Prevalence and spread of enterohepatic Helicobacter species in mice reared in a specific-pathogen-free animal facility.

Infections with enterohepatic Helicobacter species (EHS) can change the results of animal experiments. However, there is little information about the prevalence of EHS in noncommercial animal facilities. The aim of this study was to investigate the prevalence and the spread of EHS in specific-pathogen-free (SPF) mice. Fecal samples of 40 mouse lines were analyzed for members of the family Helicobacteraceae using a group-specific PCR targeting the 16S rRNA gene. Additional experiments were carried out to evaluate the spread of EHS among mice harbored in different caging systems. Helicobacter species were detected in 87.5% of the mouse lines tested. Five different Helicobacter species were identified: H. ganmani, H. hepaticus, H. typhlonicus, and the putative Helicobacter species represented by the isolates hamster B and MIT 98-5357. Helicobacter infection did not spread between animals in neighboring cages when individually ventilated cages were used; in contrast, when the mice were reared in open-air cages, EHS were found to spread from cage to cage. However, the spread was prevented by adding polycarbonate filter tops to the cages. When Helicobacter-negative and infected mice shared the same cage, transmission of the infection occurred in 100% within 2 weeks. Furthermore, we found that mice from commercial breeding facilities may carry undetected Helicobacter infections. Taken together, we show that infection with EHS may frequently occur and spread easily in mice reared under SPF conditions despite extensive safety precautions. Moreover, there is a high prevalence of rather uncommon Helicobacter species that may be a consequence of the current routine procedures used for health screening of SPF mice.

Persistent hepatitis and enterocolitis in germfree mice infected with Helicobacter hepaticus.

Helicobacter hepaticus has been associated with naturally occurring hepatitis in certain inbred strains of mice, and in A/JCr mice it has been linked to the development of hepatic adenomas and adenocarcinomas. H. hepaticus was orally inoculated into 30 axenic, outbred female mice, and the mice were studied longitudinally to fulfill Koch's postulates and to ascertain the pathogenic potential of the organism under defined germfree conditions. Ten cage contact mice were also housed in the same germfree isolator to study transmission patterns, and 10 germfree mice were maintained in separate isolators as controls. Mice serially euthanized from 3 weeks through 24 months postinoculation (p.i.) were surveyed by culture and PCR for H. hepaticus in liver and intestinal tissues. Tissues were analyzed for histopathological changes, and sera were assayed for the presence of immunoglobulin G antibody to H. hepaticus and changes in the liver enzyme alanine aminotransferase. Inoculated mice and cage contact mice were persistently infected with H. hepaticus as identified by culture and PCR, in both the intestine and, less frequently, the liver, for the duration of the 2-year study. Animals developed persistent chronic hepatitis, and in some animals enterocolitis was noted. Hepatocellular carcinoma was diagnosed in one H. hepaticus-infected mouse. The level of H. hepaticus serum antibody was highest in experimentally infected mice at 12 to 18 months p.i.; this corresponded in general to the time interval when the highest levels of alanine aminotransferase were recorded. Although cage contact mice became persistently infected with H. hepaticus, lesions were less severe and the levels of serological biomarkers utilized in the study were lower. The H. hepaticus-infected mouse will provide an ideal model to study putative bacterial virulence determinants and how they interact with the host to induce chronic inflammation and tumorigenesis.

Evidence for the presence of duck hepatitis B virus in wild migrating ducks.

A virus closely related to duck hepatitis B virus (DHBV) was isolated from serum and liver samples of wild migratory ducks (mallards) caught in two separate wildlife reserve parks in France. In the first one (Dombes region) 12% of wild mallards were positive for DHBV, and in the second (River Somme) 3% of mallards were found positive. The DHBV isolated from the serum of wild mallards was also associated with an endogenous DNA polymerase activity capable in vitro of completing a partially double-stranded viral DNA into a fully double-stranded DNA of 3 kb. The various replicative DNA forms reported for DHBV were also detected in the liver of wild viraemic mallards. The DNA restriction enzyme pattern of the wild mallard strain differed from that of American and French strains of DHBV. The wild mallard strain DHBV was experimentally transmitted to mallard and Pekin ducklings and induced a chronic viraemia in both varieties of infected birds. This strain might be the common ancestor of all DHBV strains isolated from domestic ducks world-wide. The discovery of a DHBV-related virus in the natural wild population might be an important clue in the study of the different roles of environmental, host and viral factors in the pathogenesis of DHBV infection, and their possible oncogenic action in ducks.

A new transmissible agent causing acute hepatitis, chronic hepatitis and cirrhosis in dogs.

