Intestinal parasite infections and associated risk factors in communities exposed to wastewater in urban and peri-urban transition zones in Hanoi, Vietnam

Table 4 Prevalence and intensity of parasite infections among the participants enrolled in the cross-sectional survey in Hanoi, stratified by five exposure groups in the Than Tri district, Hanoi, between April and June 2014

Prevalence of infection/Exposure groups^a	Com _peri-urban		Com _urban		Farmer _peri-urban		Farmer _urban		Worker _HSDC		Chi-square test
	N = 101		N = 170		N = 129		N = 153		N = 128		Chi-square test
	n	%^d	n	%^c	n	%^c	n	%^c	n	%^c	P-value
Intestinal parasite^b	7	6.9	17	10.0	39	30.2	17	11.1	13	10.2	< 0.001
Soil-transmitted helminth^c	6	5.9	16	9.4	39	30.2	15	9.8	11	8.6	< 0.001
Intestinal protozoa	1	1.0	1	0.6	2	1.6	2	1.3	2	1.6	0.932
Hookworm	4	4.0	6	3.5	32	24.8	11	7.2	5	3.9	< 0.001
Light infection (1–1,999 epg)	4	4.0	6	3.5	32	24.8	11	7.2	4	3.1	< 0.001
Moderate infection (2,000–3,999 epg)	0	0.0	0	0.0	0	0.0	0	0.0	1	0.8
Trichuris trichiura	2	2.0	9	5.3	7	5.4	4	2.6	9	7.0	0.281
Light infection (1–999 EPG)	2	2.0	9	5.3	7	5.4	4	2.6	8	6.3	0.384
Moderate infection (1,000–9,999 epg)	0	0.0	0	0.0	0	0	0	0	1	0.8
Ascaris lumbricoides	0	0.0	2	1.2	0	0	0	0	2	1.6	0.252
Light infection (1–4,999 epg)	0	0.0	2	1.2	0	0	0	0	1	0.8	< 0.001
Moderate infection (5,000–49,999 epg)	0	0.0	0	0.0	0	0	0	0	0	0.0	< 0.001
Giardia intestinalis	0	0.0	1	0.6	0	0	0	0	1	0.8	0.612
Entamoeba coli	0	0.0	1	0.6	1	0.8	2	1.3	1	0.8	0.833
Entamoeba histolytica/E. dispar	0	0.0	0	0.0	0	0.0	0	0.0	0	0.0	na
Balantidium coli	1	1.0	0	0.0	1	0.8	0	0.0	0	0.0	0.403

^aExposure groups: Com _peri-urban: people living in the peri-urban commune Duyen Ha, 5 km away from the city along the Red River; Com _urban: people living in the urban area of Hanoi, in Bang B village or Tam Hiep commune along the To Lich River and potential exposed to wastewater; Farmer _peri-urban: peri-urban farmers living in Duyen Ha commune using the irrigation water from Red River, wells or local drains, which are not contaminated with the city’s wastewater; Farmer _urban: urban farmers living in Bang B village or Tam Hiep commune reusing wastewater from To Lich River; and Worker _HSDC: workers from Hanoi Sewerage and Drainage Company (HSDC) maintaining drainage channels and operating the Yen So treatment plants
^bIntestinal parasitic infection includes: Ascaris lumbricoides, Trichuris trichiura, hookworm and any intestinal protozoa
^cSoil-transmitted helminth infection includes: Ascaris lumbricoides, Trichuris trichiura, hookworm
^dPrevalence rate is calculated out of the results of the examination of a single stool sample by means of duplicate Kato-Katz and the formalin-ether concentration method, infection intensity by the examination via duplicate Kato-Katz
Abbreviation: epg, eggs per gram; na, not applicable

ISSN: 1756-3305