Malaria Flashcards
What is the pathogen that causes malaria?
These are four species of plasmodium
Plasmodium falciparum
Plasmodium malariae
Plasmodium vivax
Plasmodium ovale
What is the main method of transmission?
Insect vector: female Anopheles mosquito (about 30 different species)
What is the global distribution of malaria?
Tropics and subtropics (endemic in 106 countries)
What is the incubation period?
From a week to a year
What is the site of action of the pathogen?
Liver, red blood cells, brain
What are the clinical features of malaria?
Fever, anaemia, nausea, headaches, muscle pain, shivering, sweating enlarged spleen
What is the method of diagnosis?
Dipstick chest for malaria antigens in blood microscopy examination of blood;
signet ring appearance
What was the annual incidence worldwide in 2017
219, million cases of malaria in 90 countries (WHOS estimate) 92% of cases are in Africa
What was the annual mortality rate worldwide in 2017?
435,000 deaths (WHO estimate) 93% of deaths were in Africa
What does the genetic analysis of the infection of malaria show that some species of plasmodium that cause malaria in monkeys also affect
Humans
What is a disease vector?
An organism which carries a pathogen from one person to another or from an animal to a human
What is a disease vector?
An organism which carries a pathogen from one person to another or from an animal to a human
What is the disease vector of malaria?
The female Anopheles mosquito and she transmits the disease when she passes the infective stages into an uninfected person
What is infected stage?
The stage during which the pathogen takes a form in which it can invade its host cell
Apart from mosquitoes, what are some other methods of transmission of malaria?
It can be transmitted
during blood transfusion
when unsterile needles are reused
The pathogen can also pass across the placenta from mother to fetus
Describe the process of transmission by female Anopheles mosquitoes
-Female Anopheles mosquito feed on human blood.
-If the person they bite is infected with Plasmodium, they will take some of the pathogen’s gametes with the blood meal
-male and female gametes fuse in the misquote’s gut and develop to form infective stages.
-the infective stages move to the mosquito’s salivary glands.
-when the mosquito feeds again she injects an anticoagulant from her salivary glands that prevents the blood meal from clotting so that it flows out of the host into her body.
-The infective stages passes from the mosquito’s salivary glands into the human’ blood together with the anticoagulant
-The parasites enter the red blood cells where they multiply
Why do the female Anopheles mosquitoes feed on human blood?
To obtain the protein they need to develop their eggs
When is the transmission of pathogens of malaria more intense?
When the mosquitoes have a longer lifespan so that the parasite has time to complete its development inside the mosquito
When it prefers to bite humans rather than other animals
Why are about 90% of malaria cases in the world are in Africa?
They have a long lifespan
They have strong human biting habit
Most of the cases in Africa are caused by which pathogen
Plasmodium falciparum
Which species causes the most severe and often fatal malaria
Plasmodium falciparum
Why is the transmission of malaria seasonal in some places?
Because transmission also depends on climatic conditions which affect the number and survival of mosquitoes. And many places the peak of transmission is during and just after the rainy season.
What are the climatic conditions that affect the number of transmission of malaria?
Rainfall patterns, temperature and humidity
What are the climatic conditions that affect the number of transmission of malaria?
Rainfall patterns, temperature and humidity
When can malaria epidemics occur?
When climate and other conditions suddenly favour transmission in areas where people have little or no immunity to malaria.
They can also occur when people with immunity move into areas with intense malaria transmission
If people are continually re infected by different strains of malaria, they become immune. However, this only happens if
They survive the first five years of life when mortality from malaria is very high