Non-vector-borne transmission of lumpy skin disease virus

Abstract

The transmission of "lumpy skin disease virus" (LSDV) has prompted intensive research efforts due to the rapid spread and high impact of the disease in recent years, especially in eastern europe and Balkan countries. in this study, we experimentally evaluate the vaccine-derived virulent recombinant LSDV strain (Saratov/2017) and provide solid evidence on the capacity of the virus for transmission in a vectorproof environment. In the 60-day long experiment, we used inoculated bulls (IN group) and two groups of in-contact animals (C1 and C2), with the former (C1) being in contact with the inoculated animals at the onset of the trial and the latter (C2) being introduced at day 33 of the experiment. The infection in both groups of contact animals was confirmed clinically, serologically and virologically, and viremia was demonstrated in blood, nasal and ocular excretions, using molecular tools. further studies into LSDV biology are a priority to gain insights into whether the hypothesized indirect contact mode evidenced in this study is a de novo-created feature, absent from both parental stains of the novel (recombinant) LSDV isolate used, or whether it was dormant, but then unlocked by the process of genetic recombination. Author summary: in global terms, LSD has been termed a "neglected disease" due to its historic natural occurrence of being restricted to Africa and, occasionally, israel. However, after its slow spread throughout the Middle east, the disease is now experiencing a resurgence of research interest following a recent and rapid spread into more northern latitudes. Given the dearth of solid findings on potential transmission mechanisms, no efficient or reliable control program currently exists, which does not involve the use of live attenuated vaccines or stamping out policies-both of which are controversial for implementation in non-endemic regions or countries. the vector-borne mode is the only working concept currently available, but with scarce evidence to support the aggressive spread northwards-except for human-assisted spread, including legal or illegal animal transportation. the emergence of outbreaks is not consistently linked to weather conditions, with the potential for new outbreaks to occur and spread rapidly. Here, for the first time, we provide evidence for indirect contact-mode transmission for a naturally-occurring recombinant LSDV isolated from the field. In an insect-proof facility, we obtained solid evidence that the novel LSDV strain can pass to in-contact animals. Given the recombinant nature of the virus utilised, its genetic background relating to the observed transmission pattern within the study needs to be delineated.

The Importance of Quality Control of LSDV Live Attenuated Vaccines for Its Safe Application in the Field

“…Recombinants may influence LSDV transmission also at another level. Indirect non-vectored transmission has always been considered to be of minor importance [75] but recent experiments with a recombinant LSDV strain demonstrated the possibility of contact transmission [76]. Whether this contact transmission was solely due to the recombinant nature of the used LSDV challenge strain needs further investigation.…”

Genomic Characterisation of a Novel Avipoxvirus Isolated from an Endangered Northern Royal Albatross (Diomedea sanfordi)

“…Moreover, poxvirus infection can also occur through ingestion, parenteral inoculation, or droplet or aerosol exposure to mucous membranes or broken skin. Some poxviruses can be transmitted by fomites (inanimate objects) [ 43 ]. For example, studies have revealed that sheeppox and goatpox viruses are predominantly transmitted via aerosols [ 44 ]; whereas poxviruses from the genus Parapoxvirus can pass from one animal to another through direct or indirect contact.…”

Review: Vaccines and Vaccination against Lumpy Skin Disease

“…In 2017, the first recombinant LSDV Russia/Saratov/2017 was isolated from a bovine of a backyard farm in Saratov, close to the border with Kazakhstan, by Russian scientists. Later, the same research group provided experimental data on the virulence of this isolate [ 19 ] and also identified the second recombinant virus, LSDV Russia/Udmurtiya/2019, genetically close but still different from the first one. The study on the Russian recombinant LSDVs pointed out the potential role of illegal use of LSDV vaccines.…”

“…Direct contact [ 19 ] and seminal [ 20 ] transmission have been demonstrated experimentally, along with intrauterine transmission in the field [ 21 ]. Early observations have also supported the transmission of the virus via contaminated feed and water [ 11 ].…”