, antioxidant, anti-inflammatory, and immunomodulatory agents, as evidenced by the significant decrease in parasite burden, the significant improvement of liver and kidney function parameters, the increase in total antioxidant capacity (TAC), the reduction of malondialdehyde (MDA) level, the increase in nuclear factor (erythroid-derived 2)-like-2 factor expression, and the improvement in histopathological findings. Moreover, both drugs enhanced the immune system and restored the disturbed immune balance by increasing the interleukin 12 (IL-12) level. In conclusion, resveratrol and zinc provide protection for the host against oxidative harm and the detrimental effects produced by the host’s defense response during Trichinella spiralis infection, making them promising natural alternatives for the treatment of trichinellosis.

Trichinellosis is a global food-borne disease caused by viviparous parasitic nematodes of the genus Trichinella. Due to the lack of effective, safe therapy and the documented adverse effects of traditional therapy, this study aimed to evaluate the therapeutic effect of acetazolamide-loaded silver nanoparticles (AgNPs) on murine trichinellosis. Fifty male Swiss albino mice were divided into five groups of ten mice each: Group I, normal control group; Group II, infected with T. spiralis and not treated; Group III, infected and given AgNPs; Group IV, infected and treated with acetazolamide; and Group V, infected and treated with acetazolamide-loaded AgNPs. Mice were infected orally with 250 larvae. The efficacy was assessed by counting T. spiralis adults and larvae, measuring serum total antioxidant capacity, and observing the histopathological and ultrastructural alterations. Acetazolamide-loaded AgNPs treatment exhibited the highest percentage of reduction (84.72% and 80.74%) for the intestinal adults and the muscular larvae of T. spiralis-infected animals, respectively. Furthermore, during the intestinal and muscular phases, the serum of the same group had the best free-radical scavenging capacity (antioxidant capacity), which reduced tissue damage induced by oxidative stress. Histopathologically, the normal intestinal and muscular architecture was restored in the group treated with acetazolamide-loaded AgNPs, in addition to the reduced inflammatory infiltrate that alleviated inflammation compared to infected animals. Our results confirmed the marked destruction of the ultrastructural features of T. spiralis adults and larvae. Acetazolamide-loaded AgNPs are a promising therapy against T. spiralis infection.

Trichinellosis is a serious foodborne zoonosis. It poses a serious risk to public health worldwide. Early serological diagnosis of trichinellosis is influenced by an immunological ‘silent’ phase following infection. This highlights the necessity for developing sensitive diagnostic approaches to be employed when antibodies cannot be detected. In this work, the validity of traditional ELISA, Nano-ELISA and real time polymerase chain reaction (PCR) were evaluated in early diagnosis of Trichinella spiralis. Swiss albino mice were orally infected with 100 and 300 muscle larvae/mouse. Mice were sacrificed 4, 6, 8, 10, 15, and 28 days post-infection (dpi). Blood samples were tested for circulating antigen by traditional ELISA and Nano-ELISA using anti-rabbit polyclonal IgG conjugated with AgNPs and for Rep gene by SYBR green real-time PCR. Rep gene detection by SYBR green real-time PCR could detect T. spiralis with 100% sensitivity in the mild infection group at 8 dpi, while in the severe infection group it reached 100% sensitivity at 4 dpi. Nano-ELISA could detect T. spiralis circulating antigen from 4 dpi in both mild and severe infection and reached 100% sensitivity at 8 dpi and 6 dpi in mild and severe infection, respectively. However, traditional ELISA could detect T. spiralis circulating antigen from 6 dpi and reached maximum sensitivity at 15 dpi in the mild infection group, while in the severe infection group detection began at 4 dpi and reached 100% sensitivity at 8 dpi. Nano-ELISA and real time PCR, using Rep gene, are useful tools for the detection of early T. spiralis infection even in its mild infection state.

