Studies were performed to evaluate the potential use of the bovine RIT 4237 rotavirus strain as a vaccine candidate against infection with human rotaviruses. Initial experiments revealed that colostrum-deprived piglets were susceptible to infection with several human strains, except for those belonging to subgroup 1. Subsequently, different immunization procedures with RIT 4237 were studied in this animal model. It was found that a two-dose administration, either given intramuscularly (twice) or once intramuscularly and once intragastrically, was necessary to induce a significant serum antibody response. Finally, the protective effect of the latter vaccination schedules against subgroup 2 and 3 rotavirus strains of human origin was evaluated by artificial challenge. In both cases, prior administration of live RIT 4237 significantly decreased fecal shedding of the challenge virus when compared with control animals.

The relative prevalence of human rotavirus subgroups was studied during a 3-year period (1978-1981) by means of a sensitive complement fixation technique. Among 93 rotavirus isolates from children with acute gastroenteritis in Brussels, the prevalence of subgroups 1, 2, and 3 was, respectively 24, 17, and 32%. The remaining 27% of strains could not be typed, but no evidence for the existence of any new subgroup was found. The proportion of strains belonging to the different subgroups remained roughly constant during the study period, showing the simultaneous occurrence of the various subgroups of viruses, even during the annual winter peak of rotavirus gastroenteritis.

During a 3-year period, "Campylobacter upsaliensis" was isolated from 99 patients. Phenotypic characterization and numerical analysis of protein electrophoregrams showed evidence that "C. upsaliensis" is a distinct Campylobacter species with unique characteristics. The MBCs of 13 antibiotics were determined. In general, these organisms were highly susceptible to drugs that were present in the selective isolation media, making none of the available selective media suitable for the isolation of "C. upsaliensis." Ten strains were found to be resistant to erythromycin (MBCs, .12.50 mg/liter). Plasmid DNA was detectable in 89 of the 99 strains; 16 plasmid profiles could be identified. Plasmid pattern 16, containing four plasmids of 52, 32, 5.5, and 2.6 megadaltons, represented 60.7% of the plasmid-containing strains. None of the "C. upsaliensis" strains could be agglutinated with antisera against heat-labile antigens from C. jejuni, C. coli, or C. laridis. "C. upsaliensis" was found to be susceptible to serum killing and was readily phagocytized by human polymorphonuclear cells. Catalase-negative or weakly positive (CNW) strains of Campylobacter were first isolated from dogs by Sandstedt et al. (31). In the same report, those investigators were able to demonstrate, by DNA hybridization, that these organisms belonged to a new species; the name "Campylobacter upsaliensis" was proposed in 1986 (K. Sandstedt and J. Ursing, Abstr. XIV Int. Congr. Microbiol. P.B8-17, p. 61, 1986). The species description was minimal, although a type strain (NCTC 11541 = LMG 8850) was designated. Neither the species name nor the type strain has standing in the literature, because the species description was not published in a peer-reviewed journal. CNW strains were isolated from five children with diarrhea by Mégraud and Bonnet in France (F. Mégraud and F. Bonnet, Letter, J. Infect. 12:275-276, 1986); Steele and McDermott (32) recovered eight CNW isolates from diarrheic stools of Australian children and one CNW isolate from an adult; Patton et al. (27) showed evidence that "C. upsaliensis" is responsible for enteritis in both adults and children in the United States; Taylor et al. (36) isolated "C. upsaliensis" from seven patients, both adults and children, with diarrhea in Canada; Lastovica et al. (16) isolated these organisms from blood cultures of pediatric patients in South Africa; Walmsley and Karmali (39) isolated "C. upsaliensis" from six children. Most recently, Fox et al. (8) isolated "C. upsaliensis" from three asymptomatic cats. In this report, we characterize and describe the "C. upsaliensis" group, using strains isolated in our hospital. We use the species name in quotation marks to indicate its proposed name and refer to the "type strain" as a reference strain.

We have developed a series of monoclonal antibodies against the calf strain RIT 4237 (subgroup 1) and the human strain 82-561 (subgroup 3) of rotavirus, both grown in tissue culture, and also against the human rotavirus 81-2162 (subgroup 2), extracted from a fecal specimen. A variety of different specificities was observed among these antibodies, namely, antibodies against group and subgroup determinants, as well as neutralizing antibodies. By using monoclonal antibodies against the subgroup antigen in an enzyme-linked immunoassay system, the constant predominance of subgroup 2 viruses in humans was confirmed in 74 stools collected from children in Brussels who suffered a diarrheal illness between July 1981 and June 1983. The availability of these antibodies also made it possible to improve the sensitivity and the specificity of the test system.