In the Yucatan Peninsula, Mexico, localized cutaneous leishmaniasis (LCL) caused by Leishmania (Leishmania) mexicana is a typical wild zoonosis restricted to the forest, and humans are only accidentally involved. The transmission of L. (L.) mexicana has been related to the patient's occupation: "chicleros"(gum collectors) and agricultural workers. The objective of this study was to document L. (L.) mexicana seasonally of transmission in endemic areas of LCL in the state of Campeche, Yucatan Peninsula, Mexico. The timing of incidence of LCL in humans during 1993-1994, as well as the rate and time of infection in rodents and sand flies between February 1993 and March 1995 were analyzed. Rodents and sand flies were found infected between November and March, when men carried out their field activities and are exposed. Based on results analyzed, it is concluded that L. (L.) mexicana in the endemic area of LCL in the state of Campeche, Yucatan Peninsula, Mexico, presents a seasonal transmission restricted to the months of November to March. The knowledge of the timing of the transmission cycle in an endemic area of leishmaniasis is very important because intervention measures on the high-risk focus and population might be restricted.
De febrero a junio de 1994 se realizó en la ciudad de Mérida, Yucatán, México, una encuesta para determinar la prevalencia de asma y la frecuencia de antecedentes familiares del padecimiento en niños de edad escolar. Se estudió una muestra aleatoria de 505 niños de 6 a 12 años de edad, de ambos sexos, alumnos de las escuelas de educación primaria del área urbana de Mérida. Se administró una encuesta al padre o a la madre del niño. Se preguntó si el niño había padecido repetidas veces respiración ruidosa con dificultad respiratoria y silbidos, si había padecido bronquitis, bronquitis asmatiforme o asma, y si la madre, el padre o alguno de los hermanos había padecido asma. En total se encontraron 61 niños asmáticos (prevalencia acumulada, 12%), en los cuales los antecedentes maternos o paternos de asma fueron más frecuentes (25 y 18%, respectivamente) que en los demás niños (10 y 6%, respectivamente), siendo la diferencia estadísticamente significativa (P < 0,002) en ambos casos. Los resultados muestran la alta prevalencia de asma en Mérida y sugieren la participación de la herencia en el desarrollo de la enfermedad.
A survey was conducted in Merida, Yucatan, between February and June 1994 in order to determine the prevalence of asthma and the frequency of a family history of the disease in school-age children. A random sample was taken of 505 children of both sexes between the ages of 6 and 12 who were enrolled in elementary schools in the urban area of Merida. Every child's father or mother was surveyed and asked if the child had had recurrent episodes of loud, difficult breathing with wheezing chest sounds, if he or she had had bronchitis, asthmatiform bronchitis, or asthma, and if the mother, father, or any of the siblings had ever suffered from asthma. A total of 61 children with asthma (cumulative prevalence, 12%) was found. Among these children a history of maternal or paternal asthma was more frequent (25 and 18%, respectively) than in other children (10 and 6%, respectively), the difference being statistically significant (P < 0,002) in both cases. Results show the high prevalence of asthma in Merida and suggest that heredity plays a role in the development of the disease.