Novel prevention program for trichinellosis in inuit communities.
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Repeated outbreaks of trichinellosis caused by the consumption of Trichinella-infected walrus (Odobenus rosmarus) meat, which have sometimes led to serious morbidity, have stimulated Inuit communities in Nunavik (northern Quebec), Canada, to develop an innovative trichinellosis prevention program. The program involves preconsumption testing of meat samples from harvested walrus at a regional laboratory and the rapid dissemination of the results of such testing to communities. Local health authorities in Inukjuak conducted an epidemiological investigation after testing identified Trichinella-positive walrus meat in September 1997. This report describes the events that occurred before, during, and after the trichinellosis outbreak and also documents how the prevention program contributed to successful resolution of the outbreak. (+info)
The immune mechanism which expels the intestinal stage of Trichinella spiralis from rats.
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The immunological response of rats to the intestinal phase of Trichinella spiralis was assessed using criteria derived from pervious studies with the nematode Nippostrongylus brasiliensis in rats and mice. In adult rats, the duration of infection with either parasite is similar and both infections are prolonged in young and lactating rats. As previously shown with N. brasiliensis, immunity to T. spiralis was transferred to recipients with antiserum or mesenteric lymph node cells from immune donors and antisera and cells given in combination had an additive effect. Signs of damage similar to that caused by antibodies in N. brasiliensis appeared in T. spiralis adult worms as the infection progressed and this damage occurred earlier in animals given antiserum or cells. On the basis of these results, it is concluded that the immunological control of adult T. spiralis requires both antibodies and cells, but the relative importance of these components and the way in which they affect T. spiralis requires further analysis. (+info)
Evaluation of a digestion assay and determination of sample size and tissue for the reliable detection of Trichinella larvae in walrus meat.
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A digestion assay was validated for the detection of Trichinella larvae in walrus (Odobenus rosmarus) meat, and appropriate samples for testing were determined using tissues from infected walruses harvested for food. Examination of muscles from 3 walruses showed that the tongue consistently contained approximately 2-6 times more larvae than the pectoral and intercostal muscles. Comparison of numbers of larvae in the root, body, and apex of the tongue from 3 walruses failed to identify a predilection site within the tongue, but the apex was considered an optimal tissue because of the high larval density within the tongue and the ease of collection. All 31 spiked samples weighing 50 g each and containing between 0.1 and 0.4 larvae per gram (lpg) were correctly identified as infected, indicating that the sensitivity of this procedure is adequate for diagnostic use. A sample size of 10 g consistently detected larvae in 2 walrus tongues containing > or = 0.3 lpg (n = 40), and until additional data are available, sample sizes from individual walrus tongues should be a minimum of 10 g. This study provides the preliminary data that were used for the development of a food safety analytical protocol for the detection of Trichinella in walrus meat in arctic communities. (+info)
Short report: Human infection with Trichinella britovi in Granada, Spain.
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An outbreak of trichinellosis caused by ingestion of pork infected with Trichinella britovi occurred in the province of Granada in southern Spain in April-May 2000. Thirty-eight people were affected and 15 of them were hospitalized at the University Hospital of San Cecilio (Granada). The probable source of infection was sausage made from uninspected wild boar meat and inspected pork. Ninety-two percent of the patients had myalgias, 47.6% had diarrhea and/or vomited, 78.6% had periorbital edema, and 76.0% had fever. Twenty-two patients (15 hospitalized and 7 nonhospitalized) were serologically studied. Eosinophil levels were less than 5% of the total leukocyte count in 86.7% of the patients. Levels of creatinine phosphokinase (range = 200-2,213 U/L) and lactate dehydrogenase (range = 560-7,558 U/L) were elevated in 85.7% and 78.6% of the patients, respectively. Sixteen (72.7%) and 20 (90.9%) patients were positive for T. britovi by indirect immunofluorescence and Western blot, respectively. (+info)
An outbreak of trichinellosis due to consumption of bear meat infected with Trichinella nativa, in 2 northern Saskatchewan communities.
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In June 2000, bear meat infected with Trichinella nativa was consumed by 78 individuals in 2 northern Saskatchewan communities. Interviews and blood collections were performed on exposed individuals at the onset of the outbreak and 7 weeks later. All exposed individuals were treated with mebendazole or albendazole, and symptomatic patients received prednisone. Confirmed cases were more likely to have consumed dried meat, rather than boiled meat (P<.001). Seventy-four percent of patients completed the recommended therapy, and 87% of patients who were followed up in August 2000 reported complete resolution of symptoms. This outbreak of trichinellosis was caused by consumption of inadequately cooked bear meat contaminated with T. nativa. Apart from clinical symptomatology, blood counts, creatine kinase levels, serology test results, and analysis of the remaining bear meat helped establish the diagnosis. Treatment with antiparasitic drugs and prednisone was beneficial in limiting the severity and duration of the illness. (+info)
Analysis of a 43-kDa glycoprotein from the intracellular parasitic nematode Trichinella spiralis.
