Prevalence of intermittent preventive treatment with sulphadoxine-pyrimethamine (IPTp-SP) use during pregnancy and other associated factors in Sekondi-Takoradi, Ghana

Background: Intermittent preventive treatment in pregnancy (IPTp) with sulphadoxine-pyrimethamine (SP) has been adopted as policy by most countries in sub-Saharan Africa. This cross-sectional study assessed the prevalence of IPTp-SP usage for prevention of malaria among pregnant women as well as evaluated factors associated with IPTp-SP use during pregnancy in Sekondi-Takoradi region of Ghana.Methods: Pregnant women attending their antenatal-care with either clinical/ultrasound evidence of pregnancy were recruited. Venous blood was screened for malaria using RAPID response antibody kit and Giemsa staining. Haemoglobin estimations were done by cyanmethemoglobin method while Human Immunodeficiency Virus (HIV) screening was performed by the national diagnostic algorithm of two rapid antibody test and western blot confirmation.Results: Of the 754 consented pregnant women interviewed in this study, 57.8% had received IPTp-SP while 42.2% had not at their first contact with the study personnel. Furthermore, 18.6% (81/436) of those that received IPTp-SP were malaria positive while 81.4% (355/436) were malaria negative. The results also indicated that 47.7% (51/107) of the pregnant women in their third trimester who were meant to have received at least two-doses of SP had received ≥2 doses while 35.5% (38/107) had received 1 dose. In multivariable logistic regression analysis, pregnant women in their third trimester who received ≥2 doses of SP showed decreased likelihoods of malaria (adjusted OR, 0.042; 95% CI, 0.003-0.51; P = 0.013).Conclusion: IPTp-SP usage among pregnant women in Sekondi-Takoradi reduces malaria and its use for malaria prevention should be strengthened with proper dosage completion and coverage.Keywords: Malaria in pregnancy, IPTp-SP, anaemia, Ghan

Differences in Fcgamma receptor IIa genotypes and IgG subclass pattern of anti-malarial antibodies between sympatric ethnic groups in Mali

<p>Abstract</p> <p>Background</p> <p>The Ig Fc receptor family is an important link between the humoral and cellular immune systems. The association of a dimorphism in amino acid 131 (R/H) of the FcγRIIa with malaria severity, the R-allele being associated with a milder disease outcome, led to the investigation of the possible impact of this polymorphism in the interethnic difference in malaria susceptibility seen between the Fulani and Dogon in Mali.</p> <p>Methods</p> <p>Plasma from individuals from Mali (164 Fulani and 164 Dogon) were analysed for malaria-reactive and total IgG subclass antibodies using ELISA, and the same individuals were also genotyped for the FcγRIIa R131H polymorphism using RFLP-PCR. Statistical analyses of the IgG subclass levels were done by unpaired t-test and ANOVA, and genotype differences were tested by χ²-test.</p> <p>Results</p> <p>While the two ethnic groups showed a similar frequency of the FcγRIIa 131 R/H heterozygote genotype, 131R/R dominated over the 131 H/H genotype in the Dogon whereas the Fulani presented a similar frequency of the two homozygote genotypes. The two alleles were evenly distributed in the Fulani, while the Dogon were clearly biased towards the R-allele. The Fulani showed higher levels of anti-malarial IgG1, -2 and -3 antibodies, with a higher proportion of IgG2, than the Dogon. In the Fulani, H-allele carriers had higher anti-malarial IgG2 levels than R/R homozygotes, while in the Dogon, the R-allele carriers showed the higher IgG2 levels. For anti-malarial IgG3, the R-allele carriers in the Fulani had higher levels than the H/H homozygotes.</p> <p>Conclusion</p> <p>Taken together, the results showed marked interethnic differences in FcγRIIa R131H genotypes. Furthermore, the results indicate that the FcγRIIa R131H genotype may influence the IgG subclass responses related to protection against malaria, and that IgG2 may be of importance in this context.</p

Prevalence of intermittent preventive treatment with sulphadoxine-pyrimethamine (IPTp-SP) use during pregnancy and other associated factors in Sekondi-Takoradi, Ghana

