Malaria Epidemic Forecasting and Preparedness Manual

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• Rainfall amounts estimated from satellite photographs andmade available on the internet by the Africa DataDissemination Service. Recently, maps especially formalaria early warning have been provided. A new map isshown every 10 days showing the differences above andbelow expected levels of rainfall• Entomological data on numbers of adult or larvalmosquitoes caught in routine standardized catches atsentinel sites. We do not yet know what suitable thresholdnumbers of mosquitoes would be. Therefore we do notknow yet whether this entomological data will be useful,but it may be in the future.To use meteorological data for warning, we need to havedetailed knowledge of past rainfall levels and define what is anabnormal (unusual) amount for a particular location. Thus, wehave to have an estimate of “normal” rainfall. Fig. 4 shows theaverage rainfall by month (thick solid line) over the period1990–2000 at one rainfall station (Elabered). It also shows 1.5and 2 times the average monthly rainfall (dotted line and thinsold line respectively), as well as the actual rainfall in the years1996 to 2000 (bars).Rainfall (mm)400350300250200150100500Jan-96Apr-96Fig 4: Rainfall, Elabered 1996 - 2000Actual Rainfall Average 1990-2000 1.5xAverage 2x AverageJul-96Oct-96Jan-97Apr-97Jul-97Oct-97Jan-98Apr-98Jul-98MonthOct-98Jan-99Apr-99Jul-99Oct-99Jan-00Apr-00Jul-00Oct-00Eritrea Epidemic Manual, June 2003 13
You can see from Fig. 4 that there was abnormally high rainfallearly in the season in 1996: more than twice the average for themonth of April 1996. The monthly totals for the rest of the year1996 were fairly normal.In 1997 we had unusually high early rainfall in May, and therain also continued unusually late that year. The amounts inMay, October and November 1997 were more than twice theaverages for those months.Note that 1997 was an El Niño year. Long-term seasonalforecasts are most likely to be accurate in such years.In 1998, there was again abnormal early rainfall (in May 98),and much more rain than usual in August 1998. Rainfall was atleast twice the average in each of these months.To use monthly rainfall data for early warning, each month’saverage rain needs to be summarized as quickly as possible afterthe end of the month, and compared with the 10-year average.Fig.5: ElaberedRainfall and Malaria OPD Cases 1996-2000Actual RainfallMalaria OPD Cases400400350350Malaria OPD Cases300250200150100300250200150100Rainfall (mm)505000JFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASOND1996 1997 1998 1999 2000Month14Eritrea Epidemic Manual, June 2003
Page 2: Malaria Epidemic Forecastingand Pre
Page 6: ContentsIntroduction...............
Page 9 and 10: There are also criteria for decidin
Page 12: 1. General Definitionof an Epidemic
Page 15 and 16: Fig 1: GASH BARKA - GULUJ 1996 - 20
Page 18: 3. GeographicStratificationStratifi
Page 21 and 22: If there has been unusually large m
Page 23: Long-term forecasting (severalmonth
Page 27 and 28: 6. Inform Epidemic Preparedness and
Page 29 and 30: The threshold can be calculated by
Page 31 and 32: To calculate and draw monthly thres
Page 33 and 34: Table 2:MonthRe-ordered OPD malaria
Page 35 and 36: To calculate and draw weekly thresh
Page 37 and 38: Definition of an epidemicAt the beg
Page 39 and 40: 2. Drugs3. Insecticides for IRS and
Page 41 and 42: factor (for example increase in num
Page 43 and 44: ResponseWhen to change from “ALER
Page 45 and 46: Table 2:MonthJanFebMarAprMayJunJuly
Page 47 and 48: Graphs are shown in the sheets call
Page 49 and 50: Month GraphEXAMPLE Health Centre400
Page 51 and 52: Week Data continuedweek median 3rd

Malaria Epidemic Forecasting and Preparedness Manual

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