Ovine pulmonary adenocarcinoma be predisposed to OPA. Most affected sheep show signs at 2 to 4 years of age. OPA is not a notifiable disease, and therefore it is difficult to assess its prevalence. OPA was first described in the UK in 1888, and described in detail in South Africa in 1891. The disease was initially known as "jaagsiekte" , a word derived from Afrikaans, meaning "chasing sickness," so called because animals are in respiratory distress as if they are out of breath from being chased. It has also been known as sheep pulmonary adenomatosis and ovine pulmonary carcinoma. OPA has been used
Animal studies of Natural History showed family groupings that conformed to the traditional human nuclear family, which misrepresented the animals' observed behavior in the wild. Critical approaches in animal studies have also considered representations of non-human animals in popular culture, including species diversity in animated films. By highlighting these issues, animal studies strives to re-examine traditional ethical, political, and epistemological categories in the context of a renewed attention to and respect for animal life. The assumption that focusing on animals might clarify human knowledge is neatly expressed in Claude Lévi-Strauss's famous dictum that animals are "good to think." Animal studies Animal studies