scholarly journals Spatial cluster analysis of Plasmodium vivax and P. malariae exposure using serological data among Haitian school children sampled between 2014 and 2016

2022 ◽  
Vol 16 (1) ◽  
pp. e0010049
Author(s):  
Adan Oviedo ◽  
Camelia Herman ◽  
Alaine Knipes ◽  
Caitlin M. Worrell ◽  
LeAnne M. Fox ◽  
...  
Keyword(s):  
Surface Protein ◽  
Merozoite Surface Protein ◽  
Malaria Prevalence ◽  
Scan Statistics ◽  
Spatial Scan Statistic ◽  
School Based ◽  
Endemic Malaria ◽  
Malaria Species ◽  
Spatial Scan ◽  
Serological Data

Background Estimation of malaria prevalence in very low transmission settings is difficult by even the most advanced diagnostic tests. Antibodies against malaria antigens provide an indicator of active or past exposure to these parasites. The prominent malaria species within Haiti is Plasmodium falciparum, but P. vivax and P. malariae infections are also known to be endemic. Methodology/Principal findings From 2014–2016, 28,681 Haitian children were enrolled in school-based serosurveys and were asked to provide a blood sample for detection of antibodies against multiple infectious diseases. IgG against the P. falciparum, P. vivax, and P. malariae merozoite surface protein 19kD subunit (MSP119) antigens was detected by a multiplex bead assay (MBA). A subset of samples was also tested for Plasmodium DNA by PCR assays, and for Plasmodium antigens by a multiplex antigen detection assay. Geospatial clustering of high seroprevalence areas for P. vivax and P. malariae antigens was assessed by both Ripley’s K-function and Kulldorff’s spatial scan statistic. Of 21,719 children enrolled in 680 schools in Haiti who provided samples to assay for IgG against PmMSP119, 278 (1.27%) were seropositive. Of 24,559 children enrolled in 788 schools providing samples for PvMSP119 serology, 113 (0.46%) were seropositive. Two significant clusters of seropositivity were identified throughout the country for P. malariae exposure, and two identified for P. vivax. No samples were found to be positive for Plasmodium DNA or antigens. Conclusions/Significance From school-based surveys conducted from 2014 to 2016, very few Haitian children had evidence of exposure to P. vivax or P. malariae, with no children testing positive for active infection. Spatial scan statistics identified non-overlapping areas of the country with higher seroprevalence for these two malarias. Serological data provides useful information of exposure to very low endemic malaria species in a population that is unlikely to present to clinics with symptomatic infections.

scholarly journals Genetic diversity of Plasmodium falciparum in Grande Comore Island

2020 ◽  
Author(s):  
Nasserdine Papa Mze ◽  
Hervé Bogreau ◽  
Cyrille K. Diedhiou ◽  
Vendela Herdell ◽  
Silai Rahamatou ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Plasmodium Falciparum ◽  
Public Health Problem ◽  
Surface Protein ◽  
Merozoite Surface Protein ◽  
Malaria Prevalence ◽  
Nucleotide Polymorphism ◽  
Single Nucleotide ◽  
Grande Comore ◽  
Union Of The Comoros

Abstract Background Despite several control interventions resulting in a considerable decrease in malaria prevalence in the Union of the Comoros, the disease remains a public health problem with high transmission in Grand Comore compared to neighboring islands. In this country, only a few studies investigating the genetic diversity of Plasmodium falciparum have been performed so far. For this reason, this study aims to examine the genetic diversity of P. falciparum by studying samples collected in Grande Comore in 2012 and 2013, using merozoite surface protein 1 (msp1), merozoite surface protein 2 (msp2) and single nucleotide polymorphism (SNP) genetic markers.Methods A total of 151 positive rapid diagnostic test (RDT) samples from Grande Comore were used to extract parasite DNA. Allelic families K1, Mad20 and RO33 of the msp1 gene as well as allelic families IC3D7 and FC37 of the msp2 gene were determined by using nested PCR. Additionally, 50 out of 151 samples were genotyped to study 24 SNPs by using high resolution melting (HRM).Results Two allelic families were predominant, the K1 family of msp1 gene (55%) and the FC27 family of msp2 gene (47.4%). Among 50 samples genotyped for 24 SNPs, 42 (84%) yielded

