Naturally occurring Mycobacterium scrofulaceum infection in a laboratory mouse colony.

A contamination with Mycobacterium scrofulaceum was experienced in a colony of BALB/c-nu/nu mice. The contamination was noticed after introduction of C57BL/6 and C57BL/6. Lyt l. 1 strains into facilities that kept the colony. M. scrofulaceum seemed to be spread by oral infestation and cross-contamination of fecal excretions during handling of the mice. The organisms were shed continually or intermittently into feces of weaned nu/+ and nu/nu mice of BALB/c background, and were isolated from the mesenteric lymph nodes and spleen of some of the mice. Some of the bacillus-carrying mice developed serum antibody to M. scrofulaceum of IgG and IgA classes and gave a low degree of hypersensitivity to PPD from M. tuberculosis.     

Naturally occurring subclinical Corynebacterium kutscheri infection in laboratory rats: strain and age related antibody response

Naturally occurring subclinical Corynebacterium kutscheri infection was analyzed by antibody response related to the strain of rats. Wistar-Lewis, Wistar and Spraque-Dawley rats were high responders in seroconversion rates and antibody titers, while Brown Norway and Fischer rats were low responders. The antibody response was related to age also. Some young rats had maternal antibody to C. kutscheri, but antibody disappeared before 8 weeks of age. Rats were antibody-negative for several months thereafter and became antibody-positive after 6 months of age. The antibody response was highest at 8 to 9 months of age in subclinical C. kutscheri infection. This antibody response was very late, compared to the antibody response to Sendai virus and Mycoplasma infections.     

Naturally occurring hepatozoonosis in a coyote

Schizonts of Hepatozoon sp. were found in the myocardium of an adult cyote (Canis latrans) collected from the Aransas National Wildlife Refuge, Austwell, Texas. This constitutes the first time hepatozoonosis has been recorded in Canidae in the Western Hemisphere.     

Naturally occurring mouse hepatitis virus infection in the nude mouse.

A group of athymic nude mice developed an unusual chronic wasting disease within 1-3 months after their arrival into the laboratory. Affected nude mice had severe, acute-to-chronic, active hepatitis with multinucleated giant hepatocytes and fibrosis. Vascular and central nervous system lesions were frequently present, giant cell peritonitis, ascites, and multinucleated giant cells in the intestinal epithelial villi were less frequently observed. Mouse hepatitis virus was isolated from the livers of three mice with lesions. The virus, when inoculated into nude mice, produced lesions similar to those observed in the natural outbreak.     

Naturally occurring Sarcocystis infection in domestic cats (Felis catus)

Equine protozoal myeloencephalitis is an important neurological disease of horses in the United States. Consequently, there is an active research effort to identify hosts associated with the primary causative agent, Sarcocystis neurona. The purpose of this study was to determine whether the domestic cat (Felis catus) is a natural host for S. neurona. Muscle sections from 50 primarily free-roaming domestic cats were examined for the presence of sarcocysts. Serum from cats in this group and another group of 50 free-roaming cats were evaluated for the presence of S. neurona antibody. Sarcocysts were found in five of 50 (10%) cats, and S. neurona antibody in five of 100 (5%) cats. Morphological, molecular (including ribosomal RNA genes), and biological characterisation of these sarcocysts showed that they were not S. neurona or S. neurona-like. Sarcocysts found in the cats were identified morphologically as Sarcocystis felis, a common parasite of wild felids. The life cycle of S. felis is not known, and prior to this study, no molecular marker for S. felis existed. Although cats were found to be infected with S. felis sarcocysts, serological data provided evidence of possible infection with S. neurona as well. Further work is needed to determine the role of the domestic cat in the life cycle of S. neurona.     

Naturally occurring erysipelas in rats

Erysipelothrix rhusiopathiae was isolated from the main limb joints of two Sprague Dawley rats affected by spontaneous lesions of chronic fibrinopurulent polyarthritis, endocarditis and mycocarditis.     

Naturally occurring Bacillus piliformis infection (Tyzzer's disease) in guinea pigs

Two juvenile male Hartley guinea pigs (Cavia porcellus) were found dead 36 hours after receipt from a commercial source. Both guinea pigs had dependent, subcutaneous edema and excess serous fluid in their thoracic and abdominal cavities. Their livers were mottled and the cecal walls were reddened focally. Histopathologic exam revealed nests of Bacillus piliformis within the absorptive epithelial cells of the ileum, cecum and colon. Vegetative organisms and spore-like structures were observed in the cytoplasm of intestinal epithelial cells by electron microscopy. A diagnosis of Tyzzer's disease was made.     

