Chapter 10 Infectious Diseases

Question 1

Cholera pathogen

Answer 1

Vibrio cholerae

Question 2

Malaria pathogen

Answer 2

Four species of plasmodium

Question 3

AIDS pathogen

Answer 3

HIV

Question 4

Tuberculosis

Answer 4

Mycobacterium tuberculosis and M. bovis

Question 5

Measles pathogen

Answer 5

Morbillivirus

Question 6

Smallpox pathogen

Answer 6

Variola virus

Question 7

Cholera transmission

Answer 7

• Water borne
• Food borne, if infected people don’t wash their hands
• Transmitted by diarrhoea and faecal matter

Question 8

Malaria transmission

Answer 8

Insect vector: female mosquito. The plasmodium replicates both in the mosquito and in the human.
Also can be spread in blood transfusion and when unsterile needles are used. Can also travel from mother to foetus through the placenta.

Question 9

AIDS transmission

Answer 9

In semen and vaginal fluids, infected blood, contaminated syringes, placenta, birth, breast milk.
Initially transferred throughout the male homosexual population, who often had multiple sexual partners and practised anal sex.

Question 10

TB transmission

Answer 10

Airborne droplets, for M.bovis uncooked meat and unpasteurised milk.

When infected people cough or sneeze, the little droplets contain the bacterium. It spreads therefore most in crowded areas, or places where people sleep close together. AIDS also makes people susceptible to TB.

Question 11

Measles transmission

Answer 11

Through coughs and sneezes many droplets containing the virus enter the air. Very contagious, if people inhale these droplets, it is almost definite they will be infected

Question 12

Prevention and treatment of Cholera

Answer 12

Can be treated with intravenous or oral rehydration therapy.
Is prevented by providing clean, chlorinated water and good sanitation, ensuring no infected faeces contaminates the water supply.

Developing countries can often have large cities with inadequate sewage infrastructure, this promotes the spread of cholera.

There are often cholera outbreaks after natural disasters.

Question 13

Prevention and treatment of Malaria

Answer 13

Reducing the number of mosquitoes through insecticide or draining swamps or oiling the surfaces, mosquito nets and other preventative measures, and using drugs to prevent infection.
Other drugs like chloroquinine help those infected, by inhibiting protein synthesis.

Question 14

Prevention and treatment of HIV

Answer 14

Barrier methods, education to practise safer sex, contact tracing.
There are expensive drugs that can be taken to interfere with the replication of HIV.
Anyone who is infected is discouraged from donating blood.

Question 15

Treatment and prevention of TB

Answer 15

Several drugs are used to ensure all of the bacterium are killed, leaving no resistant bacteria behind. The full course must be completed.

Contact tracing is used. There is also a vaccine which’s effectiveness declines with age. Pasteurised milk cannot transmit TB

Question 16

Treatment and prevention of Measles

Answer 16

Treatment is bed rest and medicines for the fever - it usually goes away after around 10 days.

The introduction of a vaccine made its prevalence in developed countries very low. In developing countries however, where people live in crowded areas and many children are malnourished it is very prevalent.

Question 17

Global patterns of malaria

Answer 17

Malaria is more deadly in countries where it is seasonal, as immunity is not long lasting. It is often in the rainy seasons, which is also when agriculture is most active, which is very problematic for the economy.

Mainly in the tropics.

The WHO attempted a global eradication of malaria, which was mainly unsuccessful, as plasmodium became resistant to the drugs, mosquitoes became resistant to the insecticides.
In addition, people were even more susceptible to malaria after it had been removed from their area. The insecticide also increased the number if caterpillars which ate people’s roofs in SE Asia

Question 18

Global patterns of AIDS

Answer 18

Worldwide, especially sub-Saharan Africa and SE Asia. The initial epidemic was in Europe and NA, and later a greater pandemic occurred in Africa. AIDS has an adverse effect on developing countries as the sexually active people are also the most economically active.
Testing specific groups is also not possible in these nations as HIV is so widely spread.

Question 19

Global patterns of TB

Answer 19

Worldwide. Infections from M.bovis are very few in developed countries due to controls put in place, but developing countries may not have such controls.
TB is present in some countries because of resistant strains, yhe AIDS pandemic, poor housing.