Malaria en Chile: 1913-2001 / Malaria in Chile from 1913 to 2001

Background: Malaria was restricted to the I Region of Chile, being Anopheles pseudopunctipennis the only vector species. In 1936 the parasitosis affected more than 50 percent of the population and 62.4 percent of military recruits, proceeding from Southern regions became infected. From 1937 to 1947, an antimalaria campaign was carried out, stressing actions on the battle against the vector and the treatment of malaria infected individuals. Since April 1945 no autochthonous cases of malaria have been detected. Aim: To update the situation of malaria in Chile. Methods: 1) Imported malaria: Analysis of occasional publications on the subject (1945-1988) and the annual reports of the Ministry of Health Department of Epidemiology (1990-2001). Annual reports on the Anopheles specimens collected -mostly larvae- in the provinces of Arica and Iquique and examined in the Parasitology Unit of the School of Medicine, University of Chile, during the period 1980-2001. Results: 1) Imported malaria. A total of 24 cases were published in the period 1945-1988. In the 1980-2001 period, the Ministry of Health recorded 66 cases with 5 (8.8 percent) deaths. 2) Anophelines: Only in 1984, 1985, 1998 and 2001 A. pseudopunctipennis foci were detected. Entomological surveillance was stressed and insecticides were applied on these focuses. Conclusions: Autochthonous malaria does not exist in Chile since 1945. The detection of malaria cases in countries where the parasitosis was eradicated, can be the result of tourism or migrations. In Chile, the Environmental Programs of Arica and Iquique perform periodical surveys in localities where mosquitoes exist. When A. pseudopunctipennis is found, the entomological vigilance is stressed and insecticide applications are reiterated until the situation is controlled

Loxoscelismo en pediatría: Región Metropolitana Chile / Loxoscelism in paediatrics: Región Metropolitana Chile

Loxoscelismo es el cuadro tóxico producido por veneno que arañas del género Loxosceles L. Iaeta, en Chile, inyectan en el momento de la mordedura. Puede presentarse en dos formas clínica: loxoscelismo cutáneo-visceral (LCV). El objetivo del presente trabajo es exponer y analizar los aspectos clínico-epidemiológicos de 56 casos pediátrico -38 LC y 18 LCV- atendidos en la Región Metropolitana. En los últimos 45 años se ha encontrado una mayor incidencia de ambas formas en primavera-verano, en dormitorios cuando el niño dormía o se estaba vistiendo, siendo las áreas cutáneas más frecuentemente afectadas las extremidades y cara, con sensación de lancetazo urente como síntoma inicial. Manifestaciones clínicas más frecuentes: dolor, edema y placa livedoide que derivó a escara necrótica. Manifestaciones clínicas del LCV fueron hematuria, hemoglobinuria, ictericia, fiebre y compromiso de conciencia; letalidad 22,2 por ciento. El LCV no tuvo relación con el sitio de mordedura, extensión de la lesión local ni época del año. Si el compromiso visceral no aparece en las primeras 24 h es muy probable que se trate de un LC cuyo pronóstico es bueno. Si el paciente con LCV ha sobrepasado las 48 h, sus posibilidades de recuperación son altas. El tratamiento fue parental: antihistamínicos o corticoides en LC y corticoides en LCV. Conclusiones: En esta serie se observa una predominancia en el sexo femenino, sin diferencias estacionales ni de edad. En su gran mayoría los casos se originaron en el domicilio, afectando en especial las extremidades. El LCV fue más frecuente en mujeres, y sus principales manifestaciones fueron la hematuria y hemoglobinuria, y la precocidad del diagnóstico y su manejo son factores fundamentales en el pronóstico

Estudio comparativo de la sensibilidad y mortalidad de las ninfas III y IV de triatoma infestans usadas en el xenodiagnóstico de pacientes chagásicos crónicos / Comparative study on sensivity and mortality of triatoma infestans nymphs III and IV used in the xenodiagnosis of chronic chagasic patients

Triatoma infestans nymphs have shown a good sensitivity for detecting trypanosoma cruzi in the bood stream of infected hosts when are used in the xenodiagnosis (XD). This method, with its natural limitations, using seven nymphs III of T. infestans, has been routinely utilized with a satisfactory yield. With the aim of an eventual improving of the yield of XD (with 7 nymphs), two series of 54 XD boxes each, containing a total of 378 nymphs III and 378 nymphs IV respectively, were applied one of each during three consecutive days to nine chronic chagasic patients. Each of the nymphs was weighted before an after the application of the boxes, and the intestinal content of them was examined 30, 60 and 90 days later. The main comparative results obtained with nymphs III and IV of T. infestans were: blood ingestion 40 versus 107 mg (2,7 higher), positivity of insects 35,8 percent versus 50,6 percent (15,8 percent higher), positivity of XD boxes (7 nymphs each) 46,3 percent versus 55,6 percent (9,3 percent higher), and mortality rates 28,6 percent versus 12,2 percent (16,4 percent lower). All these results demonstrate that nymphs IV of T. infestans, because their higher capacity of ingesting blood and higher tolerance to examination manipulations, are more suitable for been used in XD

