Question

what is the mechanism of transmission of most of the infections of the lower digestive system?

Answer 1

The lower digestive system refers to the gastrointestinal tract. A wide range of infection includes bacterial infection caused by a various strain of bacteria, some of them are Staphylococcus aureus, S. enterica, S.typhi etc.

Basically, bacteria infect by its toxins which may be secreted by them in the guts or in the food before ingestion. Some enterotoxins are so powerful that they are heat stable and are also not destroyed by the acid condition of the stomach. These enterotoxins cause activation of T-cells thus leading to symptoms like vomiting, fever, etc.

As for bacteria, they may either be in cyst form or matured form. And as they reach to the intestinal wall, they penetrate it and continue to grow and multiply themselves. They easily persist inside the phagosomes of macrophages causing the inflammatory response in the body.With the help of macrophages, they enter into the blood stream and lymphatic system and infect the other parts of the body.

The inflammatory response and activation of T-cells cause symptoms like dehydration, fever, vomiting etc.

These bacteria via stools and fluid infect the other water reservoir and when another person comes in contact with it, he/she gets infected.