scholarly journals Spatial Scan Statistics Adjusted for Multiple Clusters

2010 ◽  
Vol 2010 ◽  
pp. 1-11 ◽  
Author(s):  
Zhenkui Zhang ◽  
Renato Assunção ◽  
Martin Kulldorff
Keyword(s):  
Error Probability ◽  
Type I Error ◽  
Statistical Significance ◽  
Scan Statistics ◽  
Type I ◽  
Spatial Scan Statistic ◽  
Scan Statistic ◽  
Study Region ◽  
Type I Error Probability ◽  
Spatial Scan

The spatial scan statistic is one of the main epidemiological tools to test for the presence of disease clusters in a geographical region. While the statistical significance of the most likely cluster is correctly assessed using the model assumptions, secondary clusters tend to have conservatively highP-values. In this paper, we propose a sequential version of the spatial scan statistic to adjust for the presence of other clusters in the study region. The procedure removes the effect due to the more likely clusters on less significant clusters by sequential deletion of the previously detected clusters. Using the Northeastern United States geography and population in a simulation study, we calculated the type I error probability and the power of this sequential test under different alternative models concerning the locations and sizes of the true clusters. The results show that the type I error probability of our method is close to the nominalαlevel and that for secondary clusters its power is higher than the standard unadjusted scan statistic.

Spatial scan statistics can be dangerous

2021 ◽  
Vol 30 (1) ◽  
pp. 75-86
Author(s):  
Toshiro Tango
Keyword(s):  
Disease Surveillance ◽  
Epidemiological Studies ◽  
Scan Statistics ◽  
Mortality Data ◽  
Spatial Scan Statistic ◽  
Scan Statistic ◽  
Spatial Scan Statistics ◽  
Restricted Likelihood ◽  
Risk Of Disease ◽  
Spatial Scan

Spatial scan statistics are widely used tools for the detection of disease clusters. Especially, the circular spatial scan statistic proposed by Kulldorff along with SaTScan software has been used in a wide variety of epidemiological studies and disease surveillance. However, as it cannot detect non-circular, irregularly shaped clusters, many authors have proposed non-circular spatial scan statistics. Above all, the flexible spatial scan statistic proposed by Tango and Takahashi along with FleXScan software has also been used. However, it does not seem to be well recognized that these spatial scan statistics, especially SaTScan, tend to detect the most likely cluster, much larger than the true cluster by absorbing neighboring regions with nonelevated risk of disease occurrence. Therefore, if researchers reported the detected most likely cluster as they are, it might lead to a criticism to them due to the fact that some regions with nonelevated risk are included in the detected most likely cluster. In this paper, to avoid detecting such undesirable and misleading clusters which might cause a social concern, we shall propose the use of the restricted likelihood ratio proposed by Tango and illustrate the procedure with two kinds of mortality data in Japan.

scholarly journals Analisis Spasial Persebaran Dan Pemetaan Kerawanan Daerah Titik Panas Di Kalimantan Timur Menggunakan Spatial Pattern Analysis Dan Flexibly Shaped Spatial Scan Statistic

2020 ◽  
Vol 1 (1) ◽  
pp. 20
Author(s):  
Tiara Nur Hikmaulida ◽  
Memi Nor Hayati ◽  
Sri Wahyuningsih
Keyword(s):  
Spatial Autocorrelation ◽  
Distribution Pattern ◽  
Spatial Data ◽  
Fire Hazard ◽  
Scan Statistics ◽  
Local Analysis ◽  
Spatial Pattern Analysis ◽  
Spatial Scan Statistic ◽  
East Kalimantan ◽  
Spatial Scan

