common and important viral diseases

Question 1

what is influenza

Answer 1

an acute viral infection of the repsiratory tract

Question 2

what is the incubation period of influenza

Answer 2

1-3 days

Question 3

what are potential complications from influenza

Answer 3

LRTI
admisson to hospital
death

Question 4

what are risk conditions for influenza

Answer 4

chronic respiratory system diseases
CV
endocrine
hepatic
renal
neurological/neuromuscular

Question 5

management of infleunza in risk groups

Answer 5

immunisation with inactivated influenza vaccine is important
exposure prophylaxis
empirical treatment pending results of PCR screen

Question 6

treatment of influenza

Answer 6

2 neuraminidase inhibitors - oseltamivir and zanamivir

work on surfaces of viruses
inhibit neuraminidase enzymes from attaching to virus so the infleunza virus cannot detatch itself from the respiraotry tract

Question 7

what is respiratory syncitial virus

Answer 7

major cause of LRTIs in young children and adults
commonest cause of severe respiratory infection in infants
very infectious and spreads with ease

Question 8

predisposing factors for RSV infection

Answer 8

1. prematurity
2. low birth weight
3. congenital cardiopulmonary disease
4. immunodeficiency
5. maternal smoking
6. male sex
7. day care attendance
8. overcrowding
9. lack of breastfeeding
10. low socio-economic status
11. admission to hospital during RSV season

Question 9

what family does RSV belong to

Answer 9

paramyoxoviridae

Question 10

hiRSV transmission

Answer 10

small inoculum is necessary to infect
transmitted by respiratory secretions - direct contact, via fomites, and large droplets
has been recovered from environmental surfaces near infected patients for up to 6 hours
entry through contact with nasal mucosa or eyes
incubates for 2-8 days

Question 11

histopathology of RSV

Answer 11

earliest lesion to occur within 24 hours of onset is necrosis of the bronchiolar epithelium with denudation of ciliated epithelial cells
subsequently lymphosytes migrate to affected tissue
submucosa and adventitia become oedematous
increased secretion from mucous producing cells
plugs consisting of mucous, cellular debris, and fibrin strands occlude the smaller bronchioles

Question 12

clinical symptoms of RSV

Answer 12

expiratory wheezing
cough and coryza
air trapping
nasal flaring
subcostal retractions
cyanosis
fever only in 50%

Question 12

clinical symptoms of RSV

Answer 12

expiratory wheezing
cough and coryza
air trapping
nasal flaring
subcostal retractions
cyanosis
fever only in 50%

Question 13

diagnosis of RSV

Answer 13

season, age, clinical manifestations
respiratory viral seasons and symptoms can overlap
lab tests - nasal swabs, nasopharyngeal aspirate, ednotracheal aspirate

Question 14

recommendations for use of passive RSV vaccine

Answer 14

high risk due to bronchopulmonary dysplasia
high risk due to CHD
high risk due to SCID

Question 15

treatment for RSV infections

Answer 15

supportive treatment - healthy children and adults
<1 - hospital, inspired O2 and IV fluids
immunocompromised - ribavirin

Question 16

what are symptoms of coronaviruses

Answer 16

sore throat
dry cough
mild diarrhoea in children
rarely develops into pnemonia

Question 17

arial droplets of SARS-CoV-2 transmission

Answer 17

incubatoin 2-10 edays
symptoms onset media 4-5 days from exposure
high viral shedding occurs early in disease
prolonged shedding seen
reinfection and asymptomatic cases both possible

Question 18

other forms of transmission of sarscov2

Answer 18

hand to mucus membrane contact - viable for 3 days on solids, 1 day on cardboard, and only 3 hours in aerosolised
airborne
foecal-oral

Question 19

symptoms of sarscov2

Answer 19

fever/chills
cough
SoB
fatigue
muscle or body aches
headache
loss of taste or smell
sore throat
songestin or runny nose
D and V

Question 20

course of sarscov2

Answer 20

week 2: 15-20% develop severe dyspnoea due to viral pneumonia requiring hospitalisation
week 2-3: in hospitalised ultimately 1/3 need ITU care
can rapidly decline from mild hypoxia to frank ARDS

Question 21

comorbididtes and risk factors of SARS

Answer 21

age
hypertension
diabetes mellitus
coronary heart disease
cerebrovascular disease
COPD
malignancy
immunosuppresion

Question 22

diagnostic tests for sarscov2

Answer 22

nose and throat swab for RT-PCR
endotracheal fluid for RT-PCR
POCT: RT-PCR
LAMP
antigen tests - lateral flow
Anti-N antibody, anti-S antibody

Question 23

treatment for sarscov2

Answer 23

no treatment for mild
antiviral thepray - molnupiravir, remdesivir
treat to target

Question 24

what family is HIV

Answer 24

retroviridae
genus - lentivirus

Question 25

transmission of HIv

Answer 25

blood
semen and vaginal secretions
breast milk
mucous membranes
contaminated needles
IV drug use

Question 26

symptoms of HIV

Answer 26

fever
pharyngitis
headache
myalgia
arthralgia
malaise
non-pruritic, maculopauplar rash on face and trunk

Question 27

systemic and organ manifestations of HIV

Answer 27

derma: pruritus, seborrheic dermatitis, popular pruritic eruption, eosinophilic folliculitis

CNS: HIV dementia complex

Peripheral NS: distal symmetric polyneuropathy; toxic neuropathy, inflammatory demyelinating polyneuropathy

Respiratory: interstitial pneumonitis, lymphocytic interstitial pneumonitis

Mouth: xerostomia, aphthous stomatitis

Blood: anaemia, neutropenia, hyperglobulinaemia

Question 28

what is a CD4 count used for

Answer 28

measures state of persons immune function

approx. 500-1300

Question 29

how are viroloigcal tests used for HIV

Answer 29

• Serological diagnosis (‘HIV Test’): 4th generation test-combines antibody/antigen detection;
• HIV RNA virus load after serology:
  
  • Detects the amount of virus present - high viral loads increase risk for disease progression & HIV transmission
  • Monitors effectiveness of ART - Goal of therapy is an undetectable viral load
  • Used during acute infection to detect virus
  • Measured by HIV-1 RNA RT-PCR

Question 30

5 Cs of testing services

Answer 30

consent
confidentialty
counselling pre and post testing
corrrect test results
connection

Question 31

management of HIV

Answer 31

no cure
- Effective antiretroviral drugs (ARVs) can control the virus and prevent onward transmission
- If an HIV-positive person adheres to an effective ART, the risk of transmitting the virus to their uninfected sexual partner can be reduced by 96%
- Oral Pre-exposure prophylaxis (PrEP) of HIV is the daily use of ARVs by HIV-negative people to block the acquisition of HIV;
- Post-exposure prophylaxis (PEP) is the use of ARVs within 72 hours of exposure to HIV to prevent infection

Question 32

antiretroviral treatment for HIV

Answer 32

• ARVs are divided into 6 classes, each of which blocks HIV in a different way
  
  • Nucleoside reverse transcriptase inhibitors (NRTIs)
  • Non-nucleoside reverse transcriptase inhibitors (NNRTIs)
  • Protease inhibitors (PIs)
  • Integrase inhibitors (INSTIs)
  • Fusion inhibitors (FIs)
  • Chemokine receptor antagonists (CCR5 antagonists)

Question 33

what si AIDS

Answer 33

development of HIV in the absence of treatment
median time from acquisition of HIV-1 infection to AIDS is approximately 8-10 years
loss of 30-60 CD4+ cells/ul per year in the absence of treatment
primarly chracterised by opportunistic infections