Trichinella Larvae Research Articles

THE EFFECT OF THE EXPERIMENTAL INVASION OF T. PSEUDOSPIRALIS ON THE MORPHOLOGY OF THE SPLEEN OF LAYING HENS (GALLUS DOMESTICUS)

Background. Еhe study of the reaction of the organs of the immune system of birds with nematodes is relevant for the development of treatment regimens. Numerous models have been developed for laboratory animals (mice and rats), carnivores (hori, etc.) and birds (quails, chickens). In the latter, a capsule-free type of trichinella parasitizes, which has a number of reproduction features. In this study, a model of experimental invasion of T. pseudospiralis was used. The role of the spleen in the formation of anti-nematodosis immunity and its reaction to the introduction of the parasite in chicken (Gallus domesticus) has been studied. The purpose of this study was to investigate morphological changes in the structure of the spleen in trichinellosis caused by T. pseudospiralis in chickens in the muscular stage of the invasive process. Materials and methods. By the method of analogues, 2 groups of 6 heads were formed. The birds of the experimental group were weighed and T. pseudospiralis larvae isolate was injected into the goiter at a dose of 2 lich. / g of body weight (3200-3600 thousand larvae per bird). T. pseudospiralis larvae used for experimental infection of poultry were previously isolated from the muscles of birds, and were maintained on laboratory animals. All chickens were kept and fed under identical conditions. In order to determine the distribution of larvae in the muscles of T. pseudospiralis poultry, 6 chickens of the experimental group were euthanized 3.5 months after experimental infection. The birds were removed from the experiment in accordance with the "Rules for carrying out work using experimental animals" and in accordance with the principles of the Declaration of Helsinki, and approved by the Institutional Review Board. The intensity of invasion (AI, lich./g) for each chicken and the average for the group and AI by the distribution of larvae in the slice were determined. Histological preparations of the spleen were prepared according to the classical method and stained with hematoxylin – eosin. Results. After digestion of muscle mass in artificial gastric juice, the number of larvae was 2570+640 l./g of muscles (average AI from muscle samples of the studied groups), no trichinella larvae were found in the control group. By CT, the largest AI was found in the muscles of the head (5.5+1.5 larvae in the section). The parenchyma of the organ of the spleen is represented by red and white pulp, in healthy birds the area of the red pulp was 10 + 5% of the area of the organ, and the white pulp 76.5 + 5% of the mass of the organ. In chickens infected with trichinella larvae, the area of the white pulp increased dramatically to 90% of the organ area and more. Conclusion. The chicken spleen is actively involved in the pathogenesis of helminthiasis of birds. The follicles of the white pulp, as in the trichinosis of white mice, grow, merging into large conglomerates. In birds, as well as in mammals, the number of large lymphocytes and plasmocytes increases, which indicates the similarity of intercellular interactions and the reaction of immunocompetent cells to the introduction of the parasite.

Outbreak of Human Trichinellosis - Arizona, Minnesota, and South Dakota, 2022.

Trichinellosis is a parasitic zoonotic disease transmitted through the consumption of meat from animals infected with Trichinella spp. nematodes. In North America, human trichinellosis is rare and is most commonly acquired through consumption of wild game meat. In July 2022, a hospitalized patient with suspected trichinellosis was reported to the Minnesota Department of Health. One week before symptom onset, the patient and eight other persons shared a meal that included bear meat that had been frozen for 45 days before being grilled and served rare with vegetables that had been cooked with the meat. Investigation identified six trichinellosis cases, including two in persons who consumed only the vegetables. Motile Trichinella larvae were found in remaining bear meat that had been frozen for >15 weeks. Molecular testing identified larvae from the bear meat as Trichinella nativa, a freeze-resistant species. Persons who consume meat from wild game animals should be aware that that adequate cooking is the only reliable way to kill Trichinella parasites and that infected meat can cross-contaminate other foods.

Outbreak of Human Trichinellosis - Arizona, Minnesota, and South Dakota, 2022.

