Susceptibilidade e sobrevivência de rhodinus robustus e triatoma maculata à infecção pelo trypanosoma cruzi após xenodiagnóstico de pacientes com doença de Chagas

Abstract

Triatomines are hematophagous, hemimetabolous insects that live in colonies. predominantly in wild environments. The availability of their food source favors their life cycle, a habit that places them in the biological cycle of Trypanosoma cruzi, the agent of Chagas disease. They are important vectors for public health because present species considered vectors in the transmission of the etiological agent. Objective: To describe the fitness of Rh. robustus and T. maculata used in the xenodiagnosis (XD) of patients with CD. patients with CD and to investigate their susceptibility to T. cruzi infection. Materials Methods: 360 third-stage nymphs were observed for 90 days after being used in the period of 30 minutes in the xenodiagnosis of 18 patients with suspected acute Chagas disease (ACD). Disease (ACD). Two groups of triatomines containing 180 stage III nymphs of Rh. robustus and 180 T. maculata were separated. In group G1, 108 nymphs were used to evaluate the fitness between the species used in the XD. The variables observed were amount of blood ingested; defecation lapse; time between moulting, and mortality rate. In group G2 108 nymphs were submitted for evaluation of susceptibility to T. cruzi, estimating the rate of infection through abdominal compression by abdominal compression and visualization of flagellated forms under an optical microscope. The nymphs were weighed before and after feeding, and the development time was calculated using the Student's were calculated using Student's t-test and positivity for T. cruzi using Fisher's exact test. cruzi with Fisher's exact test, which shows a significant value with p < 0.05 and a 95% confidence interval. 95% confidence interval. Results: There was a difference between the averages of blood ingested by the two species. two species. Rh. robustus (0.116  0.095) and T. maculata (0.101  0.052) (p > 0.563). defection of Rh. robustus occurred simultaneously after feeding, while in T. maculata, it was after 10-15 days after feeding. maculata, it was after 10-15 minutes, with a difference in the amount of feces and urine between the two species. species. The time between stage change was similar in both groups, Rh. robustus showed a stage change of 12-14 days and T. maculata 16-21 days. The mortality rate in G1 ranged from 33.3% at 7 days to 100% at 90 days of observation for both species. In G2, T. cruzi infection was detected in both species at 7 days after feeding. In T. maculata - 7d(50%), 30d(33.3%), 60d(23.5%) and 90d(16.7%) while in R. robustus at 7d(33.3%), 30d(17.6%), 60d(5.6%) and 90d(27.8%). T. maculata was more susceptible 29/126 (23.01%) compared to Rh. robustus 23/126 (18.25%). Conclusion: Rh. robustus ingested greater amount of blood, with immediate defecation, with a faster stage change interval both species showed susceptibility to T. cruzi with a small difference in infection rate. difference in infection rate. T. maculata showed later emergence and a slower defecation lapse, however defecation, however, it can be used for xenodiagnosis due to its higher susceptibility rate. be used in xenodiagnosis. Keywords: Triatomines, hematophagy, T. cruzi infection.