Preface

 

Onchocerciasis is a disease caused by a parasite called Onchocerca volvulus, which damages the skin and produce serious eye disease causing blindness, so that it was called “river blindness”. The parasite is transmitted from person to person through the bite of the vector blackflies of Simulium spp. inhabiting in the endemic foci. The advent of Ivermectin (Mectizan^®, provided free in terms of the Mectizan Donation Program, Merck & Co. Inc.), an effective microfilaricide used in veterinary field on a large scale, has greatly improved the prospects for the control or elimination of onchocerciasis in many areas. Administration of Ivermectin once or twice a year in a single oral dose, reduces the number of microfilariae of Onchocerca volvulus in the skin to lower level required for effective transmission by Simulium spp.

Rodolfo Robles Valverde (1878–1939), a Guatemalan physician who in 1915 discovered the onchocerciasis, was born in Quetzaltenango, Guatemala. He studied at the University in Rouen and later at the Sorbonne (1904). In 1905, he joined the Faculty of Medicine of the National University of San Carlos of Guatemala and was awarded in 1922 PhD at the University of Paris, where he learned more malariology, public health and mycology.

Robles clarified that the so called coastal erysipela, tumors (onchocercoma) and disorders of the eye were due to the infection of Onchocerca volvulus a species of filaria, whose mode of transmission was unknown. He described the epidemiological aspect, too. In fact, he realized that onchocerciasis was not a mild disease of the skin, but a severe one leading to blindness. Additionally, he discovered that the disease was transmitted by the black fly of Simulium sp., the only blood-sucking insect in the studied disease. Therefore, for the honor of the discoverer of onchocerciasis, this disease is now called as “Mal de Robles”.

This disease is now prevalent in 37 countries: 30 in Africa, 1 in the Arabian Peninsula (Yemen) and 6 in Latin America (Mexico, Guatemala, Colombia, Venezuela, Ecuador and Brazil). Approximately 119 million people in the world live in areas where the disease is present. 17.7 million people are at risk of getting sickness, of which about 270,000 are blind (second cause of blindness in the world) and another 500,000 have severe visual problems (WHO).

For the elimination of the disease, the Pan American Health Organization (OEPA) verified by country and not foci. In Guatemala, four foci (Escuintla, Santa Rosa, Huehuetenango and Central) were identified. The focus of Santa Rosa was the first focus installed by the mass treatment with Mectizan^® in 2007 and the central focus (Suchitepéquez, Chimaltenango and Sololá) was the last in 2010. After three years of surveillance post treatment (VEPT), it was shown that the transmission was interrupted successfully in 2014. Therefore, it was concluded that human onchocerciasis has been eliminated from Guatemala. The OEPA recommended to PAHO / WHO the verification of the onchocerciasis elimination in 2015 as the fourth country in America after Colombia, Ecuador and Mexico. They accepted the recommendation.

Before this story, during the period between 1975 and 1983, we engaged in the research for the control of onchocerciasis in Guatemala with the Official development Assistance (ODA) program of Japan. Dr. Horacio Figueroa, a professor emeritus of National San Carolos University, rolled an important play to introduce Japanese technical cooperation. This project produced successful strategy for the vector control of onchocerciasis. For this the Government of Guatemala appreciates so much Japan’s cooperation which assisted greatly the OEPA project. As this year marks the 100th anniversary of the discovery of Roble disease, onchocerciasis, I fully congratulate the publication of this special issue.