Currently, no effective treatment is available for trichinellosis, a zoonotic parasitic disease caused by infection with the genus Trichinella. Kaempferol (KPF), a dietary flavonoid, has been documented to have anti-parasitic effects and various medicinal uses. Thus, this study aimed to investigate the efficacy of KPF in preventing and treating the intestinal and muscular phases of trichinellosis in mice compared with albendazole (ABZ). To achieve this, mice were divided into six groups: negative control; positive control; KPF prophylaxis; KPF treatment; ABZ treatment; and a combination of ABZ and KPF. Parasitological, histopathological and immunohistochemical evaluations were conducted to assess the effectiveness of the treatments. The parasitological assessment involved counting small intestinal adult worms and encysted muscle larvae. Additionally, the histopathological evaluation used the haematoxylin and eosin staining method for intestinal and muscular sections and picrosirius red stain for muscular sections. Moreover, the immunohistochemical expression of the intestinal NOD-like receptor-pyrin domain containing 3 (NLRP3) was evaluated. The group treated with combined drugs demonstrated a statistically significant reduction in the count of adults and encysted larvae (P < 0.05), a remarkable improvement in the inflammation of the intestines and muscles and a decrease in the thickness of the larvae's capsular layer. Additionally, the highest reduction in NLRP3 expression was observed in this group. Based on this study, KPF shows promise as an anti-trichinellosis medication that, when taken with ABZ, has a synergistic impact by modulating inflammation and larval capsule formation.

In Serbia, in most cases, small family outbreaks of trichinellosis occur due to the consumption of untested infected meat from domestic pigs that are raised and slaughtered in the backyards of small individual farms. The aim of this study is to present data regarding 24 patients involved in two outbreaks that occurred in two neighbouring districts in Serbia during a closely related period of time in August 2014. The source of infection in the first outbreak was undercooked pork, while raw pork sausages caused the second outbreak. Meat samples and sausages were Trichinella spp. positive by artificial digestion. With the aim to obtain a second opinion and validate the serological findings discovered at the Public Health Institute Nis, all samples were sent to the National Reference Laboratory for Trichinellosis, INEP. Serodiagnosis showed that 21 persons were positive (87.5%) and three (12.5%) were negative for anti-Trichinella antibodies, while 15 patients fulfilled the trichinellosis case definition. Western blot analysis (using an epitope unique for the muscle larvae stage of the Trichinella genus) confirmed the diagnosis of trichinellosis in five patients. Six patients also had specific antibodies against Toxocara canis (T. canis). Due to the fact that in endemic foci in Serbia there is the presence of Trichinella spiralis and T. canis and that these two infections could be asymptomatic, we consider that trichinellosis cases were irrefutably proven. The dilemma about the existence of co-infection with T. canis remained open due to the lack of clinical findings.

Our work aimed to evaluate the possible effect of Annona muricata (Graviola) leaf extract on Trichinella spiralis in in vitro and in vivo studies. Trichinella spiralis worms were isolated from infected mice and transferred to three culture media – group I (with no drugs), group II (contained Graviola) and group III (contained albendazole) – then they were examined using the electron microscope. In the in vivo study, mice were divided into five groups: GI (infected untreated), GII (prophylactically treated with Graviola for seven days before infection), GIII (infected and treated with Graviola), GIV (infected and treated with albendazole) and GV (infected and treated with a combination of Graviola plus albendazole in half doses). Drug effects were assessed by adults and larvae load beside the histopathological small intestinal and muscular changes. A significant reduction of adult and larval counts occurred in treated groups in comparison to the control group. Histopathologically, marked improvement in the small intestinal and muscular changes was observed in treated groups. Also, massive destruction of the cultured adults’ cuticle was detected in both drugs. This study revealed that Graviola leaves have potential activity against trichinellosis, especially in combination with albendazole, and could serve as an adjuvant to anti-trichinellosis drug therapy.

The present work aimed at studying the efficacy of mebendazole (MBZ) compared to artemisinin (ART) for the treatment of trichinellosis at various phases of infection. Seventy Swiss albino mice were orally infected by 300 Trichinella spiralis (T. spiralis) larvae. Mice were divided into infected untreated control group and infected groups treated with 50 mg kg−1 MBZ and 300 mg kg−1 ART for three and five consecutive days, respectively, at the enteral phase [2–4 days post infection (PI)], invasive phase (10–12 days PI) and encapsulated phase (28–30 days PI). All mice were sacrificed 35–42 days PI. MBZ and ART revealed a significant decrease in mean larval counts and increase of larval per cent reduction (LR %) when treatment was initiated during the enteral phase compared to the other phases. MBZ showed significantly higher LR % (99.7, 83.95 and 89.65%) than ART (80.58, 67.0 and 79.2%) when administered at the three infection phases. Histopathological study showed a decrease in the number of encysted larvae, their surrounding cellular infiltrates and increased regenerative muscles in all treated mice. In conclusion, ART possesses a substantial anthelmintic activity against T. spiralis infection in mice both at the enteral and encapsulated phases, yet, significantly lower than MBZ.

