Papers by ABDALLAH LUSASI
Parasites & vectors, Mar 23, 2024
Background Recent studies point to the need to incorporate the detection of non-falciparum specie... more 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 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. Methods To estimate the prevalence of malaria species in Mainland Tanzania, we randomly selected 1428 samples from 6005 asymptomatic isolates collected in previous cross-sectional community surveys across four regions and analyzed these by quantitative PCR to detect and identify the Plasmodium species. Plasmodium falciparum was the most prevalent species in all samples, with P. malariae and P. ovale spp. detected at a lower prevalence (< 5%) in all four regions; P. vivax was not detected in any sample. The results of this study indicate that malaria elimination efforts in Tanzania will need to account for and enhance surveillance of these non-falciparum species.
Understanding Antenatal Care Service Quality for Malaria in Pregnancy through Supportive Supervision Data in Tanzania
The American journal of tropical medicine and hygiene, Mar 5, 2024
medRxiv (Cold Spring Harbor Laboratory), Feb 1, 2024
Background: Artemisinin-based combination therapies (ACTs) are the recommended antimalarial drugs... more Background: 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. Methods: This single-arm study evaluated the efficacy of AL and ASAQ in eligible children aged six months to 10 years at Bukangara Dispensary in Karagwe District, Kagera Region. Clinical and parasitological responses were monitored for 28 days according to standard WHO protocol. Mutations in K13 gene and extended haplotypes with these mutations were analysed using Sanger and whole genome sequencing data, respectively. Findings: 176 children (88 in each AL and ASAQ group) were enrolled and all achieved the defined outcomes. PCR-corrected adequate clinical and parasitological response (ACPR) was 98.3% (95% CI: 90.8-100) and 100.0% (95% CI: 95.8-100) for AL and ASAQ, respectively. Parasitaemia on day 3 was observed in 11/88 (12.5%) and 17/88 (19.3%) in the AL and ASAQ groups, respectively. The half-life of parasitaemia was significantly higher (>6.5 hrs) in patients with parasitaemia on day 3 and/or mutations in K13 gene at enrolment. Most patients with parasitaemia on day 3 (8/11 = 72.7% in the AL group and 10/17 = 58.8% in the ASAQ group) had 561H mutation at enrolment. The parasites with K13 mutations were not similar to those from south-east Asia and Rwanda, but had the same core haplotype of a new 561H haplotype reported in Kagera in 2021. Interpretation: These findings confirm the presence of ART-R in Tanzania. A contextspecific strategy to respond to artemisinin partial resistance is urgently needed. Although both AL and ASAQ showed high efficacy, increased vigilance for reduced efficacy of these ACTs and detection of ART-R in other parts of the country is critical.
Recent studies point to the need to incorporate non-falciparum species detection into malaria sur... more 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 prevalence of these species throughout sub-Saharan Africa is poorly defined. Tanzania has geographically heterogeneous transmission levels but an overall high malaria burden. In order to estimate the prevalence of malaria species in Mainland Tanzania, 1,428 samples were randomly selected from 6,005 asymptomatic isolates collected in cross-sectional community surveys across four regions and analyzed via qPCR to detect each Plasmodium species. P. falciparum was most prevalent, with P. malariae and P. ovale spp. detected at lower prevalence (<5%) in all four regions. P. vivax was not detected. Malaria elimination efforts in Tanzania will need to account for these non-falciparum species.
BackgroundEmergence of artemisinin partial resistance (ArtR) inPlasmodium falciparumin East Afric... more BackgroundEmergence of artemisinin partial resistance (ArtR) inPlasmodium falciparumin East Africa is a growing threat to the efficacy of artemisinin combination therapies (ACT) and the global efforts for malaria elimination. The emergence ofPfkelch13R561H in Rwanda, raised concern about the impact in neighboring Tanzania, despite contemporary surveys suggesting limited 561H in the country. In addition, regional concern over resistance affecting sulfadoxine-pyrimethamine (SP) which is used for chemoprevention strategies is high.MethodsTo enhance longitudinal monitoring, the Molecular Surveillance of Malaria in Tanzania (MSMT) project was launched in 2020 with the goal of assessing and mapping the profile of antimalarial resistance across transmission zones. Community and clinic samples were assessed for resistance polymorphisms using a high throughput molecular inversion probe platform.FindingsGenotyping of 6,278 samples collected in 2021 revealed a focus ofPfkelch13561H mutants in ...
BackgroundTanzania adopted and has been implementing the World Health Organization (WHO) recommen... more BackgroundTanzania 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 assessed the prevalence and risk of malaria infections among asymptomatic individuals living in a hyperendemic area which has high prevalence of artemisinin partial resistant parasites in Kyerwa District of Kagera region, North-western Tanzania.MethodsThis was a community-based cross-sectional survey that recruited participants from five villages of Kyerwa district in Kagera region. Demographic, anthropometric, clinical, parasitological, types of houses inhabited and socio-economic status (SES) data were collected using electronic capture tools running on Open Data Kit (ODK). Risk factors associated with malaria infections were determined by univa...
Frontiers in Cellular and Infection Microbiology
Recent developments in molecular biology and genomics have revolutionized biology and medicine ma... more 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 and re-emerging pathogens. Most low and middle income countries (LMICs) with the highest burden of infectious diseases still largely lack the capacity to generate and perform bioinformatic analysis of genomic data. These countries have also not deployed tools based on CRISPR-Cas technologies. For LMICs including Tanzania, it is critical to focus not only on the process of generation and analysis of data generated using such tools, but also on the utilization of the findings for policy and decision making. Here we discuss the promise and challenges of NGS and CRISPR-Cas in the context of malaria as Africa moves towards malaria elimination. ...
