Table 1 Prevalence (%) of helminth parasites in the study population in the first (2005–2008), second (2009–2011), third (2012–2014) periods and overall

 Hook worms

2.05 (1.763–2.342)

1.38 (1.136–1.623)

0.42 (0.307–0.556)

1.22 (1.097–1.348)

  Trichuris trichiura

0.49 (0.356–0.654)

0.42 (0.295–0.577)

0.13 (0.075–0.220)

0.33 (0.269–0.404)

  Ascaris lumbricoides

0.34 (0.229–0.478)

0.19 (0.112–0.308)

0.12 (0.068–0.209)

0.21 (0.162–0.271)

  Hymenolepis nana ^a

0.10 (0.045–0.186)

0.19 (0.112–0.308)

0.15 (0.088–0.242)

0.15 (0.106–0.198)

 Above 4 helminth spp. combined

2.63 (2.301–2.955)

2.01 (1.720–2.305)

0.76 (0.604–0.936)

1.72 (1.575–1.873)

  Strongyloides sp.

Nd

0.16 (0.087–0.266)

0.04 (0.014–0.104)

0.09 (0.057–0.148)

  Schistosoma sp.

Nd

0.06 (0.018–0.132)

0.07 (0.031–0.140)

0.06 (0.034–0.111)

 Taenia sp.

Nd

0.02 (0.003–0.082)

0.04 (0.010–0.091)

0.03 (0.011–0.065)

 Others combined^b

Nd

0.03 (0.007–0.099)

0.04 (0.014–0.104)

0.04 (0.017–0.079)

 All helminths combined^c

Nd

2.23 (1.920–2.535)

0.93 (0.757–1.113)

1.50 (1.336–1.672)