Trichinellosis is a parasitic zoonotic disease transmitted through the consumption of meat from animals infected with Trichinella spp. nematodes. In North America, human trichinellosis is rare and is most commonly acquired through consumption of wild game meat. In July 2022, a hospitalized patient with suspected trichinellosis was reported to the Minnesota Department of Health. One week before symptom onset, the patient and eight other persons shared a meal that included bear meat that had been frozen for 45 days before being grilled and served rare with vegetables that had been cooked with the meat. Investigation identified six trichinellosis cases, including two in persons who consumed only the vegetables. Motile Trichinella larvae were found in remaining bear meat that had been frozen for >15 weeks. Molecular testing identified larvae from the bear meat as Trichinella nativa, a freeze-resistant species. Persons who consume meat from wild game animals should be aware that that adequate cooking is the only reliable way to kill Trichinella parasites and that infected meat can cross-contaminate other foods.

Morphological features of capsules of trichinella larvae in the muscle tissue of badgers of the Amur region

One of the main reservoirs of the causative agent of trichinosis in the Amur region is the badger, whose meat and fat are used for medicinal purposes or as a delicacy. Data on infection of badgers and the localization of Trichinella larvae in the muscle tissue of badgers are ambiguous. The morphological features of the development of muscle tissue in badgers are associated with lifestyle, which is likely reflected in the localization of Trichinella larvae in certain muscles. The goal is to determine the morphological parameters of capsules of Trichinella larvae in the muscle tissue of badgers in the conditions of the Amur region. The material was the muscle tissue of the skeletal muscles of the head, pectoral, pelvic limbs, muscles of the spinal column and abdominal cavity of badgers, hunted by hunters under licenses in the Amur region.Detection of Trichinella larvae was carried out by compressor trichinoscopy and digestion in individual housing, according to MUK 4.2.2747-10 “Methods of sanitary and parasitological examination of meat and meat products.” For each muscle, the intensity of invasion was determined (personal/gram). Morphological parameters of capsules of Trichinella larvae were determined using an eyepiece micrometer. The capsule shape index was calculated using the formula V=D/L.The most invaded muscles in badgers have been identified and the shape index of capsules of Trichinella larvae has been determined. Areas of natural foci of trichinosis in the Amur region have been identified. In badgers, the most infested Trichinella larvae are the head muscles (mylohyoid muscle, tongue muscle tissue and masticatory muscle), which are preferable to take for diagnosing trichinosis in this animal species.The rounded shape of the capsules of Trichinella larvae (shape index 0.72), characteristic of badgers of the weasel family, was established. The areas of natural foci of trichinosis have been identified - Mikhailovsky, Seryshevsky, Blagoveshchensky, Tambov and Ivanovo administrative districts of the Amur Region. Of particular concern is infection in the southern, most populated areas, where there is a high probability of the transition of trichinosis from natural foci to anthropurgic and synanthropic ones.

Inactivation of Trichinella spp. in naturally infected boar meat after Pulsed Electric Field (PEF) treatments

Larvae of the nematode Trichinella are capable of causing parasitic infections in humans after the consumption of uncooked meat or meat products, leading to severe symptoms and even death. Meat inspection is costly and tends to progressively be derogated in holdings applying controlled housing conditions in certain regions. Our study focuses on the evaluation of the efficacy of Pulsed Electric Fields (PEF) in the inactivation of Trichinella spp., including excysted larvae isolated by artificial digestion and encapsulated larvae found in meat from naturally infected wild boars. Microscopic examination of unstained and propidium-iodide-stained larvae suspensions showed that most of the excysted larvae were inactivated 10 min after an intermediate PEF treatment (1 kV/cm, 0.41 kJ/kg). Treating excysted larvae with the mildest PEF treatment (0.5 kV/cm, 0.05 kJ/kg) combined with a 3% NaCl incubation resulted in synergistic inactivation. The application of 3 kV/cm (20 kJ/kg) to wild boar meat resulted in the inactivation of over 90% of encapsulated Trichinella larvae. The viability of Trichinella in meat was inversely correlated to the field strength applied (1–6 kV/cm) for equal energy input (20 kJ/kg). These findings demonstrate that PEF technology can potentially serve as a novel strategy for the inactivation of Trichinella larvae in meat.

