Summary
Summary Infectious Diseases (all lectures)
- Course
- Institution
Summary Infectious Diseases. All lectures included (with figures)!
[Show more]
Seller
Follow
gertjanzutphen
Content preview
Infectious DiseasesGert-Jan Wiggers
,LE 1 – Introduction course Infectious Diseases
Infectious diseases
Infectious diseases are caused by pathogenic microorganisms, such as bacteria, viruses, parasites or
fungi; the diseases can be spread, directly or indirectly, from one person to another. Zoonotic diseases
are infectious diseases of animals that can cause disease when transmitted to humans.
What does an infectious agent need to do to infect the host?
1. Attachment entry into body: evade natural protective and cleansing mechanisms → entry
(infection)
2. Local or general spread in the body: evade immediate local defences → spread
3. Multiplication: increase numbers (many will die in the hose, or en route to new hosts) →
multiplication
4. Evasion of host defences: evade immune and other defences long enough for the full cycle in
the host to be completed → avoid killing by host defences
5. Shedding from body (exit): leave body at a site on a scale that ensures spread to fresh hosts
→ transmission
6. Cause damage in host: not strictly necessary but often occurs → pathology, disease
Common transmission routes
Respiratory or salivary spread, facial-oral spread and sexual spread.
• Skin: cold sore – herpes simplex virus; lesions – varicella zoster virus; warts – papillomavirus
• Milk: HVI, HTLV (both retroviruses)
• Blood: HIV, Hepatitis B and C virus
• Placenta: Rubella virus, cytomegalovirus, Zika virus
Horizontal vs Vertical transmission
• Horizontal transmission: person on person
• Vertical transmission: infection of next
generation (birth)
• Zoonoses: transmission from animals
- vector (biting arthropod
- vertebrate reservoir
- vector-vertebrate reservoir
What is a virus?
Obligate intracellular parasites or symbionts that possess their own genomes encoding information
required for virus reproduction and, thence, a degree of autonomy from the host genetic system, but
do not encode a complete translation system or a complete membrane apparatus.
Important terms
• Virion: (physical) virus particle
• Capsid: protein shell surrounding viral nucleic acids
• Nucleocapsid: capsid + nucleic acid
• Envelope: lipid membrane that surrounds the capsid (note that not all viruses are enveloped)
,General scheme virus replication cycle
1. Attachment to receptor on cell surface
2. Entry
3. Virus uncoating: virus enter cytoplasm
4. Replication
5. Assembly: capsids form around nucleic acid
6. Release: budding forms envelope
Key concept in virus classification
All viruses must make mRNA that can be read by host ribosomes.
Baltimore classification:
Baltimore classification is important to recognize to which class a virus belongs to and to know more
or less which steps are involved in the replication cycle. In addition you can think of a method to
tackle the virus.
Virus taxonomy
• Realm
• Order
• Family
• Genus
• Species
• Virus
Viruses within family / genus are not transmitted the same way, nor do they cause the same
diseases. Conversely, viruses form different families may cause similar symptoms.
, Detection of viruses
1. Diagnosis for patients with suspected virus infection
2. Fundamental virology/immunology research
3. Epidemiological research
4. Surveillance
What are the qualities of a good (diagnostic) test?
• Sensitive: few false positive
• Specific: few false negative
• Fast
• Cheap
• Easy to perform
Direct vs indirect laboratory diagnostics
Direct: detection of…
• Whole organism (infectious particle)
• Their structural components
- viral proteins
- genetic material
• Their products
- mostly relevant for bacteria/fungi
Indirect: detection of…
• Antibodies targeting microorganisms in serum of a patient
- IgG/IgA
Direct measures
• Detect (infectious virus particle
- culture based techniques
- (electron) microscopy
• Detect viral antigen (e.g., envelope protein)
- antigen ELISA
- fluorescence microscopy
- lateral flow assay
• Detect genetic material
- PCR
- sequencing
How small are viruses?
Detectable with light microscope and electron microscope.
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller gertjanzutphen. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $7.84. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
85443 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now