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The L1 larvae of the parasitic nematode Trichinella spiralis invade skeletal muscle and initiate a process that has been interpreted to represent skeletal muscle dedifferentiation. In this process, the infected region of the muscle cell is converted into a unique structure, called the Nurse cell. The nematode T. spiralis can survive for tens of years within the cytoplasm of the Nurse cell and secretes proteins into the cytoplasm that are believed to play a role in mediating the Nurse cell formation or maintenance. We have cloned a cDNA encoding the T. spiralis-derived, 43-kDa secreted protein. Structural analysis of the predicted 344-amino acid sequence revealed an N terminally located signal peptide and a potential helix-loop-helix motif in the main body of the protein. Antibodies raised against the 43-kDa recombinant protein were used in immunocytolocalizations of T. spiralis-infected skeletal muscle sections. These antibodies strongly stained the Nurse cell nuclei and the nematode itself. Specific, though slightly weaker staining also occurred in the Nurse cell cytoplasm. In Western blots, the antibodies react with the 43-kDa protein but also detected at least two other T. spiralis-secreted proteins. DNA hybridizations reveal at least one additional 43-kDa-related sequence encoded in the T. spiralis genome. We conclude that either the 43-kDa protein and/or a closely related 43-kDa family member is secreted into the muscle and translocates to the muscle-derived nuclei. This model may provide insights into the mechanisms involved in Nurse cell formation. (+info)
PROBLEM/CONDITION: Trichinellosis is a parasitic disease caused by tissue-dwelling roundworms of the species Trichinella spiralis. The organism is acquired by eating Trichinella-infected meat products. The disease has variable clinical manifestations, ranging from asymptomatic to fatal. In the United States, trichinellosis has caused hundreds of preventable cases of illness and occasional deaths. The national trichinellosis surveillance system has documented a steady decline in the reported incidence of this disease, as well as a change in its epidemiology. REPORTING PERIOD COVERED: This report summarizes surveillance data for trichinellosis in the United States for 1997-2001. DESCRIPTION OF SYSTEM: Trichinellosis became a nationally reportable disease in 1966, but statistics have been kept on the disease since 1947. The national trichinellosis surveillance system is a passive system that relies on existing resources at the local, state, and federal levels. Cases are diagnosed based on clinical history with laboratory confirmation. Cases are reported weekly to CDC through the National Electronic Telecommunications System for Surveillance (NETSS). Detailed data regarding signs and symptoms, diagnostic tests, and food consumption are gathered by using a supplementary standardized surveillance form and are reported to CDC by fax or mail. This information is compared with NETSS data several times a year by CDC staff. Discrepancies are reviewed with the state health departments. The purpose of the surveillance system is to determine the incidence of trichinellosis, to maintain awareness of the disease, to monitor epidemiologic changes, to identify outbreaks, to guide prevention efforts, and to measure the effectiveness of those efforts. RESULTS: Although trichinellosis was associated historically with eating Trichinella-infected pork from domesticated sources, wild game meat was the most common source of infection during 1997-2001. During this 5-year period, 72 cases were reported to CDC. Of these, 31 (43%) cases were associated with eating wild game: 29 with bear meat, one with cougar meat, and one with wild boar meat. In comparison, only 12 (17%) cases were associated with eating commercial pork products, including four cases traced to a foreign source. Nine (13%) cases were associated with eating noncommercial pork from home-raised or direct-from-farm swine where U.S. commercial pork production industry standards and Regulations do not apply. INTERPRETATIONS: The majority of the decline in reported trichinellosis cases is a result of improved observance of standards and regulations in the U.S. commercial pork industry, which has altered animal husbandry practices resulting in reduced Trichinella prevalence among swine. PUBLIC HEALTH ACTIONS: Because of the change in epidemiology of trichinellosis and the continued occurrence of cases among consumers of wild game meat and noncommercial pork, more targeted public education is needed to further reduce the incidence of this disease. (+info)
Trichinellosis associated with bear meat--New York and Tennessee, 2003.
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Trichinellosis is a parasitic infection caused by tissue-dwelling Trichinella roundworms and is associated traditionally with ingestion of pork from infected domestic swine. As a result of improvements in swine production, trichinellosis has declined steadily in the United States. However, infection also can result from eating the meat of wild animals. During 1997-2001, a total of 72 cases of trichinellosis (median: 12 cases annually; range: 11-23 cases) were reported to CDC; the majority of these infections were associated with eating wild game, predominantly bear. This report describes three cases of trichinellosis associated with eating undercooked bear meat reported from New York and Tennessee in 2003. To prevent trichinellosis, persons should cook meat, particularly wild game, to an internal temperature of 160 degrees F (71 degrees C). (+info)