Developing new approaches for detecting and preventing Aedes aegypti population outbreaks: basis for surveillance, alert and control system.
A new approach to dengue vector surveillance based on permanent egg-collection using a modified ovitrap and Bacillus thuringiensis israelensis(Bti) was evaluated in different urban landscapes in Recife, Northeast Brazil. From April 2004 to April 2005, 13 egg-collection cycles of four weeks were carried out. Geo-referenced ovitraps containing grass infusion, Bti and three paddles were placed at fixed sampling stations distributed over five selected sites. Continuous egg-collections yielded more than four million eggs laid into 464 sentinel-ovitraps over one year. The overall positive ovitrap index was 98.5% (over 5,616 trap observations). The egg density index ranged from 100 to 2,500 eggs per trap-cycle, indicating a wide spread and high density of Aedes aegypti (Diptera: Culicidae) breeding populations in all sites. Fluctuations in population density over time were observed, particularly a marked increase from January on, or later, according to site. Massive egg-collection carried out at one of the sites prevented such a population outbreak. At intra-site level, egg counts made it possible to identify spots where the vector population is consistently concentrated over the time, pinpointing areas that should be considered high priority for control activities. The results indicate that these could be promising strategies for detecting and preventing Ae. aegypti population outbreaks.
Regis
Lêda
L
Instituto Nacional de Pesquisas Espaciais, São José dos Campos, SP, Brasil. leda@cpqam.fiocruz.br
Monteiro
Antonio Miguel
AM
Melo-Santos
Maria Alice Varjal de
MA
Silveira
José Constantino
JC
Furtado
André Freire
AF
Acioli
Ridelane Veiga
RV
Santos
Gleice Maria
GM
Nakazawa
Mitsue
M
Carvalho
Marilia Sá
MS
Ribeiro
Paulo Justiniano
PJ
Souza
Wayner Vieira de
WV
D000330:Aedes; D000818:Animals; D003715:Dengue / Q000517:prevention & control / Q000635:transmission; D007303:Insect Vectors; D009032:Mosquito Control / Q000379:methods*; D010063:Ovum; D011156:Population Density; D011159:Population Surveillance; D012621:Seasons