Identification of Sarcocystis and Trichinella Species in Muscles of Gray Wolf (Canis lupus) from Lithuania.

Apicomplexan Sarcocystis and Trichinella nematodes are food-borne parasites whose life cycle is carried-out in various wildlife and domestic animals. The gray wolf (Canis lupus) is an apex predator acting as an ecosystem engineer. This study aimed to identify the species of Sarcocystis and Trichinella found in the muscles of gray wolves in Lithuania. During the 2017-2022 period, diaphragm, heart, and hind leg samples of 15 animals were examined. Microscopical analysis showed the presence of two types of Sarcocystis parasites in 26.7% of the analyzed muscle samples. Based on the sequencing of five loci, nuclear 18S rDNA, 28S rDNA, ITS1, mitochondrial cox1, and apicoplast rpoB, S. arctica, and S. svanai were identified. The current work presents the first report of S. svanai in gray wolf. Phylogenetically, S. svanai clustered together with S. lutrae, infecting various carnivorans, and S. arctica was most closely related to S. felis from domestic cats. Trichinella spp. were found in 12 gray wolves (80%). For the first time, Trichinella species were molecularly identified in gray wolves from Lithuania. Trichinella britovi was confirmed in all of the isolated Trichinella larvae using a multiplex PCR. Gray wolves in Lithuania may serve as a major source of zoonotic pathogens due to the presence of these parasites.

Trichinella spp. in Slaughtered Pigs of India: From Neglected Disease to an Emerging Food Safety Threat for Public Health

Background. In India, Trichinella nematode worm remains highly neglected due to the paucity of research. Recent trichinellosis outbreaks in humans associated with pork meal in north India have highlighted an emerging food safety concern due to this neglected parasite. Aim. This study aimed to ascertain the existence of Trichinella species and to identify them in slaughtered pigs intended for human consumption in the Punjab and Uttaranchal regions of North India. Materials and Methods. A total of 1,194 slaughter pig tongue samples were screened in 239 pools using the double separatory funnel method for recovery of Trichinella larvae. The species of recovered larvae were confirmed by multiplex PCR assay and sequencing. A phylogenetic tree was constructed to ascertain the closest lineage. Results. This study reported 3.77% and 1.26% Trichinella positivity in pooled and individual pig samples, respectively. Pigs slaughtered in Punjab reported higher positivity (1.73%) than pigs in Uttaranchal (0.81%). Among all places, Jalandhar recorded highest positivity of 5.66%, followed by 2.22% in Nainital and 0.8% in Patiala, whereas none of the pig samples from Chandigarh, Ludhiana, Bathinda, Tehri Garhwal, Pauri Garhwal, Kashipur, Haridwar was positive. Molecular confirmation by PCR and sequencing confirmed the recovered Trichinella larvae as T. britovi and T. nelsoni. Conclusion. Trichinella parasite remained highly neglected in India; however, the detection of sylvatic Trichinella species in pigs intended for human consumption indicated the emergence of zoonotic foodborne risk at wild animal-domestic pig and human interfaces. To the best of our knowledge, this is the first study reporting T. britovi and T. nelsoni in pigs of North India. Trichinella positivity in slaughtered pigs is an early alarm for the emergence of foodborne risk from this neglected parasitic worm. Considering the importance of pigs as a source of meat and their role as a reservoir for Trichinella raised the food safety concern that warrants strict meat inspection and extensive studies on neglected parasites in India.

Trichinellosis dissemination among wild carnivores in the Republic of Kazakhstan: A 10-year study.