Background: Intermittent preventive treatment in pregnancy (IPTp) with sulphadoxine-pyrimethamine (SP) has been adopted as policy by most countries in sub-Saharan Africa. This cross-sectional study assessed the prevalence of IPTp-SP usage for prevention of malaria among pregnant women as well as evaluated factors associated with IPTp-SP use during pregnancy in Sekondi-Takoradi region of Ghana. Methods: Pregnant women attending their antenatal-care with either clinical/ultrasound evidence of pregnancy were recruited. Venous blood was screened for malaria using RAPID response antibody kit and Giemsa staining. Haemoglobin estimations were done by cyanmethemoglobin method while Human Immunodeficiency Virus (HIV) screening was performed by the national diagnostic algorithm of two rapid antibody test and western blot confirmation. Results: Of the 754 consented pregnant women interviewed in this study, 57.8% had received IPTp-SP while 42.2% had not at their first contact with the study personnel. Furthermore, 18.6% (81/436) of those that received IPTp-SP were malaria positive while 81.4% (355/436) were malaria negative. The results also indicated that 47.7% (51/107) of the pregnant women in their third trimester who were meant to have received at least two-doses of SP had received 652 doses while 35.5% (38/107) had received 1 dose. In multivariable logistic regression analysis, pregnant women in their third trimester who received 652 doses of SP showed decreased likelihoods of malaria (adjusted OR, 0.042; 95% CI, 0.003-0.51; P = 0.013). Conclusion: IPTp-SP usage among pregnant women in Sekondi-Takoradi reduces malaria and its use for malaria prevention should be strengthened with proper dosage completion and coverage

Genetic diversity of Plasmodium falciparum parasite by microsatellite markers after scale-up of insecticide-treated bed nets in western Kenya

Background: An initial study of genetic diversity of Plasmodium falciparum in Asembo, western Kenya showed that the parasite maintained overall genetic stability 5 years after insecticide-treated bed net (ITN) introduction in 1997. This study investigates further the genetic diversity of P. falciparum 10 years after initial ITN introduction in the same study area and compares this with two other neighbouring areas, where ITNs were introduced in 1998 (Gem) and 2004 (Karemo). Methods: From a cross-sectional survey conducted in 2007, 235 smear-positive blood samples collected from children ≤15-year-old in the original study area and two comparison areas were genotyped employing eight neutral microsatellites. Differences in multiple infections, allele frequency, parasite genetic diversity and parasite population structure between the three areas were assessed. Further, molecular data reported previously (1996 and 2001) were compared to the 2007 results in the original study area Asembo. Results: Overall proportion of multiple infections (M A ) declined with time in the original study area Asembo (from 95.9 %-2001 to 87.7 %-2007). In the neighbouring areas, M A was lower in the site where ITNs were introduced in 1998 (Gem 83.7 %) compared to where they were introduced in 2004 (Karemo 96.7 %) in 2007. Overall mean allele count (M AC ~ 2.65) and overall unbiased heterozygosity (H e ~ 0.77) remained unchanged in 1996, 2001 and 2007 in Asembo and was the same level across the two neighbouring areas in 2007. Overall parasite population differentiation remained low over time and in the three areas at F ST < 0.04. Both pairwise and multilocus linkage disequilibrium showed limited to no significant association between alleles in Asembo (1996, 2001 and 2007) and between three areas. Conclusions: This study showed the P. falciparum high genetic diversity and parasite population resilience on samples collected 10 years apart and in different areas in western Kenya. The results highlight the need for long-term molecular monitoring after implementation and use of combined and intensive prevention and intervention measures in the region

Dynamics of IgG antibody response against Plasmodium antigens among Nigerian infants and young children

BackgroundPlasmodium falciparum malaria is a leading cause of child mortality in Nigeria. Neonates are born with maternal antibodies from placental transfer which may protect against malaria infection in the first months of life. The IgG dynamics of the transition from passively transferred antimalarial antibodies to actively acquired IgG from natural exposure have not been well elucidated.MethodsBlood samples collected during a 2018 Nigeria nationwide HIV/AIDS household survey were available for 9,443 children under 5 years of age, with a subset of infants under 2 months of age having maternal samples available (n=41). Samples were assayed for the P. falciparum HRP2 antigen and anti-malarial IgG antibodies. LOESS regression examined the dynamics in IgG response in the first 5 years of life. Correlation with maternal IgG levels was assessed for mother/child pairs.ResultsConsistent decreases were observed in median IgG levels against all Plasmodium spp. antigen targets for the first months of life. At a population level, P. falciparum apical membrane antigen-1 (AMA1) and merozoite surface protein-1 19kD (PfMSP1) IgG decreased during the first 12 months of life before reaching a nadir, whereas IgGs to other targets only declined for the first 4 months of life. Seropositivity showed a similar decline with the lowest seropositivity against AMA1 and PfMSP1 at 10-12 months, though remaining above 50% during the first 2 years of life in higher transmission areas. No protective association was observed between IgG positivity and P. falciparum infection in infants. Maternal antibody levels showed a strong positive correlation with infant antibody levels for all P. falciparum antigens from birth to 2 months of age, but this correlation was lost by 6 months of age.DiscussionMaternally transferred anti-malarial IgG antibodies rapidly decline during the first 6 months of life, with variations among specific antigens and malaria transmission intensity. From 3-23 months of age, there was a wide range in IgG levels for the blood-stage antigens indicating high individual variation in antibody production as children are infected with malaria. Non-falciparum species-specific antigens showed similar patterns in waning immunity and correlation with paired mother’s IgG levels compared to P. falciparum antigens

