Effects of flooding of the River Paraná on the temporal activity of Anopheles (Nyssorhynchus) darlingi Root (Diptera: Culicidae), at the border state of Mato Grosso do Sul and São Paulo, Brazil

Abstract

INTRODUCTION: Study of the temporal activity of malaria vectors during the implantation of a hydroelectric power station on the River Paraná, intended to generate electrical energy. The river separates the States of São Paulo and Mato Grosso do Sul, in Brazil. The objective was to verify whether alterations occurred in the wealth and diversity indices of Anopheles, following two successive floods, extended to the temporal activity and nycthemeral rhythm followed over a five year period. METHODS: Mosquito capture was performed monthly using the Human Attraction Technique and Shannon Traps. The first, executed for 24h, provided the nycthemeral rhythm and the second, lasting 15h, permitted the tracking of Anopheles during the two floods. RESULTS: The bimodal pattern of Anopheles darlingi defined before these floods was modified throughout the environment interventions. The same effect had repercussions on the populations of An albitarsis s.l., An triannulatus and An galvaoi. Activity prior to twilight was less affected by the environment alterations. CONCLUSIONS: The dam construction provoked changes in Anopheles temporal activity patterns, permitting classification of the area as an ecologically steady and unstable situation. Differences observed in Anopheles behavior due to the capture methods revealed the influence of solo and multiple attractiveness inside the populations studied.

Malaria in Brazil: what happens outside the Amazonian endemic region

“…The numerous water reservoirs from recently constructed hydroelectric plants increased the number of suitable larval habitats for An. darlingi as well as for other potential Nyssorhynchus malaria vectors, such as species of the Albitarsis and Triannulatus complexes ( Gomes et al 2008 , 2013 , Limongi et al 2008 , Meneguzzi et al 2009 , Da Silva et al 2013 , McKeon et al 2013 , Ribeiro et al 2013 ). Along the coastal lowlands, introduced malaria cases and/or small epidemics have emerged on occasion and localities with brackish water and Nyssorhynchus and An.…”

Effects of Artificial Flooding for Hydroelectric Development on the Population ofMansonia humeralis(Diptera: Culicidae) in the Paraná River, São Paulo, Brazil

“…Although the reservoir impacts several municipalities in Mato Grosso do Sul [8, 9] and São Paulo states [10], the study area was located in the Presidente Epitácio Municipality in São Paulo state, part of a larger project developed in this area.…”

Brazilian mosquito (Diptera: Culicidae) fauna: I. Anopheles species from Porto Velho, Rondônia state, western Amazon, Brazil

“…The specimen was therefore labeled in Table 2 During operation period, apparently, power transmission line does not represent a major environmental impact in Rondônia State because they do not interfere directly with water resources or flooding. By the construction period, moreover, the potential risk for new malaria transmission cycles in the region is low because workers are primarily active during daylight, whereas vectors generally blood feed at night in the peri/intradomicile 3,15 . Nevertheless, it is important that construction companies should maintain malaria prevention and vector control programs, because the main vector was detected along the line.…”