Trichinellosis is caused by a species of roundworm called Trichinella and is an invasive disease causing severe medical, veterinary, and socioeconomic problems worldwide. More than 100 mammalian species are Trichinella hosts. Among domestic animals, pigs and dogs are prone to trichinellosis. An essential aspect of controlling the spread of infection is to identify the number and level of infections in wild carnivores in the country. However, the number, habitats, and movements of wild animal Trichinella hosts in Kazakhstan have not been reported yet. This study aimed to monitor the wild animal habitat nearby the settlements for tracking the trichinellosis speading among carnivores. Wild carnivorous animals were captured in seven regions of the Republic of Kazakhstan. The carcasses of corsacs, wolves, foxes, wild boars, and badgers were studied. Muscle tissue samples from spontaneously infected wild animals were collected. The digestion method in "GASTROS-2M" was used to isolate Trichinella spp. from animal muscles. The species of the parasite was determined by a polymerase chain reaction for 5S spacer of Trichinella ribosomal DNA with subsequent sequencing by Senger. Statistical analysis methods were performed for average value in Microsoft Excel 2010. The results of the research showed that among 155 animals wolves (20.4%) and foxes (26.7%) were the most infected with invasive Trichinella larvae. The invasion intensity was 503.6% in foxes and 289.7% in wolves. However, badgers (164%), wild boars (0%), and corsacs (0%) presented lower invasion levels. Using specific primers, larvae samples were identified as Trichinella nativa. The results of monitoring revealed the spread of trichinosis among wild animals: wolves, foxes, badgers. The Karaganda, Kostanay, Western Kazakhstan, and Akmola regions had the largest distribution of wild animals infected with trichinellosis. In total, 20% of the 155 studied animals were infected. The greatest invasion intensity was typical for wolves, foxes and badgers. It is necessary to monitor the spread of trichinellosis among wild carnivores to control the epidemiological situation and reduce the level of spontaneous infection among animals. Regular monitoring of habitats and carnivores must be conducted within the country and in the border areas.

ON THE ISSUE OF CHANGING THE MORPHOLOGY OF THE SPLEEN IN NEMATODOSES IN MICE DURING IMMUNOSTIMULATION

Background. The study of the reaction of the immune system organs to the introduction of immunomodulators in nematodes is relevant for the development of treatment regimens. The purpose of the study was to examine the spleen (the organ of immunogenesis that plays an important role in the formation of immunity). In addition, the aim of the study was also to find the morphological changes of nematodes (capsules of trichinella larvae) and the features of siphatiа.
 Materials and methods. In the experiment, 35 white mice were used, which were divided into 5 groups of 7 animals in each group. The first and second groups were injected with 0.004 mg saline solution subcutaneously, the 3rd and 4th groups were injected with polyoxidonium at a dose of 0.004 mg/mouse, the 1st and 3rd groups were infected with trichinella larvae, the 2nd and 4th were spontaneously affected by syphilis, the 5th group served as control. Evaluation of the protective properties of polyoxidonium in laboratory models with trichinosis was carried out by determining the intensity of invasion during postmortem studies of all muscle groups of the animal and siphations by the number of eggs in perianal scrapings.
 Results. The study showed protective efficacy with the introduction of polyoxidonium was 99.43%, 57 ± 20 trichinella larvae / per animal were detected in the entire muscle mass, while only 72% with syphaciosis. The parenchyma of the organ of the spleen is a red-white pulp, in healthy animals the area of the red pulp was 70+5% of the area of the organ, and the white pulp was 26.5+ 5% of the mass of the organ. In animals infected with nematodes, the area of the white pulp increased dramatically to 50% of the organ area or more.
 Conclusion. Significant protective activity of polyoxidonium (99.43%) was established in parasitological studies, which was accompanied by an increase in the area of lymphoid tissue associated with the intestine. When studying histological preparations of the spleen, it was noted that the restructuring of the structure under the action of trichinella and siphacia antigens is of the same type: the ratio of red and white pulp, their cellular composition changes. It was found that in all infected animals, the area of the white pulp increased dramatically by more than 60% with trichinosis and up to 50% with syphacosis of the organ area or more. The final result of this thesis was using polyoxidonium, there was also a decrease in the number of eggs in the control group and changes in the number and actual distribution of trichinella larvae in various muscle groups.

