Effects of anti-malarial prophylaxes on maternal transfer of Immunoglobulin-G (IgG) and association to immunity against Plasmodium falciparum infections among children in a Ugandan birth cohort.

BACKGROUND: The in-utero transfer of malaria specific IgG to the fetus in Plasmodium falciparum infected pregnant women potentially plays a role in provision of immune protection against malaria in the first birth year. However, the effect of Intermittent Prophylactic Treatment in Pregnancy (IPTp) and placental malaria on the extent of in-utero antibody transfer in malaria endemic regions like Uganda remain unknown. The aim of this study was thus to establish the effect of IPTp on in-utero transfer of malaria specific IgG to the fetus and the associated immune protection against malaria in the first birth year of children born to mothers who had P. falciparum infection during pregnancy in Uganda. METHODS: We screened a total of 637 cord blood samples from a double blinded randomized clinical trial on Sulfadoxine-Pyrimethamine (SP) and Dihydroartemisinin-Piperaquine (DP) IPTp in a Ugandan birth cohort; study conducted from Busia, Eastern Uganda. Luminex assay was used to measure the cord levels of IgG sub-types (IgG1, IgG2, IgG3 and IgG4) against 15 different P. falciparum specific antigens, with tetanus toxoid (t.t) as a control antigen. Man-Whitney U test (non-parametric) in STATA (ver15) was used in statistical analysis of the samples. In addition, Multivariate cox regression analysis was used to determine the effect of maternal transfer of IgG on the incidence of malaria in the first birth year of children under study. RESULTS: Mothers on SP expressed higher levels of cord IgG4 against erythrocyte binding antigens (EBA140, EBA175 and EBA181) (p<0.05). Placental malaria did not affect cord levels of IgG sub-types against selected P. falciparum specific antigens (p>0.05). Children who expressed higher levels (75th percentile) of total IgG against the six key P. falciparum antigens (Pf SEA, Rh4.2, AMA1, GLURP, Etramp5Ag1 and EBA 175) had higher risk of malaria in the first birth year; AHRs: 1.092, 95% CI: 1.02-1.17 (Rh4.2); 1.32, 95% CI: 1.00-1.74 (PfSEA); 1.21, 95%CI: 0.97-1.52 (Etramp5Ag1); 1.25, 95%CI: 0.98-1.60 (AMA1); 1.83, 95%CI: 1.15-2.93 (GLURP) (GLURP), and 1.35,; 95%CI: 1.03-1.78 (EBA175). Children born to mothers categorized as poorest had the highest risk of malaria infections in the first birth year (AHR: 1.79, 95% CI: 1.31-2.4). Children born to mothers who had malaria infections during gestation had higher risk of getting malaria in the first birth year (AHR 1.30; 95%CI: 0.97-1.7). CONCLUSION: Malaria prophylaxis in pregnant mothers using either DP or SP does not affect expression of antibodies against P. falciparum specific antigens in the cord blood. Poverty and malaria infections during pregnancy are key risk factors of malaria infections in the first birth year of growth of children. Antibodies against P. falciparum specific antigens does not protect against parasitemia and malaria infections in the first birth year of children born in malaria endemic areas.

Prevalence and antimicrobial resistance profiles of Neisseria gonorrhea and Chlamydia trachomatis isolated from individuals attending STD clinics in Kampala, Uganda.

Background: Sexually transmitted diseases (STDs) management in sub-Saharan Africa is syndromic but molecular diagnostics provide quicker, sensitive diagnosis and treatment. Effective STD control hinges on identification and treatment of infected persons and sexual partner contact tracing. Objectives: This study assessed feasibility of using the Xpert CT/NG test to identify prevalent Chlamydia trachomatis (CT) and Neisseria gonorrhea (NG) infections among STD clinic attendees and their sexual partners and tested for antimicrobial resistance for N. gonorrhea. Methods: A cross-sectional study was conducted at 4 outpatient STD clinics in Kampala, Uganda from February 2019 to October 2019. Participants received a syndromic diagnosis, were tested for NG and CT, as well as their sexual partners. Urine (men) and high vaginal swabs (women) were collected, examined using Xpert CT/NG assay. A total of 79 participants were enrolled at baseline of whom 25 had CT/NG. 21 partners of infected baseline participants and 7 partners of the 21 primary partners were enrolled. Results: The mean age of the reported sexual partners was 26 (18-43) years. The prevalence of NG was 25% at baseline and 18 % for CT. Nine (11.4%) people were dually infected. Men were more likely to have NG (p<0.001) at multivariable level. Two participants tested HIV-1 positive. On microbiological culture, 8 samples (2.5%) grew NG and all were resistant to penicillin, ciprofloxacin. For CT, we found a preponderance of the F-serovar in this population. Conclusion: The most prevalent organism was Neisseria gonorrhea. Generally, the prevalence of CT and NG was high. Infection proportions increased among primary partners, particularly women. Etiologic testing without partner tracing and treatment may underestimate burden of CT/NG in this population and contribute to re-infection.

Prevalence and antimicrobial resistance profiles of Neisseria gonorrhea and Chlamydia trachomatis isolated from individuals attending STD clinics in Kampala, Uganda

Background: Sexually transmitted diseases (STDs) management in sub-Saharan Africa is syndromic but molecular diagnostics provide quicker, sensitive diagnosis and treatment. Effective STD control hinges on identification and treatment of infected persons and sexual partner contact tracing. Objectives: This study assessed feasibility of using the Xpert CT/NG test to identify prevalent Chlamydia trachomatis (CT) and Neisseria gonorrhea (NG) infections among STD clinic attendees and their sexual partners and tested for antimicrobial resistance for N. gonorrhea. Methods: A cross-sectional study was conducted at 4 outpatient STD clinics in Kampala, Uganda from February 2019 to October 2019. Participants received a syndromic diagnosis, were tested for NG and CT, as well as their sexual partners. Urine (men) and high vaginal swabs (women) were collected, examined using Xpert CT/NG assay. A total of 79 participants were enrolled at baseline of whom 25 had CT/NG. 21 partners of infected baseline participants and 7 partners of the 21 primary partners were enrolled. Results: The mean age of the reported sexual partners was 26 (18-43) years. The prevalence of NG was 25% at baseline and 18 % for CT. Nine (11.4%) people were dually infected. Men were more likely to have NG (p<0.001) at multivariable level. Two participants tested HIV-1 positive. On microbiological culture, 8 samples (2.5%) grew NG, and all were resistant to penicillin, ciprofloxacin. For CT, we found a preponderance of the F-serovar in this population. Conclusion: The most prevalent organism was Neisseria gonorrhea. Generally, the prevalence of CT and NG was high. Infection proportions increased among primary partners, particularly women. Etiologic testing without partner tracing and treatment may underestimate burden of CT/NG in this population and contribute to re-infection