Transmission of diseases AS Biology Unit 2 OCR

In order to cause disease a pathogen must

• Travel from one host to another
• Get into hosts's tissues
• Reproduce
• Cause damage to host's tissues

Most common forms of transmission
Means of vector
Physical contact
Droplet infection

Transmission Of Malaria

Malaria is spread by a vector

• The host has malaria, a mosquito will sucj the parasite gametes into its stomach
• the gametes fuse and the zygotes develop in the mosquitos stomach
• Infective stages are formed and these move to the mosquitos salivary glands
• When the mosquito bites someone, it uses it's saliva as an anticoagulant os it can drink the blood
• This saliva conatains the infective stage of the parasite
• In the human host, the infective stage enters the liver and multiplies before…