Canine parvovirus myocarditis: clinical signs and pathological lesions encountered in natural cases

Canine parvovirus (CPV) myocarditis was diagnosed in 11 puppies during 1979. The diagnosis was made at histopathological examination on the basis of 2 characteristic lesions: a subacute to chronic fibrous myocarditis and the presence of large, basophilic intranuclear inclusions in the cardiac myofibres. The puppies varied from 31/2 to 8 weeks of age and all died suddenly without prior symptoms except for 1 pup which developed a severe respiratory dyspnoea 12 h before death. The presence of white bands or streaks of fibrosis on the endocardial or epicardial surfaces of the ventricles was a characteristic gross finding in 65% of cases. In all cases the lungs revealed a pneumonitis noted as hypercellularity and thickening of the alveolar walls. Alveolar macrophages were present within the alveolar lumens. The latter lesion was regarded to be secondary to heart failure. The clinical symptoms and pathological lesions observed are discussed and compared to these noted by various other workers both in South African and in other countries.

Concomitant occurrence of Campylobacter and parvoviruses in dogs with gastroenteritis

In 1979 a canine parvovirus infection was widespread among dogs in Sweden. During the epizootic faecal samples were taken for bacteriological examination from 77 hospitalised dogs at an animal clinic. Forty-nine of the dogs had signs of gastroenteritis and they were all infected with canine parvovirus according to serological investigations. The remaining 28 dogs were referred to the clinic for other reasons. Campylobacter was isolated from 23 out of the 49 dogs with gastroenteritis and from 4 out of 28 dogs lacking symptoms of enteritis. The significance of these findings is discussed.

[Canine parvovirus infection in a group of beagles (author's transl)]

An outbreak of canine parvovirus infection in a group of 26 beagles was described. The disease characterized by acute intestinal involvement was highly contagious but fatality was low (1/26). Transient leukopenia was recorded in some animals. All the convalescent sera were positive in agar gel diffusion test using feline panleukopenia virus antigen. Histopathological examination on fetal dog revealed regressive change associated with formation of amphophilic intranuclear inclusion bodies in the enterocytes of the Lieberkühn's crypt and regressive change in the lymphoid tissues. Pathologic picture exhibited strikingly resemblance with that of feline panleukopenia.

Canine parvovirus in a commercial kennel: epidemiologic and pathologic findings

A study was conducted at a large canine commercial kennel that had suffered serious losses due to epidemic diarrheal disease following the introduction of canine parvovirus (CPV) into the kennel population. Mortality was highest in weaned (9- to 12-week-old) puppies coincident with the decline in maternal antibody titers. Virus was present in fecal samples from both fatal and non-fatal cases. Intestinal lesions of varying severity were present in dogs that died. One case of myocarditis occurred in a 5-week-old puppy. Reproductive performance was unaffected by the introduction of canine parvovirus into the kennel population.

Vaccination against porcine parvovirus infection

Of 13 gilts 7 were vaccinated twice at an interval of 3 weeks with an inactivated vaccine against porcine parvovirus (PPV) infection, while the 6 nonvaccinated gilts served as controls. Starting after the 1st vaccination the gilts were bred and, after about 40 days of gestation, challenged intravenously with virulent PPV. The vaccinated gilts produced an antibody respons after the 1st and 2nd vaccination compatible with a primary and a secondary immune response, respectively. The nonvaccinated gilts remained low-titered or PPV antibody negative until after challenge. The gilts were killed after about 90 days of gestation, and their litters were examined. All of 53 fetuses from the vaccinated gilts were alive, and infection with PPV could not be demonstrated. Conversely, 50 of 65 fetuses from the non-vaccinated gilts were infected with PPV, and 43 were dead.

In a field study comprising 2 herds, PPV seronegative or lowtitered gilts were vaccinated before mating. There were no obvious signs of reproductive disorders in the 2 herds during the vaccination trials, and the reproductive performance of vaccinated gilts did not differ significantly from that of non-vaccinated gilts.

Nosocomial viral infections: III. Guidelines for prevention and control of exanthematous viruses, gastroenteritis viruses, picornaviruses, and uncommonly seen viruses

This communication is the third in a four-part series on nosocomial viral infections from the Strong Memorial Hospital. This third article discusses guidelines for prevention and control of exanthematous viruses, gastroenteritis, viruses, adenoviruses and the picornaviruses other than rhinoviruses. Several uncommonly seen viruses, such as the virus of Creutzfeldt-Jakob disease and Marburg, Ebola, and Lassa fever viruses, also are reviewed briefly.

Norwalk virus gastroenteritis aboard a cruise ship: an outbreak on five consecutive cruises

An explosive outbreak of gastroenteritis caused by a parvovirus-like (PVL) agent (Norwalk agent) affected 521 (64%) cruise ship passengers in 1977. The illness was characterized as mild-to-moderate and lasted one to two days. Principal symptoms experienced by ill passengers were nausea, vomiting, and diarrhea; fever was reported for approximately 25% of the patients. The outbreak was compatible with a common-source exposure, but no such exposure was identified. On the next four cruises, passengers experienced a similar gastrointestinal illness, but the outbreaks were less explosive, affected fewer persons, and symptoms appeared milder, on each subsequent cruise. No common source was identified, and person-to-person transmission may have occurred. The etiology of these outbreaks would have remained unknown were it not for the recent development of a specific radioimmunoassay (RIA) for the serologic identification of Norwalk virus and the measurement of antibody titers to the virus. A fourfold or greater rise in serum antibody titers to Norwalk antigen in serum from seven of eight ill passengers and the identification of Norwalk antigen in stool specimens from two ill passengers on the first cruise demonstrated that Norwalk virus caused this outbreak. The symptoms experienced by passengers on the four subsequent cruises suggest that a Norwalk agent probably also caused these outbreaks. In addition, a stool specimen from an ill passenger on cruise 3 contained Norwalk antigen.

Lesions resulting from inoculation of porcine foetuses with porcine parvovirus

In utero inoculation of 15 sows at various stages of gestation with a local strain of porcine parvovirus (PPV) resulted in resorption, abortion or the birth of weak, dead, or mummified foetuses. Histopathological lesions observed in foetuses of sows slaughtered at various post-inoculation intervals consisted of a perivascular inflammatory reaction primarily observed in the brain and kidneys. The presence and extent of the inflammatory reaction were dependent upon the age of the foetus at the time of infection. In the sow a perivascular inflammatory reaction was found in the endometrium, while the larger blood-vessel walls were infiltrated by lymphocytes, and it is suggested that these vascular lesions may contribute to the reproductive failures associated with PPV.

Myocarditis induced by parvoviral infection in weanling pups in the United States

In a nationwide survey from January 1978 through September 1979, acute parvovirus-induced myocarditis was identified in 76 of 147 (52%) pups in 19 litters. The affected pups were from 12 states. Birth of all pups registered with the American Kennel Club during this period increased during the spring months, peaking in May, which was correlated in 4 to 8 weeks with the greatest number of cases in the study. Serologic data available for 4 dams, for 6 of their surviving pups, and for 3 contact pups indicated that all had been exposed to parvovirus. In 2 kennels, cases of acute myocarditis were preceded within 2 months by cases of severe gastroenteritis in older litters on the same premises.