Coverage, use and maintenance of bed nets and related influence factors in Kachin Special Region II, northeastern Myanmar

In the last decade, there has been encouraging progress in malaria control and prevention. Factors such as economic development, urbanization, and largely unprecedented financial support have all contributed to the success in the fight against malaria [1]. However, malaria is still a major global public health problem. In 2010, the worldwide estimated number of new cases of malaria was 219 million. This resulted in 660,000 deaths. In Southeast Asia (SEA) alone, 32 million new cases, and 43,000 deaths are estimated for 2010 [2]. The Greater Mekong Subregion (GMS) is a very high-risk region for malaria. Around 70 % of the total population is at risk of contracting malaria and 26 % are in a high-risk area (i.e., reported incidence of more than one case per 1000 people per year) [3, 4]. Myanmar is one of the 31 highest burden malaria countries worldwide. Over the past three decades, the number of malaria cases and malaria-induced mortality in SEA has been highest in Myanmar [3, 5]. Importantly, malaria in Myanmar affects transmission in neighbouring countries too. This seriously impedes malaria elimination efforts in these countries [6]. The WHO Global Malaria Programme has recommended full coverage of long-lasting insecticidal nets (LLINs) in areas targeted for malaria prevention [7]. Also, scaling up appropriate use of insecticide-treated nets (ITNs) is a national policy in Myanmar aimed at preventing and controlling malaria. Implementation strategies include free delivery of LLINs and free treatment of mosquito nets already in use before the start of the peak transmission season. These interventions are aimed at ensuring that people living in high-risk malaria areas can protect themselves. The goal is that at least 80 % of people in moderate and high-risk areas are protected by ITNs/LLINs by 2015 [8]. Kachin State is a bordering region that is heavily forested area and has a high concentration of poor ethnic minorities. The malaria burden is particularly high and malaria outbreaks occur frequently. In 2005, the mortality rate of malaria was as high at 7.8 deaths per 1000 people [3, 5, 9]. However, coverage, use of bed nets, and other factors that influence malaria prevention and control have not been well studied among the war-torn population of Kachin Special Region II (KR2). The objective of this study was to research the coverage of both treated (ITNs and LLINs) and untreated bed nets, and also to determine which factors influence bed net use and maintenance. This field study was conducted from June to September 2013 during the high-risk season for contracting malaria.

In the Union of Myanmar, malaria is considered a leading cause of morbidity and mortality [8]. It is also the leading respondent-reported cause of death from community-based survey [15]. The goal of the new national strategic plan is to reduce malaria morbidity and mortality by at least 50 % against the baseline level of 2007 by 2015. Use of ITNs is widely recognized as a main effective intervention to prevent malaria. High use rates of ITNs are an important goal of many malaria programmes [16]. Another goal is that at least 80 % of the people in moderate- and high-risk villages among 180 selected townships should be using ITNs for protection against malaria. Ownership of at least one bed net per household is a main indicator used to assess outcomes. The results of this study reveal that ownership of bed nets is very high (99.7 %). A total of 1714 bed nets were reported amongst 668 households sampled; 77.5 % of bed nets were LLINs. The overall, bed net to person ratio was 1:1.96 while the LLIN to person ratio 1: 2.52 in the KR2 region. The high level of coverage is a result of the sixth and tenth rounds of GFATM for the China Malaria Programme, which distributed 35,297 free LLINs through Health Poverty Action (HPA) in KR2 in the past five years (2008–2013). Most (24,917) of the bed nets were delivered through the tenth round of GFATM during 2012–2013. When commercial sectors are responsible for bed net availability, the ownership is concentrated among the richest families [17]. Therefore, high bed net availability does not necessarily mean higher coverage [18]. Giving special attention to the poorest and the most vulnerable populations is essential to ensure universal access to LLINs. In order to ensure equity, the HPA GFATM team, in cooperation with village leaders, carried out a survey assessing both the household economic situation and bed net coverage before LLIN distribution. This ensured that the priority was given to the poorest and the most vulnerable households during the distribution campaign. The higher ownership of treated ITNs/LLINs among poorer families and the higher ownership of untreated bed nets among wealthier families show the effectiveness of the campaign. Free distribution of LLINs promoted the equity in LLIN ownership, and gave the war-torn population an essential human right.

