Intrauterine infection with bovine leukemia virus in pregnant dam with high viral load

Sajiki, Yamato; Konnai, Satoru; Nishimori, Asami; Okagawa, Tomohiro; Maekawa, Naoya; Goto, Shintaro; Nagano, Masashi; Kohara, Junko; Kitano, Nana; Takahashi, Toshihiko; Tajima, Motoshi; Mekata, Hirohisa; Horii, Yoichiro; Shiro, Motoo; Ohashi, Kazuhiko

doi:10.1292/jvms.17-0391

Cited by 24 publications

(21 citation statements)

References 15 publications

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“…Nonetheless, calves can generally acquire BLV from their dams through vertical transmission (Meas et al, 2002;Mekata et al, 2015). This was confirmed in a report (Sajiki et al, 2017) that BLV genomic sequences were identical in Holstein dams and their infected calves. Additionally, a cow's BLV proviral load influences rate of transmission to her calf.…”

Section: Vertical Transmissionsupporting

confidence: 53%

“…Additionally, implementation of single-use needles for injections did not reduce risk of new seroconversions Fukai et al, 1999;Meas et al, 2002;Mekata et al, 2015;Sajiki et al, 2017 Colostrum, milk Detection of BLV in colostrum and milk of BLV-positive cows Transmission possible for milk and colostrum Calf's age could have protective effect Protective effect of colostrum antibodies Transmission of BLV through colostrum and milk is possible (0-100%) Possible protective effect of colostrum from BLV-positive dams Freezing-thawing seems to inhibit infectivity of colostrum Meas et al, 2002;Nagy et al, 2007;Kanno et al, 2014;Ruiz et al, 2018 1 Summary of experimental studies after Hopkins and DiGiacomo (1997). Results of risk analysis models are not included.…”

Section: Horizontal Transmissionmentioning

confidence: 97%

“…In 2 studies, dairy and beef cows with a high proviral load (>400 copies/10 ng of DNA or >3,000 copies/50 ng of DNA) were more likely to transmit BLV to their calves than those with a lower proviral load (<400 copies/10 ng of DNA or ≤10 copies/50 ng of DNA). Specifically, 14/29 and 4/4 calves were infected in the high proviral load groups versus 9/95 and 0/2 calves infected in the low proviral load groups (Mekata et al, 2015;Sajiki et al, 2017). Effects of proviral loads on likelihood of transmission could explain contradictory findings regarding vertical transmission of BLV (Hopkins and DiGiacomo, 1997).…”

Section: Vertical Transmissionmentioning

confidence: 99%

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Invited review: Bovine leukemia virus—Transmission, control, and eradication

Kuczewski

Orsel

Barkema

et al. 2021

Journal of Dairy Science

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Bovine leukemia virus (BLV) infection, endemic in North American dairy herds, has production-limiting effects. A literature review of available papers published since 1995 concerning BLV transmission and its control was conducted. Although confirmed transmission routes were reviewed (blood, natural breeding, in utero, colostrum, and milk), there is still a lack of detailed information on other specific risks for transmission (e.g., contact transmission and hoof-trimming knives). Eradication of BLV has been achieved by combined management, segregation, and culling approaches. In contrast, although sole implementation of best management practices aimed at prevention of BLV transmission has decreased within-herd BLV prevalence, it has not eradicated BLV from a herd. Therefore, control and eradication of BLV by best management practices only should be further investigated. Additionally, the role of proviral load in infected cattle was investigated. Cattle with a high proviral load seem to be more likely to infect others, whereas those with a very low proviral load seem to have low risks of transmitting BLV. Information on proviral load could be taken into account when controlling BLV in high-prevalence herds. In conclusion, there is a need for detailed, large-scale studies investigating roles of specific transmission routes, knowing proviral load of infected individuals.

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Section: Vertical Transmissionsupporting

confidence: 53%

Section: Horizontal Transmissionmentioning

confidence: 97%

Section: Vertical Transmissionmentioning

confidence: 99%

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Invited review: Bovine leukemia virus—Transmission, control, and eradication

Kuczewski

Orsel

Barkema

et al. 2021

Journal of Dairy Science

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“…Monotherapy with anti-PD-L1 chAb had no impact on BLV-infected cattle with high proviral load (animal #6), but combined treatment of animal #3 with the COX-2 inhibitor plus anti-PD-L1 chAb substantially reduced BLV proviral load to below 2000 copies/50 ng DNA from day 7 to day 49 after the first injection. Previous studies have demonstrated that BLV proviral load is positively correlated with vertical and horizontal transmission risks, and BLV-infected cattle with a high proviral load (.2000 copies/50 ng DNA) are the major source of transmission within a herd (26,51,52). Therefore, our findings suggest that the cotargeting of PGE 2 and PD-L1 in the most severely infected animals could be a novel method for herd BLV infection control.…”

