Institute of Tropical Medicine, Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan.
Parasit Vectors. 2013 Jan 11;6:6. doi: 10.1186/1756-3305-6-6.
Jars, tanks, and drums provide favorable rearing/breeding sites for Aedes aegypti in Vietnam. However, the use of insecticides to control mosquitoes at such breeding sites has not been approved in Vietnam since they are also often sources of drinking water, making larval vector control difficult. Mosquito nets pre-treated with long-lasting insecticide treated nets (LLITNs) form an effective measure for malaria control. We examined changes in the abundance of immature Aedes aegypti to evaluate the efficacy of covering ceramic jars with lids comprising one type of LLITN, Olyset® Net, in inhibiting oviposition by adult females, and to evaluate the effect of treating other breeding containers, such as flower vases, inside and around the outside of houses with a slow-release pyriproxyfen formulation to kill pupae.
We selected 313 households for the trial and 363 households for the control in Tan Chanh, Long An province, Vietnam. In the trial area, Olyset® Net lids were used to cover five major types of water container (ceramic jars, cylindrical concrete tanks, other concrete tanks, plastic drums, and plastic buckets), while pyriproxyfen was used to treat flower vases and ant traps. We also monitored dengue virus transmission by measuring anti-dengue IgM and IgG levels in healthy residents in both control and trial areas to estimate the effectiveness of Olyset® Net at controlling the dengue vector, Aedes aegypti.
The container-index and house-index for immature Ae. aegypti fell steeply one month after treatment in the trial area. Lids with Olyset® Net that fit container openings clearly seemed to reduce the presence of immature Ae. aegypti as the density of pupae decreased 1 month after treatment in the trial area. Pyriproxyfen was also effective at killing pupae in the water containers in the trial area. Although the dengue seroconversion rate was not influenced by Olyset® Net, it was lower in two-five year old children when compared to older children and adults in both control and trial areas.
Our study showed that the treatment by Olyset® Net and pyriproxyfen had a strong negative effect on the prevalence of immature Ae. aegypti, which persisted for at least 5 months after treatment.
在越南，罐子、坦克和桶为埃及伊蚊提供了有利的繁殖/饲养场所。然而，由于这些容器也是饮用水的来源，在这些繁殖地使用杀虫剂来控制蚊子的做法在越南并未得到批准，这使得幼虫媒介控制变得困难。经长效杀虫剂处理的蚊帐（LLITN）预处理的蚊帐形成了控制疟疾的有效措施。我们检查了埃及伊蚊幼虫丰度的变化，以评估用一种 LLITN，Olyset® Net 覆盖陶瓷罐盖子来抑制成年雌蚊产卵的效果，并评估在房屋内外用缓释吡丙醚处理其他繁殖容器（如花瓶）以杀死蛹的效果。
我们在越南隆安省 Tan Chanh 选择了 313 户家庭进行试验，选择了 363 户家庭作为对照。在试验区，用 Olyset® Net 盖子覆盖五种主要类型的水容器（陶瓷罐、圆柱形混凝土水箱、其他混凝土水箱、塑料桶和塑料桶），同时用吡丙醚处理花瓶和蚂蚁陷阱。我们还通过测量对照区和试验区健康居民的抗登革热 IgM 和 IgG 水平来监测登革热病毒的传播，以估计 Olyset® Net 控制登革热媒介埃及伊蚊的效果。
试验区处理后一个月，埃及伊蚊的容器指数和房屋指数急剧下降。装有 Olyset® Net 盖子的容器开口明显减少了埃及伊蚊的存在，因为试验区处理后一个月蛹的密度下降。吡丙醚也能有效地杀死试验区水中的蛹。虽然 Olyset® Net 对接种登革热的血清转化率没有影响，但与对照区和试验区的年龄较大的儿童和成年人相比，2-5 岁儿童的血清转化率较低。
我们的研究表明，Olyset® Net 和吡丙醚的处理对埃及伊蚊幼虫的流行有很强的负面影响，这种影响至少持续了 5 个月。
