ABSTRACT
Characteristics of Trypanosoma cruzi infection were studied in a rural area of the eastern plains of Colombia. Using enzyme-linked immunosorbent assay and indirect fluorescent-antibody tests, the infection was determined in 11.6% of the inhabitants of 142 dwellings. During 6 months of community surveillance, in 42.3% dwellings, 609 triatomines were collected (597 Rhodnius prolixus and seven, three, one, and one of Panstrongylus geniculatus, Psammolestes arturi, Eratyrus mucronatus, and Triatoma maculata, respectively). Rhodnius prolixus was found in 80% peridomiciliary Attalea butyracea palms examined with baited traps, and its infection with T. cruzi was 30% and 38.5% in dwellings and palms, respectively. Trypanosoma cruzi was isolated in five of 35 triatomines and in one of 24 dogs. The blood of domestic and wild animals was identified in triatomines collected in the intradomicile and in palms. These results support the extension of the wild cycle of T. cruzi to human dwellings and the characterization of a new scenario for transmission in Colombia.
Subject(s)
Chagas Disease/epidemiology , Chagas Disease/transmission , Insect Vectors/physiology , Triatominae/physiology , Trypanosoma cruzi , Adolescent , Adult , Aged , Animals , Child , Colombia/epidemiology , Feeding Behavior , Female , Housing , Humans , Male , Middle Aged , Young AdultABSTRACT
Eratyrus mucronatus, es un vector secundario de la enfermedad de Chagas con reportes de domiciliación en Colombia y Venezuela; los pocos estudios realizados muestran que en condiciones de laboratorio tiene bajos porcentajes de eclosión y altas tasas de mortalidad en su ciclo de vida. El fin de este trabajo fue establecer estadísticos vitales de esta especie para su cría en laboratorio. Se utilizó una cepa de laboratorio de E. mucronatus y se realizaron bioensayos para: estimar tiempos de desarrollo ninfal, comparar la eclosión en diferentes condiciones ambientales y comparar la fecundidad usando dos fuentes de alimentación y varios tipos de soporte. El tiempo promedio de desarrollo desde huevo hasta adulto fue de 127,6 días, con una tasa de supervivencia de 67,4% y probabilidades de morir en los estadios huevo de 0,2 y ninfa I de 0,16. Sesenta hembras semanalmente ovipusieron 744,5±120,77, con tasas de oviposición diaria por hembra de 1,19-2,69. Las tasas de eclosión más altas (80%) se obtuvieron en condiciones de temperatura de 24-25°C y humedad relativa de 65%. La fecundidad usando dos fuentes de alimentación y varios tipos de soporte, no mostró diferencias estadísticamente significativas. Se aportan datos para conocer estadísticos vitales como la duración del ciclo de vida, fecundidad y fertilidad de E. mucronatus, una especie de creciente importancia epidemiológica.
Eratyrus mucronatus is a secondary vector of Chagas disease with domicilary reports in Colombia and Venezuela. There are few studies in this specie and show under laboratory conditions low hatching rates and high mortality rates. The purpose of this study was to establish conditions that will improve the fertility of this species for laboratory rearing. A laboratory colony of E. mucronatus was used and bioassays were conducted to: estimate nymphal development times, compare hatching in different environmental conditions and compare fertility using two food sources and various types of support. The average development time from egg to adult was 127.6 days, with a survival rate of 67.4 %; egg mortality was 20% and that of nymph I 16%. 60 females produced 744.5 ± 120.77 eggs weekly, and the daily oviposition rate per female was 1.19 to 2.69. The best hatching rates (80 %) were obtained in stable conditions of temperature and relative humidity (65%). The fecundity differences using two food sources and various types of support, showed no statistical significance. The present study reports data useful for knowing vital statistics such as the cycle of life, fecundity, fertility and population dynamics of Triatominae species, especially those anthropophilic or suspected of invading the home environment, it is important to assess their potential for colonization capacity as well as in studies where the use of a large number of nymphs is required.
ABSTRACT
Chagas disease is a severe public health problem in Latin-American countries. In Colombia, the predominance of Trypanosoma cruzi I has been described in the literature, with a broad heterogeneity between strains. However, most of the studies carried out centered on isoenzyme analysis, with a smaller number that focus on other molecular methods. In this report, we discuss the results of a molecular analysis of T. cruzi I strains, isolated from the domestic cycle, from the department of Santander, one of the territorial divisions where the prevalence of infection is highest. Internal transcribed spacer-restriction fragment length polymorphism and random amplification of polymorphic DNA were used to characterize 16 strains from human and vector (Triatominae) hosts. The data reveal a clustering based on the biological origin. Human and vector strains grouped separately; however, three vector strains clustered together with human strains. These results indicate that genetic differences exist in the strains that infect both hosts. We conclude that T. cruzi I populations in the domestic cycle of transmission of Chagas disease in Santander are heterogeneous and are composed of different clones. The epidemiological and biological implications are discussed.
