Epidemiological Analysis of Malaria Outbreak in Ankesha District, Awi Zone, Amhara Region, Ethiopia, 2012: Weaknesses in Control Measures and Risk Factors

While malaria is mostly an endemic disease in Ethiopia. It may also occur as outbreaks in areas with low seasonal transmission because of an increase in vector breeding sites, migration of infected people into a vector-rich area populated with susceptible individuals, breakdown of vector control measures and resistance of the vectors to insecticides. The aim of this study was to verify, investigate the outbreak epidemiologically and guide intervention measures. We reviewed data from health post records from 2007 to 2011 and screened randomly 50 fevers cases from the community members by Rapid Diagnostic Test/RDT/ to determine the baseline incidence of malaria in Ankesha District. We defined a confirmed malaria cases as any person with fever or fever with headache with plasmodium parasites by confirmed microscopy and RDT. We conduct descriptive epidemiological study and Entomological survey. A total of 2,061 confirmed malaria cases and one death (CFR=0.05%) were identified. Among the species distributions, plasmodium falciparum was accounted 1484 (72%). The alert threshold (Quartile for 5th year’s data/doubling the last year data) had been reached and crossed in 24th March, 2012 in all health facilities. It showed highest peak between the epidemiological weeks of 17-27 in 2012. The median age was 17 years with a range 0.2 to 83 years. The highest age specific attack rate was in 5-14yr, 17.9 per1000 (642) population. Among sex distribution male comprise 53.3%. The attack rate was high in Azena Kebele which was 165per 1000(883) population in under-fives and 132 per 1000(745) population in>5 years old. Environmental assessment revealed the presence of multiple breeding sits, which was favorable for larvae of Anopheles mosquito. Arbitrarily 53 visited households were observed the LLIN bed net utilization, only 17 (32.1%) households were hanging in their ceiling directly to the bedding. And also IRS was not sprayed for last one years in all affected kebeles. The outbreak was caused by the breakage of Ayehu river formed high larva density, improper usage of LLIN’s bed net and impediment / low coverage of IRS operation. Factors such as delayed detection and notification and inadequate surveillance were also instrumental for the outbreak. We recommended creates awareness giving health education, strengthen the surveillance system and implement a community based program on the LLINs utilization, IRS and environmental management.