What is Malaria? How Does the Malaria Rapid Test Kit Work?
Despite being preventable and treatable, malaria continues to threaten billions of people around the world every year. Malaria is a mosquito-borne disease caused by protozoan parasites of the Plasmodium genus in the phylum Apicomplexa. While more than 200 types of Plasmodium have been discovered, only five species of Plasmodium have been observed to affect humans: Plasmodium falciparum (P. falciparum), Plasmodium malariae (P. malariae), Plasmodium vivax (P. vivax), Plasmodium ovale (P. ovale), and Plasmodium knowlesi (P. knowlesi). Among these species, P. falciparum is the most prevalent across Africa, whereas P. vivax is the most common worldwide.
All malaria species transmit to people through the bites of infective female Anopheles mosquitoes. When an infected mosquito bites a person, immature forms of the parasite, called sporozoites, are released into the bloodstream. Once the plasmodium enters the host’s body, it migrates to the liver or another vertebrate body tissue to mature and multiply. Some parasites can lay dormant in the liver for as many as years, while others return to the bloodstream to infect red blood cells and multiply until the cells rupture. As the number of parasites within the bloodstream increase with each rupture, symptoms of malaria can ensue. Read along to learn more about malaria, its geographical distribution, symptoms, diagnosis, and best methods to protect yourself.
How common is malaria?
While its incidence in temperate climates has diminished significantly throughout the recent decades, malaria is still a common and consequential infection in many tropical and subtropical regions of Africa, Asia, and Latin America. According to Our World in Data, 96% of all deaths caused by malaria in 2019 occurred on the African continent. Children under the age of 5 accounted for over 55% of all malaria-linked deaths in 2019. Still, malaria incidence and malaria-linked deaths are falling both worldwide and across Africa. In fact, the latest data by Our World in Data demonstrates that the global death toll of malaria has fallen by almost 40% between the years 2000 and 2015.
What are the signs and symptoms of malaria?
The signs and symptoms of malaria typically develop within 7 to 30 days after exposure to the parasite. Symptoms and pathogenicity of malaria may depend on various factors, including the patient’s age, health status, and medical history, along with the type of plasmodium responsible for the infection. Indeed, patients may experience mild to no symptoms if they have a history of malaria infections or if they have been using preventive medicine. Likewise, infections caused by certain plasmodium species, such as P. vivax, P. ovale, and P. malariae may lay dormant in the host body for up to years. In fact, infections with P. vivax and P. ovale may remain in the host’s liver for several years while infections with P. malariae may remain in the blood for up to decades. These infections may cause relapses after long periods with no noticeable symptoms if left untreated.
Malaria often presents with flu-like symptoms such as fever, chills, sweating, headaches, cough, fatigue, muscle pain, nausea, diarrhea, and vomiting. As the infection progresses, symptoms include jaundice, enlarged liver, rapid breathing, and anemia. Fever and other symptoms may be experienced as episodes that appear, disappear, and follow each other in a cyclical pattern. Among various types of plasmodium, P. malariae is recognized as the most common cause of severe disease and complications linked to malaria. In severe cases of malaria, the parasites cause damage to the internal organs of the patient and lead to symptoms such as severe anemia, hematuria, impaired consciousness, metabolic acidosis, blood clotting issues, and seizures. If not treated immediately, these symptoms can be followed quickly by life-threatening complications such as liver failure, kidney failure, pulmonary edema, severe dehydration, acute respiratory distress syndrome, cerebral malaria, and coma, or lead to death.
How can you test for malaria?
The main methods used to diagnose malaria include microscopy, rapid antigen tests, and nucleic acid amplification tests such as polymerase chain reaction (PCR) assays. PCR-based methods such as conventional PCR, real-time multiplex PCR, and reverse transcriptase PCR detect targeted malaria genes in blood samples. The sensitivity of PCR-based methods allows for identifying infections in asymptomatic and submicroscopic patients that may be missed by microscopy and rapid diagnostic tests (RDTs). However, this method may not be applicable in remote and/or resource-limited areas with limited access to laboratory technology and specialized personnel. Microscopic examination of thick and thin blood films remains the golden standard in detecting parasitemia in the blood. Here, the sensitivity and specificity of the results depend heavily on the skill of the personnel performing the examination. Moreover, detecting and quantifying parasitemia may take time, leading to delays in treatment. Compared to PCR-based methods, microscopy also offers limited sensitivity in detecting patients with lower levels of parasitemia.
Finally, rapid diagnostic tests (RDTs) detect antigens specific to various malaria species in blood samples. These assays typically come in immunochromatographic strips where the processed samples are added to one end of the assay, and lines on the strip surface depict the results. As the liquid travels along the surface of the strip, multiple lines of antibodies capture and immobilize the parasitic antigens that may be present in the collected sample. Each assay also contains a positive control to confirm the validity of the test. Although rapid diagnostic tests (RDTs) offer a quick and affordable method that is much easier to deploy in remote or resource-limited settings, currently available species-specific rapid diagnostic tests (RDTs) can only identify P. falciparum and P. vivax. For other species of malaria, these tests can only indicate the presence of a parasite. Some assays, such as our Malaria P.F Rapid Test Kit, detect only one species of Plasmodium, while multiplexing assays, such as our Malaria P.F/P. V Rapid Test Kit and Malaria P.F/Pan Rapid Test Kit can differentiate among multiple species.
How can you protect yourself against malaria?
Efforts to develop a vaccine against malaria have been ongoing since the 1960s. On October 2021, the World Health Organization (WHO) released a recommendation for the widespread use of the RTS, S/AS01 (RTS, S) malaria vaccine among children living in sub-Saharan Africa and other areas with moderate to high P. falciparum transmission. Alongside vaccination, anti-malarial treatment, and various forms of personal protection such as insecticide-treated bed nets (ITNs) and indoor residual spraying (IRS) have proven effective in reducing malaria-linked hospitalizations and deaths. If you would like to reduce the risk of infection further, it is recommended to remove still water sources nearby your home and wear covered clothes in places with a high risk of exposure to mosquitoes.
Mbanefo, A., & Kumar, N. (2020). Evaluation of Malaria Diagnostic Methods as a Key for Successful Control and Elimination Programs. Tropical Medicine and Infectious Disease, 5(2), 102. https://doi.org/10.3390/tropicalmed5020102
Schofield, L., & Grau, G. E. (2005). Immunological processes in malaria pathogenesis. Nature Reviews Immunology, 5(9), 722–735. https://doi.org/10.1038/nri1686