Factores de riesgo socio-demográficos del síndrome cardiopulmonar por hantavirus / Sociodemographic risk factors of hantavirus cardiopulmonary syndrome

Resumen Introducción: El síndrome cardiopulmonar por hantavirus (SCPH) es causado en Chile y en el sur de Argentina por el Andes hantavirus (ANDV), el que es endémico en esta zona. La enfermedad causada por ANDV produce un aumento de permeabilidad vascular y filtración de plasma con una alta tasa de letalidad (35%), debido principalmente a insuficiencia respiratoria por edema pulmonar y al desarrollo en los casos graves de compromiso miocárdico, hipoperfusión y shock. Aunque se sabe que los factores socio-demográficos del hospedero pueden influir en el curso y el resultado de la enfermedad, estos no se han caracterizado previamente en la población chilena. Objetivo: Evaluar la relación entre los factores socio-demográficos y la gravedad del SCPH. Pacientes y Métodos: Período de análisis 2004-20013, pacientes atendidos en ocho centros colaboradores, diagnóstico etiológico serológico o por biología molecular, se comparan SCPH leve y grave. Se analizaron 139 pacientes chilenos, 64 (46%) con enfermedad grave, entre los cuales 12 murieron (19%). Resultados: La etnia europea tuvo un riesgo 5,1 veces mayor de desarrollar un SCPH grave que la etnia amerindia, gravedad mayor que también se asoció a una residencia urbana. Conclusiones: Se observó una asociación estadísticamente significativa entre etnia, lugar de residencia y evolución de SCPH. Se discuten hipótesis que expliquen estos hallazgos.

Background: Hantavirus cardiopulmonary syndrome (HCPS) is caused by new world hantaviruses, among which Andes hantavirus (ANDV) is endemic to Chile and Southern Argentina. The disease caused by ANDV produces plasma leakage leading to enhanced vascular permeability and has a high case fatality rate (35%), mainly due to respiratory failure, pulmonary edema and myocardial dysfunction, hypoperfusion and shock. Host sociodemographic and genetic factors might influence the course and outcome of the disease. Yet, they have not been thoroughly characterized. Aim: To evaluate sociodemographic factors as risk factors in severity of HCPS. Patients and Methods: Study period: 2004-20013, attending in eight collaborative centers, etiological diagnosis was performed by serology or molecular biology, mild and severe HCPS were compared.139 Chilean patients were analyzed, 64 (46%) with severe disease among which 12 (19 %) died. Results: European ethnicity had 5,1 times higher risk than Amerindian ethnic group to develop a severe HCPS, greater seriousness that was also associated with an urban residence. Conclusion: It was observed that ethnicity and type of residence were significant risk factors for HCPS severity. Hypotheses explaining these findings are discussed.

Hantavirosis: Caracterización clínica-epidemiológica de pacientes pediátricos en Chile / Hantavirosis: Clinical and epidemiological characteristics of pediatric patients in Chile

Background: The first cases of Hantavirus cardiopulmonary syndrome in children were described in the United States and represented 8 percent of the total reported cases; in Chile, the proportion of pediatric cases represents 15 percent of all national cases. Aim: To describe the epidemiology and clinical course of 82 children reported to the Chilean Ministry of Health up to 2007 and to characterize more extensively a subgroup of 24 children whose detailed clinical data were available. Results: Forty patients were under 10 years old. Seventeen (17/82) of 82 cases (20.7 percent) presented in the context of a family cluster. Ninety eight percent of cases (80/82) occurred among individuals living in rural areas and 66 percent during summer months). The overall fatality rate was 36.6 percent. Fever (93 percent), respiratory distress (75 percent) and gastrointestinal symptoms (75 percent) were the most frequent symptoms encountered in the 28 children studied more extensively. Abnormal blood coagulation test were significantly associated with death while an increased hematocrit was associated with severe cases (hemodynamic unstability). Conclusion: An early diagnosis should favor early onset of aggressive treatment that could potentially save lives. Increasing knowledge on the clinical presentation of the disease in children should improve early clinical diagnosis among health care professionals.

