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.

scholarly journals Genetic diversity and dynamics of Plasmodium falciparum and P. vivax populations in multiply infected children with asymptomatic malaria infections in Papua New Guinea

Parasitology ◽  
2000 ◽  
Vol 121 (3) ◽  
pp. 257-272 ◽  
Author(s):  
M. C. BRUCE ◽  
M. R. GALINSKI ◽  
J. W. BARNWELL ◽  
C. A. DONNELLY ◽  
M. WALMSLEY ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Plasmodium Falciparum ◽  
Papua New Guinea ◽  
Median Duration ◽  
Antigenic Variation ◽  
Asymptomatic Malaria ◽  
Older Children ◽  
Asymptomatic Children ◽  
Episode Duration ◽  
Over Time

We describe the dynamics of co-infections of Plasmodium falciparum and P. vivax in 28 asymptomatic children by genotyping these species using the polymorphic loci Msp2 and Msp3α, respectively. The total number of Plasmodium spp. infections detected using 3 day sampling over 61 days varied between 1 and 14 (mean 6·6). The dynamics of P. falciparum and P. vivax genotypes varied greatly both within and amongst children. Periodicity in the detection of P. falciparum infections is consistent with the synchronous replication of individual genotypes. Replication synchrony of multiple co- infecting genotypes was not detected. In 4-year-old children P. falciparum genotype complexity was reduced and episodes lasted significantly longer (median duration > 60 days) when compared to children aged 5–14 years (median duration 9 days). P. vivax genotype complexity was not correlated with age but the episode duration was also longer for this species in 4-year-olds than in older children but was not as long as P. falciparum episodes. Recurrence of P. falciparum and P. vivax genotypes over weeks was observed. We interpret these major fluctuations in the density of genotypes over time as the result of the mechanism of antigenic variation thought to be present in these Plasmodium species.

scholarly journals The epidemiology and detectability of asymptomatic Plasmodium vivax and Plasmodium falciparum infections in low, moderate and high transmission settings in Ethiopia

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Elifaged Hailemeskel ◽  
Surafel K Tebeje ◽  
Sinknesh W. Behaksra ◽  
Girma Shumie ◽  
Getasew Shitaye ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Plasmodium Vivax ◽  
Age Groups ◽  
Diagnostic Tools ◽  
Asymptomatic Malaria ◽  
Rapid Diagnostics ◽  
Cross Sectional ◽  
Low Transmission ◽  
High Transmission ◽  
Study Sites

Abstract Background As countries move to malaria elimination, detecting and targeting asymptomatic malaria infections might be needed. Here, the epidemiology and detectability of asymptomatic Plasmodium falciparum and Plasmodium vivax infections were investigated in different transmission settings in Ethiopia. Method: A total of 1093 dried blood spot (DBS) samples were collected from afebrile and apparently healthy individuals across ten study sites in Ethiopia from 2016 to 2020. Of these, 862 were from community and 231 from school based cross-sectional surveys. Malaria infection status was determined by microscopy or rapid diagnostics tests (RDT) and 18S rRNA-based nested PCR (nPCR). The annual parasite index (API) was used to classify endemicity as low (API > 0 and < 5), moderate (API ≥ 5 and < 100) and high transmission (API ≥ 100) and detectability of infections was assessed in these settings. Results In community surveys, the overall prevalence of asymptomatic Plasmodium infections by microscopy/RDT, nPCR and all methods combined was 12.2% (105/860), 21.6% (183/846) and 24.1% (208/862), respectively. The proportion of nPCR positive infections that was detectable by microscopy/RDT was 48.7% (73/150) for P. falciparum and 4.6% (2/44) for P. vivax. Compared to low transmission settings, the likelihood of detecting infections by microscopy/RDT was increased in moderate (Adjusted odds ratio [AOR]: 3.4; 95% confidence interval [95% CI] 1.6–7.2, P = 0.002) and high endemic settings (AOR = 5.1; 95% CI 2.6–9.9, P < 0.001). After adjustment for site and correlation between observations from the same survey, the likelihood of detecting asymptomatic infections by microscopy/RDT (AOR per year increase = 0.95, 95% CI 0.9–1.0, P = 0.013) declined with age. Conclusions Conventional diagnostics missed nearly half of the asymptomatic Plasmodium reservoir detected by nPCR. The detectability of infections was particularly low in older age groups and low transmission settings. These findings highlight the need for sensitive diagnostic tools to detect the entire parasite reservoir and potential infection transmitters.

