Sympatry influence in the interaction of Trypanosoma cruzi with triatomine

Abstract

Introduction: Trypanosoma cruzi, the etiologic agent of Chagas disease, is widely distributed in nature, circulating between triatomine bugs and sylvatic mammals, and has large genetic diversity. Both the vector species and the genetic lineages of T. cruzi present a varied geographical distribution. This study aimed to verify the influence of sympatry in the interaction of T. cruzi with triatomines. Methods: The behavior of the strains PR2256 (T. cruzi II) and AM14 (T. cruzi IV) was studied in Triatoma sordida (TS) and Rhodnius robustus (RR). Eleven fifth-stage nymphs were fed by artificial xenodiagnosis with 5.6 × 10 3 blood trypomastigotes/0.1mL of each T. cruzi strain. Every 20 days, their excreta were examined for up to 100 days, and every 30 days, the intestinal content was examined for up to 120 days, by parasitological (fresh examination and differential count with Giemsa-stained smears) and molecular (PCR) methods. Rates of infectivity, metacyclogenesis and mortality, and mean number of parasites per insect and of excreted parasites were determined. Results: Sympatric groups RR+AM14 and TS+PR2256 showed higher values of the four parameters, except for mortality rate, which was higher (27.3%) in the TS+AM14 group. General infectivity was 72.7%, which was mainly proven by PCR, showing the following decreasing order: RR+AM14 (100%), TS+PR2256 (81.8%), RR+PR2256 (72.7%) and TS+AM14 (36.4%). Conclusions: Our working hypothesis was confirmed once higher infectivity and vector capacity (flagellate production and elimination of infective metacyclic forms) were recorded in the groups that contained sympatric T. cruzi lineages and triatomine species.

Synanthropic triatomines (Hemiptera: Reduviidae): infestation, colonization, and natural infection by trypanosomatids in the State of Rio Grande do Norte, Brazil

“…Moreover, it is difficult to examine the developmental stage of triatomines using this method as the insects are not alive 41 , and staining quality may affect the specificity of the assay, thus hindering the morphological distinction between T. cruzi and other trypanosomatides, such as Trypanosoma rangeli 42 . Recent data have shown that a combination of methods (e.g., direct examination, xenoculture, and polymerase chain reaction) is best for detection of T. cruzi 10,43 .…”

Vector competence and feeding-excretion behavior of Triatoma rubrovaria (Blanchard, 1843) (Hemiptera: Reduviidae) infected with Trypanosoma cruzi TcVI

“…Metacyclogenesis is an T. cruzi adaptive differentiation due to nutritional and oxidative stress in the triatomine gut [53]. Therefore, it is unsurprising that vectors and parasites circulating at a same biotope may have a better interaction due to coevolution [54], including higher metacyclogenesis rates [55]. For triatomines and T. cruzi, this coevolution would result in successful infections and transmission cycles (i.e.…”

Infection susceptibility and vector competence of Rhodnius robustus Larrousse, 1927 and R. pictipes Stal, 1872 (Hemiptera, Reduviidae, Triatominae) for strains of Trypanosoma cruzi (Chagas, 1909) (Kinetoplastida, Trypanosomatidae) I, II and IV

“…In studies on the interaction of different strains of T. cruzi with the main vector species, variations in both protozoan population density and insect infection rates have been reported [ 2 , 24 – 26 ]. The mean positivity rates among different triatomine species ranged from 9.8% in Triatoma dimidiata Latreille, 1811 to 91.4% in Triatoma pseudomaculata Corrêa & Espínola, 1964, with an overall mean positivity rate of 67.3% [ 2 ].…”

“…Although the complex interaction between T. cruzi and its vector for transmissibility is not yet fully understood, it is known that this interaction can be influenced by the biological, biochemical and genetic characteristics of both the vector and the parasite, combined with the fact there are sympatric species that are better adapted to the environment in which they are inserted [ 26 – 29 ]. In addition, the hematophagous habits of the vectors contribute to the selection of populations of T. cruzi , in that some genetic lineages can be eliminated while in others an increase in the population can occur, even when they are concomitant in the vector [ 30 ].…”