Access to an ITN within the household is considered a much more accurate indicator of ITN use than simply owning an ITN [16]. People are at different levels of risk for complications from malaria. Pregnant women, particularly primagravida with malaria, have a high risk of malaria being associated with more serious illness and low birth weights [10, 19, 20]. The study shows a high rate of bed net use (97.3 %) among children (98.4 %) and females (98.6 %) in KR2. There was not a significant difference in use of bed net between adult females groups. However, it is important to note that pregnant females had higher use rate of ITNs or LLINs (78.6 %). This may be one of outcomes from the health behaviour and education interventions by the Chinese GFATM Malaria Programme. In the past five years, HPA delivered 390 sessions of community health education, with 29,759 attendees, to promote the use of bed nets in KR2. Side effects (smell, dizziness, headache, and itchiness) from LLIN insecticide were reported as a barrier for ITN utilization [21]. Only 57 (71.1 %) infants used LLINs because their parents or caretakers were afraid that the insecticide would be harmful. The side effect of insecticide is an issue that has received little attention from both academic and health authorities. Additionally, there have been incidents resulting from the use of LLIN insecticides during the implementation of malaria control programmes. For example, an outbreak of rash occurred in a school after LLIN distribution by a NGO in Mangshi City of Yunnan Province, China in 2009. More than 250 schoolchildren had itchy skin rash which resulted from allergic reaction to the insecticide in LLINs because the NGO did not teach the children to hang LLINs in ventilated places for 24 h before using them. Pyrethroid is usually used for treatment of bed nets and is relatively safe to humans. However strong smells and hypersensitivity of the eyes, skin, and respiratory system can occur; thus, safer insecticides should be developed for treatment of bed nets.

The MVLRA did not identify sex as an independent influence factor on use of ITNs/LLINs. The rate of use of ITNs/LLINs was the lowest (70.5 %) amongst adult males (≥15 years). Due to the war, most males are recruited into Kachin Independent Army. Therefore, they often go into the forest and back to their villages. They may carry malaria from the forest into their community. Further, it has been reported that males were more likely than females to have falciparum malaria infections (OR: 1.80; CI: 1.29, 2.54) in KR2 [22]. Bed net use within this community can prevent malaria transmission from the malaria-infected solders to civilians. Other measures, such as long-lasting insecticidal hammocks and topical and spatial repellents should be used by solders when they are in the forest [23‐25].

Several authors have pointed out that household socio-economic status influences bed net access, and is the strongest determinant of net use. Wealthier families are much more likely to use nets [11, 16, 18, 26‐28]. These data in KR2 are contrary to past studies. The poorest families were significantly more likely to SUITNPN than the wealthier families because of free distribution of LLINs in KR2. The free distribution of LLINs is also the result of lower bed net ownership among wealthier families (67.6 %). There is a so-called ‘diversion effect’ that untreated nets may divert mosquitoes from one person using an untreated net to an unprotected person in the same room. However, if the net is treated, there is evidence that the diversion effect does not occur because the insecticide offers some protection to the individual not using a bed net [10, 29]. The results showed that no residents used treated ITNs. Dipping existing nets and expired ITNs should be used in vector control measures for malaria prevention. The results of MVLRA showed that geographical zone, roof types, and family income sources were strongly associated with use of ITNs/LLINs. Families in the lowlands and foothills were significantly less likely to use ITNs and LLINs. The authors found that malaria prevalence is usually higher in lowland and foothill regions than mid- and upper hill areas. The MVLRA also identified that heads of households who knew that mosquitoes transmit malaria and that bed nets are the tool to prevent malaria were two independent factors for use of ITNs/LLINs. More than other vector control methods, ITN programmes largely depend on the acceptance and active involvement of communities. Involvement of communities in promoting use of ITNs also depends on their knowledge, perception, attitude, and behaviour towards nets [30, 31]. Knowledge, information and distribution of free bed nets are established as the first step towards encouraging ITN use [32]. As suggested by villagers and Health Department of KR2, interventions targeting health behaviour, and health education should be further strengthened in KR2.

