Role of seasonal variation on the prevalence and risk factors of trichuriasis among the aboriginal community in Malaysia

Fig. 1

Other intestinal parasites detected among the aboriginal community during wet and dry seasons_

Intestinal parasites	Number of infection (%)		Association with T. trichiura infections
	Wet season (N=256)	Dry season (N=217)	Wet season (N=256)		Dry season (N=217)
			χ2	p-value	χ2	p-value
Ascaris lumbricoides	81 (31.6 %)	54 (24.9 %)	32.460	<0.001**	22.882	<0.001**
Hookworm	59 (23.0 %)	73 (33.6 %)	23.614	<0.001**	27.544	<0.001**
Giardia lamblia	53 (20.7 %)	18 (8.3 %)	3.430	0.064	8.069	0.005**
Entamoeba spp.	56 (21.9 %)	53 (24.4 %)	2.412	0.120	2.267	0.132
Blastocystis spp.	55 (21.5 %)	38 (17.5 %)	1.940	0.164	0.162	0.688
Chilomastix mesnilii	2 (0.8 %)	1 (0.5 %)	1.618	0.203	0.575	0.448
Dientamoeba fragilis	2 (0.8 %)	0 (0.0 %)	2.511	0.113	NA	NA
Endolimax nana	21 (8.2 %)	7 (3.2 %)	2.359	0.125	1.529	0.216
Entamoeba coli	10 (3.9 %)	5 (2.3 %)	2.535	0.111	0.595	0.441
Iodamoeba butschlii	11 (4.3 %)	7 (3.2 %)	0.004	0.950	1.529	0.216

Prevalence and significant difference of Trichuris trichiura infections during the wet and dry seasons_

Wet season (n=256)			Dry season (n=217)			Significant difference between the two seasons
Number of infections	Prevalence (%)	95 % CI	Number of infections	Prevalence (%)	95% CI	Z-score	p-value
142	55.5	49.2, 61.7	138	63.6	56.8, 70.0	1.792	0.073

Univariate analysis of the risk factors associated with Trichuris trichiura infections in the aboriginal community during wet (n=256) and dry (n=217) seasons_

