Boletin chileno de parasitologia最新文献

Due to the importance of cysticercosis in Mexico and Latin America and to the fact that in the last years another mechanism of infection for this disease has been proposed, i.e. through postoncospheres and immunosuppression of the host, we have considered relevant to perform the present work, which consisted in assessing the immune response induced by dexamethasone as well as that produced by parasites in pigs infected with T. solium eggs, or postoncosphere-infected, and in postoncosphere-infected and dexamethasone-treated animals. We used 10 recently weaned pigs, three were used as controls, two of them without the drug and one with it; two were infected with T. solium eggs; five with postoncospheres receiving also dexamethasone three of them. We evaluated the humoral response against parasite antigen using indirect haemagglutination (IH) and ELISA methods. Results of the immune humoral response revealed titres of up to 1:128 in T. solium eggs infected animals, of 1:16 in postoncosphere infected animals, and of 1:32 towards the end of the experiment in postoncosphere plus dexamethasone animals. Absorbance titres with ELISA confirmed these findings. Data obtained by IH show that the antibody titres of the pigs challenged with postoncospheres and postoncospheres plus dexamethasone are positive as compared to the titres obtained in the pigs infected with T. solium eggs. Results from the ELISA confirmed this finding, since, from weeks 14 to 17, the pigs became positive, behaving as those pigs that developed cysticercosis. This is relevant as it indicates that the antiposcosphere antibodies recognized antigens of T. solium larvae.

An ELISA test for trichinosis using as antigen a larvae soluble fraction from Trichinella spiralis was carried out for the detection of IgM and IgA specific antibodies in 45 serum samples from patients confirmed or suspected to have trichinosis by strong clinical and epidemiological evidences. All the patients had positive serology detected by precipitin test, bentonite floculation test, indirect hemagglutination test and ELISA IgG test. The cut-off value was determined using two criteria. Criterion A was determined in each plate, using three positive controls and two negative ones; the average of the negative controls and the weakest positive control, multiplied by a 1.2 factor was, considered the cut-off value. Criterion B was determined using the average plus three standard deviations from 64 apparently healthy persons serum samples. In both cases, three serum dilutions (1:10, 1:100 and 1:500) were used. The sensitivity of ELISA IgM was 100.0, 93.3 and 82.2% using serum dilutions of 1:10, 1:100 and 1:500 respectively (criterion A) and 100.0, 97.8 and 95.6% for the same dilutions (criterion B), whereas the values for ELISA IgA were: 100.0, 91.1 and 86.7% (criterion A) and 100.0, 100.0 and 91.1% (criterion B). In order to find out the specificity of ELISA IgM and ELISA IgA, additional 118 serum samples from individuals with other parasitoses, such as cysticercosis (18) hydatidosis (39), fascioliasis (12), toxocariasis (30), Chagas' disease (12) and individuals with non-specific eosinophilia (7), were also tested. ELISA IgM presented a specificity of 92.3, 93.4 and 97.3% (criterion A) and 96.2, 97.8 and 97.8% (criterion B) whereas the results for ELISA IgA were 97.8, 98.9 and 99.4% (criterion A) and 98.4% for the 1:10 and 1:100 dilutions and 100.0% for the 1:500 dilution (criterion B). The positive predictive values of ELISA IgM were 76.3, 77.8 and 88.1% (criterion A) and 86.5, 91.7 and 91.5% (criterion B) whereas the negative ones were 100.0, 98.3 and 95.7% (criterion A) and 100.0, 99.4 and 98.9% (criterion B). The positive predictive values of ELISA IgA were 91.8, 95.3 and 97.5% (criterion A) and 93.8, 93.8 and 100.0% (criterion B) whereas the negatives ones were: 100.0, 97.8 and 96.8% (criterion A) and 100.0, 100.0 and 97.8% (criterion B). The use of ELISA IgM and ELISA IgA in the immunodiagnosis of trichinosis is discussed.

In Chile swine trichinosis has presented a progressive decreasing in the last two decades of XX century. T. spiralis pig infection descended from an average of 0.683 per 1000 in 1980-1984 to 0.315 in 1985-1989 and to 0.115 in 1990-1996. In the particular case of Metropolitan Region this decreasing has been more marked: from an average of 0.058 per 1000 in 1990-1994 to 0.003 in 1995-1999. Between the end of June 1999 and middle January 2000 in Metropolitan Region abattoirs T. spiralis was detected in 15 (4.9%) out of 306 swine from two pigsties located in El Monte (E.M.) and Padre Hurtado (P.H.) 45 and 30 km south-west from Santiago. In the same period another four pigs from the same premises were found infected in abattoirs of other regions. During inspection visits it was stated that both pig farms had deficient sanitary conditions. Phototrichinoscopy was positive in three out of five Rattus norvegicus collected in E.M. In pigsty PH the examination of diaphragm samples of 25 dogs and 17 cats resulted negative. In the premises originating T. spirali infected swine the Metropolitan Environmental Health Service Abattoirs Program carries out an epidemiological vigilance consisting in the follow-up of animals destined for slaughtering in order to initiate prophylactic actions oriented to eliminate eventual sources of trichinosis infection for human and rearing pigs.

