6.3 identifying & controlling pathogen spread

importance of controlling outbreaks

to prevent

• communal threats to public health

• long term health consequences

• negative effect on the economy

physical methods to identify viruses

identify viruses based on size and shape

• X-ray crystallography

• electron microscopy

immunological methods to identify viruses

detect specific viral antigens or antibodies often using the ELISA technique (enzyme-linked immunosorbent assay)

molecular methods to identify viruses

locate specific genetic sequences or identifying RNA viruses

• situ hybridisation

• reverse techniques

• DNA sequencing

phenotypic methods to identify bacteria

identify particular traits or features in bacteria

• microscopy

genotypic/molecular methods to identify bacteria

locate specific genetic sequences or identify genetic profiles of specific plasmids

• gene probes

• sequence analyses

• plasmid fingerprinting

immunological methods to identify bacteria

detect specific antigens or antibodies

• monoclonal antibodies

• ELISA

• immunofluorescence

how a host of a pathogen is identified

index case - identifying the first individual to have the disease

reservoir - the habitat where the pathogen grows, lives and multiplies

life cycle of the pathogen - the stages of a pathogen’s development, from its initial replication to growth and spread

direct transmission

• person-to-person contact

• kissing or sexual contact

indirect transmission

• airborne droplets or particles

• contact with contaminated objects

• ingestion of contaminated food or water

• biological vehicles

• vectors

how the spread of a pathogen is determined

• monitoring the spread (WHO has different alert stages)

• using R0 values (basic reproduction number)

control of pathogen spread

prevention

• personal hygiene, sterilisation & isolation

• access to improved sanitation and clean drinking water

• vaccination to provide long term protection

surveillance

• global monitoring of disease outbreaks

modification of environment

• making the environment less suitable for microbes to grow and be transmitted

treatments of pathogen

medication

• antibodies for bacterial infections to treat infectious diseases

• antibiotics used to treat bacterial infections

• antiviral agents used to treat viral infections

modes of action of antibiotics

inhibition of

• cell wall synthesis

• protein synthesis

• nucleic acid transcription and replication

• enzyme activity

injury to the PM

modes of action of antiviral agents

preventing - vipers repeat pro rhetoric

• viral attachment / entry

• replication of viral genome

• protein synthesis

• release of new infectious virions