viral diseases

• viral disease include: measles, HIV and TMV
• measles is spread by droplets from an infected person's sneeze or cough
• people with measles develop a red skin rash and they show signs of fever
• measles can be very serious, or even fatal, if there are complications
• measles can sometimes lead to pneumonia or a brain infection called encephalitis
• most people are vaccinated against measles when they are young
• HIV is a virus spread by sexual contact, or exchanging bodily fluids such as blood - sharing needles when taking drugs
• HIV initially causes flu-like symptoms for a few weeks - usually the person doesn't then experience any symptoms for several years
• HIV can be controlled with antiretroviral drugs - these stop the virus from replicating
• the virus attacks the immune cells - this is what makes you feel ill as your immune system is unable to fight other infections or cancers, as it is badly damaged
• when the immune system is so badly damaged the virus is known as HIV or AIDS
• tobacco mosaic virus (TMV) is a virus that affects many species of plants
• TMV cause a mosaic pattern on the leaves of the plants - parts of the leaves become discoloured
• the discolouration on the leaves means the plant can't carry out photosynthesis as well as before, so the virus affects growth
• to prevent the spread of TMV: farmers would burn the infected leaves
• there is no treatment for TMV
• TMV is spread by infected leaves rubbing against healthy leaves