About
64
Publications
11,336
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
740
Citations
Introduction
Skills and Expertise
Current institution
Additional affiliations
July 2004 - June 2015
Publications
Publications (64)
Background: Recent initiatives have promoted the application of genomic data to determine the trends and patterns of malaria transmission and the impact of interventions. This study aimed to evaluate and identify the most effective genetic metrics for monitoring the genetic diversity of Plasmodium falciparum and its correlation with malaria transmi...
Background
Subpatent Plasmodium falciparum infections, defined as infections with parasite density below the detection limit of routine malaria diagnostic tests, contribute to infectious reservoirs, sustain transmission, and cause the failure of elimination strategies in target areas. This study assessed the prevalence of subpatent P. falciparum in...
Background
Recent reports showed the persistence of malaria transmission and disease burden in rural communities, which have limited the impact of ongoing control and elimination strategies. This study investigated the trends of malaria prevalence among community members from three regions of Mainland Tanzania with varying transmission intensities....
Background
The limited efficacy of the two recently approved malaria vaccines, RTS,S/AS01 and R21/Matrix- M™, highlights the need for alternative vaccine candidate genes. Plasmodium falciparum Reticulocyte Binding Protein Homologue 5 (Pfrh5) is a promising malaria vaccine candidate, given its limited polymorphism, its essential role in parasite sur...
Recent reports revealed a declining malaria burden, but non-malaria febrile illnesses (NMFIs) have either remained unchanged or increased. This study assessed the country-wide prevalence of NMFIs and their patterns across various malaria transmission settings in Mainland Tanzania. A cross-sectional study recruited patients aged ≥ 6 months from 86 h...
Background: Subpatent Plasmodium falciparum infections, defined as infections with parasitaemia density below the detection limit of routine malaria diagnostic tests, contribute to infectious reservoirs, sustain transmission, and cause the failure of elimination strategies in target areas. This study assessed the prevalence of and factors associate...
Background
In Africa, the first Plasmodium falciparum artemisinin partial resistance mutation, was Kelch13 (K13) 561H - detected and validated at appreciable frequency in Rwanda in 2014. Surveillance to better define the extent of the emergence in Rwanda and neighboring countries is critical.
Methods
We used novel liquid blood drop preservation co...
Background: Despite the implementation of different control interventions, infections in the communities (among asymptomatic and symptomatic individuals) still play a crucial role in sustaining malaria transmission. This study evaluated the performance of rapid diagnostic tests (RDTs), microscopy, and quantitative PCR (qPCR) in detecting malaria pa...
Background: The limited efficacy of the two malaria vaccines, RTS,S/AS01 and R21/Matrix M, which were recently approved vaccines by the World Health Organization, highlights the need for alternative vaccine candidate genes beyond these pre-erythrocytic-based vaccines. Plasmodium falciparum Reticulocyte Binding Protein Homologue 5 (Pfrh5) is a poten...
Plasmodium malariae is geographically widespread but neglected and may become more prevalent as P. falciparum declines. We completed the largest genomic study of African P. malariae to-date by performing hybrid capture and sequencing of 77 isolates from Cameroon (n=7), the Democratic Republic of the Congo (n=16), Nigeria (n=4), and Tanzania (n=50)...
Background
Artemether-lumefantrine (AL) is the first line anti-malarial drug for the treatment of uncomplicated malaria in Tanzania. The World Health Organization (WHO) recommends regular efficacy monitoring of anti-malarial drugs to inform case management policy decisions. This study assessed the safety and efficacy of AL for treating uncomplicate...
Background
In 2021, nationwide malaria molecular surveillance revealed a high prevalence of a validated artemisinin resistance marker, the kelch13 (k13) Arg561His mutation, in the Kagera region of northwestern Tanzania. We aimed to investigate the efficacy of artemether–lumefantrine and artesunate–amodiaquine and to confirm the presence of artemisi...
Background
The emergence of the artemisinin partial resistance (ART-R) mutation in the Plasmodium falciparum kelch13 gene (k13), Arg561His, in Rwanda and the regional presence of polymorphisms affecting sulfadoxine–pyrimethamine have raised concern in neighbouring Tanzania. The goal of this study was to assess the status of antimalarial resistance...
