BACKGROUND Vector transmission of Trypanosoma cruzi appears to be interrupted in Chile; however, data show increasing incidence of Chagas' disease, raising concerns that there may be a reemerging problem. OBJECTIVE To estimate the actual risk in a changing world it is necessary to consider the historical vector distribution and correlate this distribution with the presence of cases and climate change. METHODS Potential distribution models of Triatoma infestans and Chagas disease were performed using Maxent, a machine-learning method. FINDINGS Climate change appears to play a major role in the reemergence of Chagas' disease and T. infestans in Chile. The distribution of both T. infestans and Chagas' disease correlated with maximum temperature, and the precipitation during the driest month. The overlap of Chagas' disease and T. infestans distribution areas was high. The distribution of T. infestans, under two global change scenarios, showed a minimal reduction tendency in suitable areas. MAIN CONCLUSION The impact of temperature and precipitation on the distribution of T. infestans, as shown by the models, indicates the need for aggressive control efforts; the current control measures, including T. infestans control campaigns, should be maintained with the same intensity as they have at present, avoiding sylvatic foci, intrusions, and recolonisation of human dwellings.

Chagas disease remains highly prevalent in Chile, especially between the regions of Arica and Parinacota, and Coquimbo. Since 1999 it is considered that in Chile the vector transmission was interrupted. Under this premise, the epidemiological dynamics should be changing. We analyzed the evolution of the prevalence of Chagas’ disease analyzing 64,995 xenodiagnosis performed in the laboratory of Parasitology of the Faculty of Medicine of the University of Chile between 1949 and 2014. The evolution of the mortalities and incidences from the databases of the Ministry of Health in the periods in which it was analyzed. The rates of domiciliary infestation and the number of vector insects sent to the Public Health Institute and its trypano-triatomine indices were also analyzed. The prevalence of Chagas’ disease in inhabitants of risk areas remained stable in this period as well as mortality. The incidence rate shows a progressive increase with a tendency towards stabilization. A significant decrease in sampling effort was found, declining by two orders of magnitude, especially since 2000. The progressive increase in morbidity had no clear relation to the interruption of the vector chain nor to the greater diagnostic effort occurred in 2009, since it was evident from before. While home infestation declines, reports of intrusion of solitary individuals and wild foci of T. infestans have increased. Trypano-triatomine indices were maintained with high values in all vector species. This study shows a worrying situation, for while on the one hand the interruption of the vector transmission and improvement in the research systems is emphasized, the concern for this disease seems to be decreasing with less diagnostic efforts and lower education at the higher level, and by the other hand the numbers show that the problem if it is not increasing, at least maintains its careless historical magnitude.

Resumen Introducción: La enfermedad de Chagas sigue siendo altamente prevalente en Chile, especialmente entre las regiones de Arica y Parinacota y de Coquimbo. Desde 1999 se considera que en Chile se encuentra interrumpida la transmisión vectorial. Bajo esta premisa, la dinámica epidemiológica se debiera estar modificando. Objetivo: Analizar la evolución temporal de la enfermedad de Chagas en Chile Material y Métodos: Analizamos la evolución de la prevalencia de la enfermedad de Chagas a través del análisis de resultados de 64.995 xenodiagnós-ticos realizados en el laboratorio de Parasitología de la Facultad de Medicina de la Universidad de Chile, entre 1949 y 2014. Se estudió la evolución de las mortalidades e incidencias disponibles en las bases de datos del Ministerio de Salud en los períodos en que fue posible. Se analizaron las tasas de infestación domiciliaria y el número de insectos vectores enviados al Instituto de Salud Pública y sus índices tripano-tratominos. Resultados: La prevalencia de la enfermedad de Chagas en habitantes de zonas de riesgo se mantuvo estable en este período, al igual que la mortalidad. La tasa de incidencia muestra un incremento progresivo con tendencia a la estabilización. Se encontró un significativo decrecimiento del esfuerzo de muestreo, decayendo dos órdenes de magnitud, especialmente desde 2000. El aumento progresivo de la morbilidad no tiene clara relación con el corte de la cadena vectorial ni con el mayor esfuerzo diagnóstico ocurrido en 2009, ya que era evidente desde antes. Mientras que la infestación domiciliaria disminuye, han aumentado los reportes de intromisión de individuos solitarios y los focos silvestres de T. infestans. Los índices tripano triatominos se mantienen con valores altos en todas las especies vectores. Discusión: Este estudio muestra una situación preocupante, ya que mientras por una parte se destaca el corte de la transmisión vectorial y mejora en los sistemas de pesquisa, la preocupación por esta enfermedad parece ir decreciendo con menores esfuerzos diagnósticos y menor enseñanza a nivel superior, y por otra parte los números muestran que el problema si es que no está aumentando, al menos mantiene su descuidada magnitud histórica.