The hygiene hypothesis posits that the decreased incidence of parasitic infection in developed countries may underlie an increased prevalence of allergic and autoimmune diseases in these countries. As unique inflammation modulator of intracellular parasitism, Trichinella spiralis, or its excretory–secretory (ES) product, shows improved responses to allergies, autoimmune diseases, inflammatory bowel disease, type 1 diabetes, rheumatic arthritis and autoimmune encephalomyelitis by exerting immunomodulatory effects on both innate and adaptive immune cells in animal models. Research has shown that T. spiralis differs from other helminths in manipulation of the host immune response not only by well-known characteristics of its life cycle, but also by its inflammation modulation pathway. How the parasite achieves inflammation modulation has not been fully elucidated yet. This review will generalize the mechanism and focuses on ES immunomodulatory molecules of T. spiralis that may be important for developing new therapeutics for inflammatory disorders.

Trichinellosis is a serious food-borne zoonotic infection of cosmopolitan distribution. Currently, treatment for trichinellosis is far from ideal. Given the important role of oxidative stress and immune-mediated inflammation in the pathogenesis of trichinellosis, this study was designed to evaluate the possible protective effects of resveratrol (RSV) during the intestinal and muscular phases of Trichinella spiralis infection in mice. The oral administration of RSV at a dose of 20 mg/kg once daily for two weeks resulted in significant reductions in both adult and larval counts; significant improvements in the redox status of the small intestine and muscles; a significant reduction in interleukin 4, pentraxin 3 and vascular endothelial growth factor expression; and the mitigation of intestinal and muscular inflammation. In conclusion, this study identifies RSV as a promising agent for the treatment of experimental trichinellosis, and more studies in experimental animals and humans are worth consideration.

Immunomodulation by molecules from Trichinella spiralis (T. spiralis) has been widely reported. Glutathione-S-transferase (GST) is a major immune-modulator of the family of detoxification enzymes. Dendritic cells (DCs) are an important target for the regulation of the immune response by T. spiralis. In this study, the recombinant GST of T. spiralis (rTs-GST) was expressed and purified. rTs-GST induced low CD40 expression and moderate CD80, CD86 and MHC-II expressions and inhibited the increase of CD40, CD80 and CD86 on DCs induced by LPS. We showed that rTs-GST decreased the LPS-induced elevated level of pro-inflammatory cytokines of DCs and enhanced the level of regulatory cytokines IL-10 and TGF-β. Furthermore, co-culture of DCs and CD4+ T cells demonstrated that rTs-GST-treated DCs suppressed the proliferation of OVA-specific CD4+ T cells and increased the population of regulatory T cells (Tregs). rTs-GST-treated DCs induced a higher level of IL-4, IL-10 and TGF-β, but inhibited the level of IFN-γ. This indicates that rTs-GST-pulsed DCs induce both Th2-type responses and Tregs. These findings contribute to the current understanding of the immunomodulation of Ts-GST on cellular response and immunomodulation of T. spiralis.

Human infections with Trichinella spiralis and respiratory syncytial virus (RSV) are common, as T. spiralis infections are re-emerging in various parts of the world and RSV infections remain a threat for infants. Yet, studies investigating the relationship pertaining to the two are severely lacking. In particular, immune response induction via RSV and T. spiralis remain largely elusive. Here, we investigated the resistance against T. spiralis infection induced upon primary infection with RSV. RSV, notorious for causing severe inflammatory reaction in the lungs, were intranasally infected, followed with a T. spiralis infection in mice. Our results revealed that primary RSV infection in mice significantly raised T. spiralis-specific and total IgE, IgG and its subclass antibody responses upon T. spiralis challenge infection (RSV-Ts). Blood eosinophil levels were decreased in RSV-Ts, accompanied with significant increase in both Th1 and Th2 cytokines. Antibodies generated against RSV in RSV-infected mice were found to react with T. spiralis excretory/secretory antigen, showing several bands determined through immunoblotting. RSV-Ts also had a marked reduction of T. spiralis worm burden in diaphragm. These results indicate that immune responses induced by RSV infection contribute to resistance against subsequent T. spiralis infection.

