Selection of ligand peptides with the ability to detect antibodies in enzootic bovine leukosis

Peptides present in phages were selected using phage display technology and immunoassays to find out the antigenic mimetics of immunodominant epitopes of bovine leukosis virus (BLV). The use of antigenic mimetics may result in the enhancement of the sensitivity and specificity of the serologic diagnosis of enzootic bovine leukosis (EBL), contributing directly to disease control. The selections enabled the choice of clones which can be used as potential antigens in the diagnoses of diseases. The synthetic peptide produced from the selected sequences may be considered as an alternative for antigens in the serologic diagnosis of enzootic bovine leukosis.Key words: Diagnostic, antigens, enzootic bovine leukosis (EBL), phage display

Utjecaj virusa enzootske leukoze goveda na pojavu supkliničkog mastitisa u krava u različitim stupnjevima infekcije.

Studies were performed on 26 cows, divided into 3 groups on the basis of serological (by immunodiffusion test) and haematological analyses for bovine leukosis: Group I - seropositive without changes in haemogram; group II - seropositive with changes in haemogram and group III (control) - BLV negative. A statistically significant difference was observed in the incidence of subclinical mastitis in cows from group II (P<0.05) compared to healthy animals. The most commonly isolated microorganism was S. agalactiae (46.80%), followed by Staphylococcus spp. (36.06%). The results of our studies, as well as data from other investigators evidenced that the incidence of subclinical mastitis was higher in cows with changes in the white blood cell picture due to the immunosuppressive effect of the enzootic bovine leukosis virus.Istraživanje je provedeno na 26 krava podijeljenih u tri skupine na osnovi seroloških (imunodifuzijski test) i hematoloških pretraga na leukozu goveda. U prvoj skupini bile su serološki pozitivne krave bez promjena u hemogramu. U drugoj skupini bile su serološki pozitivne krave s promijenjenim hemogramom, a u trećoj kontrolnoj skupini bile su krave serološki negativne za virus enzootske leukoze goveda. Statistički značajna razlika u pojavi supkliničkog mastitisa u usporedbi sa zdravim kravama dokazana je u krava druge skupine (P<0,05). Najčešće izdvojena bakterija bila je S. agalactiae (46,80%) te Staphylococcus spp. (36,06%). Rezultati istraživanja potvrđuju da je pojava mastitisa bila češća u krava s poremećajima u bijeloj krvnoj slici, što se pripisuje učinku virusa enzootske leukoze goveda

Utjecaj virusa enzootske leukoze goveda na pojavu supkliničkog mastitisa u krava u različitim stupnjevima infekcije.

Studies were performed on 26 cows, divided into 3 groups on the basis of serological (by immunodiffusion test) and haematological analyses for bovine leukosis: Group I - seropositive without changes in haemogram; group II - seropositive with changes in haemogram and group III (control) - BLV negative. A statistically significant difference was observed in the incidence of subclinical mastitis in cows from group II (P<0.05) compared to healthy animals. The most commonly isolated microorganism was S. agalactiae (46.80%), followed by Staphylococcus spp. (36.06%). The results of our studies, as well as data from other investigators evidenced that the incidence of subclinical mastitis was higher in cows with changes in the white blood cell picture due to the immunosuppressive effect of the enzootic bovine leukosis virus.Istraživanje je provedeno na 26 krava podijeljenih u tri skupine na osnovi seroloških (imunodifuzijski test) i hematoloških pretraga na leukozu goveda. U prvoj skupini bile su serološki pozitivne krave bez promjena u hemogramu. U drugoj skupini bile su serološki pozitivne krave s promijenjenim hemogramom, a u trećoj kontrolnoj skupini bile su krave serološki negativne za virus enzootske leukoze goveda. Statistički značajna razlika u pojavi supkliničkog mastitisa u usporedbi sa zdravim kravama dokazana je u krava druge skupine (P<0,05). Najčešće izdvojena bakterija bila je S. agalactiae (46,80%) te Staphylococcus spp. (36,06%). Rezultati istraživanja potvrđuju da je pojava mastitisa bila češća u krava s poremećajima u bijeloj krvnoj slici, što se pripisuje učinku virusa enzootske leukoze goveda

Prevalence of enzootic bovine leukosis in the Republic of Bulgaria in 1997-2004

The serological investigations using the agar gel immunodiffusion (AGID) test performed in the Republic of Bulgaria in the period 1997-2004 showed a high prevalence of enzootic bovine leukosis (EBL), from 8.47% in 1997 to 22.26% in 2004. The highest percentage of seroreagents was observed in the regions of Silistra (48.61%), Dobrich (47.57%) and Burgas (47.32%), with the lowest, in the regions of Pazardjik (0.28%), Kyustendil (1.89%) and Smolyan (1.95%). Leukosis infection was found to be more prevalent in Eastern than in Western Bulgaria. The total EBL epidemic foci in 2004 numbered more than 600.Depending on the severity of the epidemiological process, the eradication of leukosis in the country could be achieved in 5 to 10 years with sufficient financial funding and strict realization of the National programme for prophylaxis and control of EBL

