Table 2. Observed (O) and expected (E) species density frequency distributions of helminths in human hosts.

Study [reference]	O/E	total (n)	n = 0	n = 1	n = 2	n = 3	n = 4	n = 5	n = 6	n = 7	X2 Statistic	p-value
Wong et al., 2016 [84]	O	33	1	8	15	9					0.063	0.996
	E		1	8	16	9
Gordon et al., 2015 [51]	O	545	10	85	196	188	66				4.434	0.3504
	E		6	81	208	191	59
Hu et al., 2015 [54]	O	1403	1363	39	1	0					0.598	0.8968
	E		1362	41	0	0
Ferreira et al., 2015 [47]	O	444	121	131	168	21	3	0	0		55.577	<0.001*
	E		81	204	142	17	1	0	0
Vonghachack et al., 2014 [82]	O	729	81	172	276	169	31	0	0	0	48.268	<0.001*
	E		44	210	301	152	20	1	0	0
Sanchez et al., 2013 [70]	O	320	88	129	76	27					47.863	<0.001*
	E		62	164	83	10
Odiere et al., 2012 [68]	O	4064	1398	2356	296	13	1				1.769	0.778
	E		1399	2342	312	11	0
Muller et al., 2011 [63]	O	156	17	51	76	11	1				10.949	0.027*
	E		9	65	72	10	0
Anah et al., 2008 [39]	O	350	176	133	39	2					10.783	0.013*
	E		162	159	28	1
Tengco et al., 2008 [77]	O	1990	879	797	293	21					139.413	<0.001*
	E		762	1016	206	6
Jardim-Botelho et al., 2008 [56]	O	196	14	51	94	37					2.057	0.561
	E		10	56	93	37
Fleming et al., 2006 [48]	O	1332	231	294	554	253	0	0	0	0	186.136	<0.001*
	E		116	458	547	209	5	0	0	0
Briand et al., 2005 [43]	O	474	327	140	7	0	0				0.574	0.966
	E		329	136	9	0	0
Tchuem Tchuente et al., 2003 [76]	O	1044	102	287	358	286	11				72.745	<0.001*
	E		60	293	458	229	5
Thiong'o et al., 2001 [78]	O	3158	1017	1219	654	225	43				130.172	<0.001*
	E		891	1356	732	166	13
Brooker et al., 2000 [44]	O	1738	146	462	542	485	103				132.655	<0.001*
	E		79	451	726	414	69
Lili et al., 2000 [58]	O	766	190	302	197	77					41.157	<0.001*
	E		162	344	218	42
Scolari et al., 2000 [72]	O	236	113	69	53	1					37.366	<0.001*
	E		94	111	30	1
Widjana et al, 2000 [83]	O	2394	312	689	995	381	17				218.714	<0.001*
	E		175	843	1088	284	4
Toma et al., 1999 [79]	O	654	60	239	241	114					20.663	0.001*
	E		49	234	287	84
Booth et al., 1998 [41]	O	1539	3	91	541	904					7.352	0.061
	E		2	74	579	884
Needham et al., 1998 [64]	O	543	8	43	233	259					18.919	<0.001*
	E		2	48	240	252
Albonico et al., 1997 [38]	O	3497	1	167	979	2350					68.350	<0.001*
	E		2	99	1123	2272
Booth et al., 1996 [42]	O	1276	45	563	569	99					0.975	0.807
	E		50	558	562	105
Upatham et al., 1989 {[81]}	O	1142	92	326	444	280					194.919	<0.001*
	E		34	250	570	188
Upatham et al., 1989 [81]	O	518	17	125	277	99					11.208	0.011*
	E		11	119	308	80
Holland et al., 1987 [53]	O	140	77	30	20	12	1				74.177	<0.001*
	E		56	61	21	2	0
Higgins et al., 1984 [52]	O	1387	325	418	368	276					275.53	<0.001*
	E		194	550	499	144
Ismid et al., 1981 [55]	O	158	15	51	79	13					5.375	0.146
	E		10	59	80	9
Sinniah et al., 1978 [73]	O	150	27	54	56	13					2.372	0.499
	E		23	63	52	12

* Indicates statistical significance (p<0.05)