Malaria 101: Everything You Need to Know About This Mosquito-Borne Illness

Did you know malaria remains a significant health concern in India, especially during the monsoon season? Anopheles mosquito, the carrier of malaria, thrives in hot and humid weather, making monsoon a perfect climate for them to breed.

Generally, mosquito bites are not troublesome, but an infected anopheles mosquito bite can prove to be fatal. If you are curious about how to protect yourself this monsoon season, then keep on reading for a short guide on malaria.

What is Malaria?

Malaria is a potentially life-threatening disease caused by parasites of the Plasmodium species, which are transmitted to humans through the bites of infected female Anopheles mosquitoes. These mosquitoes thrive in warm, humid climates, which is why malaria cases often surge during rainy seasons in tropical and subtropical regions.

The disease is characterised by a range of symptoms that typically include fever, chills, headache, muscle aches, and fatigue. In severe cases, it can lead to complications such as anaemia, respiratory distress, cerebral malaria, and organ failure, which can be fatal if not treated promptly.

What are the Different Types of Malaria Parasites?

There are over 150 species of Plasmodium parasites, but only five of them can infect humans and cause malaria disease. Here's a breakdown of the five main types of malaria parasites:

• Plasmodium Falciparum: This species is the most deadly and prevalent cause of malaria, particularly in sub-Saharan Africa. It can lead to severe complications and is responsible for the majority of malaria-related deaths worldwide.
• Plasmodium Vivax: Although less deadly than P. falciparum, P. vivax is the most geographically widespread species, found in many regions of the world, including Asia, Latin America, and parts of Africa. It can cause relapses of malaria months or even years after the initial infection due to its ability to remain dormant in the liver.
• Plasmodium Malariae: This species typically causes a milder form of malaria and is found in many parts of the world, especially in Africa. Infections with P. malariae can persist for long periods, often without causing noticeable symptoms.
• Plasmodium Ovale: Similar to P. vivax, P. ovale can also cause relapses of malaria due to its ability to remain dormant in the liver. It is primarily found in West Africa and some parts of Asia and the Pacific.
• Plasmodium Knowlesi: This plasmodium parasite primarily infects macaque monkeys but can occasionally infect humans, particularly in Southeast Asia. Infections with P. knowlesi can cause severe malaria and have been increasingly reported in recent years.

Each of these malaria parasites has unique characteristics and geographic distributions, contributing to the complexity of malaria transmission and control efforts worldwide.

How does Malaria Spread?

Malaria has a specific cycle of transmission that involves both humans and mosquitoes:

• Mosquito Infection: The malaria life cycle starts with an infected female Anopheles mosquito. When this mosquito bites a person carrying malaria parasites in their blood, the parasites enter the mosquito's body.
• Parasite Development: Inside the mosquito, the malaria parasites undergo a complex development process over a period of about a week. They mature and multiply within the mosquito's gut.
• Human Infection: Once the development is complete, the mature parasites migrate to the mosquito's salivary glands. When the infected mosquito bites another person, these infective parasites are injected into the person's bloodstream through the mosquito's saliva.
• Liver Invasion: The injected malaria parasites travel through the bloodstream and reach the liver. Inside the liver, the parasites multiply further, hiding and maturing within liver cells.
• Red Blood Cell Infection: After a period of time (depending on the parasite species), the mature parasites break out of the liver cells and invade red blood cells. Here, they reproduce rapidly, causing the infected red blood cells to burst.
• Symptoms and Transmission: The bursting of red blood cells releases toxins and infected red blood cells into the bloodstream, leading to the characteristic symptoms of malaria like fever, chills, and fatigue. If another mosquito bites this infected person at this stage, the cycle starts again, perpetuating the spread of malaria.

What Causes Malaria?

Various species of Plasmodium parasites can cause malaria in humans, with Plasmodium falciparum being the most deadly. Transmission occurs when infected mosquitoes bite humans, injecting the parasites into the bloodstream. Environmental factors, mosquito behaviour, and human activities all influence the spread of malaria.

What are the Signs and Symptoms of Malaria?

Malaria presents with a range of signs and symptoms that typically develop within 7 to 30 days after being bitten by an infected mosquito. Common malaria symptoms include:

• Fever: Fever is often the first and most prominent symptom of malaria. It can be intermittent or continuous and may spike to high temperatures.
• Chills: Chills usually accompany fever and can be severe, leading to shaking or rigours.
• Headache: Headaches are common and can range from mild to severe.
• Muscle and Joint Pain: Patients may experience generalised body aches, including muscle and joint pain.
• Fatigue: Profound weakness and fatigue are common, often accompanied by a feeling of overall malaise.
• Nausea and Vomiting: Nausea and vomiting may occur, particularly in the early stages of the illness.
• Sweating: Profuse sweating, especially following a fever episode, is characteristic of malaria.
• Abdominal Pain: Some individuals may experience abdominal pain, diarrhoea, or other gastrointestinal symptoms.

In severe cases of malaria, additional symptoms and complications may arise, including:

• Severe Anaemia: A significant decrease in red blood cell count can lead to symptoms such as paleness, weakness, and shortness of breath.
• Respiratory Distress: Severe malaria can cause difficulty breathing due to fluid accumulation in the lungs.
• Cerebral Malaria: Infection of the brain with malaria parasites can lead to neurological symptoms, including confusion, seizures, and coma.
• Organ Failure: Severe malaria can result in dysfunction of vital organs such as the kidneys or liver, leading to complications that may be life-threatening.

