Triatomine vectors of Trypanosoma cruzi: a molecular perspective based on nuclear ribosomal DNA markers.
Chagas disease (American trypanosomiasis) is mainly transmitted by blood-sucking bugs of the reduviid subfamily Triatominae (Hemiptera: Prosorrhyncha). Control strategies are directed mainly against these insect vectors, as no vaccine is available and, except in the very early stage of infection, there is no effective chemótherapy. Studies of deoxyribonucleic acid (DNA) will lead to major advances in our knowledge of Triatominae and their relationships to Chagas disease transmission, epidemiology and control. Analyses of complete sequences of nuclear genes coding for ribosomal ribonucleic acid (rRNA) (rRNA genes) and spacers furnish significant information at the levels of higher taxons, genera, species, subspecies, hybrids, varieties and populations of Triatominae. This paper briefly reviews the contributions of studies on the slowly-evolving 18S or small subunit (SSU) rRNA gene and the quickly-evolving second internal transcribed spacer (ITS-2). The whole 18S rRNA gene is a useful marker for supraspecific relationships in Triatominae. ITS-2 is complementary to it, enabling resolution at specific and infraspecific levels. All the evidence suggests that ITS-2 will become the DNA marker of excellence for studies of Triatominae at specific and subspecific levels, as it is in other groups of organisms. Possible applications of data obtained from the study of rRNA and ITS-2 sequences of Triatominae are discussed.
Bargues
María Dolores
MD
Departmento de Parasitologia, Facultad de Farmacia, Universidad de Valencia, Av. Vicent Andrés Estellés s/n, 46100 Burjassot-Valencia, Spain. m.d.bargues@uv.es
Marcilla
Antonio
A
Dujardin
Jean Pierre
JP
Mas-Coma
Santiago
S
D000818:Animals; D014355:Chagas Disease / Q000453:epidemiology / Q000635:transmission*; D005819:Genetic Markers; D006801:Humans; D007303:Insect Vectors / Q000145:classification / Q000235:genetics / Q000469:parasitology*; D010802:Phylogeny; D012335:RNA, Ribosomal / Q000235:genetics*; D014225:Triatominae / Q000145:classification / Q000235:genetics / Q000469:parasitology*; D014349:Trypanosoma cruzi / Q000235:genetics
D005819:Genetic Markers; D012335:RNA, Ribosomal