A combined effort of 11 laboratories in the WHO African region to improve quality of Buruli ulcer PCR diagnosis: The "BU-LABNET".

Buruli ulcer is one of the 20 neglected tropical diseases in the world. This necrotizing hypodermitis is a chronic debilitating disease caused by an environmental Mycobacterium ulcerans. At least 33 countries with tropical, subtropical and temperate climates have reported Buruli ulcer in African countries, South America and Western Pacific regions. Majority of cases are spread across West and Central Africa. The mode of transmission is unclear, hindering the implementation of adequate prevention for the population. Currently, early diagnosis and treatment are crucial to minimizing morbidity, costs and preventing long-term disability. Biological confirmation of clinical diagnosis of Buruli ulcer is essential before starting chemotherapy. Indeed, differential diagnosis are numerous and Buruli ulcer has varying clinical presentations. Up to now, the gold standard biological confirmation is the quantitative PCR, targeting the insertion sequence IS2404 of M. ulcerans performed on cutaneous samples. Due to the low PCR confirmation rate in endemic African countries (under 30% in 2018) for numerous identified reasons within this article, 11 laboratories decided to combine their efforts to create the network "BU-LABNET" in 2019. The first step of the network was to harmonize the procedures and ship specific reagents to each laboratory. With this system in place, implementation of these procedures for testing and follow-up was easy and the laboratories were able to carry out their first quality control with a very high success rate. It is now time to integrate other neglected tropical diseases to this platform, such as yaws or leprosy.

Prevalence of SARS-CoV-2 among high-risk populations in Lomé (Togo) in 2020

ObjectiveThis survey aims at estimating the prevalence of SARS-CoV-2 in high risk populations in Lome. MethodsFrom April 23rd to May 8th 2020, we recruited a random sample of participants from five sectors: healthcare, air transport, police, road transport and informal. We collected oropharyngeal swab for direct detection through real time reverse transcription polymerase chain reaction (rRT-PCR), and blood for antibodies detection by serological tests. The overall prevalence (current and past) of infection was defined by positivity for both tests. ResultsA total of 955 participants with a median age of 36 (IQR 32-43) were included and 71.6% (n=684) were men. Around 22.1% (n=212) were from the air transport sector, 20.5% (n=196) in the police, and 38.7% (n=370) in the health sector. Seven participants (0.7%, 95% CI: 0.3-1.6%) had a positive rRT-PCR at the time of recruitment and nine (0.9%, 95% CI: 0.4-1.8%) were seropositive for IgM or IgG against SARS-CoV-2. We found an overall prevalence of 1.6% (n=15), 95% CI: 0.9-2.6%. ConclusionThe prevalence of the SARS-CoV-2 infection among high-risk populations in Lome was relatively low and could be explained by the various measures taken by the Togolese government. Therefore, we recommend targeted screening.