Malaria, a parasitic disease spread through the bites of infected female Anopheles mosquitoes, continues to pose a significant health challenge. Tanzania, located in East Africa, is recognized as one of the countries with the highest malaria burden worldwide. Approximately 93% of the population of Mainland Tanzania lives in transmission areas and is at risk. The disease has historically been the leading cause of illness and death, deeply affecting public health and socio-economic development. Efforts to control malaria have been underway for decades, but the scale of transmission keeps the country at the forefront of the global fight. The national strategic goal is to substantially reduce this burden so malaria is no longer a major obstacle to development.
Current Epidemiological Burden and Impact
Tanzania consistently ranks among the top countries globally for malaria cases and deaths, accounting for 3.3% of global cases and 4.3% of global deaths in 2023. This places Tanzania among the four nations responsible for over half of all malaria fatalities worldwide. The parasite responsible for the vast majority of infections is Plasmodium falciparum, which accounts for 96% of all cases in Tanzania. This species is the most virulent and contributes significantly to severe disease and death rates.
The national average prevalence of malaria in Mainland Tanzania, measured by the presence of the parasite in children under five years old, was reported to be 8.1% in the 2022 Tanzania Demographic and Health Survey and Malaria Indicator Survey (TDHS-MIS). This figure masks significant regional variation, with prevalence ranging from less than 1% in some highland areas to as high as 24% near Lake Victoria. Malaria is the top cause of hospital outpatient and inpatient visits.
The economic and social toll of the disease is substantial, contributing significantly to poverty and underdevelopment. Direct costs include healthcare expenditure for treatment and prevention, while indirect costs stem from lost productivity and income. Overall, the financial burden has been estimated to consume over 1% of the country’s Gross Domestic Product (GDP).
Geographic and Demographic Distribution
Malaria transmission in Tanzania is highly heterogeneous. Transmission intensity is often categorized, with about 60% of the population living in areas with stable perennial transmission. The highest-burden areas are typically found in the regions surrounding Lake Victoria and the Southern and Western zones, where prevalence rates can reach 15% to 24%. These areas have consistent high temperatures and abundant water sources, which provide ideal breeding grounds for the Anopheles mosquito vector.
In contrast, regions located in the Southern Highlands, such as Arusha and Kilimanjaro, exhibit much lower transmission, sometimes with prevalence rates below 1%. These areas benefit from higher altitudes and cooler temperatures, which restrict the mosquito’s lifecycle. However, even these low-transmission zones are vulnerable to occasional epidemics, particularly with changes in climate patterns.
Demographically, the disease disproportionately targets children under five years old and pregnant women. Children are susceptible because their developing immune systems cannot mount an effective defense against the parasite. For pregnant women, a malaria infection can lead to severe anemia, stillbirth, low birth weight, and maternal death.
The semi-autonomous archipelago of Zanzibar has successfully reduced its prevalence to very low levels, often below 1%. This success is attributed to aggressive and sustained control measures, implemented more intensely than on the Mainland.
National Malaria Control Strategies and Interventions
The Tanzanian National Malaria Control Programme (NMCP) bases its strategy on several core interventions to combat the disease. A primary focus is on vector control, specifically through the widespread distribution of Insecticide-Treated Nets (ITNs). Long-lasting insecticidal nets are provided free of charge to vulnerable groups like children and pregnant women. The use of ITNs has been a major factor in protecting households and reducing overall transmission.
Another key vector control tool is Indoor Residual Spraying (IRS), which involves coating the interior walls of homes with long-lasting insecticide. IRS is used selectively and strategically, primarily targeting high-transmission regions or areas prone to outbreaks. The deployment of IRS complements ITNs, providing a second layer of defense against mosquitoes.
For case management, the national policy mandates parasitological confirmation using either microscopy or Rapid Diagnostic Tests (RDTs) before treatment is initiated. This ensures that antimalarial drugs are used only when necessary, slowing the development of drug resistance. The first-line treatment for uncomplicated P. falciparum malaria is Artemisinin-based Combination Therapies (ACTs), which are provided free or at minimal cost at public health facilities.
Preventive measures specifically target pregnant women through Intermittent Preventive Treatment in Pregnancy (IPTp). This involves administering doses of the antimalarial drug Sulfadoxine-Pyrimethamine (SP) at scheduled antenatal care visits. This measure helps to clear any asymptomatic malaria infection in the mother, protecting both her and the unborn child. Furthermore, the NMCP emphasizes a strong surveillance system to monitor the disease and rapidly respond to potential outbreaks.
Progress, Challenges, and Emerging Issues
Malaria control efforts in Tanzania have yielded measurable success over the past two decades. The national strategic plan aims to significantly reduce prevalence in children under five. While the 2022 survey showed prevalence at 8.1%, the long-term trend indicates a considerable reduction from previously much higher rates. These gains are directly linked to the scaled-up distribution of ITNs and the adoption of ACTs as the standard treatment.
Challenges to Progress
Despite this progress, several significant challenges threaten to stall or reverse the gains made. A major obstacle is the growing insecticide resistance in the primary mosquito vectors. The emergence of genetic mutations compromises the effectiveness of pyrethroids, the insecticide class used in nets and spraying programs. Continuous monitoring is necessary to ensure the insecticides currently in use remain effective against the evolving mosquito population.
Maintaining consistent and sufficient funding remains a persistent challenge, with the majority of financing coming from external partners like the U.S. President’s Malaria Initiative (PMI) and the Global Fund. Logistical difficulties in reaching remote rural populations, combined with weak health system infrastructure, also impede the consistent delivery of prevention tools and timely treatment. Furthermore, reports indicate that some regions have seen an increase in malaria caseloads in recent years, including a rise of 1.9 million cases between 2019 and 2023.
Emerging Issues
Emerging issues require adaptation of the control strategy. Climate change is a concern, as rising temperatures and shifting rainfall patterns can expand the geographic range of the Anopheles mosquito, potentially introducing malaria to previously unaffected highland areas. The potential introduction of new tools, such as the WHO-recommended RTS,S malaria vaccine, offers a new layer of protection for children. Successful implementation of a vaccine, alongside continued surveillance and resistance management, will be instrumental in pushing Tanzania closer to its goal of malaria elimination.