Scielo RSS <![CDATA[Boletín chileno de parasitología]]> vol. 54 num. 3-4 lang. es <![CDATA[SciELO Logo]]> <![CDATA[El control de la hidatidosis]]> <![CDATA[The control of hydatidosis]]> <![CDATA[Seroprevalencia de la infección por Trypanosoma cruzi en escolares de seis y doce años de edad de tres departamentos endémicos de Uruguay]]> 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 schoolchildren from three departments: Artigas, Rivera and Tacuarembo. The whole sample included 4,722 schoolchildren, evaluated by the indirect inmunofluorescense (IFI) test for Chagas<FONT FACE=Symbol>¢</FONT> disease. The seroprevalence of T. cruzi infection in the six year-oldgroup 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. <![CDATA[Estudio de la respuesta inmune humoral en cerdos infectados con huevos y posoncosferas de Taeina solium]]> 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. <![CDATA[Tratamiento de quistes hidatícos hepáticos por aspiración percutánea e inyección de solución salina hipertónica: Resultados de un trabajo cooperativo]]> Percutaeous punctures-aspiration-injection-respiration (PAIR) of hydatid liver cysts, was performed in 38 patients 14-80 years old, with a total of 60 liver hydatid cysts. After aspiration under computed tomography guidance, hypertonic saline was injected into the cystic cavities of patients as a scolecidal agent. No major complications were associated with the procedures. In the follow-up period of 18 months, control CT scans of 35 cysts revealed a gradual decrease in cyst size with a mean volume reduction of 66%. Complications included two cases of urticaria, one case of anaphylaxis and one subcapsular hematoma. No mortality occurred. It is concluded that percutaneos aspiration and hypertonic saline injection for liver hydatid cysts appears to be an effective form of treatment and may eventually prove to be an alternative to surgical intervention. <![CDATA[Hidatidosis humana en Chile. Seroprevalencia y estimación del número de personas infectadas]]> 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 (June1999) 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, from 13,894 delivering mothers and 11,077 middle grade school children) 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 <![CDATA[Aspectos ecológicos de la relación parasitaria entre larvas de Contracaecum sp. (Nematoda, Anisakidae) y Serrasalmus spilopleura Kner, 1860 (Pisces, Characidae) en poblaciones naturales del nordeste argentino]]> From February 1987 to February 1989, the populational biology of Contraceacum sp. (larvae) in its paratenic host, the fish Serrasalmus spilopleura Kner,1860, was studied in two ponds in a subtropical permanent habitat northeastern of Argentina. Fishes from Ramada Paso pond presented 80% of prevalence and 1 to 132 larvae per fish while fishes from Aeroclub pond presented 63% of prevalence and 1 to 184 larvae per fish. Fishes collected from Aeroclub pond have shown a high prevalence of infection during the first period of study (1987), diminishing the following year. In fishes from Ramada Paso pond the prevalence varied not significatively during the two years. Prevalence and mean intensity of infection increase with body length and weigth of the hosts. Sex of hosts is not an influential factor in parasitic level. The lenitic "closed" environmental (Ramada Paso pond) evidenced the greatest larvae mean intensity and prevalence. Althougt, the lenitic"open" environmental (Aeroclub pond) showed the greatest parasitic number of individuals in an infrapopulation. The spatial dispersion in both ponds were agregated and fit well a negative binomial model. Neverthelees, the Aeroclub pond presented the greastest overdispersion. <![CDATA[Acaros del polvo de habitaciones enla ciudad de Punta Arenas, Chile]]> In medicine, the importance of mites in house dust gains importance from day to day. The close relation between these arthropods and man is the cause of a series of health problems such as allergic asthma, rhinitis and/or dermatitis. House dust samples were collected between January and December 1991 in Punta Arenas, city, Chile. Samples were processed by the <A HREF="#Artigas 1983">Artigas and Casanueva (1983)</A> technique, modified by Muñoz et al. (1983). The isolated specimens were subsequently identified using the <A HREF="#Artigas 1983">Artigas and Casnueva (1983)</A> pictorial key. Of the 134 samples studie, 29.1% presented one or more mite species. A total of 13 species were classified. Eight of them were registered for the city of Punta Arenas for the first time. Average weight of the dust analysed was 8.4 g. Mites were found from 0.2 g. onwards. A total of 1768 specimens was collected. The species more representative were: Blomia tjibodas (30.1%), Glycyphagus destructor (22.5%) and Tyrophagus putrescentiae (10.8%). The seasons that presented the higher proportions of mites were autumm (39.4%) and spring (37.1%). <![CDATA[Marcadores de riesgo para individuos con altas cargas de Ascaris lumbricoidesen una comunidad rural del Estado Cojedes, Venezuela]]> A total of 337 individuals from a rural community of Venezuela (Mapurite, Estado Cojedes) were 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 than10000 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 haemoglobine 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 <![CDATA[Tricocefalosis masiva en un adulto diagnosticada por colonoscopía]]> 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 cólonoscopy revealed an impressive and massive trichuriasis. The patient was succesfully 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 