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Scientific Reports Feb 2024Despite Plasmodium ovale curtisi (Poc) and wallikeri (Pow) being important human-infecting malaria parasites that are widespread across Africa and Asia, little is known...
Despite Plasmodium ovale curtisi (Poc) and wallikeri (Pow) being important human-infecting malaria parasites that are widespread across Africa and Asia, little is known about their genome diversity. Morphologically identical, Poc and Pow are indistinguishable and commonly misidentified. Recent rises in the incidence of Poc/Pow infections have renewed efforts to address fundamental knowledge gaps in their biology, and to develop diagnostic tools to understand their epidemiological dynamics and malaria burden. A major roadblock has been the incompleteness of available reference assemblies (PocGH01, PowCR01; ~ 33.5 Mbp). Here, we applied multiple sequencing platforms and advanced bioinformatics tools to generate new reference genomes, Poc221 (South Sudan; 36.0 Mbp) and Pow222 (Nigeria; 34.3 Mbp), with improved nuclear genome contiguity (> 4.2 Mbp), annotation and completeness (> 99% Plasmodium spp., single copy orthologs). Subsequent sequencing of 6 Poc and 15 Pow isolates from Africa revealed a total of 22,517 and 43,855 high-quality core genome SNPs, respectively. Genome-wide levels of nucleotide diversity were determined to be 2.98 × 10 (Poc) and 3.43 × 10 (Pow), comparable to estimates for other Plasmodium species. Overall, the new reference genomes provide a robust foundation for dissecting the biology of Poc/Pow, their population structure and evolution, and will contribute to uncovering the recombination barrier separating these species.
Topics: Animals; Humans; Plasmodium ovale; Parasites; Sequence Analysis, DNA; Malaria; Nigeria
PubMed: 38360879
DOI: 10.1038/s41598-024-54382-5 -
Annals of African Medicine 2023Given the challenges of microscopy, we compared its performance with SD-Bioline malaria rapid diagnostic test (MRDT) and polymerase chain reaction (PCR) and evaluated...
CONTEXT AND AIM
Given the challenges of microscopy, we compared its performance with SD-Bioline malaria rapid diagnostic test (MRDT) and polymerase chain reaction (PCR) and evaluated the time it took for positive results to become negative after treatment of children with acute uncomplicated malaria.
SUBJECTS AND METHODS
We present the report of 485 participants with complete MRDT, microscopy, and PCR data out of 511 febrile children aged 3-59 months who participated in a cohort study over a 12-month period in rural and urban areas of Ibadan, Nigeria. MRDT-positive children received antimalaria and tested at every visit over 28 days. Speciation was also carried out by PCR.
RESULTS
With microscopy as the gold standard, SD-Bioline™ had 95.2% sensitivity, 66.4% specificity, 67.5% positive predictive value (PPV), and 94.9 negative predictive value (NPV), while with PCR the findings were 84.3% sensitivity, 66.5% specificity, 72.7% PPV, and 80.1% NPV. PCR speciation of malaria parasites revealed 91.6% Plasmodium falciparum, 18.9% Plasmodium malariae, and 4.4% Plasmodium ovale. Among the 47 children with P. malariae infections, 66.0% were coinfected with P. falciparum, while 54.6% cases of P. ovale occurred as coinfections with P. falciparum. The median time to a negative MRDT was 23.2 days, while the median time to a negative malaria microscopy was 3.8 days. The two survival curves were significantly different.
CONCLUSIONS
The SD-Bioline MRDT performed well, with remarkable persistence of rapid test-positive for an average of 23 days post treatment. The prevalence of P. malaria is somewhat greater than expected.
Topics: Child; Humans; Cohort Studies; Rapid Diagnostic Tests; Nigeria; Malaria; Malaria, Falciparum; Plasmodium falciparum; Sensitivity and Specificity
PubMed: 38358148
DOI: 10.4103/aam.aam_220_21 -
Therapeutic Advances in Infectious... 2024We describe a 5-week-old term infant with severe congenital malaria in a non-endemic setting. She presented with diarrhea, poor feeding, lethargy, hepatosplenomegaly,...
We describe a 5-week-old term infant with severe congenital malaria in a non-endemic setting. She presented with diarrhea, poor feeding, lethargy, hepatosplenomegaly, and severe anemia. She was fortuitously diagnosed with malaria on routine blood smear, and successfully treated with intravenous artesunate. Subsequent history revealed maternal malaria diagnosis and treatment during pregnancy in Nigeria. This case underscores the importance of obtaining maternal exposure history and considering malaria testing in pregnant women and infants with unexplained illness. It also contributes to the limited literature on congenital malaria and severe malaria caused by .
