Isolation of lymphocytic choriomeningitis virus from wild house mice (Mus musculus) in Osaka Port, Japan.

Lymphocytic choriomeningitis virus (LCMV) was isolated from 14 out of 35 wild house mouse samples captured on two piers of Osaka port in Japan. Four of them were isolated from were isolated from 18 antibody positive mice while 10 were from 17 antibody negative mice. This is the first report of the isolation of LCMV from wild mice in Japan.     

Lymphoma associated with an epizootic of lymphocytic choriomeningitis in Syrian hamsters (Mesocricetus auratus).

A hamster-associated epizootic of lymphocytic choriomeningitis (LCM) virus infection in medical center personnel at the University of Rochester in 1973 necessitated prompt termination of the Syrain hamster colony. Necropsies were performed on 130 hamsters, blood speciments were obtained from 60 for serotest, and viral isolation procedures were done on 47. Active virus infection, as shown by virus isolation, was associated with the presence of lymphoreticular infiltrate in liver and kidney. Intraabdominal lymphoma was seen only in groups of hamsters from which LCM virus was isolated, but LCM virus was not isolated from many of the hamsters with lymphoma. Although frequency of intraabdominal lymphoma could be markedly increased in LCM-positive hamsters treated with 7,12-dimethylbenz(a)anthracene, lymphoma was not induced in LCM-negative hamsters with this carcinogen.     

Seroepidemiological survey of lymphocytic choriomeningitis virus in wild house mouse (Mus musculus) in Yokohama Port, Japan.

From 1985 to 1989, a total of 129 mice was captured from 7 piers of Yokohama port. Of these, 9 (7.0%) were positive to lymphocytic choriomeningitis virus (LCMV) antigen in indirect fluorescence antibody test. Six out of 31 mice (19.4%) in 1985 and 3 out of 23 mice (13.0%) captured in 1986 were positive. All the mice (74) captured in 1988 and 1989 were negative. Although 7 out of 17 mice (41.2%) in Osanbashi-Shinko pier and 2 out of 23 (8.7%) in Honmoku pier were positive in 1985 and 1986, all mice captured in other piers were negative. This is the first report detecting LCMV antibody in wild house mice in Japan.     

Two epizootics of lymphocytic choriomeningitis virus occurring in laboratory mice despite intensive monitoring programs.

Two epizootics of lymphocytic choriomeningitis virus in mice occurred within two months in one research facility consisting of several widely separated rooms. These outbreaks developed despite intensive institutional monitoring policies designed to prevent introduction and spread of lymphocytic choriomeningitis virus. Evidence derived from serological and virological assays and interviews with the concerned investigators suggested that a single transplantable tumor carried in mice may have been responsible for spread of the virus. However, the tumor was not contaminated with lymphocytic choriomeningitis virus at the time of its introduction into the mouse facility. The origin of the virus responsible for the outbreaks was not definitively established although data supported an hypothesis that the virus was introduced into the research facility by a wild or feral mouse. Virus spread from infected mice to humans did not occur, as measured by serological tests. However, a large and valuable animal facility was depopulated for safety reasons. Absorption of sera with lymphocytic choriomeningitis virus antigen proved a necessary and reliable method for confirming specificity of lymphocytic choriomeningitis virus fluorescence-positive reactions.     

The potential role of Syrian hamsters and other small animals as reservoirs of lymphocytic choriomeningitis virus

The history of human infections with lymphocytic choriomeningitis virus is briefly reviewed, with special reference to those of recent years associated with pet Syrian hamsters. Many human infections have been too trivial to have come to the attention of a physician but others have required long periods of convalescence. There is also evidence that foetal damage has arisen from infection during pregnancy.
The virus is perpetuated by vertical transmission in those colonies of wild house mice which are tolerantly infected. These mice excrete the virus throughout life at a high titre in urine and saliva. Experimental evidence is presented which demonstrates the transfer of infection from such mice to Syrian hamsters when natural conditions are simulated. Hamsters infected before weaning may appear healthy while excreting the virus at a high titre for several months, during which they are a serious health hazard to their owners. This secondary reservoir of the virus brings the source of infection one step nearer to the veterinarian in practice, and to his clients, and he will be in a key position to inform or assist his medical colleagues if this hazard is suspected.     

Direct immunofluorescence testing of normal feline nasal planum and footpad

Direct immunofluorescence testing for IgG, IgM, and C3 was performed on nasal planum and footpad tissue from 28 normal cats. Granular deposition of IgM at the basement membrane zone of the nasal planum was demonstrated in 3 of 28 cats. Direct immunofluorescence testing of the footpad was negative in all cats. It was concluded that positive direct immunofluorescence testing of the feline nasal planum using antifeline IgM needs to be cautiously interpreted, as 11% of normal cats may be positive.     

Rapid diagnosis of Aujeszky's disease in pigs by immunofluorescence

Direct immunofluorescence on impression smears of brain and pharynx was compared with virus isolation in cell culture for the diagnosis of Aujeszky's disease in experimentally and naturally infected pigs. Pharyngeal impression smears were more sensitive than virus isolation in two pigs killed 10 and 12 days after experimental infection. Both methods were of similar sensitivity in the detection of virus from field cases of disease. Smears of brain and pharynx were more sensitive than virus isolation for tissue which had been stored at room temperature (approximately 20 degrees C) for up to 48 hours. Some reduction in the amounts of virus recovered from tissues and the intensity of fluorescent staining occurred in these samples.     

Direct immunofluorescence tests with counterstains for detection of Chlamydia psittaci in infected avian tissues.

Different methods of preparation and serological evaluation of rabbit globulins for use in fluorescent antibody conjugate and different methods of counterstaining with fluorescent antibody tests were evaluated for detection of Chlamydia psittaci in infected turkey tissues. The agar gel precipitin reaction was that chosen for testing and selecting antiserums to be used for fluorescein isothiocyanate conjugation. The fluorescent antibody staining was most pronounced with conjugate made from globulins precipitated with ammonium sulfate. A direct fluorescent antibody method with Evans blue counterstain correctly identified "coded" specimens of C. psittaci-infected and noninfected turkey air sacs. However, naphthalene black was superior to Evans blue as a counterstain when infected pericardial sacs were tested.     

Use of immunofluorescence technic for the diagnosis of rotavirus infection in the calf

A methodical account is given of possible applications of the immuno-fluorescence technique in the diagnosis of rotavirus infection of calf. The technique has proved suitable for routine checks for both its low input in terms of method and hardware and its potential of diagnostic information. The two latter methods are best applicable under routine conditions to testing of faeces-inoculated cell cultures as well as to the detection of rotavirus from faecal smears and frozen intestinal sections. In investigations on the dynamics of rotavirus development in cell cultures, the first freshly formed virus protein was detected six hours from inoculation. The time of one replication cycle was found to be between 16 and 18 hours, with several replication cycles running consecutively, when it comes to virus strains which have become adapted to the cell cultures concerned.