| Canine distemper (CD) is caused by canine distemper virus (CDV) which belongs to the genus Morbillivirus within the family Paramyxoviridae, it was occurrence all over the world.The natural host for CDV was canine carnivores, but it has expanded to predominantly carnivores during the past two decades. Recently many wildlife populations were infected with canine distemper virus. CDV belongs to pan-tropic virus, infects different cell types and induce interstitial pneumonia, catarrhal enteritis and non-suppurative encephalitis. Lin Zeng et al (2008) isolated CDV from Rhesus monkeys in the quarantine time. Phylogenetic analysis indicated the CDV in the Rhesus monkeys belonged to the clade of the epidemic CDV types of China. We designed three experiments to compare the clinical symptom, pathological changes and interspecific difference among three Mammals infected with CDV.First, the lung, spleen, small intestine, lymph nodes, brain, liver, and other organizations from the Rhesus monkeys were fixed in 10% neutral buffered formalin and then embedded in paraffin. Serial sections were cut and stained with hematoxylin and eosin (HE) for histopathological examination. Made tissue homogenate and inoculate ferrets and dogs for supernatant solution. We observed the changes in clinical symptoms and pathological autopsy, fixed the tissues and stained for histopathological observation. The results showed that on the 7th day and 8th day after inoculation, ferrets and dogs were both sick and made severe respiratory symptoms and gastroenteritis, several cases showed mild neurological symptoms. Necropsy visible:lung of ferrets were severe congestion and hemorrhage. Lung of dogs were purulent lesions in large area and hemorrhage in the edge. Intestinal tract was catarrhal enteritis and hemorrhage in varying degrees and spleen was minor swelling. Part of ferrets and dogs had showed mild cerebral edema lesions. Rhesus monkeys, ferrets and dogs show obvious interstitial pneumonia by pathology observing. However, lung of ferrets were serious hemorrhage and alveolar space filled with a large number of red blood cells. The lung of dogs showed a severe suppurative pneumonia, pulmonary parenchyma was replaced by connective tissue and inflammatory cells. The intestinal villi of Rhesus monkeys and dogs were injured seriously. Lymphocytes, macrophages and eosinophils were infiltrated in the intestine lamina propria. Ferrets showed catarrhal enteritis. Lesions in the spleen and lymph nodes consisted of focal or diffuse lymphoid depletion and lympholysis were spleen and lymph nodes consisted of focal or diffuse lymphoid depletion and lympholysis were observed. Canine bladder epithelial cells emerged a large number of eosinophilic inclusion bodies. Some ferrets can be seen gliosis. Other tissues. including the cerebrum and cerebellum, were apparently normal. Analyzing the experimental results. this CDV strain can cause serious damage on the respiratory system, digestive system and lymphoid organs of three different animals. Histopathology results proofed that interstitial pneumonia was the common feature of CDV infected containing primates. Ferret exhibited hemorrhagic lesions and dogs easy to form inclusion bodies.Then Immunohistochemistry (IHC) and In Situ Hybridization (ISH) were used to detect CDV virus antigen and virus nucleic acid distribution in the natural incidence of Rhesus monkeys and experimental inoculated animal. We detected tissues of Rhesus monkeys, ferrets and dogs by IHC. The results showed that positive rate are 100%,100%.100%of lung; 100%,100%,100% of small intestine:100%.100%,100% of spleen:100%,100%,9/10 of lymph nodes; 0%,1/6,1/2 of bladder; 0,5/6,1/5 of brain:0,1/3,1/10 of kidney; 0.1/3.0 of liver. The results of ISH detected showed: 100%,100%,100% of lung; 100%,5/6.100% of small intestine:1/3,1/3,2/5 of spleen; 0,1/3, 3/10 of lymph nodes:0,1/3,0 of brain. The results showed that the lung, spleen and lymph nodes in all animals almost positive.In this study, the variability of CDV distribution in different species was not obvious, the respiratory system, digestive tract and lymphoid organ were damaged seriously. However, the disoperation of central nervous system in ferrets was much more serious than Rhesus monkeys. Anyway, it suggested that nonhuman primates infecting with CDV was not occasional, and it was very important and necessary to research the evolutionary basis of host switching of CDV and forecast new animal populations which could infected with CDV.
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