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Pasteurella multocida is a causative agent of many major diseases of which haemorrhagic septiciemia (HS) in cattle & a buffalo is responsible for significant losses to livestock sector in India and south Asia. The disease outcome is affected by various host- and pathogen-specific determinants. Several bacterial species-specific putative virulence factors including the capsular and virulence associated genes have been proposed to play a key role in this interaction. A total of 23 isolates of P. multocida were obtained from 335 cases of various clinically healthy and diseased cattle. These isolates were examined for capsule synthesis genes (capA, B, D, E and F) and eleven virulence associated genes (tbpA, pfhA, toxA, hgbB, hgbA, nanH, nanB, sodA, sodC, oma87 and ptfA) by PCR. A total of 19 P. multocida isolates belonging to capsular type B and 4 of capsular type A were isolated. All isolates of capsular type B harboured the virulence associated genes: tbpA, pfhA, hgbA, sodC and nanH, coding for transferrin binding protein, filamentous hemagglutinin, haemoglobin binding protein, superoxide dismutase and neuraminidases, respectively; while isolates belonging to capsular type A also carried tbpA, pfhA, hgbA and nanH genes. Only 50 % of capsular type A isolates contained sodC gene while 100 % of capsular type B isolates had sodC gene. The gene nanB and toxA were absent in all the 23 isolates. In capsular type A isolates, either sodA or sodC gene was present & these genes did not occur concurrently. The presence of virulence associated gene ptfA revealed a positive association with the disease outcome in cattle and could therefore be an important epidemiological marker gene for characterizing P. multocida isolates.

To study genetic diversity and occurrence of Chlamydophila psittaci, a total of 1,147 samples from 11 avian orders including 53 genera and 113 species of feral and captive birds were examined using ompA gene based nested PCR. Three types of chlamydiae: C. psittaci (94.12%), C. abortus (4.41%) and unknown Chlamydophila sp. (1.47%) were identified among 68 (5.93%) positive samples (Psittaciformes‐59, Ciconiiformes‐8 and Passeriformes‐1). Based on nucleotide sequence variations in the VD2 region of ompA gene, all 64 detected C. psittaci strains were grouped into 4 genetic clusters. Clusters I, II, III and IV were detected from 57.35%, 19.12%, 10.29% and 7.35% samples respectively. A single strain of unknown Chlamydophila sp. was found phylogenetically intermediate between Chlamydophila species infecting avian and mammalian hosts. Among Psittaciformes, 28 out of 81 tested species including 10 species previously unreported were found to be chlamydiae positive. Chlamydiosis was detected among 8.97% sick and 48.39% dead birds as well 4.43% clinically normal birds. Therefore, it was observed that though various genetically diverse chlamydiae may cause avian chlamydiosis, only a few C. psittaci strains are highly prevalent and frequently associated with clinical/subclinical infections.

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Infectious keratoconjunctivitis (IKC) is a highly contagious ocular inflammatory condition, which is often reported in domestic small and large ruminants. Multiple infectious aetiologies are reported to be involved, but information about the role of certain fastidious bacterial pathogens such as chlamydiae and mycoplasmas is limited in India. Hence, this study was performed to determine the role of these pathogens and their identification by molecular approach. A total of 53 samples from 31 ovine, 14 caprine and eight bovine having clinical symptoms were collected and tested using species-specific PCR tests for chlamydiae and mycoplasmas followed by nucleotide sequence analysis. The results showed 77.41, 14.29 and 25% samples were chlamydiae positive in ovine, caprine and bovine, respectively, whereas 41.93, 14.29 and 37.5% prevalence of mycoplasma infection was detected in ovine, caprine and bovines, respectively. Chlamydophila abortus, Chlamydophila psittaci, Mycoplasma arginini and Mycoplasma hyorhinis were detected from tested samples. To the best of our knowledge, this is the first time these species are identified in IKC cases from India. Coinfection of both chlamydial and mycoplasmal species was detected in eight IKC cases of ovine which suggest synergistic roles played by both chlamydiae and mycoplasma in IKC samples.

SummaryChlamydia suis has been detected in numerous disease conditions of pigs, particularly in eye infections. This study examined recurring conjunctivitis cases in five commercial pig farms in Japan. 40.5% of the cases were identified as Chlamydia positive using impression cytology of ocular smears and a genus-specific direct fluorescent antibody. C. suis was detected in 59.5% of the samples using PCR tests showed multiple 16S-23S rRNA ISR sequence types of C. suis. Multiple genotypes were found circulating in four of five farms. All 20 detected strains and 25 previously reported C. suis strains were grouped into four clusters. Japanese C. suis strains were closely related to American and European strains indicating wide distribution of these genetically variant strains. This study is the first to show multiple and genetically diverse C. suis strain associations in pig conjunctivitis.

ABSTRACT. Although birds infected with avian polyomavirus (APV) subclinically could be a source of infection, no epidemiological studies of APV in psittacine birds have been reported in Japan. In the present study, we investigated subclinical morbidity rate of APV in imported and domestically bred psittacine birds by polymerase chain reaction (PCR). Of 402 live birds from which blood or feather samples were taken between April, 2003 and March, 2004, 11 (2.7%) were found to be APV positive. The DNA sequences of the APV t/T antigen region were determined for five APV-positive randomly selected samples and were found to be conserved. KEY WORDS: avian polyomavirus, budgerigar fledgling disease, epidemiology.

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