Non-falciparum malaria infections are as prevalent as <i>P. falciparum</i> among Tanzanian schoolchildren

Sendor, Rachel; Mitchell, C. Madeline; Chacky, Frank; Mohamed, Ally; Mhamilawa, Lwidiko E.; Molteni, Fabrizio; Nyinondi, Ssanyu; Kabula, Bilali; Mkali, Humphrey; Reaves, Erik J.; Serbantez, Naomi; Kitojo, Chonge; Makene, Twilumba; Kyaw, Thwai; Muller, Meredith; Mwanza, Alexis; Eckert, Erin; Parr, Jonathan B.; Lin, Jessica T.; Juliano, Jonathan J.; Ngasala, Billy

doi:10.1101/2022.06.07.22275625

Cited by 6 publications

(10 citation statements)

References 37 publications

(80 reference statements)

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“…In addition, the schoolchildren survey mostly identified P. ovale spp. as singlespecies infections and P. malariae as mixed with P. falciparum [6], whereas we found similar proportions of single-species and mixed-species P. malariae infections and most of our P. ovale spp. samples were mixed with P. falciparum.…”

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confidence: 44%

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Malaria species prevalence among asymptomatic individuals in four regions of Mainland Tanzania

Popkin Hall,

Seth,

Madebe

et al. 2023

Preprint

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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.

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confidence: 44%

“…Previous work in Mainland Tanzania has characterized non-falciparum prevalence in schoolchildren (5-16 years) [6] and non-falciparum positivity rates among symptomatic patients [12]. In schoolchildren, P. ovale spp.…”

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confidence: 99%

Malaria species prevalence among asymptomatic individuals in four regions of Mainland Tanzania

Popkin Hall,

Seth,

Madebe

et al. 2023

Preprint

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“…They have both been detected throughout Africa, but usually at much lower prevalence than P. falciparum [25]. Both are frequently detected in co-infections with P. falciparum rather than as mono-infections [15,[25][26][27][28], although exceptions have been noted [29]. P. ovale spp.…”

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confidence: 99%

Malaria species positivity rates among symptomatic individuals across regions of differing transmission intensities in Mainland Tanzania

Popkin Hall,

Seth,

Madebe

et al. 2023

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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, 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. falciparum was most prevalent, but P. malariae and P. ovale were found in all regions except Dar es Salaam, with high levels (>5%) of P. ovale in seven regions (70%). The highest positivity rate of P. malariae was 4.5% in Mara region and eight regions (80%) had positivity rates ≥1%. We also detected three P. vivax infections in the very low-transmission Kilimanjaro region. While most samples that tested positive for non-falciparum malaria were co-infected with P. falciparum, 23.6% (n = 13/55) of P. malariae and 14.7% (n = 24/163) of P. ovale spp. samples were mono-infections. P. falciparum remains by far the largest threat, but our data indicate that malaria elimination efforts in Tanzania will require increased surveillance and improved understanding of the biology of non-falciparum species.

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“…This is important because Pm infections have lower parasite densities than Pf and can be missed by commonly used PCR assays. However, it is still likely to pick up the majority of Pm parasitemias detectable by qPCR as well as those contributing to febrile illness [15]. Thus, our assay fills a key gap in the malaria diagnostic portfolio and outperforms pan- Plasmodium RDTs.…”

Section: Discussionmentioning

confidence: 99%

Detection ofP. malariaeusing a new rapid isothermal amplification lateral flow assay

Assefa

Wamae

Hennelly

et al. 2023

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P. malariaeis found worldwide and causes chronic parasitism in its human hosts. We developed aP. malariae (Pm)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 (∼1.7 genome equivalents) and 100% analytical specificity. Testing in field samples showed 95% clinical sensitivity and 88% specificity compared to qPCR. Total assay time was 35 minutes. Combined with simplified DNA extraction methods, the assay has potential for future field-deployable point-of-care use to detect a parasite species that remains largely undiagnosed.

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Non-falciparum malaria infections are as prevalent as P. falciparum among Tanzanian schoolchildren

Cited by 6 publications

References 37 publications

Malaria species prevalence among asymptomatic individuals in four regions of Mainland Tanzania

Malaria species prevalence among asymptomatic individuals in four regions of Mainland Tanzania

Malaria species positivity rates among symptomatic individuals across regions of differing transmission intensities in Mainland Tanzania

Detection ofP. malariaeusing a new rapid isothermal amplification lateral flow assay

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