Recognizing the burden
The global tally of malaria cases reached 247 million in 2021 compared to 245 million in 2020 and 232 million in 2019. Malaria cases continued to rise between 2020 and 2021, but at a slower rate than in the period 2019 to 2020.
There were an estimated 619 000 malaria deaths globally in 2021 compared to 625 000 in the first year of the pandemic. In 2019, before the pandemic struck, the number of deaths stood at 568 000.
Estimating the impact
In 2020 the WHO African Region was home to 95% of all malaria cases and 96% of deaths. Children under 5 years of age accounted for about 80% of all malaria deaths in the Region.
Four African countries accounted for just over half of all malaria deaths worldwide: Nigeria (31.9%), the Democratic Republic of the Congo (13.2%), United Republic of Tanzania (4.1%) and Mozambique (3.8%).
Eleven countries with the highest burden of malaria globally largely held the line against malaria during the pandemic: Burkina Faso, Cameroon, the Democratic Republic of the Congo, Ghana, India, Mali, Mozambique, the Niger, Nigeria, Uganda and the United Republic of Tanzania. Malaria deaths in these countries fell from an estimated 444 600 in 2020 to 427 854 in 2021, while cases increased from 165 million to 168 million in this same timeframe.
Prevention and control
Early diagnosis and treatment of malaria reduces disease, prevents deaths and contributes to reducing transmission. WHO recommends that all suspected cases of malaria be confirmed using parasite-based diagnostic testing (through either microscopy or a rapid diagnostic test). Diagnostic testing enables health providers to swiftly distinguish between malarial and non-malarial fevers, facilitating appropriate treatment. While PCR can be used to detect asymptomatic infections in some settings, the potential programme value of detecting low-density infections that are microscopy-negative but PCR-positive is unclear.
Malaria burden of disease
Global Burden of Disease (GBD) study assesses mortality and disability from hundreds of diseases, injuries, and risk factors around the world.
The Global Burden of Disease is a critical resource for informed policymaking.
Malaria incidence and prevalence
WHO’s World malaria report offers in-depth information on the latest trends in malaria control and elimination at global, regional and country levels. The report highlights progress towards global targets and describes opportunities and challenges for curbing and eliminating the disease. This year’s report includes a special analysis on the impact of disruptions to malaria prevention, diagnosis and treatment during the COVID-19 pandemic.
Disease surveillance for malaria control: an operational manual
The aim of this manual by the WHO is to provide guidance to malaria-endemic countries in designing and managing surveillance systems for malaria control and elimination, so that malaria programmes can obtain more complete, and more accurate information on malaria incidence and mortality, which can be used to help plan and monitor the programme.
In a study with a sample of 5873 suspected malaria cases in meso-america, malaria tests were requested in less than 10% of all cases (exception of Nicaragua and Colombia). More cases were tested in areas with active transmission than areas without cases. Travel history was not systematically recorded in any country.
What is the cause of malaria?
Malaria is caused by Plasmodium parasites. Four Plasmodium species (Plasmodium falciparum, Plasmodium vivax, Plasmodium ovale and Plasmodium malariae) give disease in humans, and humans are their only relevant reservoir.
Transmission requires an intermediate mosquito (anopheles) host, which is found worldwide. Following exposure (an infected mosquito bite) the incubation period varies between one and four weeks in most cases. Depending on the plasmodium species involved, much longer incubation periods are possible.
The clinical presentation of malaria depends very much on the pattern and intensity of malaria transmission in the area of residence, which determines the degree of protective immunity acquired and, in turn, the clinical disease profile.
What is PCD?
Passive case detection (PCD) is perhaps the most critical element for malaria surveillance in all transmission settings, and it is particularly relevant in elimination settings to prevent re-establishing transmission in disease-free areas. PCD encompasses the detection of malaria cases in people who seek care, usually with symptoms, from health providers or community health workers.
WHO. Global Malaria Programme. Disease surveillance for malaria elimination: an operational manual. Geneva: World Health Organization; 2012.
What is the role of Malaria rapid diagnostic tests?
Malaria rapid diagnostic tests (RDTs) assist in the diagnosis of malaria by providing evidence of the presence of malaria parasites in human blood. RDTs are an alternative to diagnosis based on clinical grounds or microscopy, particularly where good quality microscopy services cannot be readily provided.
Variations occur between products, such as targets and formats, though the principles of the tests are similar. Malaria RDTs detect specific antigens (proteins) produced by malaria parasites in the blood of infected individuals. Some RDTs can detect only one species (Plasmodium falciparum or P. vivax) while others detect multiple species (P. falciparum, P. vivax, P. malariae and P. ovale). Blood for the test is commonly obtained from a finger-prick.
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