Prevalence of malaria in Arusha Region in the northern Tanzania.

Background: The World Health Organization (WHO) reported an estimated 249 million malaria cases globally in 2023, of which 94% were reported from Africa. Tanzania, a Sub-Saharan African country, has an exceptionally high malaria prevalence (3.6 million in 2023). The aim of the present study was to assess malaria prevalence rates in the Arusha Region, northern Tanzania. This region is famous for its national parks and wildlife reserves, and it is visited by thousands of tourists from all over the world each year. The assessment of malaria prevalence in the region is important in the context of the necessity to administer antimalarial chemoprophylaxis to international travellers.

Material and methods: The study group consisted of 101 people, residents of the Karatu District in the Arusha Region, aged between 1 and 73 years, who volunteered to participate in the screening. Phase I of the study was conducted in July 2022 in the Karatu Lutheran Hospital in Karatu Town (located close to the Ngorongoro Conservation Area and the Serengeti National Park). During this phase a venous blood sample was collected from each patient. The samples were tested for malaria using a rapid diagnostic test (mRDT); the same samples were also used to measure haemoglobin concentration and next they were applied onto the Whatman FTA micro cards for further molecular diagnostics in Poland (phase II).

Results: mRDT detected two (2.0%) infections caused by Plasmodium (the etiological factor of malaria), the molecular tests (RT-PCR) confirmed the two positive results by mRDT but also detected infections in six other samples (7.9% in total). The study found that six patients were infected with the Plasmodium falciparum species, while two other subjects had co-infections (P. falciparum + P. ovale, P. falciparum + P. vivax + P. malariae).

Conclusions: The study findings confirm the prevalence of malaria in areas located close to national parks in northern Tanzania and support the use of antimalarial chemoprophylaxis in international travellers visiting the area. The present study found co-infections caused by four different species of Plasmodium species which supports the prevalence of different parasitic species in Sub-Saharan Africa and is in line with CDC reports but contrary to WHO reports which estimate that 100% of malaria cases in Sub-Saharan Africa are caused by P. falciparum.