Pathology of Neonatal Calf Diarrhea Induced by a Coronavirus-Like Agent

Abstract

Abstract.Lesions induced by a bovine coronavirus-like agent were studied in gnotobiotic and colostrum-fed calves using gross, histologic and electron microscopic procedures. Lesions in gnotobiotic calves were present in the colon, mesenteric lymph nodes and in all segments of the small intestine. Calves killed 4 h after the onset of diarrhea had immunofluorescent epithelial cells on the villi of the small intestine and surface of the colon. Calves killed at 44 h had shortened intestinal villi and cuboidal epithelial cells. The villusto-crypt ratio in the lower small intestine averaged 1 .O compared with 5.3 in a control calf. Immunofluorescent cells were present at the tips of the villi, and at the surface and in the crypts of the colon. Colostrum-fed calves that had serum-neutralizing antibody titers for the coronavirus-like agent developed diarrhea when inoculated orally with the agent. There was good correlation between histologic, immunofluorescent and electron microscopic iindings.Diarrhea occurred in calves 5-21 days old on several ranches during a 1971 field trial of an oral neonatal calf-diarrhea vaccine prepared from a reovirus-like agent [9]. Fecal smears from diarrheic calves were immunofluorescent negative for this agent. Diarrheic fecal material from one of the problem herds inoculated into the duodenum of a hysterotomy-derived colostrum-deprived calf caused diarrhea. Feces from this calf contained coronavirus-like particles. Subsequently diarrhea was produced in eight additional calves [9, 111 with fecal material from a calf with experimentally induced diarrhea. Pathological changes in calves inoculated with the coronavirus-like agent are described.

Evolutionary dynamics of bovine coronaviruses: natural selection pattern of the spike gene implies adaptive evolution of the strains

“…BCoV is the causative agent of neonatal calf diarrhoea (CD), winter dysentery (WD) in adult cattle (Alenius et al, 1991;Mebus et al, 1973;Saif et al, 1988) and respiratory tract disorders in cattle of all ages (Cho et al, 2001;Decaro et al, 2008a;Lathrop et al, 2000). This infection is not effectively controlled in the herds by current commercial vaccines (Saif, 2010).…”

Chronic Shedding of Bovine Enteric Coronavirus Antigen-Antibody Complexes by Clinically Normal Cows

“…Bovine enteric coronavirus (BEC) has been shown to be a primary pathogen in neonatal calf diarrhoea (Mebus et al, 1973). The incidence of BEC-associated enteritis in naturally occurring outbreaks of diarrhoea in young calves has been reported to vary from 15 to 70% Langpap et al, 1979;Marsolais et al, 1978;Morin et al, 1976) and serological evidence indicates that the virus may be widespread (Rodak et al, 1982), at least in Western Canada.…”

Age-Dependent Resistance to Transmissible Gastroenteritis of Swine: III. Effects of Epithelial Cell Kinetics on Coronavirus Production and on Atrophy of Intestinal Villi

“…Acute viral diseases of the small intestine in several species follow a similar sequence of selective cell destruction, leading to variable degrees of villous atrophy and diarrhea, followed by rapid regeneration of villi and the return of normal function. Epizootic diarrhea of infant mice [ 11, lethal intestinal virus infec-tion of mice [3] and diseases caused by a coronavirus [12] and a reovirus-like agent [ l l ] in young calves follow this pattern as does the human disease caused by Norwalk agent [2].…”