Fundamentals of Microbiology

5.3.3 Portals of Entry: Transmission of infectious agents

 There are several modes by which pathogens are transmitted from a source to susceptible individuals. Pathogens gain access to the body through limited number of routes. These specific routes are known as portals of entry ports of entry include

Pathogens of gastrointestinal and genitourinary systems exit through body fluids or faeces. Pathogens of respiratory systems exit through nose, mouth fluids – during coughing, sneezing and speaking. 

- Respiratory tract – through aerosol

- Gastro intestinal tract – food, water and other contamination

- Genitourinary tract – sexual contact and poor hygiene

- Skin and wounds and paraenterel routes – include punctures injection, bites, cuts, surgical incisions and cracked skin.

Transmission of pathogenic organisms is effected by

1. Direct contact transmission ® by way of shaking hands, kissing, contact with sores, sexual contact, poor personal hygiene etc.

2. Direct faecal – oral route ® through unwashed hand into mouth

3. Indirect contact transmission ® through fomites (vehicles of transmission – include surgical instruments, bedding, eating utensils, blood, food, water, intravenous (IV) fluids etc.

Portals of exit - The sites at which microorganisms leave the body.