Technical Guidelines for Integrated Disease Surveillance ... - PHRplus

If the shape of the curve suddenly increases to develop a steep up-slope, and then descends just asrapidly, exposure to the causal agent was probably over a brief period of time. There may be a commonsource of infection.If exposure to the common source was over a long period of time, the shape of the epidemic curveis more likely to be a plateau rather than a sharp peak.If the illness resulted from person-to-person transmission, the curve will present as a series ofprogressively taller peaks separated by periods of incubation.4.10.2 Interpret the place analysis resultsUse the map to:Describe the geographic extent of the problem.Identify and describe any clusters or patterns of transmission or exposure. Depending on the organismthat has contributed to this outbreak, specify the proximity of the cases to likely sources of infection.4.10.3 Interpret the person analysis resultsInformation developed from the person analysis is essential for planning the outbreak response because itdescribes more precisely the population at risk for transmission of this disease or condition. For example, ifyellow fever cases occurred in patients less than 15 years of age, then the immunization response action wouldneed to target children less than 15 years of age.For measles, if the proportion of cases in children younger than 5 years is high and immunization coverageis low, then there is a problem with immunization. If the coverage is high then the cold chain system will need tobe reviewed.4.10.4 Calculate case fatality ratesRefer to the steps in Section 3 that describe how to calculate case fatality rates.52Technical Guidelines for Integrated Disease Surveillance and Response in Ghana