Eucestoda the "broad tapeworm" or "fish tapeworm") and related species. Humans become infected by eating raw, undercooked, or marinated fish acting as a second intermediate or paratenic host harboring metacestodes or plerocercoid larvae. Clinical symptoms are due to the large size of the tapeworm, which often reaches a length exceeding 15 m. The most common symptom is pernicious anemia, caused by the absorption of vitamin B12 by the worm. Other symptoms include various intestinal issues, slight leukocytosis, and eosinophilia. This condition is caused by the plerocercoid larvae of the tapeworm "Spirometra". Humans become infected by drinking contaminated water, eating raw or
Crab-eating macaque findings. One of the most well known examples of experiments on crab-eating macaques is the 1981 Silver Spring monkeys case. In 2014, 21,768 crab-eating macaques were imported in the United States to be used in experimentation. The crab-eating macaque has the third-largest range of any primate species, behind only humans and rhesus macaques. The IUCN Red List categorizes the species as Least Concern, and CITES lists them as Appendix II ("not necessarily threatened with extinction", in which trade must be controlled to avoid use incompatible with their survival). A recent review of their populations suggests a need for better monitoring