Antigen-specific influence of GM/KM allotypes on IgG isotypes and association of GM allotypes with susceptibility to Plasmodium falciparum malaria

<p>Abstract</p> <p>Background</p> <p><it>Plasmodium falciparum </it>malaria is a complex disease in which genetic and environmental factors influence susceptibility. IgG isotypes are in part genetically controlled, and GM/KM allotypes are believed to be involved in this control.</p> <p>Methods</p> <p>In this study, 216 individuals from Daraweesh, an area of seasonal malaria transmission in Sudan, were followed for nine years for malaria infection. Total IgG and IgG isotypes against four malaria antigens, MSP2-3D7, MSP2-FC27, AMA1, and Pf332-C231 were measured in plasma obtained from the cohort at the end of the study, during the dry malaria-free period. The GM/KM allotypes of the donors were determined.</p> <p>Results</p> <p>The GM 1,17 5,13,14,6 phenotype was associated with a higher incidence of malaria compared with the non-1,17 5,13,14,6 phenotypes (P = 0.037). Paradoxically, the carriers of the GM 1,17 5,13,14,6 phenotype had significantly higher baseline levels of total IgG and non-cytophilic IgG isotypes as compared to non-carriers. The KM allotypes influence on IgG isotypes level was limited. Finally, the differences in the baseline concentrations of total IgG and IgG isotypes between the different GK/KM phenotype carriers were antigen-dependent.</p> <p>Discussion</p> <p>The results show that GM but not KM allotypes appeared to influence host susceptibility to uncomplicated malaria as well as the antibody profile of the donors, and the carriers of the GM 1,17 5,13,14,6 phenotype were the most susceptible</p> <p>Conclusions</p> <p>The GM allotypes have significant influence on susceptibility to uncomplicated <it>P. falciparum </it>malaria and antigen-dependent influence on total IgG and IgG subclasses.</p

Seroprevalence of SARS-CoV-2 in four states of Nigeria in October 2020: A population-based household survey

The observed epidemiology of SARS-CoV-2 in sub-Saharan Africa has varied greatly from that in Europe and the United States, with much lower reported incidence. Population-based studies are needed to estimate true cumulative incidence of SARS-CoV-2 to inform public health interventions. This study estimated SARS-CoV-2 seroprevalence in four selected states in Nigeria in October 2020. We implemented a two-stage cluster sample household survey in four Nigerian states (Enugu, Gombe, Lagos, and Nasarawa) to estimate age-stratified prevalence of SARS-CoV-2 antibodies. All individuals in sampled households were eligible for interview, blood draw, and nasal/oropharyngeal swab collection. We additionally tested participants for current/recent malaria infection. Seroprevalence estimates were calculated accounting for the complex survey design. Across all four states, 10,629 (96·5%) of 11,015 interviewed individuals provided blood samples. The seroprevalence of SARS-CoV-2 antibodies was 25·2% (95% CI 21·8–28·6) in Enugu State, 9·3% (95% CI 7·0–11·5) in Gombe State, 23·3% (95% CI 20·5–26·4) in Lagos State, and 18·0% (95% CI 14·4–21·6) in Nasarawa State. Prevalence of current/recent malaria infection ranged from 2·8% in Lagos to 45·8% in Gombe and was not significantly related to SARS-CoV-2 seroprevalence. The prevalence of active SARS-CoV-2 infection in the four states during the survey period was 0·2% (95% CI 0·1–0·4). Approximately eight months after the first reported COVID-19 case in Nigeria, seroprevalence indicated infection levels 194 times higher than the 24,198 officially reported COVID-19 cases across the four states; however, most of the population remained susceptible to COVID-19 in October 2020

Contribution of PEPFAR-Supported HIV and TB Molecular Diagnostic Networks to COVID-19 Testing Preparedness in 16 Countries.

The US President's Emergency Plan for AIDS Relief (PEPFAR) supports molecular HIV and tuberculosis diagnostic networks and information management systems in low- and middle-income countries. We describe how national programs leveraged these PEPFAR-supported laboratory resources for SARS-CoV-2 testing during the COVID-19 pandemic. We sent a spreadsheet template consisting of 46 indicators for assessing the use of PEPFAR-supported diagnostic networks for COVID-19 pandemic response activities during April 1, 2020, to March 31, 2021, to 27 PEPFAR-supported countries or regions. A total of 109 PEPFAR-supported centralized HIV viral load and early infant diagnosis laboratories and 138 decentralized HIV and TB sites reported performing SARS-CoV-2 testing in 16 countries. Together, these sites contributed to >3.4 million SARS-CoV-2 tests during the 1-year period. Our findings illustrate that PEPFAR-supported diagnostic networks provided a wide range of resources to respond to emergency COVID-19 diagnostic testing in 16 low- and middle-income countries