Contexto de la evaluación

10

8

-6 ^-

4

Age group (year)

* Male rate —0— Female rate

Mae Sariang, Thailand, Oct-Nov'91.

4.4.1.3 Use of untreated bednet i) Number, size and material

The first census survey during January to March 1990 revealed that m ost • households already possessed bednets. The total number of bednets was 1,596. The average number of persons/bednet was 2.9. After the first and second distribution of bednets, numbers of bednets increased to 2,251 and 2,606 in 1990 and 1991 respectively (Table 4.4). The number of persons /bednet decreased to 2.1 and

Only 9% of the existing bednets were nylon. Cheap nylon bednets were bought from a bednet company in Thailand and sold through the bednet fund scheme at a subsidised price. This made the proportion of nylon bednets considerably greater during the second survey. However, these nylon bednets were easily torn in the conditions of the Karen households. Therefore, most of them were badly tom in a later year. Most o f the remaining nylon bednets were stronger and more expensive. They were bought independently from markets.

ii) Prevalence of bednet use

During the census surveys, a question was asked on whether a household member slept under a bednet the night before each survey. The answers were ’yes’, ’no’ or ’not known, due to absence’. The latter were excluded from the analysis of prevalence of bednet use. The resulting prevalence reflects the cross- sectional view of how bednets were used in the village. The prevalence of bednet use were 61%, 86% and 94% during the dry and late rainy seasons of 1990 and 1991 respectively. Table 4.5 shows the prevalence of bednet use by age, sex and the availability of bednet in each household from the census surveys. Males, people of 10-19 and more than 59 years of age consistently used bednets less than the others.

The number of bednets available in each household was significantly related to the prevalence of bednet use (p<0.00001 by chi-square test for a trend). The latter finding suggests that the main obstacle to the use of bednets is availability to the villagers.

When the availability subsequently increased, due to the distribution of bednets before each census survey, the prevalence of bednet use also increased (p<0.00001).

However, the absolute prevalence rates could be overestimated because villagers would tend to please interviewers. In households with no nets, the rates of 0 - 6%

prevalence may reflect the approximate size of this over-estimation.

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Table 4.5 Prevalence (%) of bednet use in each survey,

c) Prevalence by availability of bednet in each household.

Number of

iii) Social surveys on malaria illness and bednet use These were structured questionnaire interviews of 279

households randomly selected from the total households in the study area, in May and December 1990. The heads of household were interviewed about their knowledge, attitudes and behaviour of malaria illness and the use of bednets.

a) Knowledge and attitude to malaria illness

a.4 Experience of malaria illness Never 75%

b.2 What are the advantages of sleeping under a

b.4 Preventive measures before the first use Sleeping besides a fire 37%

Having unused bednets for guests 16%

b.6 Any overnight guests during the last rainy

- Reasons were dusty, heavy contamination by infant defecation and urination.

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c) Use of bednets in farm huts

Households without farm huts 32%

Households with farm huts 68% the third census survey during September to October 1991, when all bans had enough bednets. Table 4.6 shows that when it is affordable, a household prepares bednets for 3 main purposes, using them in the household (73%), keeping some of them for guests or later use (19%), and keeping some of them in the farm hut for regular use away from the household (8%). The second proportion (19%) is higher than that from the previous survey (16%) (see 1.3.3.b.5 above). The third proportion (8%) is the same as before (see 1.3.3.C.4; 68% o f all households had farm huts and 12% of farm huts

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having bednets kept them in permanently, 12% out of 68% is equal to 8.2%). The overnight within each household for 2 consecutive nights in each month, for 4 months.

The observers brought and used their own bednets. They slept in common parts of the household to avoid the disturbance caused to the sleeping habits of the household members. Apart from the observation schedules, the observers also visited the bans from time to time for other research purposes. The household members had a good relationship with the observers. However, to minimise the possible bias from the introduction of the observers into the households, only 259 person-nights records from the last 2 months were analysed.

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i) General observations

Ban no.25 was located in a forest hilly area, with difficult access and not enough bednets. The household in this ban had separate bedrooms. However, during the observation period, household members did not use the bedrooms. They slept in the kitchen. The Karens had this habit as a part of their way of life. This is because they had no bednets and a fire in the kitchen was used both for warming and preventing mosquito bites. Ban no. 15 was located lower in the forest fringe area and more accessible. It had a bednet fund and had just received bednets from the research team in May 1990, before the observation. The household members slept in separate larger wooden houses with corrugated iron roofs.

ii) Sleeping time and use of bednet

Figure 4.4 shows the sleeping time of household members in both bans. About 86% of the total household members were staying in the household (see Annex 2.5). Most of them went to bed after 21.00 and got up after 6.00. The use of bednets in Ban 15 was significantly higher than in Ban 25 (p<0.05). This suggests that the use of bednets can be increased by improving the affordability of them. Figure 4.5 shows that young people of 10-29 years go to bed the latest and sleep least under bednets. Males go to bed later and sleep less under bednets than female (Figure 4.6) but these are not statistically significant.

iii) Activities outside bednets

There were many reasons keeping people outside bednets during the night time. With about 10% of the total person-nights people went away from the ban and did not come back to sleep during the night. Most of the reasons were for visiting friends or attending traditional festival in other bans, when they stayed overnight with their friends and returned to the household in the morning. Among the others who stayed in the household, there were many reasons keeping them outside

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