Vaccinations exist for both rabbit hemorrhagic disease and myxomatosis. Cottontail rabbits show a greater resistance to myxomatosis than European rabbits. Today's remaining feral rabbits in Australia are largely immune to myxomatosis. Myxomatosis can also infect pet rabbits (the same species). The myxomatosis virus was released in 1950 to reduce pest rabbit numbers. Respiratory symptoms are a common finding in rabbits that survive the first stages of myxomatosis. The virus created strong selection pressure for the evolution of rabbits resistant to myxomatosis. It can act as a vector for the virus that causes the rabbit disease myxomatosis. Fleas can transmit "Rickettsia typhi", "Rickettsia felis", "Bartonella henselae", and the myxomatosis virus. Lockley used Orielton for biological research, including into the rabbit disease myxomatosis. Myxomatosis is spread by biting insects, including mosquitoes. During this time he oversaw the release of myxomatosis for rabbit control in Australia. In some countries, annual vaccinations against myxomatosis are available. The vaccine has been shown to reduce mortality and clinical signs of myxomatosis. Vaccines against myxomatosis are available in some countries.