Changing trends in intestinal parasitic infections among long-term-residents and settled immigrants in Qatar

Parasites & Vectors

Table 1 No of subjects in each category and the prevalence (%) of the four species of helminths by age, sex, region and year

		No Subjects	Hookworms	*T. trichiura*	*A. lumbricoides*	*H. nana*	Combined
Age class Age (years)
1	0-1	140	0	0	0	0	0
2	1.1 - 1.9	575	0	0	0.2	0	0.2
3	2.0 - 4.9	1084	0.1	0	0.1	0.1	0.3
4	5.0 - 9.9	903	0	0.1	0	0	0.1
5	10.0 - 14.9	423	0.2	0	0	0	0.2
6	15.0 - 19.9	297	1.0	0.3	0	*0.7*	1.7
7	20.0 - 29.9	1377	7.0*	*1.7*	*0.9*	0.3	*8.6*
8	30.0 - 39.9	1345	4.6	0.6	0.7	0.1	5.3
9	40.0 - 49.9	1259	1.4	0.6	0.6	0	2.3
10	50.0 - 59.9	835	0.5	0.4	0	0.1	1.0
11	60.0 - 69.9	521	0.6	0.4	0	0	0.8
12	70.0 - 79.9	336	0.3	0	0	0	0.3
13	> 79.9	113	0	0	0	0	0
χ ²			158.6	32.6	24.3	-	**
P			< 0.001	0.001	0.018	NS
Sex
	Males	5327	*3.4*	*0.7*	*0.5*	0.1	*4.2*
	Females	3881	0.2	0.2	0.1	0.1	0.4
χ ²			54.0	-	-	-	**
P			< 0.001	NS	NS	NS
Region
	Africa	1299	0.2	0.1	0.1	0.2	0.5
	Arabian Pen.	511	0	0	0	0.2	0.2
	Asia	3214	*5.7*	*1.4*	*0.9*	0.2	*7.2*
	Eastern Med.	874	0	0	0	0	0
	Qatar	3310	0.1	0	0	0
χ ²			154.5	62 .0	40.4	10.4	192.4
P			< 0.001	< 0.001	< 0.001	0.035	< 0.001
Year
	2005	2559	1.0	0.3	0.2	< 0.1⁺	1.3
	2006	2120	1.3	0.2	0.3	< 0.1⁺	1.7
	2007	2220	*3.1*	0.7	*0.5*	0	3.7
	2008	2309	3.0	*0.8*	0.3	*0.3*	4
χ ²			38.8	8.7	-	11.7	48.1
P			< 0.001	0.034	NS	0.008	< 0.001

*The highest prevalence in each category is in italics for emphasis.
+ In these cases there was just one infected subject.
** In this case see text for significant interactions between sex and age.
The statistical outputs were derived from minimum sufficient models, after first fitting all factors into a single full factorial model, and the degrees of freedom can be calculated from the number of levels within each factor minus 1. χ² values are not shown for non -significant terms because these had been removed from the model during backward elimination in the derivation of the minimum sufficient model. The χ² values for goodness of fit of the minimum sufficient models for hookworms, T. trichiura, A. lumbricoides and H. nana was as follows: 399.1 (dof = 838, P = 1), 368.9 (dof = 839, P = 1), 369.1 (dof = 842, P = 1) and 368.3 (dof = 851, P = 1), respectively. Additional terms in the final models, that did not incorporate the presence/absence of parasites are not shown, but can be made available on request from the authors.

ISSN: 1756-3305