Sero-prevalence study of parasitic infections among HIV positive and Negative patients in Lagos, Nigeria

Background: Diseases caused by opportunistic pathogens are the major clinical signs of HIV infected and AIDS patients with parasitic infection being part of the common causes of morbidity and mortality.Objectives: This was a cross-sectional study to determine the sero prevalence of serum antibodies to three parasitic infections namely Entamoeba histolytica, Schistosoma sp. and Toxoplasma gondii, which are opportunistic infections among HIV/AIDS patients.Methods: One thousand and eighty patients that attended three healthcare institutions in Lagos were recruited for the study through convenience sampling method. Venous blood was collected from the recruited patients and screened for HIV infection as well as the presence of serum antibodies to three parasitic infections. All positive sera samples were confirmed for HIV infection.Result: The results revealed that 65/1080 (6%) of the recruited patients were HIV sero-positive. In addition, 5/65 (7.7%) of the HIV positive patients had E. histolytica co-infection, 1/65 (1.5%) had Schistosoma sp. co-infection while 2/65 (3.1%) had T. gondii co infection. The results also indicated that the proportion of patients with E. histolytica was significantly higher among HIV sero-positive patients than the sero-negative patients (P = 0.031).Conclusion: The study showed the opportunistic potential of the three parasitic infections among HIV/AIDS patients in the study area.Keywords: HIV, AIDS, Seropositive, Seronegative, Toxoplasma gondii, Entamoeba histolytica, Schistosoma haematobiu

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

Validation of Commercial SARS-CoV-2 Immunoassays in a Nigerian Population

Validated assays are essential for reliable serosurveys; however, most SARS-CoV-2 immunoassays have been validated using specimens from China, Europe, or U.S. populations. We evaluated the performance of five commercial SARS-CoV-2 immunoassays to inform their use in serosurveys in Nigeria. Four semiquantitative enzyme-linked immunosorbent assays (ELISAs) (Euroimmun anti-SARS-CoV-2 nucleocapsid protein [NCP] immunoglobulin G [IgG], Euroimmun spike SARS-CoV-2 IgG, Mologic Omega COVID-19 IgG, Bio-Rad Platelia SARS-CoV-2 Total Ab) and one chemiluminescent microparticle immunoassay (Abbott Architect SARS-CoV-2 IgG) were evaluated. We estimated the analytical performance characteristics using plasma from 100 SARS-CoV-2 PCR-positive patients from varied time points post-PCR confirmation and 100 prepandemic samples (50 HIV positive and 50 hepatitis B positive). The Bio-Rad assay failed the manufacturer-specified validation steps. The Euroimmun NCP, Euroimmun spike, and Mologic assays had sensitivities of 73.7%, 74.4%, and 76.9%, respectively, on samples taken 15 to 58 days after PCR confirmation and specificities of 97%, 100%, and 83.8%, respectively. The Abbott assay had 71.3% sensitivity and 100% specificity on the same panel. Parallel or serial algorithms combining two tests did not substantially improve the sensitivity or specificity. Our results showed lower sensitivity and, for one immunoassay, lower specificity compared to the manufacturers' results and other reported validations. Seroprevalence estimates using these assays might need to be interpreted with caution in Nigeria and similar settings. These findings highlight the importance of in-country validations of SARS-CoV-2 serological assays prior to use to ensure that accurate results are available for public health decision-making to control the COVID-19 pandemic in Africa. IMPORTANCE This study used positive and negative sample panels from Nigeria to test the performance of several commercially available SARS-CoV-2 serological assays. Using these prepandemic and SARS-CoV-2-positive samples, we found much lower levels of sensitivity in four commercially available assays than most assay manufacturer reports and independent evaluations. The use of these assays with suboptimal sensitivity and specificity in Nigeria or countries with population exposure to similar endemic pathogens could lead to a biased estimate of the seroprevalence, over- or underestimating the true disease prevalence, and limit efforts to stop the spread of SARS-CoV-2. It is important to conduct in-country validations of serological SARS-CoV-2 assays prior to their widespread use, especially in countries with limited representation in published assay validations

Non-falciparum malaria infection and IgG seroprevalence among children under 15 years in Nigeria, 2018.

