Can body traits, other than wings, reflect the flight ability of Triatominae bugs?

Introduction: Insects of the subfamily Triatominae are vectors of Trypanosoma cruzi , the Chagas disease parasite, and their flying behavior has epidemiological importance. The flying capacity is strikingly different across and within Triatominae species, as well as between sexes or individuals. Many Triatoma infestans individuals have wings but no flying muscles.

Control of rural house infestation by Triatoma infestans in the Bolivian Chaco using a microencapsulated insecticide formulation.

Background: Triatoma infestans, the main vector of Trypanosoma cruzi (causative agent of Chagas disease) has been successfully eliminated over much of its original geographic distribution over the southern cone countries of South America. However, populations of the species are still infesting houses of rural communities of the Gran Chaco region of Argentina and Bolivia. This study reports for the first time a large-scale effect of a vector control intervention using a microencapsulated formulation of organophosphates and insect growth regulator on house infestation by T.

Circadian entrainment by light and host in the Chagas disease vector, Triatoma infestans.

Triatoma infestans (Reduviidae: Triatominae, "kissing bug") is the main insect vector of Trypanosoma cruzi, the causative agent of Chagas disease, a chronic trypanosomiasis infecting 10 million people world-wide. This hematophagous bug feeds on diurnal and nocturnal species during each host's quiescent time. As the hosts are also its major predators, kissing bugs are subjected to dual selective pressures from a single source.

New structures for goat corrals to control peridomestic populations of Triatoma infestans (Hemiptera: Reduviidae) in the Gran Chaco of Argentina.

Goat production is an important economic activity for rural communities in the Gran Chaco of Argentina. Goat corrals are important for the survival of peridomestic populations of Triatoma infestans. This study evaluated the impact of modifying the traditional structure of goat corrals on T.

Potential sources of Triatoma infestans reinfesting peridomiciles identified by morphological characterization in Los Llanos, La Rioja, Argentina.

The presence of Triatoma infestans in habitats treated with insecticides constitutes a frequent problem in endemic areas. Basing our study on the hypothesis that descendants of a residual population should be more similar to the pre-treatment population than to any other, we compared the indications of two quantitative morphological approaches. This study seeks to find the origin of 247 T.

The residual efficacy of a cypermethrin pour-on formulation applied on goats on the mortality and blood intake of Triatoma infestans.

Triatoma infestans is the main vector of Trypanosoma cruzi, the aetiological agent of Chagas disease in the Gran Chaco region of South America. As a frequent blood meal source for triatomine bugs, domestic goats play a key role in the eco-epidemiology of Chagas disease. The aim of this study was to evaluate the mortality and blood intake of T.

Effects of fipronil on dogs over Triatoma infestans, the main vector of Trypanosoma cruzi, causative agent of Chagas disease.

Chagas disease is the most important endemic disease in Latin America, mainly transmitted by Triatoma infestans in the Southern Cone countries of South America. Dogs are one of the main domestic reservoirs of Trypanosoma cruzi, the etiological agent of Chagas disease. The presence of dogs in rural households of endemic areas significantly increases the likelihood of the vectorial transmission of the parasite.

Exploring the association between Trypanosoma cruzi infection in rural communities and environmental changes in the southern Gran Chaco.

The association between land use and land cover changes between 1979-2004 in a 2.26-million-hectare area south of the Gran Chaco region and Trypanosoma cruzi infection in rural communities was analysed. The extent of cultural land, open and closed forests and shrubland up to 3,000 m around rural communities in the north, northwest and west of the province of Córdoba was estimated using Landsat satellite imagery.

Variability of the susceptibility to deltamethrin in Triatoma infestans: the female factor.

We analyzed the variability of susceptibility to deltamethrin in putatively susceptible Triatoma infestans Klug (Hemiptera: Reduviidae), and evaluated the sample size implications on the hypotheses used in the current World Health Organization protocol for the measure of insecticide resistance in Triatominae. Following the protocol, using topical application of deltamethrin to unfed first instar nymphs of T. infestans, we found that susceptibility showed significant differences between offspring from different females, a significant association with female age, and significant interaction female x female age.

The infra-red (IR) landscape of Triatoma infestans. An hypothesis about the role of IR radiation as a cue for Triatominae dispersal.

This paper presents the infrared (IR) emission spectrum of hosts and habitats of Triatoma infestans in the chaco region of NW Argentina, representing the first attempt to correlate the natural infrared stimulus with the known behaviour of these blood-sucking insect, vectors of Trypanosoma cruzi--causative agent of Chagas disease. The study was carried out in two rural villages of La Rioja Province (Argentina). A FLYR i40 camera was used to obtain IR pictures which were analyzed to determine the thermal range for humans, domestic animals, building materials, and general background emissions.

Dispersal of Triatoma infestans and other Triatominae species in the arid Chaco of Argentina: flying, walking or passive carriage? The importance of walking females.

