Wirth Wytamma, Forzán María J, Schwarzkopf Lin, Ariel Ellen
James Cook University, Townsville, QLD, Australia.
Long Island University, Brookville, NY.
Vet Pathol. 2023 Jan;60(1):139-150. doi: 10.1177/03009858221122591. Epub 2022 Sep 9.
Ranaviruses have been detected in over 12 families of reptiles including many genera of turtles, tortoises, and terrapins, but the pathogenesis of these infections is still poorly understood. Krefft's river turtle hatchlings ( = 36; ) were inoculated intramuscularly with Bohle iridovirus (BIV, , isolate) or saline, and euthanized at 9 timepoints (3 infected and 1 control per timepoint) over a 24-day period. Samples of lung, liver, kidney, and spleen were collected for quantitative polymerase chain reaction (PCR); internal organs, skin, and oral cavity samples were fixed for histopathological examination. The earliest lesions, at 8 days postinoculation (dpi), were lymphocytic inflammation of the skin and fibrinoid necrosis of regional vessels at the site of inoculation, and mild ulcerative necrosis with lymphocytic and heterophilic inflammation in the oral, nasal, and tongue mucosae. Fibrinonecrotic foci with heterophilic inflammation were detected in spleen and gonads at 16 dpi. Multifocal hepatic necrosis, heterophilic inflammation, and occasional basophilic intracytoplasmic inclusion bodies were observed at 20 dpi, along with ulcerative lymphocytic and heterophilic tracheitis and bronchitis. Tracheitis, bronchitis, and rare bone marrow necrosis were present at 24 dpi. Of the viscera tested for ranaviral DNA by PCR, the liver and spleen had the highest viral loads throughout infection, and thus appeared to be major targets of viral replication. Testing of whole blood by qPCR was the most-effective ante-mortem method for detecting ranaviral infection compared with oral swabs. This study represents the first time-dependent pathogenesis study of a ranaviral infection in turtles.
在超过12个爬行动物科中都检测到了蛙病毒，其中包括许多龟类、陆龟和水龟属，但这些感染的发病机制仍知之甚少。将36只克氏河龟幼龟肌肉注射博勒虹彩病毒（BIV， ，分离株）或生理盐水，并在24天内的9个时间点（每个时间点3只感染龟和1只对照龟）实施安乐死。采集肺、肝、肾和脾的样本用于定量聚合酶链反应（PCR）；将内部器官、皮肤和口腔样本固定用于组织病理学检查。接种后8天（dpi）最早出现的病变是接种部位皮肤的淋巴细胞炎症和局部血管的纤维蛋白样坏死，以及口腔、鼻腔和舌黏膜的轻度溃疡性坏死伴淋巴细胞和嗜异性粒细胞炎症。在16 dpi时，在脾脏和性腺中检测到伴有嗜异性粒细胞炎症的纤维蛋白坏死灶。在20 dpi时观察到多灶性肝坏死、嗜异性粒细胞炎症和偶尔出现的嗜碱性胞质内包涵体，同时伴有溃疡性淋巴细胞和嗜异性粒细胞气管支气管炎。在24 dpi时出现气管支气管炎和罕见的骨髓坏死。通过PCR检测蛙病毒DNA的内脏中，肝脏和脾脏在整个感染过程中的病毒载量最高，因此似乎是病毒复制的主要靶器官。与口腔拭子相比，通过qPCR检测全血是检测蛙病毒感染最有效的生前方法。本研究是首次对龟类蛙病毒感染进行的时间依赖性发病机制研究。
