Historical overview of infantile visceral leishmaniasis in El Agamy, Alexandria, Egypt

•Infantile visceral leishmaniasis in the El Agamy was mainly dependent on the availability of Phlebotomus langeroni and dogs.•The 1982 IVL outbreak was due to the introduction of humans in the sylvatic cycle of the disease owing to initial stages of urbanization.•The completion of urbanization resulted in the disappearance of P. langeroni responsible for the transmission of the disease.•Health impact assessment is of utmost importance when construction activities start in rural Bedouin communities like those found in El Agamy during the 1982 outbreak.•Active surveillance programs for P. langeroni are important in identifying rural communities at risk of transmission of the disease.

Infantile visceral leishmaniasis (IVL) is considered a rare and neglected disease in Egypt. An outbreak of the disease in El Agamy, Alexandria occurred in 1982 although the disease was previously reported 80 years before. Epidemiological and entomological studies were conducted ever since the 1982 outbreak to identify human cases, the parasite, reservoir host and the sand fly vector. Leishmania infantum MON-98, a new and unique zymodeme, was responsible of the disease. Stray dogs acted as the reservoir host and Phlebotomus langeroni was the proven vector. The parasite isolates from human cases were identical to the parasite isolates from the reservoir host and the sand fly vector. The El Agamy focus in 1982 was basically a rural Bedouin setting of recently built cement houses surrounded by lime stone fences. The numbers of human cases of IVL in this area have been declining, with the last reported case in 2005. This coincides with the completion of irregular urbanization of El Agamy which resulted in the disappearance of P. langeroni. In this review, we characterize the old focus of IVL in El Agamy based on published literature to identify factors underlying the appearance and disappearance of the disease.

Graphical abstractView of El Agamy during the 1982 outbreak showing (A) Bedouin settlement with lime stone used as a construction material; (B) stray dog in the Bedouin settlement with new concrete constructions in the background; (C) two story building found next to a Bedouin settlement; (D) new constructions built within the rural environment.Download high-res image (304KB)Download full-size image