ABSTRACT. Fifty-five canine parvovirus type 2 (CPV) samples, 12 fecal specimens and 43 cell culture isolates, were examined for their genetic characteristics of VP2 gene. They were collected from the diseased dogs at various districts of Japan during 27 years from 1980 to 2006. A fragment of VP2 gene was analyzed by restriction fragment length polymorphism assay and DNA sequencing. The original antigenic type 2 of CPV (CPV-2) was no longer found in the samples since 1984, and two antigenic variants CPV-2a and CPV-2b replaced CPV-2 as predominant types for about 5 years from 1982. A new genetic variant of prototype CPV-2a with non-synonymous substitution at the VP2 amino acid residue 297 from Ser to Ala was first detected in 1987. New CPV-2b with the same amino acid substitution at position 297 as new CPV-2a was also detected from the samples collected in 1997. Since then new CPV-2b has been the predominant CPV over the field of Japan. Several additional amino acid substitutions were detected in the VP2 gene of some recent CPV strains. Neither CPV-2c(a), CPV-2c(b), nor "Glu-426" of the antigenic variants previously found outside the country was detected in any samples tested. Reactivity of new CPV-2a and 2b variants against antibodies produced by the current vaccine products was determined by a cross hemagglutination-inhibition test. The recent field CPV isolates reacted more efficiently to the antibodies produced in dogs vaccinated with the new CPV-2b vaccine strain than the conventional CPV-2 vaccine strain.
Chlamydophila felis is a causative agent of acute and chronic conjunctivitis and pneumonia in cats (feline chlamydiosis). Also, C. felis is a suspected zoonotic agent of such diseases as non-Chlamydia trachomatis conjunctivitis in humans, although this is controversial. At present, there is no serodiagnostic system that specifically detects C. felis infection conveniently. Current systems use antigens such as lipopolysaccharide that cross-react with all chlamydia species. In addition, it is difficult to distinguish between cats that are vaccinated with the commercial vaccine against C. felis and cats that are infected with C. felis. Here, we describe a new candidate diagnostic antigen for diagnosis of C. felis infection, CF0218, that was obtained by screening a genomic expression library of C. felis Fe/C-56 with C. felis-immunized serum. CF0218 was a putative transmembrane head (TMH) family protein with bilobed hydrophobic motifs at its N terminus, and orthologues of CF0218 were not found in the Chlamydophila pneumoniae or Chlamydia trachomatis genomes. The recombinant CF0218 was not recognized by antiserum against C. trachomatis, suggesting that CF0218 is C. felis specific. CF0218 transcription during the course of C. felis infection was confirmed by reverse transcription-PCR. By indirect immunofluorescence analysis, CF0218 was colocalized with the C. felis-formed inclusion bodies in the infected cells. The antibody response against CF0218 was elevated following C. felis infection but not by vaccination in experimentally vaccinated and infected cats. These results suggest that CF0218, a novel TMH family protein of C. felis, possesses potential as a C. felis infection-specific diagnostic antigen.The chlamydiae are obligate intracellular bacterial pathogens, possessing a biphasic developmental cycle, consisting of a metabolically inactive infectious elementary body (EB) and a metabolically active noninfectious reticulate body. The bacteria within host cells occupy vacuoles termed inclusions. Chlamydiae cause a range of diseases in various animals, such as humans, birds, and cats. The family Chlamydiaceae is divided into two genera, Chlamydia and Chlamydophila (9). The genus Chlamydia comprises Chlamydia trachomatis (a human conjunctivitis and sexually transmitted disease agent), Chlamydia muridarum (a mouse pneumonia agent), and Chlamydia suis (a pig conjunctivitis agent). The latter genus, Chlamydophila, includes Chlamydophila pneumoniae (an agent for pneumonia and a suspected atherosclerosis agent), Chlamydophila psittaci (an agent for psittacosis), Chlamydophila abortus (a ruminant abortive agent), Chlamydophila caviae (isolated from guinea pigs), Chlamydophila pecorum (infecting ruminants), and Chlamydophila felis (infecting cats) (9).C. felis is a causative agent of feline chlamydiosis, which is characterized by acute and chronic conjunctivitis and pneumonia in cats (40). The prevalence of C. felis in cats with ocular signs or upper respiratory tract diseases (URTD) has been investigated by PCR or by detecti...
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