Arbovirus circulation, epidemiology and spatiotemporal distribution in Uganda

BackgroundArboviruses are endemic in Uganda; however, little is known about their epidemiology, seasonality, and spatiotemporal distribution. This study sought to provide information on arbovirus outbreaks from acute clinical presentations.MethodsA retrospective analysis of IgM and confirmatory Plaque Reduction Neutralization Test (PRNT)and results for arbovirus diagnosis of samples collected from 2016 to 2019 was carried out. Demographic data were used to determine the epidemiology and spatiotemporal distribution of arboviruses using the SaTScan and SPSS software.ResultsArbovirus activity peaked consistently during March-May rainy seasons. The overall arbovirus seroprevalence was 9·5% (137/1441). Of the 137 IgM positives, 72 (52·6%) were confirmed by PRNT, of which the central region (53/72; 73·6%) and YFV (20/72; 27·8%) had the highest prevalence. The 5-14 age group were four times more likely to be infected with an arbovirus p=0·003, 4·1 (1·3- 12·3 CI). Significant arboviral activity was observed among indoor (p=0·003) and outdoor (p=0·05) patients. Spatiotemporal analysis indicated arboviral activity in 23 districts with five distinct clusters in 6 districts. Masaka, in the Central region, was the most affected among the districts, with a significant YFV cluster (p˂0·001) from March to May 2016.InterpretationThis study shows that arbovirus activity peak during the March-May rainy season and highlights the need for YFV mass vaccination to reduce the clinical burden of arboviruses transmitted within the region

The Development and Validation of a Novel Nanobody-Based Competitive ELISA for the Detection of Foot and Mouth Disease 3ABC Antibodies in Cattle

Effective management of foot and mouth disease (FMD) requires diagnostic tests to distinguish between infected and vaccinated animals (DIVA). To address this need, several enzyme-linked immunosorbent assay (ELISA) platforms have been developed, however, these tests vary in their sensitivity and specificity and are very expensive for developing countries. Camelid-derived single-domain antibodies fragments so-called Nanobodies, have demonstrated great efficacy for the development of serological diagnostics. This study describes the development of a novel Nanobody-based FMD 3ABC competitive ELISA, for the serological detection of antibodies against FMD Non-Structural Proteins (NSP) in Uganda cattle herds. This in-house ELISA was validated using more than 600 sera from different Uganda districts, and virus serotype specificities. The evaluation of the performance of the assay demonstrated high diagnostic sensitivity and specificity of 94 % (95 % CI: 88.9–97.2), and 97.67 % (95 % CI: 94.15–99.36) respectively, as well as the capability to detect NSP-specific antibodies against multiple FMD serotype infections. In comparison with the commercial PrioCHECK FMDV NSP-FMD test, there was a strong concordance and high correlation and agreement in the performance of the two tests. This new developed Nanobody based FMD 3ABC competitive ELISA could clearly benefit routine disease diagnosis, the establishment of disease-free zones, and the improvement of FMD management and control in endemically complex environments, such as those found in Africa

The Development and Validation of a Novel Nanobody-Based Competitive ELISA for the Detection of Foot and Mouth Disease 3ABC Antibodies in Cattle

Effective management of foot and mouth disease (FMD) requires diagnostic tests to distinguish between infected and vaccinated animals (DIVA). To address this need, several enzyme-linked immunosorbent assay (ELISA) platforms have been developed, however, these tests vary in their sensitivity and specificity and are very expensive for developing countries. Camelid-derived single-domain antibodies fragments so-called Nanobodies, have demonstrated great efficacy for the development of serological diagnostics. This study describes the development of a novel Nanobody-based FMD 3ABC competitive ELISA, for the serological detection of antibodies against FMD Non-Structural Proteins (NSP) in Uganda cattle herds. This in-house ELISA was validated using more than 600 sera from different Uganda districts, and virus serotype specificities. The evaluation of the performance of the assay demonstrated high diagnostic sensitivity and specificity of 94 % (95 % CI: 88.9-97.2), and 97.67 % (95 % CI: 94.15-99.36) respectively, as well as the capability to detect NSP-specific antibodies against multiple FMD serotype infections. In comparison with the commercial PrioCHECK FMDV NSP-FMD test, there was a strong concordance and high correlation and agreement in the performance of the two tests. This new developed Nanobody based FMD 3ABC competitive ELISA could clearly benefit routine disease diagnosis, the establishment of disease-free zones, and the improvement of FMD management and control in endemically complex environments, such as those found in Africa