Variables	Wet season (n=256)		Dry season (n=217)		OR (95% Cl)		p-value
					Wet season	Dry season	Wet	Dry
	Prevalence	(95% Cl)	Prevalence	(95% Cl)
Age
<15	58; 22.7 %	17.7, 28.3	53; 24.4 %	18.9, 30.7	1.690 (1.420,2.135)	1.496(1.283, 3.869)
>15	84; 32.8 %	27.1,38.9	85; 39.2 %	32.6, 46.0	1	1	0.143	0.014*
Gender
Female	77; 30.1 %	24.5, 36.1	63; 29.0 %	23.1,35.6	1.994(1.606,2.630)	0.703 (0.404, 1.225)
Male	65; 25.4 %	20.2,31.2	75; 34.6 %	28.3,41.3	1	1	0.980	0.213
Number of household
members
>8	93; 36.3 %	30.4, 42.6	78; 35.9 %	29.6, 42.7	1.967(1.544, 3.718)	1.722 (1.412,2.265)
<8	49; 19.1 %	14.5, 24.5	60;27.7 %	21.8, 34.1	1	1	0.909	0.255
Monthly household
income
≤ RM500	90; 35.2 %	29.3,41.4	88; 40.6 %	34.0, 47.4	1.511 (1.294, 3.891)	1.021 (1.575, 1.813)
> RM500	52; 20.3 %	15.6, 25.8	50; 23.0 %	17.6, 29.2	1	1	0.017*	0.944
Education level
No formal education
Primary and secondary education	37; 14.5% 105; 41.0%	10.4, 19.4 34.9, 47.3	40; 18.4% 98; 45.2 %	13.5, 24.2 38.4, 52.0	1.451 (1.266, 5.764) 1	1.935(1.511,2.712) 1	0.003**	0.828
Occupation
Rubber tapper, farmer	140; 54.7 %	48.4, 60.9	97; 44.7 %	38.0,51.6	3.889 (1.770,9.648)	1.788(1.005, 3.180)	0.078	0.047*
Professional, factory	2; 0.8 %	0.1, 2.8	41; 18.9%	13.9, 24.8	1	1
Water supply
Untreated tap water	101; 39.5%	33.4, 45.7	95; 43.8 %	37.1,50.7	1.857(1.105, 3.120)	2.154(1.219, 3.807)
from river and wells							0.019*	0.008**
Governmental tap water	41; 16.0%	11.8,21.1	43; 19.8%	14.7, 25.8	1	1
Usage of stored river
water
Yes	75; 29.3 %	23.8, 35.3	60; 27.7 %	21.8, 34.1	1.539(1.937,2.530)	1.072 (1.613, 1.876)
No	67; 26.2 %	20.9, 32.0	78; 35.9 %	29.6, 42.7	1	1	0.088	0.807
Latrine system/
defecation
No latrine system, river	140; 54.7 %	48.4, 60.9	135; 62.2 %	55.4, 68.7	1.892 (1.311, 11.519)	1.022 (0.997, 1.048)
Flush toilet and pit latrine	2; 0.8 %	0.1, 2.8	3; 1.4%	0.3, 4.0	1	1	0.482	0.187
Wash hand after
playing with soil
No	16; 6.3%	3.6, 10.0	9; 4.2 %	1.9, 7.7	0.907 (0.423, 1.947)	0.543 (0.206, 1.430)
Yes	126; 49.2 %	42.9, 55.5	129; 59.4%	52.6, 66.0	1	1	0.802	0.211
Wash hand after
defecation
No	7; 2.7 %	1.1, 5.6	5; 2.3 %	0.8, 5.3	1.687 (1.241, 1.955)	0.705 (0.184,2.705)
Yes	135; 52.7 %	46.4, 59.0	133; 61.3%	54.5, 67.8	1	1	0.480	0.609
Defecation area
River, bushes	66; 25.8 %	20.5,31.6	67; 30.9 %	24.8, 37.5	1.737 (1.043,2.893)	2.120 (1.203, 3.736)
Flush toilet and pit latrine	76; 29.7 %	24.2, 35.7	71; 32.7%	26.5, 39.4	1	1	0.033*	0.009**
Animals rearing
Yes	89; 34.8 %	28.9,41.0	81; 37.3%	30.9, 44.1	1.621 (1.983,2.674)	1.968(1.551,2.698)		0.908
No	53; 20.7 %	15.9, 26.2	57; 26.3 %	20.5, 32.7	1	1	0.058
Educational status of
father
No formal education	67; 26.2 %	20.9, 32.0	41; 18.9%	13.9, 24.8	1.591 (0.960,2.635)	1.862 (1.475,2.561)
Primary and secondary education	75; 29.3 %	23.8, 35.3	97; 44.7 %	38.0,51.6	1	1	0.071	0.623
Educational status of
mother
No formal education	62; 24.2 %	19.1,29.9	39; 18.0 %	13.1,23.7	1.434(1.863,2.383)	1.021 (0.551, 1.890)
Primary and secondary education	80; 31.3%	25.6, 37.3	99; 45.6 %	38.9, 52.5	1	1	0.164	0.948

Multivariate analysis of the risk factors of Trichuris trichiura infections in the aboriginal community during wet (n=256) and dry (n=217) seasons_

Variables	OR (95% CI)		p-value
	Wet season	Dry season	Wet	Dry
Age	NA	1.317 (1.396, 4.381)	NA	0.653
≤15
Monthly household income
≤ RM500	1.545 (1.304, 3.979)	NA	0.042*	NA
Education level
No formal education	1.440 (1.195, 2.997)	NA	0.049*	NA
Occupation
Rubber tapper, farmer	NA	1.435 (1.768, 2.683)	NA	0.258
Water supply	1.362 (1.030, 4.414)	2.253(1.996, 5.095)	0.426	0.049*
Untreated tap water from river
and wells
Defecation area
River, bushes	2.740 (1.184, 6.339)	1.513 (1.474, 4.834)	0.019*	0.485