Trichinella spiralis infection and transplacental passage in human pregnancy.

Infection by Trichinella spp. during pregnancy still arises many questions. Worldwide an important number of trichinellosis outbreaks have occurred over time where pregnant women were or might have been involved. Parasitological and immunoserological parameters, clinical background and transplacental passage of Trichinella spiralis of six pregnant women, from different outbreaks, were studied. Serum samples were collected from patients and their children: at pregnancy, at delivery, newborn and/or infant (≥1 year-old). Total immunoglobulins (Igs) and isotypes against excretion-secretion products from muscle larvae (ESP-ML) and newborn larvae (NBL) of T. spiralis were detected by immunoserological techniques. Sera helminthocytotoxic activity against NBL was evaluated by antibodies dependent cell cytotoxicity assay. Patients presented similar clinical symptoms. Mother's sera showed differences in the presence and titres of Igs, IgE, IgG1 and IgG4 against NBL surface. All of them showed helminthocytotoxic activity against NBL, four in progesterone dependent manner and the other two by antibodies. Igs anti ESP-ML were present in mother's sera, with differences in the isotypes detected. Anti-ESP-ML IgE, IgA and/or IgM in newborn sera were observed. Three out of four infants showed specific Igs; one even at 8 years-old. The distinct immune response between mothers at pregnancy evidenced by sera helminthocytotoxic activity and immunoserological parameters may be associated with a different parasite burden exposition. Specific Igs observed in newborns would be a suggestion of transplacental passage of this Igs and/or their production by the fetus. Specific Igs found in infants sera suggests that newborn larvae transplacental passage is possible.

Regulatory parameters of the lung immune response during the early phase of experimental trichinellosis.

Parasitic infection caused by Trichinella spiralis provokes an early stimulation of the mucosal immune system which causes an allergic inflammatory response in the lungs. The present work was intended to characterize the kinetics of emergence of regulatory parameters in Wistar rat lungs during this early inflammatory response, between days 0 and 13p.i. The presence of regulatory cells such as regulatory T cells (Tregs) and alternatively activated macrophages (AAM) was analyzed in lung cell suspensions. Moreover, a regulatory cytokine (TGF-ß) was studied in lung tissue extracts. Considering that newborn larvae (NBL) travel along the pulmonary microvasculature, the ability of this parasite stage to modulate the activation of lung macrophages was evaluated. For this purpose, lung macrophages from non-infected or infected rats (day 6p.i.) were cultured with live or dead NBL. Arginase activity (characteristic of AAM) and nitric oxide (NO produced by iNOS, characteristic of classical activated macrophages) were measured after 48h. Our results revealed a significant increase in the percentage of Tregs on days 6 and 13p.i., arginase activity on day 13p.i. and TGF-ß levels on days 6 and 13p.i. Lung macrophages from non-infected rats cultured with live NBL showed a significant increase in arginase activity and NO levels. Live and dead NBL induced a significant increase in arginase activity in lung macrophages from infected rats. Only live NBL significantly increased NO levels in these macrophages. The present work demonstrates for the first time, the emergence of regulatory parameters in the early lung immune response during T. spiralis infection. The immumodulatory properties exerted by NBL during its passage through this organ could be the cause of such regulation. Moreover, we have shown the ability of NBL to activate macrophages from the lung parenchyma by the classical and alternative pathways.

Description of an outbreak of human trichinellosis in an area of Argentina historically regarded as Trichinella-free: the importance of surveillance studies.

Trichinellosis is an important food-borne zoonosis which is not treated as a major public health concern in Argentina. After more than 20 years without reports of infection in an area regarded as Trichinella-free, research studies reported that infection occurred in humans, pigs and game animals, including the recent outbreak of human trichinellosis revealed here. The outbreak, affecting 64 individuals, occurred in July 2010 in the province of Entre Ríos. Epidemiological studies, clinical observations, laboratory analyses and immunoserological specific assays (indirect immunofluorescence, IIF, and ELISA) were performed. Food samples were analyzed by artificial digestion, and Trichinella larvae isolates were identified to the species level by multiplex PCR. The main source of infection, commercially available food, had a parasite load of 1.1 muscle larvae per gram. Larvae were identified as Trichinella spiralis. Patients presented predominantly with oedema, fever and myalgia; and laboratory findings and/or immunoserological tests were positive for trichinellosis. Individuals received outpatient treatment. No deaths or secondary sequelae were recorded. Results suggest that the presence of T. spiralis infection should be suspected in all endemic areas, especially where animal husbandry and official food safety controls are not properly conducted. The lack of the cases reported ought not to be taken as a proof of parasite absence. We highlight the importance of the urgent need to implement interdisciplinary and inter-institutional programs aimed to control infection transmission, to guarantee food safety and to conduct epidemiological surveillance studies.

