[6] The policy of slaughter ceased in England and Wales on 31 March 1963, except for the peracute form of Newcastle disease and for fowl plague.

Transmission occurs by exposure to faecal and other excretions from infected birds, and through contact with contaminated food, water, equipment, and clothing.

High concentrations of the NDV are found in birds' bodily discharges; therefore, the disease can be spread easily by mechanical means.

NDV can survive for several weeks in a warm and humid environment on birds' feathers, manure, and other materials.

Smuggled pet birds, especially Amazon parrots from Latin America, pose a great risk of introducing NDV into the US.

Signs of infection with NDV vary greatly depending on factors such as the strain of virus and the health, age and species of the host.

In flocks with good immunity, however, the signs (respiratory and digestive) are mild and progressive, and are followed after seven days by nervous symptoms, especially twisted heads.

[citation needed] Petechiae in the proventriculus and on the submucosae of the gizzard are typical; also, severe enteritis of the duodenum occurs.

[17] Schiappacasse et al. 2020 demonstrates successful, complete inactivation of the virus in a space using a nonthermal plasma generator.

[18] Though the oncolytic effect of NDV was already documented in the 1950s, later advances in research into using viruses in cancer therapy came with the advent of reverse genetics technologies.

[19][22] As of 2018[update] there had been several clinical studies into the use of NDV for cancer treatment, but the research quality was low and the outcomes inconclusive.