RESUMO
Rodents are very important organisms within ecosystems; however, some species are considered pests because they consume and damage crops and because they are vectors, hosts, or reservoirs in the transmission of emerging infectious diseases. Rodents in Bolivia are represented by 148 species, Oligoryzomys microtis (Allen, 1916) being a species of public health importance because it is considered a potential natural reservoir of the Chapare virus, which causes Chapare Hemorrhagic Fever, and it is a deadly disease for humans. Its impact on public health is still unknown. The present study consisted of recording the presence of the species O. microtis through the use of Sherman-type live capture traps for small mammals arranged in linear transects in the wild and intervened habitats of the Samuzabety community, where the Chapare virus was detected for the first time, this community is located in the Chapare Province of the department of Cochabamba, Bolivia. The species recorded were the rodents Oligoryzomys microtis (morphotype matogrossae), Proechimys brevicauda, Neacomys vargasllosai, Hylaeamys perenensis, and the marsupial Metachiurus nudicaudatus. The presence of the species O. microtis (morphotype matogrossae) in the community of Samuzabety is confirmed. This species is associated with forest habitats with nearby and surrounding crops. The species O. microtis has epidemiological relevance as it is the natural reservoir of the Río Mamoré Hantavirus and is currently considered a potential reservoir of the Chapare virus and other Arenaviruses.
Los roedores son organismos muy importantes dentro de los ecosistemas; sin embargo, algunas especies son consideradas como plagas porque consumen y dañan cultivos y porque son vectores, hospederos o reservorios en la trasmisión de enfermedades infecciosas emergentes. Los roedores en Bolivia están representados por 148 especies, entre las cuales Oligoryzomys microtis (Allen, 1916) es una especie de importancia en salud pública, debido a que es considerada como potencial reservorio natural del virus Chapare, el cual produce la fiebre hemorrágica Chapare, enfermedad mortal para el ser humano y con un impacto en la salud pública aún desconocido. En este estudio se registró la presencia de la especie O. microtis?/i>, mediante el uso de trampas de captura viva tipo Sherman para pequeños mamíferos dispuestas en transectos lineales, en los hábitats silvestres e intervenidos de la comunidad de Samuzabety, sitio en el que se detectó por primera vez el virus Chapare. Esta comunidad se encuentra ubicada en la Provincia Chapare del departamento de Cochabamba, Bolivia. Las especies registradas fueron los roedores Oligoryzomys microtis (morfotipo matogrossae), Proechimys brevicauda, Neacomys vargasllosai, Hylaeamys perenensis y el marsupial Metachiurus nudicaudatus. Se confirma la presencia de la especie O. microtis (morfotipo matogrossae) en la comunidad de Samuzabety, la cual se encuentra asociada con hábitats de bosques, con cultivos cercanos y a su alrededor. La especie O. microtis tiene relevancia epidemiológica al ser el reservorio natural del hantavirus Río Mamoré y al ser considerado actualmente como potencial reservorio del virus Chapare y de otros arenavirus.
RESUMO
Chagas disease is still a major public health problem in Bolivia mostly due to the recurrent reinfestation of houses by Triatoma infestans. The current study evaluated the danger of reinfesting bugs by determining their infection rate, the genetic group (discrete typing unit, DTU) of Trypanosoma cruzi that infect them, and the possible association of recurrent infestation with environmental variables. In the municipality of Saipina, 254 km from Santa Cruz de la Sierra, 57 dwellings with reinfestation background and the latest fumigation 1 or 2 months before were actively searched for triatomines. The infection of the bugs and the DTUs of T. cruzi were determined with PCR methods. Microenvironmental variables were estimated surfaces of the different ground covers around each dwelling. Principal component analysis (PCA) and logistic regression were applied to the data set. Among the houses visited, 54.4% were still infested with T. infestans, and 201 T. infestans were captured, 56% indoors and 43.8% outdoors. The infection rate with T. cruzi was 24%. The TcII/TcV/TcVI group of DTUs was 80%, while TcI and TcIII/TcIV had equal values of 10%. No significant differences of DTU distribution were found between nymphs and adults, females and males, nor between intradomicile and peridomicile areas. PCA identified urban and nonurban dwellings: the former was associated with intradomicile reinfestation by nymphs. From the logistic regression analyses, the intradomicile reinfestation tended to be associated with the peridomicile around dwellings. In contrast, peridomicile infestation was more associated with sylvatic areas. Interestingly, the presence of fields (pasture, crops) around the dwelling might have a protective role regarding reinfestation. The results show that vector control actions fail, and the inhabitants of the municipality of Saipina continue to be exposed to T. cruzi transmission risk.
