Plasmodium falciparum EBA175 and PfRh2 belong to two main families involved in parasite invasion, and both are potential vaccine candidates. Current knowledge is limited regarding which target antigens and subclasses of antibodies are actually important for protection, and how naturally acquired immunity is achieved. Repeated blood samples were collected from individuals in Nigeria over a period of almost one year. ELISA was used to analyse subclasses of IgG responses. For both EBA175 (region III-V) and (a fragment of) PfRh2, the dominant antibody responses consisted of IgG1 and IgG3 followed by IgG2, while for PfRh2 there was also a relatively prominent response for IgG4. High levels of IgG1, IgG2 and IgG3 for EBA175 and total IgG for PfRh2 correlated significantly with a lower parasitaemia during the study period. Children with HbAS had higher levels of some subclasses compared to children with HbAA, while in adults the pattern was the opposite. The half-lives of IgG2 and IgG4 against EBA175 were clearly shorter than those for IgG1 and IgG3. EBA175 and PfRh2 are potential targets for protective antibodies since both correlated with lower parasitaemia. The shorter half-lives for IgG2 and IgG4 might explain why these subclasses are often considered less important in protection against malaria. Triggering the right subclass responses could be of critical importance in a successful vaccine. Further studies are needed to evaluate the role of haemoglobin polymorphisms and their malaria protective effects in this process.

Giardia duodenalis is a significant contributor to the burden of diarrheal disease in sub-Saharan Africa. This study assesses the occurrence and molecular diversity of G. duodenalis and other intestinal parasites in apparently healthy children (n = 311) in Ibadan, Nigeria. Microscopy was used as a screening method and PCR and Sanger sequencing as confirmatory and genotyping methods, respectively. Haplotype analyses were performed to examine associations between genetic variants and epidemiological variables. At microscopy examination, G. duodenalis was the most prevalent parasite found (29.3%, 91/311; 95% CI: 24.3–34.7), followed by Entamoeba spp. (18.7%, 58/311; 14.5–23.4), Ascaris lumbricoides (1.3%, 4/311; 0.4–3.3), and Taenia sp. (0.3%, 1/311; 0.01–1.8). qPCR confirmed the presence of G. duodenalis in 76.9% (70/91) of the microscopy-positive samples. Of them, 65.9% (60/91) were successfully genotyped. Assemblage B (68.3%, 41/60) was more prevalent than assemblage A (28.3%, 17/60). Mixed A + B infections were identified in two samples (3.3%, 2/60). These facts, together with the absence of animal-adapted assemblages, suggest that human transmission of giardiasis was primarily anthroponotic. Efforts to control G. duodenalis (and other fecal-orally transmitted pathogens) should focus on providing safe drinking water and improving sanitation and personal hygiene practices.

Anemia is a common malaria-associated complication in pregnant women in endemic regions. Phosphatidylserine (PS) is exposed to the immune system during the massive destruction of red blood cells (RBCs) that accompany malaria, and antibodies against PS have been linked to anemia through destruction of uninfected RBCs. We determined levels of anti-PS IgG antibodies in pregnant women in Ibadan, Nigeria and correlated them to parameters of importance in development of anemia and immunity. Anti-PS correlated inversely with Packed Cell Volume (PCV), indicating that the antibodies could contribute to anemia. There was no correlation with anti-VAR2CSA IgG, haptoglobin or parasitemia, indicating that the modulation of anti-PS response is multifactorial in nature. Anti-PS levels were lowest in multigravidae compared to both primigravidae and secundigravidae and correlated inversely with age. In conclusion, lower levels of anti-PS in multigravidae could be beneficial in avoiding anemia.

Background: In developing countries, infections caused by soil-transmitted helminthes (STH), such asAscaris, Trichurisand hookworm, pose major public health problems among the school-age children, resulting in impaired physical growth such as stunting and thinness, and cognitive development. The aim of this study is to determine the prevalence of STH infections, stunting and thinness, and risk factors among school-age-children in Ibadan. This becomes highly imperative in order to serve as a guide on the prevention and control.Method: A cross-sectional study was carried out in 8 primary schools at Ibadan, Oyo State Nigeria, between May and November 2018. All the school-age-children between the ages 5 and 18 years old (mean 10.4 ± 1.7 years), from primary one to six took part in the study. Demographic data were obtained and STH infections was analysed in single-stool samples by Kato-Katz. Anthropometric parameters were taken to calculate Height for-age Z score (HAZ) and Body-Mass-Index (BMI) for-age Z score (BAZ), in order to determine among school-aged-children stunting and thinness respectively.Results: In overall, 458 school-age-children partook in the study. The prevalence of STH was 9.0%, out of which 7.6%, 2.8% and 1.5% were recorded forAscaris, Trichurisand multiparasitism respectively. The overall prevalence obtained revealed that the results of stunting and thinness (HAZ < -2SD, BAZ < -2SD) were 24.7% and 27.3% respectively based on the WHO Child Growth Standards (2007). Notably, ages of the children (P< 0.01), their classes (P=0.05), different schools (P=0.003), washing of hands after toileting (P= 0.05) were important risk factors determining STH infection, HAZ and BAZ.Conclusion: The study showed that specific risk factors among school children in the studied area will make them vulnerable with high risk of STH infection, HAZ and BAZ. Effective prevention and control strategies can be well planned when risk factors and dynamics of transmission in vulnerable groups have been painstakingly identified.Summary: Ascaris, Trichurisand hookworm are responsible for major public health problems among the school-age children (SAC); this has led to stunting and thinness, and impaired cognitive development. With the aim to determine prevalence of STH infections, stunting, thinness and associated risk factors, a cross-sectional study of STH infection in 8 primary schools at Ibadan, Oyo State Nigeria was conducted in 2018. School-aged children between the ages of 5 and 18 were enrolled, demographic data, stool samples and anthropometric parameters were obtained in order to determine STH infection and nutritional status. 9.0% was the prevalence of STH, the prevalence of 7.6%, 2.8% and 1.5% were recorded forAscaris, Trichurisand multiparasitism respectively, while 24.7% and 27.3% were obtained for stunting and thinness respectively. The children’s age, hand washing after toileting and locations of the different schools were significantly correlated with STH infection, HAZ and BAZ. This study is highly imperative because its shows some risk factors associated with STH infection, HAZ and BAZ among SAC, this can serve as a guide on the prevention and control among SAC.