Chain of Infection. Dr. Mohamed El Bashaar. Causative Agent. Susceptible Host. Reservoir. Portal of Exit. Portal of Entry. Mode of Transmission. CAUSATIVE AGENTS:. A biologic agent/s capable of causing infectious diseases. Bacteria,Parasites , Fungi & Viruses. Reservoir.
Dr. Mohamed El Bashaar
Portal of Exit
Portal of Entry
Mode of Transmission
Bacteria,Parasites, Fungi & Viruses
Skin-to-skin contact, clothes, (folliculitis with Staphylococci or MRSA ,viral as HSV1)
Droplets during coughing, sneezing (common cold, flu, swine flu, pneumonia, bacterial meningitis), or kissing (infectious mononucleosis, cold sores)
Stool-to-mouth (fecal-oral) spread, usually via dirty hands or utensils (hepatitis A, Giardia, pinworms(oxyuris), cholera, poliomyelitis)
Spread from mother to fetus during pregnancy (hepatitis B, C, HIV, HSV-1, HSV-2, rubella, toxoplasma, varicella, syphilis, bird flu), or delivery (Chlamydia trachomatis, Neisseriagonorrheae, group B Streptococci=S.agalactiae)
An autoinfection – the spread of an infection from one body part to another, usually by hands or clothes (folliculitis, impetigo).
2. Waterborne Infections
By drinking contaminated water, one can contract, cholera, dysentery, typhoid fever, amebiasis & cryptosporidium . Tap water in hospitals may contain Legionella.
By swimming in contaminated swimming or spa pools, or lakes, intestinal parasite Cryptosporidium, eye and middle ear infections. Certain parasites may enter through the skin(schistosoma).
Water in public showers may hold Legionella;
Flood water may contain various pathogenic microbes
3. Airborne Infections
Industrial cooling or hot water systems, air condition can be a source of M. tuberculosis or Legionella
During walking barefoot, Clostridium tetani, or intestinal parasites, like Strongyloidesstercoralis or hookworms(Ancylostoma) can be contacted.
Eating with soil-contaminated hands can also result in infection by parasites.
5. Food-Borne Infections
Food poisoningis an infection of the gastrointestinal tract caused by microbes from contaminated food: bacteria like Salmonella or E.coli, toxins from Staphylococcus aureus or Clostridium botulinum or viruses like Enterovirus.
6. NosocomialInfections : Health-care acquired infections(HAI):
Usually caused by bacteria that are resistant to antibiotics (multi-drug resistant strains).
Urinary tract infections from urinary catheters (CA-UTI) .
Surgical-site infections (SSI).
Catheter related Blood stream infections(CR-BSI).
Ventilator associated pneumonia(VAP)
Fungal infections, in patients with low immunity.