Trichinella spiralis (T.spiralis) muscle-larva (ML) excretory–secretory proteins (ESPs) contain antitumour-active substances. ESPs have been shown to inhibit tumour growth. To explore the effects of these proteins on small cell lung cancer cells and the possible mechanisms of their antineoplastic action, H446 SCLC cells were co-cultured with different concentrations of T. spiralis ML ESPs for 12, 24 and 48 h. Our results showed that T. spiralis ML ESPs significantly inhibited H446 cell proliferation, which was dose-and time-dependent. The results of flow cytometry testing indicate a clear apoptosis trend in H446 cells co-cultured with ESPs for 24 h. Reverse transcription polymerase chain reaction and Western blotting results showed increased expression of pro-apoptosis genes Bax, Cyt-C, Apaf-1, caspase-9 and caspase-3, compared with the negative control group, and decreased the expression of anti-apoptosis genes Bcl-2 and Livin. Our results suggest that T. spiralis ML ESPs can induce apoptosis in H446 cells through a mitochondrial pathway, which may be a mechanism of antineoplastic action in T. spiralis ML ESPs.

Trichinella spiralis is a parasitic helminth that can infect almost all mammals, including humans. Trichinella spiralis infection elicits a typical type 2 immune responses, while suppresses type 1 immune responses, which is in favour of their parasitism. DNA vaccines have been shown to be capable of eliciting balanced CD4+ and CD8+ T cell responses as well as humoral immune responses in small-animal models, which will be advantage to induce protective immune response against helminth infection. In this study, serine protease (Ts-NBLsp) was encoded by a cDNA fragment of new-born T. spiralis larvae, and was inserted after CMV promoter to construct a DNA vaccine [pcDNA3·1(+)-Ts-NBLsp]. Ts-NBLsp expression was demonstrated by immunofluorescence. Sera samples were obtained from vaccinated mice, and they showed strong anti-Ts-NBLsp-specific IgG response. Mice immunized with the pcDNA3·1(+)-Ts-NBLsp DNA vaccine showed a 77·93% reduction in muscle larvae (ML) following challenge with T. spiralis ML. Our results demonstrate that the vaccination with pcDNA3·1(+)-Ts-NBLsp plasmid promoted the balance of type 1 and 2 immune responses and produced a significant protection against T. spiralis infection in mice.

Trichinella spiralis is an intracellular parasitic nematode of mammalian skeletal muscle, causing a serious zoonotic disease in humans and showing a high economic impact mainly in pig breeding. Serine proteinases of T. spiralis play important roles in the host–parasite interactions mediating host invasion. In this study, we have focused on newborn larvae (NBL-1), the first identified serine proteinase from the NBL stage of T. spiralis. Five monoclonal antibodies (mAbs) directed against the C-terminal part of NBL1, were produced. These mAbs were IgG1κ isotype and specifically recognized as a common motif of 10 amino acids (PSSGSRPTYP). Selected mAbs were further characterized using antigens from various developmental stages of T. spiralis. Western blot revealed that selected mAbs reacted with the native NBL1 at Mr 50 kDa in the adult and NBL mixed antigens and NBL stage alone. Indirect immunofluorescence analysis revealed that selected mAbs intensely stained only the embryos within the gravid females and the NBL. Thus, the produced mAbs are useful tools for the characterization of NBL1 as a major antigen of Trichinella involved in the invasion of the host but also for the development of new serological tests with an early detection of T. spiralis infection.

Three expression cDNA libraries from Trichinella spiralis worms 14 h, 20 h and 48 h post-infection (p.i.) were screened with serum from pigs experimentally infected with 20 000 T. spiralis muscle larvae. Twenty-nine positive clones were isolated from the 14 h p.i. cDNA library, corresponding to 8 different genes. A putative excretory-secretory protein similar to that of T. pseudospiralis was identified. Three clones corresponded to a T. spiralis serine proteinase inhibitor known to be involved in diverse functions such as blood coagulation and modulation of inflammation. Screening of the 20 h p.i. cDNA library selected 167 positive clones representing 12 different sequences. The clone with the highest redundancy encoded a small polypeptide having no sequence identity with any known proteins from Trichinella or other organisms. Fourteen clones displayed sequence identity with the heat shock protein (HSP) 70. HSPs are produced as an adaptive response of the parasite to the hostile environment encountered in the host intestine but their mechanism of action is not yet well defined. From the 48 h p.i. T. spiralis cDNA library, 91 positive clones were identified representing 7 distinct sequences. Most of the positive clones showed high similarity with a member of a putative T. spiralis serine protease family. This result is consistent with a possible major role for serine proteases during invasive stages of Trichinella infection and host-parasite interactions.

