Comparison of loop-mediated isothermal amplification (LAMP) and cross-priming amplification (CPA) for detection of African swine fever virus.

The reliable and rapid diagnosis of infectious animal diseases presents an exceptionally im- portant aspect when considering their control and prevention. The paper describes the compara- tive evaluation of two rapid isothermal amplification methods for diagnosis of African swine fever (ASF). The robustness of loop-mediated isothermal amplification (LAMP) and the cross-priming amplification (CPA) were compared using samples obtained from ASF confirmed animals. Both assays were evaluated in order to define their diagnostic capabilities in terms of ASF diagnosis and reproducibility of the results. Investigations showed no cross-reactivity for other pig patho- gens and no significant differences in the specificity of both assays. The sensitivity of LAMP reached 90%, while that of CPA was 70%. In conclusion, both methods are suitable for imple- mentation in preliminary ASF diagnosis but further improvements are required to enhance their diagnostic sensitivity.

Development of cross-priming amplification for direct detection of the African Swine Fever Virus, in pig and wild boar blood and sera samples.

UNLABELLED: African swine fever (ASF) is considered a major threat to the production of pigs worldwide. The ASF aetiological agent, ASFV, is the sole member of the Asfivirus genus, belonging to the Asfarviridae family. An effective ASF vaccine is not currently available, thus the only measures of ASF spread control include, reliable and fast diagnosis. Officially approved, diagnostic methods include, virus isolation, serological assays, including enzyme-linked immunosorbent assay and immunoperoxidase assay (IPT) and different modifications of the polymerase chain reaction (PCR). This paper describes the first development and application of a cross-priming amplification method (CPA) for the direct detection of genetic ASFV material, in blood and sera from pigs and wild boars. This method is specific only to ASFV DNA. The study showed that CPA had equal sensitivity, in comparison to the official, universal probe library (UPL) real-time PCR and reached 7·2 copies of standard plasmid DNA, containing a p72 gene fragment. This method was capable of detecting ASFV DNA in all examined blood samples, originating from pigs; n = 10 and wild boars; n = 76. The obtained results were also confirmed by the officially approved, real-time PCR. The developed CPA might be further used by local and county veterinary officers, hunters or pig farmers, for preliminary ASF diagnosis. SIGNIFICANCE AND IMPACT OF THE STUDY: The spread of the African swine fever virus (ASFV) among infected pigs and wild boars, is currently one of the most important facets of virus transmission in eastern Europe. Cross-priming amplification (CPA) has been developed, for fast and direct development of genetic ASFV material in the blood and sera of infected pigs and wild boars. It has been shown that CPA is a rapid, sensitive and specific isothermal method for the detection of ASFV DNA, in directly collected blood or sera from pigs and wild boars.