scholarly journals High prevalence of asymptomatic malaria infections in adults, Ashanti Region, Ghana, 2018

2020 ◽  
Vol 19 (1) ◽  
Author(s):  
Melina Heinemann ◽  
Richard O. Phillips ◽  
Christof D. Vinnemeier ◽  
Christina C. Rolling ◽  
Egbert Tannich ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Plasmodium Malariae ◽  
Asymptomatic Malaria ◽  
Forest Zone ◽  
Transmission Season ◽  
Ashanti Region ◽  
High Prevalence ◽  
Notable Increase ◽  
Asymptomatic Adult ◽  
Species Specific

Abstract Background Ghana is among the high-burden countries for malaria infections and recently reported a notable increase in malaria cases. While asymptomatic parasitaemia is increasingly recognized as a hurdle for malaria elimination, studies on asymptomatic malaria are scarce, and usually focus on children and on non-falciparum species. The present study aims to assess the prevalence of asymptomatic Plasmodium falciparum and non-falciparum infections in Ghanaian adults in the Ashanti region during the high transmission season. Methods Asymptomatic adult residents from five villages in the Ashanti Region, Ghana, were screened for Plasmodium species by rapid diagnostic test (RDT) and polymerase chain reaction (PCR) during the rainy season. Samples tested positive were subtyped using species-specific real-time PCR. For all Plasmodium ovale infections additional sub-species identification was performed. Results Molecular prevalence of asymptomatic Plasmodium infection was 284/391 (73%); only 126 (32%) infections were detected by RDT. While 266 (68%) participants were infected with Plasmodium falciparum, 33 (8%) were infected with Plasmodium malariae and 34 (9%) with P. ovale. The sub-species P. ovale curtisi and P. ovale wallikeri were identified to similar proportions. Non-falciparum infections usually presented as mixed infections with P. falciparum. Conclusions Most adult residents in the Ghanaian forest zone are asymptomatic Plasmodium carriers. The high Plasmodium prevalence not detected by RDT in adults highlights that malaria eradication efforts must target all members of the population. Beneath Plasmodium falciparum, screening and treatment must also include infections with P. malariae, P. o. curtisi and P. o. wallikeri.

scholarly journals High prevalence of asymptomatic malaria infections in adults, Ashanti Region, Ghana, 2018

2020 ◽  
Author(s):  
Melina Heinemann ◽  
Richard O. Phillips ◽  
Christof D. Vinnemeier ◽  
Christina Rolling ◽  
Egbert Tannich ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Plasmodium Species ◽  
Plasmodium Malariae ◽  
Asymptomatic Malaria ◽  
Forest Zone ◽  
Transmission Season ◽  
Ashanti Region ◽  
High Prevalence ◽  
Asymptomatic Adult ◽  
Species Specific

Abstract Background Ghana is among the high-burden countries for malaria infection and recently reported a notably increase in malaria cases. While asymptomatic parasitaemia is increasingly recognized as a hurdle for malaria elimination, studies on asymptomatic malaria are scarce and usually focus on children and on non-falciparum species. The present study aims to assess the prevalence of asymptomatic Plasmodium falciparum and non-falciparum infections in Ghanaian adults in the Ashanti region during the high transmission season. Methods Asymptomatic adult residents from five villages in the Ashanti Region, Ghana, were screened for Plasmodium species by rapid diagnostic test (RDT) and polymerase chain reaction (PCR) during the rainy season. Samples tested positive were subtyped using species-specific real-time PCR. For all Plasmodium ovale infections additional sub-species identification was performed. Results Molecular prevalence of asymptomatic Plasmodium infection was 284/391 (73%); only 126 (32%) infections were detected by RDT. While 266 (68%) participants were infected with Plasmodium falciparum, 33 (8%) were infected with Plasmodium malariae and 34 (9%) with P. ovale. The sub-species P. ovale curtisi and P. ovale wallikeri were identified to similar proportions. Non-falciparum infections usually presented as mixed infections with P. falciparum. Conclusions Most adult residents in the Ghanaian forest zone are asymptomatic Plasmodium carriers. The high Plasmodium prevalence not detected by RDT in adults highlights that malaria eradication efforts must target all members of the population. Beneath Plasmodium falciparum, screening and treatment must also include infections with P. malariae, P. o. curtisi and P. o. wallikeri.