PubMed: 38312850
DOI: 10.1177/20499361241229263 -
Cureus Dec 2023Malaria is a highly infectious disease transmitted through the bite of the Anopheles mosquito carrying the parasite of the Plasmodium genus; it presents with cyclical...
Malaria is a highly infectious disease transmitted through the bite of the Anopheles mosquito carrying the parasite of the Plasmodium genus; it presents with cyclical fevers, myalgias, and headaches. In the United States, the vast majority of malaria cases are reported in people who travel abroad, mainly to Africa.These cases are predominantly linked to Plasmodium falciparum or ovale and can be medically treated with artemisinin, chloroquine, or atovaquone-proguanil. We discuss a case of a 38-year-old female immigrant from Venezuela living at an immigration facility who presented to a hospital located on the United States-Mexico border with a two-day history of watery diarrhea, headache, and subjective fever. She had experienced mosquito bites and likely contracted the illness in Chiapas, Mexico during her trek from Peru to the United States. Her case was unique as she tested positive for dengue fever antibodies acquired from a previous infection and also contracted rhinovirus during her clinical course. Her diagnosis of malaria was confirmed with a peripheral blood smear that revealed ring forms with no gametocytes. This in tandem with her route of travel suggested infection with Plasmodium vivax. She was treated with chloroquine while the malaria culture was pending and continued to spike fevers every 24-36 hours while on medication. Once the culture was confirmed, she was treated with atovaquone-proguanil as maintenance therapy. She was subsequently discharged on primaquine for 14 days to prevent relapse.
PubMed: 38293001
DOI: 10.7759/cureus.51400 -
Nature Communications Jan 2024The worldwide decline in malaria incidence is revealing the extensive burden of non-malarial febrile illness (NMFI), which remains poorly understood and difficult to...
The worldwide decline in malaria incidence is revealing the extensive burden of non-malarial febrile illness (NMFI), which remains poorly understood and difficult to diagnose. To characterize NMFI in Senegal, we collected venous blood and clinical metadata in a cross-sectional study of febrile patients and healthy controls in a low malaria burden area. Using 16S and untargeted sequencing, we detected viral, bacterial, or eukaryotic pathogens in 23% (38/163) of NMFI cases. Bacteria were the most common, with relapsing fever Borrelia and spotted fever Rickettsia found in 15.5% and 3.8% of cases, respectively. Four viral pathogens were found in a total of 7 febrile cases (3.5%). Sequencing also detected undiagnosed Plasmodium, including one putative P. ovale infection. We developed a logistic regression model that can distinguish Borrelia from NMFIs with similar presentation based on symptoms and vital signs (F1 score: 0.823). These results highlight the challenge and importance of improved diagnostics, especially for Borrelia, to support diagnosis and surveillance.
Topics: Humans; Senegal; Cross-Sectional Studies; Malaria; Plasmodium; Fever; Borrelia
PubMed: 38272885
DOI: 10.1038/s41467-024-44800-7 -
Trends in Parasitology Mar 2024
Topics: Plasmodium ovale; Phylogeny
PubMed: 38272740
DOI: 10.1016/j.pt.2024.01.004 -
Prevalence of Falciparum and non-Falciparum Malaria in the 2014-15 Rwanda Demographic Health Survey.MedRxiv : the Preprint Server For... Jan 2024Malaria remains a major cause of morbidity in sub-Saharan Africa. Undetected asymptomatic falciparum malaria results in a large transmission reservoir and there is...
BACKGROUND
Malaria remains a major cause of morbidity in sub-Saharan Africa. Undetected asymptomatic falciparum malaria results in a large transmission reservoir and there is evidence of increasing non-falciparum malaria as malaria is controlled in Africa, both resulting in challenges for malaria control programs.
METHODS
We performed quantitative real time PCR for 4 malaria species in 4,596 individuals from the 2014-2015 Rwanda Demographic Health Survey. Bivariate models were used to determine species-specific associations with risk factors.
