Sensibilidad y especificidad de pruebas diagnósticas para CaCu: Muestras de mestizas y tarahumaras del Hospital General Salvador Zubirán de la ciudad de Chihuahua

El uso de metodologías combinadas para la detección de cáncer cérvico uterino (CaCu) mejora el grado de confianza de su diagnóstico. Los métodos de diagnóstico Papanicolaou, la colposcopia y el estándar de oro, que es el histológico, han ayudado a bajar la frecuencia de cáncer cervical invasivo. La valoración de estos métodos permite detectar correctamente a las mujeres enfermas de las sanas. En este estudio se calcula la sensibilidad y especificidad del Papanicolaou y colposcopia en una población mixta de mestizas y tarahumaras que acudieron a la Clínica de Displasias del Hospital General Salvador Zubirán de la ciudad de Chihuahua. Se observó diferencia significativa en los resultados del método colposcópico en la prevalencia de lesiones cervicales entre los dos grupos étnicos estudiados, con un mayor número de lesiones NIC I y cáncer en mestizas, y un mayor número de lesiones NIC II y III en tarahumaras. El resultado de sensibilidad en el Papanicolaou, considerando a la población total, fue de 53.3 %, menor que los resultados reportados por otros autores, sin embargo, se observó una buena especificidad del 87.5 %. Respecto a la colposcopia, obtuvimos un patrón similar, baja sensibilidad (55.5%) y alta especificidad (94.5%). Cuando analizamos los datos por etnias, los resultados del Papanicolaou se comportan en forma similar. Sin embargo, en los resultados de colposcopia en la población mestiza, la especificidad del método colposcópico fue del 97.5 %, y en la etnia tarahumara la sensibilidad de la colposcopia aumentó significativamente a 83.3%. Estas diferencias deben estar influidas por diversos factores, entre los más importantes, la experiencia de los médicos. Se considera esencial la vinculación entre el sector universitario y la Secretaría de Salud, ya que este tipo de análisis retroalimenta y permite llegar a la toma adecuada de decisiones durante las etapas de planeación de los programas de salud que intentan disminuir los índices de CaCu en nuestra población. Abstract Using a combination of methodologies to detect uterine cervical cancer increases the diagnosis confidence degrees. Papanicolaou, colposcopy and histological (gold standard), are the methods that have helped reduced the frequency of invasive cervical cancer. Validation of these methods allows correct detection, sick women versus healthy ones. We calculated sensitivity and specificity of Papanicolaou and colposcopy methods in a mixed population of mestizas and tarahumaras who attended to the Dispalsia Clinic at the Hospital General Salvador Zubirán from Chihuahua city. Prevalence of cervical lesions in mestizas were significantly different within colposcopic results, grater for NIC I and cancer, whereas NIC II and NIC III lesions were higher for tarahumaras. The results, including the whole women population showed a 53.3 % sensitivity in the Papanicolaou method, lower than other similar studies, however, the specificity was good (87.5 %). Regarding the colposcopy method, a similar result was observed, low sensitivity (55.5 %) and high specificity (94.5 %). Analyzing each ethnic group, the results were not so different regarding the Papanicolaou method, whereas in the colposcopy method in mestizas the specificity increased to 97.5 % and in tarahumaras the sensitivity increased significantly to 83.3 %. These differences must be influenced by several factors, maybe the most important being the medical doctor experience. We believe that interaction between the university and the Public Health Department is essential in order to analyze and feedback results that may help during planning activities to make good decisions that may decrease the cervical cancer in our population. Keywords: Prevalence, sensitivity, specificity, cervical cancer, Papanicolaou, colposcopy, histological

Comparative bionomics of four populations of Meccus longipennis (Hemiptera: Reduviidae: Triatominae) under laboratory conditions

The values of biological parameters related to the life cycles of four populations of Meccus longipennis (Reduviidae: Triatominae) were evaluated. Cohorts of each of the four studied populations from different geographical areas of Mexico were maintained under similar laboratory conditions and then compared. The population from El Saucito de Araujo was different from the other three studied populations, which could help explain the secondary importance of M. longipennis in the state of Chihuahua. This paper also supports the proposition that biological traits are important criteria for determining relationships between populations

The biology of three Mexican-American species of Triatominae (Hemiptera: Reduviidae): Triatoma recurva, Triatoma protracta and Triatoma rubida

The values of biological parameters related to hatching, lifespan, the number of blood meals between moults, mortality, time lapse before the beginning of feeding, feeding time and defecation delay for each instar of three Mexican-American species of Triatominae, Triatoma recurva, Triatoma protracta (former subspecies protracta) and Triatoma rubida (former subspecies uhleri), were evaluated and compared. No significant (p > 0.05) differences were recorded among the three species with respect to the average time required to hatch. This time was approximately 19 days. The average egg-to-adult development time was significantly (p < 0.05) shorter for T. rubida. The number of blood meals at each nymphal instar varied from one-five for each species. The mortality rates were higher for the first-instar nymphs of the three species studied. The mean time lapse before the beginning of feeding was between 0.3-3 min for most nymphs of all instars of each species studied. The mean feeding time was the longest for T. recurva, followed by T. protracta. The defecation delay was less than 10 min for T. recurva and T. rubida. Given these results, only T. rubida should be considered an important potential vector of Trypanosoma cruzi transmission to humans in areas of Mexico where these species exist, whereas T. recurva and T. protracta would be of secondary importance