Comparación de la infección por trypanosoma cruzi en niños menores de 10 años de la V Región Chile: 1982-1995 / Comparison of trypanosoma cruzi infection in less than 10 year old children from the V Región Chile: 1982-1995

Evaluation of desinsectation programs carried out in the two health services from the V region, was undertaken by comparing serologic prevalences of T. cruzi infection age groups exposed to the risk of infection in rural areas during the antivectorial campaign activities (1982 vs 1995). Thus, were studied 2,193 blood samples from children under 10 years of age, proceeding from six chagasic endemic provinces in which antitriatomic domiciliary insecticide sprayings had been performed. Indirect hemagglutination and ELISA tests were carried out to each of the blood samples. A total de 42 (1,9 percent) children resulted positive. As an five counties no positive cases were detected in the last five years it is possible to assume that vector trasmission of T. cruzi should have been interrupted in them. When comparing prevalences existing in 1982 with the present ones, it is possible to observe a 63,5 percent of reduction of transmission in the V region, been this reduction higher in the Aconcagua Health services with 79,6 percent and lower in the Viña del Mar - Quillota Health Service with 55,6 percent. According to these results, comparison of prevalence of T. cruzi infection in children less than 10 year old in diverse periods, allows evaluate the vectorial control of Triatoma infestans programs

Hidatidosis en Chile: seroprevalencia y estimación del número de personas infectadas / Human hydatidosis in Chile: seroprevalence and an estimate of the number of infected people

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 percent 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 (test 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 percent of diagnosed hydatidosis with hydatid cysts in many different locations, was an autopsy finding

Estudio longitudinal, mediante el xenodiagnóstico, de la parasitemia en pacientes con infección por trypanosoma cruzi crónica / Longitudinal study, by means of xenodiagnosis, of parasitemia in patients with chronic trypanosoma cruzi infection

A 2-5 years follow-up of parasitemia, by the use of xenodiagnosis (XD) was carried out in nine patients with chronic T. cruzi infection who proceeded from chagasic endemic areas of Chile. The patients (mean age 55 years) were hospitalized in the chronic section of a psychiatry institution sited in a permanent triatomines free urban area. Clinical examination, x-rays images (cardiovascular, esophagus and colon) and electrocardiogram resulted normal in all the patients. Basic study unit of parasitemia was a XD box which contained 7 nymphs III of triatoma infestans which was used in a serial XD consisting in the simultaneous application of a pair of boxes a day during three consecutive days, making a total of six boxes (42 nymphs). The minimal time of duration of infection (MDI.) for each patient was estimated that this was adquired close to hospitalization. The MDI. varied between 6 and 45 years. The global positivity of XD boxes ranged between 6.3 and 84.7 percent, being three patients lower than 12 percent and six patients higher than 52 percent. In considering the yield of XD it is important to stress that during all the study of the mine patients with chronic chagasic infection 1282 XD boxes were applied resulting positive 582 (45,4 percent). At the end of the follow-up all patients received specific treatment for chagasic infection with nifurtimox at the daily dose of 10 mg/kg of body weight during 60 days. According to the result, two main conclusions arise: 1.- serial XD has a hight efficiency for detecting, evaluate and evolve parasitemia in patients with chronic chagasic infection. 2.- parasitemia may present low, medium or high levels in different individuals and has a variable and fluctuating character

Presencia de triatoma spinolai en viviendas humanas / Presence of triatoma spinolai in human dwellings

Triatoma spinolai is a wild species of triatomine existing exclusively in Chile, with scarce epidemological importance in the transmission of trypanosoma cruzi to man. It has been found in enviroments from 3000 meters down to the sea level. Excepcionally it has been found in human dwellings. In order to clarify the possibility of an adaptation of T. spinolai to human dwellings a study was undertaken in 50 rural-periurban dwellings from regions III, IV, V and metropolitan in which this triatomine was found. The dwellings were clasiffied in houses (35) and huts (15). The insects was trapped in 35 dwellings (24 houses and 11 huts) located in declivities (70 for percent) and 15 dwellings (14 and 1) located in plains. This proportion is significantly higher than the average of 26,2 for percent for dwellings located in declivities. It is concluded tahat presence of T. spinolai in dwellings, more than a triatomine invasion is the result of the construction of huts or houses in the insect habitat

Epidemiología de la enfermedad de Chagas en Chile: frecuencia de infección humana por trypanosoma cruzi por grupos de edad y por regiones / Epidemiology of Chagas's disease in Chile: frequency of trypanosoma cruzi human infection by age groups and regions

