distemper

Distemper is a contagious viral disease primarily affecting dogs, caused by canine distemper virus (CDV), a morbillivirus in the Paramyxoviridae family. The virus infects multiple organ systems, including the lymphoid tissue, respiratory and gastrointestinal tracts, skin, and nervous system, leading to a multisystemic illness. CDV can also infect a range of other carnivores, such as ferrets, foxes, raccoons, and some big cats.

Transmission occurs mainly through aerosols from coughing or sneezing, but the virus may also be shed in urine, feces, and nasal discharges. Animals are often infectious before clinical signs appear. Young, unvaccinated animals are at the highest risk, and outbreaks can affect both households and wildlife populations.

Clinical signs vary and may appear in stages. Early symptoms include fever, nasal and ocular discharge, coughing, lethargy, and loss of appetite. Gastrointestinal signs such as vomiting and diarrhea can occur. As the disease progresses, secondary infections due to immune suppression may develop, and neurological signs—such as tremors, seizures, ataxia, and myoclonus—can occur. Chronic cases may show hardening of the footpads (hyperkeratosis).

Diagnosis is based on clinical signs, history, and laboratory tests. Laboratory methods include PCR testing on blood, nasal or ocular swabs, or urine; virus isolation or serology can support the diagnosis. In suspected neurologic cases, additional imaging and cerebrospinal fluid analysis may be used.

There is no curative treatment for CDV; management is supportive, focusing on hydration, nutrition, antiemetics, antibiotics for secondary infections, and control of seizures when needed. Prognosis varies and is poorer for animals with severe or neurologic disease.

Prevention relies on vaccination. Core vaccines for dogs include CDV, typically given in combination vaccines. Reducing exposure through isolation and sanitation is also important, and wildlife vaccination programs are used in some regions to mitigate spillover.