Chowdhury Rajib, Chowdhury Vashkar, Faria Shyla, Huda M Mamun, Laila Runa, Dhar Indrani, Maheswary Narayan P, Dash Aditya Prasad
National Institute of Preventive and Social Medicine (NIPSOM), Mohakhali, Dhaka, Bangladesh.
J Vector Borne Dis. 2014 Sep;51(3):179-87.
BACKGROUND & OBJECTIVES: In 2000, a dengue outbreak occurred in Bangladesh that included Dhaka City. Both dengue vectors, Aedes aegypti and Ae. albopictus are present in Bangladesh. Aedes aegypti mosquitoes mainly breed in and around houses and Ae. albopictus is an outside breeder. There are many old trees throughout Dhaka City in different parks, streets and the university campus which may have holes that can contribute as potential breeding habitat for the dengue vector. Therefore, a survey was conducted to investigate the presence of eggs of the dengue vector mosquitoes in treeholes during the dry season in February 2001 to know their contribution on dengue outbreaks.
All treeholes in 10 different localities (parks, streets and university campus) of Dhaka City were surveyed. All trees were examined for treeholes up to the height of approximately 3 m and sampled. Debris were collected and packed in poly bags and brought to the laboratory for detailed studies. These were then soaked with tap water to observe egg hatching. The soaked materials were kept up to 20 days covered by a fine mosquito net. After 2-3 days, the eggs started hatching and larvae were separated from the sample for rearing up to IV instar.
A total of 245 treeholes were surveyed in 49 identified tree species and 18 unidentified trees. Altogether, 1365 Aedes larvae were found, of which 1096 were Aedes albopictus and 269 were other Aedes species. The largest number of larvae was observed in Delonix regia of Leguminosae family. The number of Aedes albopictus found in the treeholes have perfect positive correlation with the number of other Aedes species. Not a single egg of Aedes aegypti was found in this survey.
INTERPRETATION & CONCLUSION: This information will inform public health workers as well as the national control programme to help to solve mosquito borne diseases specially that of dengue. This is critical in planning for vector control operations due to the diversity of dengue outbreak in the nature.
2000年，孟加拉国包括达卡市在内发生了登革热疫情。登革热的两种传播媒介埃及伊蚊和白纹伊蚊在孟加拉国都有分布。埃及伊蚊主要在房屋及其周边繁殖，而白纹伊蚊则在室外繁殖。达卡市不同公园、街道和大学校园内有许多古树，这些树可能有树洞，可作为登革热传播媒介的潜在繁殖栖息地。因此，于2001年2月旱季期间进行了一项调查，以调查树洞中登革热传播媒介蚊虫卵的存在情况，了解它们对登革热疫情的影响。
对达卡市10个不同地点（公园、街道和大学校园）的所有树洞进行了调查。检查所有树木高达约3米的树洞并进行采样。收集杂物并装入塑料袋，带回实验室进行详细研究。然后用自来水浸泡这些杂物以观察卵孵化情况。浸泡后的材料用细蚊帐覆盖保存20天。2 - 3天后，卵开始孵化，将幼虫从样本中分离出来饲养至四龄幼虫。
共调查了49种已识别树种和18种未识别树木中的245个树洞。总共发现了1365只伊蚊幼虫，其中1096只为白纹伊蚊，269只为其他伊蚊种类。在豆科的凤凰木中观察到的幼虫数量最多。树洞中发现的白纹伊蚊数量与其他伊蚊种类的数量呈完全正相关。本次调查未发现埃及伊蚊的卵。
这些信息将为公共卫生工作者以及国家防控计划提供参考，有助于解决蚊媒疾病，特别是登革热问题。鉴于登革热疫情在自然界中的多样性，这对于规划病媒控制行动至关重要。