A total of 337 individuals from a rural community of Venezuela (Mapurite, Estado Cojedes) was studied. Stoll faecal examination was carried out and the total number of A. lumbricoides was recovered after the treatment of the individuals sampled with Pyrantel pamoate at a dose of 10 mg/kg body weight in children and 15 mg/kg in adults. A relationship between the high worm burden condition (individuals excreting more than 10,000 epg of A. lumbricoides) and the age of the hosts was found. Resulting with the major values of relative risk index (Rr) the 5-9 years old class (Rr = 3.2 t = 3.4). This relationship was not found between high worm burden condition (HWB) and the sex of the hosts. The following individuals have the the highest possibilities to become HWB: with blood group A (Rr = 3.05 t = 4.08), with haemoglobin type HbA HbS (Rr = 1.86 t = 2.13), individuals with the combinations A HbA HbF (Rr = 3.46 t = 2.31) and A HbA HbS (Rr = 3.11 t = 2.78). It was estimated that the selective treatment of the total HWB detected (72) with an effective product, determined a reduction of 95.4% of the environmental contamination with de eggs and 72.3% of the worm burden.

A case of massive trichuriasis in a 37-year-old female from a rural locality of the Metropolitan Region of Chile, with antecedents of alcoholism, chronic hepatic damage and portal cavernomatosis, is presented. Since 12 year ago she has had geophagia. In the last six months she has frequently presented liquid diarrhea, colic abdominal pains, tenesmus and sensation of abdominal distention. Clinical and laboratory tests confirmed her hepatic affection associated with a celiac disease with anemia and hypereosinophilia. Within a week diarrhea became worse and dysentery appeared. A colonoscopy revealed an impressive and massive trichuriasis. The patient was successfully treated with two cures of 200 mg tablets of mebendazole twice daily for three days with a week interval. After the first cure she evacuated a big amount of Tricuris trichiura, fecal evacuations became normal, geophagia disappeared and recovered 4 kg of body weight.

Chile is located in the southwestern border of South America. The country is 4,329 km long and 96-342 wide. From north to south it is divided into five marked different biogeographical zones: deserts, steppes, bushes, forests (cattle raising) and austral (sheep raising). Population (June 1999) 15,017,760 (14.6% rural). Human hydatidosis is endemic in Chile. According to Ministry of Health information about 320 cases are registered each year. In order to find out the likely prevalence of human hydatidosis in Chile, a series of serosurveys was carried out in 1988-1997 throughout the total country. By using the indirect hemagglutination reaction and ELISA for hydatidosis (tests with good sensibility and specificity) 60,790 unselected apparently healthy persons: 41,399 from urban areas (16,428 blood donors, 13,894 delivering mothers and 11,077 middle grade schoolchildren) and 19,361 from rural areas--from randomly selected family groupings--were studied. A total individuals 82 (136/100,000) resulted positive: 36 (87/100,000) urban and 46 (241/100,000) rural, being the prevalence higher in rural areas, particularly in the southern austral zone (mean 1068/100,00). These figures agree with those observed in clinical epidemiological studies. In conformity with the present results, in the whole country 17,002 individuals should have hydatidosis: 10,318 urban and 6,784 rural. All these possible infected people, not necessarily should present pathology in the future, as it has been observed in autopsies from unselected individuals, performed at the Medico-Legal Service in Santiago, in whom 71.3% of diagnosed hydatosis with hydatid cysts in many different locations, was an autopsy finding.

The present species, identified as Procamallanus mathurai obtained from the stomach and intestine of fresh water fish Heteropneuste fossilis (Bloch) is redescribed. Position of vulva preequatorial which was not described earlier by Pande et al., 1963 and it differs from the original description in the size of spicules.

The last national survey on seroprevalence of T. cruzi human infection in Uruguay, showed a 3.4% in adults from endemic areas. Since 1983, antivectorial actions of the control program have been carried out continually. In consequence, household infestation by Triatoma infestan, the main vector of T. cruzi in Uruguay, decreased in all endemic areas and was completely eliminated in some of them. The objectives of the present work are to evaluate the new seroepidemiological situation. A representative sampling of rural and urban population was undertaken, to include six and twelve year-old school children from three departments: Artigas, Rivera and Tacuarembo. The whole sample included 4,722 school children, evaluated by the indirect immunofluorescence (IFI) test for Chagaś disease. The seroprevalence of T. cruzi infection in the six year-old group was 0.3% in Artigas, 0.6% in Rivera and 1.0% in Tacuarembo. The seropositive children with seropositive mothers support the possible congenital transmission.