Origin of the domestic dog or the result of natural introgression as the dog expanded across Eurasia. In 2018, a study found a small amount of dog ancestry in 62% of Eurasian wolf specimens looked at, that hybridization had occurred across a wide number of timescales and not just recently, however in contrast there was almost no admixture detected in the North American specimens. There was introgression of the male dog into the wolf, but also one hybrid detected which was the result of a male wolf crossed with a female dog. Wolves have maintained their phenotype differences from the dog, which indicates low-frequency hybridization.
Ticks of domestic animals create a potentially fatal inflammatory crisis of the blood. The name redwater (coloured urine) derives from the hemoglobinuria caused by the destruction of red blood cells infected with the merozoite stage of "Babesia"; anemia results from the same destruction. Horses suffer babesiosis or biliary fever when infected by "Ba. equi" or "B. caballi". This occurs in many countries where vector ticks are found, such as "R. e. evertsi", "Hy. truncatum", and "D. nitens". Dogs are at risk from severe infection with "Ba. canis" and its subspecies, transmitted by the dog ticks "R. sanguineus", "D. reticulatus", and "Ha. leachi". Domestic cats