In the present report we study the proteolytic activity of the excretion-secretion and crude extracts of different stages of Trichinella spiralis (Owen, 1835) Railliet, 1895, (muscle-stage larvae, adult worms before and after mating, and newborn larvae) using natural substrates (structural and hematic mammalian proteins). The analysis of the results allow us to set up a certain stage-specificity, as well as an important relationship between the protease patterns throughout the parasite life cycle and how the parasite may overcome both mechanical and humoral barriers within the host. Muscle-stage larvae present a great activity against structural proteins (collagen), while newborn larvae and adult worms degrade principally hematic proteins (hemoglobin, fibrinogen and immunoglobulin G).
The potential role of intestinal intraepithelial lymphocytes (i-IELs) in the generation of host protective immunity after helminth infection was investigated using the Trichinella spiralis (Owen, 1835)/mouse model. In this study we found a significant rise of TCRyô i-IELs (P < 0.001) concurrent with the jejunal goblet cells (GC) hyperplasia in T. spiralis-infected C57BL mice on day 4 p.i. However, no direct relationship between the kinetics of the increase in TCRy5+ i-IELs and T, spiralis expulsion was observed in infected mice. Taken together, these results implicate that γδ i-IELs probably perform a unique functions related to the regulation of the CiC proliferation accompanying T. spiralis gut infection. As is known, these TCRyS* i-IELs may release mediators or growth factors that in turn influence GC differentiation. With the use of dexamethason (DEX), a potent anti-inflammatory agent which also induces apoplotic ceil death in i-IELs, wc have confirmed that the expulsion of T. spiralis from the mouse gut is accompanied by an inflammatory response. Indeed, the GC are clearly involved in these phenomena, apparently under the regulation by TCRy8+ i-lEL-mediated responses, since DEX abrogated GC proliferation in T. spiralis-infected C57BL mice and subsequently augmented adult worm burden. Our data also show that the rejection of adult worms starts concurrently with a significant increase in TCRaß* and CDS* i-IELs (P < 0.05 and P < 0.01, respectively), namely by day 7 p.i. At the same time, CD4* cells significantly decreased (P < 0.05) in the intestinal epithelium of T. spira/ir-infected, ví uninfected mice. These results may indicate that the TCRaß4 and CDS* i-IELs act as effectors of anti-7’, spiralis defence reactions. The implications of these findings for the potential role of intestinal intraepithélial CD8 and TCRaß' cells in the pathogenesis of the intestinal lesions during T. spiralis gut infection are discussed.
Excretory/secretory products (ES), collected from in vitro cultures of muscle larvae (l-l) of Trichinella spiralis (Owen, 1835) were examined for the presence of proteolytic enzymes. Several discrete proteinases in the size range of 25-55 kDa were identified by substrate gel electrophoresis and were characterised according to pH optima, substrate specificity and inhibitor sensitivity using azocasein assay. Serine, cystcinc and metalloproleinases active at pi I 5-7 were identified. The serine proteinases were found to predominate and some of them were found to be specific for the larval stage of the parasite. The results from the substrate analysis indicated the presence of collagenolytic and elastolytic activities. The proteinase activity was inhibited by IgG isolated from T. s/nrato-infcctcd mice, an observation of relevance to understanding host/parasite interactions and, ultimately, the development of anti-Trichinella vaccine.
An outbreak of trichinellosis occurred in Stari Banovci, a settlement in the municipality of Stara Pazova, Srem, Republic of Serbia, in March-April 2019. A total of 28 persons were exposed and trichinellosis was confirmed in 24 of them. This outbreak involved members of eight families, their relatives and friends. The infection, due to Trichinella spiralis (Owen, 1835), was associated with consumption of pork sausages procured in a local butcher's shop. The trace-back study revealed that the meat originated from swine that was raised on a small farm belonging to the owner of the shop, who did not have permission from the Veterinary Directorate for slaughtering animals and who put on the market sausages prepared from uninspected meat. Trichinellosis was accompanied by typical clinical symptoms. However, the unusual occurrence of high percentage of pulmonary complications was noticed. The description of this outbreak indicates that medical practitioners should initiate treatment immediately in cases of high suspicion of trichinellosis, even if the serology is negative, to prevent the complications of the disease. In spite of significant achievements in the control of Trichinella infection among domestic pigs and humans in the last 10 years, it is obvious that such cases of breeding animals under inappropriate conditions, slaughtering them without approval and placing uninspected pork on the market represent a source of sporadic outbreaks in Serbia.