Since the description of Ancylostoma ceylanicum by Arthur Looss in 1911, and A. braziliense by Gomes de Faria in 1910, the two species were considered synonymous because of their apparent similarities in almost all respects.

However, in 1922 Gordon made an exhaustive comparison from specimens collected in Brazil, South Africa and India, and he failed to identify any distinction.

The anterior end is bent dorsally, which gives the body a characteristic "hooked" or J-shaped appearance, hence the common name hookworm.

If they have burrowed through the skin, they invade the subcutaneous blood vessels, are carried to the lungs, and then move to the intestine via trachea, oesophagus and stomach.

Ancylostoma ceylanicum attaches itself to capillary beds in the small intestine of a host where it feeds on blood and causes anaemia.

[5] Experimental infection of hamsters shows increased antibodies, peripheral cellular immune suppression, which is characterized by a reduction in the total white blood cell count, neutropenia and lymphopenia.

[6] The most serious effects are manifested in children and women of childbearing age displaying chronic intestinal blood loss which may result in iron deficiency, anaemia and hypoalbuminemia.

The Kato-Katz method and molecular techniques such as polymerase chain reaction (PCR) can be used to distinguish hookworm species, but are not always effective at doing so.

[19] It comprises 313 Mb, estimated to be 95% of the full genome, with transcriptomic data throughout infection showing expression of 30,738 predicted protein-coding genes.