Bradley John, Lines Jo, Fuseini Godwin, Schwabe Christopher, Monti Feliciano, Slotman Michel, Vargas Daniel, Garcia Guillermo, Hergott Dianna, Kleinschmidt Immo
MRC Tropical Epidemiology Group, London School of Hygiene and Tropical Medicine, London, UK.
Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK.
Malar J. 2015 Apr 21;14:170. doi: 10.1186/s12936-015-0679-2.
There have been many recent reports that the rate of outdoor biting by malaria vectors has increased. This study examined the impact this might have on malaria transmission by assessing the association between exposure to outdoor bites and malaria infection on Bioko Island, Equatorial Guinea.
Responses to questions about time spent outside the previous night from a malaria indicator survey were combined with human landing catch measurements of hourly rates of outdoor and indoor biting for the whole island to estimate the number of outdoor and indoor bites received by each survey respondent. The association between RDT measured malaria infection status of individuals and outdoor bites received was investigated.
The average number of bites received per person per night was estimated as 3.51 in total, of which 0.69 (19.7%) would occur outdoors. Malaria infection was not significantly higher in individuals who reported spending time outside between 7 pm and 6 am the previous night compared to those not spending time outside in both adults (18.9% vs 17.4%, p = 0.20) and children (29.2% vs 27.1%, p = 0.20). Malaria infection in neither adults (p = 0.56) nor in children (p = 0.12) was associated with exposure to outdoor bites, even after adjusting for confounders.
Malaria vector mosquitoes in Bioko do bite humans outdoors, and this has the potential to reduce the effectiveness of vector control. However, outdoor biting is currently not a major factor influencing the malaria burden, mainly because more than 95% of the population are indoors during the middle of the night, which is the peak biting period for malaria vector mosquitoes. The majority of resources should remain with control measures that target indoor biting and resting such as LLINs and IRS.
近期有许多报道称疟蚊户外叮咬率有所上升。本研究通过评估赤道几内亚比奥科岛户外叮咬暴露与疟疾感染之间的关联，来探究这可能对疟疾传播产生的影响。
将疟疾指标调查中关于前一晚在户外停留时间的问题回答，与全岛按小时计算的户外和室内叮咬率的人饵诱捕测量数据相结合，以估算每位调查受访者所遭受的户外和室内叮咬次数。研究了通过快速诊断检测测得的个体疟疾感染状况与所遭受的户外叮咬之间的关联。
估计每人每晚总共遭受的叮咬次数为3.51次，其中0.69次（19.7%）发生在户外。在前一晚晚上7点至次日早上6点期间报告在户外停留的个体中，疟疾感染率在成年人（18.9%对17.4%，p = 0.20）和儿童（29.2%对27.1%，p = 0.20）中均未显著高于未在户外停留的个体。即使在对混杂因素进行调整后，成年人（p = 0.56）和儿童（p = 0.12）的疟疾感染均与户外叮咬暴露无关。
比奥科岛的疟蚊确实会在户外叮咬人类，这有可能降低病媒控制的效果。然而，目前户外叮咬并非影响疟疾负担的主要因素，主要是因为超过95%的人口在午夜这一疟蚊叮咬高峰期时都在室内。大多数资源应继续用于针对室内叮咬和栖息的控制措施，如长效驱虫蚊帐和室内滞留喷洒。