Section: Discussionmentioning

confidence: 61%

Prostaglandin E2–Induced Immune Exhaustion and Enhancement of Antiviral Effects by Anti–PD-L1 Antibody Combined with COX-2 Inhibitor in Bovine Leukemia Virus Infection

Sajiki

Konnai

Okagawa

et al. 2019

The Journal of Immunology

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Bovine leukemia virus (BLV) infection is a chronic viral infection of cattle and endemic in many countries, including Japan. Our previous study demonstrated that PGE 2 , a product of cyclooxygenase (COX) 2, suppresses Th1 responses in cattle and contributes to the progression of Johne disease, a chronic bacterial infection in cattle. However, little information is available on the association of PGE 2 with chronic viral infection. Thus, we analyzed the changes in plasma PGE 2 concentration during BLV infection and its effects on proviral load, viral gene transcription, Th1 responses, and disease progression. Both COX2 expression by PBMCs and plasma PGE 2 concentration were higher in the infected cattle compared with uninfected cattle, and plasma PGE 2 concentration was positively correlated with the proviral load. BLV Ag exposure also directly enhanced PGE 2 production by PBMCs. Transcription of BLV genes was activated via PGE 2 receptors EP2 and EP4, further suggesting that PGE 2 contributes to disease progression. In contrast, inhibition of PGE 2 production using a COX-2 inhibitor activated BLV-specific Th1 responses in vitro, as evidenced by enhanced T cell proliferation and Th1 cytokine production, and reduced BLV proviral load in vivo. Combined treatment with the COX-2 inhibitor meloxicam and anti-programmed death-ligand 1 Ab significantly reduced the BLV proviral load, suggesting a potential as a novel control method against BLV infection. Further studies using a larger number of animals are required to support the efficacy of this treatment for clinical application.

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“…Experimental infection of cows during pregnancy has also been found to result in seropositive calves at birth, indicating that calves had been infected in utero ( 56 ). Recently, Sajiki et al ( 57 ) reported the direct evidence of intrauterine infection in two pregnant dams with a high proviral load (PVL). These authors detected BLV DNA in both of the newborns delivered via cesarean section by nested PCR, and found that the amplified BLV- env gene sequences from the dams and the newborns were completely identical.…”

Section: Transmissionmentioning

confidence: 99%

Bovine Leukemia Virus Infection in Neonatal Calves. Risk Factors and Control Measures

et al. 2018

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Bovine leukemia virus (BLV) is the causative agent of enzootic bovine leukosis (EBL). Although efficient eradication programs have been successfully implemented in most European countries and Oceania, BLV infection rates are still high worldwide. BLV naturally infects cattle, inducing a persistent infection with diverse clinical outcomes. The virus infects lymphocytes and integrates a DNA intermediate as a provirus into the genome of the cells. Therefore, exposure to biological fluids contaminated with infected lymphocytes potentially spreads the virus. Vertical transmission may occur in utero or during delivery, and about 10% of calves born to BLV-infected dams are already infected at birth. Most frequently, transmission from dams to their offspring occurs through the ingestion of infected colostrum or milk. Therefore, although EBL is not a disease specific to the neonatal period, during this period the calves are at special risk of becoming infected, especially in dairy farms, where they ingest colostrum and/or raw milk either naturally or artificially. Calves infected during the first week of life could play an active role in early propagation of BLV to susceptible animals. This review discusses the main factors that contribute to neonatal BLV infection in dairy herds, as well as different approaches and management practices that could be implemented to reduce the risk of BLV transmission during this period, aiming to decrease BLV infection in dairy herds.

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Intrauterine infection with bovine leukemia virus in pregnant dam with high viral load

Cited by 24 publications

References 15 publications

Invited review: Bovine leukemia virus—Transmission, control, and eradication

Invited review: Bovine leukemia virus—Transmission, control, and eradication

Prostaglandin E2–Induced Immune Exhaustion and Enhancement of Antiviral Effects by Anti–PD-L1 Antibody Combined with COX-2 Inhibitor in Bovine Leukemia Virus Infection

Bovine Leukemia Virus Infection in Neonatal Calves. Risk Factors and Control Measures

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