Infectious Disease And Evolution

Question 1

Malaria background (3)

Answer 1

Protozoan parasite (5 species)

More than 400,000 deaths per year mainly in Africa

Reproduce asexually and carried by mosquito

Question 2

P. Falciparum (3)

Answer 2

Type of malaria

Common

Specific to humans

Question 3

Genetic resistance to malaria (3)

Answer 3

7% population have haemoglobin disorders

700 structural haemoglobin variants

Thalassaemias (defective or imbalanced globin production)

Question 4

What was the distribution like of thalassaemias?

Answer 4

It was also in the Mediterranean not just Africa so malaria was also in other countries.

Question 5

CRISPR gene (2)

Answer 5

Gene editing technology

Makes TB resistant cattle

Question 6

Inheritance and mechanisms of protection (3)

Answer 6

1 in 4 chance of being affected

Decrease your tolerance to oxidative stress in red blood cells

Decrease Cyto adherence

Question 7

Duffy antigen (3)

Answer 7

Glycoprotein expressed in red blood cells that bind to chemokines it is the receptor for invasion.

2 major co-dominant alleles FYA and FYB (produce antigens FYa and FYb)

Some people have nucleotide polymorphism in FYB allele.

Question 8

What is the Duffy negative antigen

Answer 8

Where they have recessive alleles so malaria can’t invade

Question 9

Where is getting bad for malaria?

Answer 9

Madagascar as people also have Duffy positive to counteract the effect

Question 10

Life cycle of plague (6)

Answer 10

Woodland
Fleas
Rodents
Bite big animals
Cough etc on humans
Humans get plague

Question 11

Genetic footprint of Black Death (3)

Answer 11

Rroma people migrated out of north india to Europe

1/2 European population was wiped out

Rroma and Europeans have Toll-like receptors (tlr) which are essential for recognising bacteria

Question 12

Genetic resistance to TB (4)

Answer 12

Cystic fibrosis

• 2% of population In Europe
• mutation in CF transmembrane conductance regulator gene
• linked to decrease in host enzyme exploited by TB
• thus have a heterozygous advantage in CF

Question 13

Resistance in animals: a natural experiment in rabbits

Answer 13

Benign tumours inky in natural host but virulent in European rabbits

Host is resistant so fatality decreases

Question 14

Disease resistance in livestock (3)

Answer 14

Due to pesticides and vaccines

Can cause pathogens to be resistant

Not affordable in developing countries

Question 15

Limit of vaccines (3)

Answer 15

Expensive

Stalked

Needs research

Question 16

Bovine resistance to ticks (2)

Answer 16

Indicine (short hair and light hide from Asia) breeds more resistance than taurine (European)

Important vectors Of livestock diseases

Question 17

Trypanosomiasis (2)

Answer 17

Protozoan parasites (sleeping sickness)

Some transmitted by blood