NIMR

Eric Rogier, Nastassia Battle, Catherine Bakari, Misago D. Seth, Douglas Nace, Camelia Herman, Achut Barakoti, Rashid A. Madebe, Celine I. Mandara, Beatus M. Lyimo, David J. Giesbrecht, Zachary R. Popkin-Hall, Filbert Francis, Daniel Mbwambo, Issa Garimo, Sijenunu Aaron, Abdallah Lusasi, Fabrizio Molteni, Ritha Njau, Jane A. Cunningham, Samwel Lazaro, Ally Mohamed, Jonathan J. Juliano, Jeffrey A. Bailey, Venkatachalam Udhayakumar & Deus S. Ishengoma

Plasmodium falciparum with the histidine rich protein 2 gene (pfhrp2) deleted from its genome can escape diagnosis by HRP2-based rapid diagnostic tests (HRP2-RDTs). The World Health Organization (WHO) recommends switching to a non-HRP2 RDT for P. falciparum clinical case diagnosis when pfhrp2 deletion prevalence causes ≥ 5% of RDTs to return false negative results. Tanzania is a country of heterogenous P. falciparum transmission, with some regions approaching elimination and others at varying levels of control. In concordance with the current recommended WHO pfhrp2 deletion surveillance strategy, 100 health facilities encompassing 10 regions of Tanzania enrolled malaria-suspected patients between February and July 2021. Of 7863 persons of all ages enrolled and providing RDT result and blood sample, 3777 (48.0%) were positive by the national RDT testing for Plasmodium lactate dehydrogenase (pLDH) and/or HRP2. A second RDT testing specifically for the P. falciparum LDH (Pf-pLDH) antigen found 95 persons (2.5% of all RDT positives) were positive, though negative by the national RDT for HRP2, and were selected for pfhrp2 and pfhrp3 (pfhrp2/3) genotyping. Multiplex antigen detection by laboratory bead assay found 135/7847 (1.7%) of all blood samples positive for Plasmodium antigens but very low or no HRP2, and these were selected for genotyping as well. Of the samples selected for genotyping based on RDT or laboratory multiplex result, 158 were P. falciparum DNA positive, and 140 had sufficient DNA to be genotyped for pfhrp2/3. Most of these (125/140) were found to be pfhrp2+/pfhrp3+, with smaller numbers deleted for only pfhrp2 (n = 9) or only pfhrp3 (n = 6). No dual pfhrp2/3 deleted parasites were observed. This survey found that parasites with these gene deletions are rare in Tanzania, and estimated that 0.24% (95% confidence interval: 0.08% to 0.39%) of false-negative HRP2-RDTs for symptomatic persons were due to pfhrp2 deletions in this 2021 Tanzania survey. These data provide evidence for HRP2-based diagnostics as currently accurate for P. falciparum diagnosis in Tanzania.

Published at: 2024-04-08

Prevalence of non-falciparum malaria infections among asymptomatic individuals in four regions of Mainland Tanzania

Zachary R. Popkin-Hall, Misago D. Seth, Rashid A. Madebe, Rule Budodo, Catherine Bakari, Filbert Francis, Dativa Pereus, David J. Giesbrecht, Celine I. Mandara, Daniel Mbwambo, Sijenunu Aaron, Abdallah Lusasi, Samwel Lazaro, Jeffrey A. Bailey, Jonathan J. Juliano, Julie R. Gutman & Deus S. Ishengoma

Recent studies point to the need to incorporate the detection of non-falciparum species into malaria surveillance activities in sub-Saharan Africa, where 95% of the world’s malaria cases occur. Although malaria caused by infection with Plasmodium falciparum is typically more severe than malaria caused by the non-falciparum Plasmodium species P. malariae, P. ovale spp. and P. vivax, the latter may be more challenging to diagnose, treat, control and ultimately eliminate. The prevalence of non-falciparum species throughout sub-Saharan Africa is poorly defined. Tanzania has geographical heterogeneity in transmission levels but an overall high malaria burden.

Published at: 2024-03-23

Microsatellites reveal high polymorphism and high potential for use in anti-malarial efficacy studies in areas with different transmission intensities in mainland Tanzania

Deus S. Ishengoma, Celine I. Mandara, Rashid A. Madebe, Marian Warsame, Billy Ngasala, Abdunoor M. Kabanywanyi, Muhidin K. Mahende, Erasmus Kamugisha, Reginald A. Kavishe, Florida Muro, Renata Mandike, Sigsbert Mkude, Frank Chacky, Ritha Njau, Troy Martin, Ally Mohamed, Jeffrey A. Bailey & Abebe A. Fola

Tanzania is currently implementing therapeutic efficacy studies (TES) in areas of varying malaria transmission intensities as per the World Health Organization (WHO) recommendations. In TES, distinguishing reinfection from recrudescence is critical for the determination of anti-malarial efficacy. Recently, the WHO recommended genotyping polymorphic coding genes, merozoite surface proteins 1 and 2 (msp1 and msp2), and replacing the glutamate-rich protein (glurp) gene with one of the highly polymorphic microsatellites in Plasmodium falciparum to adjust the efficacy of antimalarials in TES. This study assessed the polymorphisms of six neutral microsatellite markers and their potential use in TES, which is routinely performed in Tanzania.