Propagation of CAR bacillus in artificial media.

CAR bacillus propagated successfully in an artificial medium, and the number of CAR bacillus was about 30 times the original number after 8 days of cultivation. The medium consisted of Eagle's minimum essential medium supplemented with 10% fetal calf serum and 20% hamster tracheal organ culture soup. By intranasal inoculation to mice, two strains of the CAR bacillus passaged 5 and 6 times in this artificial medium produced the same lung lesions as natural CAR bacillus infection.     

Naturally occurring genital mycoplasmosis in mice

The first isolations of Mycoplasma pulmonis were made from inflamed ovaries of 2 C3H/F1 mice. Investigation of cultures from a further 110 apparently healthy mice revealed 14 cases of M. pulmonis localized in the ovaries and associated with oophoritis.     

Naturally occurring Bacillus thuringiensis in Indonesia

S. HASTOWO, B.W. LAY AND M. OHBA. 1992. A total of 135 strains of Bacillus thuringiensis were isolated from soils of sericultural and natural environments of various regions in Indonesia: Sumatra, Java, Bali, Timor, Sulawesi and Kalimantan. Serologically, 63 strains were assigned to flagella (H) serotypes 3abc, 3ade, 4ac, 5ac, 6ab, 8ab, 9, 11, 17, 20ac, and 24, indicating a varied flora of B. thuringiensis in Indonesia. Of these, the serotype 3ade predominated, followed by the serotypes 3abc and 6ab. The other 72 strains (53·3%) were not sero-reactive against any of the H antisera to B. thuringiensis H serotypes 1–24. In toxicity tests, 34 strains belonging to serotypes 3abc, 3ade, 4ac, and 8ab showed larvicidal activity to the silkworm, Bombyx mori, while 74·8% did not exhibit insecticidal activity against larvae of B. mori and the mosquitoes, Aedes aegypti and Culex quinquefasciatus. Morphotypes of parasporal inclusions were not correlated with insecticidal activities.     

Pathogenicities of two CAR bacillus strains in mice and rats

Two strains of CAR bacillus from a mouse (CB-M) and a rat (CB-R) which were passaged 11th in embryonated chicken eggs via the allantoic route were inoculated intranasally in ICR mice and Wistar rats. The histopathological changes and the localization of the CAR bacillus in the tracheas and lungs of these animals were investigated microscopically 2, 4 and 8 weeks postinoculation (PI). Histopathological changes similar to those in natural cases of CAR bacillus infection, showing severe peribronchial lymphoid cuffing, were first recognized 4 weeks PI. CAR bacillus was also found on the cilia of the respiratory epithelium. These histopathological changes were more remarkable in mice inoculated with CB-M and in rats inoculated with CB-R.     

Naturally occurring benzodiazepines in human milk

The presence of benzodiazepine-like molecules was detected radioimmunologically in the plasma and milk of 12 women and in the plasma of 9 men. All subjects were non-users of benzodiazepines. The concentration of these biological materials expressed as diazepam equivalents per mL amounted to 2.54 +/- 0.74 ng in male plasma; to 2.20 +/- 0.35 ng in female plasma and to 1.91 +/- 0.54 ng in milk. Further investigation of the active compounds in milk permitted the unequivocal identification of diazepam, both free and bound to a presumably protein carrier and, at least, three more benzodiazepine-like molecules. Their origin either from dietary sources or as a result of endogenous biosynthesis is still unclear.     

Hexamitiasis in a laboratory mouse colony

An acute fatal disease occurred in a mouse colony at the authors' institution. The disease caused 50% mortality among weanling mice, and was characterized clinically by depression, rough hair coat, and distention of the abdomen. The most prominent gross lesions were watery fluid and gas in the small intestine. Numerous organisms identified as Hexamita muris were seen in direct smears of the intestinal fluid. Microscopic and electron microscopic examination revealed the same organisms in the intestinal crypts, within the mucosal epithelium, and in the lamina propria. Treatment with dimetridazole controlled the clinical disease but did not eliminate the infection.