Feline papillomas and papillomaviruses.

Papillomaviruses (PVs) are highly species- and site-specific pathogens of stratified squamous epithelium. Although PV infections in the various Felidae are rarely reported, we identified productive infections in six cat species. PV-induced proliferative skin or mucous membrane lesions were confirmed by immunohistochemical screening for papillomavirus-specific capsid antigens. Seven monoclonal antibodies, each of which reacts with an immunodominant antigenic determinant of the bovine papillomavirus L1 gene product, revealed that feline PV capsid epitopes were conserved to various degrees. This battery of monoclonal antibodies established differential expression patterns among cutaneous and oral PVs of snow leopards and domestic cats, suggesting that they represent distinct viruses. Clinically, the lesions in all species and anatomic sites were locally extensive and frequently multiple. Histologically, the areas of epidermal hyperplasia were flat with a similarity to benign tumors induced by cutaneotropic, carcinogenic PVs in immunosuppressed human patients. Limited restriction endonuclease analyses of viral genomic DNA confirmed the variability among three viral genomes recovered from available frozen tissue. Because most previous PV isolates have been species specific, these studies suggest that at least eight different cat papillomaviruses infect the oral cavity (tentative designations: Asian lion, Panthera leo, P1PV; snow leopard, Panthera uncia, PuPV-1; bobcat, Felis rufus, FrPV; Florida panther, Felis concolor, FcPV; clouded leopard, Neofelis nebulosa, NnPV; and domestic cat, Felis domesticus, FdPV-2) or skin (domestic cat, F. domesticus, FdPV-1; and snow leopard, P. uncia, PuPV-2).

Feline hemobartonellosis.

H. felis is a rickettsial parasite that causes hemolysis and sequestration of feline erythrocytes. It should be considered as a potential primary pathogen or opportunist in any cat presented with signs ranging from episodic malaise to acute anemic collapse. Diagnosis requires visualization of the organism in properly prepared blood smears. Treatment uses antirickettsial drugs, corticosteroids, and supportive measures. Clinical recovery requires immune containment of the organism. Treatment does not eliminate the organism from the host. Carrier cats may relapse when their immunity is severely compromised by other diseases such as FeLV. Transmission is presumed to be by blood-sucking parasites and possibly bite wounds between cats. Prevention requires prudent health management of cats. Future advances in the knowledge of the disease will relate mainly to the development of a diagnostic technique that will allow identification of all infected cats.

Eastern equine encephalitis in a flock of emus (Dromaius novaehollandiae).

Eastern equine encephalitis (EEE) was diagnosed in a flock of emus in southeastern Louisiana. The outbreak involved juvenile and adult breeders ranging in age from 20 to 36 months, with an attack rate of 76% and a case fatality rate of 87%. The diagnosis was confirmed by isolation and characterization of the viral agent, and by detection of EEE antibody in two recovered emus. High mortality was preceded by marked depression, hemorrhagic diarrhea, and emesis of blood-stained ingesta. On postmortem examination, hemorrhagic enteritis and multiple petechia of viscera were observed. Microscopic changes included severe necrosis of hepatocytes, intestinal mucosa, and necrotizing vasculitis of the spleen and lamina propria of the intestine. No nervous system lesions were observed. This outbreak occurred concurrently with EEE in horses and was attributed to unseasonably heavy rainfall with an abundance of arthropod vectors and proximity to free-living reservoir host species.

Papillomavirus infection of aged Persian cats.

Papillomavirus infection was confirmed in 2 Persian cats with sessile hyperkeratotic skin lesions. Skin lesions were not typical papillomas as found in other species. Papillomavirus were demonstrated in negative stain preparations of homogenized tissue and within nuclei of cells in the stratum granulosum. Papillomavirus group-specific antigens were detected within nuclei corresponding to those containing virions. Attempts to transmit this disease to other cats or propagate the virus in tissue cultures were unsuccessful. A 7.8-kilobase DNA molecule was present in low-stringency Southern blots using a bovine papillomavirus type 1 cloned DNA probe. In reverse Southern blots, the cat papillomavirus hybridized under conditions of low stringency with all papillomavirus genomes tested. Combined with limited restriction endonuclease restriction mapping, the above information indicates that the feline cutaneous papillomavirus is a unique virus type and thus expands the list of hosts known to be infected by papillomaviruses.

Nature and classification of viruses affecting small animals.

The classification of animal viruses is predicated upon the various parameters discussed herein and the molecular biology of viruses. Although many of the parameters used for classification purposes have little obvious relation to the disease the veterinarian observes, it is necessary to utilize this information collectively to understand viral classification and its relationship to disease pathogenesis, treatment, diagnosis, and prevention because all these are predicted on the classification of animal viruses (Table 2).