Morphological features of capsules of trichinella larvae in wild animals of the amur region

The problem of trichinosis on the territory of the Far East has a pronounced natural focal character with the predominant circulation of the causative agent of trichinosis in wild animals. The main species circulating in the Amur Region is the capsule- forming species T. spiralis. The ability to form capsules is one of the biological features of Trichinella larvae and a necessary component of the process of their survival. The thickness of the walls of the capsule gradually increases while the larva and intracapsular muscle sarcoplasm with nuclei remain alive. At the same time, the morphological variability of Trichinella capsules under the influence of many ecological and biological factors was noted.The goal is to determine the morphological features of the capsules of Trichinella larvae in wild animals in the Amur region.We conducted studies of the muscle tissues of wild animals by the method of compressor trichinelloscopy and the method of digestion in artificial gastric juice, according to MUK 4.2.2747-10 "Methods of sanitary and parasitological examination of meat and meat products" to determine the presence of Trichinella larvae. To establish the morphological features, the length and width of the capsules, the thickness of the capsule wall from the sides and at the poles, and the thickness of the larva itself were determined using an eyepiece micrometer. The capsule shape index (V) was calculated as the ratio of the diameter to its length (V=D/L). The shape of capsules of Trichinella larvae in different species of wild animals was determined. The relationship between the morphological parameters of the capsule of the larvae of Trichinella has been established. Indicators of the thickness of the wall of the capsule from the sides and the thickness of the wall of the capsule at the poles can be used to determine the age of Trichinella larvae.

Scheme of Effective Epidemiological Investigations in Trichinella Outbreaks on Pig Farms

Trichinellosis is a parasitic, zoonotic disease caused by larvae of the genus Trichinella. Infection occurs via the consumption of raw or undercooked meat containing this parasite. Symptoms of the disease manifest as intestinal disorders, followed by facial swelling, fever, muscle pain and other symptoms, eventually leading to neurological and cardiac complications and even death. In Europe, trichinellosis is most often associated with the consumption of meat from wild boars, pigs and horses. In recent years, wild boars that are hunted illegally and not tested for Trichinella spp. have been the most common cause of trichinellosis in humans; however, there have also been cases where infected pigs have been the source of infection. When trichinellosis is suspected in humans, epidemiological measures are taken to identify the source. Similarly, an epidemiological investigation should be initiated whenever Trichinella spp. has been detected in pigs. However, commonly used actions do not provide sufficient data to determine the source of infection for pigs and to prevent further transmission. Therefore, in this article, we propose a scheme for effective epidemiological investigations into Trichinella outbreaks on pig farms that can help trace the transmission mechanisms of the parasite and that takes into account currently available testing tools. The proposed pathway can be easily adopted for epidemiological investigations in routine veterinary inspection work.

Parasites of five vagrant Polar bears (Ursus maritimus) swimming to Iceland during 2008 to 2016

During 2008 to 2016, five polar bears (Ursus maritimus) swam from the East Greenland population to Iceland and were shot soon after walking ashore. Each bear was dissected. Ectoparasites were searched for in their ears and fur, helminths in the gastrointestinal tract and Trichinella larvae in muscles. Protozoan cysts, oocysts and helminth eggs were also searched for in faecal samples. No ectoparasites were detected. Two bears (40%) hosted fourth stage larvae of the nematode Contracaecum osculatum (strain B) in the stomach. Characteristic scars, noted as craters in the rectum wall, indicated previous acanthocephalan infection in one bear. Three polar bears were infected by the nematode Trichinella nativa. No protozoan parasites were detected in faecal samples, but cysts of the heterokontophyte Blastocystis sp. were found in faeces of two bears (40%). This is the first report of C. osculatum, Blastocystis sp. and an acanthocephalan infection in free-living polar bears. Keywords: Iceland, parasites, Ursus maritimus, polar bear, vagrant, new host records

