Christina Johnson

H. Pylori contaminated water sources as a risk factor for gastric carcinoma among Peruvians

Location: Lima, Peru

Helicobacter pylori infection is a known carcinogen; it is the leading cause of gastric cancer globally, and a great area of concern in developing countries. The transmission of H. pylori is not definitively known, however is thought to be fecal-oral with contaminated water sources serving as environmental reservoirs. This Gram-negative, microaerophilic bacterium inhabits areas of the stomach, causing inflammation leading to gastritis, dyspepsia, ulcers and an increased risk for gastric carcinoma. Many of those infected, nearly 80%, are asymptomatic. Eradication of the bacteria in hosts seems to be an effective way to reduce gastric carcinoma; however, since the exact method of transmission is not known, there are not recommendations for avoiding infection. The study of the route of transmission of H. pylori will assist in primary prevention of gastric carcinoma.

The objective of the proposed research is to examine the relationship between H. pylori contaminated water and location and the clinical manifestation of chronic and/or recurrent infection. Analysis of water samples from different areas of Lima will allow us to pinpoint areas where water sources are contaminated. Samples will be collected from taps in homes and public buildings. Using PCR analysis, H. pylori cells will be identified and quantified. In addition, we will be collecting information from homes about the usage of water and practices (such as using a filter, boiling, etc).
Patients will be identified from the area of Lima where water samples are collected and will be evaluated medically, given questionnaires, and biopsied by gastroscopy. This will allow us to determine if there is a link between H. pylori in the water and that in the stomachs of patients.


  • Identify water sources of patients
  • Collect water samples
  • Review records to ensure that eligible cases are being enrolled in the study
  • Quality control and review of study instruments
  • Collect data from questionnaire on SES factors, water drinking habits, etc.

About Christina
Christina is from La Porte, Indiana, and graduated from Purdue University with a B.S. in General Health Sciences and a minor in Spanish. Christina graduated from the University of Michigan School of Public Health in May 2012 with a Master's in International Health Epidemiology. Her public heath interests lie in epidemiology of cancer from infectious origins.