Malaria

 Key facts 

• Malaria is caused by Plasmodium parasites. The four parasites species that cause malaria in humans are Plasmodium falciparum, P.vivax, P. Malaria. A fifth species, P. Knowlesi, also causes malaria in some areas of Southeast Asia. 
• Malaria is primarily spread through the bites of infected Anopheles mosquitoes, which bite mainly between dusk and dawn.
• Common symptoms include fever, chills, headaches, nausea, vomiting, muscle pains and fatigue.  Server cases can jaundice, seizures, coma, or death. 
• Malaria is diagnosed through microscopic examination of blood smears or by rapid diagnostic tests (RDTs) that antigens derived from malaria parasites. 
• Malaria can be treated with anti-malarial medications. The choice of medication and the duration of treatment depends on the type of Plasmodium, the severity of symptoms, and the region where the infection was acquired. 
• Preventive measures include using insect repellent, sleeping under insecticide-treated bed nets, taking anti-malarial drugs (chemo prophylaxis) when travelling to high-risk areas, and implementing mosquito control programs (e.g. indoor residual spraying, larval control).
• Malaria is a major global health problem, particularly in sub-Saharan Africa, where the majority of cases and deaths occur. Children under five years old are especially vulnerable. 
• According to the World Health Organisation (WHO), there were an estimated 229 million cases of malaria worldwide in 2019, with approximately 409,000 deaths. Over 90% of these deaths occurred in Africa. 
• Malaria affects economic development by reducing productivity due to illness and death. It also places a significant burden on healthcare systems and families, especially in low-income countries. 
• Efforts to control and eliminate malaria include the development of new treatments, vaccines (such as RTS,S/AS01, also known as Mosquirix), and improved diagnostic tools. Public health initiatives focus on mosquito control, and prompt treatment. 

Overview 

Malaria is a life-threatening disease spread to humans by some type of mosquitoes. It is mostly found in tropical countries. It is preventable and curable. 

The infection is caused by a parasite and does not spread from person to person. 

Symptoms can be mild or life-threatening. Mild symptoms are fever, chills and headaches. Severe symptoms include fatigue, confusion, seizures and difficulty breathing. 

Infants, children under 5 years, pregnant women, travellers and people with HIV or AIDS are at higher risk of severe infections.

Malaria can be prevented by avoiding mosquito bites and with medicines. Treatments can stop mild cases from getting worse. 

Malaria mostly spreads to people through the bites of some infected female Anopheles mosquitoes. Blood transfusion and contaminated needles may also treatment malaria. The first symptoms may be mild, similar to many febrile illnesses, and difficulty to recognize as malaria. Left untreated, P. Falciparum malaria can progress to severe illness and death within 24 hours. 

There are 5 Plasmodium parasites species that cause malaria in humans and 2 of these species - P. Falciparum and P. Viva- pose the greatest threat. P. Falciparum is the deadliest malaria parasite and the most prevalent on the African continent.  P. Vivax is the dominant malaria in most countries outside of sub-Saharan Africa.  The other malaria species which can infect humans are P. Malaria and P. Knowlesi. 

Symptoms 

The most common early symptoms of malaria are fever, headache and chills. 

 

Symptoms usually start within 10 - 15 days of getting bitten by an infected mosquito. 

Symptoms may be mild for some people, especially for those who have had a malaria infection before.  Because some malaria symptoms are not specific, getting tested early is important. 

Some types of malaria can cause severe illness and death. Infants, children under 5 years, pregnant women, travellers and people with HIV or AIDS are at higher risk. Severe symptoms include: 

• Extreme tiredness and fatigue 
• Impaired consciousness 
• Multiple convulsions
• Difficulty breathing 
• Dark or bloody 
• Jaundice (yellowing of the eyes and skin)
• Abnormal bleeding. 

People with severe symptoms should get emergency care right away. Getting treatment early for mild malaria can stop the infection from becoming severe. 

Malaria infection during pregnancy can also cause premature delivery or delivery of a baby with low birth weight. 

Transmission 

• Vector: Female Anopheles mosquitoes.
• Cycle: When an infected mosquito bites a human, the parasites enter the bloodstream and travel to the liver, where they mature and reproduce. After multiplying, they re-enter the bloodstream and infect red blood cells. 

Diagnosis 

• Microscopy: Examination of blood smears under a microscope to identify malaria parasites.
• Rapid Diagnostic tests (RDTs): Detect antigens derived from malaria parasites. 

Treatment 

• Anti-malarial Medications: Treatment depends on the Plasmodium on species and the severity of the disease. 
• Artermisinin-based combination therapies (ACTs) for P. Falciparum. 
• Chloroquine for P. Ovale, and P. malaria in areas where there is no resistance. 
• Primaquine for the liver stage of P. Vivax and ovale to prevent relapse. 

Prevention

• Insecticide-Treated Bed Nets (ITNs): Effective in reducing mosquito bites while sleeping. 
• Indoor Residual Spraying (IRS): Spraying inside homes to kill mosquitoes. 
• Prophylactic Medications: for travelers to malaria-endemic areas, medications like atovaquone-proguanil, doxycycline, or mefloquine are recommended. 
• Vaccination: The ART,S/AS01 (Mosquirix) vaccine has been approved for use in children in malaria-endemic areas. 

Epidemiology

• Global Burden: In 2020, there were 241 million cases of malaria and 627,000 malaria deaths worldwide. 
• Regions affected: Sub-Saharan Africa carries the highest burden, but malaria is also present in parts of Asia, Latin America, and the Middle East. 

Challenges and Efforts 

• Drug Resistance: Resistance to anti-malarial drugs, particularly P. Falciparum resistance to ACTs, is  growing concern. 
• Insecticide Resistance: Resistance to commonly used insecticides in mosquitoes is also increasing.
• Funding and Resources: Sustained funding and resources are crucial for malaria control and eliminate programs. 

Recent Advances 

• New Vaccines: Research is ongoing to develop more effective malaria vaccines.
• Genetic Research: Efforts are being made to genetically modify mosquitoes to reduce their ability to transmit malaria.