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.

Sandflies attracted by human bait were caught in an endemic focus of localized cutaneous leishmaniasis in the state of Campeche, Mexico. Catches were carried out monthly from February 1994 to January 1995 between 18:00 and 22:00 h. Lutzomyia cruciata was the only species caught. The highest population peak of Lu. cruciata was found in March with lesser peaks in February, December 1994, and January 1995. Maximum biting rate of Lu. cruciata was found between 18:00 and 19:00 h. The host-seeking females of Lu. cruciata were directly related to levels of humidity between 88 and 100%. Low and high temperature had a negative effect upon Lu. cruciata activity. The possible role of Lu. cruciata as vector of leishmaniasis in the state of Campeche, Mexico is discussed.

Flebótomos atraídos por cebo humano fueron colectados en un foco endémico de leishmaniais cutánea localizada en el estado de Campeche, México. Colectas fueron llevadas a cabo mensualmente de Febrero 1994 a Enero 1995 entre las 18:00 a 22:00 h. Lutzomyia cruciata fue la única especie capturada. El mayor pico poblacional fue encontrado en Marzo con picos similares en Febrero, Diciembre 1994 y Enero 1995. La tasa máxima de picadura de Lu. cruciata estuvo comprendida entre 18:00 a 19:00 h. Las hembras hambientas de Lu. cruciata, fueron directamente relacionadas con niveles de humedad relativa entre 88 a 100%. Bajas y altas temperaturas tuvieron un efecto negativo sobre la actividad de Lu. cruciata. Se discute el posible papel de Lu. cruciata como vector de leishmaniasis en el estado de Campeche, México.