Types of communicable diseases

How measles spreads

How measles spreads

By droplets from an infected person’s sneeze or cough

Symptoms of measles

• Red skin rash

• Signs of fever eg. high temperature

Complications of measles

Can be fatal if it leads to pneumonia (a lung infection) or even brain infections

Preventing measles

Most people are vaccinated against the disease when they are young

Viral diseases

• Measles

• HIV

• Tobacco Mosaic Virus (TMV)

Symptoms of TMV

• Causes a mosaic pattern on leaves of the plant

• Parts become discoloured

Results of TMV

Discolourations means photosynthesis is carried out at a lower rate, so growth is stunted

How HIV spreads

• Spread by sexual contact or exchanging bodily fluids

• When people share needles blood may be shared

Symptoms of HIV

Causes flu-like symptoms for a few weeks, and then none for a few years.

How to control HIV

Antiretroviral drugs prevent the virus from replicating inside body cells

Results of HIV

The virus attacks the immune cells and bad damage means that it can’t cope with other infections or cancers. At this stage, the virus is known as AIDS.

Fungal disease

Rose Black Spot

Symptoms of Rose Black Spot

• Purple of black spots develop on leaves

• Leaves may turn yellow and drop off

Results of Rose Black Spot

Less photosynthesis happens (as a result of the black/purple discolouration of leaves) so the plant cannot grow well.

How Rose Black Spot spreads

In water or by the wind

Treatments for Rose Black Spot

Farmers use fungicides or strip the plant of its affected leaves. These need to be destroyed so the fungus doesn’t spread to other rose plants.

Protist disease

Malaria

How Malaria spreads

Mosquitoes are vectors which pick up the protist when they feed on an infected animal.
When the mosquito feeds on another animal, it infects it by inserting the protist into the animal’s blood vessels.

Symptoms of Malaria

• Repeating episodes of fever

• Death

Protecting against Malaria

People can use insecticides and mosquito nets.

Bacterial diseases

• Salmonella

• Gonorrhea

Symptoms of Salmonella

• Fever

• Stomach cramps

• Vomiting

• Diarrhoea

(These symptoms are caused by the toxins produced by the bacteria)

How you get Salmonella

• Eating food which has been contaminated with the Salmonella bacteria while alive (eg. chicken which caught the disease)

• Eating food which has been contaminated by by being prepared in unhygienic conditions

How Gonorrhoea spreads