Background
Although Tanzania adopted and has been implementing effective interventions to control and eventually eliminate malaria, the disease is still a leading public health problem, and the country experiences heterogeneous transmission. Recent studies reported the emergence of parasites with artemisinin partial resistance (ART-R) in Kagera reg...
Background: Malaria is still a leading public health problem in Tanzania despite the implementation of effective interventions for the past two decades. Currently, the country experiences heterogeneous transmission and a higher malaria burden in some vulnerable groups, threatening the prospects for elimination by 2030. This study assessed the preva...
Background
In 2021 and 2023, the World Health Organization approved RTS,S/AS01 and R21/Matrix M malaria vaccines, respectively, for routine immunization of children in African countries with moderate to high transmission. These vaccines are made of Plasmodium falciparum circumsporozoite protein (PfCSP), but polymorphisms in the gene raise concerns...
Background
Artemisinin-based combination therapy (ACT) has been a major contributor to the substantial reductions in global malaria morbidity and mortality over the last decade. In Tanzania, artemether-lumefantrine (AL) was introduced as the first-line treatment for uncomplicated Plasmodium falciparum malaria in 2006. The World Health Organization...
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...
Background
The use of artemisinin-based combination therapy (ACT) is recommended by the World Health Organization for the treatment of uncomplicated falciparum malaria. Artemether-lumefantrine (AL) is the most widely adopted first-line ACT for uncomplicated malaria in sub-Saharan Africa (SSA), including mainland Tanzania, where it was introduced in...
Background
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 spe...
Background
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...
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 lumefantrin...
Background
Despite a recent reduction in malaria morbidity and mortality, the disease remains a major cause of morbidity and mortality in Tanzania. However, the malaria burden is heterogeneous with a higher burden in some regions compared to others, suggesting that stratification of malaria burden and risk/predictors of infections is critical to gu...
Background
In 2021 and 2023, the World Health Organization approved RTS,S/AS01 and R21/Matrix M malaria vaccines, respectively, for routine immunization of children in African countries with moderate to high transmission. These vaccines are made of Plasmodium falciparum circumsporozoite protein ( Pfcsp) but polymorphisms in this gene raises concern...
Recent studies point to the need to incorporate non-falciparum species detection into malaria surveillance activities in sub-Saharan Africa, where 95% of malaria cases occur. Although Plasmodium falciparum infection is typically more severe, diagnosis, treatment, and control for P. malariae, P. ovale spp., and P. vivax may be more challenging. The...
Background
Artemisinin-based combination therapies (ACTs) have been a major contributor to the substantial reductions in global malaria morbidity and mortality over the last decade. In Tanzania, artemether-lumefantrine (AL) was introduced as the first-line treatment for uncomplicated Plasmodium falciparum malaria in 2006. The WHO recommends regular...
Background
Tanzania is currently implementing therapeutic efficacy studies (TES) in areas of varying malaria transmission intensities as per the World Health Organization′s (WHO) recommendations. In TES, distinguishing reinfection from recrudescence is critical for the determination of antimalarial efficacy. Recently, the WHO recommended genotyping...
Background
Recent data indicate that non-Plasmodium falciparum species may be more prevalent than thought in sub-Saharan Africa. Although Plasmodium malariae, Plasmodium ovale spp., and Plasmodium vivax are less severe than P. falciparum, treatment and control are more challenging, and their geographic distributions are not well characterized.
Met...
Background: Emergence of artemisinin partial resistance (ArtR) in Plasmodium falciparum in East Africa is a growing threat to the efficacy of artemisinin combination therapies (ACT) and the global efforts for malaria elimination. The emergence of Pfkelch13 R561H in Rwanda, raised concern about the impact in neighboring Tanzania, despite contemporar...
Background: Use of artemisinin combination therapy (ACT) is recommended by the World Health Organization (WHO) for the treatment of uncomplicated falciparum malaria. Artemether-lumefantrine (AL) is the most widely adopted first-line ACT for uncomplicated malaria in sub-Saharan Africa (SSA), including mainland Tanzania, where it was introduced in De...
