Porcine parvovirus (PPV) causes reproductive failure in sows and has spread worldwide. Several new types of porcine parvoviruses have recently been identified in pig herds. The prevalence of five porcine parvoviruses in the Chiangmai area of Thailand was studied. The prevalence in 80 pigs was 53% for PPV (PPV-Kr or -NADL2 being the new abbreviations), 83% for PPV2 (CnP-PARV4), 73% for PPV3 (P-PARV4), 44% for PPV4 (PPV4), and 18% for PBo-likeV (PBoV7). Over 60% of the pigs carried more than three of the five porcine parvoviruses and occurrence together of the two pairs of viral genes, PPV1/PPV3 and PPV2/PBo-likeV were observed. Phylogenetic analyses for PPV2 and PPV3 indicated the existence of only two major clades of PPV2 and one major clade of PPV3.

The porcine parvovirus 2 (PPV2) genome was first identified in 2001 in Myanmar. Recently, the PPV2 genome has been found in several other countries. In this study, the prevalence of PPV2 in Japanese domestic pigs was investigated and found to be 58% (69/120) in healthy domestic pigs and 100% (69/ 69) in sick domestic pigs. Sequencing and phylogenetic analysis of the PCR products of the VP1 gene and an almost full length PPV2 clone indicated that diverged PPV2 strains exist in Japan. Clearly distinct strains of PPV2 were detected in 7 of the 10 pig farms.

Epidemiological surveillance of porcine rotavirus (PoRV) strains was carried out in Chiang Mai Province, Thailand, from 2002 to 2003, and eight rotavirus isolates could not be completely typed by PCR. Of these, six were G3 and one was G4 and displayed a P-nontypeable genotype, while another isolate was both G and P nontypeable. Analysis of a partial VP4 gene of all eight P-nontypeable strains revealed a high degree of amino acid sequence identities (94.7% to 100%), suggesting that they belonged to the same P genotype. Comparison of the amino acid sequences of two representative strains (namely, strains CMP178 and CMP213) with those of 27 other known P genotypes revealed a high degree of amino acid sequence identity with those of P Group A rotaviruses are the most important etiologic agents of severe diarrhea in young children and young animals worldwide. In developing countries, these severe diarrhea cases lead to an estimated 454,000 to 705,000 deaths annually among children under 5 years of age (32). Group A rotaviruses are members of the Reoviridae family with nonenveloped icosahedral particles. The mature virion is formed by three concentric layers of proteins that enclosed a genome of 11 segments of double-stranded RNA. Rotaviruses are classified according to the genetic and antigenic diversity of the two outer capsid proteins, VP4 and VP7. These proteins independently induce type-specific neutralizing antibodies and form the basis of the dual classification of group A rotaviruses into the P (protease sensitive) and the G (glycoprotein) serotypes, respectively (5, 17).Rotaviruses express extensive antigenic and genomic diversities. To date, at least 15 G genotypes and 26 P genotypes have been identified from humans and a variety of animal species (5,22,26,28,30,35,36). Most recently, several groups of investigators have proposed a novel genotype, P[27], which was isolated from diarrheic piglets (18,25,38). Generally, rotaviruses of the same G genotypes share at least 90 to 91% VP7 amino acid sequence identity (11,12,13,16). Rotavirus strains sharing Ն89% VP4 amino acid sequence identities are considered to belong to the same P genotype, while those sharing VP4 amino acid sequence identities of Ͻ89% belong to different genotypes (2, 5, 7). Moreover, the VP8* trypsin-cleavage product of VP4 coding for amino acids (aa) 13 to 250, including the greatest sequence divergent region (aa 71 to 204), correlates well with VP4 genotype specificity (20,21).Several epidemiological studies have demonstrated that among porcine rotaviruses (PoRVs), G3, G4, and G5, are the most common G genotypes and usually associate with the P[6] or P [7] genotype (5,23,39,40). In addition, other G and P types, such as G1, G2, G6, G8, G9, and G10 and P [13] (1,3,5,9,10,16,18,27,29,33,34,37,39,40,41). Accordingly, a comprehensive genotypic characterization of the rotavirus strains circulating in domestic animal populations, especially pigs, is important to define the extent of rotavirus diversity.Rotavirus strains bearing P[13] genotype spe...