Histomoniasis, also known as "blackhead disease", is a parasitic disease that affects birds, especially turkeys and chickens. This disease is caused by the protozoan Histomonas meleagridis, which infects the cecum and liver of the host bird. There are various synonyms for the word "histomoniasis", including "infectious enterohepatitis", "meleagridosis", and "blackhead." These terms are used interchangeably to refer to the same disease that can adversely affect birds' health and compromise the quality of their meat. Histomoniasis is transmitted via a fecal-oral route and can affect birds of all ages. It can lead to significant economic losses for poultry farmers and is a significant concern in the commercial poultry industry.