Poultry oncogenic retroviruses and humans

Area of Science:

• Virology
• Oncology
• Public Health

Background:

• Avian leukosis/sarcoma viruses (ALSV) and reticuloendotheliosis viruses (REV) are common in poultry and cause tumors in birds.
• These viruses are widespread, leading to near-universal human exposure through poultry products and eggs.
• ALSV and REV can infect and transform mammalian cells, including human cells, in vitro and induce tumors in various mammals.

Purpose of the Study:

• To comprehensively review the carcinogenic potential of ALSV and REV in humans.
• To assess the risk of cancer in humans due to exposure to these avian viruses.

Main Methods:

• Review of existing virological, serological, and epidemiological studies.
• Analysis of in vitro and in vivo data on mammalian cell transformation and tumor induction.
• Evaluation of methodological limitations in previous human serological studies.

Main Results:

• Most human serological studies have yielded negative results, partly due to methodological issues.
• Virological evidence suggests a conceivable carcinogenic potential in humans, albeit at a much lower level than in chickens.
• Some epidemiological data hint at a possible association between poultry exposure and human cancer, requiring further investigation.

Conclusions:

• ALSV and REV demonstrate carcinogenic potential in mammals, including primates.
• The risk of these viruses causing cancer in humans is currently unknown but presumed to be low.
• Definitive studies are necessary to conclusively rule out any carcinogenic risk to humans from these avian viruses.