The statistical method used to analyze spatial data and spatial statistics. The case study in this study is the average number of hotspots in East Kalimantan by Regency / City in 2016-2018. This study aims to analyze the presence or absence of spatial autocorrelation in the data on the number of hotspots, determine the distribution pattern of hotspots, as well as determine the level of vulnerability of potential areas for forest and land fires in East Kalimantan by Regency / City in 2016-2018.  The method used to analyze spatial autocorrelation globally and determine the distribution patterns is the Moran Index. Local Indicator of Spatial Autocorrelation (LISA) to analyze spatial autocorrelation locally. Spatial autocorrelation analysis results globally using the Moran Index with α = 25% shows that there is a spatial autocorrelation in the average number of hotspots in East Kalimantan in 2016-2018. The distribution pattern of hotspots in East Kalimantan is the pattern of spread which shows that in 2016-2018 the hotspots spread in each district / city of East Kalimantan. Meanwhile, the results of the local analysis using LISA showed that there were spatial autocorrelations in several districts / cities in East Kalimantan. The method used to determine the level of vulnerability of potential forest and land fires is Flexibly Shaped Spatial Scan Statistics and LISA. The results showed that the regencies / cities included in the category of forest and land fire hazard were Samarinda City, Bontang City, Kutai Kartanegara District and East Kutai.

scholarly journals Genetic diversity of Plasmodium falciparum in Grande Comore Island

2020 ◽  
Author(s):  
Nasserdine Papa Mze ◽  
Hervé Bogreau ◽  
Cyrille K. Diedhiou ◽  
Vendela Herdell ◽  
Silai Rahamatou ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Plasmodium Falciparum ◽  
Public Health Problem ◽  
Surface Protein ◽  
Merozoite Surface Protein ◽  
Malaria Prevalence ◽  
Grande Comore ◽  
Union Of The Comoros ◽  
Msp2 Gene ◽  
Msp1 Gene

Abstract Background Despite several control interventions resulting in a considerable decrease in malaria prevalence in the Union of the Comoros, the disease remains a public health problem with high transmission in Grand Comore compared to neighboring islands. In this country, only a few studies investigating the genetic diversity of Plasmodium falciparum have been performed so far. For this reason, this study aims to examine the genetic diversity of P. falciparum by studying samples collected in Grande Comore in 2012 and 2013, using merozoite surface protein 1 ( msp1 ), merozoite surface protein 2 ( msp2 ) and single nucleotide polymorphism (SNP) genetic markers. Methods A total of 151 positive rapid diagnostic test (RDT) samples from Grande Comore were used to extract parasite DNA. Allelic families K1, Mad20 and RO33 of the msp1 gene as well as allelic families IC3D7 and FC37 of the msp2 gene were determined by using nested PCR. Additionally, 50 out of 151 samples were genotyped to study 24 SNPs by using high resolution melting (HRM). Results Two allelic families were predominant, the K1 family of msp1 gene (55%) and the FC27 family of msp2 gene (47.4%). Among 50 samples genotyped for 24 SNPs, 42 (84%) yielded interpretable results. Out of these isolates, 36 (85%) were genetically unique and 6 (15%) grouped into two clusters. The genetic diversity of Plasmodium falciparum calculated from msp gene ( msp1 and msp 2) and SNPs was 0.82 and 0.6 respectively. Conclusion In summary, a large genetic diversity of P. falciparum was observed in Grande Comore. This may favor persistence of malaria, and might be one of the reasons for the high malaria transmission compared to neighboring islands. Further surveillance of P. falciparum isolates, mainly through environmental management / vector control, is warranted until complete elimination is attained.

scholarly journals PvMSP8 as a Novel Plasmodium vivax Malaria Sero-Marker for the Peruvian Amazon

Pathogens ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 282
Author(s):  
Elizabeth Villasis ◽  
Katherine Garro ◽  
Angel Rosas-Aguirre ◽  
Pamela Rodriguez ◽  
Jason Rosado ◽  
...  
Keyword(s):  
Plasmodium Vivax ◽  
Area Under The Curve ◽  
Surface Protein ◽  
Merozoite Surface Protein ◽  
Population Based ◽  
Peruvian Amazon ◽  
Cross Sectional Survey ◽  
Cross Sectional ◽  
Malaria Exposure ◽  
Plasmodium Vivax Malaria