Establishment of a method for detecting Trichinella spiralis in ovine muscle tissues using real-time fluorescence quantitative PCR

Trichinellosis is caused by Trichinella spiralis, a meat-borne zoonotic disease transmitted to humans through the consumption of infected undercooked or raw meat. Surveillance using safe and precise diagnostic tools to diagnose T. spiralis in sheep is needed to assess the incidence and probability of transmission from sheep to humans. In this study, we developed a real-time PCR assay to detect T. spiralis DNA in ovine muscle samples that can be used as an alternative surveillance tool to ensure food safety using newly designed primers. The assay is specific for the Scfld4 gene of Trichinella (T1) and enables the detection of larvae in ovine muscle tissue samples with high sensitivity and specificity. Trichuris ovis, Oesophagostomum dentatum, Haemonchus contortus, and Bunostomum trigonocephalum showed no nonspecific amplification. The assay could detect Trichinella DNA concentrations as low as 0.0026 ng/μL, equivalent to 0.0064 larvae, indicating a high sensitivity for T. spiralis detection. We used this real-time PCR to detect 73 ovine muscle samples from an ovine abattoir, and five samples tested positive via real-time PCR but negative via microscopy. This assay may provide a more specific and sensitive method for rapidly detecting Trichinella larvae in ovine muscle tissues.

Trichinosis of Marine Mammals in the Territory of Chukotka

Chukotka is the only region of the Russian Federation where traditional fishing of marine mammals, including the gray whale Eschrichtius gibbosus, is conducted. More than 70% of the indigenous population of the coastal settlements of the Chukchi Peninsula eat the meat of marine mammals. Due to the huge distances between communities, lack of infrastructure, limited access to medical and veterinary care, isolated studies of marine mammal infestation with trichinella larvae are being conducted.For the first time, trichinella in the Pacific walrus Odobenus rosmarus divergens in Chukotka were recorded in the coastal zone of the Bering and Chukchi Seas in the 1970s. In the future, trichinosis has not been studied in this region, which confirms the relevance of our work. Infection of marine mammals was studied by trichinelloscopy (compressor and biochemical). Bioassays were collected during fishing by sea St. John's wort in the village of Lorino. Infection rates were determined. Studies conducted on the Chukchi Peninsula confirmed the infection with trichinosis of the Pacific walrus and revealed the larvae of trichinella in lakhtak Erignathus b.nauticus and ringed seal Phoca hispida, and later in larga Phoca largha. The extent of invasion varied from 0.9% in larga to 4.3% in lakhtak. The gray whale is the most popular food item in the diet of the indigenous inhabitants of Chukotka. According to the results of the research, out of 119 individuals of gray whales, trichinella were not found. Given the trophic‐chorological connections of marine mammals, it is difficult to imagine a way of transmission of trichinella in marine ecosystems. However, previously obtained research results allow us to do this. On the Arctic coasts, especially near settlements, there are a large number of corpses of dogs, cats, rats, voles, carcasses of small seals that fall into marine ecosystems. Invertebrates, their adult and larval forms, as well as vertebrates ‐ fish and birds ‐ occupy an important place in the process of disposal of corpses. Studies have shown that various types of invertebrates from 1 to 59 hours, and vertebrates from 28 to 95 hours can be direct or indirect sources of the pathogen of invasion and contribute to their mechanical transfer. Thus, in the conditions of coastal Arctic marine ecosystems, successful circulation of trichinella is carried out, thanks to human economic activity and the specifics of the trophic‐horological relationships of obligate and potential host species. Therefore, monitoring of trichinella invasion in these regions is vital.

