S28 | www.pidj.com The Pediatric Infectious Disease Journal •  Volume 33, Number 1, Supplement 1, January 2014 SUPPLEMENT Background: Rotavirus surveillance was initiated in Ethiopia to esti- mate the burden of rotavirus gastroenteritis in children <5 years of age, to generate data to assist the policy-making process for new vaccine intro- duction and to monitor impact of vaccination on disease burden after introduction. Methods: Sentinel surveillance was conducted at 3 hospitals in Addis Ababa, Ethiopia using a standardized WHO surveillance protocol from August 2007 to March 2012. Children <5 years of age, hospitalized for the primary reason of treatment for acute gastroenteritis, were enrolled, stool samples were collected and tested for group A rotavirus using an enzyme immunoassay. Confirmed positive specimens were further characterized by rotavirus genotyping. Results: A total of 1841 children were enrolled and 21% were rotavirus positive. Children 6–12 months of age had the highest proportion of rota- virus (36%) followed by children <6 months of age (23%). There was no significant difference between sexes. Significant differences in clinical char- acteristics, such as vomiting, vomiting episodes, cases with vomiting and diarrhea among rotavirus positive cases, were observed. Rotavirus circu- lated year round with peak prevalence from October through January. The most prevalent detected genotypes were G1P[8] (20%), G12P[8] (17%) and G3P[6] (15%), respectively. Conclusions: Rotavirus infection is common in Ethiopian children. A safe and effective intervention against the infection is needed to prevent severity of the disease. Rotavirus vaccine introduction is planned before the end of 2013. The established surveillance system and the data generated can be used to monitor the impact of rotavirus vaccination program on severe disease. Key Words: rotavirus, gastroenteritis, Ethiopean children (Pediatr Infect Dis J 2014;33:S28–S33) R otavirus infection is the leading cause of severe acute gastro- enteritis in young children worldwide. Rotavirus disease is more severe than diarrhea caused by other enteric pathogens with symptoms including an average of 6 stools per day, severe dehy- dration, which is 14 times more frequent than in children without rotavirus diarrhea, vomiting and fever. 1–3 The administration of oral rehydration can be hampered by the accompanying vomiting. 4 Each year rotavirus infection leads to 453,000 rotavirus-related deaths globally with >85% of these deaths occurring in Africa and Asia. 4–8 In 2008, the World Health Organization (WHO) estimated that 28,218 deaths among children <5 years of age in Ethiopia were due to rotavirus diarrhea and rotavirus vaccines are not currently avail- able. 8 Rotavirus vaccine introduction is planned for 2013. Alhough bacterial and parasitic causes of gastroenteritis are relatively well studied, adequate information about viral etiologies of diarrhea is lacking in Ethiopia. However, some hospital-based studies in Addis Ababa and Jimma towns showed rotavirus as a major cause of nonbacterial acute gastroenteritis in infants and young children that accounted for 18–28% of acute gastroenteritis cases. 9–12 Group A rotaviruses, which account for the vast majority of human disease, are classified into different P and G-types based on the 2 outer capsid proteins, VP4 and VP7, respectively. Studies have shown wide geographical variation in G- and P-type preva- lence across continents, global temporal changes in the frequency of dominant strains and emergence of unusual P and G types and combinations. 13–18 On the basis of antigenic and genetic diversities, 27G types and 35P types have been identified to date among rotavi- rus strains of both human and animal origins. 19 In sub-Saharan Africa, although the common human rota- virus strains (G1–G4 and G9) were observed, only G1, G2 and G9 were detected routinely, and the more unusual strains (G8 and P6) were detected more frequently than in other areas of the world. 20,21 Ethiopia joined the African Rotavirus Surveillance Network in 2007 to conduct hospital-based surveillance and to estimate the burden of rotavirus gastroenteritis in children <5 years of age in 3 hospitals in Addis Ababa, Ethiopia. The evidence generated from the surveillance will assist policy makers to evaluate the need for rotavirus vaccination program for the country and to monitor the impact of vaccination following introduction. The objective of this paper is to describe the epidemiology and strain diversity of rotavi- rus in Ethiopia before vaccine introduction. METHODS Recruitment and Case Definitions Rotavirus surveillance was started in August 2007 in Black Lion hospital and expanded to 2 more hospitals, Yekatit 12 in January 2008 and BeteZata in October 2011 in Addis Ababa, Ethiopia. Inclusion and exclusion criteria for diarrhea cases were applied as specified in the Regional Office for Africa standard operating procedures and WHO Generic Protocol. 22 Children <5 years of age who were hospitalized for the primary reason of treatment for acute gastroenteritis were eligible for inclusion. Hospitalization was generally defined as admission to a hospital ward; however, when a hospital bed was not available, children rehydrated in the emergency department (for at least 6 hours under observation) were also eligible. Exclusion criteria included bloody diarrhea, symptoms lasting 7 days before presentation to Copyright © 2013 by Lippincott Williams & Wilkins ISSN: 0891-3668/14/3301-0S28 DOI: 10.1097/INF.0000000000000048 Hospital-based Surveillance for Rotavirus Gastroenteritis in  Children Younger Than 5 Years of Age in Ethiopia: 2007–2012 Almaz Abebe, PhD,* Telahun Teka, MD,† Tassew Kassa, BSc,* Mapaseka Seheri, PhD,‡ Berhane Beyene, MSc,* Birke Teshome,* Ferehiwot Kebede, MD,§ Abebe Habtamu, MD,¶ Lorens Maake, MSc,‡ Aron Kassahun, MSc,‖ Mekonnen Getahun, BSc,* Kassahun Mitiku, MD,‖ and Jason M. Mwenda, MD** Accepted for publication, August 28, 2013. From the *Ethiopian Health and Nutrition Research Institute; †Yekatit 12 Hos- pital, AAU Medical Faculty, Addis Ababa, Ethiopia; ‡MRC/UL Diarrhoeal Pathogens Research Unit, Department of Virology, Medunsa Campus, Uni- versity of Limpopo/National Health Laboratory Service, Pretoria, South Africa; §BeteZata Hospital; ¶Black Lion Hospital, AAU Medical Faculty; ‖WHO Country Office, Addis Ababa, Ethiopia; and **WHO Regional Office for Africa (WHO/AFRO), Brazzaville, The Republic of Congo. The authors have no conflicts of interest to disclose. Address for correspondence: Almaz Abebe, PhD, Ethiopian Health and Nutrition Research Institute, Arbegnoche Street, PO Box 1242, Addis Ababa, Ethiopia. E-mail: almaz_abe1@yahoo.com.