Chlamydia psittaci induced pneumonia in a horse.

An agent lethal to embryonated chicken eggs was isolated from lung tissues of a quarter horse mare with a fatal respiratory disease. The lesions induced in embryonated chicken eggs, the tinctoral properties, the ultrastructural morphology, the resistance of the organism to sodium sulfadiazine, and the presence of a chlamydial complement fixing antigen, identify this isolate as a member of the family Chlamydiaceae and suggest the agent to be Chlamydia psittaci. Two Shetland ponies experimentally infected with the isolated agent developed subclinical infection as demonstrated by an increase in complement fixing antibody titers. Post mortem examination of one pony revealed microscopic evidence of a generalized chlamydial infection. Lesions of interstitial pneumonia and focal hepatic necrosis were observed, and Chlamydia psittaci subsequently was reisolated from the lung tissues of the pony.

A micro cell culture method utilizing modified microscope slides for use in fluorescent antibody and enzyme immunoassays.

A technique for culturing small quantities of mammalian cells on modified microscope slides is described. The modified microscope slides were Bellco Glass, Inc., toxoplasmosis slides and the cell cultures used were early passage bovine embryonic lung cells and continuous cell lines of porcine and canine origins. The slide cell cultures were either uninfected or infected with selected viruses or the obligate intracellular protozoanEncephalitozoon caniculi for utilization in direct and indirect fluorescent antibody testing or in peroxidase antiperoxidase immunosorbant assays.

Laryngeal diphtheria and papillomatosis in feedlot cattle.

In a random sample of 30,444 larynges from slaughtered beef cattle, 441 (1.4%) had chronic diphtheria and 1,345 (4.4%) had papillomatosis. Both types of lesions were centered in mucous membranes over the vocal processes and medial angles of the arytenoid cartilages. Since they are found in the same anatomical locations as laryngeal contact ulcers, we hypothesize that ulcers are primary and diphtheria and papillomatosis are secondary.

Electron microscopic identification and subsequent isolation of a rotavirus from a dog with fatal neonatal diarrhea.

Negative contrast electron microscopic examination of intestinal contents from a 3-day-old pup with fatal diarrhea exhibited numerous rotavirus-like particles. Rotavirus was subsequently recovered, using MDCK cells, and was carried through 11 sub-passages; rotavirus-like particles were identified in each passage by negative contrast electron microscopic examination. Experimental inoculation of two 6-month-old Beagle dogs with purified intestinal contents did not result in clinical signs or virus shedding.

Negative contrast electron microscopic techniques for diagnosis of viruses of veterinary importance.

Negative contrast electron microscopy (NCEM) was utilized as a routine tool in the diagnosis of viral infections of domestic and wild animals. Viruses identified by this technique were observed in infected culture systems or clinical specimens from several species including horses, cattle, sheep, dogs, cats, pigs, deer, Rocky Mountain bighorn sheep, antelope, and several avian species. Viruses were identified by NCEM based on their size, morphology, and symmetry and consisted of adenoviruses, herpesviruses, paramyxoviruses, myxoviruses, picornaviruses, parvoviruses, coronaviruses, reoviruses, rotaviruses, and poxviruses. Mixed populations were also readily demonstrable by this technique: the most common mixed infections consisted of coronaviruses and rotaviruses, and picorna- or parvo-viruses with coronaviruses, rotaviruses, herpesviruses, or adenoviruses. Immunoelectron microscopy was also used to serotype viral agents present in the specimens examined. Viruses identified by this technique were bovine rotaviruses, coronaviruses, and herpesviruses, and bovine and equine adenoviruses.

Isolation of a chlamydial agent from Rocky Mountain bighorn sheep.

A total of 53 clinical specimens from both healthy and diseased Rocky Mountain bighorn sheep (Ovis canadensis) were examined for Chlamydia. An agent consistently lethal for chicken embryos was recovered from a nasal swab taken from a normal ewe. This agent, designated BHS-15, possesses antigens which fix complement in the presence of anti-chlamydial serum, is susceptible to chlortetracycline, and is resistant to sodium sulfadiazine and streptomycin. Attempts to culture the isolate in quality control media, including blood agar, thioglycolate broth, and PPLO broth and agar were unsuccessful. A recommendation is made for classification of agent BHS-15 as a member of the species Chlamydia psittaci. The possible relationship of the isolate to the pneumonia complex in bighorn sheep is discussed.

Cryptosporidiosis in immunodeficient Arabian foals.

Five of six immunodeficient Arabian foals that died of adenoviral infection were found to be infected with an intestinal coccidian of the genus Cryptosporidium. Various developmental stages of the organism were found in the microvillous border of the intestinal mucosa. The foals had diarrhea but it was not possible to separate the effects of the cryptosporidial infection from those of the concomitant adenoviral enteritis.

