Avian influenza viruses can infect a wide variety of birds and poultry, and have been found transmissible to human beings. Waterfowls such as water birds or ducks may be carriers of avian influenza viruses. Once chickens, turkeys, or ostriches are infected, there may be a wide range of deaths. According to the current research, H5N1 has crossed the species barrier and transmitted to pigs, horses and felines (including cats, tigers, and masked palm civets).