ORIGINAL_ARTICLE Sero-prevalence of bovine leukemia virus infection in Kosovo cattle A cross-sectional survey was conducted in Kosovo to determine the presence and prevalence of bovine leukemia virus antibodies in cattle. A total of 5,051 serum samples from 315 villages were collected during 2016. Samples were tested using commercial indirect enzyme-linked immunosorbent assay. At least one sero-positive animal was found in 55 (17.5%) of the villages sampled, of which 23 had more than one sero-positive detected. Overall individual sero-prevalence, corrected for geographic distribution of samples, was found to be 2.26% (95% c.i. 1.62% to 3.04%). There were no statistically significant associations between serological status and herd size or age of animal, although sero-prevalence in 5-year-old cattle was higher than in the other ages. There was a statistical significant heterogeneity in sero-prevalence between different geographic zones of Kosovo (chi‐square value = 20.68 (4 d.f.); (p=0.0004). Pairwise comparisons showed that sero‐prevalence in the south was significantly higher than in the east and in the north and sero‐prevalence in the west was significantly higher than in the north. The 3.11% aggregated sero-prevalence for the two highest sero-prevalence zones, south and west, was significantly higher than the 1.57% aggregated sero-prevalence for the remaining zones, centre, east and north (Fisher exact p‐value (2‐tail) = 0.0004). The reason for higher prevalence in the south and west of Kosovo is uncertain. These results may serve to enrich the information of bovine leukemia virus distribution in the region, as well as a starting point for the future control and eradication strategy in Kosovo. https://macvetrev.mk/Files/Article/2020/10.2478/macvetrev-2020-0030/macvetrev-2020-0030.pdf 2020-10-15T09:00:00 175 183 10.2478/macvetrev-2020-0030 bovine leukemia virus epidemiology sero-prevalence Kosovo Valdet Gjinovci false 1 Faculty of Food Technology, University of Mitrovica, Kosovo AUTHOR Armend Cana armend.cana@rks-gov.net false 2 Sector of Serology and Molecular Diagnostics, Kosovo Food and Veterinary Laboratory, Kosovo Food and Veterinary Agency, Str Lidhja e Pejes, Prishtina 10000, Kosovo LEAD_AUTHOR Mentor Alishani false 3 Faculty of Agriculture and Veterinary, University of Prishtina, Kosovo AUTHOR Dafina Mehmetukaj false 4 Sector of Serology and Molecular Diagnostics, Kosovo Food and Veterinary Laboratory, Kosovo Food and Veterinary Agency, Str Lidhja e Pejes, Prishtina 10000, Kosovo AUTHOR Nick Taylor false 5 Veterinary Epidemiology and Economics Research Unit (VEERU) & PAN Livestock Services Ltd., University of Reading, School of Agriculture, Policy and Development, Reading, RG6 6AR, United Kingdom AUTHOR Naomi Honhold false 6 Department of Public Health, NHS Lothian, Edinburgh, United Kingdom AUTHOR Polat, M., Takeshima, Sh.N., Aida, Y. (2017). Epidemiology and genetic diversity of bovine leukemia virus. Virol J. 14(1): 209. PMid:29096657 PMCid:PMC5669023 1 10.1186/s12985-017-0876-4 Hopkins, S.G., Digiacomo, R.F. (1997). Natural transmission of bovine leukemia virus in dairy and beef cattle. Vet Clin North Am Food Anim Pract. 13(1): 107-128. 2 10.1016/S0749-0720(15)30367-4 Panei, C.J., Larsen, A.E., Fuentealba, N.A., Metz, G.E., Echeverría, M.G., Galosi, C.M., Valera, A.R. (2019). Study of horn flies as vectors of bovine leukemia virus. Open Vet J. 9(1): 33-37. PMid:31086763 PMCid:PMC6500860 3 10.4314/ovj.v9i1.6 Kohara, J., Takeuchi, M., Hirano, Y., Sakurai, Y., Takahashi, T. (2018). Vector control efficacy of fly nets on preventing bovine leukemia virus transmission. J Vet Med Sci. 80(10): 1524-1527. PMid:30122691 PMCid:PMC6207509 4 10.1292/jvms.18-0199 Ruiz, V., Porta, N.G., Lomonaco, M., Trono, K., Alvarez, I. (2018). Bovine leukemia virus infection in neonatal calves. Risk factors and control measures. Front Vet Sci. 5, 267. PMid:30410920 PMCid:PMC6209627 5 10.3389/fvets.2018.00267 Nagy, D.W., Tyler, J.W., Kleiboeker, S.B. (2007). Decreased periparturient transmission of bovine leukosis virus in colostrum-fed calves. J Vet Intern Med. 21(5): 1104-1107. PMid:17939571 6 10.1111/j.1939-1676.2007.tb03071.x Nekouei, O., Vanleeuwen, J., Stryhn, H., Kelton, D., Keefe, G. (2016). Lifetime effects of infection with bovine leukemia virus on longevity and milk production of dairy cows. Prev Vet Med. 133, 1-9. PMid:27720022 7 10.1016/j.prevetmed.2016.09.011 Erskine, J.R., Bartlett, P.T., Byrem, T.M., Render, C.L., Febvey, C., Houseman, J.T. (2012). Association between bovine leukemia virus, production, and population age in Michigan dairy herds. J Dairy Sci. 95(2): 727-734. PMid:22281337 8 10.3168/jds.2011-4760 Pezler, K. D (1997). Economics of bovine leukemia virus infection. Vet Clin North Am Food Anim Pract. 