Experimental infection with Trichinella T12 in domestic cats.

Trichinella spiralis has been documented in wild animals in Argentina, including puma, armadillos, rats and wild boars. In 2008, molecular analysis identified Trichinella T12 from a naturally infected puma (Puma concolor) from Patagonia. The aim of the present work was to study the relationship between the infectivity and pathology of Trichinella T12 in the puma and in domestic cats, and the possible risks that may be present for transmission among these animals. Two cats (A and B) were orally-infected with 3300 and 1850 Trichinella T12 muscle larvae, respectively; one additional cat was used as a control. During the 54 days post-infection, a daily examination was performed which included monitoring body temperature, and cardiac and respiration rates; the animals were then euthanized. Hematological studies included hematocrit (%), hemoglobin (g/dl), and white cell, neutrophil, lymphocyte and eosinophil counts. Blood biochemistry included urea, creatinine, AST, ALT, CK, LDH and ALP. An ELISA assay was also performed. At necropsy, organs (liver, spleen, brain, cerebellum and kidney), nails and muscle samples were obtained for histopathology studies and artificial digestion. The muscles that were studied included the diaphragm, massetter, cutaneous, temporal, intercostals, lumbar, tongue, limbs, neck and tail. Clinical signs, such as anorexia, diarrhea, vomiting, shaggy hair, decay and muscle pain, were observed in both cats. The eosinophil counts were elevated in both cats A and B. Trichinella larvae were recovered from all of the muscles analyzed where the histopathology showed larvae in several muscles without degenerative reaction. Neither larvae nor lesions were observed in non-muscular organs. Cat A had a maximum of 246 larvae per gram (lpg) in the temporal muscle and a minimum of 80 lpg in the tongue, while cat B had a maximum of 65 lpg in muscles of the leg and a minimum of 10 lpg in tail muscles. This study represents the first record of experimental infection of cats with Trichinella T12.

Trichinella spiralis infection rapidly induces lung inflammatory response: the lung as the site of helminthocytotoxic activity.

In the present work, we studied the kinetics of the appearance of different immunological parameters in the lungs during the intestinal phase of infection with Trichinella spiralis. We also evaluated the lung's role in the retention and death of this helminth in its migratory stage. To study these parameters, we used lung extracts, lung cell suspensions and rat lung tissue sections. During the intestinal phase of infection (days 0-13 post-infection, p.i.), an inflammatory response is elicited in the lungs, which reflects humoral, cellular and functional changes. These changes included an increased number of mast cells and eosinophils and the local production of IL-4, IL-5, IL-10, TNFα, IFNγ, IL-13, CCL11 and CCL28. We found hyperplasia of the bronchus-associated lymphoid tissue (BALT). Total and specific IgA, IgE, IgG1 and IgG2a were detected locally. The retention of the migratory larvae in the lung, together with the ex vivo cytotoxic capacity of the lung cells and antibodies present in the lung extracts, suggested that the lung was one of the immune defense organs against the pathogen's migration stage.

Clinical, haematological, biochemical and economic impacts of Trichinella spiralis infection in pigs.

