Effect of using frozen–thawed bovine semen contaminated with lumpy skin disease virus on in vitro embryo production

Abstract

Summary Lumpy skin disease (LSD) is an important transboundary animal disease of cattle with significant economic impact because of the implications for international trade in live animals and animal products. LSD is caused by a Capripoxvirus, LSD virus (LSDV), and results in extensive hide and udder damage, fever and pneumonia. LSDV can be shed in semen of infected bulls for prolonged periods and transmitted venereally to cows at high doses. This study examined the effects of LSDV in frozen‐thawed semen on in vitro embryo production parameters, including viral status of media and resulting embryos. Bovine oocytes were harvested from abattoir‐collected ovaries and split into three experimental groups. After maturation, the oocytes were fertilized in vitro with frozen‐thawed semen spiked with a high (HD) or a lower (LD) dose of LSDV, or with LSDV‐free semen (control). Following day 7 and day 8 blastocyst evaluation, PCR and virus isolation were performed on all embryonic structures. After completing sufficient replicates to reach 1,000 inseminated oocytes, further in vitro fertilization (IVF) runs were performed to provide material for electron microscopy (EM) and embryo washing procedures. Overall, in vitro embryo yield was significantly reduced by the presence of LSDV in frozen‐thawed semen, irrespective of viral dose. When semen with a lower viral dose was used, significantly lower oocyte cleavage rates were observed. LSDV could be detected in fertilization media and all embryo structures, when higher doses of LSDV were present in the frozen‐thawed semen used for IVF. Electron microscopy demonstrated LSDV virions inside blastocysts. Following the International Embryo Transfer Society washing procedure resulted in embryos free of viral DNA; however, this may be attributable to a sampling dilution effect and should be interpreted with caution. Further research is required to better quantify the risk of LSDV transmission via assisted reproductive procedures.

Review: Vaccines and Vaccination against Lumpy Skin Disease

“…LSD risk factors that are typically evaluated for risk assessment purposes are often poorly understood. These factors should include the following risk categories: Environmental factors, such as climate and geomorphology, potentially influence arthropod vector biology [ 113 , 114 , 115 ], husbandry and biosecurity practices [ 24 , 116 , 117 ], cattle characteristics and their immune status [ 76 , 117 , 118 , 119 ], regulatory disease control and surveillance structures [ 104 , 120 ], animal- or personnel-associated movements [ 107 , 108 , 110 , 121 , 122 ], as well as societal factors [ 2 , 23 , 123 ]. Risk assessments and control of the risk factors for LSD offer valuable support in scenarios where LSD vaccination is not desired or possible for regulatory, economical, or infrastructural reasons, thus shifting from vaccination-centered disease control programs to strengthening LSD biosecurity, awareness, relevant movement regulations, and risk-based surveillance.…”

Quantifying and Modeling the Acquisition and Retention of Lumpy Skin Disease Virus by Hematophagus Insects Reveals Clinically but Not Subclinically Affected Cattle Are Promoters of Viral Transmission and Key Targets for Control of Disease Outbreaks

“…Viraemia is considered of short duration and relatively low level, though the virus can survive for longer periods of time in skin lesions (31). LSDV has also been detected in seminal fluid of diseased on May 10, 2021 by guest http://jvi.asm.org/ Downloaded from bulls (33), making venereal transmission a possibility (34)(35)(36). Subclinical infections (detection of LSDV in animals without cutaneous lesions) (3,28,32) and resistance to LSDV (absence of LSDV and cutaneous lesions following experimental challenge) have been reported, but both are poorly documented.…”

Vaccinal prevention of nodular dermatitis in Hereford cattle (clinical and immunological implications)

“…In servicing bulls, the virus may cause short-term sterility, and may be transmitted via frozen sperm during artificial insemination. In some cases, animals may die due to bacterial secondary infections [9][10][11].…”