Chagas's disease is endemic in rural-periurban sections of the northern half of Chile which includes the first seven political-administrative regions of the country (18º30'-34º36' South lat.). Data concerning to the results of an indirect hemagglutination test for Chagas's disease performed to 15,418 rural-periurban and 45,119 urban inhabitants from the chagasic endemic regions are presented migrations from rural-periurban to urban areas have contributed to the dissemination of trypanosoma cruzi infection. General rates of infection for rural-periurban (r-p) and urban (u) sections were 16,7 for percent and 1,9 for percent respectively. The higher prevalence rates were detected in region III with 27,2 for percent (r-p) and 3,9 (u) and Region IV with 24,7 for percent (r-p) and 3,5 for percent (u), while the lower prevalence rates corresponded to Region VI with 7,0 for percent (r-p) and 0,8 for percent (u). Serological positivity increased parallelly with age in all regions

Evaluación de un programa de erradicación del triatoma infestans en viviendas rurales de la IV Región de Chile mediante serología para la enfermedad de Chagas en niños de 0 a 10 años de edad / Triatoma infestans eradication program assessment in rural dwellings from the IV Region of Chile by serology for Chagas' disease in children 0 to 10 years of age

The present study deals with the evaluation of the effectiveness of the measures employed in the control of triatoma infestans, the vector of trypanosoma cruzi infection (Chagas' disease), in the IV Region of Chile through a serological follow up program. For this reason, a serological survey has been carried out in 2,783 chidren, from 0 to 10 years, who live in rural high endemic areas of the region. The sera were tested using an indirect hemagglutination test (IHAT) and ELISA techniques with results agreeing in 99,9 for percent of the samples. In children with positive serology xenodiagnosis was perfomed and blood samples from the corresponding mothers were submitted to serology for Chagas's disease. These addicional tests should allow to distinguish between congenital infection and vectorial transmission. It was observed that vectorial transmission of T. cruzi was interrupted in some localities where entomological control has been applied for 10 years, or lowered in those which have been submitted to desinsectations in the last 5 years. On the other hand, a relatively high prevalence of the infection has been detected in some localities. These results suggest an apparent increase of vectorial transmision, indicating the need of readjusting the dwellings insecticide sprayings activities to improve the measures against the vector

Positividad del xenodiagnóstico según edad en personas con serología positiva para enfermedad de Chagas / Positive xenodiagnosis according to age in people with seropositive Chagas's disease

An analytical study of positive xerodiagnosis (XD), according age distribution, in people with a positive indirect hemagglutination test (IHAT) for Chagas's disease has been carried out. A total of 1,137 IHAT for Chagas's disease positive persons were submitted to two wooden XD boxes containing 7 triatoma infestans nymphs III each. The positivity in percentage of XD in the different age groups was: 0-9 year old (60,8), 10-19 (35,8), 20-29 (31,5), 30-39 (28,7), 40-49 (30,0), 50-59 (34,3) and ò 60 (43,3). The 60,8 positivy of XD in children under 10 years of age is possibly due to the rather recent trypanosoma cruzi infection in this age group and to diverse inmunological mechanisms, which decrease with the age increasing

Comparación de la frecuencia de alteraciones electrocardiográficas en grupos de personas aparentemente sanas con serología positiva para enfermedad de Chagas, para toxoplasmosis o para ambas parasitosis / Comparison of the frequence of electrocardiographical alterations in groups of apparently healthy persons with positive serology for Chagas'disease, for toxoplasmosis or for both parasitoses

Comparison of the frequence of electrocardiographical alterations in groups of apparently helathy persons with positive serology for Chagas disease, for toxoplasmosis or for both parasitoses

Infección chagásica en donantes de sangre de hospitales de las regiones endémicas de Chile (1982-1987): transcendencia epidemiológica del problema / Chagasic infection in blood donors from hospitals in endemic regions of Chile (1982-1987). Epidemiological transcendence of the problem

La enfermedad de Chagas, producida por el Trypanosoma cruzi y transmitida por triatominos hematófagos, existe en América desde el sur de Estados Unidos hasta Chile y Argentina. Existe en sectores rurales y periurbanos de la mitad norte de Chile, siendo su prevalencia del 16,9%. Constantes migraciones rural-urbanas han contribuído a su propagación hacia sectores urbanos. Para investigar el impacto de dichas migraciones sobre la población susceptible de donar sangre y el probable incremento del riesgo de transmisión del T. cruzi vía transfusional se efectuaron encuestas seroepidemiológicas en donantes de 22 hospitales de la mitad norte de Chile. Mediante la reacción de hemaglutinación indirecta se examinaron 16.841 donantes encontrándose un 2,7% de positividad, porcentaje que permitió estimar que habría 126.477 potenciales donantes de sangre infectados por T. cruzi en los sectores urbanos estudiados. Estos hechos refuerzan la necesidad que en bancos de sangre de las regiones endémicas del país se efectúe rutinariamente serología para enfermedad de Chagas, para adoptar o reforzar medidas preventivas pertinentes