Molecular detection of Bluetongue Virus (BTV) and Bovine Leukemia Virus (BLV) in uterine biopsies of dairy cows with or without reproductive problems

Abstract

Reproductive performance of dairy cows has a direct impact on herd productivity. Infectious agents, such as Bluetongue Virus (BTV) and Bovine Leukemia Virus (BLV), are associated with reproductive failure. However, it remains unknown if these viruses are present in the uterus and cause gestational loss. This study used molecular methods to assess if BTV and BLV can be detected in the uterus of serologically positive dairy cows with a record of abortions, stillbirths and repeat breeding (n=23) and without a record of reproductive problems (n =23). The cows came from three dairy herds of the state of Minas Gerais, Brazil. BTV was not detected in any of the uterine biopsies. Proviral DNA of BLV was detected in 54.5 % of the seropositive cows, but positivity for BLV in the uterus was not associated with the existence of reproductive problems. In conclusion, this study shows that BLV, but not BTV, is present in the uterus of seropositive cows, regardless of reproductive performance. Key words: Bovines. Reproduction. Uterus. BTV. BLV. associados à ocorrência de falhas reprodutivas. Entretanto, não se sabe se estes vírus poderiam estar presentes no útero resultando nas perdas gestacionais. Este estudo utilizou métodos moleculares para investigar se os vírus BTV e BLV estão presentes no úterio de vacas leiteiras sorologicamente positivas com histórico de abortos, natimortos e repetição de cio (n=23) e em vacas sem histórico de problema reprodutivos (n =23) provenientes de três rebanhos leiteiros localizados no estado de Minas Gerais, Brasil. Não foi detectado BTV em nenhuma amostra de biópsia uterina. Por outro lado, o DNA proviral de BLV foi detectado no útero de 54.5 % das vacas soropositivas, independentemente da ocorrência de problemas reprodutivos. Conclui-se que o vírus BLV, ao contrário do BTV está presente no útero de vacas soropositivas, entretanto, sem associação com o desempenho reprodutivo. Palavras-chave: Bovinos. Reprodução. Útero. BTV. BLV. Resumo

High positivity values for bovine leukemia virus in human breast cancer cases from Minas Gerais, Brazil

“…Recently, a study on the topic was published in the south of the country with results similar to those found by researchers from California (USA) and Australia, with a 31% positivity for BLV in tumor tissues and only a 14% BLV positivity in control tissues of healthy women [9]. This study was carried out concurrently with our work, but the patients in our study came from the state of Minas Gerais, southeastern Brazil, where the people are traditionally used to ingest raw (unpasteurized) milk and cheese and the prevalence of BLV in the dairy flock is very high, reaching more than 90% of the animals [15,16]. Thus, the present study aimed to determine if there is a higher association between breast cancer and the presence of BLV genome in breast tissue samples within this population that consumes raw milk from animals with high rates of BLV infection.…”

“…BLV is an oncogenic retrovirus that causes lymphoma in bovines and is closely related to the HTLV-1 that causes T-cell leukemia in humans. BLV infection occurs naturally in bovines, capybaras, and sheep, but in vitro the BLV is able to infect different cell types from a large range of species, including human cells, such as human lung embryonic cells (WI-38) and human tumor cells (ARH77 and K562) [ 14 – 16 ]. Neural origin human cells are also highly susceptible to BLV infection [ 14 ].…”