Plasmodium infection is associated with cross-reactive antibodies to carbohydrate epitopes on the SARS-CoV-2 Spike protein.

Sero-surveillance can monitor and project disease burden and risk. However, SARS-CoV-2 antibody test results can produce false positive results, limiting their efficacy as a sero-surveillance tool. False positive SARS-CoV-2 antibody results are associated with malaria exposure, and understanding this association is essential to interpret sero-surveillance results from malaria-endemic countries. Here, pre-pandemic samples from eight malaria endemic and non-endemic countries and four continents were tested by ELISA to measure SARS-CoV-2 Spike S1 subunit reactivity. Individuals with acute malaria infection generated substantial SARS-CoV-2 reactivity. Cross-reactivity was not associated with reactivity to other human coronaviruses or other SARS-CoV-2 proteins, as measured by peptide and protein arrays. ELISAs with deglycosylated and desialated Spike S1 subunits revealed that cross-reactive antibodies target sialic acid on N-linked glycans of the Spike protein. The functional activity of cross-reactive antibodies measured by neutralization assays showed that cross-reactive antibodies did not neutralize SARS-CoV-2 in vitro. Since routine use of glycosylated or sialated assays could result in false positive SARS-CoV-2 antibody results in malaria endemic regions, which could overestimate exposure and population-level immunity, we explored methods to increase specificity by reducing cross-reactivity. Overestimating population-level exposure to SARS-CoV-2 could lead to underestimates of risk of continued COVID-19 transmission in sub-Saharan Africa.

Sociocultural descriptions of febrile syndromes in rural areas of Urabá, Colombia: An exploration of "tick fever" / Descrição sociocultural de síndromes febris em áreas rurais de Antioquia Urabá: um olhar sobre a "febre do carrapato"

Abstract Introduction: In 2006 and 2008 there were two lethal outbreaks of rickettsioses in the rural areas of Urabá, characterized by the lack of immediate diagnosis and antibiotic treatment. Objective: Describe sociocultural aspects about knowledge, attitudes and practices in relation to febrile syndromes and "tick fever" in rural areas of Urabá. Materials and methods: We conducted an exploratory study using knowledge, attitudes, and practices questionnaires and semi-structured interviews about febrile syndromes and "tick fever". We surveyed 246 heads of households and interviewed nine individuals. Results: We observed that people tended to identify febrile syndromes with signs and clinical symptoms of dengue, malaria, leptospirosis and rickettsioses. A considerable proportion of individuals (32.93%) knew very little about "tick fever", thinking that is was transmitted by mosquitos. They mentioned intestinal parasitoids, malaria, dengue, and "evil eye" among the causes of febrile syndromes. "Tick fever" is linked by its name to the bite of the tick. Furthermore, the treatments for febrile syndromes mentioned by interviewees are associated to those commonly used in western medicine and medicinal plants. Conclusions: There is a need for educational programs in rural areas, to raise awareness about these potential lethal conditions that can be effectively treated.

Resumo Introdução: Nos anos de 2006 e 2008, dois surtos letais de riquetsiose foram relatados em áreas rurais de Urabá, caracterizados pela falta de atenção imediata para o diagnóstico e tratamento com antibióticos. Objetivo: Descrever aspectos socioculturais do conhecimento, atitudes e práticas de síndromes febris e "febre do carrapato" em áreas rurais de Antioquia, Urabá. Materiais e métodos: Realizou-se estudo exploratório, através de inquéritos sobre CAP (conhecimentos, atitudes e práticas) e entrevistas semiestruturadas sobre síndromes febris e "febre do carrapato", um nome que se refere às doenças das riquetsioses na área. Foram aplicados 246 inquéritos sobre a CAP foram realizadas aos chefes de agregados familiares e nove pessoas foram entrevistadas. Resultados: Observou-se que as pessoas tendem a identificar os sinais e sintomas clínicos característicos da dengue, malária, leptospirose e até riquetsiose. Um grande número de pessoas demonstra baixo conhecimento sobre "febre do carrapato" e indicou que ela é transmitida por mosquitos (32,93%). Os entrevistados indicaram que as causas das diferentes síndromes febris se devem a parasitas intestinais, malária, dengue ou, como crença cultural, ao "mau olhado". A "febre do carrapato" o associa, pelo nome, com a mordida do carrapato. Além disso, o tratamento das síndromes febris referidas pelos entrevistados está intimamente relacionado ao uso comum da medicina ocidental e ao uso de "plantas medicinais". Conclusões. É necessário ter programas de educação nessas áreas rurais para que essas entidades potencialmente letais tenham um tratamento efetivo e acessível.