The genetic diversity of Plasmodium falciparum plays a crucial role in its ability to adapt to environmental changes, develop resistance to antimalarial drugs, and evade the host immune response. These adaptive mechanisms enable the parasite to persist despite extensive interventions. Understanding the genetic diversity of P. falciparum across diff...
Background
Despite significant decline in the past two decades, malaria is still a major public health concern in Tanzania; with over 93% of the population still at risk. Community knowledge, attitudes and practices (KAP), and beliefs are key in enhancing uptake and utilization of malaria control interventions, but there is a lack of information on...
Background: Tanzania adopted and has been implementing the World Health Organization (WHO) recommended interventions to control and eventually eliminate malaria. However, malaria is still a leading public health problem and the country experiences heterogeneous transmission; but the drivers of these patterns are not clearly known. This study assess...
Recent data indicate that non-Plasmodium falciparum species may be more prevalent than previously realized in sub-Saharan Africa, the region where 95% of the world's malaria cases occur. Although Plasmodium malariae, Plasmodium ovale spp., and Plasmodium vivax are generally less severe than P. falciparum, treatment and control are more challenging,...
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...
We describe the MalariaGEN Pf7 data resource, the seventh release of Plasmodium falciparum genome variation data from the MalariaGEN network. It comprises over 20,000 samples from 82 partner studies in 33 countries, including several malaria endemic regions that were previously underrepresented. For the first time we include dried blood spot sample...
Background
It has been more than 20 years since the malaria epidemiologic shift to school-aged children was noted. In the meantime, school-aged children (5–15 years) have become increasingly more vulnerable with asymptomatic malaria prevalence reaching up to 70%, making them reservoirs for subsequent transmission of malaria in the endemic communiti...
Background
Malaria rapid diagnostic tests (RDTs) based on the detection of the Plasmodium falciparum histidine-rich protein 2 (HRP2) antigen are widely used for detection of active infection with this parasite and are the only practical malaria diagnostic test in some endemic settings. External validation of RDT results from field surveys can confi...
Recent developments in molecular biology and genomics have revolutionized biology and medicine mainly in the developed world. The application of next generation sequencing (NGS) and CRISPR-Cas tools is now poised to support endemic countries in the detection, monitoring and control of endemic diseases and future epidemics, as well as with emerging...
Background
Histidine-rich protein 2 (HRP2)-based malaria rapid diagnostic tests (RDTs) are effective and widely used for the detection of wild-type Plasmodium falciparum infections. Although recent studies have reported false negative HRP2 RDT results due to pfhrp2 and pfhrp3 gene deletions in different countries, there is a paucity of data on the...
High‐throughput Plasmodium genomic data is increasingly useful in assessing prevalence of clinically important mutations and malaria transmission patterns. Understanding parasite diversity is important for identification of specific human or parasite populations that can be targeted by control programs, and to monitor the spread of mutations associ...
Background Despite high coverage and successes in malaria control strategies, some areas of Tanzania have indicated stagnantion or revesal of malaria burden. In malaria research, most studies are designed to assess drivers of malaria transmission focusing only on one dimension, single location while very few studies assess multiple components and t...
High-throughput Plasmodium genomic data is increasingly useful in assessing prevalence of clinically important mutations and malaria transmission patterns. Understanding parasite diversity is important for identification of specific human or parasite populations that can be targeted by control programs, and to monitor the spread of mutations associ...
Background
Despite high coverage and successes in malaria control strategies, some areas of Tanzania have indicated stagnantion or revesal of malaria burden. In malaria research, most studies are designed to assess drivers of malaria transmission focusing only on one dimension, single location while very few studies assess multiple components and t...
Background
The Tanzanian National Malaria Control Programme (NMCP) and its partners have been implementing regular therapeutic efficacy studies (TES) to monitor the performance of different drugs used or with potential use in Tanzania. However, most of the recent TES focused on artemether–lumefantrine, which is the first-line anti-malarial for the...
Background
The World Health Organization recommends regular therapeutic efficacy studies (TES) to monitor the performance of first and second-line anti-malarials. In 2016, efficacy and safety of artemether-lumefantrine (AL) for the treatment of uncomplicated falciparum malaria were assessed through a TES conducted between April and October 2016 at...
