AUTHOR=Wu Hao , Tian Zihan , Yao Lun , Ghonaim Ahmed H. , Chen Xiaoyu , Ruan Shengnan , Li Huimin , Li Wentao , He Qigai 

TITLE=Combination of Fe(OH)3 modified diatomaceous earth and qPCR for the enrichment and detection of African swine fever virus in water

JOURNAL=Frontiers in Veterinary Science

VOLUME=Volume 9 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/veterinary-science/articles/10.3389/fvets.2022.1045190

DOI=10.3389/fvets.2022.1045190

ISSN=2297-1769

ABSTRACT=Water is one of the primary vectors for African swine fever virus (ASFV) transmission among swine herds. However, the low concentrations of ASFV in water represent a challenge for the detection of the virus by conventional PCR methods, and enrichment of the virus would increase the test sensitivity. In this study, a rapid and efficient water-borne virus enrichment system (MDEF, modified diatomaceous earth by ferric hydroxide colloid) was used to enrich ASFV in water. After enrichment by MDEF, conventional real-time PCR (qPCR) was used for ASFV detection. ASFV were inactivated and diluted in 10 L of water, of which 4 mL were collected after 60 minutes using the MDEF system. Two thousand times reduction of the sample volume was achieved after enrichment. A high adsorption rate of about 99.99 (± 0.01)% and a high recovery rate of 64.01 (± 10.20)% to 179.65 (± 25.53)% was achieved by using 1g modified diatomaceous earth for 10 L ASFV contaminated water. The limit of qPCR detection of ASFV decreased to 1×10-1.11 GU ml-1 (genomic units per milliliter) from 1×102.71 GU ml-1 after concentrating the spiked water from 10 L to 4 ml. Preliminary application of MDEF allowed successful detection of african swine fever virus (ASFV), porcine circovirus type 2 (PCV2), and pseudorabies virus (PRV) in sewage. Thus, the combination of modified diatomaceous earth and real-time PCR is a promising strategy for the detection of viruses in water.