COVID-19 y embarazo: caso clínico de presentación crítica, inflamación placentaria y transmisión vertical fetal demostrada / COVID-19 and pregnancy: clinical case of critical presentation, placental inflammation and demonstrated fetal vertical transmission

ANTECEDENTES: La pandemia global de COVID-19 llega al continente americano en marzo del año 2020 y en menos de dos meses reúne a más de la mitad de los casos a nivel global. OBJETIVO: Caso clínico de una mujer embarazada con una presentación crítica de COVID-19 y embarazo a las 25 semanas de gestación, en el contexto del peak de la pandemia en Chile en el otoño del año 2020. CASO CLÍNICO: El 20 de junio de 2020, una mujer de 34 años, con 25 semanas de embarazo, es trasladada desde Hospital de San Bernardo a Clínica Las Condes en Santiago, Chile, con un cuadro de 10 días de evolución de COVID-19, que evoluciona a una situación crítica con insuficiencia respiratoria severa. Ingresa a unidad de cuidados intensivos para ventilación mecánica. Las imágenes de radiología simple y de tomografía axial computarizada de tórax demuestran una neumopatía bilateral con imágenes características opacidades en vidrio esmerilado, asociado a engrosamiento intersticial, imágenes descritas previamente como características para COVID-19. La paciente permanece en unidad de cuidados intensivos en ventilación mecánica por siete días, con evolución favorable posterior, mejoría del cuadro séptico y alta después de 22 días de hospitalización. El parto ocurre en forma espontánea a las 38 semanas, la madre y el recién nacido evolucionan en buen estado general. El examen histopatológico placentario demuestra compromiso inflamatorio vellositario y los exámenes de anticuerpos en sangre del recién nacido demuestran la presencia de anticuerpos del tipo IgG e IgM. Se trata de uno de los pocos casos demostrados reportados de transmisión transplacentaria vía sanguínea de SARS-CoV-2 de la madre al recién nacido.

BACKGROUND: The global COVID-19 pandemic reaches the American continent in March 2020 and in less than two months it brings together more than half of the cases globally.OBJECTIVE: The clinical case of a 25-week pregnant woman with a critical presentation of COVID-19 and pregnancy at 25 weeks of gestation, is presented in the context of the peak of the pandemic in Chile in the fall of 2020. CLINICAL CASE: On June 20, 2020, a 34-year-old woman, 25 weeks pregnant, is transferred from Hospital de San Bernardo to Clinica Las Condes in Santiago, Chile, with a ten-day evolution of a COVID-19 that evolves to critical with severe respiratory failure. She is admitted to the intensive care unit for mechanical ventilation. Chest computerized axial tomography images demonstrate bilateral pneumopathy with characteristic images of ground-glass opacities, associated with interstitial thickening, images previously described as characteristics for COVID-19. The patient remains in the intensive care unit on mechanical ventilation for seven days, with subsequent favorable evolution, improvement of the septic condition, and discharge after 22 days of hospitalization. Delivery occurs at 38 weeks, the mother and the newborn evolve in good general condition. The placental histopathological examination demonstrates villous inflammatory involvement, and the newborn's blood tests show the presence of IgG and IgM antibodies. It is one of the few reported cases of transplacental transmission of SARS-CoV-2 from the mother to the newborn.

Estandarización de ELISA IgM e IgA para el inmunodiagnóstico de la triquinosis humana / Standarization of ELISA IgM and IgA for inmunodiagnosis of human trichinosis

An ELISA test for trichinosis using as antigen a larvae soluble fraction from trichinella spiralis was carried out for the detection of IgM and 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 tes 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 halthy 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 percent using serum dilution of 1:10, 1:100 and 1:500 respectively (criterion A) and 100,0, 97,8 and 95,6 percent for the same dilutions (criterion B), whereas the values for ELISA IgA were: 100,0 91,1 and 86,7 percent (criterion A) and 100,0 100,0 and 91,1 percent (criterion B). In order to find out the specificity of ELISA IgM and ELISA IgA, additional 118 serum samples from individuals with other parasitoses, such as cysticercoss (18) hydatidosis (39), fascioliasis (12), toxocariasis (30), Chagaïs disease (12) and individuals with non specif eosinophilia (7), were also tested. ELISA IgM presentes a specificity of 92,3, 93,4 and 97,3 percent (criterion A) and 96,2, 97,8 and 97,8 percent (criterion B) whereas the results for ELISA IgA were 97,8, 98,9 and 99,4 percent (criterion A) and 98,4 percent for the 1:10 and 1:100 dilutions and 100,0 percent for the 1:500 dilution (criterion B). The positive predictive values of ELISA IgM were 76,3, 77,8 and 88,1 percent (criterion A) and 86,5, 91,7 and 91,5 percent (criterion B) whereas the negative ones were 100,0, 98,3 and 95,7 percent (criterion A) and 100,0, 99,4 and 98,9 percent (criterion B). The positive predictive values of ELISA IgA were 91,8, 95,3 and 97,5 percent (criterion A) and 93,8, 93,8 and 100,0 percent (criterion B) whereas the negatives ones were: 100,0, 97,9 and 96,8 percent (criterion A) and 100,0, 100,0 and 97,8 percent (criterion B). The use of ELISA IgM and ELISA IgA in the inmunodiagnosis of trichinosis is discussed