Malaria Journal, 2021
Background Tanzania started implementing single screening and treatment (SST) for all pregnant wo... more Background Tanzania started implementing single screening and treatment (SST) for all pregnant women attending their first antenatal care (ANC) visits in 2014, using malaria rapid diagnostic tests (RDTs) and treating those who test positive according to the national guidelines. However, there is a paucity of data to show the acceptability of SST to both pregnant women and health care workers (HCWs), taking into consideration the shortage of workers and the added burden of this policy to the health system. This study assessed the perceptions and opinions of health service users and providers to determine the acceptability of SST policy. Methods Pregnant women and HCWs in eight health facilities in two districts of Lindi region (Kilwa and Lindi) were interviewed using semi-structured questionnaires with open and close-ended questions. Both qualitative and quantitative data were collected, including demographic characteristics, women’s experience, their perception on SST and challenges...
Recent data indicate that non-Plasmodium falciparumspecies may be more prevalent than previously ... more Recent data indicate that non-Plasmodium falciparumspecies may be more prevalent than previously realized in sub-Saharan Africa, the region where 95% of the world’s malaria cases occur. AlthoughPlasmodium malariae, Plasmodium ovalespp., andPlasmodium vivaxare generally less severe thanP. falciparum, treatment and control are more challenging, and their geographic distributions are not well characterized. In order to characterize the distribution of malaria species in Mainland Tanzania (which has a high burden and geographically heterogeneous transmission levels), we randomly selected 3,284 samples from 12,845 samples to determine presence and parasitemia of different malaria species. The samples were collected from cross-sectional surveys in 100 health facilities across ten regions and analyzed via quantitative real-time PCR to characterize regional positivity rates for each species.P. falciparumwas most prevalent, butP. malariaeandP. ovalewere found in all regions except Dar es Sal...
BMJ Global Health, 2021
IntroductionDisease-specific ‘vertical’ programmes and health system strengthening (HSS) ‘horizon... more IntroductionDisease-specific ‘vertical’ programmes and health system strengthening (HSS) ‘horizontal’ programmes are not mutually exclusive; programmes may be implemented with the dual objectives of achieving both disease-specific and broader HSS outcomes. However, there remains an ongoing need for research into how dual objective programmes are operationalised for optimum results.MethodsA qualitative study encompassing four grantee programmes from two partner countries, Tanzania and Sierra Leone, in the Comic Relief and GlaxoSmithKline ‘Fighting Malaria, Improving Health’ partnership. Purposive sampling maximised variation in terms of geographical location, programme aims and activities, grantee type and operational sector. Data were collected via semi-structured interviews. Data analysis was informed by a general inductive approach.Results51 interviews were conducted across the four grantees. Grantee organisations structured and operated their respective projects in a manner gener...
Malaria Journal
Background It has been more than 20 years since the malaria epidemiologic shift to school-aged ch... more 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 communities. Intermittent Preventive Treatment of malaria in schoolchildren (IPTsc) has proven to be an effective tool to shrink this reservoir. As of 3rd June 2022, the World Health Organization recommends IPTsc in moderate and high endemic areas. Even so, for decision-makers, the adoption of scientific research recommendations has been stifled by real-world implementation challenges. This study presents methodology, challenges faced, and mitigations used in the evaluation of the implementation of IPTsc using dihydroartemisinin-piperaquine (DP) in three councils (Handeni District Council (DC), Handeni Town Council (TC) and Kilindi DC) of Tanga Reg...
Plasmodium falciparum pfhrp2andpfhrp3gene deletions among patients enrolled at 100 health facilities throughout Tanzania: February to July 2021
Plasmodium falciparumwith the histidine rich protein 2 gene (pfhrp2) deleted from its genome can ... more Plasmodium falciparumwith 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 forP. falciparumclinical case diagnosis whenpfhrp2deletion prevalence causes ≥ 5% of RDTs to return false negative results. Tanzania is a country of heterogenousP. falciparumtransmission, with some regions approaching elimination and others at varying levels of control. In concordance with the current recommended WHOpfhrp2deletion surveillance strategy, 100 health facilities encompassing 10 regions of Tanzania enrolled malaria-suspected patients between February and July 2021. Of 7,863 persons of all ages enrolled and providing RDT result and blood sample, 3,777 (48.0%) were positive by the national RDT testing forPlasmodiumlactate dehydrogenase (pLDH) and/or HRP2. A second RDT testing specifically for theP. falciparumLDH (Pf-pLDH) antigen found 95...
Malaria Journal
Background In areas of high transmission, malaria in pregnancy (MiP) primarily causes asymptomati... more Background In areas of high transmission, malaria in pregnancy (MiP) primarily causes asymptomatic infections; these infections nonetheless increase the risk of adverse maternal and fetal outcomes. In 2014, Tanzania initiated a single screening and treatment (SST) strategy for all pregnant women at their first antenatal care (ANC) visit using malaria rapid diagnostic tests (RDT) for surveillance purposes. However, there is paucity of data on the effectiveness of SST in the prevention of MiP. The objective of this study was to estimate the number of asymptomatic infections among pregnant women detected by SST, which would have been missed in the absence of the policy. Methods Data from pregnant women attending their first ANC visits between October 2017 and June 2018, including gestational age, history of fever, and RDT results, were abstracted from ANC registers in eight health centres in two randomly selected districts, Kilwa and Lindi, in Lindi Region. The proportion of symptomati...
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Papers by ABDALLAH LUSASI