No abstract

SummaryThree cytopathic rotavirus strains were isolated in MA104 cells from faecal specimens of pediatric patients with acute gastroenteritis. Pre-treatment of virus with trypsin and incorporation of a small amount of trypsin in maintenance medium were important for establishment of the strains in these cells. The isolates were antigenically closely related with strain Wa of human rotavirus and had some antigenic relationship with strain Lincoln of bovine rotavirus. , Numerous attempts to propagate human rotaviruses to high titer in cultured cells have failed (1--3, 7, 8, 1t). Recently, WYATT et al. (12) adapted type 2 human rotavirus (strain Wa) to grow to relatively high titer in primary cultures of African green monkey kidney cells after 11 passages in newborn gnotobiotic piglets. In the present study we isolated 3 strains of human rotavirus in cultures of MA 104 cells, a stable cell line derived from embryonic rhesus monkey kidney.Faecal specimens were obtained from pediatric patients who had whitish, watery diarrhea, vomiting and slight fever and recovered in 3 to 5 days. The faecal specimens were collected the day after the onset of the disease and stored at --80°C until use. All the specimens were shown by electron microscopy to contain rotavirus particles when examined by the method described previously (9).Cultures of MA104 cells were prepared in 110 × 10 m m tubes. The growth medium used was Eagle's minimum essential medium (MEM) containing 10 per cent tryptose phosphate broth (TPB) (Difco), 10 per cent calf serum, 100 units/ml penicillin, 100 ~g/ml streptomycin and t ~g/mI fungizone, and the maintenance medium (MM) was MEM containing 10 per cent TPB, 0.5 per cent sodium glut,-0304-8608/81/0069/0155/$ 01.20

SummaryThe pathogenicity for mice of nine strains of mouse hepatitis virus was studied in mice free from the virus by the intracerebral, intraperitoneal, intravenous and intranasal routes of inoculation.

Outbreaks of an acute febrile disease of cattle occurred in Japan in 1959 and 1960. Its occurrence was limited in late summer and autumn, and in Kyushu, Shikoku and Honshu roughly south of 37 degrees north latitude, suggesting a close correlation of the incidence with the climatic conditions, hence a possibility of the presence of arthropod vector. The disease was characterized by fever and lesions affecting the mucous membrane and skin, musculature and vascular system. Degeneration of striated muscles was observed in the esophagus, larynx, pharynx, tongue and skeletal muscular system. Edema and hemorrhage were marked in the mouth, lips, abomasum, coronets etc., occasionally followed by degeneration of the epithelium leaving erosions or ulcerations. Severe lesions affecting the esophageal and laryngopharyngeal musculature caused deglutitive difficulty which in turn resulted in dehydration and emaciation, and occasionally in aspiration pneumonia, constituting the major causes of death of the affected animals. These findings indicate that the disease resembles bluetongue in sheep and cattle. The clinical materials obtained from natural cases induced a clinical illness when inoculated into calves, and the disease was transmitted serially in calves by intravenous inoculation of the blood obtained at the height of febrile reaction. The experimentally produced disease was clinically and pathologically indistinguishable from the natural disease.