ABSTRACT
The Chagas disease is caused by the parasite Trypanosoma cruzi, which infect blood-feeding triatomine bugs to finally reach mammal hosts. Chagas disease is endemic in Latin America, and is ranked among the 13 neglected tropical diseases worldwide. Currently, an estimate of 7 million people is infected by T. cruzi, leading to about 22 000 deaths per year throughout the Americas. As occurs with other vectors, a major question towards control programs is what makes a susceptible bug. In this review, we focus on findings linked to insect gut structure and microbiota, immunity, genetics, blood sources, abiotic factors (with special reference to ambient temperature and altitude) to understand the interactions occurring between T. cruzi and triatomine bugs, under a co-evolutionary scenario. These factors lead to varying fitness benefits and costs for bugs, explaining why infection in the insect takes place and how it varies in time and space. Our analysis highlights that major factors are gut components and microbiota, blood sources and temperature. Although their close interaction has never been clarified, knowledge reviewed here may help to boost the success of triatomine control programs, reducing the use of insecticides.
Subject(s)
Chagas Disease/transmission , Insect Vectors/drug effects , Triatoma/drug effects , Trypanosoma cruzi/genetics , Animals , Biological Evolution , Disease Transmission, Infectious , Gastrointestinal Microbiome , Genome, Insect , Humans , Insect Vectors/genetics , Insect Vectors/microbiology , Insect Vectors/parasitology , Insecticides/pharmacology , Triatoma/parasitology , Trypanosoma cruzi/drug effectsABSTRACT
In order to determine the risk of transmission of Trypanosoma cruzi by triatomines in Metztitlan municipality, Hidalgo State, Mexico, entomological indexes were calculated and the characteristics of dwellings were described. A transversal, retrospective, descriptive, and observational study was performed by means of an intentional not probabilistic and expertise sampling from January to December of 2005 in 10 localities in which presence of triatomines were investigated either intra or peridomestic environmental in 699 houses. Building material and presence of infected triatomines with T. cruzi were registered to determine entomologic indexes. The triatomine species collected were: Triatoma barberi (Usinger) and T. mexicana (Herrich-Schaeffer) (Hemiptera: Reduviidae). The results indicated that natural infection index varied from 7.7 percent to 50 percent; colonization index reached 80 percent; infestation index varied from 7.7 percent to 25 percent; dispersion index was 70 percent. Stone-walled houses were more infested. We can conclude that it is necessary to establish T. cruzi transmission control measures against triatomines in localities from Metztitlan, primarily in stone-walled houses where T. barberi occurs, as it was the most important vector species in the transmission of T. cruzi in this municipality.
Subject(s)
Humans , Chagas Disease/transmission , Demography , Housing , Mexico , Risk FactorsABSTRACT
Se informa que en dos localidades, una perteneciente al estado de Queretaro y otra al de Guanajuato, se encontro Triatoma barberi. Se hace enfasis en el hallazgo debido a que estos dos estados aun no se habian senalado en la literatura medica con triatominos transmisores de enfermedad de Chagas. De esta manera se cubre todo el territorio nacional, en el cual existen una o mas poblaciones pertenecientes a cada uno de los estados con informes de hallazgos de triatominos infectados y no infectados en forma natural con Trypanosoma cruzi