Introducción: Los primeros casos del síndrome cardiopulmonar por hantavirus en población pediátrica fueron descritos en Estados Unidos de América y representaron 8 por cientoo de los casos comunicados; en Chile la frecuencia relativa en niños ha sido de 15 por ciento del total nacional. Objetivo: Describir la epidemiología y evolución clínica de 82 niños notificados al MTNSAL hasta el 2007 y caracterizar el comportamiento clínico en 24 de ellos de quienes se disponía de registro clínico detallado. Resultados: Cuarenta pacientes tenían bajo 10 años de edad, predominando envarones. Un quinto (17/82) estuvo asociado a conglomerados familiares. Noventay ocho por ciento (80/82) se presentaron en áreas rurales y 54 (66 por ciento) ocurrieron en el verano. La letalidad fue de 36,6 por ciento. Los síntomas más frecuentes fueron: fiebre (93 por ciento), dificultad respiratoria (75 por ciento) y síntomas gastrointestinales (75 por ciento). De los exámenes de laboratorio con significancia estadística, las pruebas de coagulación alteradas predicen fallecimiento y el hematocrito elevado está siempre presente en pacientes graves. Conclusión: El diagnóstico oportuno facilita el tratamiento intensivo precoz. La difusión de la presentación clínica infantil mejorará la sospecha diagnóstica en el personal de salud.

Listeria monocytogenes: informe de un aumento de casos en mujeres embarazadas y revisión de la literatura / Listeria monocytogenes: report of a rise in pregnant women and literature review

Listeria monocytogenes, rare pathogen in the general population, causes serious infections in patients at the extreme ages of life, pregnant woman, and those with immunosuppression. The clinical manifestations are essential to suspect the disease in patients at risk, allowing an early prescription of antimicrobial therapy, before the results of the cultures are available. Clinical course and prognosis depends on how early treatment is started and, in pregnant women, the gestational age. In Clínica Alemana, at Santiago, we detected a 15 fold rate rise of neonatal listeriosis between year 2007 and 2008. Ten cases were diagnosed between January and July 2008 and the seven cases occurring in pregnant women are reported here. All these patients were in their first pregnancy, which could be associated with similar lifestyle and food habits. Considering this new epidemiological scenario, it is important to educate the population, and to conduct an epidemiological study in order to determine the national situation of Listeria monocytogenes infection.

Listeria monocytogenes, es un patógeno poco frecuente en la población general, causante de infecciones graves en pacientes en edades extremas de la vida, mujeres embarazadas e inmunodeprimidos. La sospecha de la enfermedad en pacientes de riesgo se basa principalmente en el cuadro clínico, lo que permite iniciar un tratamiento empírico antes de contar con los resultados de los cultivos. La evolución y pronóstico dependen de la precocidad con que se inicia la terapia y de la edad gestacional. En Clínica Alemana de Santiago detectamos un aumento de 15 veces en la tasa de listeriosis comparando el año 2007 con el 2008. Entre enero y julio 2008, se diagnosticaron 10 casos, de los cuales siete fueron en primigestas, lo que podría tener relación con un hábito alimentario y características de vida similar. Es fundamental, a la vista de esta nueva realidad epidemiológica, educar a la población en hábitos alimentarios y de higiene, como también realizar un estudio epidemiológico que determine la situación nacional de infección por L. monocytogenes.

Susceptibilidad genética a hantavirus Andes: Asociación entre la expresión clínica de la infección y alelos del sistema HLA en pacientes chilenos / Genetic susceptibility to Andes Hantavirus: Association between severity of disease and HLA alíeles in Chilean patients