scholarly journals High prevalence of asymptomatic malaria infections in adults, Ashanti Region, Ghana, 2018

2020 ◽  
Author(s):  
Melina Heinemann ◽  
Richard O. Phillips ◽  
Christof D. Vinnemeier ◽  
Christina Rolling ◽  
Egbert Tannich ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Plasmodium Malariae ◽  
Asymptomatic Malaria ◽  
Plasmodium Ovale ◽  
Forest Zone ◽  
Ashanti Region ◽  
Plasmodium Ovale Curtisi ◽  
High Prevalence ◽  
Asymptomatic Adult ◽  
Species Specific

Abstract Background Ghana is among the high-burden countries for malaria infection and recently reported a notably increase in malaria cases. While asymptomatic parasitemia is increasingly recognized as a hurdle for malaria elimination, studies on asymptomatic malaria are scarce and usually focus on children and on non-falciparum species. The present study aims to assess the prevalence of asymptomatic Plasmodium falciparum and non-falciparum infections in Ghanaian adults in the Ashanti region during the high transmission season. Methods Asymptomatic adult residents from five villages in the Ashanti Region, Ghana, were screened for Plasmodium spp. by rapid diagnostic test (RDT) and polymerase chain reaction (PCR) during the rainy season. Samples tested positive were subtyped using species-specific real-time PCR. For all P. ovale infections additional sub-species identification was performed.Results Molecular prevalence of asymptomatic Plasmodium infection was 284/391 (73%); only 126 (32%) infections were detected by RDT. While 266 (68%) participants were infected with Plasmodium falciparum, 33 (8%) were infected with Plasmodium malariae and 34 (9%) with Plasmodium ovale. The sub-species Plasmodium ovale curtisi and P. ovale wallikeri were identified to similar proportions. Non-falciparum infections usually presented as mixed infections with Plasmodium falciparum.Conclusions Most adult residents in the Ghanaian forest zone are asymptomatic Plasmodium carriers. The high Plasmodium prevalence not detected by RDT in adults highlights that malaria eradication efforts must target all members of the population. Beneath Plasmodium falciparum, screening and treatment must also include infections with Plasmodium malariae, P. ovale curtisi and P. ovale wallikeri .

scholarly journals Plasmodium falciparum DHFR and DHPS Mutations Are Associated With HIV-1 Co-Infection and a Novel DHPS Mutation I504T Is Identified in Western Kenya

2020 ◽  
Vol 10 ◽  
Author(s):  
Brandi K. Torrevillas ◽  
Sarah M. Garrison ◽  
Alexander J. McKeeken ◽  
Dharmeshkumar Patel ◽  
James T. Van Leuven ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Haplotype Diversity ◽  
Plasmodium Malariae ◽  
Drug Binding ◽  
Cross Resistance ◽  
Asymptomatic Malaria ◽  
Newly Diagnosed ◽  
Cross Sectional ◽  
Antifolate Resistance ◽  
Hiv 1

Antifolate resistance is significant in Kenya and presumed to result from extensive use and cross-resistance between antifolate antimalarials and antibiotics, including cotrimoxazole/Bactrim used for HIV-1 chemotherapy. However, little is known about antifolate-resistant malaria in the context of newly diagnosed HIV-1 co-infection prior to administration of HIV-1 chemotherapy. Blood samples from a cross-sectional study of asymptomatic adult Kenyans enrolled during voluntary HIV testing were analyzed by PCR for Plasmodium spp. More than 95% of volunteers with identifiable parasite species (132 HIV-1 co-infected) were infected with Plasmodium falciparum alone or P. falciparum with Plasmodium ovale and/or Plasmodium malariae. Deep sequencing was used to screen for mutations in P. falciparum dihydrofolate reductase (dhfr) (N51I, C59R, S108N, I164L) and dihydropteroate synthase (dhps) (S436H, A437G, K540E, A581G) from 1133 volunteers. Individual mutations in DHPS but not DHFR correlated with HIV-1 status. DHFR haplotype diversity was significantly different among volunteers by gender and HIV-1 status. DHPS haplotype diversity by HIV-1 status was significantly different between volunteers paired by age and gender, indicating that patterns of resistance were independent of these variables. Molecular simulations for a novel DHPS mutation (I504T) suggested that the mutated protein has increased affinity for the endogenous ligand DHPPP and decreased affinity for drug binding. A sub-group of monoclonal infections revealed that age and parasitemia were not correlated and enabled identification of a rare septuple-mutant haplotype (IRNL-HGEA). In our study, adult Kenyans newly diagnosed with HIV-1 infection were predominantly infected with moderately resistant P. falciparum, with patterns of infecting parasite genotypes significantly associated with HIV-1 status. Together with the discovery of DHPS I504T, these data indicate that antifolate resistance continues to evolve in Kenya. Further, they highlight the need to understand the effects of associated mutations on both fitness and resistance of P. falciparum in the context of HIV-1 co-infection to better inform treatment for asymptomatic malaria.

