The exact mechanisms involved in how H. pylori bacterium enters the body are not yet entirely known, but it is agreed that it is transmittable from person-to-person. The agreed means of transmission is via direct (oral-oral or faecal-oral) contact with substances where the bacterium can live and thrive such as saliva, gastric juice faecal matter or vomit. Contamination of water and food are also believed to be means by which the bacterium can be spread through exposure or direct contact.
Although studies have been able to test for and identify the bacterium in these transmissible substances, some argue that these have only been determined using adult participants and more research is needed to determine transmission factors in those of a younger age. This is because many believe that H. pylori infection acquisition is most typical during childhood, and likely contracted from an infected person that a child lives with.
H. pylori bacterium is extremely sensitive to atmospheric oxygen pressure, temperatures outside of the 34 to 40°C (93 to 104 °F) range and a lack of nutrients. This has also prompted researchers to be more inclined to believe the mode of transmission to be direct person-to-person contact – oral to oral or faecal to oral.
Good hygiene practices have thus been stressed by medical professionals, especially proper handwashing when handling food (the bacterium has been noted to be able to live for a short time on refrigerated foodstuffs) or after using the bathroom.
Once the bacterium enters the stomach it produces urease to neutralise gastric (stomach) acids in order to survive. It then penetrates the mucous lining of the stomach where it binds to cell receptors within the epithelial cells, colonising and infecting the walls of the stomach and/or duodenum. It causes a release of enzymes and toxins that damage the host’s tissue cells and triggers an immune system response that results in inflammation. Over time, this contributes, along with various other factors, to the development of intestinal health problems, such as gastritis, duodenitis, and the formation of peptic ulcers.
As a result of determined transmission causes (i.e. coming into direct oral contact with contaminated food, water or bodily fluids and faecal matter), the following are risk factors for H. pylori infection:
- Lack of good hygiene habits
- Residing in a location with many people in one spot (crowded living conditions – often associated with developing countries where unsanitary living conditions are more prevalent, or when serving in the army or living in nursing home facilities)
- Residing in an area without a reliable supply of purified / clean running water or adequate sewage systems
- Residing with a person who has an H. pylori infection