Transboundary Animal Diseases Centre, Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima, Japan; Department of Animal Hygiene, Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima, Japan; Department of Health Chattogram City Corporation, Chattogram 4000, Bangladesh.
Transboundary Animal Diseases Centre, Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima, Japan; Department of Microbiology and Public Health, Patuakhali Science and Technology University, Babuganj, Barishal 8210, Bangladesh.
Infect Genet Evol. 2022 Aug;102:105297. doi: 10.1016/j.meegid.2022.105297. Epub 2022 May 6.
We investigated the proviral copies and RNA expression in koala retrovirus (KoRV)-infected koalas. To ascertain any variation in viral load by institution, age, sex, or body condition score, we quantified KoRV proviral DNA and RNA loads in captive koalas (n = 37) reared in Japanese zoos. All koalas were positive for KoRV genes (pol, LTRs, and env of KoRV-A) in genomic DNA (gDNA), and 91.89% were positive for the pol gene in RNA. In contrast, the distribution rates of KoRV-B, KoRV-C, KoRV-D, and KoRV-F env genes in gDNA were 94.59%, 27.03%, 67.57%, and 54.05%, respectively. A wide inter-individual variation and/or a significant inter-institutional difference in proviral DNA (p < 0.0001) and RNA (p < 0.001) amounts (copies/10 koala β-actin copies) were observed in Awaji Farm England Hill Zoo koalas, which were obtained from southern koala populations, suggesting exogenous incorporation of KoRV in these koalas. Significant (p < 0.05) age differences were noted in KoRV RNA load (p < 0.05) and median total RNA load (p < 0.001), with loads higher in younger koalas (joeys and juveniles). Thus, the current study provides the distribution of KoRV subtypes in Japanese zoo koala populations and identifies several additional risk factors (sex, age, and body condition) associated with KoRV expression.
我们研究了考拉反转录病毒（KoRV）感染的考拉中的前病毒拷贝数和 RNA 表达。为了确定机构、年龄、性别或身体状况评分对病毒载量的任何影响，我们定量了日本动物园中饲养的感染考拉（n=37）中的 KoRV 前病毒 DNA 和 RNA 载量。所有考拉的基因组 DNA（gDNA）中都存在 KoRV 基因（pol、LTR 和 KoRV-A 的 env），91.89%的考拉在 RNA 中都存在 pol 基因阳性。相比之下，gDNA 中 KoRV-B、KoRV-C、KoRV-D 和 KoRV-F env 基因的分布率分别为 94.59%、27.03%、67.57%和 54.05%。在来自南部考拉种群的英格兰山动物园阿瓦吉农场的考拉中，观察到前病毒 DNA（p<0.0001）和 RNA（p<0.001）量（每 10 个考拉 β-肌动蛋白拷贝的拷贝数）存在广泛的个体间差异和/或显著的机构间差异，这表明这些考拉中存在 KoRV 的外源性整合。在 KoRV RNA 载量（p<0.05）和中位数总 RNA 载量（p<0.001）中观察到显著的年龄差异（p<0.05），年轻的考拉（幼崽和青少年）载量更高。因此，本研究提供了日本动物园考拉种群中 KoRV 亚型的分布情况，并确定了与 KoRV 表达相关的其他几个风险因素（性别、年龄和身体状况）。
