Environmental Health and Ecological Sciences Thematic Group, Ifakara Health Institute, Kiko Avenue, Mikocheni, PO Box 78373, Dar es Salaam, United Republic of Tanzania.
Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Socinstrasse 57, 4051, Basel, Switzerland.
Malar J. 2017 Oct 23;16(1):423. doi: 10.1186/s12936-017-2067-6.
Bed nets reduce malaria-related illness and deaths, by forming a protective barrier around people sleeping under them. When impregnated with long-lasting insecticide formulations they also repel or kill mosquitoes attempting to feed upon sleeping humans, and can even suppress entire populations of malaria vectors that feed predominantly upon humans. Nevertheless, an epidemiological study in 2012 demonstrated higher malaria prevalence among bed net users than non-users in urban Dar es Salaam, Tanzania.
Focus group discussions were conducted with women from four selected wards of Dar es Salaam city, focusing on four major themes relating to bed net use behaviours: (1) reasons for bed net use, (2) reasons for not using bed nets, (3) stimuli or reminders for people to use a bed net (4) perceived reasons for catching malaria while using a bed net. An analytical method by framework grouping of relevant themes was used address key issues of relevance to the study objectives. Codes were reviewed and grouped into categories and themes.
All groups said the main reason for bed net use was protection against malaria. Houses with well-screened windows, with doors that shut properly, and that use insecticidal sprays against mosquitoes, were said not to use bed nets, while frequent attacks from malaria was the main stimulus for people to use bed nets. Various reasons were mentioned as potential reasons that compromise bed net efficacy, the most common of which were: (1) bed net sharing by two or more people, especially if one occupant tends to come to bed late at night, and does not tuck in the net 71%; (2) one person shares the bed but does not use the net, moving it away from the side on which s/he sleeps 68%; (3) ineffective usage habits, called ulalavi, in which a sprawling sleeper either touches the net while sleeping up against it or leaves a limb hanging outside of it 68%. Less common reasons mentioned included: (1) Small bed nets which become un-tucked at night (31%); (2) Bed nets with holes large enough to allow mosquitoes to pass (28%); and (3) Going to bed late after already being bitten outdoors (24%).
Behaviours associated with bed net use like; bed sharing, bed net non compliant-bedfellow, sleeping pattern like ulalavi and some physical bed net attributes compromise its effectiveness and supposedly increase of malaria infection to bed net users. While some well-screened houses looked to instigate low malaria prevalence to non-bed net users.
蚊帐在人周围形成一道保护屏障，从而降低与疟疾相关的发病和死亡。当经过长效杀虫剂处理后，蚊帐还能驱赶或杀死试图吸食正在睡觉的人的蚊子，甚至能抑制主要以人类为食的疟疾传播媒介的整个种群。然而，2012 年在坦桑尼亚达累斯萨拉姆市进行的一项流行病学研究表明，在城市中，使用蚊帐的人与不使用蚊帐的人相比，疟疾的发病率更高。
在达累斯萨拉姆市四个选定的区进行了妇女焦点小组讨论，重点讨论了与蚊帐使用行为相关的四个主要主题：（1）使用蚊帐的原因；（2）不使用蚊帐的原因；（3）人们使用蚊帐的刺激或提醒；（4）使用蚊帐时感染疟疾的原因。采用框架分组的分析方法解决与研究目标相关的关键问题。对代码进行审查并分为类别和主题。
所有群体都说使用蚊帐的主要原因是预防疟疾。他们说，那些有很好纱窗、门能关紧且使用杀虫剂驱蚊的房子，不需要使用蚊帐，而经常受到疟疾的攻击是人们使用蚊帐的主要刺激因素。蚊帐效果受到多种因素的影响，蚊帐共享、一个人使用但不将其固定在床边、不恰当的使用习惯等都是常见原因。最常见的原因包括：（1）两人或多人共享蚊帐，尤其是如果一个人习惯深夜上床，并且不将蚊帐掖好；（2）一个人在床上，但不使用蚊帐，将其从睡的那一侧移开；（3）使用不当，即翻滚的睡眠者在靠着蚊帐睡觉时碰到它，或让四肢悬在外面。提到的不太常见的原因包括：（1）晚上不掖好的小蚊帐；（2）有足够大的洞让蚊子通过的蚊帐；（3）在外被叮咬后才上床睡觉。
与蚊帐使用相关的行为，如蚊帐共享、不遵守蚊帐规定的同床者、类似 ulalavi 的睡眠习惯以及一些物理蚊帐属性，都会降低其效果，增加使用者感染疟疾的风险。虽然一些纱窗很好的房子看起来能降低非蚊帐使用者的疟疾发病率。