scholarly journals High Prevalence of Markers for Sulfadoxine and Pyrimethamine Resistance in Plasmodium falciparum in the Absence of Drug Pressure in the Ashanti Region of Ghana

2005 ◽  
Vol 49 (3) ◽  
pp. 1101-1105 ◽  
Author(s):  
Florian Marks ◽  
Jennifer Evans ◽  
Christian G. Meyer ◽  
Edmund N. Browne ◽  
Christa Flessner ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
High Frequency ◽  
Parasite Prevalence ◽  
Cross Resistance ◽  
Drug Pressure ◽  
Ashanti Region ◽  
High Prevalence ◽  
Resistance Markers ◽  
High Level ◽  
Weak Trend

ABSTRACT Markers of Plasmodium falciparum resistance to chloroquine (CQ) and pyrimethamine-sulfadoxine (PYR-SDX) are widespread in areas where malaria is endemic. In an area where the use PYR-SDX is negligible, the Ashanti Region of Ghana, West Africa, adult individuals were enrolled in an analysis of CQ- and PYR-SDX-associated molecular resistance markers in 2001 (n = 177) and 2003 (n = 180). Parasite prevalence, as assessed by PCR assays, were 56.5 and 48.8% in 2001 and 2003, respectively. A high frequency of CQ, PYR, and SDX resistance markers was observed, whereby, as a weak trend, the frequency was higher in 2003. The quintuple combination of three pfdhfr mutations and two pfdhps mutations has previously been recognized to be the most important determinant of PYR-SDX resistance. Approximately 60% of parasite carriers harbored fourfold mutated parasites, indicative of a considerable risk for a switch to high-level PYR-SDX resistance in an area where the rate of PYR-SDX use is low. Among the factors contributing to the high frequency of PYR-SDX resistance-associated mutations are background use of PYR-SDX, past use of PYR for malaria prophylaxis, cross-resistance of trimethoprim with PYR, and the sufficient biological fitness of resistant parasites in the absence of drug pressure.

scholarly journals High cases of submicroscopic Plasmodium falciparum infections in a suburban population of Lagos, Nigeria

2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Florence A. Umunnakwe ◽  
Emmanuel T. Idowu ◽  
Olusola Ajibaye ◽  
Blessed Etoketim ◽  
Samuel Akindele ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Large Scale ◽  
Quantitative Polymerase Chain Reaction ◽  
Age Groups ◽  
Malaria Diagnosis ◽  
School Age Children ◽  
Asymptomatic Malaria ◽  
High Prevalence ◽  
Study Population ◽  
Low Sensitivity

Abstract Background Asymptomatic malaria parasites are significant sources of infections for onward malaria transmission. Conventional tools for malaria diagnosis such as microscopy and rapid diagnostic test kits (RDT) have relatively low sensitivity, hence the need for alternative tools for active screening of such low-density infections. Methods This study tested var acidic terminal sequence-based (varATS) quantitative polymerase chain reaction (qPCR) for screening asymptomatic Plasmodium falciparum infections among dwellers of a sub-urban community in Lagos, Nigeria. Clinically healthy participants were screened for malaria using microscopy, RDT and varATS qPCR techniques. Participants were stratified into three age groups: 1–5, 6–14 and > 14 years old. Results Of the 316 participants screened for asymptomatic malaria infection, 78 (24.68%) were positive by microscopy, 99 (31.33%) were positive by RDT and 112 (35.44%) by varATS qPCR. Participants aged 6–14 years had the highest prevalence of asymptomatic malaria, with geometric means of ~ 116 parasites/µL and ~ 6689 parasites/µL as detected by microscopy and varATS, respectively. Conclusion This study has revealed high prevalence of asymptomatic malaria in the study population, with varATS detecting additional sub-microscopic infections. The highest concentration of asymptomatic malaria was observed among school-age children between 6 and 14 years old. A large-scale screening to identify other potential hotspots of asymptomatic parasites in the country is recommended.