The measurement of recent malaria exposure can support malaria control efforts. This study evaluated serological responses to an in-house Plasmodium vivax Merozoite Surface Protein 8 (PvMSP8) expressed in a Baculovirus system as sero-marker of recent exposure to P. vivax (Pv) in the Peruvian Amazon. In a first evaluation, IgGs against PvMSP8 and PvMSP10 proteins were measured by Luminex in a cohort of 422 Amazonian individuals with known history of Pv exposure (monthly data of infection status by qPCR and/or microscopy over five months). Both serological responses were able to discriminate between exposed and non-exposed individuals in a good manner, with slightly higher performance of anti-PvMSP10 IgGs (area under the curve AUC = 0.78 [95% CI = 0.72–0.83]) than anti-PvMSP8 IgGs (AUC = 0.72 [95% CI = 0.67–0.78]) (p = 0.01). In a second evaluation, the analysis by ELISA of 1251 plasma samples, collected during a population-based cross-sectional survey, confirmed the good performance of anti-PvMSP8 IgGs for discriminating between individuals with Pv infection at the time of survey and/or with antecedent of Pv in the past month (AUC = 0.79 [95% CI = 0.74–0.83]). Anti-PvMSP8 IgG antibodies can be considered as a good biomarker of recent Pv exposure in low-moderate transmission settings of the Peruvian Amazon.

scholarly journals Allelic diversity of merozoite surface protein genes (msp1 and msp2) and clinical manifestations of Plasmodium falciparum malaria cases in Aceh, Indonesia

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Kurnia Fitri Jamil ◽  
Nandha Rizki Pratama ◽  
Sylvia Sance Marantina ◽  
Harapan Harapan ◽  
Muhammad Riza Kurniawan ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Liver Function ◽  
Severe Malaria ◽  
Clinical Manifestation ◽  
Allelic Diversity ◽  
Surface Protein ◽  
Merozoite Surface Protein ◽  
Malaria Control Programme ◽  
Co Morbidity ◽  
Aceh Province

Abstract Background The malaria control programme in Indonesia has successfully brought down malaria incidence in many parts in Indonesia, including Aceh Province. Clinical manifestation of reported malaria cases in Aceh varied widely from asymptomatic, mild uncomplicated to severe and fatal complications. The present study aims to explore the allelic diversity of merozoite surface protein 1 gene (msp1) and msp2 among the Plasmodium falciparum isolates in Aceh Province and to determine their potential correlation with the severity of malaria clinical manifestation. Methods Screening of over 500 malaria cases admitted to the hospitals in 11 districts hospital within Aceh Province during 2013–2015, identified 90 cases of P. falciparum mono-infection without any co-morbidity. The subjects were clinically phenotyped and parasite DNA was extracted and polymerase chain reaction (PCR) amplified for the msp1 and msp2 allelic subfamilies. Results Analysis of clinical manifestation revealed that fever-chill is the most frequent symptom. Based on WHO criteria showed 19 cases were classified as severe and 71 as mild malaria. Analysis of msp1 gene revealed the presence of K1 allele subfamily in 34 subjects, MAD20 in 42 subjects, RO33 in 1 subject, and mixed allelic of K1 + MAD20 in 5 subjects, K1 + RO33 in 4 subjects, and MAD20 + RO33 in 4 subjects. Analysis of msp2 gene revealed 34 subjects carried the FC27 allelic subfamily, 37 subjects carried the 3D7 and 19 subjects carried the mixed FC27 + 3D7. Analysis of multiplicity of infection revealed that msp1 alleles is slightly higher than msp2 with the mean of MOI were 2.69 and 2.27, respectively. Statistical analysis to determine the association between each clinical manifestation and msp1 and msp2 alleles revealed that liver function abnormal value was associated with the msp2 mixed alleles (odds ratio (OR):0.13; 95%CI: 0.03–0.53). Mixed msp1 of K1 + RO33 was associated with severe malaria (OR: 28.50; 95%CI: 1.59–1532.30). Conclusion This study found a strong association between severe malaria in Aceh with subjects carrying the msp1 mixed alleles of K1 and RO33. The liver function abnormal value associated with the msp2 mixed allelic subfamilies. Further study in different geographic areas is recommended.

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