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Respiratory Viruses - Coggle Diagram
Respiratory Viruses
Influenza
sudden onset high temp. & debilitating systemic symptoms. IP 48 hrs
At risk groups: elderly, immunocompromised, pregnancy
Seasonal epidemics occur annually
Influenza A: water-based avian species
Influenza B: human
Influenza C: human
Influenza D: cattle
Influenza A: Haemagglutin (HA), Neuraminidase (NA), RNA polymerase. Wild aquatic birds = natural reservoir for all influenza A viruses. Evolves rapidly.
Acute Resp illness: sudden onset, high grade fever, chills, myalgia, malaise, weakness.
Diagnosis: molecular techniques- polymerase chain reaction (PCR), nasopharyngeal swab. Treatment: antiviral medication (oseltamivir & zanamivir)
Human Enteroviruses
9 EV species. A-H, J: Poliovirus- Group C. HRV A-C
Natural host= humans
transmitted via faecal/oral route & resp. droplets
IP 2-30days
Causes a range of illnesses: aseptic meningitis, myocarditis, rash, illness, hand. foot & mouth disease, neonatal sepsis
Diagnosed by PCR or culture
Pleconaril blocks virus binding & uncoating, reduced median duration of picornavirus colds, not licenced
Respiratory Syncytial Virus (RSV)
single stranded (ss)RNA virus, 2 groups (A & B)
Natural host = humans
transmitted by large particles
IP 3-6days
causative agent of bronchiolitis
Diagnosed by IF or PCR. Treatment: Ribavirin
Severe Acute Respiratory Syndrome (SARS)
airborne virus- spread through small droplets & indirectly via surfaces
Originated from Horseshoe bat (China)
Clinical Symptoms: fever, cough, fatigue, loss of taste/smell, sore throat, myalgia, headache, GI symptoms.
Severe; dyspnoea, hypoxaemia, pneumonia
Diagnosis: nasopharyngeal swab, PCR, RAT
IP 2-7 days
Human Rhinovirus (HRV)
Picornaviridae, ssRNA virus
3 groups (A-C), over 100 serotypes, Group C doesn't grow in culture.
Natural host = humans. Transmitted via aerosols
IP 1-4 days
Diagnosed by PCR. NO specific antiviral therapy. NO vaccine (too many serotypes)
Human Metapneumovirus (HMPV)
2 genotypes (A &B) 2 subgroups in each
Natural host = humans, transmitted by rep. secretions
IP 3-6days
Causes: LRTI, URTI, otitis media, wheezing
Diagnosed by PCR
Vaccine Selection
degree of antigenic similarity between virus strains & circulating viruses
age & immune status of pt.
method of culture for the vaccine virus
pt. history of infection
Human Parainfluenza Virus
4 major types (1-4)
IP 2-8 days
Acute laryngotracheobronchitis (Croup)
Diagnosed by PCR, treat with steroids
Human Adenovirus (HAdV)
7 species A-G (>65 types)
Transmitted by direct contact, aerosols, faecal-oral, ocular instruments
Causes: resp. illness, ocular infections, gastroenteritis, haemorrhagic cystitis
Live oral vaccine against types 4&7
Middle East Respiratory Syndrome (MERS)
Transferred to humans from infected dromedary camels
Clinical Symptoms: Asymptomatic, Mild Resp. Symptoms, Severe acute resp. disease, death, fever, cough, SOB, pneumonia, GI symptoms