Background
Artemisinin-based combination therapy (ACT) is the first-line anti-malarial treatment of uncomplicated malaria in most malaria endemic countries, including Tanzania. Unfortunately, there have been reports of artemisinin resistance and ACT failure from South East Asia highlighting the need to monitor therapeutic efficacy of ACT in these c...
Background:
Artemether-lumefantrine (AL) is the recommended first-line artemisinin-based combination therapy (ACT) for the treatment of uncomplicated falciparum malaria in most of the malaria-endemic countries, including Tanzania. Recently, dihydroartemisinin-piperaquine (DP) has been recommended as the alternative anti-malarial to ensure effectiv...
Background
Although the recent decline of malaria burden in some African countries has been attributed to a scale-up of interventions, such as bed nets (insecticide-treated bed nets, ITNs/long-lasting insecticidal nets, LLINs), the contribution of other factors to these changes has not been rigorously assessed. This study assessed the trends of Pla...
Background:
Although death records are useful for planning and monitoring health interventions, such information is limited in most developing countries. Verbal autopsy (VA) interviews are alternatively used to determine causes of death in places without or with incomplete hospital records. This study was conducted to determine all causes and caus...
Background: Reliable supply of laboratory supportive services contributes significantly to the quality of HIV diagnostic services. This study assessed the status of supply chain management of laboratory supportive services and its potential implications on the quality of HIV diagnostic services in selected districts of Tanzania. Methods: The study...
Antimalarial drug resistance is an evolving global health security threat to malaria control. Early detection of Plasmodium falciparum resistance through therapeutic efficacy studies and associated genetic analyses may facilitate timely implementation of intervention strategies. The US President’s Malaria Initiative–supported Antimalarial Resistanc...
Background
Roll-out and implementation of antiretroviral therapy (ART) necessitated many countries in Sub-Saharan Africa to strengthen their national health laboratory systems (NHLSs) to provide high quality HIV diagnostic and supportive services. This study was conducted to assess the performance of health laboratories in provision of HIV diagnost...
Background:
Malaria continues to top the list of the ten most threatening diseases to child survival in Tanzania. The country has a functional policy for appropriate case management of malaria with rapid diagnostic tests (RDTs) from hospital level all the way to dispensaries, which are the first points of healthcare services in the national referr...
Abstract
Background: Since malaria rapid diagnostic tests (mRDTs) are widely used for
parasitological diagnosis and targeting of treatment with effective antimalarials,
this study assessed their performance for screening of patients to be enrolled in
clinical trials and other studies, particularly in areas with progressively declining
transmission....
Strong health laboratory systems and networks capable of providing high quality services are critical components of the health system and play a key role in routine diagnosis, care, treatment and disease surveillance. This study aimed to assess the readiness of the national health laboratory system (NHLS) and its capacity to support care and treatm...
Intermittent preventive treatment with sulfadoxine-pyrimethamine (IPTp-SP) is widely deployed in the control of pregnancy-associated malaria. However widespread SP resistance threatens its effectiveness. This study aimed at assessing diversity of Plasmodium species as well as identifying molecular markers of sulphadoxine resistance in the current s...
Background
The World Health Organization recommends that regular efficacy monitoring should be undertaken by all malaria endemic countries that have deployed artemisinin combination therapy (ACT). Although ACT is still efficacious for treatment of uncomplicated malaria, artemisinin resistance has been reported in South East Asia suggesting that sur...
Scaling up of Antiretroviral (ARV) drugs is crucial and should be a perpetual venture in developing countries in-order to increase the survival period of HIV/AIDS individuals. In Tanzania, information on the rate of patients considered as lost to follow up during treatment with ARVs is scarce. The objective of this study was to determine the rate o...
Long-term retention of patients in the rapidly expanding antiretroviral programs against HIV/AIDS is essential for the success of these programs. Unfortunately, high percentages of patients in need of treatment are lost to follow up in resource-poor settings. From June 2006 to March 2007 269 HIV-infected pregnant women were screened for participati...
Tuberculosis (TB) is one of the leading causes of adult mortality with 32% of the global population infected with Mycobacterium tuberculosis. The current control of TB depends mainly on case management using the Direct-Observed Treatment, Short-course (DOTs) regimen. Despite the measures taken, the disease burden is still on increase especially in...
