As the medical officer in the general military hospital in Ponce, he was the first to describe and successfully treat North American hookworm in 1899.

[citation needed] Because of his clinical investigations into the anemia caused by hookworm infestation, Ashford was inspired to organize and conduct a parasite treatment campaign.

It cured approximately 300,000 persons (one-third of the Puerto Rico population) and reduced the death rate from this anemia by 90 percent.

"[2] In 1911, Ashford together with doctors Isaac Gonzalez Martinez, Pedro Gutiérrez Igaravides and Walter King, proposed that the local government create an Institute of Tropical Medicine to further the research initiated by the Anemia Commissions.

Senator Barceló became interested in the idea and, on June 23, 1924, he sponsored the legislation which provided Governor Horace Towner, with the prerequisite funding for the school.

Located in Puerta de Tierra, San Juan, the school's building is one of the few examples of the Neo-Plateresque architectural style on the Island.

[3] Having completed a 30-year Army career, Ashford assumed a full-time faculty position at the school and continued his interest in tropical medicine.

In May 1930, the University of Puerto Rico offered two degrees of Master of Arts for the students who continued their education and work at the School of Tropical Medicine.