The Investigation Of Incidence Regularity And Pathological Change On Canine Parvovirus Disease In Baoding

Form five directions of Baoding(north, south, east, west and middle),we chose five representative animal hospitals of 27351 cases for survey, and summed up the incidence regularity of canine parvovirus disease in Baoding. The result indicated that there is seasonal difference in the incidence of CPVD, the incidence ratio is the maximum in winter, fewer in spring or autumn, and the minimum in summer. Purebred dog has high incidence and native breed dog has low.There is no significant difference in gender, even males are 2.24% higher than the females. CPVD has the highest incidence at 1-6 months of age, especially at 2-4 months;Vaccine plays an important role to reduce the incidence of CPVD, the un-vaccinated dog has the highest morbidity, the first immune dog also has 27.31% incidence, with the increase of age and the increasing number of immune, CPVD incidence gradually reduce. And domestic and foreign vaccines all have good protection for CPVD, both two have no significant difference in decreasing CPVD incidence.Preliminary experiments used homemade CPV feces venom to attack poison, determined the best method was injecting 1.5 ml CPV feces venom subcutaneously. According to the pre-experiment, successfully made out 8 CPVD models with one hundred percent. Among them, 3 cases of experimental dogs showed ck and LDH were beyond the linear range and tested positive for CPV, and existed myocardial inflammation detected by ecg waveform, which were judged to be CPVD myocarditis type. Five cases of experimental dogs reflected ck and LDH were within the linear range, tested positive for CPV, and appeared the typical symptom of enteritis CPVD, which judged to be enteritis CPVD.According to the symptoms, the development process of CPVD disease was divided into three periods: CPVD 1 stage(preliminary stage), CPVD 2 stage(interim) and CPVD 3 stage(anaphasis). According to the stages, blood routine examination, electrolyte and electrocardiogram were detected, then dissected the dog and observed its pathological changes, and heart,liver, spleen, small intestine were taken to produce the pathological sections, stain with HE and observe by microscope. Routine blood determination results: At the CPVD preliminary stage, WBC,Lymph#,Mid#,Lymph% and Mid% were all normal, Gran# and Gran% elevated moderately, MCV and MCHC increased significantly. At the CPVD 2 stage,WBC,RBC,HCT,HGB,Lymph# and Lymph% were all reduced, the change of mid# and mid % was uncertain while it would rise when allergy and parasites secondary infections occurred. CPVD anaphasis can divide into two cases: one was good situation,Gran#and Gran% arose,WBC increased gradually, Lymph#,Lymph% and monocytes arose; the other one was worsen situation, WBC, Lymph#, Lymph%, Gran#, Gran%, RBC and HCT all reduced, PLT significantly reduced. Electrolyte determination results: one of the 8 experimental canine was low permeability dehydration,the rest were isotonic dehydration; The flux of potassium and chloride ions in serum presented declined trend. The change of serum calcium ions was similar to a V-shape. At CPVD 2 stage, serum calcium ions reduced under linear range, and at CPVD 3 stage, the concentration serum calcium ions had a slight rebound while still under the normal linear limitation. Serum phosphate ion changed irregularly, but the data still within the reasonable linear range. After the infusion, the comparison results of electrolytes supplement and loss showed: when permeability dehydration CPVD cases that weight loss was less than 10% were supplied additional potassium, physiological saline, ringer’s lactate solution and ringer’s solution all can satisfy the demand of organism for sodium, chloride and potassium. If without additional potassium supplement, it’s not suggested to use ringer’s solution with recommended infusion quantity independently. Electrocardiogram(ecg) determination results showed:Two myocarditis experimental dogs had hypokalemia electrocardiogram(ecg), Characterized by S- T period shorten, T wave voltage reduced, at the same time U wave appeared.One myocarditis type test dog did not appear hypokalemia ecg. Three myocarditis type test dogs appeared P wave extended more than 0.05 s and broadened, QRS prolonged more than 0.06 s. P wave of No. 4 and No. 8 test dog appeared intermittent incisures. The pathological histology observation results: Intestinal mucosal epithelial cell presented degeneration, necrosis and falling off, and the intestinal villus atrophy and shorten. The top of the epithelial cell became vacuoles. The top of the lamina propria vascular appeared congestion. Lee’s fossae was less in the base of intestinal villus. Mesenteric lymphcytes appeared hyperemia swelling. The medullary sinus was full of erythrocytes. Lymphoid follicles appeared hyperplasia. Mucosal epithelial cell large intestine emerged degeneration, necrosis and shedding light. Myocardium arose granular degeneration and vesicular degeneration and myocardial fibers bacame swelling, thin dyeing. It appeared many subtle grains between myofibril and some nuclear occurred vacuoles around, some nuclear elongated, and myocardial fibers infitrated with inflammatory cells. It emerged congestionen,largement and fatty degeneration of the liver and blood clot of spleen, splenic cord narrowing, the rod endothelial gap of splenic sinus in parallel arrangement widened, sinus with inflammatory cells infiltration and Lung lymph follicles hyperplasia with a germinal center, pulmonary interstitial broadening, Lung bronchioles in lymphocytes with plasma and inflammatory cells infiltration, the accumulation of a large number of erythrocytes in the pulmonary alveoli of congestion area, alveolar walls narrowing down in emphysema area, and alveolar space significantly increasing.