Antimalarials Flashcards
LO
identify the key events in the life cycle of the malaria parasite and how these may be affected by antimalarial agents
Topics covered
- The prevalence/ vector / parasite / disease / diagnosis/ susceptibility
- Parasite life cycle
- Vector control (including larvicides, insecticides, genetics)
- Vaccine
- Drugs for prophylaxis, acute treatment, and radical cure
- Resistance and future therapies/targets
What is malaria?
RBC are invaded by the Plasmodium species which is carried by mosquitoes
Its eukaryotic, parasitic protozoan
Infection by mosquito vector (and mother-foetus)
Where is the term ‘malaria’ from and what is also sometimes referred to as?
Literally bad air (from Old Italian “mal” ‘aria”)
Sometimes known as “intermittent fever” / “marsh fever”
When were cases of Malaria first recorded?
Recorded as far back as 3000 BC in China, India, and Egypt / Roman times in the UK (parasite in humans ~100,000 years)
Why do the number of UK cases rise?
Number of UK cases on the rise due to global travel (~2,000 a year – ‘suitcase’ malaria)
Also climate change
Malaria is described as being one of the ‘big three’ diseases, alongside what two others?
HIV
TB
in 2019, what were the reported cases and deaths of malaria by the WHO
Who was it more prevelant in and why?
229 million cases a year / 409,000 deaths (WHO 2019)
Found mostly children <5 because they have not been exposed to it and have no defences against it
What are the regions in which malaria is endemic?
endemic: when a diseases is generally found among certain populations and places
Primarily in tropical and subtropical regions as that is where the mosquitoes are present

Tell me about the stats for the Morbidity and mortality in sub-saharan Africa where its mainly concentrated
Morbidity: The state of having a specific illness or condition
Mortality: Refers to the nunber of deaths that have occurred due to a specific illness or condition
Under 5s account for 52% of deaths (2/3rds for under 14s)
Sub-Saharan Africa: 94% cases and 95% of deaths
The global cases are falling but, successes in this since the 2000 are slowing due to what factors?
‘Success’ – sustainability/removal of funds
Resistance (mosquito and Plasmodium)

How is malaria transmitted?
Transmitted through the “bite” of the female mosquito genus Anopheles (~40 species associated with malaria)
What happens when a mosquito bites its target?
Parasite initially ingested during a blood meal of an infected individual, it grows replicates in gut, and is then passed on during subsequent meal (8-15 sporozoites)
Sporozoites: a motile spore-like stage in the life cycle of some parasitic sporozoans (e.g. the malaria organism), that is typically the infective agent introduced into a host.
Where are mosquitos usually found?
Abundant and distributed all over the globe, including the Arctic, but particularly widespread in tropical / sub-tropical regions, particularly around stagnant water (as larvae grow in stagnant water. Issue in places like Africa who will have large rainfalls and large water pools forming so trying to target this is quite difficult)
How can the parasites be transmitted/
Parasites can be transmitted through blood transfusions and contaminated needles (but generally rare), as well as intra-uterine (mother-baby); can lead to complications and potentially miscarriage
What are the 5 species of parasite that can form malaria and rank them from most to least dangerous
Which ones require radical cure and why?
P. falciparum (most serious / 90% deaths)
P. vivax*, ovale*, malariae (milder disease)
P. knowlesi (zoonotic - monkey & human)
*Requires radical cure- because they have a dormant state in the liver which can hide from the immune system and then erupt and come back later in life
How does the parasite uptake the nutrients it requires from the red blood cells?
Uptake material from RBC; haemoglobin and protein component. Has a food vacuole

Explain abit about the incubation period of the different malarial parasites
Can live in system for a few weeks without any symptoms. Only when its present in your blood is its known that you are infected

Tell me what the initial symptoms are for the malarial parasites
- flu like
- headache
- Photophobia
- muscle aches
- nausea
- vomiting
- chills (10-15 mins)
- Fells cold but is actually feverish
- Jaundice
Jaundice as RBC breaking down and bilirubin being present

Tell me about the periodicity of the malarial parasites
Goes through rounds of replications once in RBC leading to cycles of symptoms- periodicity

Tell me about the onset of diseases the the severity and duration (hr) for malarial parasites
Can cross BBB, clump RBC and this can lead to blocking blood vessels and brain swelling which leads to death- if survive it can lead to chronic conditions

With the malarial parasite if left untreated or not treated properly it can lead to relapses or recrudescences, explain this
If untreated by drugs, then it can come back during your lifetime
Recrudescence is when you haven’t fully cleared from blood, not completely killed, will come back
Why can one get anaemia from malarial parasites?
Anaemia as breaking over blood cells and have the side effects from this
The disease and the 5 malarial parasites




























