Lecture 20. Virus Entry, Spread & Exit Flashcards
What are susceptible cells?
Expresses the specific receptors that are recognised by a specific virus through specific VAPs
What are resistant cells?
Has no receptor - it may or may not be able to support viral replication
What are permissive cells?
Contains the proteins and molecules within the cell that are necessary for replication to occur
What are non-permissive cells?
Does not support viral replication, it may or may not be susceptible
What are common portals of virus entry?
Conjunctiva
Respiratory tract
Gastrointestinal tract
Skin
Genital tract
Congenital infection
What sized droplets are the ones that transmit infection most easily?
Middle sized
Where are viruses contained in larger droplets deposited?
Upper respiratory tract
Where are viruses contained in smaller droplets deposited?
Lower respiratory tract
What are the conditions of the gastrointestinal tract?
Harsh
Stomach acidity
Low pH
Digestive enzymes
Bile in the intestines
What are viruses that can infect the GI tract?
Norovirus
Rotavirus
Adenovirus
HAV
Poliovirus
How is spread favoured in the GI tract?
Poor sanitation and poor personal hygiene
What causes most of the viral eye infections?
Herpes simplex virus type 1 and several of the human adenoviruses
How are eye infections transmitted?
Transmission is believed to occur on the accidental introduction of virus
What must viruses that infect via genital tract overcome?
Local barriers to infection, such as mucus and the low pH of the vagina
How can the skin get infected?
Trauma or inoculation
Medical procedures (sharing needles, HBC, HBV)
Insects or animal bites (rabies, yellow fever)
What can in utero vertical transmission (during pregnancy) cause?
Rubella & CMV
What can perinatal transmission (during birth) vertical transmission cause?
Neonatal HSV
What can postnasal transmission (after birth) vertical transmission cause?
HIV
What is vertical transmission?
Vertical transmission refers to the transfer of virus from the mother
What viruses cause localised infections?
Rhinovirus and HPV
What viruses cause systemic infections (cause infections in different areas)?
Measles and poliovirus
What is the portal of exit for HPV?
Skin-to-skin contact
What is the portal of exit for rhinovirus?
Respiratory secretions
What is the portal of exit for poliovirus and rotavirus?
Faeces
What is the portal of exit for HIV and HSV?
Genital secretions
What is the portal of exit for adenovirus?
Tears
What does viremia mean?
The presence of virus in the blood
Is a common occurrence of infection with several viruses e.g HIV and hepatitis
Such viruses are transmitted through blood
What does uraemia mean?
The presence of virus within the urine
Occurs with several systemic viral infections
Hantavirus is shed in the urine and droppings of infected rodents
It is transmitted to people through aerosolise of virions, Human-to-human transmission of hantaviruses has not been documented yet
