National Institute of Hygiene and Epidemiology, 1 Yersin Street, Hanoi, 10000, Vietnam.
IRIM, University of Montpellier, CNRS, Montpellier, France.
Parasit Vectors. 2017 Nov 9;10(1):556. doi: 10.1186/s13071-017-2422-z.
Dengue virus remains a major threat in Vietnam, while chikungunya virus is expected to become one. Surveillance was conducted from 2012 to 2014 in Vietnam to assess the presence of dengue and chikungunya viruses in patients hospitalized with acute fever in five Vietnam provinces neighboring Lao PDR and Cambodia. Surveillance was extended to mosquitoes present in the vicinity of the patients' households.
A total 558 human serum samples were collected along with 1104 adult mosquitoes and 12,041 larvae from 2250 households. Dengue virus was found in 17 (3%) human serum samples and in 9 (0.8%) adult mosquitoes. Chikungunya virus was detected in 2 adult mosquitoes (0.18%) while no chikungunya virus was detected in humans. Differing densities of mosquito populations were found, with the highest in the Long An Province border with Cambodia. Long An Province also displayed the lowest rate of infection, despite a very high Breteau Index, high human population density and presence of the main cross border road system. The highest incidence was found in Dac Nong Province, where the Breteau and Container indices were the second lowest. Dengue virus was detected in five Aedes albopictus, three Aedes aegypti and one Culex vishnui. Chikungunya virus was detected in two Ae. aegypti. All infected mosquitoes belonged to haplotypes described in other parts of the world and a number of novel haplotypes were found among uninfected mosquitoes.
Dengue is considered to be regularly introduced to Vietnam from Cambodia, mostly through human movement. The data reported here provides a complementary picture. Due to intensive international trade, long-distance transportation of mosquito populations may play a role in the regular importation of dengue in Vietnam through Ho Chi Minh City. It is important to decipher the movement of mosquitoes in Vietnam, not only at the Lao PDR and Cambodia borders but also through international trade routes. Mosquito surveillance programs should address and follow mosquito populations instead of mosquito species.
登革热病毒仍然是越南的主要威胁，而基孔肯雅热病毒预计也将成为威胁。2012 年至 2014 年，在越南五个与老挝和柬埔寨接壤的省份，对因急性发热住院的患者进行了登革热和基孔肯雅热病毒监测。监测范围扩大到了患者家庭附近的蚊子。
共采集了 558 份人血清样本，1104 只成蚊和 2250 户家庭的 12041 只幼虫。在 17 份（3%）人血清样本和 9 只（0.8%）成蚊中发现了登革热病毒。在 2 只成蚊（0.18%）中检测到基孔肯雅病毒，而在人中未检测到基孔肯雅病毒。发现蚊子种群密度存在差异，其中与柬埔寨接壤的隆安省最高。尽管布雷蒂乌指数很高，人口密度很高，而且存在主要的跨境公路系统，但隆安省的感染率最低。在得农省发现的发病率最高，布雷蒂乌指数和容器指数第二低。在 5 只白纹伊蚊、3 只埃及伊蚊和 1 只库蚊中检测到登革热病毒。在 2 只埃及伊蚊中检测到基孔肯雅病毒。所有感染的蚊子都属于在世界其他地区描述的单倍型，在未感染的蚊子中发现了一些新的单倍型。
登革热病毒被认为是从柬埔寨定期传入越南的，主要是通过人的活动。这里报告的数据提供了一个补充的情况。由于国际贸易的密集，远距离运输的蚊子可能在通过胡志明市定期将登革热病毒输入越南方面发挥作用。了解越南蚊子的迁徙情况非常重要，不仅要了解老挝和柬埔寨边境的情况，还要了解国际贸易路线的情况。蚊子监测计划应针对蚊子种群，而不是蚊子种类。
