RESUMO
For the detection of African swine fever virus (ASFV) by polymerase chain reaction (PCR) in clinical samples, an internal control was constructed to identify false negative results in each reaction. The internal control was designed in such a way that the same primer pair was used to amplify the internal control and the target DNA which were differentiated by size. The lower detection limit was reached at about 30 internal control DNA copies and about 50 genomic ASFV DNA copies. The use of the internal control revealed that from a total of 12 uninfected samples, 10 samples contained inhibitors. After a one in two dilution, all ten of these samples amplified the internal control satisfactorily. From a total of 16 samples from pigs suspected of having ASF infection, nine contained inhibitors. After a one in two dilution, we observed internal control amplification and target DNA amplification for four samples.