Worm Count 2010

Poor health habits are prevalent in crowded dining commons.

Intestinal worms are a widespread problem in many developing countries. Approximately one quarter of the world’s population suffers from infection. Intestinal worms can lead to poor health and poor nutrition, both of which can lead to poor educational outcomes.


Although intestinal worms in rural China were once considered a major infectious disease, they appear to have dropped off China’s health “radar screen” because of its invisible nature and highest prevalence in remote, out-of-the-spotlight rural areas. When this disease is allowed to quietly fester, it can slowly eat away at the health of countless individuals and negatively affect national economic productivity.

Previous REAP studies suggest that as many as 39 percent of rural Chinese children suffer from iron deficiency, or anemia. Anemia, in turn, is often caused by intestinal worms that “steal” nutrients from food before the body can digest them. In addition to causing a variety of health problems, anemia has been shown to negatively affect educational outcomes by hindering cognitive ability and reducing attendance rates. Despite the high rates of anemia and the known link between anemia and intestinal worms, to our knowledge, no comprehensive rigorous study has been undertaken to determine the prevalence of intestinal worms in China.


REAP aims to determine the prevalence of intestinal worm infection in some of the poorest parts of rural China. Some related questions include: What factors are responsible for different regional prevalence rates? What types of intestinal worms are more prevalent than others? Who has worms? Have people who have worms now been treated in the past? By whom and how?


Testing sample

Six rural counties from Guizhou and Sichuan—three in each province—were randomly selected based on income level. A total of 95 villages and 46 schools within towns of each county were included. 1701 children were surveyed in total.

Data collection

Data collection was led by REAP with the help of the Chinese Center for Disease Control (CDC). Children’s height and weight measurements, family socioeconomic data, medication intake (of anti-helminth in the past 18 months), and fecal samples to test for worm type were obtained. 

Handing out stool sample containers to young kids to test for intestinal worms.

Data Analysis

  • An estimate of intestinal worm infection prevalence based on worm type and age
  • An identification of key factors driving different worm infection rates
  • An analysis of the effect on Body Mass Index (BMI)


Children’s height and weight measurements, family socioeconomic data, medication intake (of anti-helminth in the past 18 months), and fecal samples to test for worm type were obtained.


High rates of infection with wide variation according to location, age, and worm type

  • Guizhou has higher rates of infection than Sichuan by 30%. In Guizhou, fewer preschool-aged children are infected than school-aged children, suggesting that prevalence rates increase as children age. In Sichuan the opposite is true
  • In the two provinces combined, 21.2 percent of preschool-aged children and 22.9 percent of school-aged children were infected with one or more of the three types of worms tested for in the survey
  • The intensity of infection in both provinces for both age groups is lowest for whipworm while the highest infection rates appear among preschool-aged children with roundworm

Main factors for different rates of worm infection:

  • Lower maternal education and drinking unboiled water were the main determinants of infection and accounted for higher prevalence
  • Large number of siblings, not washing hands before meals, eating uncooked meat also contributed to differences in infection rates

Significant negative effects on BMI

  • Infection with one or more of the three types of worms (roundworm, hookworm, or whipworm) is associated with an average decrease in BMI of 18.3 percent

Limited efficacy of current deworming measures

  • Just under half of the sample population in both provinces had taken deworming medication. However, there is no significant effect of current deworming measures on worm infection based on high rates of reinfection


The above findings emphasize the importance of a long-term, consistent deworming regimen, which given the serious implications for the educational performance of those infected, has been approved by the government for official policy action. Having determined that current deworming measures are ineffective, REAP is currently designing a new study to identify a more effective strategy.

As there is little knowledge among rural clinics, schools and communities regarding risk factors for worm infection, health education may play an important role in the fight against intestinal roundworms in rural China.

In the coming months, we will be testing, among other strategies, a two-prong attack: first, focusing on educating village clinicians, parents and students about how to prevent infection, and then ensuring that deworming programs are rolled out regularly so that children remain worm-free. Stay tuned to see if we're on the right track!