New research on how best to eliminate STH infections of Kenyan school children.

A new paper published in Infectious Diseases of Poverty has identified that whilst more frequent deworming reduces infection amongst school-aged children, treatment programmes need to look beyond the school to achieve elimination.

14 February 2017

School-based deworming is widely implemented in various countries to reduce the burden of soil-transmitted helminths (STHs), however, the frequency of drug administration varies in different settings.

A new study investigates the relative impact of a single annual treatment and 4-monthly treatment on STH prevalence rates amongst Kenyan school children. Using this information it also assesses whether school based deworming alone is enough to eliminate STH infections.


In the 4-monthly treatment group, the proportion of children infected with hookworm decreased from 59.9 to 5.7%, while Ascaris lumbricoides infections dropped from 55.7 to 6.2%.

In the single treatment group, hookworm infections decreased over the same time period from 58.7 to 18.3% (12.6% absolute difference in reduction) and A. lumbricoides from 56.7 to 23.3% (17.1% absolute difference in reduction.

Residual hookworm infection among children on 4-monthly treatment were associated with male sex and baseline nutritional status, whereas A. lumbricoides infection was associated with individual and school-level infection at baseline, latrine cleanliness at schools.


The studies results show that 4-monthly treatments were more effective than a single annual treatment. Repeated treatments dramatically reduced the intensity of infections, but failed to completely clear STH infections among school children in Kenya.

This suggests that increasing the treatment frequency among school children alone may not be sufficient to interrupt transmission in such a community.

Such findings highlight the impact of periodic deworming for reducing the intensity of infections, but in order to reduce transmission in the community, the following should be emphasized:

  1. The need for integrating deworming with interventions that help reduce exposure to infections such as access to improved WASH at both school and household levels, and
  2. The value of expanding treatment to the entire community.

Visit our publications database to download 'Kepha, S. , Mwandawiro, CS., Anderson, RM., Pullan RL., Nuwaha F., Cano J., Njenga  SM., Odiere MR., Allen E., Brooker SJ., Nikolay B., (2017) 'Impact of single annual treatment and four-monthly treatment for hookworm and Ascaris lumbricoides, and factors associated with residual infection among Kenyan school children' Infectious Diseases of Poverty20176:30 DOI: 10.1186/s40249-017-0244-z