title: First record of the Asian malaria vector Anopheles stephensi and its possible role in the resurgence of malaria in Djibouti, Horn of Africa.
abstract: Anopheles stephensi is an important vector of urban malaria in India and the Persian Gulf area. Its previously known geographical range includes southern Asia and the Arab Peninsula. For the first time, we report A. stephensi from the African continent, based on collections made in Djibouti, on the Horn of Africa, where this species' occurrence was linked to an unusual urban outbreak of Plasmodium falciparum malaria, with 1228 cases reported from February to May 2013, and a second, more severe epidemic that emerged in November 2013 and resulted in 2017 reported malaria cases between January and February 2014. Anopheles stephensi was initially identified using morphological identification keys, followed by sequencing of the Barcode cytochrome c-oxidase I (COI) gene and the rDNA second internal transcribed spacer (ITS2). Positive tests for P. falciparum circumsporozoite antigen in two of six female A. stephensi trapped in homes of malaria patients in March 2013 are evidence that autochthonous urban malaria transmission by A. stephensi has occurred. Concurrent with the second malaria outbreak, P. falciparum-positive A. stephensi females were detected in Djibouti City starting in November 2013. In sub-Saharan Africa, newly present A. stephensi may pose a significant future health threat because of this species' high susceptibility to P. falciparum infection and its tolerance of urban habitats. This may lead to increased malaria outbreaks in African cities. Rapid interruption of the urban malaria transmission cycle, based on integrated vector surveillance and control programs aimed at the complete eradication of A. stephensi from the African continent, is strongly recommended.
authors.affiliation: Central Institute of the Bundeswehr Medical Service, Department of Medical Entomology/Zoology, PO Box 7340, D-56065 Koblenz, Germany; Institute of Medical Microbiology, Immunology and Parasitology, University Clinics Bonn, D-53105 Bonn, Germany. Electronic address: MichaelFaulde@bundeswehr.org.
authors.forename: Michael K
authors.initials: MK
authors.lastname: Faulde
authors.affiliation: Walter Reed Biosystematics Unit, Entomology Branch, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, MD 20910, USA.
authors.forename: Leopoldo M
authors.initials: LM
authors.lastname: Rueda
authors.affiliation: Department of Infectious Diseases, Epidemiology and Clinical Research, Djiboutian Armed Forces Health Service, Djibouti City, Republic of Djibouti.
authors.forename: Bouh A
authors.initials: BA
authors.lastname: Khaireh
mesh_terms: D000818:Animals; D000852:Anopheles / Q000145:classification* / Q000469:parasitology; D004275:DNA, Ribosomal / Q000235:genetics; D004196:Disease Outbreaks; D015730:Djibouti; D005260:Female; D006801:Humans; D007303:Insect Vectors / Q000145:classification / Q000469:parasitology; D008288:Malaria / Q000453:epidemiology*; D008297:Male
chemical_list: D004275:DNA, Ribosomal
keywords: Anopheles stephensi; Djibouti; Invasive species; Outbreak; Plasmodium falciparum malaria