Human fascioliasis is a parasitic zoonosis that affects the liver of human and herbivorous animals. In chronic cases, its diagnosis is confirmed by direct visualization of parasitic eggs in stool examination, by positive testing for Fasciola hepatica antigens in stools, or by direct observation of parasites by endoscopic retrograde cholangiography or surgery. In acute cases, serological reactions as immunoblothing or detection of parasite antigens in the blood are useful. The treatment of choice is triclabendazole. However, parasite resistance in animals, as well as in man, has been reported to this drug. We report four patients in whom the parasitic infection persisted despite a course of treatment with triclabendazole.

We evaluate the elimination of the microscopic stage of conventional xenodiagnosis (XD) to optimize the parasitological diagnosis of Trypanosoma cruzi in chronic Chagas disease. To this purpose we applied under informed consent two XD cages to 150 Chilean chronic chagasic patients. The fecal samples (FS) of the triatomines at 30, 60 and 90 days post feeding were divided into two parts: in one a microscopic search for mobile trypomastigote and/or epimastigote forms was performed. In the other part, DNA extraction-purification for PCR directed to the conserved region of kDNA minicircles of trypanosomes (PCR-XD), without previous microscopic observation was done. An XD was considered positive when at least one mobile T. cruzi parasite in any one of three periods of incubation was observed, whereas PCR-XD was considered positive when the 330 bp band specific for T. cruzi was detected. 25 of 26 cases with positive conventional XD were PCR-XD positive (concordance 96.2%), whereas 85 of 124 cases with negative conventional XD were positive by PCR-XD (68.5%). Human chromosome 12 detected by Real-time PCR used as exogenous internal control of PCR-XD reaction allowed to discounting of PCR inhibition and false negative in 40 cases with negative PCR-XD. Conclusion: PCR-XD performed without previous microscopic observation is a useful tool for detection of viable parasites with higher efficiency then conventional XD.

Congenital Chagas disease acquired special importance in Chile after the certification of the control of Triatoma infestans and transmission by blood donors affected with Trypanosoma cruzi. In order to establish adequate protocols for intervention and control in infected mother-neonate pairs in endemic zones of Chagas disease, we present partial results (2005-2008) of a pilot project which is being carried out in the Province of Choapa, IV Region, Chile, whose objectives are: determine the current prevalence of the disease in pregnant women, estimate the incidence of vertical transmission of T. cruzi to newborns, determine the lineages of the parasite present in mothers who do and do not transmit the disease, determine the prevalence of Chagas disease in maternal grandmothers of neonates and study placental histopathology. Preliminary results indicated that in this study period, 3.7% of the women who gave birth in the Province have Chagas disease and 2.5% of their newborns were infected. The most frequent T. cruzi genotypes found in mothers studied during pregnancy were TCI and TCIId, either alone or in mixed infections. A high percentage (74.3%) of the grandmothers studied was infected with the parasite. In 29 placentas from mothers with Chagas disease we observed edema, necrosis, fibrinoid deposits and slight lymphoplasmocyte infiltration. In three placentas we found erythroblastosis and in one of them amastigote forms of T. cruzi; this was one of the cases of congenital infection. The evaluation of the diagnostic and control protocols generated will allow us to determine if it has been possible to modify the natural history of vertical transmission of T. cruzi in Chile.

