Malaria Flashcards
What are the 5 pathogenic species of Malaria?
P. falciparum P. vivid P. oval P. malaria P. knowlesi
Out of the 5, which are the major cause of malaria in Malaysia?
P. knowlesi, followed by P. falciparum
Out of the 5, which are the most serious / deadly form of Malaria?
P. falciparum, followed by P. knowlesi
Out of the 5, which has the shortest incubation period?
P. falciparum (7-30 days)
Out of the 5, which has the longest incubation period?
P. malaria
What does the ‘P.’ stand for?
Plasmodium
e.g. P. falciparum - Plasmodium falciparum
What is the vector of Malaria?
female Anopheles mosquito
Why is there a rise in worldwide concern over the spread of Malaria?
- an increase in drug-resistant forms of Plasmodium
- increase in number of epidemics due to climate changes that favour the spread of mosquitoes
- migration of people from areas where malaria is endemic
What is Blackwater fever?
caused by P. falciparum manifestation,
characterised by:
- intravascular hemolysis
- hemoglobinuria (black urine)
- acute renal failure
How is Malaria transmitted?
- transmitted during infective stages into an uninfected person through the female Anopheles mosquito
- during blood transfusion
- reusing unsterilised needles
- across the placenta from mother to foetus
Where does the sexual stage of Malaria occur in?
In mosquitoes.
- mosquito take up gametocyte of pathogen when it bites an infected person
- male and female gametes fuse in mosquito’s gut and develop to form infective stage known as sporozoites
- sporozoites move to the mosquito’s salivary glands
Where does the asexual stage of Malaria occur in?
In humans.
- mosquito bites an uninfected person, sporozoites are injected into the person’s blood with the saliva
- parasites enter the liver cells and multiply - forming merozoites
- merozoites invade blood cells and liver cells
- some merozoites develop into male and female gametocytes and remain in blood until taken up by another mosquito
Re-infection of Malaria / why can malaria be very serious in places where it isn’t epidemic?
- people who are continuously re-infected by diff strains of malaria becomes immune
- only happens in they survive the first 5 years of life
- immunity only lasts as long as people are in contact with the disease
Who are resistant to malaria infection?
- sickle cell traits
- thalassemia
- glucose-6-phosphate-dehydrogenase deficiency
Explain the effects on body in the presence of Malarial parasites in the RBCs.
- malarial parasites invade RBCs ➡️ causes rupture ➡️ less haemoglobin to bind to oxygen
- less oxygen is transported, patients experience anaemia, fatigue and tiredness
- plasmodium may exert toxins which can cause fever, nausea, shivering
Explain the cold stage of malaria.
- patient experience intense cold and shivering that lasts 15-60 minutes
What is the reason for the cold stage of malaria?
- merozoites invade into erythrocytes, multiply and cause haemolysis
- haemolysis release haemozoin, which causes shivering in patients
Explain the hot stage of malaria.
- patient feels intense heat lasting for 2-6 hours
- patient develops high fever, severe headache, nausea and vomiting
Explain the sweating stage of malaria.
- fever ends
- patient sweats profusely and feel fatigue
- patients tend to fall asleep during this time
What are the diagnosis methods of malaria?
- microscopic identification of parasite stages in blood film
- antibody detection (can detect past infections)
- rapid diagnostic tests (RDTS) - detects Ag derived from lysed cells using immunochromatographic methods
Treatment for malaria
antimalarial drugs (quinine and chloroquine)
they inhibit protein synthesis and prevents parasite spreading within the body
Why are the treatment no longer effective in certain areas?
there are strains of drug-resistant Plasmodium in places where antimalarial drugs have been used widely
thus, the drugs are no longer effective against the pathogen
What are the 3 main ways to control malaria?
- physical methods
- biological controls
- use of prophylactics (preventive drugs)
Describe some of the physical methods to control malaria.
kill insect vector and break transmission cycle.
- spread oil over surfaces ➡️ larvae and pupae can’t breath
- drain swamps (control breeding)
