虎肿瘤发病情况的调查

An Investigation of Tumor Incidence in a Tiger

肿瘤病在猫科动物中较为多发,为了解虎的整体发病情况、发病规律及病因,通过查阅国内外的研究论文、学位论文、会议论文和兽医诊断记录,经过评估,得到110例有效病例。分析表明,肿瘤共有25个初发部位,包括乳房、生殖道、皮肤、间皮、肝脏、骨骼、血管、子宫、肺、甲状腺、甲状旁腺、睾丸、口腔、神经、淋巴结、胰腺、空肠、直肠、胃、喉、耳、鼻咽、气管、胸腺和纵隔。其中乳腺、生殖道、肝脏和皮肤的病例数最多,分别占41.8%、12.7%、6.4%、5.4%。乳腺、生殖道、子宫肿瘤导致总体上雌虎肿瘤病例数高于雄虎,其他肿瘤发病率性别间差异不大。从年龄看,13~18岁为肿瘤主发阶段。病因包括年龄大、过度肥胖、外伤、饲料烘烤解冻时受到致癌物的污染、环境污染曝露、醋酸甲烯雌醇等避孕药物长期使用、微生物感染等7个方面,但是否与肿瘤的发生直接相关还缺乏实验证据。

Tumors are more commonly found in felids than in other taxa.To investigate the overall incidence and causes of tumors,we compiled 110 documented cases from published literature,dissertations,meeting reports and clinical records from the world（only in English and Chinese）.These cases demonstrated about 25 organs were likely to develop tumors,including mammary gland,genital tract,liver,skin,celothelium,skeleton,blood vessel,uterus,lung,thyroid and parathyroid gland,testes,oral cavity,nerve system,lymph node,pancreas,jejunum,rectum,stomach,throat,ear,nasopharynx,trachea,thymus gland and mediastinum,of which the incidence rates in mammary gland,genital tract,liver and skin were the top four,accounting for 41.8%,12.7%,6.4%and 5.4%,respectively,of all tumor cases.Most tumors occurred in tigers 13-18 years of age.The causes included aging,adiposity,trauma,food contamination by carcinogenic substances,exposure to carcinogenic environment,use of MGA for contraception and microbial infection.Causality was not experimentally documented in most cases.