Divers inquires established by chagasic patients in relation to its clinical condition, motivated to a group of parasitologists to design an assistance educative programme. 72 volunteer patients participated, 32 men and 40 women from the high and low chagasic endemic zones of Chile. The educative methodology basically consist in the application of a diagnosis and acquired knowledge tests; theorical sessions of six relationated tematics subjects, tutorial practical activities; use of audiovisual and printed material, personal diligence by a parasitological doctor (after the educative assistance and with the serological, electrocardiographical and parasitological antecedents determinated previously) and evaluation of the educative activity by the patients. A greater previous and acquired knowledge was observed in chronic chagasics patients from endemic zones. All of them demonstrated a high degree of interest and actively participated in the programmed activities. The used methodology, the tutorial work of small groups and the individual attention-orientator by the parasitological doctor, facilitated the teaching-learning process. It is concludes that the educative assistance answer many of the inquires in relation to the disease, allows the patient to recognize the role as protagonist of his own comfort and transforms him in an efficient agent to control Chagas disease

Las diversas inquietudes planteadas por pacientes chagásicos crónicos en relación a su condición clínica, motivaron a un grupo de parasitólogos a diseñar un programa de intervención educativa. Participaron en forma voluntaria 72 pacientes, 32 hombres y 40 mujeres, procedentes de zona de alta y baja endemia chagásica de Chile. La metodología docente consistió fundamentalmente en: aplicación de test diagnóstico y de conocimientos adquiridos; sesiones teóricas que abordaron seis temáticas relacionadas; actividades prácticas tutoriales; utilización de material audiovisual e impreso; atención personalizada por médico parasitólogo (posterior a la intervención educativa y con los antecedentes serológicos, electrocardiográficos y parasitológicos previamente determinados) y evaluación de la actividad educativa por parte de los pacientes. Un mayor conocimiento previo y adquirido se observó en chagásicos crónicos procedentes de zonas endémicas. Todos demos-traron un alto grado de interés y participaron activamente de las actividades programadas. La metodología utilizada, el trabajo tutorial de pequeño grupo y la atención-orientación individual por parte del médico parasitólogo, facilitaron el proceso de enseñanza-aprendizaje. Se concluye que la intervención educativa responde a muchas de las interrogantes respecto de la afección, permite al paciente reconocer el rol que le cabe como protagonista de su propio bienestar y lo transforma en un eficaz agente en el control de la enfermedad de Chagas

A familiar outbrake of strongyloidosis affected peruvian immigrants who had arrived Chile in november 2001 is reported. In march 2002, Strongyloides stercoralis infection of the index individual was confirmed by the Basic-Clinical Laboratory of Parasitology of the Faculty of Medicine of the University of Chile, in Santiago, Chile. At the Roberto del Río Pediatric Hospital, a 11 years old girl presenting juvenil rheumatoid arthritis and mild abdominal distress was studied. A serial of three stool samples was collected and procesed by ether-centrifugal concentration technique. A plentiful quantity of rhabditoid larvae of S. stercoralis was observed. To detect larvae in the faeces and specific serum antibodies against S. stercoralis by means of ELISA her parents and sister were studied. The mother of the index case and her sister were positive in both test. The father was not infected. The three positive cases were treated with Ivermectine. A control study performed one year later demonstrated a positive ELISA test only in the sister

