| what is malaria | eukaryotic parasite (pathogen), affecting the liver, red blood cells and brain, causing anaemia and sivering and sweating |
| what is malaria caused by | by parasites of the protoctist genus plasmodium. plasmodium falciparum is the most wide spread and dangerous. host in humans and mosquitoes (genus anopheles). anopheles mosquitoes that transfer a parasite to its main host are known as vectors |
| transmission of malaria | occurs when an infected person is bitten by a female anopheles mosquito. the insect is a vector as it is not harmed by the pathogen, when the female anopheles takes another blood meal, this time from an unifected people, plasmodium is injected into the person with an anticoagulant from the salivary gland. the antigoagulant prevetns the human blood from clotting and so allows the mosquito to suck the blood up. |
| where are mosquitoes (with malaria) confined | tropical climate provide the best breeding and living conditions for the anopheles mosquitoes
plasmmodium needs temprature in excess of 20 c to complete its life cycle within the mosquitoe
the life cycle requires areas of still water. |
| prevention and control of malaria 1 | control of mosquitoes
- draining marshes and other areas of water where the mosquitoes lay their eggs
- introducing fish which consume mosquito larvae
- spraying freshwater areas with a parasite that kills mosquito larvae
- spraying oil over freshwater areas to prevent the mosquito larvae breathing the air they need to survive. |
| prevention and control of malaria 2 | control by humans
-keeping doors and windows closed as far as possible
- using insect repellents on the skin
sleeping under insecticide treated beds nets to prevent the mosquito from reaching the human host
- sparying the walls and ceiling of homes with an insecticide. |
| prevention and control of malaria 3 | control of plasmodium
- protect those not yet affected, by takign preventative (prophylatic) drugs, such as chloroquine and tovaquone. |
| why is prevention of malaria proving difficult | poor education and a failure to follow preventative measures properly
wars and politcal unrest, preventing anti maralarial measures
migrants spreading the disease to unaffected areas
poverty in affected countries leaving few resources for medical treatements
insecticide resistant in mosquitoes
drug resistance in plasmodium |
| difficulties with developing a malarial vaccine. 1 | the RTS.S vaccine has now been approved for the malaria vaccine implementation programme (MVIP), this is a larg scale pilot programme where the vaccine is given to young children in selected areas of three african countries. it is shown that the vaccine only gives some protection against malaria. |
| the development of a vaccine against malaria has been very difficult | plasmodium is a eukoryotic organism and therefore has many genes, can code for a wide variety of surface antigens
many life cylce within humans, each one having different surface antigens
plasmodium also lives inside red blood cells and cells of the liver. surrounded by the membrane of the host cells, it does not cause an immune response from the lymphocytes of the body's immune systeem, equally any antibodies present in the blood cannot work against the stages of plasmodium that occur within cells. |