The kinetics of the lymphoblast response in mice during the course of a primary infection with Hymenolepis nana was measured by the in vivo uptake of 125IUdR. The response was most marked in tissues local to the site of infection, involving to nodes draining the small intestine but not other areas, e.g., inguinal lymph nodes. A close correlation between these responses and the course of inflection was observed. Uptake of 125IUdR was greatest in the mesenteric lymph node (MLN) but the peak reached in this organ was later than that in Peyer's patches (PP), small intestine (SI) and spleen (S). The increase in lymphoblast activity of the MLN was similar with Trichinella spiralis; no significant blast cell response to inflection with H. diminuta was found till day 9 after injection, the results being similar to those obtained when H. nana inflections were established using cysticercoids rather than eggs. It has been shown that the increase in lymphoblast activity was closely correlated with the presence of cells which are most effective in adoptive transfer immunity. A dose-dependent effect was detected in blast cell activity of MLN in different inflection levels with T. spiralis and H. nana.

Total RNA was extracted from packed infective larvae of Trichinella spiralis by centrifugation through a 5·7 M caesium chloride cushion. Polyadenylated messenger RNA was separated from total RNA in an oligothymidylic acid-cellulose gel column. The in vitro translation of the mRNA, isolated from infective larvae of T. spiralis, was carried out using the rabbit reticulocyte cell-free translation system. Incorporation of 35S-methionine into trichloracetic acid precipitates in the lysate containing mRNA was 5 times greater than that in control. The translation products were analysed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) followed by autoradiography. Many polypeptides with molecular weights of less than 100 000 were synthesized in the lysate. A T. spiralis positive mouse serum was mixed with translation products to form antigen-antibody complexes, which were then absorbed by Staphylococcus aureus Cowan 1 strain and analysed by autoradiography of SDS-PAGE. An antigenic polypeptide with a molecular weight of 48 000 was demonstrated to react specifically with IgG antibody in T. spiralis positive mouse serum. T. spiralis larvae were cultured in methionine-free medium containing 35S-methionine, and antigenic polypeptides in somatic extracts and ES products were compared with those in translation products by autoradiography of SDS-PAGE. Several polypeptides in ES products and somatic extracts reacted specifically with IgG anitbodies in positive serum. Especially the polypeptide with a molecular weight of 48 000 in ES products strongly reacted with IgG antibody in positive serum.

Crude saline extracts of Trichinella spiralis and T. pseudospiralis infective larvae were studied by Western blot analysis using a monoclonal antibody, named ES/TA2 and produced against T. spiralis larvae. This monoclonal antibody recognized seven major antigenic components in T. spiralis larvae with apparent Mr: 45, 48, 50, 68, 70, 92 and 105 kDa and five in T. pseudospiralis larvae: 38, 50, 70, 72 and 92 kDa. SDS-PAGE of both extracts did not reveal appreciable differences in the range of molecular weights recognized by ES/TA2. These facts show the existence of immunological differences among proteins with apparently identical molecular weights.

The two-dimensional patterns (isoelectrofocusing-IEF/polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate-SDS) of S3 fractions of muscle larvae of four Trichinella isolates were compared. The comparative study concerned six groups of polypeptides. It was observed that the Garkavi isolate of Trichinella pseudospiralis was clearly different from the other isolates, and it showed the simplest IEF/SDS polypeptide pattern. The C-76 isolate of T. nelsoni had only four of the six groups, distinguishing it from the GM-1 isolate of T. spiralis and the Boev isolate of T. nativa that showed all the indicated groups.

Comparative efficacy of mebendazole and flubendazole, a p−fluor analogue of mebendazole against the encysted larvae of Trichinella spiralis (USA strain) in the diaphragm of mice and rats were studied in order to provide a better understanding of the structure-activity relationship within the benzimidazole series. Drugs given 10–100 mg/kg/day for 3 consecutive days (35–37 days post-infection) or at 300 mg/kg, 35 days post infection were significantly effective in decreasing early encysted larvae in mice. No significant differences in effectiveness against the early encysted larvae could be observed between the drugs under the present experimental conditions. Mebendazole was found to be more effective that flubendazole in decreasing old encysted larvae in mice treated 70–72 days post-infection based on a comparative study of their ED50 values. When rats were given the drugs at the dose of 10 mg/kg/day for 3 consecutive days, mebendazole was significantly effective against both early and old encysted larvae while flubendazole was not.