The results showed that 1556 (90.8 %) of bed nets were owned for only two years, 158 (9.2 %) were owned for three years or more, and the mean calibrated HI was 1.33. The attitudes of heads of households towards fixing bed nets was an independent influence factor for net condition (F = 8.09, P = 0.0046). The amount of mice inside the household is significantly associated with bed net condition (F = 3.67, P = 0.0559). Not only is there a gradual loss of insecticide over time, but bed nets accumulate holes as a result of wear and tear. Both holes and loss of insecticide will reduce the protective effects of ITNs [10, 33]. When considering strategies to encourage behavioural changes, special attention should be given to education and what should be communicated [18]. Maintenance of bed net should be a behaviour change that is mentioned. During the interviews, respondents expressed concerns that the free LLINs were not strong enough. LLINs are easily torn and burnt by sparks from fire. They suggested that stronger bed nets should be distributed. Stronger fibres may ultimately be a more cost-effective option for the production and use of LLINs.

In spite of a 99.7 % ownership rate and 97.3 % (3262/3351) use rate of bed nets, with a 76.1 % (2551/3351) use rate of ITNs or LLINs, a malaria outbreak with 1093 confirmed malaria cases occurred in the lowland and foothill areas of KR2 during June and July 2013. The outbreak was finally controlled in August 2013 by using indoor residual spraying (IRS) of insecticides combined with standard anti-malarial treatment. The reasons of the outbreak in lowland and foothill areas may include (1) higher transmission intensity [34]; (2) higher population density and mobility; (3) lower proportion of ITN LLIN use, which was found to be 74.1 % (1951/2633) in lowlands and foothills versus 83.6 % (600/718) in mid and upper hills (Tables 3 and 5); and, (4) the principal vector, An. minimus, was found to bite people between nightfall and the time of people going to bed (about 22:00) in spite of its biting peak being from 23.00 to 01:00 [35], just as the respondents mentioned during interviews: “Bed nets cannot protect us from mosquito bites before we go to bed. Mosquitoes may bite the children when they play outdoors or are watching television. The feet, especially of children, may protrude out of the nets during sleeping”.

In 2014, the lesson from the previous outbreak was considered, and an IRS was carried out in late May 2014 when malaria incidence started to increase. This successfully prevented another outbreak. No significant benefit of combining LLIN and IRS compared with a background of LLIN coverage was documented in areas with low malaria vector density [36]. However, the combination of LLIN and IRS is effective to control potential outbreaks even when there is high LLIN coverage, and might be useful in settings of high malaria transmission. To ensure the success of vector control efforts, additional innovative strategies should be investigated [37, 38].

Study limitations include if demographic groups are not similar, bias might be introduced [39]. More females (524/668 = 78.4 %) were interviewed than males due to the fact that male heads of households are recruited into Kachin Independent Army and away from home during war time. This may cause selection bias and information bias. However, female heads of households should know about ownership and use of bed nets better than their husbands, meanwhile, the analysis adjusting for sex and age has been used to reduce the potential selection and information bias. Another limitation is that data on the number and/or type of net repaired, use of bed nets amongst children under five associated with increased MCHI have not been collected and assessed in this survey. Further survey on the issue may be valuable.

On the other hand, The National Malaria Control Programme (NMCP) of Myanmar hardly covers the KR2 because of the conflict between Kachin Independent Army and National Defense Army, therefore, 78.3 % (1342/1714) of the bed nets were from the sixth and tenth rounds of GFATM for China Malaria Programme. The GFATM stopped support China Malaria Programme in January 2014, and will not give further support to China. The existing LLINs will expire and they may be out of intactness within one year. Myanmar, China, and international societies should consider how to maintain the high coverage and use rate of bed nets, and other malaria control activities in KR2.

Despite the fact that NMCP of Myanmar hardly covers KR2, the coverage, and use rates of bed nets was high, especially among children, and pregnant women. The free distribution of LLINs from the sixth and tenth rounds of GFATM for the China Malaria Programme ensured that the poorest and most vulnerable populations obtained universal access to LLINs in KR2. FWI, geographical zones, household roofs, family income sources, and head of household’s knowledge of malaria transmission and prevention through the use of bed nets are independent factors which influence use of ITNs/LLINs. Finally, attitudes of heads of households towards fixing bed nets influenced the net intactness. Therefore, special attention to maintaining the high rate of bed coverage and use should be given to the war-torn population to ensure equity and their human rights.