elisaInfectious disease epidemiology
General information Risk factors/ causes Symptoms/ signs Treatment
Epidemiology: the study and The cause often known is an Infectious disease: Caused Koch’s postulates
analysis of the incidence, infectious agent is a necessary by an infectious agent. to identify the
distribution and control of cause. microbial cause of
diseases. Communicable disease: specific diseases
What is infectious disease Transmission- directly or
What is infectious disease epidemiology then used for? indirectly from an Microbes must be
epidemiology? Identification of causes infected person. present in every
- Humans of new, emerging case of the disease
- Infectious agents infections, e.g., HIV, Rotes of transmission but not in healthy
(helminths, bacteria, vCJD, Zika, SARS-CoV2 Direct organisms.
fungi, protozoa, viruses, Surveillance of Skin-skin: Herpes
prions. infectious disease. type 1 Microbe must be
- Vectors (mosquito, snails, Identification of source Mucous-mucous: isolated from a
blackfly) of outbreaks. STIs. disease host and
- Animals (dogs and sheep/ Studies of routes of Across placenta: grown in pure
goats, mice and ticks) transmission and Toxoplasmosis. culture.
natural history of Through breast
What is infectious disease infections. milk: HIV Disease must be
epidemiology? Identification of new Sneeze-cough: reproduced when
interventions. Influenza. a pure culture is
A case is a risk factor… Indirect: introduced into a
Infection in one person can be Food-borne: non-disease
transmitted to others Salmonella susceptible host.
Water-borne:
Hepatitis A. Microbe must be
Vector-borne: recoverable from
Malaria. an experimentally
Air-borne: Chicken infected host.
Timeline for infection pox.
Exposure: a relevant
contact – depends on the
agent.
Transmissible disease:
transmission- through
unnatural routes- from an
infected person.
Week 1
The difference between disease epidemiology and infectious disease epidemiology:
, Disease epidemiology Infectious disease epidemiology
Deals with one population (e.g., human) Two or more populations (e.g., human and
pathogen)
Risk that causes the disease – cases A case of a risk factor
Identifies causes e.g., cancer (radiation The cause often known
source)
Cancer is an example of the disease
epidemiology because something like
radiation causes the cancer.
Week 2
Wound infectious
General information Risk factors/ causes Symptoms/signs Treatment
Staphylococci In general – healthy people Reservoir – Antibiotic
facultative, non- don’t get serious staph humans sensitivity –
sporulating, non- infections. Asymptomatic sensitive to
motile, gram positive - Skin disease – carriage sites Penicillin,
cocci. increased - Nares metronidazole,
Cell division (3 colonisation (nostril clindamycin,
planes) – daughter - Trauma – expose or nasal tetracycline,
cells don’t fully binding sites passages) erythromycin
separate - forms - Viral respiratory - Rectum Resistant to
clusters tract infection - Perineum aminoglycosides –
(influenza) -expose (area e.g., kanamycin
binding sites - between and streptomycin
Decreased anus and
clearance genitals)
- Foreign Body - Pharynx
- Liver disease Skin
- Neoplasia (benign colourisation –
growth) brief, repeated
27 species – three - Diabetes Transmission –
important species - Renal Failure person to person
1. Staphylococcus - Leukocyte &
aureus – important Immunoglobulin
human pathogen Defects
2. Staphylococcus - Elevated Serum IgE
epidermidis – Levels
normal skin flora, - Narcotics Addiction
disease under - Broad Spectrum
special Antibiotic Therapy
circumstances.
3. Staphylococcus
saprophyticus –
UTI’s in young
females.
,Pseudomonas – Epidemiology – Found in soil, Diagnosis, treatment and
– Gram negative rod- P. aeruginosa is rarely part decaying matter, prevention
shaped of the microbiota – can moist Diagnosis can be
cause infections environments difficult
throughout the body once – Virulence Difficult to treat
inside. factors – due to multidrug
adhesins, toxins, resistance of P.
polysaccharides aeruginosa.
– Pathogenesis
- Infection
can occur
in burn
victims
- Bacteria
grow
under
the
surface
of the
burn
The bacteria kill
cells, destroys
tissue and
triggers shock.
Clostridium spps Clostridium form Lab characterisers: Antibiotic
Anaerobic endospores under adverse Large gram- sensitivity-
Spore-forming environmental conditions. positive rods sensitive to
Gram positive bacilli Spores- useful in Penicillin,
Mostly soil identification metronidazole,
saphrophytes Culture- blood clindamycin,
Potent toxins – agar tetracycline,
important in (anaerobically), erythromycin.
pathogenesis. selective media Resistant to
(add aminoglycosides –
aminoglycoside) e.g., kanamycin
and streptomycin.
, Respiratory infections continued
Important bacterial Infections of the respiratory tract
• URT: Upper respiratory tract infections
• LRT: Lower respiratory tract infections
General information Risk factor/ cause Symptoms/ signs Treatment
URT infection– whooping Caused by Bordatella Fever Effective antibiotic
cough (Pertussis) pertussis Malaise erythromycin or
Anorexia azithromycin
Rhinorrhea Vaccine
Sneezing DPT (Diphtheria,
Lacrimation Pertussis,
Conjunctivitis Tetanus)