Artemisinin Partial Resistance Mutations in Zanzibar and Tanzania Suggest Regional Spread and African Origins, 2023.

Artemisinin partial resistance (ART-R), driven by Plasmodium falciparum K13 mutations, threatens malaria control. Zanzibar is vulnerable to ART-R spread but lacks recent molecular surveillance. We sequenced samples in Zanzibar and mainland Tanzania collected in 2022-2024.

Antibody responses to SG6, AgSAP, and SAMSP1 following Anopheline salivary exposure.

Background: Current methods to determine exposure to malaria-infected mosquitoes via entomologic investigations are technically challenging and can be inaccurate in low transmission settings. Antibody responses to mosquito salivary antigens (MSA) like gSG6-P1 have been used as biomarkers of exposure to mosquito bites.

Methods: This study investigates two novel gambiae antigens, AgSAP and SAMSP1, as potential biomarkers of vector exposure.

Artemisinin Partial Resistance Mutations in Zanzibar and Tanzania Suggest Regional Spread and African Origins, 2023.

Artemisinin partial resistance (ART-R), driven by Plasmodium falciparum K13 mutations, threatens malaria control. Zanzibar is vulnerable to ART-R spread but lacks recent molecular surveillance. We sequenced samples in Zanzibar and mainland Tanzania collected in 2022-2024.

Diversity of anopheline species and malaria transmission dynamics in high-altitude areas of western Cameroon.

Background: Assessing vector bionomics and their role in transmission is crucial to improving vector control strategies. Several entomological studies have been conducted to describe malaria transmission in different eco-epidemiological settings in Cameroon; however, data gaps persist, particularly in the highland areas. This study aimed to characterize malaria vectors in three localities along an altitudinal gradient in the western region: Santchou (700 m), Dschang (1400 m) and Penka Michel (1500 m).

Integrating mobility, travel survey, and malaria case data to understand drivers of malaria importation to Zanzibar, 2022-2023.

Background: Zanzibar has achieved historic reductions in malaria incidence, but high connectivity to mainland Tanzania and imported cases remain a challenge to "last mile" malaria elimination.

Methods: To understand factors driving malaria importation, we collected travel histories and demographics of malaria cases presenting to 94 health facilities across Zanzibar's main island, Unguja, from 2022-2023. We also analyzed population mobility data-self-reported travel at the outbound Dar es Salaam ferry terminal and Meta colocation and movement distribution-to examine movement patterns between Unguja and mainland Tanzania.

Understanding the Epidemiology of Malaria in Zanzibar through Molecular and Serological Analysis of Samples collected during Reactive Case Detection.

Background: The Zanzibar archipelago has been a pre-elimination region for malaria thanks to rigorous control interventions, but recent surges in malaria cases have been observed. The contribution of non-falciparum species to the current malaria situation is unknown.

Methods: This study investigates the seroepidemiology of falciparum and non-falciparum malaria species in Zanzibar.

Epidemiology of Relapsing and Falciparum Malaria in the Highlands of Cameroon: An Integrated Community Survey of Human Infection and Vector Abundance.

Despite global malaria control efforts, the disease caused 263 million cases and 597,000 deaths in 2023. While accounts for most cases in Africa, non-falciparum species, such as spp. and , can cause relapse infections and are increasingly recognized as significant contributors to human disease.

Distribution of non-falciparum malaria among symptomatic malaria patients in Dschang, West Region of Cameroon.

Background: Malaria is a vector-borne parasitic disease that continues to be a global public health threat. Five different species of the genus (, and cause malaria in Sub-Saharan Africa. Previous cross-sectional surveys from 2013 and 2017 indicated the circulation of in the West region of Cameroon, prompting an investigation into the prevalence of all non-falciparum malaria parasite species in this region.

Seasonal variation and interspecies dynamics among and species in Bagamoyo, Tanzania.

Background: Malaria control in sub-Saharan Africa is typically focused on (), but non-falciparum species like () and () appear to be rising in prevalence, especially in East Africa.

Methods: We conducted polymerase chain reaction (PCR)-based screening of 7,173 asymptomatic individuals over 5 years of age in coastal Tanzania from 2018-2022, employing real-time 18S rRNA PCR assays for and , followed by / detection. positivity was compared across seasons and demographic groups, and interactions between species were analyzed via binomial regression.

Diversity, abundance of anopheline species, and malaria transmission dynamics in high-altitude areas of western Cameroon.

Background: Assessing vector bionomics is crucial to improving vector control strategies. Several entomological studies have been conducted to describe malaria transmission in different eco-epidemiological settings in Cameroon; knowledge gaps persist, particularly in highland areas. This study aimed to characterize malaria vectors in three localities along an altitudinal gradient in the western region: Santchou (700 m), Dschang (1400 m), and Penka Michel (1500 m).

Assessment of Malaria Rapid Diagnostic Tests and Histidine-Rich Protein 2 Deletions among Asymptomatic Children and Adults in Bagamoyo, Tanzania.

Malaria rapid diagnostic tests (mRDTs) that detect histidine-rich protein 2 (HRP2) remain the mainstay of falciparum malaria diagnosis in Sub-Saharan Africa. Understanding their test characteristics when used for surveillance in asymptomatic populations is important. We explored the rate of false-positive and false-negative mRDT results among asymptomatic persons >5 years old screened for malaria at schools and clinics in the rural Bagamoyo District using 18S ribosomal RNA real-time polymerase chain reaction (qPCR) as the reference test.