There is a hepatitis of dogs which occurs in acute, persistent and chronic forms. Histological studies of spontaneous cases suggested that several apparently diverse hepatic diseases might be stages of one process. This was also implied by follow up studies and case histories: acute non-lethal episodes were followed later by the development of chronic hepatitis, cirrhosis and liver failure. Serum was taken and homogenates of liver were made from three field cases representing different putative temporal stages of the complex. These were injected into experimental dogs and a hepatitis was induced in all. The cytopathological and histological changes were the same in all animals and were identical to field cases. Acute lethal disease and persistent infections were produced. Two second passages were carried out and an identical condition was induced, characterised by recurrent episodes of subclinical hepatitis and persistent infection. It is suggested that the disease might be named canine acidophil cell hepatitis in view of the pathognomonic cytopathology. Specific morphological criteria have been established for this hepatitis.

Infectious necrotic hepatitis caused by an unclassified anaerobic bacillus in the water snake.

Necrotic hepatitis resembling black disease of ruminants is described in a group of five water snakes (Natrix sipedon pictiventirs). Lesions varied from multifocal granulomas to massive coagulation necrosis. A bacterium recovered from the livers could not be classified, but closely resembled Eubacterium tarantellus. The bacterium was isolated from all snake livers and from snake mites (Ophionyssus natricis) which were probably implicated in the transmission of the disease and it is possible that trematodes were concerned in producing the initial damage to the liver.

Carrier state of antibody and viruses in a mouse breeding colony persistently infected with Sendai and mouse hepatitis viruses.

In a large-scale mouse breeder colony persistently infected with Sendai and mouse hepatitis viruses, most adult breeders 8 wk or more of age were shown to have antibodies to both viruses when monitored over a periof of 20 mo. Antibody to Sendai virus, apparently transmitted from the dam, was detected in 76% and 2% of mice aged 3 and 4 wk. respectively, and 64% and 100% of mice aged 6 and 8 wk, respectively. By seroconversion of sentinel cage-mates, a Sendai virus-carrier state was demonstrated with 6-wk-old mice but not with those either 4 wk or 10 wk of age, suggesting that breeder candidates about 6 wk of age may play an important role in establishing and perpetuating Sendai infection in this breeding colony. With mouse hepatitis virus, however, mice aged 4 wk or older seem to be effective transmitters of the virus, while some of these mice were found to have antibody to the virus.

Induction of chronic lethal Australia antigen hepatitis in mice.

Clinically, idiopathic uveitis may be associated with chronic active hepatitis B. In searching for a possible cause of the uveitis in 6 patients having concurrent chronic iridocyclitis and chronic active hepatitis with serum Australia antigen (AA), the aqueous humor from each patient was analyzed for AA, passed through 220-mmu filters and inoculated directly into the livers of mice. The animals were observed for spontaneous mortality for 12 months, at which time the remaining animals were sacrificed. The livers of all animals were examined for hepatitis and AA. Although the aqueous humor from only 1 patient was found to contain AA, all six aqueous specimens produced a lethal viral hepatitis-like disease with liver AA. The results suggest that the six positive aqueous specimens contained a viral infection agent, which may have been the core of the Dane particle, and that the mouse is suitable for the laboratory investigation of Type B hepatitis by the technique described.

Lesions in chickens with spontaneous or experimental infectious hepato-myelopoietic disease (inclusion body hepatitis) in Germany.

A group of 83 two-to-eighteen-week-old chickens with acute infectious hepato-myelopoietic disease (a German form of inclusion-body-hepatitis) were observed to have the following histologic lesions: panmyelophthisis, small foci of liver necrosis, often with intranuclear inclusion bodies in hepatocytes (15 to 20% of chickens), involution-like atrophy of the bursa of Fabricius and thymus, loss of lymphatic tissue in spleen and cecal tonsils, and nonpurulent myocarditis. In 18 survivors 6 to 8 weeks after clinical signs of disease, nonpurulent myocarditis but normal lymphatic organs and bone marrow were present. A group of 75 chickens were infected after hatching with the field isolant "1942." Between the 3rd and 9th weeks postinoculation the same histologic changes-though mostly milder-were demonstrated. This syndrome differs somewhat from the syndrome described as inclusion body hepatitis in America and Europe.

Incidental aquatic zoonoses.

The following incidental aquatic zoonoses are discussed: eosinophilic mengingitis caused by Angiostrongylus cantonesis, the Guinea worm (Dracunculus medinesis), Anisakis infections, Cryptocotyle lingua, eye fluke (Philophthalmus), the tapeworm Diplogonoporus grandis, and shellfish-borne hepatitis.