Flaviviridae and Togaviridae

+ssRNA viruses

infections caused by a group of viruses spread to people by the bite of infected arthropods (insects) such as mosquitoes and ticks.

Yellow fever virus YVC

Dengue fever is the most frequent infectious disease transmitted by mosquitos

2013: Severe dengue ≈500k, case mortality: <1% (WHO) if good care

In 2017: 100m cases, 40k (17–49) deaths worldwide

• Zika was on the rise until 2016

1. Receptor-mediated endocytosis

2. Low pH in late endosome triggers membrane fusion

   
   

   5. Replication in ER pouches that are open to the cytoplasm

1. Full-length (–) RNA synthesized, new (+) RNA synthesized

2. C protein binds viral (+) RNA

3. Immature virus particle buds through ER

4. Particles are transported through the secretory pathway while they mature – prM and E are glycosylated

   – proteins rearranged (low pH) – prM is cleaved

5. - 11. Travel in vesicles

6. exocytosis

• DNA vaccine

• whole purified inactivated virus

• ….. more and more

(Tick-borne encephalitis virus)

German: FSME (Frühsommer-Meningoenzephalitis)

• inactivated vaccine recommended for persons at risk

• Adults and children, individual risk assessment

• 3 vaccinations, later one vaccination every 3–5 years

• ● Infection mostly asymptomatic

• ● Disease has 2 phases: flu-like, then neurological

• ● 2nd phase: Meningitis, encephalitis, myelitis

• ● If CNS (central nervous system) is involved, 1% mortality

Elimination of Rubella virus should be possible (Kretsinger 2017) Still ≈100,000 cases of CRS worldwide per year (Lambert 2015)

Rubella virus is of possible zoonotic origin