common and important viral diseases Flashcards
what is influenza
an acute viral infection of the repsiratory tract
what is the incubation period of influenza
1-3 days
what are potential complications from influenza
LRTI
admisson to hospital
death
what are risk conditions for influenza
chronic respiratory system diseases
CV
endocrine
hepatic
renal
neurological/neuromuscular
management of infleunza in risk groups
immunisation with inactivated influenza vaccine is important
exposure prophylaxis
empirical treatment pending results of PCR screen
treatment of influenza
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
what is respiratory syncitial virus
major cause of LRTIs in young children and adults
commonest cause of severe respiratory infection in infants
very infectious and spreads with ease
predisposing factors for RSV infection
- prematurity
- low birth weight
- congenital cardiopulmonary disease
- immunodeficiency
- maternal smoking
- male sex
- day care attendance
- overcrowding
- lack of breastfeeding
- low socio-economic status
- admission to hospital during RSV season
what family does RSV belong to
paramyoxoviridae
hiRSV transmission
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
histopathology of RSV
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
clinical symptoms of RSV
expiratory wheezing
cough and coryza
air trapping
nasal flaring
subcostal retractions
cyanosis
fever only in 50%
clinical symptoms of RSV
expiratory wheezing
cough and coryza
air trapping
nasal flaring
subcostal retractions
cyanosis
fever only in 50%
diagnosis of RSV
season, age, clinical manifestations
respiratory viral seasons and symptoms can overlap
lab tests - nasal swabs, nasopharyngeal aspirate, ednotracheal aspirate
recommendations for use of passive RSV vaccine
high risk due to bronchopulmonary dysplasia
high risk due to CHD
high risk due to SCID
treatment for RSV infections
supportive treatment - healthy children and adults
<1 - hospital, inspired O2 and IV fluids
immunocompromised - ribavirin
what are symptoms of coronaviruses
sore throat
dry cough
mild diarrhoea in children
rarely develops into pnemonia
arial droplets of SARS-CoV-2 transmission
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
other forms of transmission of sarscov2
hand to mucus membrane contact - viable for 3 days on solids, 1 day on cardboard, and only 3 hours in aerosolised
airborne
foecal-oral
symptoms of sarscov2
fever/chills
cough
SoB
fatigue
muscle or body aches
headache
loss of taste or smell
sore throat
songestin or runny nose
D and V
course of sarscov2
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
comorbididtes and risk factors of SARS
age
hypertension
diabetes mellitus
coronary heart disease
cerebrovascular disease
COPD
malignancy
immunosuppresion
diagnostic tests for sarscov2
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
treatment for sarscov2
no treatment for mild
antiviral thepray - molnupiravir, remdesivir
treat to target