The purpose of this work was to assess the clinical, haematological and biochemical responses of pigs experimentally inoculated with Trichinella spiralis. Groups of three pigs were inoculated per os with 100, 500 and 5000 T. spiralis muscle larvae, two pigs were used as control. Clinical evaluation of disease in pigs included daily examination, rectal temperature measurements and cardiac and respiration rates. Haematological studies included: hematocrit (%), hemoglobin (g/dl), and white cell, neutrophil, lymphocyte and eosinophil counts. Blood biochemistry included: bun (mg/dl), creatinine (mg/dl), AST (UI/l), ALT (UI/l), CPK (UI/l) and ALP (UI/l). No significant differences were observed in rectal temperature and in cardiac and respiration rates between inoculated animals and the control group (p> or =0.05). Significant differences were detected (p< or =0.05) in the values of % hemoglobin, and eosinophils, as well as in the values of CK, ALP, AST and ALT. The variations observed in some cases were related to the number of T. spiralis larvae inoculated and varied with the number of days post-infection. Inoculated pigs showed significant differences (p< or =0.05) in weight gain when compared with uninoculated controls. This study has clinical, haematological, and enzyme alterations in Trichinella infected pigs provides a better understanding of acute and chronic trichinellosis in pigs.

Trichinosis.

Trichinosis is a worldwide zoonotic disease closely related to cultural and dietary habits caused by a nematode Trichinella spp. Human infection is acquired through ingestion of undercooked meat containing infective encysted larvae. There are two cycles of transmission, one domestic and the other wild. A complete life cycle develops in a single host harboring adult worms in the small intestine, from which newborn larvae migrate and finally encyst in striated muscle. Traumatic and immunological alterations are responsible for the main clinical features, including diarrhea, febrile syndrome, myalgias, oculopalpebral signs and eosinophilia. Cardiovascular, lung and CNS involvement characterize severe trichinosis. CNS inflammatory infiltration and damage may result from larval migration and vascular obstruction, or from the effect of toxic parasite antigens, or eosinophil infiltration. Humoral and cellular immune host response are relevant both to protect against re-infection and for immunodiagnosis. DNA probes and PCR technology may help to identify Trichinella spp. Muscle biopsy may disclose T spiralis larvae coiled within a muscle fibre host nurse cell surrounded by a capsule. Inflammatory infiltration includes monocytes, plasma cells, eosinophils and T lymphocytes mainly of the suppressor/cytotoxic phenotype. Histological appearance and histochemical profile of the host nurse cell differ from that of striated muscle fibre and are partly indicative of regeneration. Our own histological and histochemical findings in experimental studies of infected mouse muscle support the concept that changes induced by the larva encysting within a single host skeletal muscle fibre which becomes a nurse cell are unique of Trichinella infection. Interestingly, no dystrophin could be detected within the host nurse cell-capsule interface. It has been advanced that larva-induced host muscle fibre changes may be regulated at muscle gene transcription level whilst host regulatory pathways governed by cell cycle phase may also contribute to larval development.

Stem cell factor contributes to intestinal mucosal mast cell hyperplasia in rats infected with Nippostrongylus brasiliensis or Trichinella spiralis, but anti-stem cell factor treatment decreases parasite egg production during N brasiliensis infection.

We assessed the effects of the c-kit ligand, stem cell factor (SCF), in the jejunal mucosal mast cell hyperplasia that occurs during infection with the intestinal nematodes, Nippostrongylus brasiliensis or Trichinella spiralis in rats. Compared with vehicle-treated rats, rats treated with SCF (25 micrograms/kg/d, intravenous [i.v.] for 14 days) during N brasiliensis infection exhibited significantly higher levels of the rat mucosal mast cell (MMC)-associated protease, rat mast cell protease II (RMCP II) in the jejunum and serum on day 8 of infection, but not on days 10 or 15 of infection. By contrast, in comparison to rats treated with normal sheep IgG, rats treated with a polyclonal sheep antirat SCF antibody exhibited markedly decreased numbers of jejunal MMCs, levels of jejunal RMCP II, and serum concentrations of RMCP II during infection with either nematode, particularly at the earlier intervals of infection (< or = day 10). Taken together, these findings indicate that SCF importantly contributes to MMC hyperplasia and/or survival during N brasiliensis or T spiralis infection in rats, but that levels of endogenous SCF are adequate to sustain near maximal MMC hyperplasia during infection with these nematodes. Notably, treatment of rats with SCF somewhat increased, and treatment with anti-SCF significantly decreased, parasite egg production during N brasiliensis infection. This finding raises the interesting possibility that certain activities of intestinal MMCs may contribute to parasite fecundity during infection with this nematode.

[Current prevalence of trichinosis in Santiago, Chile (1992). A study on 500 corpses]. / Prevalencia actual de la triquinosis en Santiago, Chile (1992). Estudio en 500 cadáveres.

