Malaria is still a big challenge to the world’s health status, especially in tropical and subtropical areas, as Plasmodium parasites that cause this possibly fatal disease have been passed through the infected Anopheles mosquito’s bite. The good news is there are prevention measures available to address this issue. This article will explain mechanisms, types, and how different types of antimalarial drugs were used for the prevention of the disease.
Understanding Malaria
What is Malaria?
Malaria is a parasitic infection caused by the Plasmodium species, which includes:
- Plasmodium falciparum: The most severe form, often leading to life-threatening complications.
- Plasmodium vivax: Known for causing relapses due to its dormant liver stage.
- Plasmodium ovale: Similar to P. vivax, it can cause relapses.
- Plasmodium malariae: Typically causes a mild form of malaria.
- Plasmodium knowlesi: Primarily affects macaque monkeys but can infect humans and cause severe disease.
Transmission and Symptoms
Malaria is a human infection that is carried by mosquitoes. A mosquito requires a blood meal before she can lay her eggs; she gets this blood meal by biting a human or another animal. Anopheles mosquitoes carry the parasite, Plasmodium. Each day, more than 1,000 people die from malaria. Symptoms appear an average of 10 to 15 days after being bitten by an infected mosquito. Symptoms usually include:
- Fever
- Chills
- Headache
- Nausea and vomiting
- Muscle pain and fatigue
If left untreated, the disease can progress to cause anemia, respiratory distress, and cerebral malaria – which is fatal.
Antimalarial Drugs for Prevention
Purpose of Antimalarial Drugs
Antimalarial drugs can be used both to prevent malaria infection (particularly for those traveling to endemic areas and those at high risk) and as part of an acute treatment regime. Examples include:
- Killing Plasmodium Parasites: Preventing the parasites from growing and multiplying.
- Inhibiting Parasite Lifecycle: Preventing the parasites from reaching/maturing in the liver or red blood cells.
- Reducing Mosquito Transmission: Minimizing the likelihood of transmission to mosquitoes if infection occurs.
Types of Antimalarial Drugs
Prophylactic Medications
(Antimalarials are taken before exposure and during travel to prevent malaria.) Prophylactic antimalarial drugs include:
- Chloroquine: active against P vivax and P malariae, but not as useful against P falciparum; often used in combination with other drugs.
- Mefloquine: active against all Plasmodium species, particularly useful to travelers and in settings where chloroquine-resistant malaria is found.
- Doxycycline: A ‘blood’ schizonticidal antibiotic used as a second-line option when other drugs are not suitable.
- Atovaquone-proguanil: A combo drug (sold under brand names such as Malarone) that works against every Plasmodium species including drug-resistant strains, and is the drug of choice for short-term travelers.
- Primaquine: Kills the liver stages (hypnozoites) of P vivax and P ovale, eliminating them from the liver to prevent relapse.
Emergency Treatment
On average, there are three or four drugs available to them If they do go on to develop malaria, despite having taken prophylaxis, then they’ll have to be treated with one of various kinds of therapeutic antimalarial drugs:
- Artemisinin-based Combination Therapies (ACTs): Artemisinin derivatives, composed of one or more other antimalarial compounds, are the primary treatment for uncomplicated P falciparum malaria.
- Quinine-Based Therapies: Used for severe malaria or when ACTs are not available.
Choosing the Right Medication
Selecting the appropriate antimalarial drug depends on several factors:
- Travel Destination: The type of malaria prevalent in the area (e.g., chloroquine-resistant P. falciparum).
- Health Conditions: Pre-existing medical conditions and potential drug interactions.
- Duration of Stay: Some drugs are better suited for short-term versus long-term use.
- Personal Tolerance: Side effects and individual tolerance of the medication.
Considerations and Side Effects
Effectiveness and Resistance
Drug resistance: Resistance, especially to chloroquine and artesunate, has become a big problem, and both surveillance and the modification of treatment guidelines are required.
Efficacy: Making sure the chosen prophylactic drug is effective against the local strain of malaria.
Side Effects
Antimalarial drugs can have side effects, which vary depending on the drug:
- Chloroquine: May cause nausea, headache, and visual disturbances.
- Mefloquine: Can lead to dizziness, vivid dreams, and, in rare cases, neuropsychiatric effects.
- Doxycycline: Common side effects include gastrointestinal disturbances and photosensitivity.
- Atovaquone-proguanil: Typically well-tolerated but may cause gastrointestinal symptoms and headache.
- Primaquine: Can cause hemolysis in individuals with glucose-6-phosphate dehydrogenase (G6PD) deficiency.
Adherence to Medication
Adherence to the prescribed regimen is vital for effectiveness. Strategies to enhance adherence include:
- Education: Providing clear instructions and information about the importance of completing the medication course.
- Reminders: Use tools like pill organizers or mobile apps to track medication schedules.
Future Directions
Advances in Antimalarial Research
Ongoing research aims to improve antimalarial drugs and strategies:
- New-Drug Development. New drug research programs that target resistant pathogens and have fewer side effects.
- Vaccines: Efforts are underway to develop vaccines that provide long-lasting protection against malaria.
- Combination Therapies: Exploring new combinations of existing drugs to enhance efficacy and prevent resistance.
Global Efforts
Global initiatives and collaborations are working to reduce malaria incidence through:
- Enhanced Surveillance: Improving tracking and monitoring of malaria cases and drug resistance.
- Integrated Control Programmes: The combination of antimalarial drugs and vector control measures, including the distribution of insecticide-treated bed nets and indoor spraying techniques.
- Access to Medications: Ensuring that antimalarial drugs are accessible and affordable in endemic regions.
Although antimalarial drugs cannot eliminate the parasite from infected individuals, they can prevent it from spreading, thus halting transmission. An important goal, especially in high-transmission zones, is to stop people from getting sick with malaria. By understanding the types of prophylactic drugs and their strengths and weaknesses, people and their physicians can make decisions on their use or the default use for travelers. Research and new interventions continue in the battle for malaria prevention and cure. The WHO and many different organizations are working every day to make accessible better, easier, and more effective prophylactic and treatment methods. With them, we can pray to one day live in a malaria-free world.