scholarly journals Population structure and diversity of Plasmodium falciparum in children with asymptomatic malaria living in different ecological zones of Ghana

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Linda Eva Amoah ◽  
Zakaria Abukari ◽  
Maame Esi Dawson-Amoah ◽  
Cheikh Cambel Dieng ◽  
Eugenia Lo ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Plasmodium Falciparum ◽  
Population Structure ◽  
Coastal Zone ◽  
Primary Schools ◽  
Physical Distance ◽  
Asymptomatic Malaria ◽  
Coastal Zones ◽  
Forest Zone ◽  
Ecological Zones

Abstract Background Genetic diversity in Plasmodium falciparum populations can be used to describe the resilience and spatial distribution of the parasite in the midst of intensified intervention efforts. This study used microsatellite analysis to evaluate the genetic diversity and population dynamics of P. falciparum parasites circulating in three ecological zones of Ghana. Methods A total of 1168 afebrile children aged between 3 to 13 years were recruited from five (5) Primary schools in 3 different ecological zones (Sahel (Tamale and Kumbungu), Forest (Konongo) and Coastal (Ada and Dodowa)) of Ghana. Asymptomatic malaria parasite carriage was determined using microscopy and PCR, whilst fragment analysis of 6 microsatellite loci was used to determine the diversity and population structure of P. falciparum parasites. Results Out of the 1168 samples examined, 16.1 and 39.5% tested positive for P. falciparum by microscopy and nested PCR respectively. The genetic diversity of parasites in the 3 ecological zones was generally high, with an average heterozygosity (He) of 0.804, 0.787 and 0.608 the rainy (peak) season for the Sahel, Forest and Coastal zones respectively. The mean He for the dry (off-peak) season were 0.562, 0.693 and 0.610 for the Sahel, Forest and Coastal zones respectively. Parasites from the Forest zone were more closely related to those from the Sahel than from the Coastal zone, despite the Coastal zone being closer in physical distance to the Forest zone. The fixation indexes among study sites ranged from 0.049 to 0.112 during the rainy season and 0.112 to 0.348 during the dry season. Conclusion A large asymptomatic parasite reservoir was found in the school children during both rainy and dry seasons, especially those in the Forest and Sahel savannah zones where parasites were also found to be related compared to those from the Coastal zone. Further studies are recommended to understand why despite the roll out of several malaria interventions in Ghana, high transmission still persist.

scholarly journals Assessing Asymptomatic Malaria Carriage of Plasmodium falciparum and Non-falciparum Species in Children Resident in Nkolbisson, Yaoundé, Cameroon

Children ◽  
2021 ◽  
Vol 8 (11) ◽  
pp. 960
Author(s):  
Nji Mbuh Akindeh ◽  
Lesley Ngum Ngum ◽  
Peter Thelma Ngwa Niba ◽  
Innocent Mbulli Ali ◽  
Ornella Laetitia Oben Ayem ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Correct Diagnosis ◽  
Plasmodium Malariae ◽  
Cross Sectional Study ◽  
Malaria Prevalence ◽  
Asymptomatic Malaria ◽  
Cross Sectional ◽  
Predictive Values ◽  
Convenience Sampling ◽  
Polymerase Chain

Malaria is still a threat to public health as it remains the first endemic disease in the world. It is a pervasive parasitic disease in tropical and subtropical regions where asymptomatic malaria infection among humans serves as a significant reservoir for transmission. A rapid and correct diagnosis is considered to be an important strategy in the control of the disease especially in children, who are the most vulnerable group. This study assessed the prevalence of asymptomatic malaria in children at the Nkolbisson health area in Yaoundé, Cameroon. A cross-sectional study design and a convenience sampling plan were used. A total of 127 participants were recruited after informed and signed consent from parents and/or guardians. Blood samples were collected by finger-pricking and venipuncture from children aged 6 months to 10 years and then screened for asymptomatic parasitemia by a rapid diagnostic test (RDT), light microscopy (LM) staining with Giemsa and 18S rRNA polymerase chain reaction (PCR) for speciation. The data were analyzed using SPSS version 20 software. The study identified 85 children who were positive from the PCR, 95 positive from the RDT and 71 from the LM, revealing a malaria prevalence of 66.9%, 74.8% and 55.9%, respectively. The prevalence was not observed to be dependent on the sex and age group of the participants. Plasmodium falciparum was the predominant species followed by Plasmodium malariae and then Plasmodium ovale. The RDT and LM had the same sensitivity (90.6%) with a slight difference in their specificity (RDT: 57.1%; LM: 54.8%). The RDT also demonstrated higher positive and negative predictive values compared with those of the LM.

