Psittacid herpesvirus 1 causes Pacheco's disease in psittacine birds. Pacheco's disease rapidly kills birds by causing fatal hepatitis, but often shows no clinical symptoms before death (Katoh et al., 2010). Pacheco’s disease (PD) is a highly contagious, acute disease of psittacines caused by a herpesvirus. It is associated with stress, which can cause clinically healthy carriers to shed virus and initiate infection in susceptible birds. It is spread by direct contact and by aerosol or fecal contamination of food or water. Macaws, Amazon parrots, Monk parakeets, and conures are often involved in outbreaks. Old World species are less likely to be either inapparent carriers or clinically susceptible. Patagonian species and some Aratinga sp may be natural hosts in the wild, and some individuals of these species may asymptomatically shed virus when stressed. Other species can also act as carriers. Terminal signs include acute death in well-fleshed birds and bright yellow urates with scant feces. Due to the acute nature of the disease, no gross histologic lesions may be evident. Most affected birds, however, will have an enlarged liver, splenomegaly, and renomegaly. The liver may be mottled or grossly discolored. Ecchymotic and petechial hemorrhages may be present on the pericardium and within the mesenteric fat (Merck Vet Manual: Pacheco's Disease).
1. Katoh et al., 2010: Katoh H, Ogawa H, Ohya K, Fukushi H. A review of DNA viral infections in psittacine birds. The Journal of veterinary medical science / the Japanese Society of Veterinary Science. 2010; 72(9); 1099-1106. [PubMed: 20424393].
