Investigation of Lethal Concurrent Outbreak of Chlamydiosis and Pigeon Circovirus in a Zoo

Abstract

During the spring, an outbreak of sudden death involving 58 birds occurred in a zoo. Histopathological examinations revealed variable numbers of intracytoplasmic basophilic microorganisms in the macrophages, hepatocytes, and renal epithelium of most birds, along with occasional botryoid intracytoplasmic inclusion bodies within histiocytes in the bursa of Fabricius. Based on the results of histopathological examinations, immunohistochemical staining, transmission electron microscopy, and polymerase chain reactions, genotype B Chlamydia psittaci infection concurrent with pigeon circovirus (PiCV) was diagnosed. A retrospective survey, including two years before the outbreak and the outbreak year, of C. psittaci and PiCV infections of dead birds in the aviaries, revealed that the outbreak was an independent episode. The findings of this study indicate that concurrent infection with C. psittaci and PiCV might lead to lethal outbreaks of chlamydiosis, particularly Streptopelia orientalis. In addition, persistently monitoring both pathogens and identifying potential PiCV carriers or transmitters might also help prevent lethal disease outbreaks.

State-of-the-Art Avian Viruses Research in Asia

“…Another strategy has been tested in which a nonlethal virus was inserted with a lethal viral structure protein. A vaccine against highly lethal avian bornavirus was developed using recombinant virus to protect parrots from Newcastle disease virus [90][91][92].…”

“…Within the first decade after the short report of Schmidt [1], retrieved records showed detection of the virus in several other countries including Northern Ireland [16,34,69,70], Germany [15,44], Italy [31,71], France [72], Belgium [30,33,34], and Japan [21,38]. Meanwhile, between 2003 and 2012, researchers in Czech Republic [29,32], Poland [36,58,67,[73][74][75][76][77][78][79][80], Denmark [30], Slovenia [81,82], Hungary [66,83], United Arab Emirates [84], Libya [85], Nigeria [83,86], and Taiwan [59,[87][88][89][90][91][92][93] reported first local detections of PiCV. Lastly, during the most recent decade of PiCV research, new publications and reports were also produced from Brazil [40], Iran [94,95], Iraq [39], and Turkey [96].…”

Pigeon Circovirus over Three Decades of Research: Bibliometrics, Scoping Review, and Perspectives

“…Within the first decade after the short report of Schmidt [ 1 ], retrieved records showed detection of the virus in several other countries including Northern Ireland [ 16 , 34 , 69 , 70 ], Germany [ 15 , 44 ], Italy [ 31 , 71 ], France [ 72 ], Belgium [ 30 , 33 , 34 ], and Japan [ 21 , 38 ]. Meanwhile, between 2003 and 2012, researchers in Czech Republic [ 29 , 32 ], Poland [ 36 , 58 , 67 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 ], Denmark [ 30 ], Slovenia [ 81 , 82 ], Hungary [ 66 , 83 ], United Arab Emirates [ 84 ], Libya [ 85 ], Nigeria [ 83 , 86 ], and Taiwan [ 59 , 87 , 88 , 89 , 90 , 91 , 92 , 93 ] reported first local detections of PiCV. Lastly, during the most recent decade of PiCV research, new publications and reports were also produced from Brazil [ 40 ], Iran [ 94 , 95 ], Iraq […”

“…Moreover, a recent study involving outbreak of Chlamydia psittaci in aviaries in Taiwan surprisingly detected PiCV in 12 species of birds ( Aix galericulata , Cygnus melancoryphus , Caloenas nicobarica , Columba pulchricollis , Goura cristata , Ocyphaps lophotes , Spilopelia chinensis , Streptopelia orientalis , Pavo cristatus , Threskiornis aethiopicus , Phoenicopterus chilensis , Phoenicopterus ruber ) coming from five different orders by amplifying the partial cap gene of the virus. The authors have correlated the lethal outbreak of chlamydiosis to a concurrent circulation of PiCV which may have “play[ed] a key role in augmenting [the] disease progression” although further proof certainly is needed [ 92 ]. Moreover, PiCV detection is not only limited to different species of birds as it was also detected in ticks parasitizing camels and sheep from Inner Mongolia.…”

“…What this proposal is trying to resolve and formalize is the importance of and necessity for PiCV infection to pigeon health and the development of a particular disease. In extension, the proposal recognizes the pathogenicity of PiCV, perhaps, best evidenced by the demonstration of the virus’ apoptotic ability to B lymphocytes confirming its immunosuppressive function [ 52 , 92 ].…”