Published at: 2024-03-15

Menstrual Health and hygiene knowledge among post menarche adolescent girls in urban and rural Tanzania

Robert M. Njee, Calister P. Imeda, Said M. Ali, Adiel K. Mushi, Doris D. Mbata, Albert W. Kapala, Emmanuel A. Makundi, Vitus A. Nyigo, Albert M. Majura, Winfrida O. Akyoo, Yolanda J. Mbatia, Germana T. Baraka, Judith M. Msovela, Ester S. Ngadaya, Mbazi F. Senkoro, Hamisi M. Malebo

Adolescent girls’ capacity to lead healthy lives and perform well in school has been hampered by their lack of awareness about menstruation and the requirements for its hygienic management. Lack of enabling infrastructure, improper menstrual supplies, and limited socioeconomic support for good menstrual health and cleanliness are characteristics of schools in Africa South of the Sahara. We evaluated school-age girls’ knowledge of menstrual hygiene and identified bottlenecks that could affect policy and programming for menstrual health and hygiene. A school-based cross-sectional study involved 8,012 adolescent school girls in the age group of 11–18 years (mean age = 14.9 years). The study evaluated students’ knowledge of menstrual health and hygiene (MHH) from the viewpoints of schools and communities using a combination of qualitative and quantitative approaches. Data was collected using self-administered surveys, focus group discussions, in-depth interviews, and site observations. Girls’ older age (AOR = 1.62, P 0.001), having a female guardian (AOR = 1.39: P = 001), and having a parent in a formal job (AOR = 1.03: P 0.023) were positively associated with Menstrual health and Hygiene Knowledge. MHH knowledge levels varied significantly between girls attending government (53.3) and non-government schools (50.5%, P = 0.0001), although they were comparable for girls attending rural and urban schools. Only 21% of the study’s schools had at least one instructor who had received training in MHH instruction for students. We have established that the majority of adolescent girls in schools have inadequate knowledge on menstrual health and hygiene, and that school teachers lack the skills to prepare and support young adolescents as they transition into puberty. Concerted actions aimed at building supportive policy are paramount, for school-aged teenagers to learn about and reap the long-term advantages of good menstrual health practices.

Published at: 2024-03-11

Trends of Plasmodium falciparum molecular markers associated with resistance to artemisinins and reduced susceptibility to lumefantrine in Mainland Tanzania from 2016 to 2021

Catherine Bakari, Celine I. Mandara, Rashid A. Madebe, Misago D. Seth, Billy Ngasala, Erasmus Kamugisha, Maimuna Ahmed, Filbert Francis, Samwel Bushukatale, Mercy Chiduo, Twilumba Makene, Abdunoor M. Kabanywanyi, Muhidin K. Mahende, Reginald A. Kavishe, Florida Muro, Sigsbert Mkude, Renata Mandike, Fabrizio Molteni, Frank Chacky, Dunstan R. Bishanga, Ritha J. A. Njau, Marian Warsame, Bilali Kabula, Ssanyu S. Nyinondi, Naomi W. Lucchi, Eldin Talundzic, Meera Venkatesan, Leah F. Moriarty, Naomi Serbantez, Chonge Kitojo, Erik J. Reaves, Eric S. Halsey, Ally Mohamed, Venkatachalam Udhayakumar & Deus S. Ishengoma

Background Therapeutic efficacy studies (TESs) and detection of molecular markers of drug resistance are recommended by the World Health Organization (WHO) to monitor the efficacy of artemisinin-based combination therapy (ACT). This study assessed the trends of molecular markers of artemisinin resistance and/or reduced susceptibility to lumefantrine using samples collected in TES conducted in Mainland Tanzania from 2016 to 2021.

Published at: 2024-03-09

Evidence of artemisinin partial resistance in North-western Tanzania: clinical and drug resistance markers study

Deus Simon Ishengoma, Celine Isaack Mandara, Catherine Bakari, Abebe A Fola, Rashid A Madebe, Misago Seth, Filbert Francis, Creyton Buguzi, Ramadhan Moshi, Issa Garimo, Samwel Lazaro, Sijenunu Aaron, Abdallah Lusasi, Frank Chacky, Ally Mohamed, Ritha Njau, Jovin Kitau, Charlotte Rasmussen, Jeffrey A Bailey, Jonathan J. Juliano, Marian Warsame

Artemisinin-based combination therapies (ACTs) are the recommended antimalarial drugs for the treatment of uncomplicated malaria. The recent emergence of artemisinin partial resistance (ART-R) in Rwanda, Uganda and Eritrea is of great concern. In Tanzania, a nationwide molecular malaria surveillance in 2021 showed a high prevalence of the Kelch13 (K13) 561H mutation in Plasmodium falciparum from the north-western region, close to the border with Rwanda and Uganda. This study was conducted in 2022 to evaluate the efficacy of artemether-lumefantrine (AL) and artesunate-amodiaquine (ASAQ) for the treatment of uncomplicated falciparum malaria and to confirm the presence of ART-R in Tanzania.

Published at: 2024-02-01

Publication Archive

  • 2024 (6 publications)
  • 2023 (5 publications)