Causes
of H. pylori infection:
H. pylori is global, with a prevalence of 30-60%, more in the developing
countries than in the developed countries. The sole source of H. pylori is the human gastric mucus. The exact mode of
transmission H. pylori is not known, it seems to be spread from
person to person by saliva, and most people who are infected become
infected as children. It also has the potential to be spread by fecal contamination,
so it is likely to be oral-oral or fecal-oral route of transmission. This may
explain why the rate of infection is so high in poorer countries and in
socio-economic groups characterized by crowded living conditions, poor sanitary
conditions, and lack of clean water. Personal hygiene is also very important
since food preparers who may not perform adequate hand washing may be potential
sources of infection. With improvements in lifestyle, the prevalence of
childhood infections has declined in the developed countries.
After being ingested, the bacteria burrow through the protective
mucosa that lines the stomach to attach to deeper layers of the stomach, where
they can reside for years without causing symptoms.
Symptoms:
The majority of people who are infected with H. pylori are
symptom and disease free. For those who do have symptoms, gastritis and ulcers
are the results of an H. pylori infection. These illnesses are
characterized by:
- Upper abdominal pain.
- Loss of appetite.
- Nausea and vomiting, fatigue.
- If severe enough, bleeding into the gastrointestinal tract. Chronic atrophic gastritis may be seen in the later stages.
Abdominal pain is usually described as a burning sensation in the
central upper abdomen below the ribs. It may be associated with bloating,
burping, and loss of appetite. Often the symptoms occur after eating, and many
times patients waken in the early morning hours with abdominal pain.
If there is enough inflammation, bleeding is possible from the
stomach lining or from an ulcer, a small crater-like area in which the
inflammation has caused the protective lining of the stomach to wear away.
Symptoms of bleeding include vomiting
blood and passing black, tarry stools. The black stools are a result of blood
that has been metabolized and partially digested.
The ubiquity of H. pylori infection and its ability to evade
host immune response has led to speculation that this infection might be
associated with nongastro-intestinal tract disorders. The evidence for most
nongastrointestinal tract diseases is weak due to uncontrolled or poorly
controlled observations. Iron deficiency anaemia (IDA) may indeed be a
reflection of H. pylori infection,
at least in children; case reports show resolution of IDA with eradication of
the infection. H. pylori possesses
genes with iron-scavenging function which allow it to acquire iron from its
host.
