[Gustavo Pittaluga and the expedition to study sleeping sickness in the Spanish territories of the Gulf of Guinea (1909)].

Introduction: Sleeping sickness, or human African trypanosomiasis, caused an important mortality at the beginnings of the twentieth century. For this reason the European colonial countries organized several scientific expeditions which contributed decisively to the knowledge of the disease.

Aim: To study the first investigation performed in Spain on African trypanosomiasis and in the field of tropical medicine, which was accomplished by a scientific expedition to the Spanish territories in the Gulf of Guinea organized by Cajal in 1909.

Development: The parasitologist Gustavo Pittaluga, who became one of the most outstanding figures in Spanish medicine and public health during the first third of the twentieth century, commanded the expedition. Other members were Luis Rodriguez Illera and Jorge Ramon Fananas, Cajal's son. Along four months they travelled through the Spanish territories of Guinea, collecting clinical and epidemiological information on sleeping sickness and other diseases, and examining a great number of patients, who had hematological and parasitological studies performed. In the clinical description of the 14 cases of trypanosomiasis studied we have found the first description of the opsoclonus-myoclonus syndrome. A pathological study of the brain was performed in one case. In addition, important entomological studies and experimental investigations on trypanosomiasis were also performed.

Conclusions: This expedition took place in the context of the impulse of renovation of Spanish science headed by Cajal through the Junta de Ampliacion de Estudios, recently created. In the investigations performed in Guinea, Pittaluga demonstrated a high scientific standard in the fields of clinical medicine, hygiene, parasitology and entomology, comparable with other contemporary European studies.