Se presenta un brote familiar de stron-gyloidosis que afectó a inmigrantes peruanos que habían llegado a Chile en noviembre del año 2001. En marzo del 2002, se confirmó en el Laboratorio de Parasitología Básico-Clínico de la Facultad de Medicina de la Universidad de Chile que el caso índice presentaba infección por Strongyloides stercoralis. Correspondía a una menor de 11 años que estaba siendo estudiada en el Hospital Roberto del Río por artritis reumatoide juvenil. Además de esta patología la niña refería leves molestias abdominales, siendo derivada a nuestra unidad, donde se le efectuó un examen parasitológico seriado de deposiciones (EPSD), observándose abundantes larvas rabditoides de S. stercoralis, por lo cual se procedió a estudiar al grupo familiar integrado por los padres y una hermana. A todos ellos se les efectuó EPSD e inmunodiagnóstico mediante ELISA para detectar anticuerpos anti S.stercoralis. Resultaron positivos para ambos exámenes la madre y las dos hijas. El padre fue negativo. Se decidió tratar con ivermectina y controlar los resultados del tratamiento anti-parasitario al grupo familiar al cabo de un año. Después de ese periodo permanecía positiva serológicamente, solamente la hermana del caso índice debido a que no ingirió los medicamentos de la manera indicada

We report a 51 years old, woman, who live in a rural zone of Llolleo, San Antonio, V Región of Chile. Her dewelling is near a wheat ground sown. In november 1999 during the cleaning of her house she felt a "bug" in her head, but did not find it. She started immediatly with itching, hypoesthesia of arms and legs, dispnea, thoracic pain, vomiting, 40ºC fever, myalgias in right arm, thorax, and hypogastric zone, trembling, plantiful sweating, and rapidly lost consciousness. She recovered consciousness 1 hour later and asked for help. A neighbour saw and captured a spider going out of her clothes. She was taken to the emergency room, where she received sera and oxigen, and was discharged two days later with a prescription of antihistaminics, glucosteroids, a muscle relaxing agend and diuretics. During six months se was controled in the out patient clinic of the hospital. The spider was identified by entomologist as Latrodectus mactans. In june 2002 when she was sleeping, felt a wounding lancet pain in the middle finger of the right hand. Afterwards a black plate with yellow vesicles in his center appeared in that same zone. The right arm become edematous and paresthetic; the patient complained of an important asthenia. She was hospitalized receiving intravenous steroids. In this ocassion the patients couldn´t keep the spider, but when she describes it to the entomologist of the National Science and Arqueological Museum of San Antonio, the specimen was identified as an exemplar of Loxosceles laeta. Latrodectism is usually a day out door accident, during agricultural activities. Loxoscelism is in general a night in door accident. In this excepcional case the patient lives near a wheat ground sown and the absence of routinary cleaning of her dewelling, could explain both accidents. We could´nt find publications of accidents of both spiders affecting the same person. For this reason we consider important to comunicate this case

Background: Cellular immune mechanisms of the resistance to infection by T cruzi as well as the pathogenesis of Chagas disease are still controversial. Aim: To quantify and analyse the peripheral blood immune cells from chagasic and non chagasic patients by flow cytometry. Patients and methods: Peripheral blood samples were taken from 21 individuals seropositive for Chagas disease, under no specific treatment. Control samples from 21 healthy blood donors were also obtained. To quantify immune cells populations by flow cytometry, antibodies against CD3, CD4, CD8, CD16/56, CD45/14, CD19 and HLA-DR markers were used. Results: The percentage of CD8+ cells was low and the CD4+/CD8+ ratio was high in chagasic patients, compared to their non infected counterparts. No statistically significant differences in the number of CD4+, NK, B, CD4+HLADR+ and CD8+HLADR+ cells, were observed within the two groups. Conclusions: These results show that Chilean chronic chagasic patients have lower percentage of CD8+ cells and higher CD4+/CD8+ ratio than non infected individuals (Rev Méd Chile 2002; 130: 363-367

Woman of 39 years of age from Talca province (VII Region) who presented intense abdominal pain which was interpreted as an acute abdomen, and an exploratory laparotomy was performed, wich was not concludent. After different procedures and tests the diagnosis of acute fasciolosis was achieved. She was treated with triclabendazole.

