Canine Blood Group Prevalence and Geographical Distribution around the World: An Updated Systematic Review

“Blood group” or “blood type” refers to the blood group system comprising red blood cell antigens and a specific pattern. Many studies have characterized dog blood groups by the prevalence of the Dog Erythrocyte Antigen (DEA), Kai, and Dal antigens in different geographic areas and by using a variety of methods. Some pioneering studies on blood groups, upon which others were subsequently based, were conducted by Bowdler, Colling, and Hall in the 1970s and 1980s. Our results show that most relevant studies covered the European and American continents, and the methods used to identify DEA, Kai, and Dal groups evolved from 1999 to 2020, albeit without a single method based upon specificity and sensitivity. However, the existence of rapid commercial kits for the determination of the DEA 1 group makes this group the most widely used in clinical practice. Through a systematic review, our aim was to illustrate the countries in the world where different blood groups have been identified with reference to the different methods used and the prevalence of those groups among dog breeds.