Assessment of listing and categorisation of animal diseases within the framework of the Animal Health Law (Regulation (EU) No 2016/429): enzootic bovine leukosis (EBL)

Non peer reviewe

Preventive and Therapeutic Strategies for Bovine Leukemia Virus: Lessons for HTLV

Bovine leukemia virus (BLV) is a retrovirus closely related to the human T-lymphotropic virus type 1 (HTLV-1). BLV is a major animal health problem worldwide causing important economic losses. A series of attempts were developed to reduce prevalence, chiefly by eradication of infected cattle, segregation of BLV-free animals and vaccination. Although having been instrumental in regions such as the EU, these strategies were unsuccessful elsewhere mainly due to economic costs, management restrictions and lack of an efficient vaccine. This review, which summarizes the different attempts previously developed to decrease seroprevalence of BLV, may be informative for management of HTLV-1 infection. We also propose a new approach based on competitive infection with virus deletants aiming at reducing proviral loads

Parálisis posterior en una vaca Holstein con Leucosis Enzoótica Bovina

ABSTRACT: A 6 year-old Holstein cow was euthanized after a 3 week course of progressive paraplegia. In spite of the increasing difficulties to rise and walk, the animal remained bright, alert, afebrile and with good appetite throughout most of the clinical course. Complete blood counts, biochemical profiles and analysis of the cerebrospinal fluid were reported within normal limits. Antibody was detected for bovine leukaemia virus using an enzyme-linked immunosorbent assay, supporting a tentative diagnosis of bovine leukosis. Post-mortem examination revealed a localized form of lymphosarcoma with few 2-5 cm nodular tumors confined to the walls of the gastrointestinal tract, particularly in the abomasum. In addition, soft grey tumors were found within the vertebral canal surrounding the lumbar spinal cord and associated nerve roots. Microscopic examination revealed the nodular masses were composed of neoplastic lymphocytes. Mass in the lumbar vertebral canal had extradural neoplastic lymphocytes infiltrating connective tissues around the spinal cord and spinal nerve roots. Unlike the more common chronic and wasting presentation of the disease with widespread lymphadenopathy, the rapid progression of the disease to total paraplegia in this animal could be explained by the localized presence of tumors in the spinal canal.RESUMEN: Una vaca Holstein de 6 años de edad fue sacrificada después de un curso de paraplejía progresiva de 3 semanas de duración. A pesar de las crecientes dificultades para levantarse y caminar, el animal se mantuvo alerta, sin fiebre y con buen apetito casi todo el transcurso de la enfermedad. Los análisis del hemograma, perfil bioquímico y líquido cefalorraquídeo no mostraron alteraciones fuera del rango normal. El análisis de ELISA frente al virus de la Leucosis Bovina resultó positivo, apoyando el diagnóstico diferencial de leucemia. El examen post-mortem reveló una forma localizada de linfosarcoma, con escasas y pequeñas tumoraciones nodulares de 2-5 cm confinadas a las paredes del tracto gastrointestinal, sobre todo en el abomaso. Además, los tumores estaban presentes en el canal vertebral rodeando la médula lumbar espinal y raíces nerviosas adyacentes. El examen microscópico reveló que las masas nodulares estaban compuestas de linfocitos neoplásicos; igualmente, el tejido conectivo rodeando la medula lumbar presentaba gran infiltración de dichos linfocitos. A diferencia de la presentación más corriente y crónica de la enfermedad en que existe un desgaste progresivo del animal asociado a una linfadenopatía generalizada, en este caso la rápida progresión de la enfermedad hacia una paraplejia total se podría explicar por la presencia de tumores localizados en el canal espinal

Use of the Polymerase Chain Reaction in the Detection of Bovine Leukosis

A diagnostic test for bovine leukosis was developed using the polymerase chain reaction (PCR) to amplify a 375 base pair region in the gag gene of the proviral genome. Blood samples were collected from 3 adult Holstein cows shown to be infected with bovine leukosis virus (BLV) by the agar-gel immunodiffusion (AGID) technique. The 3 samples were mixed and the composite blood was used to inoculate 10 cows. Five of the cows were inoculated with 0.1 ml of blood, and the other cows were inoculated with 1 ml of blood. Five of the cows were negative for BLV by AGID and PCR on the day of inoculation, and the other five cows were positive for BLV on the day of inoculation. The 10 cows were bled on day 1 (day 0 being the day of inoculation) and day 7 post-inoculation, and every 2 weeks subsequently until 3 months post-inoculation. Samples were stored until the end of the study, at which time the AGID and PCR tests were performed. Three cows became AGID-positive 3 weeks post-inoculation, and two cows seroconverted 5 weeks post-inoculation. The time of seroconversion did not correlate with the volume of viral inoculum. In comparison, the PCR consistently detected infection sooner than the AGID: by day 7 post-inoculation all 5 cows were BLV-positive as determined with the PCR test, and remained positive until the end of the study. The results indicate that under the experimental conditions, bovine leukemia virus infection in cattle can be detected as much as 2 to 4 weeks earlier by PCR than by AGID