RESULTS
Asymptomatic falciparum malaria, , and infection had broad spatial distribution across Rwanda. infection was rare. Overall infection prevalence was 23.6% (95%CI [21.7%, 26.0%]), with falciparum and non-falciparum at 17.6% [15.9%, 19.0%] and 8.3% [7.0%, 10.0%], respectively. Parasitemias tended to be low and mixed species infections were common, especially where malaria transmission was the highest. Falciparum infection was associated with socio-econiomic status, rural residence and low altitude. Few risk factors were associated with non-falciparum malaria.
CONCLUSIONS
Asymptomatic falciparum malaria and non-falciparum malaria are common and widely distributed across Rwanda. Continued molecular monitoring of is needed to monitor these threats to malaria control in Africa.
PubMed: 38260604
DOI: 10.1101/2024.01.09.24301054 -
The Journal of Infectious Diseases Apr 2024
Topics: Humans; Plasmodium ovale; Plasmodium malariae; Malaria; Plasmodium
PubMed: 38243611
DOI: 10.1093/infdis/jiae015 -
PLOS Global Public Health 2024Malaria is endemic in the Central region of Ghana, however, the ecological and the seasonal variations of Plasmodium population structure and the intensity of malaria...
Malaria is endemic in the Central region of Ghana, however, the ecological and the seasonal variations of Plasmodium population structure and the intensity of malaria transmission in multiple sites in the region have not been explored. In this cross-sectional study, five districts in the region were involved. The districts were Agona Swedru, Assin Central and Gomoa East (representing the forest zone) and Abura-Asebu-Kwamankese and Cape Coast representing the coastal zone. Systematically, blood samples were collected from patients with malaria. The malaria status was screened with a rapid diagnostic test (RDT) kit (CareStart manufactured by Access Bio in Somerset, USA) and the positive ones confirmed microscopically. Approximately, 200 μL of blood was used to prepare four dried blood spots of 50μL from each microscopy positive sample. The Plasmodium genome was sequenced at the Malaria Genome Laboratory (MGL) of Wellcome Sanger Institute (WSI), Hinxton, UK. The single nucleotide polymorphisms (SNPs) in the parasite mitochondria (PfMIT:270) core genome aided the species identification of Plasmodium. Subsequently, the complexity of infection (COI) was determined using the complexity of infection likelihood (COIL) computational analysis. In all, 566 microscopy positive samples were sequenced. Of this number, Plasmodium genome was detected in 522 (92.2%). However, whole genome sequencing was successful in 409/522 (72.3%) samples. In total, 516/522 (98.8%) of the samples contained P. falciparum mono-infection while the rest (1.2%) were either P. falciparum/P. ovale (Pf/Po) (n = 4, 0.8%) or P. falciparum/P. malariae/P. vivax (Pf/Pm/Pv) mixed-infection (n = 2, 0.4%). All the four Pf/Po infections were identified in samples from the Assin Central municipality whilst the two Pf/Pm/Pv triple infections were identified in Abura-Asebu-Kwamankese district and Cape Coast metropolis. Analysis of the 409 successfully sequenced genome yielded between 1-6 P. falciparum clones per individual infection. The overall mean COI was 1.78±0.92 (95% CI: 1.55-2.00). Among the study districts, the differences in the mean COI between ecological zones (p = 0.0681) and seasons (p = 0.8034) were not significant. However, regression analysis indicated that the transmission of malaria was more than twice among study participants aged 15-19 years (OR = 2.16, p = 0.017) and almost twice among participants aged over 60 years (OR = 1.91, p = 0.021) compared to participants between 20-59 years. Between genders, mean COI was similar except in Gomoa East where females recorded higher values. In conclusion, the study reported, for the first time, P. vivax in Ghana. Additionally, intense malaria transmission was found to be higher in the 15-19 and > 60 years, compared to other age groups. Therefore, active surveillance for P. vivax in Ghana and enhanced malaria control measures in the 15-19 year group years and those over 60 years are recommended.
PubMed: 38236793
DOI: 10.1371/journal.pgph.0002718 -
MedRxiv : the Preprint Server For... Dec 2023Recent studies point to the need to incorporate non-falciparum species detection into malaria surveillance activities in sub-Saharan Africa, where 95% of malaria cases...
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 infection is typically more severe, diagnosis, treatment, and control for , spp., and 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 species. was most prevalent, with and spp. detected at lower prevalence (<5%) in all four regions. was not detected. Malaria elimination efforts in Tanzania will need to account for these non-falciparum species.
PubMed: 38234751
DOI: 10.1101/2023.12.28.23300584