Infectious Diseases

Malaria

A parasitic disease caused by Plasmodium - a genus of eukaryotic, single celled parasites. 

Transmission

Plasmodium parasites are transmitted by mosquitoes. The female Anopheles act as vectors. They transfer the parasite into an animal's blood when they feed on  them. 

Infection

They infect the liver cells (hepatocytes) and red blood cells (erythrocytes) and disrupt the blood supply to vital organs. 

• A mosquito feeds and injects immature Plasmodium parasites into host
• They travel to the host's liver where they infect hepatocytes
• They multiply
• The parasites mature and the hepatocytes burst, releasing it into the blood stream. 
• The mature parasites replicate in the erythrocytes and infect.
• A mosquito then feeds, taking up the parasite. 
• They reproduce in the mosquito and immature parasites are formed.

Preventing and treating

A vaccine cannot be produced because:

• It is exposed in the bloodstream for too short of an amount of time to recognise and destroy it. 
• There are four different species with different antigens.
• Different stages have different antigens 

Protection:

• Mosquito nets and insect repellent stop people being bitten.
• Pesticides can kill the mosquito carriers.
• Education

Tuberculosis

A lung disease caused by the bacterium Mycobacterium tuberculosis.

Transmission

TB spreads by droplet infection. It is much more widespread in areas where hygiene levels are poor and where people live in crowded conditions. 

Infection

The bacteria invade a type of white blood cell found in the lungs, where they can lay dormant for many years. When someone becomes infected, immune system cells build a wall around the bacteria in the lungs. This forms small hard lumps known as…