Biological attributes of the kissing bug Triatoma rubrofasciata from Vietnam

Abstract

BackgroundTriatoma rubrofasciata is the only kissing bug species distributed globally. In the Americas, this species transmits the parasite Trypanosoma cruzi, responsible for Chagas disease. The presence of T. rubrofasciata in several Asian countries has greatly increased recently. In Vietnam, it is found in large numbers, closely associated with human environments. Although T. rubrofasciata from Asia is not infected with Tryp. cruzi, it carries other parasites such as Trypanosoma lewisi and Trypanosoma conorhini. Reports of bites by T. rubrofasciata have increased significantly in several places of Vietnam, becoming a public health problem as it produces severe anaphylactic reactions.MethodsSpecimens of T. rubrofasciata were collected from seven provinces in central Vietnam. We analyzed different biological attributes (life-cycle, starvation resistance, feeding and reproductive capacities) and genetic characteristics (chromosomes and DNA sequences) of T. rubrofasciata from Vietnam and compared them with Brazilian specimens. Natural infection with Tryp. conorhini and Tryp. lewisi were analyzed in a sample of 100 collected insects.ResultsSpecies identification of T. rubrofasciata from central Vietnam was corroborated by genetic markers. Cytogenetic analyses showed that T. rubrofasciata from central Vietnam share the same chromosomal characteristics with individuals from Brazil and Hanoi. DNA sequence analyses of a mitochondrial cytochrome b gene fragment showed little variation between Old and New World specimens. Our study sample, compared with Brazilian individuals, showed a higher survival capacity revealed by a higher hatching rate (98% compared with 80.5%), a larger amount of blood taken in single meal and long-term starvation resistance. Furthermore, this species had a high natural rate of infection with Tryp. conorhini (46%) and Tryp. lewisi (27%).ConclusionsFor T. rubrofasciata of Vietnam, a high rate of fecundity throughout the year, a high capacity for starvation, and its occurrence in synanthropic environments of urban areas with a high availability of food sources are risk factors to be taken into account by vector control campaigns. The several allergic reactions caused by their bites and their high infection with Tryp. lewisi highlight the need to implement specific control programmes for T. rubrofasciata in Vietnam.

Distribution of Triatomines, the Vector of Chagas Disease — Southern China, 2016−2018

“…For example, in Guangxi, T. rubrofasciata was captured in 13 out of 14 prefecture-level cities; Guilin City was the only exception (7). For this report, this insect presented dispersion favored by interactions with residential settlements and human activities (8). In this study, all samples were collected by local residents around their settlements, and field environments were also investigated by light traps and Noireau traps but no samples were collected.…”

The spreading of parasites by human migratory activities

“…The tropicopolitan distribution range of the triatomine species T. rubrofasciata (Table 4), a vector for T. cruzi in Latin America, can be only explained by recent spreading events. DNA sequence analyses using nuclear and mitochondrial marker genes showed high similarity between New World and Old World specimens indicating a common and recent origin of Asian and American populations of T. rubrofasciata [110,111]. The close association of T. rubrofasciata with domestic rats (especially R. rattus) suggests that the triatomine bug was spread around the globe by international shipping during the sixteenth to eighteenth centuries [112].…”

“…An alternative hypothesis proposes that the triatomine bug is of Asian origin and was recently introduced into the Americas [42]. Meanwhile, T. rubrofasciata has become a serious biting nuisance and a public health problem in Vietnam as bites by the insect can produce severe anaphylactic reactions in humans [42,111]. Reports of people bitten by the triatomine bug have significantly increased in different Vietnamese cities over the last decade [111].…”

“…Meanwhile, T. rubrofasciata has become a serious biting nuisance and a public health problem in Vietnam as bites by the insect can produce severe anaphylactic reactions in humans [42,111]. Reports of people bitten by the triatomine bug have significantly increased in different Vietnamese cities over the last decade [111]. The reason for the current widespread infestation of T. rubrofasciata in urban areas in Vietnam is unclear.…”

Do the new triatomine species pose new challenges or strategies for monitoring Chagas disease? An overview from 1979-2021

“…Reports of this species in Asia have increased significantly in the last five years. 41 , 42 Recently, this species has also been recorded in China. 43 , 44 Thus, its epidemiological importance is a matter of concern.…”