Schistosoma japonicum in Ethiopia: Is there a need for tuning schistosomiasis surveillance in Africa?

Abstract

Background: Schistosomiasis is a communicable disease of public health importance in Africa, where Schistosoma mansoni is the most prevalent species. The determinant of the geographic distribution of Schistosoma spp. is a snail, the intermediate host, specific for each species affecting human beings. The accurate identification of cases is essential for the success of control programs in endemic areas. The current work presents a case of Schistosoma japonicum in a woman living in Ethiopia.

Case presentation: In Ethiopia, in an area endemic for S. mansoni, a woman attended a health center, because of joint and abdominal pain. She had never travelled out of the country. She was living in the shore of the Blue Nile River, in Bahir Dar city, which receives a large Chinese population for years. A stool sample was analyzed using Kato Katz, saline concentration and polymerase chain reaction techniques, indicating a co-infection by S. japonicum and S. mansoni.

Conclusions: This study raises awareness about the event, previously noticed, that populations migration is linked to new scenarios of schistosomiasis species. The role of local microscopists becomes of great importance for accurate detection and epidemiological surveillance.

Fig 1. Bahir Dar in the south tip of Tana Lake, Amhara Region, north-western Ethiopia.

Location of the health center (arrow on the top left, Lat; 11⁰ 36’ 00” N, Lon: 037⁰ 23’ 59” E), 0.3 Mi far from Tana Lake, 0.5 Mi far from Blue Nile River (arrow on the top right, Lat; 11⁰ 36’ 00” N, Lon: 037⁰ 24’ 33” E) and 2,4 Mi far from the new bridge over the river (arrow at the bottom, Lat; 11⁰ 35’ 16” N, Lon: 037⁰ 24’ 28” E). Top left of the figure: Location of Bahir Dar in the horn of Africa. Base Layer obtained from the U.S. Geological Survey, National Geospatial Program. (https://earthexplorer.usgs.gov/) (https://www.usgs.gov/faqs/what-are-terms-uselicensing-map-services-and-data-national-map).

Fig 2. Schistosoma spp. eggs found in the sample by a concentration with saline solution (25X objective): Schistosoma japonicum, at the top left, top right, bottom left, bottom center and bottom right pictures (average size: 56 µm x 74 µm); Schistosoma mansoni, at the top, in the center picture.