Emergence

Question 1

What are factors which are involved in increasing emerging viral infections?

Answer 1

Genetic variation

Population growth/ density

Population proximity to animals - e.g farming

Environment disturbance - humans expose to animals e.g deforestation

Climate change - movement of animals e.g birds/ mosquitoes

Travel by humans

Question 2

Avian influenza

Why is transmission to humans quite rare?

Answer 2

Avian influenza virions bind sialic acid (2,3)-galactose-terminated oligosaccharides, whereas the human influenza virus hemagglutinin proteins
bind tightly to oligosaccharides carrying a terminal (2,6)-
linked sugar.

Cells of the human respiratory tract do display (2,3)-galactose-terminated oligosaccharides, but such cells lie deep in respiratory tissues.

Conversely, sialic acid with terminal (2,6) linkages is abundant in the more accessible regions of the upper respiratory tract. This anatomical fact appears to be a prime reason why humans cannot be infected easily with avian influenza viruses.

Question 3

HIV was zoonosis

What are the original hosts for HIV1/ HIV2?

Answer 3

HIV1 - chimpanzee

HIV2 - sooty mangabey