En Chile, la infección por hantavirus Andes (ANDV) tiene una expresión clínica variable, reconociéndose diversos grados de severidad. El presente estudio se realizó con el objeto de analizar la posible asociación entre la constitución genética de pacientes chilenos para el sistema HLA y la expresión clínica de la infección por ANDV. Se analizaron los alelos HLA A, B, DRB1 y DQB1, en dos grupos de pacientes con infección por ANDV: 41 pacientes con evolución clínica leve (sin insuficiencia respiratoria severa y sin requerimientos de ventilación mecánica) y 46 pacientes con evolución clínica grave (con insuficiencia respiratoria grave y/o shock). La determinación molecular del sistema HLA se realizó mediante SSP-PCR. El alelo HLA DRB1 * 15, se encontró en una frecuencia significativamente más alta en los pacientes leves (p = 0,007). Por lo tanto, el alelo DRB 1*15 se asociaría al curso clínico leve de la enfermedad. El alelo HLA-B*08, se encontró en una frecuencia mayor en los pacientes graves, la diferencia alcanzó una significación estadística marginal (p = 0,06). Así, el alelo HLA-B*08, podría estar asociado al curso clínico grave de síndrome cardiopulmonar ocasionado por hantavirus Andes.

Andes hantavirus (ANDV) infection in Chile has a variable clinical expression, and infected individuals may present with different grades of disease severity. This study aimed to determine if clinical expression of ANDV infection in Chilean patients is associated with the HLA system. HLA alíeles A, B, DRB1 and DQB1, were studied in two groups of patients with confirmed ANDV infection: 41 patients with a mild disease course (without respiratory failure and cardiovascular shock) and 46 patients with a severe disease course (with respiratory failure and shock). Molecular typing of HLA system was performed by SSP-PCR. The HLA-DRB 1*15 alíele, was significantly more common in the group of patients with mild disease (p = 0,007) and thus for possibly associated with a protective effect against ANDV infection. Conversely, HLA-B*08 was more common in patients with severe disease (p = 0,06). Although the association was marginally significant, alíele HLA-B*08 may be linked to an increased susceptibility to the severe clinical course of HCPS by ANDV.

Prevalencia de anticuerpos contra Bartonella henselae en niños, en adolescentes y en una población de riesgo ocupacional en Chile / Prevalence of Bartonella henselae antibodies in Chilean children, adolescents and veterinary workers

Background: Bartonella henselae is the causative agent of cat-scratch disease. Aim: To study the seroepidemiology of Bartonella henselae in healthy Chilean children and in a population with occupational risk. Material and methods: Serum IgG antibodies were determined by indirect fluorescence technique in 181 children and adolescents and in 107 technical and professional workers involved in the care of cats. Samples with titers equal to or greater than 64 were considered positive. Results: Twenty four (13.3%) children and 11 (10.3%) occupational risk subjects were seropositive. No significant differences by age and gender were observed. Conclusions: Assuming that seroprevalence indicates level of exposure to Bartonella henselae, these results suggest that this infection is endemic in Chile and, for this reason, the best antibody titer to diagnose acute cat-scratch disease should be higher than the figure recommended by the Centers for Disease Control in the in United States.

Presencia de Bartonella henselae en gatos: cuantificación del reservorio natural y riesgo de exposición humana de esta zoonosis en Chile / Presence of Bartonella henselae in cats, in Chile

Background: The availability of a serologic test for cat scratch disease in humans has allowed the diagnosis of an increasing number of cases of this disease in Chile. Aim: To perform a serological survey for Bartonella henselae among cats in Chile. Material and methods: Blood samples from 187 cats living in three Chilean cities were obtained. IgG antibodies againts Bartonella henselae were measured using indirect immunofluorescence. Blood cultures were done in 60 samples. The presence of Bartonella henselae in positive cultures was confirmed by restriction fragment length polymorphism polimerase chain reaction (RFLP-PCR). Results: The general prevalence of IgG antibodies against Bartonella henselae was 85.6%. No differences in this prevalence were found among cats younger or older than 1 year, or those infested or not infested with fleas. However domestic cats had a lower prevalence when compared with stray cats (73 and 90% respectively, p <0.01). Bartonella henselae was isolated in 41% of blood cultures. All the isolated were confirmed as Bartonella henselae by RFLP-PCR. Conclusions: This study found an important reservoir of Bartonella henselae in Chilean cats and therefore a high risk of exposure in humans who have contact with them.