Veterinary medicine is the branch of medicine that deals with the prevention, diagnosis and treatment of disease, disorder and injury in animals. The scope of veterinary medicine is wide, covering all animal species, both domesticated and wild, with a wide range of conditions which can affect different species. Veterinary medicine is widely practiced, both with and without professional supervision. Professional care is most often led by a veterinary physician (also known as a vet, veterinary surgeon or veterinarian), but also by paraveterinary workers such as veterinary nurses or technicians. This can be augmented by other paraprofessionals with specific specialisms such as animal physiotherapy or dentistry, and species relevant roles such as farriers. Veterinary science helps human health through the monitoring and control of zoonotic disease (infectious disease transmitted from non-human animals to humans), food safety, and indirectly through human applications from basic medical research. They also help to maintain food supply through livestock health monitoring and treatment, and mental health by keeping pets healthy and long living. Veterinary scientists often collaborate with epidemiologists, and other health or natural scientists depending on type of work. Ethically, veterinarians are usually obliged to look after animal welfare.