The aim of this paper was to analyse the active dispersal of Triatoma infestans and the role of chickens as passive carriers of this insect in peridomestic areas of La Rioja, Argentina. To measure active dispersal, monthly catches were made on six consecutive nights for five months (in the warm season) using light traps (for flying insects) and sticky dispersal barriers (for walking insects). The nutritional and reproductive states of adults were evaluated.

The effects of cypermethrin pour-on and piperonyl butoxide on Triatoma infestans under laboratory conditions.

The effect of exposing Triatoma infestans to chickens treated with cypermethrin pour-on combined with piperonyl butoxide (PBO) was studied. Four groups of treated chickens and one control group were used. Each treatment received 1 or 2 ml of the cypermethrin formulation with and without PBO.

Phenotypic variability of Rhodnius ecuadoriensis populations at the Ecuadorian central and southern Andean region.

Rhodnius ecuadoriensis is an important vector of Chagas disease in Ecuador. Whereas only sylvatic and peridomestic populations are common in Manabi province, this species occupies domestic, peridomestic, and sylvatic habitats in Loja province where high reinfestation of houses was observed. To explore the existence of phenetic changes linked to the domiciliation of the species, this study set out to analyze the wing and antennal phenotypes of R.

Phenotypic variability and population structure of peridomestic Triatoma infestans in rural areas of the arid Chaco (Western Argentina): spatial influence of macro- and microhabitats.

Triatoma infestans, one of the main vectors of Trypanosoma cruzi, is strongly associated with rural human ecotopes. Infested peridomestic places could act as a source of house infestation as a result of the movement of vectors among habitats. The quantitative study of phenotypic traits and nutritional variables could be informative about the population structure and the relative mobility of vectors.

Seroprevalence of Trypanosoma cruzi infection and vector control activities in rural communities of the southern Gran Chaco (Argentina).

We compared age-related seroprevalence of Trypanosoma cruzi infection with history of vector control interventions and social and ecological changes in three historically endemic departments of Cordoba province, Argentina, covering an area of 42,600 km(2) of the Gran Chaco region. Using a cross sectional design, blood samples of 5240 people between 6 months and 40 years of age, living in 192 rural communities were analyzed to detect T. cruzi infection using ELISA tests, and confirmed with indirect immunofluorescent antibody test and indirect haemoagglutination.

Experimental evaluation of insecticidal paints against Triatoma infestans (Hemiptera: Reduviidae), under natural climatic conditions.

Background: Triatoma infestans is the main vector of Chagas disease in the Gran Chaco region of South America. The traditional spraying technique used for the application of pyrethroid insecticides has shown low efficiency in the elimination of the vector species populations occupying peridomestic structures of rural houses in the endemic area of Argentina. As part of studies looking for better alternatives, we evaluated the residual effect of insecticidal paints on the mortality of fourth instar nymphs of T.

Response of Triatoma infestans to pour-on cypermethrin applied to chickens under laboratory conditions.

This article reports the effects of a pour-on formulation of cypermethrin (6% active ingredient) applied to chickens exposed to Triatoma infestans, the main vector of Chagas disease in rural houses of the Gran Chaco Region of South America. This study was designed as a completely random experiment with three experimental groups and five replicates. Third instar nymphs were fed on chickens treated with 0, 1 and 2 cc of the formulation.

Spatial stratification of house infestation by Triatoma infestans in La Rioja, Argentina.

Vectorial transmission of Chagas disease has been decreasing over the past few decades because of effective vector control programs in the southern cone of South America. However, the disease is still actively transmitted within the Gran Chaco region. In this area, vector populations are abundant and highly prevalent in poor rural houses.

Inferences about antennal phenotype: the "Triatoma maculata complex" (Hemiptera: Triatominae) is valid?

The "Triatoma maculata complex" is presently formed by two epidemiologically important species of Triatominae, Triatoma maculata and Triatoma pseudomaculata, which share morphologic and chromatic characteristics. In order to clarify the systematic status and infer the evolutionary relationships of these vectors of Chagas disease, we performed a comparative analysis of their antennal phenotype, taking also into account Triatoma wygodzinskyi, a possible sister species. The comparison was based on sensilla arrays on the three distal segments of the antenna.

The sex ratio distortion in the human head louse is conserved over time.

Background: At the turn of the 19th century the first observations of a female-biased sex ratio in broods and populations of the head louse, Pediculus humanus capitis, had been reported. A study by Buxton in 1940 on the sex ratio of lice on prisoners in Ceylon is still today the subject of reanalyses. This sex ratio distortion had been detected in ten different countries.

Entomological aspects of Chagas' disease transmission in the domestic habitat, Argentina.

Objective: To study the risk of Trypanosoma cruzi domestic transmission using an entomological index and to explore its relationship with household's characteristics and cultural aspects.

Methods: There were studied 158 households in an endemic area in Argentina. Each household was classified according to an entomological risk indicator (number of risky bites/human).