Neurological Manifestation of Canine Distemper Virus: Increased Risk in Young Shih-Tzu and Lhasa Apso with Seasonal Prevalence in Autumn

Canine distemper virus (CDV) is a critical disease in veterinary neurology, marked by high morbidity, mortality, and frequent neurological sequelae. This study aimed to identify epidemiological patterns and risk factors associated with neurological manifestations of CDV infection. CDV-naturally infected dogs with neurological signs were retrospectively analyzed and compared to a control group of dogs with other CNS diseases. Infection was confirmed using antigen tests, RT-PCR, and/or Lentz corpuscle observation. Clinical signs, seasonality, and vaccination protocols were documented. Prevalence, mortality, lethality, and survival rates were also determined. Younger dogs (p=0.0069; OR=-0.01438), Shih-Tzu (p=0.00007; OR=1.53774), and Lhasa Apso (p=0.000264; OR=1.76084) were more likely to develop neurological CDV signs. Most CDV-infected dogs exhibited multifocal CNS involvement (10/17) and accompanying extra-neural signs (16/17). Motor deficits represented the most frequent neurological manifestation (13/17), while myoclonus was observed in only one-third (6/17) of the cases. Cases were more frequent in autumn (8/17), and many dogs had updated vaccination protocols (6/17). The prevalence, mortality and lethality of dogs with CDV were estimated at 4.72%, 1.94% and 47.06%, respectively. The median survival time was 754 days. Young adult dogs, particularly Shih-Tzu and Lhasa Apso, are more susceptible to neurological CDV manifestations, with the highest incidence in autumn.