Evidence of SARS-CoV-2 Spread in Rural Tanzania During the First 6 Months of the Global COVID-19 Pandemic.

In the first 6 months of the coronavirus disease 2019 pandemic, limited testing clouded understanding of the extent of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission in Africa. In particular, Tanzania halted all testing and reporting of SARS-CoV-2 cases after May 2020, not resuming until June 2021. In July-August 2020, we performed a seroprevalence survey in rural Bagamoyo district, 40 km outside Dar es Salaam.

Development of new real-time PCR assays for detection and species differentiation of Plasmodium ovale.

Background: The parasite species Plasmodium ovalecurtisi (P. ovalecurtisi) and Plasmodium ovalewallikeri (P. ovalewallikeri), formerly known as Plasmodium ovale, are endemic across multiple African countries.

Reduced risk of SARS-CoV-2 infection among household contacts with recent vaccination and past COVID-19 infection: results from 2 multisite case-ascertained household transmission studies.

Households are a primary setting for the transmission of SARS-CoV-2. We examined the role of prior SARS-CoV-2 immunity on the risk of infection in household close contacts. Households in the United States with an individual who tested positive for SARS-CoV-2 from September 2021 to May 2023 were enrolled if the index case's illness began ≤ 6 days prior.

Strong isolation by distance and evidence of population microstructure reflect ongoing transmission in Zanzibar.

Background: The Zanzibar archipelago of Tanzania has become a low-transmission area for . Despite being considered an area of pre-elimination for years, achieving elimination has been difficult, likely due to a combination of imported infections from mainland Tanzania and continued local transmission.

Methods: To shed light on these sources of transmission, we applied highly multiplexed genotyping utilizing molecular inversion probes to characterize the genetic relatedness of 282 isolates collected across Zanzibar and in Bagamoyo district on the coastal mainland from 2016 to 2018.

Microheterogeneity of Transmission Shapes Submicroscopic Malaria Carriage in Coastal Tanzania.

Background: Asymptomatic carriage of malaria parasites persists even as malaria transmission declines. Low-density infections are often submicroscopic, not detected with rapid diagnostic tests (RDTs) or microscopy but detectable by polymerase chain reaction (PCR).

Methods: To characterize submicroscopic Plasmodium falciparum carriage in an area of declining malaria transmission, asymptomatic persons >5 years of age in rural Bagamoyo District, Tanzania, were screened using RDT, microscopy, and PCR.

Detection of P. malariae using a new rapid isothermal amplification lateral flow assay.

Background: While Plasmodium falciparum and Plasmodium vivax cause the majority of malaria cases and deaths, infection by Plasmodium malariae and other Plasmodium species also causes morbidity and mortality. Current understanding of these infections is limited in part by existing point-of-care diagnostics that fail to differentiate them and have poor sensitivity for low-density infections. Accurate diagnosis currently requires molecular assays performed in well-resourced laboratories.

Evaluation of Malaria Rapid Diagnostic Test Performance and pfhrp2 Deletion in Tanzania School Surveys, 2017.

As part of malaria nationwide monitoring and evaluation initiatives, there is an increasing trend of incorporating malaria rapid diagnostic tests (mRDTs) in surveys conducted within primary schools to detect malaria parasites. However, mRDTs based on the detection of histidine-rich protein 2 (HRP2) are known to yield false-positive results due to persistent antigenemia, and false-negative results may result from low parasitemia or Plasmodium falciparum hrp2/3 gene deletion. We evaluated diagnostic performance of an HRP2 and pan-parasite lactate dehydrogenase (HRP2/pLDH) mRDT against polymerase chain reaction (PCR) for detection of P.

Real-time PCR detection of mixed Plasmodium ovale curtisi and wallikeri infections in human and mosquito hosts.

Plasmodium ovale curtisi (Poc) and Plasmodium ovale wallikeri (Pow) represent distinct non-recombining Plasmodium species that are increasing in prevalence in sub-Saharan Africa. Though they circulate sympatrically, co-infection within human and mosquito hosts has rarely been described. Separate 18S rRNA real-time PCR assays that detect Poc and Pow were modified to allow species determination in parallel under identical cycling conditions.

A novel duplex qualitative real-time PCR assay for the detection and differentiation of Plasmodium ovale curtisi and Plasmodium ovale wallikeri malaria.

Background: spp. infections are endemic across multiple African countries and are caused by two distinct non-recombining species, () and (). These species are thought to differ in clinical symptomatology and latency, but existing diagnostic assays have limited ability to detect and distinguish them.

Epidemiology of Plasmodium malariae and Plasmodium ovale spp. in Kinshasa Province, Democratic Republic of Congo.

Reports suggest non-falciparum species are an underappreciated cause of malaria in sub-Saharan Africa but their epidemiology is ill-defined, particularly in highly malaria-endemic regions. We estimated incidence and prevalence of PCR-confirmed non-falciparum and Plasmodium falciparum malaria infections within a longitudinal study conducted in Kinshasa, Democratic Republic of Congo (DRC) between 2015-2017. Children and adults were sampled at biannual household surveys and routine clinic visits.

Detection of using a new rapid isothermal amplification lateral flow assay.

is found worldwide and causes chronic parasitism in its human hosts. We developed a diagnostic assay that uses rapid, isothermal recombinase polymerase amplification (RPA) and lateral-flow-strip detection. Using 18S rRNA plasmid DNA, the assay demonstrates a detection limit of 10 copies /μL (~1.