Cold & Flu + Anti-influenza therapy Flashcards
What are the causes of the common cold?
rhinovirus is the most common cause but also coronaviruses, respiratory syncytial virus and adenovirus
How is the common cold transmitted?
via nasal epithelium, airborne droplets, hand and fomites, virus attached to receptors in the throat
What are some typical symptoms of the common cold?
nasal obstruction, rhinorrhoea, sneezing, sore throat, mild fever, headache, myalgia
What effective treatment is available for the common cold and how do they work?
Zinc (reduces length of cold), paracetamol is an antipyretic and analgesic which reduces nasal obstruction, nasal decongestants such as pseudoephedrine, phenylephrine, Oxymetazoline and Xylometazoline work by stimulating alpha adrenergic receptors in blood vessels that supply URT causing a reduction in oedema and secretions making it easier to breath, oral antihistamine/decongestant/analgesics: histamine prevents sneezing, decongestant causes vasoconstriction and analgesics reduce headache and fever. NSAIDs may block inflammation which reduces symptoms
What is influenza and what are the types available?
Influenza is an acute respiratory illness resulting from infection with an influenza virus. Types are A viruses, B viruses and C viruses. B and C only infect humans and don’t cause pandemics
What are the symptoms of influenza?
fever, headache, muscle aches, severe weakness, respiratory symptoms such as cough, sore throat and difficulty breathing
How is influenza transmitted?
Inhalation of aerosols containing the virus which is produced by talking, cough and sneezing. Also transmitted by touching an infected person or item contaminated with virus then touching your eyes, nose or mouth
What effective treatment is available for flu?
vaccine as prophylaxis, drugs include M2 inhibitors such as amantadine and Rimantadine, NA inhibitors such as Relenza (zanamivir), Tamiflu (oseltamivir) & Nucleoprotein inhibitor such as Xofluza (Baloxavir)
What are some disease containment measures?
isolation, quarantine, self-shielding, social distancing
Describe the structure of the influenza virus
negative sense RNA virus, RNA copied to give positive sense, nucleocapsid consists of ssRNA, viral RNA polymerase, a nucleocapsid membrane derived from host and 2 glycoproteins Neuramidase and haemagglutinin
Why are amantadine and Rimantadine no longer recommended?
resistance occurs rapidly
What are the stages of viral replication?
attachment, entry by formation of fusion vacuoles, uncoating, macromolecular synthesis, assembly and release
What is Neuramidase?
a viral enzyme that cleaves haemagglutinin tether anchoring the virion to the infected host cell
What type of inhibitors are Zanamivir and oseltamivir?
Neuramidase inhibitors but also transition state inhibitors as they are analogues of sialic acid which is a natural substrate of NA inhibitors
How are Zanamivir and oseltamivir administered and why?
Zanamivir given by inhalation as its very polar and had poor bioavailability, whereas oseltamivir is an ester prodrug given orally and is converted to the free carboxylic acid in GIT
