SH9: Microbial pathogenesis

Question 1

What is Pathology

Answer 1

Study of diseases -progress, causes, treatment

Question 2

What is Medical microbiology

Answer 2

Pathology of infectious diseases, caused by microorganisms, capable of being transmitted

Question 3

What are parasites?

Answer 3

Larger pathogens

Question 4

What is Virulence?

Answer 4

Ability of an organism to cause disease

Question 5

What are pathogens?

Answer 5

Microorganisms that cause disease

Question 6

What are opportunistic pathogens

Answer 6

Do not normally cause disease, and may be common in our bodies and are harmless (E. coli- lives harmlessly in GI tract, but causes infections if moved to the urinary tract) but may live in a host, but can cause disease under some circumstances. Also, can be an issue in those using immunosuppressant’s.

Question 7

What are obligate pathogens

Answer 7

evolved virulence factors (toxins) that cause disease, so cause disease as part of their life cycle. HIV causes AIDS and reduces the immunological defence of a host body.

Question 8

What are biofilms

Answer 8

Mixed communities of microorganisms. they are a mucilaginous surface community, they form on and in the human body (when you don’t brush your teeth). Biofilms can form on damage tissue, and infect the body, causes disease- they are difficult to treat.

Question 9

Transmission of disease from infected to non-infected host:

Answer 9

• Aerosols; coughing or sneezing (whooping cough)
• Faecal-oral; faeces by water or food (Norwalk virus)
• Vector-borne; by insects either externally or internally (malaria)
• Body contact
• Breast feeding
• Warts
• EBV –epstein barr virus
• Sexually transmitted disease
• Animals
• Vertical transmission; the spreading from parent to child

Question 10

What is needed in order to cause disease?

Answer 10

Transmission is not sufficient to cause disease, pathogen need to breach the hosts’ defence mechanisms (immune system).

Question 11

What are the common stages in the progress of infection?

Answer 11

• Contact; transmission from infected person
• Incubation period; no symptoms, pathogen reaches site of infection and reproduces
• Prodromal period; general symptoms indicates pathogen is winning the competition against the bodies defence
• Acute phase; specific symptoms appear
• Crisis; body temperature rises to a dangerous level to try and fight pathogen, death is possible
• Decline period; if you survive, balance swings in favour of immune system, prevents virus replicating. Repair damage tissues
• Convalescence; restoration of normal health