Malaria Flashcards
What is the pre-erythrocytic development stage of malaria?
The development of the malaria parasite when it first enters the host (liver stage) after inoculation by a female anopheles, invading hepatocytes and multiplying for 5-12 days.
Define radical cure in the context of malaria.
Refers to both cure of blood-stage infection and prevention of relapses by clearing hypnozoites (P. vivax and P. ovale infections only).
What is recrudescence in malaria?
Recurrence of asexual parasitaemia following antimalarial treatment comprising the same genotype(s) that caused the original illness.
Differentiate between recrudescence and reinfection.
Recrudescence results from residual asexual parasitaemia due to inadequate treatment, while reinfection is a new malaria infection shortly after treatment.
What causes relapse in P. vivax and P. ovale malaria?
Recurrence of asexual parasitaemia deriving from persisting liver stages (hypnozoites) after the blood-stage infection has been eliminated.
How do malaria parasites exhibit their lifecycle?
They have a complex lifecycle in both human and mosquito hosts, with asexual stages occurring in humans and sexual stages occurring in mosquitoes.
What are the clinical symptoms of malaria associated with?
Erythrocytic invasion, growth and division, followed by cell lysis and re-invasion.
What is the gold standard for parasitological diagnosis of malaria?
Light microscopy, specifically examining a Giemsa stained thick or thin blood smear.
What is an mRDT?
Malaria Rapid Diagnostic Test; a device that detects parasite-specific antigens or enzymes.
What are the limitations of microscopy in malaria diagnosis?
Lack of expert microscopists, constant electricity, infrastructure, and quality reagents.
What does PCR stand for in malaria diagnosis?
Polymerase chain reaction, a method that amplifies genus- and species-specific sequences of the parasite.
List some control measures for malaria management.
- Use of long-lasting insecticidal nets (LLINs) * Indoor residual spraying (IRS) * Clearing mosquito breeding areas * Seasonal screening and mass drug administration * Chemoprophylaxis and chemotherapy * Improve childhood nutrition
What are tissue schizontocidal drugs?
Causal drugs that eliminate liver stage from initiating erythrocytic stage.
What is the primary action of blood schizontocidal drugs?
They act quickly on erythrocytic stages, with examples being artemisinin and quinolines.
What are gametocytocidal drugs used for?
They destroy sexual erythrocytes, preventing transmission to mosquitoes.
What is the mechanism of action for quinoline drugs?
Inhibits heme crystallization.
What is the role of artemisinin in malaria treatment?
Rapidly effective against malaria parasites, radically reducing parasite counts.
What is artemisinin combination therapy (ACT)?
Combines an artemisinin derivative with a partner drug for treating uncomplicated P. falciparum malaria.
What are the common side effects of artemisinin derivatives?
- Nausea * Vomiting * Diarrhea * Dizziness
What is the recommended treatment for uncomplicated P. falciparum malaria?
Artemisinin-based combination therapies (ACTs) such as Artemether + lumefantrine.
What should be done for severe malaria treatment?
Use intravenous or intramuscular artesunate for at least 24 hours, followed by oral treatment with ACT.
What is the pharmacokinetics of artemisinin?
Half-life of 1-3 hours.
What are some examples of artemisinin derivatives?
- Artemether * Artesunate * Dihydroartemisinin
What is the rationale behind using ACTs?
To rapidly kill > 95% of the parasite and reduce the chances of resistance.
What should be avoided in treating HIV co-infected patients with malaria?
Avoid certain combinations of treatments like artesunate + SP when patients are receiving co-trimoxazole.
What is the typical duration for taking artemisinin?
7 days with a half-life of about 3 hours
What is the current standard regimen duration for combination therapy with artemisinin?
3 days
List the first-line approved ACT.
Artemether + lumefantrine (AL)
List the second-line approved ACT.
Artesunate + amodiaquine (AA)
Which drug is combined with long-acting sulfonamides?
Pyrimethamine
What stages of malaria does pyrimethamine inhibit?
All stages except late-stage gametocytes and hypnozoites
What is the half-life of sulfadoxine?
100-230 hours
What is the combination of sulfadoxine and pyrimethamine known as?
Fansidar
What adverse reaction can occur with sulfadoxine?
Stevens-Johnson syndrome
What is chemoprevention in the context of malaria?
Use of antimalarial medicines for prophylaxis and preventive treatment
Who are considered at-risk groups for malaria?
Pregnant women, infants and children under 5, people with HIV/AIDS, immunocompromised individuals, non-immune travelers, and individuals returning from malaria endemic countries
What does SMC stand for in malaria prevention?
Seasonal Malaria Chemoprophylaxis
What is the purpose of causal prophylaxis?
Prevents the establishment of infection in the liver
Fill in the blank: Atovaquone + _______ is effective as a causal prophylactic drug.
proguanil
What is the recommended treatment for pregnant women according to WHO?
IPTp with sulfadoxine-pyrimethamine
What is the causative agent of malaria?
Plasmodium (unicellular protozoan)
How many cases and deaths from malaria were reported globally in 2022?
249M cases & 608,000 deaths
What are the five main species of Plasmodium pathogenic to humans?
- P. falciparum
- P. malariae
- P. vivax
- P. ovale
- P. knowlesi
Which species of Plasmodium is most virulent?
P. falciparum
What is suppressive prophylaxis?
Use of blood schizonticides to protect against clinical illness
What are some antimalarials used for chemoprophylaxis?
- Atovaquone + Proguanil (Malarone)
- Chloroquine
- Proguanil
- Doxycycline
- Mefloquine
- Primaquine
What is antimalarial drug resistance?
Ability of a parasite strain to survive and multiply despite adequate drug administration
What is the trade name of the pre-erythrocytic stage vaccine approved in 2015?
Mosquirix
What defines severe malaria?
Presence of one or more severe symptoms such as coma, metabolic acidosis, or severe anemia
What is cerebral malaria?
Unarousable coma associated with proven P. falciparum infection
What are common symptoms of malaria?
- Headache
- Fatigue
- Fever
- Chills
- Vomiting
Which population is most vulnerable to malaria deaths?
Children under five years of age
What is the asexual cycle in malaria?
Life cycle from merozoite invasion of red blood cells to schizont rupture
Fill in the blank: The presence of asexual parasites in the blood without symptoms is known as _______.
asymptomatic parasitaemia