FEATURES OF THE DISTRIBUTION OF TRICHINELLA LARVAE IN THE MUSCLES OF SPONTANEOUSLY INFECTED RED FOXES (VULPES VULPES)

The issues related to the distribution of trichinella larvae in various groups of skeletal muscles of animals are quite relevant, as they are of great importance for the diagnosis of trichinosis. There is a lot of contradictory information in scientific papers about the distribution of trichinella larvae in the muscles of spontaneously infected predatory mammals. The purpose of our research was to study the distribution of trichinella larvae in various skeletal muscle groups in spontaneously infected red foxes (Vulpes vulpes). Detection of trichinella larvae was carried out by compressor trichinelloscopy and by the method of digesting muscle tissue in artificial gastric juice. Capsule-forming trichinella (Trichinella spp.) were found in animal muscles. The most intensively affected were the large masticatory muscle (68.1±30.7 larvae in 1 g of muscle tissue), diaphragm (65.3±25.6), intercostal muscles (63.7±23.1) and tongue root muscles (58.9±25.2). A lower intensity of invasion was noted in the splenius (36.6±14.4). In the triceps muscle of the shoulder (2.1±2.2) and the calf muscle (2.9±2.5), a very low intensity of invasion was recorded. Trichinella larvae were not found in the latissimus dorsi muscle, trapezius muscle, biceps femoris muscle, superficial gluteus muscle and middle gluteal muscle. Thus, in the spontaneously infected red foxes studied by us, the highest invasion intensity was noted in the muscles of the trunk and head.

Bevacizumab: A new take on therapy of muscle phase of Trichinella spiralis infection

Trichinellosis is a zoonosis that causes health and economic problems worldwide. The available therapy is far from perfect as the conventional drugs used against Trichinella spiralis (T. spiralis) are active against the intestinal adult parasites but much less active against encapsulated larvae in muscles. Therefore, this work aimed to evaluate the effect of the anti-angiogenic agent, bevacizumab, on the muscle larvae of T. spiralis. For this aim, T. spiralis-infected mice were treated by two different doses of bevacizumab, thereafter larval counts as well as biochemical and pathological changes were evaluated in the muscles. The larval burden was reduced in the muscles of treated mice, denoting a detrimental effect of bevacizumab against encapsulated Trichinella larvae. Moreover, there was marked improvement of muscle inflammation with the treatment, evidenced by reduction of the proinflammatory cytokines (IL-6 and TNF-α) and regression of the inflammatory infiltrates in histological sections. Amelioration of oxidative stress in the muscle was also observed in treated animals with reduction of malondialdehyde and carbonic anhydrase III and increase in superoxide dismutase levels. Finally, the treatment induced downregulation of the expression of VEGF and CD31, denoting suppressed angiogenesis. All these beneficial effects were found to be dose dependent. In conclusion, bevacizumab exhibited anthelmintic, anti-inflammatory, antioxidant, and anti-angiogenic activities against Trichinella during the muscular phase of infection. Therefore, bevacizumab could be considered as a useful adjuvant treatment in the late stages of trichinellosis.

Validation of the Magnetic Stirrer Method for the Detection of Trichinella Larvae in Muscle Samples Based on Proficiency Tests Results.

Trichinellosis is a zoonotic disease caused by the nematodes of the genus Trichinella. Infection takes place through the consumption of infected meat containing live larvae. The only way to prevent the disease is to break its epizootic chain. To ensure effective control of Trichinella spp., a range of preventive and control measures have been undertaken. These efforts have been focused on controlling Trichinella in domestic pigs, the main source of the disease. Artificial digestion is also the reference point for other methods for Trichinella risk control. Descriptive data validation of the digestion assay was presented in 1998 based on results published by scientific laboratories. Herein, we supplement those data by characterizing the method’s performance in inter-laboratory comparisons. The source of data was the results of Proficiency Testing conducted in 2015–2019. Samples were contaminated by 0, 1, 3, and 5 larvae. In total, 7580 samples were examined by the laboratories. Based on Proficiency Testing results, the main parameters characterizing the method performance in field conditions were established as follows: specificity, 97.3%; sensitivity, 86.5%; accuracy, 89.2%; uncertainty, 0.3; limit of detection (LOD), 1 larva; and limit of quantification (LOQ), 3 larvae.

