PA-811 High malaria and arbovirus IgM/AgNS1 seropositivity in children with acute febrile illness in Libreville, the capital city of Gabon

BackgroundAcute febrile illness (AFI) management represents a challenge in sub-Saharan Africa where appropriate tools for the screening are often lacking. The aim of this study was to determine the prevalence of single and co-infection of malaria and arbovirus in children with AFI in a malaria sentinel site, Gabon.MethodsFrom July to December 2022, patients with AFI and presenting at the malaria sentinel were screened for malaria and dengue (DENV), Chikungunya (CHIKV) and Zika (ZIKV). Malaria was diagnosed using microscopy, while arbovirus infections were investigated with RDT detecting specific IgM (CHIKV and DENV); NS1 antigen and IgM for ZIKA by. Haematological parameters were analysed. ResultsA total of 524 acute febrile cases were included, their median age was 60 [24.0–132.0] months. The prevalence of malaria was 38.9% (n=199/524), P.falciparum was the only plasmodial species detected. Arbovirus RDT positivity rate was 39.1% (n=205/524). Overall, 184 (35.1%) participants were tested positive for ZIKV, 86 for NS1 antigen; 72 for ZIKV specific IgM and 26 for both NS1 antigen and IgM. DENV specific IgM was detected in 42 (8.0%) patients while CHIKV IgM rate was 0.6% (n=3). Considering the number of detected infections, 187 (35.7%) patients were infected by one pathogen, 92 (17.6%) by two and 19 (3.6%) by three pathogens. Co-infections were frequent, Malaria-Zika virus infection predominated (17.3%, n=92). The median Hb level was different according to the type of infection, it was the lowest in case of co-infection (p=0.03). The median platelet count was significantly lower in case of coinfection, patients were at 8-fold higher risk of having thrombocytopenia (OR: 8.7; IC95% [5.3- 14.2], p