The ultrasensitive Alere Plasmodium falciparum Malaria Ag histidine-rich protein 2 rapid diagnostic test (Alere uRDT, Suwon City, South Korea) is a new diagnostic tool which is more expensive than other malaria rapid diagnostic tests (RDTs) routinely used in Ugandan clinics. The manufacturer recommends testing samples within 2 days and scoring results after 20 minutes, which may be impractical in high-volume resource-poor clinics. We compared testing by the Alere Ag rapid diagnostic test (uRDT), CareStart RDT, microscopy, and an ultrasensitive I8S rRNA quantitative reverse transcription polymerase chain reaction (qRT-PCR) using survey and clinical samples. For the Alere uRDT, we used survey blood samples stored at 4°C for 44 days and for some clinical samples deliberately scored results beyond 20 minutes. The Alere uRDT and qRT-PCR identified asymptomatic parasitemia cases in 56% and 72%, respectively, of survey samples originally scored as negative by the CareStart RDT. Using qRT-PCR as a gold standard, the Alere uRDT was superior to the CareStart RDT in estimating asymptomatic parasite prevalence in a cross-sectional survey (P = 0.007) and in detection of clinically significant malaria; both RDTs were comparable in detecting asymptomatic parasitemia in the clinic (P = 0.599). Scoring Alere uRDT results at 20 minutes produced valid results confirmed by the CareStart RDT, but there was a consistent background; scoring the Alere uRDT beyond 20 minutes produced false-positive results. The Alere uRDT outperformed the CareStart RDT (ACCESSBIO, Somerset, NJ) in a field survey in estimating malaria prevalence and in the clinic for symptomatic malarial illness. It produced reliable results using samples stored at 4°C for 44 days, but test results read beyond 20 minutes were invalid.
Objective Uganda has registered fewer COVID-19 cases and deaths per capita than Western countries. Lower numbers of cases and deaths might be due to pre-existing cross-immunity induced by circulating common cold human coronaviruses (HCoVs) before the COVID-19 pandemic. To investigate pre-existing mucosal antibodies against COVID-19, we compared IgA reactivity to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and HCoVs in milk of mothers collected in 2018. Methods Ugandan and US milk samples were run on enzyme-linked immunoadsorbent assay (ELISA) to measure specific IgA to SARS-CoV-2 and HCoVs NL63, OC43, HKU1, and 229E spike proteins. Pooled plasma from US COVID-19 positive and negative cases were positive and negative controls, respectively. Results One Ugandan mother had high milk IgA reactivity against all HCoVs and SARS-CoV-2 spike proteins. Ugandan mothers had significantly higher IgA reactivity against the betacoronavirus HCoV-OC43 than US mothers (p = 0.018). By contrast, US mo thers had significantly higher IgA reactivity against the alphacoronaviruses HCoV-229E and HCoV-NL63 than Ugandan mothers (p < 0.0001 and 0.035, respectively). Conclusion Some Ugandan mothers have pre-existing HCoV-induced IgA antibodies against SARS-CoV-2 which may be passed to infants via breastfeeding.
ObjectiveUganda, like other African countries, has registered fewer COVID-19 cases and deaths per capita than non-African countries. The lower numbers of cases and deaths in Uganda might be due to pre-existing cross-immunity induced by zoonotic coronaviruses or circulating common cold human coronaviruses (HCoVs) before the COVID-19 pandemic. In order to test this premise, we compared IgA reactivity to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and HCoVs in breast milk of US and rural Ugandan mothers collected in 2018 before the COVID-19 epidemic. Ugandan and US pre-pandemic breast milk samples were run in duplicate on enzyme-linked immunoadsorbent assay (ELISA) to measure specific IgA antibody reactivity to the spike proteins of SARS-CoV-2, human coronaviruses (HCoV) NL63, OC43, HKU1, and 229E. Pooled plasma from US COVID-19 positive and negative cases were employed as positive and negative controls, respectively. One Ugandan pre-pandemic milk sample had remarkably high reactivity against all HCoVs and SARS-CoV-2 spike proteins. There was higher IgA reactivity against the betacoronavirus HCoV-OC43 in Ugandan pre-pandemic milk samples by comparison with US pre-pandemic milk samples (p = 0.018). By contrast, there was significantly higher IgA reactivity against the alphacoronaviruses HCoV-229E and HCoV-NL63 in US pre-pandemic milk samples by comparison with Ugandan pre-pandemic milk samples (p < 0.0001 and 0.035, respectively).ConclusionSome Ugandan mothers may have robust pre-existing immunity against SARS-CoV-2 due to cross-immunity induced by HCoVs which may be passed on to their infants via breastfeeding. The differential pre-pandemic reactivity of US mothers to HCoV 229E and HCoV NL63 may have contributed to suboptimal antibody responses to SARS-CoV-2.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.