Are dead Triatoma infestans a competent vector of Trypanosoma cruzi?
After Triatoma infestans death, Trypanosoma cruzi survived several days, maintaining the ability to infect a vertebrate host. Dead bugs from an endemic area collected during an official spraying campaign showed mobile rectal trypanosomes up to 14 days after vector death. Two days after vector death 2,760 trypomastigotes were found alive in its rectal material. However, the number of mobile trypomastigotes decreased significantly from the 5th day after death. Laboratory proofs with third and fifth nymphal stage showed similar results. Living trypanosomes were found in their rectal material at 10 days in third stage and even at 30 days in fifth nymphal stage. The mean number of trypomastigotes had no changes up to 10 days in third nymphal stage and increased significantly from 1 to 10 days in the fifth stage. Conjunctival instillation as well as intraperitoneal inoculation to mice, of metacyclic forms from dead T. infestans produced infection in the vertebrate host. Present results show that human contact with dead vector is highly probable in summer and living and infective T. cruzi are available for transmission in the vector.
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Centro de Investigaciones Entomológicas de Córdoba, Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, República Argentina.
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D000818:Animals; D014355:Chagas Disease / Q000635:transmission*; D004199:Disease Vectors; D051379:Mice; D008807:Mice, Inbred BALB C; D013997:Time Factors; D014224:Triatoma / Q000469:parasitology*; D014349:Trypanosoma cruzi / Q000472:pathogenicity / Q000502:physiology*