Trichinosis in the Rostov oblast

In the Russian Federation, cases of infection with trichinosis in a population of people or animals are annually recorded. Trichinosis is intestinal and tissue helminthiasis of humans and a number of mammals, caused all over the world by nematodes. A person becomes infected with the parasite by eating meat containing live encapsulated Trichinella larvae. Mating takes place in the gastrointestinal tract, fertilized females are introduced into the intestinal mucosa with their anterior thinned ends. The clinical picture of trichinosis is accompanied by the development of myositis, degeneration of muscle fibers, and multiple edema. Deaths are not uncommon due to necrotic ulcerative lesions of the intestine and internal bleeding.

Results of Proficiency Testing for Trichinella in Poland, 2015-2019.

Trichinellosis is a zoonotic meat-borne disease caused by the nematodes of the genus Trichinella. Meat containing live Trichinella larvae is a source of infection. The examination of meat for Trichinella was introduced in 1869, but the digestion method for this did not appear in Poland until the late 1970s. Nowadays, the meat of all food animals susceptible to Trichinella spp. is examined in the frame of official post mortem control with the digestion method. The majority of laboratories in Poland meet the requirements of the ISO/IEC 17025 Standard (352 field laboratories). Laboratory personnel participate in quality control programs. This paper presents the results of proficiency tests (PTs) organized within 2015–2019 in Poland. Over this period, the laboratories examined 7580 samples (contamination levels: zero, one, three, and five larvae). Each laboratory was provided with a set of samples (one negative and three positive). Over 95% of the samples were considered correct in qualitative assessments, though the results of the quantitative evaluations were slightly lower, with 89% of samples being considered correct. Based on a sample evaluation, 88% of laboratories passed the PT comparison. A slight decrease was observed in the examination of samples spiked with five larvae, and great progress was achieved in samples containing three larvae. Low levels of sample contamination are sought after in laboratories but may make evaluations difficult. For this reason, we must consider increasing the number of larvae added to the samples in the next PTs.

Reprint of: The retention and concentration of glycogen in Trichinella nativа in the winter-spring period

The metabolism of Trichinella spp. is primarily anoxybiotic in nature. Their main energy source is glycogen, which is stored in the stichocites at the muscular stage of the larval development. When subject to tow temperatures the Trichinella larvae consume glycogen and neutral fats to provide for basal metabolism until the energy supplies reach the critical level. The present study establishes the glycogen concentration as well the invasive activity of T. nativа when affected by low temperatures in natural conditions. The carcasses of infected laboratory rats were placed in containers beneath the snow cover, in the natural conditions of a game husbandry in Central Russia. The viability, invasive capacity and the glycogen level were monitored in the Trichinella larvae monthly. The invasive capacity of Trichinella larvae was established based on the presence of the larvae in the muscular tissue of laboratory mice after the peroral administration of the helminth larvae. On the 45 day of the experiment, the mice were euthanized by cervical dislocation, and if the Trichinella larvae could be discovered in the muscular tissue with the help of the trichinelloscopic compression method, the invasive capacity of the Trichinella larvae was viewed as positive. To establish the quantitative value of glycogen content in Trichinella larvae a modified method was used. In order to measure the glycogen level in the T. nativa larvae isolated by fermentation larvae were counted in one drop of the suspended sedimentation in the Migacheva-Kotelnikov chamber. To establish the quantitative value of glycogen content in Trichinella larvae a method based on the treatment of glycogen with iodine, optical density measurement with a refractometer MКMФ-02 was used. For the purpose of measuring the concentration of glycogen in Trichinella larvae in the suspended sedimentation a calibration curve was used. The studies showed that the viability indicator of the Trichinella larvae which had been preserved in natural conditions in the four months of the winter-spring period, in the muscular tissue of laboratory rats remained high (over 90 %). The glycogen concentration in one helminth larva was 0.041 μg in January, 0.033 μg in February, 0.015 μg in April. The invasive capability of the preserved Trichinella larvae was considerably reduced to 33.3 %. In the winter period, under temperatures below 0 °C, a decrease in the glycogen concentration in the Trichinella larvae was observed.