Term
| Define horizontal transmission. |
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Definition
| From one person to another in the same generation. |
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Term
| Define vertical transmissi.on |
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Definition
| Between mother and fetus/ baby. |
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Term
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Definition
| A virus that is spread from a non-human animal to a human often via a biting arthropod vector. |
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Term
| What viruses cause chickenpox, measles and smallpox and by what mechanism are they transmitted? |
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Definition
Chickenpox: varicella zoster
Measles: paramyxoviridae
Smallpox: variola.
All are transmitted by the respiratory route. |
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Term
| What is the main cause of infections by the fecal-oral transmission mechanism? |
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Definition
| Ingestion of fecally contaminated food or water. |
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Term
| Name 2 picornaviruses which can be contracted from sewage contaminated water. |
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Definition
| Poliovirus and hepatitis A. |
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Term
| Describe how rubella can be transmitted. |
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Definition
-Normally spread horizontally by the respiratory route causing a mild rash or a sub-clinical infection
-Can cross the placenta (vertically) and cause fetal death and serious congenital malformations. |
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Term
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Definition
| Zoonoses transmitted via a biting arthropod. |
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Term
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Definition
| The severity of the disease caused by different viruses. |
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Term
| What are pathogenicity factors? |
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Definition
| The characteristics of the virus that allow them to be pathogenic. |
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Term
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Definition
| The severity of disease caused by different strains of the same virus. |
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Term
| What is the difference between primary and secondary viraemia? |
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Definition
| In primary viraemia the virus enters the blood and spreads to regional lymph nodes and around the body. It is then re-released back into the blood and goes on to produce a secondary effect. |
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Term
| What is meant by the term incubation period? |
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Definition
| The time period between viral exposure and symptoms becoming apparent. |
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Term
| How long are short, medium, long and very long incubation periods? |
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Definition
Short: < 7 days (localised infections- influenza)
Medium: 7-21 days (generalised infections- measles
Long: weeks to months (generalised- Hep A
Very long: years (SSPE measles). |
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Term
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Definition
| The time period between viral exposure and an individual becoming infectious to others. |
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Term
| Define reproduction number. |
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Definition
| The number of subsequent infections in a susceptible population caused by a viral illness in one individual during its infective period. |
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Term
| What is subacute sclerosing panencephalitis (SSPE). |
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Definition
| A rare complication of measles (1 in 100 000). The virus becomes established in the brain and it is fatal after a 2-6 year incubation period. |
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