13(1): 129-141. 9 10.1016/S0749-0720(15)30368-6 Otto, S.L., Johnson, R., Wells, S.J. (2003). Association between bovine-leukosis virus seroprevalence and herd-level productivity on US dairy farms. Prev Vet Med. 61(4): 249-261. PMid:14623410 10 10.1016/j.prevetmed.2003.08.003 OIE. Manual of Diagnostic Tests and Vaccines for Terrestrial Animals. Vol. Chapter 3.4.9. 2019. 11 Kuczewski, A., Orsel, K, Barkema, H.W., Kelton, D.F., Hutchins, W.A., Van Der Meer, F. (2018). Short communication: Evaluation of five different ELISA for the detection of bovine leukemia virus antibodies. J Dairy Sci. 101(3): 2433-2437. PMid:29274963 12 10.3168/jds.2017-13626 Sandev, N., Ilieva, D., Sizov, I., Rusenova, N., Iliev, E. (2006). Prevalence of enzootic bovine leukosis in the Republic of Bulgaria in 1997-2004. Vet Arhiv. 76(3): 263-268. 13 Bennett, S., Woods, T., Liyanage, W.M., Smith, D.L. (1991). A simplified general method for cluster-sample surveys of health in developing countries. World Health Stat. Q. 44(3): 98-106. 14 Commission of the European Communities: European Commission Decision of 15 December 2009 amending Annex D to Council Directive 64/432/EEC as regards the diagnostic tests for enzootic bovine leucosis (2009/976/EU)." Official Journal of the European Union 336 (n.d.): 36-41. 15 Dean, A.G., Sullivan, K.M., Soe, M.M. OpenEpi: Open source epidemiologic statistics for public health. Version. Updated 2013. Available at: http://openepi.com/Menu/OE_Menu.htm. 16 Wilson, E.B., (1927). Probable inference, the law of succession, and statistical inference. Journal of the American Statistical Association 22(158): 209-212. 17 10.1080/01621459.1927.10502953 Rothman, K.J., Boice, J.D.Jr. (1979). Epidemiologic analysis with a programmable calculator. NIH Pub No. 79‐1649. Bethesda, MD: National Institutes of Health, pp. 31-32. 18 Wallis, S. (2013). Binomial confidence intervals and contingency tests: mathematical fundamentals. JQL. 20(3): 178‐208. 19 10.1080/09296174.2013.799918 Cannon, R.M., Roe, R.T. (1982). Livestock disease surveys. A field manual for veterinarians. National government publication. Bureau of rural science, Department of primary industry. Australian Government Publishing Service, Canberra, pp 14. 20 Şevik, M., Avci, O., Ince, O.B. (2015). An 8-year longitudinal sero-epidemiological study of bovine leukaemia virus (BLV) infection in dairy cattle in Turkey and analysis of risk factors associated with BLV seropositivity. Trop Anim Health Prod. 47(4): 715-720. PMid:25708566 21 10.1007/s11250-015-0783-x Murakami, K., Kobayashi, S., Konishi, M., Yamamoto, T., Tsutsui, T. (2011). The recent prevalence of bovine leukemia virus (BLV) infection among Japanese cattle. Vet Microbiol. 148(1): 84-88. PMid:20832956 22 10.1016/j.vetmic.2010.08.001 Frie, M.C., Coussens, P.M. (2015). Bovine leukemia virus: A major silent threat to proper immune responses in cattle. Vet Immunol Immunopathol. 163(3-4): 103-114. PMid:25554478 23 10.1016/j.vetimm.2014.11.014 Wu, M.C., Shanks, R.D., Lewin, H.A. (1989). Milk and fat production in dairy cattle influenced by advanced subclinical bovine leukemia virus infection. Proc Natl Acad Sci. USA. 86(3): 993-996. PMid:2536940 PMCid:PMC286605 24 10.1073/pnas.86.3.993 Yang, Y., Fan, W., Mao, Y., Yang, Z., Lu, G., Zhang, R., Zhang, H., Szeto, C., Wang, C. (2016). Bovine leukemia virus infection in cattle of China: Association with reduced milk production and increased somatic cell score. J Dairy Sci. 99(5): 3688-3697. PMid:26923050 25 10.3168/jds.2015-10580 Oltenacu, P.A., Algers, B. (2005). Selection for increased production and the welfare of dairy cows: are new breeding goals needed? Ambio. 34(4-5): 311-315. PMid:16092261 26 10.1579/0044-7447-34.4.311 Ladronka, R.M., Ainsworth, S., Wilkins, M.J., Norby, B., Byrem, T.M., Bartlett, P.C. (2018). Prevalence of bovine leukemia virus antibodies in US dairy cattle. Vet Med Int. 4, 1-8 PMid:30534354 PMCid:PMC6252197 27 10.1155/2018/5831278