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.
Highlights
Triatoma rubrofasciata is the only kissing bug species distributed globally
T. rubrofasciata from Asia is not infected with Tryp. cruzi, it is frequently feeding on humans, causing severe bite reactions that sometimes lead to anaphylactic shock [3, 7,8,9,10,11,12]
To the best of our knowledge, this study reports for the first time a natural infection of triatomine insects with Tryp. lewisi (27%), a pathogenic parasite for humans which could represent an important burden on human health [21]
Summary
Triatoma rubrofasciata is the only kissing bug species distributed globally. In the Americas, this species transmits the parasite Trypanosoma cruzi, responsible for Chagas disease. There are around 150 triatomine species worldwide, most of them vectors of Trypanosoma cruzi, causative agent of Chagas disease in the Americas [1] Of these species, only T. rubrofasciata is found in both New and Old Worlds [2], having been reported in many localities in Asia, Africa, the Americas (South, Central and North America), islands of the Indian Ocean, Pacific Ocean and the Azores in the Atlantic Ocean [1, 3]. Only T. rubrofasciata is found in both New and Old Worlds [2], having been reported in many localities in Asia, Africa, the Americas (South, Central and North America), islands of the Indian Ocean, Pacific Ocean and the Azores in the Atlantic Ocean [1, 3] In this century the occurrence of this species in the Americas has been restricted to coastal cities from Brazil. T. rubrofasciata from Asia is not infected with Tryp. cruzi, it is frequently feeding on humans, causing severe bite reactions that sometimes lead to anaphylactic shock [3, 7,8,9,10,11,12]
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