Why in news?
In October 2025, Florida wildlife officials confirmed the state’s second case of chronic wasting disease (CWD) in a white‑tailed deer found dead near the Alabama border. CWD, sometimes dubbed “zombie deer disease”, is a contagious and fatal neurological disorder affecting members of the deer family. The discovery prompted the Florida Fish and Wildlife Conservation Commission to expand surveillance and advise hunters on safe carcass disposal.
Background
Chronic wasting disease is caused by abnormal, self‑replicating proteins known as prions. First identified in captive mule deer in Colorado in the 1960s, CWD belongs to the same group of neurodegenerative disorders as mad cow disease and scrapie. It has since spread to wild and captive populations of deer, elk, moose and reindeer in over thirty U.S. states and parts of Canada, Scandinavia and South Korea. The disease has a 100 % mortality rate in animals but has not been documented in humans.
How CWD spreads
- Direct and environmental transmission: Infectious prions are shed in saliva, urine, faeces, blood and antler velvet. Healthy animals contract the disease through nose‑to‑nose contact with infected individuals or by grazing on contaminated soil and plants. Prions persist in the environment for years.
- Long incubation: Signs may not appear for 18–24 months after infection. During this period, animals look normal but can spread prions to others.
- Geographical expansion: The disease spreads when infected deer or carcasses are moved to new areas, or when natural migration brings healthy animals into contaminated zones.
Symptoms and outcome
- Physical decline: The most obvious sign is progressive weight loss. Affected animals may develop a hunched posture and drooping ears.
- Behavioural changes: Infected deer become listless, show reduced fear of humans, drool excessively and drink and urinate more. Neurological signs include uncoordinated movement, tremors and stumbling.
- Fatal prognosis: Once symptoms appear, animals decline rapidly and die. There is no vaccine or treatment.
Risk to humans and management
To date, no human cases of CWD have been confirmed. However, health agencies recommend that hunters avoid consuming meat from sick animals and have harvested deer tested where the disease is present. Management strategies include banning supplemental feeding (which encourages close contact), restricting the movement of carcasses and reducing deer densities in affected areas. Ongoing research aims to better understand the risk of species jumps and to develop diagnostic tools.
Source: The Guardian · TN · Centers for Disease Control and Prevention