Lecture 19- Malaria Flashcards
Nearly every minute a child under ____ dies of malaria
Child under 5
Malaria stands for?
Bad air
How long has P. falciparum been in existence for?
50,000 to 100,000 years
Malaria is ____ and ____ parasitic infection in history
- Serious
- Fatal
Who observed parasite inside RBC in 1880?
Charles Louis Alphonse Laveran
Malaria is a ____ born disease
Mosquito borne disease
Malaria is transmitted by what species?
Female anopheles group
What is the genus of malaria?
Plasmodium
What are the 5 human infection species of plasmodium?
- P. falciparum
- P. malariae
- P. ovale
- P. vivax
- P. knowlesi
What is the most severe form of malaria?
P. falciparum
P. knowlesi is restricted to ____ and is a ____ disease
- Southeast Asia
- Zoonotic disease (found in primates)
What were two 19th century drugs used to treat malaria?
- Quinine (fever tree bark)
- Artemisinins (extract from qinghao)
Was there malaria in the Rideau Canal/Eastern Seaboard and why?
- Yes
- Because the vector anopheles existed
- There was also long cycle (the ones that survived harsh winter in humans) and the short cycle (spread by mosquitoes)
- P. vivax so people were able to overcome infection
What species of malaria has been in the US?
- P. vivax
- P. falciparum
Has malaria come back into the US?
- Yes
- Seen cases that arent releated to travel
- Locally aquired cases in Texas and Florida
How many individuals are at risk of malaria in 90 endemic countries?
2 billion (125 million is travelers)
Huge amounts of cases is restricted to ____ with high amounts of deaths
Africa
What is the top infection in travelers with fever in Canada?
Malaria
What are the two most common strains of malaria seen?
- P. falciparum
- P. vivax
Where do you find P. falciparum?
- Sub Saharan Africa
- New guinea
- Central and South America
- Southeast Asia
- Tropics and subtropics
Where do you find P. vivax?
- Central and South America
- India
- Southeast Asia
- Eastern Africa
Describe the lifecycle of malaria
- Mosquito will take a blood draw, mosquito contains all these sporozoites
- It releases these sporozoites and has now entered the blood stream
- Once in the blood, they will locate themselves to the liver
- Once they infect a hepatocyte, the sporozoites will develop and mature into Schizonts
- It’ll enter the blood
- Then it’ll develop into the adult stages (trophozoite to mature trophozoite)
- Then to gametocyte that is picked up by the mosquito and turned back into sporozoites
What is a Schizont?
Its a large cell that contains thousands and thousands of daughter cells (merozoites)
What is a merozoite?
Young parasite that will eventually enter the blood stream
What are the two main stages of an infection?
- Liver stage
- Erythrocytic stage
It only causes infection when its in?
The blood (fever means its circulating in the blood)
What are the different stages in malaria life cycle?
- Sporozoite
- Schizont which contains merozoites
- Merozoites develop into trophozoites
- Can differentiate into schizont or gametocytes
- Gametocytes differentiates into a sporozoite in the mosquito
What are some general symptoms of malaria?
Fever, diarrhea, headache, sweats or chills, nausea or vomiting, muscle and stomach pain
What are some severe manifestations of malaria?
- Cerebral malaria
- Severe anemia
- Coma and death
Severe manifestations are most common in?
Children under the age of 5
Why do you need to differentiate the difference between severe (complicated) and non-severe (uncomplicated) malaria?
Do this because there are different treatment regiments based on what kind of malaria an individual has
What is non severe/uncomplicated malaria?
Symptomatic malaria without evidence of severe disease or vital organ dysfunction (general symptoms)
What is severe/complicated malaria?
- General symptoms plus severe manifestations
- Symptomatic malaria with this complications:
What is the most morbid complication of malaria?
Cerebral malaria
If cerebral malaria is untreated, the mortality rate is?
15-20% of cases
What are some symptoms of cerebral malaria?
- Confusion
- Disorientation
- Delirium
- Agitation
- Seizure activity -> coma > 30 min
How does cerebral malaria happen?
What happens to the brain in cerebral malaria?
Cortical thickening
What is considered the gold standard for malaria diagnostics?
Microscopy
What is the use of microscopy in the diagnosis of malaria?
Looking for the parasites in the blood and looking for the stage of the lifecycle
Why is microscopy limited in Canada?
- Limited accessibility because you need trained staff that can identify the different stages and differentiate the type of species and it takes a long time to develop this skill
- Not many cases in Canada, so harder to maintain this level of expertise
What is the difference between a thick and thin blood smear?
- Thick = allows you to look at the entire area to see if you can see anything abnormal
- Thin = to speciate and identify the stage in lifecycle
Why is microscopy considered a gold standard?
- Doesn’t take lots of money or resources
- People in endemic areas have lots of expertise for identifying different species
If you see a banana shaped gametocyte, then what species is it?
P. falciparum
The shape, size and number of ____ can differ between species
Merozoites and schizonts
What other parasite presents similarly to malaria under the microscope?
Babesia
What is an example of a Rapid Antigen Test (RAT) for malaria?
Immunochromatographic test = BinaxNOW malaria
What is T1 and T2 targets for RATs?
- T1 = targets histidine rich protein 2 (HRP2) specific for P. falciparum
- T2 = targets pan-malarial antigen common to all other malaria species (pan-aldolase)
What happens if you have a T1 band present on a RAT?
Most likely infection with P. falciparum
What is the main issue to RATs?
- Has undergone mutation to HRP2 (T1 target) to cause it to not show up as positive
- Can miss malaria all together without microscopy
Why can you not rely solely on one test?
You could miss the HRP2/3 mutant
Can you speciate using PCR?
Yes
Describe LAMP
- Loop-mediated isothermal amplification (LAMP)
- Uses 4-6 primers targeting 6-8 regions of DNA for highly specific amplification at a constant temperature
- Strand displacing DNA polymerase allows primers to bind to create loop structures that facilitate subsequent rounds of amplification of the loops and additional annealing of primers
- Product visualization by eye
- Compatible with real time fluorescence, lateral flow or agarose gel
____ is fast but no speciation available
LAMP
Which test is best when it comes to sensitivity?
Molecular assay
Which species are considered the relapsing species of malaria?
- P. vivax
- P. ovale
- Lays dormant in the liver
You need drugs to treat both what?
- Targets the parasites in the liver
- Targets parasites in the blood
What is the greatest threat to malaria control?
Drug resistance
What species have confirmed resistance?
- P. vivax
- P. falciparum
What are the two types of control initiatives?
- Fungus to kill anopholes mosquitoes
- Vaccine
What is malaria elimination?
Interruption of local transmission of a specified malaria parasite in a defined geographical area as a result of deliberate activities
