Polio and Influenza Lecture Review

Flashcards covering the causative agents, symptoms, vaccinations, and epidemiological characteristics of polio and influenza based on the lecture transcript.

What is the medical name for the infection commonly known as polio?

Poliomyelitis

Which specific cells in the central nervous system are damaged by the poliovirus, potentially leading to paralysis?

Motor neurons

In which two countries has wild type polio recently seen an increase in cases according to the transcript?

Afghanistan and Pakistan

Why is polio classified as an enterovirus despite it not attacking the cells of the GI tract?

It is transmitted by the fecal oral route and enters the body through the mucosal membranes of the GI tract.

What virus family does polio belong to, and what does the prefix of this name indicate?

It belongs to the pornoveridae (Picornaviridae) family; the prefix Pico means very small, as the virus is only $30\,nm$.

Is the poliovirus an enveloped or non-enveloped virus?

Non-enveloped (or naked) RNA virus

What does it mean for polio to be a cytolytic virus?

It lyses the host cells as part of its replication cycle, which destroys the neurons.

What percentage of polio infections are estimated to be asymptomatic or result in minor flu-like symptoms referred to as polio minor?

$90\%$ to $95\%$

What term describes the condition when the poliovirus enters the blood?

Viremia

Which layers of the central nervous system are affected in non-paralytic polio, leading to muscle spasms and back pain?

The meninges (protective coverings around the brain and spinal cord)

What is the specific name for the polio infection when it involves the muscles that control respiration?

Bulbar oleoellitis (Bulbar poliomyelitis)

What condition might survivors of wild type polio experience $30$ to $40$ years after their original infection?

Post polio syndrome

What type of vaccine was developed by Jonas Salk in 1955?

Inactivated whole agent vaccine

What is a disadvantage of an inactivated whole agent vaccine like the Salk vaccine?

It requires booster vaccinations to maintain a robust immune response and lifelong immunity.

What type of vaccine was created by Albert Sabin in 1961?

Oral vaccine made from live attenuated (weakened) virus

What is a major disadvantage of the Sabin live attenuated vaccine?

The virus can mutate and revert back to a disease-causing form, and it is risky for immunocompromised individuals.

Which virus family causes influenza?

Orthomyxoviridae

Which two types of influenza are responsible for human respiratory epidemics?

Influenza a and b

What is the structural classification of the influenza virus?

An enveloped single stranded RNA virus

Within what timeframe must flu antivirals be administered to have the greatest effect?

Within $48$ hours of the onset of symptoms

What are the two main glycoproteins found on the surface of the influenza virion?

Neuraminidase (n) and Hemagglutinin

What is the function of the neuraminidase (n) protein in influenza?

It hydrolyzes mucus to allow access to cellular surfaces and acts as an enzyme to help the virion release from the host cell via budding.

What is the function of the hemagglutinin protein in influenza?

It binds to lung cells for attachment and causes endocytosis of the virus.

How many subtypes of hemagglutinin (HA) and neuraminidase (N) are there for influenza A?

$16$ subtypes of HA and $9$ subtypes of N

What is antigenic drift in the context of influenza?

Mutations in the n and proteins that occur during replication, leading to seasonal changes in the virus.

What is antigenic shift and why is it dangerous?

It occurs when two different strains (e.g., human and avian) reassort in a host to create a new highly virulent strain for which humans have no immunity.

What phenomenon killed many healthy young adults during the 1918 flu pandemic?

Cytokine storm (over-activation of the immune system leading to lung tissue damage)

What are cytokines?

Signaling molecules released from tissues to activate the inflammatory response and the immune system.

What occurs when a secondary bacterial pneumonia spreads to the bloodstream and causes multi-organ failure?

Septic shock

What is an adjuvant, as used in the inactivated subunit influenza vaccine?

A pharmaceutical additive that stimulates immune cells to take up the antigen and release cytokines for a robust response.