Background: The Hepatitis B virus (HBV) vaccine is used worldwide as an efficient tool to prevent the occurrence of chronic HBV infection and the subsequent liver disease. However, despite decades of vaccination campaigns, millions of new infections are still reported every year. Here, we aimed to assess the nationwide HBV vaccination coverage in Mauritania as well as the presence of protective levels of the antibodies against HBV surface antigen (HBsAb) following vaccination in a sample of children immunized as infants. Methods: To evaluate the frequency of fully vaccinated and seroprotected children in Mauritania, a prospective serological study was conducted in the capital. First, we evaluated the pediatric HBV vaccine coverage in Mauritania between 2015 and 2020. Then, we examined the level of antibodies against HBV surface antigen (HBsAb) in 185 fully vaccinated children (aged 9 months to 12 years) by ELISA using the VIDAS hepatitis panel for Minividas (Biomerieux). These vaccinated children were sampled in 2014 or 2021. Results: In Mauritania, between 2016 and 2019, more than 85% of children received the complete HBV vaccine regimen. While 93% of immunized children between 0 and 23 months displayed HBsAb titer >10 IU/L, the frequency of children with similar titers decreased to 63, 58 and 29% in children aged between 24–47, 48–59 and 60–144 months, respectively. Conclusions: A marked reduction in the frequency of HBsAb titer was observed with time, indicating that HBsAb titer usefulness as marker of protection is short lived and prompting the need for more accurate biomarkers predictive of long-term protection.

Background: Since quantitative indices are essential for quantifying the depth of ethnobotanical knowledge, most current measures aim to account for the complexity of practical knowledge combinations by focusing on species importance or consensus. One new way to measure cultural variation in plant-use knowledge is the Combination Use Variation Index (CUDI), which is introduced in this study. Methods: CUDI is calculated by taking the number of unique “species × use” combinations a group reports and dividing it by the total number of possible combinations. Five imagined datasets for different cultural groups were created to see how the index works under different conditions of species variety, use category variety, and knowledge organization. Comparative analyses with established indices (UV, ICF, BEI, RFC, RSI) were performed. Results: CUDI values proved highly sensitive to the structure and breadth of knowledge, increasing with greater functional diversity and polyvalence in plant-use combinations, while remaining robust to differences in sample size. Comparative analysis showed that CUDI adds to traditional indices by focusing on practical usefulness instead of just how often something is cited or how much agreement there is among informants. Conclusions: When it comes to ethnobotanical research, CUDI gives researchers a transparent, robust, and easily reproducible way to quantify practical knowledge variety. Researchers can modify it for use in different fields of ethnobiology, and it addresses a methodological need in research that spans cultures and communities. Possible future uses include tracking how our understanding evolves, ranking conservation efforts, and honing quantitative ethnobotany. Keywords: CUDI, Cross-cultural comparison, Ethnobiology, Ethnobotany, Intra-group comparison, Quantitative analysis, Traditional knowledge

Background: In the province of Adrar (northern Mauritania), there is significant interest in medicinal plants and their use. However, the utilization of herbal medicines has been largely underestimated, with little or no scientific data regarding the status, perception of inhabitants of northern Mauritania, confidence in the healing properties of medicinal plants, and the conservation of traditional medicinal heritage of the local population. Methods: The semi-structured interviews, and questionnaires were conducted between 2014 and 2016 in the 11 municipalities of Adrar province. A total of 120 participants aged from 20 to 90 years old, including 24 herbalists and 28 traditional healers. The ethnobotanical data were quantitatively analyzed using indices such as relative popularity level (RPL), rank order priority (ROP), the Medicinal Plant Knowledge index (MPKi), the Medicinal Plant Use index (MPUi), and the Informant consensus factor (ICF). Results: In the present study, we identified 68 taxa from 27 different botanical families. The most significant family is Fabaceae, with 14 species. These plants are used to treat 50 conditions or symptoms grouped into 14 pathological groupings according to the international classification of primary care (ICPC-2). The analysis revealed that the highest value of MPU was obtained for Vachellia tortilis (Forssk.) Galasso &Banfi., Adansonia digitate L. and Balanites aegyptiaca (L.) Delile (MPUi= 100%). In addition, the high fidelity level (FL=100) was recorded for Vachellia tortilis, Adansonia digitata and Balanites aegyptiaca, these three species a very high capability (ROP=100) in improving hypertension and Diabetes. For the Informant Consensus Factor (ICF) the most prevalent groups were Cardiovascular (K) with (ICF=0.97). Conclusions: The knowledge revealed in this study provides a particularly unique source of information on local traditional medicine and adds value to Adrar province. Keywords: Mauritanian plants, Medicinal plants, Adrar, ethnobotany, ethnomedicine, traditional medicine.

Mauritania has the most detailed and diverse knowledge on traditional plant remedies of medicinal plant use, despite its comparatively limited native flora