From 1997 to 1999, we identified seven human cases of infection by fourth stage larvae of Pseudoterranova decipiens in Chile. All identified larvae were coughed up by the patients. Subjects were 10-55 years old; five were female. Some patients complained of coughing, expectoration, pharyngeal pain, nausea or anal and nasal pruritus. Larvae of three patients were coughed up from 36 h to 7 days after having eaten raw (cebiche or sushi) or lightly fried fish. P. decipiens has a marine life cycle. Infective third stage larva develop to adult stage in pinniped mammals. The nematode eggs are voided with the host faeces and develop and hatch releasing third stage larvae. Some crustaceans and fish act as hosts of third stage larvae. Man is an accidental host for third or fourth stage larvae.

A chilean family traveled to Cuba and to a rainforest region in Panamá. At return to Chile they presented with painful erythematous swollen skin papules along their dorsum and thighs. The diagnosis of foruncular myiasis was made after identifying larvae of Dermatobia hominis by morphology. Three of the patients healed 2 days after surgical removal of the larvae and one of them healed after two weeks.

Se presentan cuatro casos de myiasis forunculosa en un grupo familiar que viajó a Cuba y a regiones selváticas de Panamá. A su regreso a Chile, notaron lesiones cutáneas solevantadas, eritematosas y dolorosas, en cuyo interior se encontraron larvas de mosca de Dermatobia hominis, confirmadas por estudio morfológico. El tratamiento consistió en la extracción quirúrgica o manual de las larvas complementada con tratamiento antibiótico. Uno de los pacientes evolucionó tórpidamente y tres restantes favorablemente.

Two cases of hepatic fascioliasis which simulated hepatic tumors are presented: Patient 1. (42-year-old woman), presented pain in the epigastric and right hypochondrium. US, CAT and MNR suggested a cholangiocarcinoma. She was operated on by practicing hepatic segmentectomy, cholecystectomy and closign of a cholecystogastric fistula. The extirpated hepatic segment presented a tumoral aspect, but its histopathological study revealed numerous granulomas, some of them with F. hepatica eggs and others with Charcot - Leyden crystals. ELISA and complement fixation reaction for fascioliasis resulted positive. Search of F. hepatica eggs in stools was negative. The patient was treated with triclabendazole. Patient 2. (58-year-old woman) also presented pains in the upper hemiabdomen. Hypereosinophilia (32%). Abdominal CAT showed multiple hipondense irregular zones suggesting infiltrative processes in the liver right lobe. The hepatic biopsy, under CAT, eventhough lead to think in a hamartoma, a diagnosis of chronic cholangitis compatible with a parasitic etiology raised. ELISA and complement fixation reaction for fascioliasis were positive. Coproparasitological exams for F. Hapatica resulted negative. She was successfully treated with triclabendazole. Hapatic fascioliasis simulates numerous diseases, among them hepatic tumors.

In 1999, the examination of clinical files of Barros Luco Trudeau Hospital, allow as to investigate 40 cases with megacolon, fecaloma, intestinal obstruction or achalasia as main out go diagnosis. Only in one case of megacolon inquired in 1999 chagasic ethiology was confirmed by serology. The low incidence in this group, is caused by the fact that this hospital attend persons of zones of low chagasic endemia, with mistakes in the registers and lack of clinical suspicious

La revisión de fichas clínicas del año 1999 en el Hospital Barros Luco Trudeau, permitió pesquisar 40 casos con diagnóstico principal al egreso de megacolon, fecaloma, obstrucción intestinal o acalasia. En un solo caso de megacolon pesquisado ese año, se confirmó la etiología chagásica mediante serología convencional anti-Trypanosoma cruzi. La baja incidencia en esta casuística es debida a que este servicio hospitalario es una zona de baja endemia chagásica, a falencias en los registros y a la falta de sospecha clínica