Mechanisms linking bovine viral diarrhea virus (BVDV) infection with infertility in cattle

Abstract

Bovine viral diarrhea virus (BVDV) is an important infectious disease agent that causes significant reproductive and economic losses in the cattle industry worldwide. Although BVDV infection is known to cause poor fertility in cattle, a greater part of the underlying mechanisms particularly associated with early reproductive losses are not clearly understood. Previous studies reported viral compromise of reproductive function in infected bulls. In females, BVDV infection is thought to be capable of killing the oocyte, embryo or fetus directly, or to induce lesions that result in fetal abortion or malformation. BVDV infections may also induce immune dysfunction, and predispose cattle to other diseases that cause poor health and fertility. Other reports also suggested BVDV-induced disruption of the reproductive endocrine system, and a disruption of leukocyte and cytokine functions in the reproductive organs. More recent studies have provided evidence of viral-induced suppression of endometrial innate immunity that may predispose to uterine disease. Furthermore, there is new evidence that BVDV may potentially disrupt the maternal recognition of pregnancy or the immune protection of the conceptus. This review brings together the previous reports with the more recent findings, and attempts to explain some of the mechanisms linking this important virus to infertility in cattle.

The Effect of Stress on Reproduction and Reproductive Technologies in Beef Cattle—A Review

“…Researchers have contributed by increasing our understanding of the factors affecting calving and conception rates in beef herds. Among the main causes of reduced reproductive efficiency in beef, we find infectious diseases [ 1 , 2 ], such as bovine viral diarrhea [ 3 , 4 ], infectious bovine rhinotracheitis [ 5 ], trichomoniasis due to Tritrichomonas foetus [ 6 , 7 ] and campilobacteriosis due to Campylobacter foetus spp. [ 6 ]; inadequate nutritional programs [ 8 ] which revealed undernutrition and imbalanced nutrition; bull infertility [ 9 ], revealing the need to confirm a bull’s breeding soundness before introducing it for natural mating in a beef herd [ 10 ]; genetics, with some aspects of reproductive performance in beef cows proving more than 50% heritable [ 11 ] and inadequate animal welfare [ 12 ].…”

Upregulation of interferon-alpha gene in bovine embryos produced in vitro in response to experimental infection with noncytophatic bovine-viral-diarrhea virus

“…Among these can be mentioned effects on reproductive organs, gametes, embryo, and fetus. Most of the mechanisms associated with early embryonic losses have however not yet been described clearly [2]. In this sense assisted reproductive techniques, and especially the in vitro production of bovine embryos used for commercial purposes, has also emerged as a useful model for primary research.…”

“…Most of the embryonic losses occur during the first days after fertilization and during the process of implantation (before days 16 to 17) and its cause is multifactorial [8]. Strong evidence suggests that infection with bovine viral diarrhea virus (BVDV) is one of many potential causes of pregnancy failure [2]. Since previous studies have demonstrated that the apoptosis and the interferon (IFN) response become manifest from the earliest stages of pregnancy [9,10], an evasion of those two key elements of the innate immune system may be crucial, not only for transmission to the fetus, but also for the maintenance of immunotolerance [9].…”

Comparison of milk production of dairy cows vaccinated with a live double deleted BVDV vaccine and non-vaccinated dairy cows cohabitating in commercial herds endemically infected with BVD virus

“…The effects of acute BVDV infection in female cows on reproductive performance have been considered to be the most costly and include reduced conception rate, embryonic death, abortion and congenital defects [8]. The underlying mechanisms of BVDV-induced infertility and reproductive disease are multifactorial, and can involve direct impacts of the virus on reproductive tissues, including the developing fetus, and indirect effects through immune system dysregulation [11]. BVDV or virus-specific antigens can be identified in reproductive tract tissues from infected cattle, and BVDV infection has been demonstrated to alter endocrine functions of reproductive tract tissues [11].…”

“…The underlying mechanisms of BVDV-induced infertility and reproductive disease are multifactorial, and can involve direct impacts of the virus on reproductive tissues, including the developing fetus, and indirect effects through immune system dysregulation [11]. BVDV or virus-specific antigens can be identified in reproductive tract tissues from infected cattle, and BVDV infection has been demonstrated to alter endocrine functions of reproductive tract tissues [11]. Indirectly, BVDV infection of naive cattle can render them more susceptible to secondary infections through immunosuppression [12].…”