In August-December 1992, 500 diaphragm muscle samples taken at random from people who were autopsied at the Santiago Medico-Legal Service, were submitted to phototrichinoscopy to search for encysted larvae of Trichinella spiralis. For each sample seven small pieces were examined. Three hundred and eighty nine (77.8%) cadavers corresponded to males and one hundred and eleven (22.2%) to females. Ages ranged from 1 to 90 years. Ten (2.0%) of the individuals examined resulted positive, the higher frequencies corresponding to individuals over 20 years of age. The prevalence rate of T. spiralis infection found is rather similar to those detected in 1966-1967, 1972 and 1982, with percentages of 2.2, 3.4 and 2.8 respectively.

Triquinosis esporádica / Sporadic trichnosis

En el presente trabajo se analizan retrospectivamente las características clínicas y de laboratorio detectadas en 13 casos de triquinosis aguda esporádica, estudiados en el Instituto Nacional de Nutrición "Salvador Zubirán" (INNSZ) de 1977 a 1986. El número de casos por año fue de uno a dos con aumento a cinco en 1986; ningún paciente mostró correlación entre el tipo de dieta o sitio específico en la ciudad. La sintomatología fue similar a la descrita para la forma epidémica; en 69.1 por ciento de los casos se sospechó el diagnóstico en base clínicas y el 84.6 por ciento mostró eosinofilia. El motivo de la biópsia muscular fueron los síntomas musculares (92.3%) y corroboró la parasitosis en el 100 por ciento de los pacientes. El tratamiento fue tiabendazol y/o prednisona con mejoría en la mayoría de los pacientes durante su seguimiento (x: 7 meses). Se discute la utilidad de la biopsia muscular, las posibilidades de tratamiento y se enfatiza en los síntomas, signos y hallazgos de laboratorio de la triquinosis esporádica para sospechar dicha zoonosis ante un cuadro clínico de enfermedad inflamatoria multisistémica con síntomas musculares predominantes

[Sporadic trichinosis]. / Triquinosis esporádica.

A retrospective analysis was carried out to disclose the clinical and laboratory characteristics of 13 cases with sporadic trichinosis, proved by muscle biopsy at the "Salvador Zubirán" National Nutrition Institute and studied between 1977 and 1986. The number of cases per year was one or two with an increase to five in 1986. None of this patients showed a direct correlation between the type of diet or a specific area of the city. The clinical symptoms and physical findings were similar to those described previously for trichinosis, regardless of the clinical setting. In 69.1 percent of the cases the diagnosis was suspected based on clinical and physical data, and 84.6 percent had blood eosinophilia. Muscle biopsy was taken due to predominant muscular symptoms (92.3%) and this method was the most useful test to establish a specific diagnosis; no correlation was found between the number of larvae or cyst and the clinical symptoms. Thiabendazole and/or prednisone was administered and resulted in apparent improvement of the myopathy and blood eosinophilia during the follow-up (x: 7 months). A discussion is presented in relation to the usefulness of the muscle biopsy when a lack of specific enzyme tests exists; we emphasize the clinical manifestations and laboratory findings to suspect this zoonosis when a multisystemic inflammatory disease with striking myopathy is detected.

Diagnóstico retrospectivo de un brote de triquinosis en el Estado de Durango / Retrospective diagnosis of a trichinosis authebreake in the State of Durango

Al observar los sintomas de los enfermos de la epidemia de triquinosis de Nuevo Ideal se recordó que ocho meses antes ya se habían observado en el Hospital del IMSS en Durango casos semejantes, procedentes de una ciudad llamada Santiago Papasquiaro. La biopsia de músculo realizada en abril de 1982 a una de estas pacientes demonstró que era triquinosis lo que habían padecido. A propósito de esos casos se comentan sus síntomas y especialmente las manifestaciones oculares enfermedad

Triguinosis / Trichinosis

Se presenta un caso de triquinosis aguda en un masculino de 15 años de edad, el cual llamó la atención por la severidad de las manifestaciones clínicas, por la rapidez y facilidad del diagnóstico al utilizar biopsia de músculo y prueba de compresión, además de una buena respuesta a tiabendazol y dexametasona