Detection of vaccine-like lumpy skin disease virus in cattle and Musca domestica L. flies in an outbreak of lumpy skin disease in Russia in 2017

Abstract

Since 2012, lumpy skin disease virus (LSDV) has been spreading from the Middle East to south-east Europe and Russia. Although vaccination campaigns have managed to contain LSDV outbreaks, the risk of further spread is still high. The most likely route of LSDV transmission in short distance spread is vector-borne. Several arthropod species have been suggested as potential vectors, but no proven vector has yet been identified. To check whether promiscuous-landing synanthropic flies such as the common housefly (Musca domestica) could be involved, we carried out entomological trapping at the site of a recent LSDV outbreak caused by a vaccine-like LSDV strain. The presence of vaccine-like LSDV DNA was confirmed by the assay developed herein, the assay by Agianniotaki et al. (2017) and RPO30 gene sequencing. No evidence of field LSDV strain circulation was revealed. In this study, we discovered that M. domestica flies carried vaccine-like LSDV DNA (C > 25.5), whereas trapped stable flies from the same collection were negative for both field and vaccine LSDV. To check whether flies were contaminated internally and externally, 50 randomly selected flies from the same collection were washed four times and tested. Viral DNA was mainly detected in the 1st wash fluid, suggesting genome or even viral contamination on the insect cadaver. In this study, internal contamination in the insect bodies without differentiation between the body locations was also revealed; however, the clinical relevance for mechanical transmission is unknown. Further work is needed to clarify a role of M. domestica in the transmission of LSDV. To our knowledge, this is the first report demonstrating that an attenuated LSD vaccine strain has been identified in Russian cattle given the ban on the use of live attenuated vaccines against LSDV.

Evidence of recombination of vaccine strains of lumpy skin disease virus with field strains, causing disease

“…As described in this study, since the GPCR locus of all isolates from 2018 carried the unique CTCAGTACAATT indel, they all tested positive for the vaccine strain in the assay developed by Agianniotaki et al [42]. They were negative for a LSDV vaccine signature in LSDV008 using a PCR, which only detects commercial LSDV vaccine isolates [27].…”

Determination of lumpy skin disease virus in bovine meat and offal products following experimental infection

“…Both types of clinical presentation were positive by PCR and VI in lymph nodes, and the affected internal organs were for DNA and infectious virus in clinically ill animals ( insects merit further investigation for their potential role in mechanical transmission. Muscidae flies have been implicated in carrying a vaccine-like LSDV that causes outbreaks of the generalized form (Sprygin, Pestova, Prutnikov, & Kononov, 2018). Moreover, the nonblood-sucking fly, Musca autumnalis, possesses prestomal teeth to rasp away the conjuctiva to stimulate the flow of tears (Giangaspero & Broce, 1993).…”

Entomological and Virological Methods for the Identification of Potential Vectors of Lumpy Skin Disease Virus in the South-Eastern Part of Northern Caucasus, Russia

“…Role of Stomoxys calcitrans as a vector of lumpy skin disease was investigated in several studies, which showed high potential of S.calcitrans for virus transmission [11][12][13]. The role of Musca domestica as a vector of LSDV is not yet clear, but case of detection of virus in M.domestica samples indicates its potential for mechanical transmission [14]. PCR protocol was effective for detection of LSDV genome in infected tissue cultures.…”