Use of conventional PCR for the detection of the African Swine Fever virus in apparently healthy traditional and semi-modern pig farms in Chad

Abstract

Objective: The objective of this work is to detect the ASF virus genome in the carcasses and viscera of apparently healthy pigs slaughtered at different slaughter sites in Chad. Material and method: The study was conducted over a period of 12 months from September 2021 to September 2022 in the provinces of Chari Baguirmi, Mayo Kébbi East and N’Djamena. It began with two censuses. A first census among 492 farmers who had already recorded ASF and then a second census on 26 slaughter areas in the study area. A total of 50 organs were collected and analyzed by the conventional PCR technique for the detection of viral DNA. The data from the interviews as well as the molecular biology results were analyzed with the R Studio software. Results: The results of this study revealed a prevalence viral which varies from 13.33% to 52.17% from one province to another. In cities and sub-prefectures, the prevalence was between 22.22% to 57.14% and 16.66% to 40% varied from one city to another. The prevalence in the arrondissements was between 38.46% to 70% as well as in the cantons and it was from 0% to 50%. The study also revealed that variations in the detection of ASF virus DNA are linked to types of breeding, age groups of pigs, gender of animals, breed, general and physiological condition of animals before slaughter. The prevalence of viral genome detection in organs ranged from 25.19% to 50.19% Conclusion: This work has shown that the ASF virus replicates quietly in some pig farms in Chad, despite the absence of apparent clinical signs. The presence of this virus in farms is maintained by the inadequacy of biosecurity measures and poor farming practices, but above all the lack of a slaughter area dedicated to this sector.