bidamount of Tricuris trichiura, fecal evacuations became nornal, geophagia disappeared and recovered 4 kg of body weight <![CDATA[Ectoparasitosis humanas: Estado actual en el Uruguay]]> The present status of human ectoparasitoses in Uruguay is analized with the main purpose of performing in the future, comparative studies in the region. After classifying ectoparasitores in temporaries and permanents, comments are made on particular clinical and epidemiological aspects of some of them. For remarking: the high prevalence of pediculosis capitis and scabies; the frequent observation of cutaneous myiasis by Dermatobia hominis with a very interesting modification of the geographical national distribution of the fly and the presence of an endemic area of creeping eruption by Ancylostoma braziliense and A. caninum in the north of the country. <![CDATA[Estandarización de la ELISA IgM e IgA para el inmunodiagnóstico de la triquinosis humana]]> An ELISA test for trichinosis using as antigen a larvae soluble fraction from Trichinella spiralis was carried out for the detection of IgMand 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, muliplied by a 1.2 factor was, considered the cut-off value. Criterion B was determinated 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, additional118 serum samples from individuals with other parasitoses, such as cysticercosis (18) hydatidosis (39), fascioliasis (12), toxocariasis (30), Chagas' disease(12) and individuals with non-specif 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 trichinosisis discussed. <![CDATA[Hidatidosis en la provincia de La Pampa, Argentina, 1998]]> Echinococcus granulosus es el agente causal de la hidatidosis clásica o equinococcosis quística. En América del Sur el ciclo mas extendido es el que involucra al perro y la oveja al existir condiciones ideales para la existencia del parásito. En la Provincia de La Pampa mantiene una presencia endémica con notificación de casos de infección humana y perros infectados con E. granulosus. En el presente trabajo de evalúa la prevalencia y distribución en el Departamento Maracó, Provincia de La Pampa. Perros de 36 establecimientos ganaderos fueron evaluados con bromhidrato de arecolina a la dosis de 3,5 mg/kg. En 27 establecimientos se detectó Taenia sp. y en tres E. granulosus. Se tomaron muestras de sangre de todos los habitantes de los estacimientos ganaderos las que fueron procesadas por enzimoinmunoensayo (ELISA). Asimismo, se efectuó un estudio retrospectivo sobre casos de hidatidosis tratados en el hospital de General Pico y dos clínicas privadas. Once casos humanos fueron tratados en período 96/97 (tasa deincidencia 6,79 x 100000). La Provincia de La Pampa parece mantener una presencia endémica con notificación de casos y perros infectados. A consecuencia de ello es de interés sanitario ampliar las investigaciones a otros departamentos provinciales a los efectos de delimitar el área endémica de distribución y organizar sistemas de vigilancia epidemiológica de la enfermedad.<hr/>Echinococcus granulosus is the agent that causes the classical hydatidosis or cystic echinoccosis. The most spread cycle in South America is the sheep-dog cycle, and offers favorable conditions for the development of the parasite. As the province of La Pampa shows an endemic presence with notification of cases and infected dogs, the present work has the aim of contributing to the study of the distribution and prevalence of the disease in the distritc of Maracó, La Pampa, Argentina. Dogs of 36 farms that had ovines, were dosed with arecoline hydrobromide at a dose of 3.5 mg/kg. Dogs from 27 (75%) farms resulted positive to Tenia sp. and 3 (8.3%) to E. granulosus. Blood samples were taken to all the people living in all the inquired farm and were processed by the ELISA test for hydatidosis. A retrospective survey on cases of human hydatidosis attended in the Hospital of General Pico, head if the sanitary region, and in two private clinics was performed. Analysis of clinical records indicated 11 cases operated during the period 1996/1997 (annual incidence rate of 6.8 x 100,000 inhabitants). It is of public health interest to fulfill epidemiologic investigations in other districts of the Province of La Pampa with the aim of delimitating the endemic distribution within the province and also organizing surveillance systems o human hydatidosis. <![CDATA[Brotes epizoóticos de triquinosis en dos criadores de cerdos de la Región Metropolitana, Chile.]]> 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 andto 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 1990-1994to 0.003 in 1995-1999. Between the end of June 1999 and middle January 2000 in MetropolitanRegion 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 Environmetal Health Service Abattoirs Progam carries out an epidemiological vigilance consisting in the follow-up of animls destined for slaughteringin order to initiate prophylactic actions oriented to eliminate eventual sources of trichinosis infection for human and rearing pigs <![CDATA[Redescription de Procamallanus mathurai (Camallanidae: Nematoda)]]> Procamallanus mathurai es redescrito y dibujado, sobre la basede un macho y diez hembras extraídas del estómago e intestino del pez de agua dulce Heteropneustes fossilis. La posición preecuatorial de la vulva no había sido descrita antes, el tamaño de las espículas difiere de la descripcion original<hr/>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 <A HREF="#Pande 1963">Pande et al., 1963</A> and it differs from the original description in the size of spicules.