Abstract. Since the first reported epidemic of dengue in Pemba, the capital of Cabo Delgado province, in 1984Delgado province, in -1985 further cases have been reported in Mozambique. In March 2014, the Provincial Health Directorate of Cabo Delgado reported a suspected dengue outbreak in Pemba, associated with a recent increase in the frequency of patients with nonmalarial febrile illness. An investigation conducted between March and June detected a total of 193 clinically suspected dengue patients in Pemba and Nampula, the capital of neighboring Nampula Province. Dengue virus-type 2 (DENV-2) was detected by reverse transcriptase polymerase chain reaction in sera from three patients, and 97 others were classified as probable cases based on the presence of DENV nonstructural protein 1 antigen or anti-DENV immunoglobulin M antibody. Entomological investigations demonstrated the presence of Aedes aegypti mosquitos in both Pemba and Nampula cities.The four dengue virus-types (DENV-1-4) are arthropodborne RNA viruses belonging to the family Flaviviridae and transmitted by Aedes spp. mosquitos.1 Dengue is endemic in tropical and subtropical regions where an estimated 390 million infections occurred in 2010.2,3 Approximately 50% of the world's population lives in areas at risk for DENV infection. 4 Although current estimates suggest that subSaharan Africa carries 16% of the annual worldwide burden of dengue, the epidemiology of dengue in the region is poorly understood and the disease remains neglected. 4,5 Reasons for the under-recognition and underreporting of dengue in subSaharan Africa include a lack of clinical awareness, over diagnosis of malaria, limited laboratory diagnostic capability, and weak surveillance systems. 6 In recent years, an increasing number of dengue outbreaks have been identified in Africa, including Angola, Kenya, Ethiopia, and Tanzania. [7][8][9][10] In Mozambique, the last known outbreak of dengue occurred in [1984][1985] in Pemba, the capital of Cabo Delgado Province, in northern Mozambique, caused by In March 2014, the Cabo Delgado Provincial Health Authority reported a cluster of patients with nonmalarial febrile illness in Pemba, suspected as dengue. This report describes findings from the outbreak investigation.The investigation was conducted in two phases, with the initial phase from March 15-28, 2014 focused on patients hospitalized at Pemba Provincial Hospital in Cabo Delgado Province, with unknown febrile illness suspected of dengue. A suspected dengue case was defined as a patient with acute febrile illness with a negative malaria test result, and at least two or more of the following manifestations: headache, retroorbital pain, myalgia, arthralgia, rash, hemorrhagic manifestations, or leucopenia. During phase one, blood specimens were collected from 20 patients with suspected dengue and tested at the national reference laboratory for DENV nonstructural protein 1 (NS1) antigen and anti-DENV immunoglobulin M (IgM) antibody by enzyme immunoassay (EIA) (Panbio Capture ELISA, Alere, ...