Case-Cohort Study of Cancers in Excess in Poultry Workers

描述（由申请人提供）：某些逆转录病毒和疱疹病毒自然和通常感染鸡和火鸡并导致癌症。这些病毒包括一些在动物中已知的最有效的致癌剂。人类几乎普遍接触这些病原体，并通过以下途径发生：1）接触活家禽; 2）接触其血液和生肉和蛋类产品; 3）摄入生的或未充分煮熟的禽肉和蛋类; 4）职业性接触，如饲养、屠宰、加工和销售生家禽产品、兽医、家禽检查员、厨师、实验室科学家等; 5)接种通过在鸡胚中培养疫苗病毒生产的疫苗，如麻疹、腮腺炎、流感和黄热病疫苗，可能含有这些致癌病毒的外源性和内源性形式。众所周知，这些病毒可以在体外感染人类细胞并将其转化为癌细胞，并且在实验中，这些病毒可以感染灵长类动物并导致肿瘤。此外，人类血清学试验明确表明，这些病毒在一般人群中广泛感染。然而，目前缺乏病毒导致人类癌症的确切证据，部分原因是缺乏对暴露个体癌症风险的分析流行病学研究。我们假设，如果这些病毒在人类中引起癌症，那么在家禽屠宰和加工厂的工人中最明显，他们对这些因子的人类暴露最高。因此，我们在这些工人的三个独立队列中进行了癌症死亡率研究。结果表明16个癌症部位的过度发生。拟议的调查是一项病例队列研究，其中13个地点调查这些病毒在其病因学中的作用，同时控制并同时调查其他潜在的职业和非职业致癌暴露的作用。传染病是NIOSH在其职业安全与健康研究计划中确定的优先领域之一。公共卫生相关性：某些病毒自然感染鸡和火鸡并导致癌症。人类通常通过接触活鸡和火鸡及其血液和分泌物，或通过食用生的或未充分煮熟的家禽产品（包括鸡蛋）而暴露于这些病毒。此外，当人类接种用鸡蛋生产的疫苗时，如麻疹和腮腺炎疫苗，就会暴露于这些病毒。然而，目前尚不清楚这些病毒是否会导致人类癌症。为了找到答案，我们正在对那些在宰杀和加工鸡和火鸡的地方工作的人进行研究，他们是人类接触这些病毒最多的人。因此，如果这些病毒导致人类癌症，这应该很容易在这组中看到。这项研究还将确定这些工人在工作中接触的其他物质，例如吸烟时的烟雾或包装肉类时的烟雾，这些烟雾含有已知会导致人类癌症的化学物质，也会导致这些工人患癌症。

DESCRIPTION (provided by applicant): Certain retroviruses and herpesvirus naturally and commonly infect and cause cancer in chickens and turkeys. These viruses include some of the most potent cancer-causing agents known in animals. Human exposure to these agents is virtually universal, and occurs through: 1) contact with live poultry; 2) contact with their blood and raw meat and egg products; 3) through ingestion of raw or inadequately cooked poultry meat and eggs; 4) occupationally in jobs such as raising, slaughtering, processing, and sale of raw poultry products, veterinarians, poultry inspectors, cooks, laboratory scientists, etc.; 5) inoculation with vaccines manufactured by growing the vaccine virus in chicken embryos such as measles, mumps, influenza, and yellow-fever vaccines, that may contain exogenous and endogenous forms of these oncogenic viruses. It is known that the viruses can infect human cells in vitro and transform them into cancerous cells, and experimentally the viruses can infect and cause tumors in primates. Furthermore, serological tests in humans clearly indicate widespread infection of the general population with these viruses. However, definitive proof that the viruses cause cancer in humans is currently lacking partly because of the absence of analytic epidemiologic studies of cancer risk in exposed individuals. We hypothesize that if these viruses cause cancer in humans, it will be most readily evident in workers in poultry slaughtering & processing plants who have the highest human exposure to these agents. Accordingly, we conducted cancer mortality studies in three separate cohorts of these workers. The results indicate excess occurrence of 16 cancer sites. The proposed investigation is a case-cohort study of 13 of these sites to investigate the role of these viruses in their etiology, while controlling for and concurrently investigating the roles of other potential occupational and non-occupational carcinogenic exposures. Infectious diseases, is one of the priority areas identified by NIOSH in its Occupational Safety and Health Research program. Public Health Relevance: Certain viruses naturally infect and cause cancer in chickens and turkeys. Humans are commonly exposed to these viruses from contact with live chickens and turkeys and their blood and secretions, or from eating raw or inadequately cooked poultry products, including eggs. Also, humans are exposed to these viruses when they are vaccinated with vaccines manufactured using chicken eggs, such as measles and mumps vaccines. However, it is not known if these viruses cause cancer in humans. To find out, we are conducting a study of persons who work in places where chickens and turkeys are killed and processed, who have the highest human exposure to these viruses. Thus if these viruses cause cancer in humans this should be easily seen in this group. The study will also determine if other agents which these workers are exposed to at work such as smoke during the smoking of meat or fumes during wrapping of meat that contain chemicals which are known to cause cancer in humans, are also causing cancer in these workers.