Evaluation of Rotavirus Infection and Diarrhea in Iowa Commercial Pigs Based on an Epidemiologic Study of a Population Represented by Diagnostic Laboratory Cases

Abstract

Abstract. Group A, B, and C rotaviruses were identified in 9% (96/1,048) of pig fecal specimens submitted to the Iowa State University Veterinary Diagnostic Laboratory during 1987 and 1988. Six of the rotaviruses were group B, 5 were group C, and the remaining 89% were group A. Of the rotavirus cases with more than 1 serotype, 5 were multiple group A serotypes, 1 involved a group A and B serotype, and 1 included 2 group C serotypes. A retrospective epidemiologic evaluation of pig diarrhea in herds of origin was done using data obtained from the accession records of the rotavirus and 88 matched nonrotavirus pig diarrhea control cases. Herds from which rotavirus cases were derived experienced lower morbidity, mortality, and case fatality rates than matched control herds. The incidence of diarrhea decreased rapidly among all pigs from birth to 3 weeks of age. The peak incidence for piglet diarrhea occurred in February, and a moderate rise occurred in AugustSeptember. Definitive evidence for transmissible gastroenteritis virus was found in 12% of nonrotavirus cases but none of the rotavirus cases in which it was sought. Other pathogenic microorganisms were identified less frequently and inconsistently.Since the discovery of a rotavirus as a cause of diarrhea in calves in 1969, 20 rotaviruses have been recognized as agents in diarrheic disease of swine, 41 and infection is widespread in pigs 4,39,41 In pigs and some other species, a very high incidence of infection may not be unusual. 41 Most rotavirus infections are subclinical in conventionally reared pigs, l1,13,23,41,42 and rotaviruses may be detected in apparently healthy pigs. 10,13,23,32,41,42 Virulence of rotavirus may be affected among other things by virus strain and dose, age of the pig, host environmental and nutritional factors, and concurrent infections. Nursing and weanling pigs experience the greatest morbidity and mortality from rotavirus infections 4,23,35,41 Observed interherd and interlitter rate variations may be the result of colostral antibody differences and the influences of other host, environmental, and agent factors. 40 For example, colostral antibodies have an important protective role for newborn Received for publication October 16, 1993. piglets, but colostrum is neither uniformly ingested nor of consistent protective value. 1 Likewise, the virulence of rotaviruses may be different, 43 and few field strains resemble prototype strains in RNA electropherotypes 15 Rotavirus infection has also been shown to induce villous atrophy and disease in gnotobiotic 4,[8][9][10][17][18][19]31,[36][37][38] and colostrum-deprived 10,17,19 neonatal pigs. The following report is the result of a retrospective epidemiological investigation. The objective of the study was to obtain an Iowa swine population perspective of rotavirus infection and the role of the virus in diarrheic disease as compared with other agents reported in the herds. The collaborative project utilized information obtained from specimens and the accompanying herd histories of ...

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Recombinant porcine rotavirus VP4 and VP4-LTB expressed in Lactobacillus casei induced mucosal and systemic antibody responses in mice

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Detection and molecular characterization of porcine group C rotaviruses in South Korea

“…Moreover, porcine GCRVs are wide spread in swine herds; in limited surveys, antibody prevalence against GCRVs in pigs is 28-70% by 8 weeks of age, increasing with age to reach 79-100% in adult pigs (Saif and Jiang, 1994;Terrett et al, 1987;Tsunemitsu et al, 1992). However, the epidemiological significance of these observations is limited, given the limited number of studies and restricted geographical scope of such investigations (Collins et al, 2008;Janke et al, 1990;Kim et al, 1999;Martella et al, 2007a;Morin et al, 1990;Saif and Jiang, 1994;Saif et al, 1980;Sigolo de San Juan et al, 1986;Will et al, 1994). A possible explanation may be that sensitive tests for detection are not available.…”