Shipping fever pneumonia in yearling feedlot cattle.

During each week of 1974, we surveyed, for illnesses and deaths, a continually changing population of yearling feedlot cattle that, for the year, totaled 407,000 animals. About 5.1% of the cattle sickened and, of these, 18.9% died. From the 3,943 fatalities, 1,988 necropsies were made. About 75% of the clinical diagnoses and 64% of the necropsy diagnoses were respiratory tract diseases; of the fatalities from respiratory tract diseases, 75% were attributed to shipping fever pneumonia. Nearly 72% of fatal cases of shipping fever pneumonia occurred during the first 45 days on feed. In the lungs of most cattle with shipping fever pneumonia, bronchiolitis, fibrinous exudate, colonies of microorganisms, lymphatic clots, intravascular clots, thromboses, and foci of necrosis were found. Pasteurella spp, Mycoplasma spp, and infectious bovine rhinotracheitis virus were isolated from pneumonic tissues. It was hypothesized that pathogenic Pasteurella spp and other microorganisms in nasal secretions transfer from the nasopharynx into the lungs by draining along the tracheal floor into ventral bronchi, bronchioles, and alveoli, and that pasteurella endotoxin, formed in infected lobules, thromboses and occludes lymphatics, capillaries, and veins and thereby causes ischemic necrosis.

Embolic pulmonary aneurysms in yearling feedlot cattle.

Throughout all of 1974, we surveyed, for illnesses and deaths, about 407,000 yearling feedlot cattle. Of 1,988 cattle necropsied, 25 (1.3%) had ruptured pulmonary aneurysms and an additional 4 had gross pulmonary emboli without rupture. The emboli originated from thrombi in the caudal vena cava where that vessel closely applies to the left border of the liver and where parenchymal abscesses had developed. The emboli had lodged in the pulmonary artery, weakened its wall, and led to saccular aneurysms. Infection weakened and blood pressure ruptured the saccule and opened the adjacent bronchi. Extravasated blood dissected the tunica adventitia, formed hematomas, poured into the bronchus, and was expelled from the larynx. A portion was swallowed into the rumen, and some was coughed and blown from the nose and mouth. Deaths were attributed to exsanguination and pulmonary incapacitation.

Diseases of yearling feedlot cattle in Colorado.

During all of 1974 we surveyed, for illnesses and deaths, about 407,000 yearling feedlot cattle. The morbidity was 5.1%, with a case mortality of 18.9% and a population mortality of 1.0%. Both morbidity and mortality were higher during fall and winter than during spring and summer. Of the 3,943 dead cattle, 1,988 were necropsied. The most prevalent diseases were: pneumonia, 48%; diphtheria, 6%; brisket disease, 6%; hemorrhagic colitis, 5%; riding injury, 4%; bloat, 3%; calculosis, 2%; endocarditis, 2%; abomasal ulcers, 2%; bovine viral diarrhea, 2%; embolic pulmonary aneurysm, 1%; and pulmonary edema, 1%.

Atypical interstitial pneumonia in yearling feedlot cattle.

During each week of 1974, we surveyed, for illnesses and deaths, a constantly changing population of yearling feedlot cattle that, for the year, totaled 407,000 animals. From 3,943 fatalities, 1,988 necropsies were made; of this number, 106 (5.3%) had atypical interstitial pneumonia. The death rate was higher during summer and fall than during the other seasons and was evenly distributed throughout each of the 4 stages of fattening. Gross pulmonary lesions involved both lungs and were prominent throughout the caudal (diaphragmatic) lobes. Epithelialization, hemorrhage, fibrin, hyaline membranes, emphysema, bronchiolitis, and interstitial edema were common, whereas chromatin strands, bronchiolar edema, interstitial emphysema, and obliterating bronchiolitis were less common histopathologic features.

Negative contrast electron microscopic diagnosis of viruses of neonatal calf diarrhea.

Ninety-one cases of neonatal calf diarrhea were examined for viruses with negative contrast electron microscopy. Viruses were demonstrated in 41% of the cases. Reo-like viruses and corona-like viruses, and mixed virus populations were observed in 12%, 20% and 9%, respectively. Twenty-six of the cases were examined by negative contrast electron microscopy, and by virus isolation or by fluorescent antibody technique. There was an 81% agreement in obtained results. The disagreements resulted from the demonstration of a viral agent by negative contrast electron microscopy while the other techniques did not indicate a virus. The results suggest that negative contrast electron microscopy is a more sensitive diagnostic tool for demonstration of viruses associated with neonatal calf diarrhea than are viral isolation or the fluorescent antibody technique.