DRUG RESISTANT STRAINS OF PLASMODIUM FALCIPARUM IN PAPUA NEW GUINEA

The Lancet ◽  
1981 ◽  
Vol 317 (8216) ◽  
pp. 386
Author(s):  
Brian Darlow ◽  
Helena Vrbova ◽  
John Stace ◽  
Peter Heywood ◽  
Michael Alpers
Keyword(s):  
Plasmodium Falciparum ◽  
Papua New Guinea ◽  
New Guinea ◽  
Drug Resistant ◽  
Resistant Strains ◽  
Drug Resistant Strains

Role of pfmdr1 mutations on chloroquine resistance in Plasmodium falciparum isolates with pfcrt K76T from Papua New Guinea

Acta Tropica ◽  
2006 ◽  
Vol 98 (2) ◽  
pp. 137-144 ◽  
Author(s):  
Toshihiro Mita ◽  
Akira Kaneko ◽  
Francis Hombhanje ◽  
Ilomo Hwaihwanje ◽  
Nobuyuki Takahashi ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Papua New Guinea ◽  
New Guinea ◽  
Chloroquine Resistance

scholarly journals Increase in the proportion of Plasmodium falciparum with kelch13 C580Y mutation and decline in pfcrt and pfmdr1 mutant alleles in Papua New Guinea

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Naoko Yoshida ◽  
Masato Yamauchi ◽  
Ryosuke Morikawa ◽  
Francis Hombhanje ◽  
Toshihiro Mita
Keyword(s):  
Plasmodium Falciparum ◽  
Papua New Guinea ◽  
New Guinea ◽  
Therapeutic Effects ◽  
Cross Sectional Survey ◽  
Cross Sectional ◽  
In The Wild ◽  
Nationwide Surveillance ◽  
Greater Mekong Subregion ◽  
C580y Mutation

Abstract Background The C580Y mutation in the Plasmodium falciparum kelch13 gene is the most commonly observed variant in artemisinin-resistant isolates in the Greater Mekong Subregion (GMS). Until 2017, it had not been identified outside the GMS, except for Guyana/Amazonia. In 2017, three parasites carrying the C580Y mutation were identified in Papua New Guinea (PNG). As the C580Y allele rapidly spread in the GMS, there is concern that this mutant is now spreading in PNG. Methods In 2020, a cross-sectional survey was conducted at two clinics in Wewak, PNG. Symptomatic patients infected with P. falciparum were treated with artemether plus lumefantrine following a national treatment policy. Blood samples were obtained before treatment, and polymorphisms in kelch13, pfcrt, and pfmdr1 were determined. Parasite positivity was examined on day 3. The results were compared with those of previous studies conducted in 2002, 2003, and 2016–2018. Results A total of 94 patients were included in this analysis. The proportion of C580Y was significantly increased (2.2% in 2017, 5.7% in 2018, and 6.4% in 2020; p = 4.2 × 10–3). A significant upward trend was observed in the wild-type proportion for pfcrt (1.9% in 2016 to 46.7% in 2020; p = 8.9 × 10–16) and pfmdr1 (59.5% in 2016 to 91.4% in 2020; p = 2.3 × 10–6). Among 27 patients successfully followed on day 3, including three with C580Y infections, none showed positive parasitaemia. Conclusions Under the conditions of significant increases in pfcrt K76 and pfmdr1 N86 alleles in PNG, the increase in kelch13 C580Y mutants may be a warning indicator of the emergence of parasites resistant to the currently used first-line treatment regimen of artemether plus lumefantrine. Therefore, nationwide surveillance of molecular markers for drug resistance and assessment of its therapeutic effects are important.

scholarly journals The epidemiology of Plasmodium falciparum and Plasmodium vivax in East Sepik Province, Papua New Guinea, pre- and post-implementation of national malaria control efforts

2020 ◽  
Vol 19 (1) ◽  
Author(s):  
Johanna H. Kattenberg ◽  
Dulcie L. Gumal ◽  
Maria Ome-Kaius ◽  
Benson Kiniboro ◽  
Matthew Philip ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Plasmodium Vivax ◽  
Papua New Guinea ◽  
Malaria Control ◽  
New Guinea
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