Canine-Origin G3P[3] Rotavirus Strain in Child with Acute Gastroenteritis

Infection by an animal-like strain of rotavirus (PA260/97) was diagnosed in a child with gastroenteritis in Palermo, Italy, in 1997. Sequence analysis of VP7, VP4, VP6, and NSP4 genes showed resemblance to a G3P[3] canine strain identified in Italy in 1996. Dogs are a potential source of human viral pathogens.

Infection by an animal-like strain of rotavirus (PA260/97) was diagnosed in a child with gastroenteritis in Palermo, Italy, in 1997. Sequence analysis of VP7, VP4, VP6, and NSP4 genes showed resemblance to a G3P [3] canine strain identifi ed in Italy in 1996. Dogs are a potential source of human viral pathogens.
G roup A rotaviruses are enteric pathogens of humans and animals. Rotaviruses usually exhibit host species restriction, although interspecies transmission or reassortment between animals and humans viruses can occur (1). Sequence analysis of the genes that code for the 2 outer capsid proteins VP7 and VP4, for the inner capsid protein VP6, and for the nonstructural protein NSP4 is useful for gathering epidemiologic information and tracing the origin of unusual rotavirus strains. To date, 15 VP7 genotypes (G types 1-15), 27 VP4 genotypes (P types [1]-[27]), 4 VP6 subgroup specifi cities (SGs I, II, I+II, and nonI/nonII), and 5 NSP4 genotypes (A-E) have been established in human and animal group A rotaviruses (1,2). Human rotaviruses usually exhibit G1, G3, G4, and G9 types in association with P [8] type, SGII specifi city, and NSP4 B type; G2 rotaviruses are more often associated with P [4] type, SGI specifi city, and NSP4 A type (1). By polyacrylamide gel electrophoresis (PAGE), most animal SGI and SGII and human SGII rotavirus strains display a "long" pattern of migration (e-type) of the 11 dsRNA genomic segments; almost all SGI human rotavirus strains possess a "short" e-type (1).
A number of strains with unusual VP7 and VP4 genes, regarded as animal-like, have been sporadically identifi ed in humans and have acquired epidemiologic relevance in some geographic areas (3). Dogs are regarded as vectors of viral, bacterial, or parasitic zoonoses for persons of all ages, but risks for transmission of enteric viruses are almost ignored. However, early in the study of rotavirus epidemiology, symptomatic and asymptomatic infections by canine/feline-like rotavirus strains (HCR3A, HCR3B, Ro1845), characterized as G3P5A [3], long e-type and SGI, were identifi ed in young children (4,5).

The Study
In February 1997, rotavirus infection was diagnosed (by PAGE analysis) in a 2-year-old child hospitalized with severe acute diarrhea at the "G. Di Cristina" Children's Hospital of Palermo. The virus, PA260/97, exhibited a long e-type and was recognized by an SG-specifi c monoclonal antibody (MAb) and by a VP7-specifi c MAb as SGI and G3 (6). Accordingly, strain PA260/97 displayed a genetic/antigenic constellation that is usually observed in animal-like viruses. For confi rmation of the initial antigenic characterization and information about the VP4 (P) genotype, strain PA260/97 was characterized at the molecular level. By PCR genotyping of the VP7 and VP4 genes with panels of primers specifi c for various human G and P types (3,7,8), the VP7 was characterized as G3 and the VP4 was untypeable. To characterize strain PA260/97 in more detail, we determined the sequence of the VP7, VP4 (VP8*), VP6, and NSP4 genes. We also determined the VP7, NSP4, and VP6 sequences of human strain PAH101/97 (G3P [8], SGII, long e-type), detected in Palermo in the same year, as well as the sequences of the VP8*, VP6, and NSP4 genes of 2 G3P [3], SGI, long e-type strains, RV 198/95, and RV 52/96, isolated from dogs in Italy in 1995 and 1996, respectively (9).
Canine rotavirus infection is considered a minor disease in young dogs (pups) because it is usually mild or unapparent; however, serologic investigations have shown a high prevalence of antibodies to rotavirus in adult dogs (15). Previous documented examples of infections in humans by canine-like rotavirus strains have been associated with either asymptomatic (strains HCR3A and HCR3B) or symptomatic (strain Ro1845) clinical forms of disease (4,5,12). Strain PA260/97 in the 2-year-old child was associated with enteritis severe enough to require hospitalization. Therefore, the results of this study reinforce the hypothesis that canine-like rotaviruses may be able to not only cross the species barriers but also to induce severe disease forms in children. The lack of systematic surveillance of rotavirus infection in small animals (e.g., dogs and cats) and the fact that most rotavirus infections in such animals  may go undetected hinder the ability to establish fi rm epidemiologic connections. In conclusion, complementing the human rotavirus surveillance programs with surveillance in animals is paramount to understanding the global ecology of rotaviruses and to identifying and characterizing interspecies transmission events and virus evolution. This study was supported by the Ministero dell'Istruzione, dell'Università e della Ricerca (Italian Ministry of Education, University and Research) (Fondi di Ateneo ex 60%).
Dr De Grazia is a microbiology specialist and research assistant at the University of Palermo, Dipartimento di Igiene e Microbiologia "G. D'Alessandro." Her primary research interests are microbial typing, viral enteric pathogens, and viral epidemiology.