Question

2. List one microbe that can cause the following:

Common cold ______________________________________________________

Sinus infection _______________________________________________________

Middle ear infection _____________________________________________________

Scarlet fever ___________________________________________________

Diphtheria ______________________________________________________

Answer 1

Common cold - Rhinovirus.
• This is viral infection of upper respiratory tract ( nose and throat).
• This is generally harmless and resolve itself in few days.
• It can be spread by droplets and contact.

Sinus infection - Bacteria like- Streptococcus pneumoniae and Haemophilus influenzae.
Fungi like - Aspergillus.
• This is inflammation of nasal cavity.
• This inflammation results into obstruction of sinus drainage system. This leads to mucus retention and decreased mucociliary clearance, which helps in bacterial growth.

Middle ear infection/ Otitis media - Streptococcus pneumoniae (Commonest).
• This can be a result of previous cold, allergy or respiratory infection.
• There may be pus formation in middle ear and tympanic membrane may also rupture.

Scarlet fever - Streptococcus pyogenes.
• It is result of previous sore throat and caused by toxin of st. pyogenes.
• Toxin causes a local inflammatory response which results into skin rashes.

Diphtheria - Corynebacterium diphtheriae.
• This is infection of mucous membrane of nose and throat.
• Toxin of bacteria causes necrosis in mucous membrane and forms pesudomembrane.
• It spreads via droplets and saliva.