Plasmodium falciparum (Pf) is the dominant malaria parasite in Nigeria though P. vivax (Pv), P. ovale (Po), and P. malariae (Pm) are also endemic. Blood samples (n = 31,234) were collected from children aged 0-14 years during a 2018 nationwide HIV survey and assayed for Plasmodium antigenemia, Plasmodium DNA, and IgG against Plasmodium MSP1-19 antigens. Of all children, 6.6% were estimated to have Pm infection and 1.4% Po infection with no Pv infections detected. The highest household wealth quintile was strongly protective against infection with Pm (aOR: 0.11, 95% CI: 0.05-0.22) or Po (aOR= 0.01, 0.00-0.10). Overall Pm seroprevalence was 34.2% (95% CI: 33.3-35.2) with lower estimates for Po (12.1%, 11.6-12.5) and Pv (6.3%, 6.0-6.7). Pm seropositivity was detected throughout the country with several local government areas showing >50% seroprevalence. Serological and DNA indicators show widespread exposure of Nigerian children to Pm with lower rates to Po and Pv

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

Exposure, infection, systemic cytokine levels and antibody responses in young children concurrently exposed to schistosomiasis and malaria

Despite the overlapping distribution of Schistosoma haematobium and Plasmodium falciparum infections, few studies have investigated early immune responses to both parasites in young children resident in areas co-endemic for the parasites. This study measures infection levels of both parasites and relates them to exposure and immune responses in young children. Levels of IgM, IgE, IgG4 directed against schistosome cercariae, egg and adult worm and IgM, IgG directed against P. falciparum schizonts and the merozoite surface proteins 1 and 2 together with the cytokines IFN-γ, IL-4, IL-5, IL-10 and TNF-α were measured by ELISA in 95 Zimbabwean children aged 1–5 years. Schistosome infection prevalence was 14·7% and that of Plasmodium infection was 0% in the children. 43. 4% of the children showed immunological evidence of exposure to schistosome parasites and 13% showed immunological evidence of exposure to Plasmodium parasites. Schistosome–specific responses, indicative of exposure to parasite antigens, were positively associated with cercariae-specific IgE responses, while Plasmodium-specific responses, indicative of exposure to parasite antigens, were negatively associated with responses associated with protective immunity against Plasmodium. There was no significant association between schistosome-specific and Plasmodium-specific responses. Systemic cytokine levels rose with age as well as with schistosome infection and exposure. Overall the results show that (1) significantly more children are exposed to schistosome and Plasmodium infection than those currently infected and; (2) the development of protective acquired immunity commences in early childhood, although its effects on infection levels and pathology may take many years to become apparent

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

Cross-Reactivity of Two SARS-CoV-2 Serological Assays in a Setting Where Malaria Is Endemic

Background: Accurate SARS-CoV-2 serological assays are critical for COVID-19 serosurveillance. However, previous studies have indicated possible cross-reactivity of these assays, including in malaria-endemic areas.Methods: We tested 213 well-characterized pre-pandemic samples from Nigeria using two SARS-CoV-2 serological assays: Abbott Architect IgG and Euroimmun NCP IgG assay, both targeting SARS-CoV-2 nucleocapsid protein. To assess antibody binding strength, an avidity assay was performed on these samples and on plasma from SARS-CoV-2 PCR-positive persons.Results: Thirteen (6.1%) of 212 samples run on the Abbott assay and 38 (17.8%) of 213 run on the Euroimmun assay were positive. Anti-Plasmodium IgG levels were significantly higher among false-positives for both Abbott and Euroimmun; no association was found with active P. falciparum infection. An avidity assay using various concentratIons of urea wash in the Euroimmun assay reduced loosely-bound IgG: of 37 positive/borderline pre-pandemic samples, 46%, 86%, 89%, and 97% became negative using 2M, 4M, 5M, and 8M urea washes, respectively. The wash slightly reduced avidity of antibodies from SARS-CoV-2 patients within 28 days of PCR confirmation; thereafter avidity increased for all urea concentrations except 8M.Conclusions: This validation found moderate to substantial cross-reactivity on two SARS-CoV-2 serological assays using samples from a malaria-endemic setting. A simple urea wash appeared to alleviate issues of cross-reactivity

Experience and Challenges from Clinical Trials with Malaria Vaccines in Africa.

Malaria vaccines are considered amongst the most important modalities for potential elimination of malaria disease and transmission. Research and development in this field has been an area of intense effort by many groups over the last few decades. Despite this, there is currently no licensed malaria vaccine. Researchers, clinical trialists and vaccine developers have been working on many approached to make malaria vaccine available.African research institutions have developed and demonstrated a great capacity to undertake clinical trials in accordance to the International Conference on Harmonization-Good Clinical Practice (ICH-GCP) standards in the last decade; particularly in the field of malaria vaccines and anti-malarial drugs. This capacity is a result of networking among African scientists in collaboration with other partners; this has traversed both clinical trials and malaria control programmes as part of the Global Malaria Action Plan (GMAP). GMAP outlined and support global strategies toward the elimination and eradication of malaria in many areas, translating in reduction in public health burden, especially for African children. In the sub-Saharan region the capacity to undertake more clinical trials remains small in comparison to the actual need.However, sustainability of the already developed capacity is essential and crucial for the evaluation of different interventions and diagnostic tools/strategies for other diseases like TB, HIV, neglected tropical diseases and non-communicable diseases. There is urgent need for innovative mechanisms for the sustainability and expansion of the capacity in clinical trials in sub-Saharan Africa as the catalyst for health improvement and maintained