scholarly journals Age- and species-specific duration of infection in asymptomatic malaria infections in Papua New Guinea

Parasitology ◽  
2000 ◽  
Vol 121 (3) ◽  
pp. 247-256 ◽  
Author(s):  
M. C. BRUCE ◽  
C. A. DONNELLY ◽  
M. PACKER ◽  
M. LAGOG ◽  
N. GIBSON ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Papua New Guinea ◽  
Age Groups ◽  
New Guinea ◽  
Asymptomatic Malaria ◽  
Older Children ◽  
Statistical Assessment ◽  
Duration Of Infection ◽  
Species Specific ◽  
Frequent Sampling

The burden and duration of asymptomatic malaria infections were measured in residents of the malaria endemic village of Gonoa, Madang Province, Papua New Guinea. Plasmodium falciparum, P. vivax and P. malariae infections in people aged 4 years to adulthood were compared. Frequent sampling at 3-day intervals for up to 61 days allowed assessment of individual episodes of infection. Statistical assessment of P. falciparum detection revealed a periodicity consistent with synchronous replication of this species over periods up to 27 days. The duration of P. falciparum episodes was longer across all age groups than that of P. vivax and P. malariae. A trend for decreasing duration with age was also noted in data from each species. This was most prominent in P. falciparum infections: median duration in 4-year-olds was > 48 days compared with a median between 9 and 15 days in older children and adults. The results are consistent with the slow acquisition of immunity to antigenically diverse Plasmodium populations and suggest a faster rate of acquisition to P. vivax and P. malariae than to P. falciparum.

High Prevalence of Asymptomatic Malarial Anemia and Association with Early Conversion from Asymptomatic to Symptomatic Infection in a Plasmodium falciparum Hyperendemic Setting in Cameroon

2021 ◽  
Author(s):  
Balotin Fogang ◽  
Marie Fslorence Biabi ◽  
Rosette Megnekou ◽  
Franklin M. Maloba ◽  
Estelle Essangui ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Negative Impact ◽  
Female Gender ◽  
Asymptomatic Malaria ◽  
Nested Polymerase Chain Reaction ◽  
Symptomatic Infection ◽  
Malaria Parasitemia ◽  
High Prevalence ◽  
Prevalence Of Anemia ◽  
Malarial Anemia

Asymptomatic malarial parasitemia is highly prevalent in Plasmodium falciparum endemic areas and often associated with increased prevalence of mild to moderate anemia. The aim of this study was to assess the prevalence of anemia during asymptomatic malaria parasitemia and its interplay with persistent infection in highly exposed individuals. A household-based longitudinal survey was undertaken in a malaria hyperendemic area in Cameroon using multiplex nested polymerase chain reaction to detect plasmodial infections. Residents with P. falciparum asymptomatic parasitemia were monitored over a 3-week period with the aid of structured questionnaires and weekly measurements of axillary temperatures. Of the 353 individuals included (median age: 26 years, range 2–86 years, male/female sex ratio 0.9), 328 (92.9%) were positive for malaria parasitemia of whom 266 (81.1%) were asymptomatic carriers. The prevalence of anemia in the study population was 38.6%, of which 69.2% were asymptomatic. Multivariate analyses identified high parasitemia (> 327 parasites/µL) and female gender as associated risk factors of asymptomatic malarial anemia in the population. Furthermore, risk analyses revealed female gender and anemia at the time of enrolment as key predictors of early development of febrile illness (< 3 weeks post enrolment) among the asymptomatic individuals. Together, the data reveal an extremely high prevalence of asymptomatic malaria parasitemia and anemia in the study area, unveiling for the first time the association of asymptomatic malarial anemia with early clinical conversion from asymptomatic to symptomatic infection. Furthermore, these findings underscore the negative impact of asymptomatic malaria parasitemia on individual health, necessitating the development of appropriate control and preventive measures.

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