How is Malaria Diagnosed?

Malaria diagnosis relies on detecting the presence of the Plasmodium parasite in a person's blood. Here's a breakdown of the most common methods:

• Blood Smear Microscopy: This is the gold standard for malaria diagnosis, especially in areas with limited resources. A thin and thick blood smear is prepared on a slide and examined under a microscope by a trained professional. The thin smear allows visualisation of infected red blood cells, while the thick smear concentrates the parasites for easier detection. This test can identify the specific Plasmodium species and estimate the parasite density in the blood.
• Rapid Diagnostic Tests (RDTs): These are quick and easy-to-use tests that can be performed at clinics or even in the field. RDTs use immunochromatographic technology to detect specific proteins from the Plasmodium parasite in a blood sample. They provide results within 15–30 minutes and are highly sensitive for P. falciparum, the most dangerous type. However, they might not be as effective for detecting other Plasmodium species and may not distinguish between different parasite species.
• Molecular Diagnostics (PCR): Polymerase Chain Reaction (PCR) tests are highly sensitive and specific for detecting malaria parasites. These tests can identify the parasite's DNA even in cases with low parasite density. However, PCR tests are more expensive and complex than blood smears or RDTs and require specialised equipment, limiting their availability in some settings.

Selecting the best diagnostic test for malaria depends on the situation. In resource-limited settings, a blood smear is the primary option. For faster results, especially in areas with high P. falciparum prevalence, an RDT might be preferred. If confirmation or a more precise parasite identification is needed, or if initial tests are unclear, a PCR test could be used, although its availability is more limited. You can always check with your local malaria hospital for more information on malaria diagnosis.

How is Malaria Treated?

Malaria is treated with antimalarial medications that target the malaria parasites in the patient's bloodstream. The choice of treatment depends on factors such as the species of malaria parasite causing the infection, the severity of the illness, the patient's age and medical history, and the presence of any drug resistance in the area.

Antimalarial Medications

• Artemisinin-based Combination Therapies (ACTs): ACTs are currently the most effective treatment for uncomplicated malaria caused by Plasmodium falciparum, the most deadly malaria parasite. They combine an artemisinin derivative with another antimalarial drug to provide fast and effective parasite clearance.
• Chloroquine: Chloroquine was once widely used to treat malaria caused by chloroquine-sensitive Plasmodium species. However, due to widespread drug resistance, it is no longer recommended as a first-line malaria treatment in many regions. Chloroquine may still be effective in areas where the malaria parasites remain susceptible to the drug.
• Other antimalarial drugs: Depending on the specific circumstances, other malaria medications may be used for treatment. These drugs are often reserved for cases of severe malaria, infections with drug-resistant parasites, or individuals unable to tolerate first-line therapies.

Supportive Care

Along with antimalarial medications, supportive care is essential for managing symptoms and preventing complications. This might include:

• Fluids and electrolytes: Intravenous fluids are often necessary to address dehydration caused by fever and vomiting.
• Pain relievers: Medications like paracetamol can help manage fever and muscle aches.
• Blood transfusions: In severe cases with severe anaemia, blood transfusions might be needed.
• Anticonvulsants: These medications can be used to control seizures in cases of cerebral malaria.

How can Malaria be Prevented?

Malaria prevention is crucial, especially if you live in or are travelling to an area with a high risk of infection. Here are some key strategies for malaria prevention:

• Malaria vaccine: The malaria vaccine is an important component of malaria prevention efforts. Currently, the RTS,S/AS01 (RTS,S) vaccine, also known as Mosquirix, yet to be available in India, is the first and only vaccine approved for the prevention of malaria. The vaccine works by targeting the Plasmodium falciparum parasite, which is the most deadly species of malaria parasite. It stimulates the immune system to produce antibodies against the parasite, reducing the risk of infection and severe malaria disease.
• Use of Insecticide-Treated Bed Nets (ITNs): Sleeping under ITNs can provide significant protection against mosquito bites, particularly during the hours when Anopheles mosquitoes are most active (usually from dusk to dawn). ITNs are treated with insecticides that kill or repel mosquitoes, reducing the risk of malaria transmission while sleeping.
• Indoor Residual Spraying (IRS): IRS involves spraying insecticides on the interior walls of houses and other structures to kill mosquitoes that come into contact with the treated surfaces. This approach can help reduce mosquito populations and prevent indoor transmission of malaria.
• Personal protection measures: In addition to bed nets, individuals can protect themselves from mosquito bites by wearing long-sleeved clothing, pants, and socks, especially during peak mosquito activity hours. Applying insect repellents containing DEET, picaridin, or other EPA-approved ingredients can also help repel mosquitoes.
• Environmental management: Eliminating or reducing malaria mosquito breeding sites can help control mosquito populations and reduce malaria transmission. This includes draining stagnant water, covering or treating water storage containers, and clearing vegetation where mosquitoes may breed.
• Chemoprophylaxis: Travellers visiting malaria-endemic areas may take antimalarial medications as a preventive measure to reduce the risk of infection. The choice of medication depends on factors such as the destination's malaria risk, the traveller's health status, and any contraindications or drug resistance issues.

Conclusion

Malaria remains a significant global health challenge, where a combination of personal protective measures and community-based interventions can offer effective strategies for prevention and control. So, spread the word, practice prevention, and let's work together to ensure a healthier, malaria-free future for all. If you or someone you know needs medical assistance or information about malaria, don't hesitate to reach out to Malaria Doctors at Max Hospitals for expert guidance and care.