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

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