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EMPRES WATCH
VOL. 27 - December 2012
Rift Valley Fever
Vigilance needed in the coming months
Contributors: Carlene Trevennec,a Claudia Pittiglio,a Sherrilyn Wainwright,a Ludovic Plee,a Julio Pinto,a Juan Lubroth,a and Vincent Martin a Food and Agriculture Organization of the United Nations (FAO)
Introduction
In early September 2012, a human case of RVF was reportedin Mauritania. By 30 October 2012, a total of six regions had been affected with 34
human cases of RVF, including 17 deaths.
Only the southern regions of Mauritania, those closest to the usual enzootic areas along the Senegal River, seem to have been involved in this event. Although no active cases in animals have been reported to the World Organisation for Animal Health (OIE), analyses conducted by the National Veterinary Research Laboratory show serological evidence of ongoing virus circulation in several regions of the country, along with reports of abortions in sheep and camels.
From late July to late August 2012, above-normal precipitation (150 percent) was recorded in the sub-Saharan belt including southeastern Mauritania and adjacent areas in Mali, the middle and lower Niger River basin in Mali, the Lake Chad basin in the Niger, Chad, Nigeria and Cameroon. Flash and river floods, caused by excessive precipitation in and upstream of many locations in the Lake Chad and River Niger basin, were reported (ACMAD, 2012) (Figure 1). The current RVF event in Mauritania, which may be associated with the unusually high rainfall observed in the sub-Saharan belt this year, began just one year after OIE received the final report from Mauritania?s 2011 RVF outbreak. This 2011 outbreak was situated in the northern desert region of Adrar, a very different ecological environment from the current outbreak area.
Retrospective reviews from eastern Africa show that previous RVF epidemics have occurred in cycles of 5 to 15 years and have been linked with periods of unusually heavy rainfall associated with El Ni?o Southern Oscillation1 (ENSO) warm events. Since July 2012, after a period of neutral conditions, climate indicators are showing anomalies, which are suggestive of borderline ENSO warm events. Areas at risk of an RVF epizootic will benefit from strengthened local surveillance and
preparedness for outbreaks during the next two to six months.
Full text:
VOL. 27 - December 2012
Rift Valley Fever
Vigilance needed in the coming months
Contributors: Carlene Trevennec,a Claudia Pittiglio,a Sherrilyn Wainwright,a Ludovic Plee,a Julio Pinto,a Juan Lubroth,a and Vincent Martin a Food and Agriculture Organization of the United Nations (FAO)
Introduction
In early September 2012, a human case of RVF was reportedin Mauritania. By 30 October 2012, a total of six regions had been affected with 34
human cases of RVF, including 17 deaths.
Only the southern regions of Mauritania, those closest to the usual enzootic areas along the Senegal River, seem to have been involved in this event. Although no active cases in animals have been reported to the World Organisation for Animal Health (OIE), analyses conducted by the National Veterinary Research Laboratory show serological evidence of ongoing virus circulation in several regions of the country, along with reports of abortions in sheep and camels.
From late July to late August 2012, above-normal precipitation (150 percent) was recorded in the sub-Saharan belt including southeastern Mauritania and adjacent areas in Mali, the middle and lower Niger River basin in Mali, the Lake Chad basin in the Niger, Chad, Nigeria and Cameroon. Flash and river floods, caused by excessive precipitation in and upstream of many locations in the Lake Chad and River Niger basin, were reported (ACMAD, 2012) (Figure 1). The current RVF event in Mauritania, which may be associated with the unusually high rainfall observed in the sub-Saharan belt this year, began just one year after OIE received the final report from Mauritania?s 2011 RVF outbreak. This 2011 outbreak was situated in the northern desert region of Adrar, a very different ecological environment from the current outbreak area.
Retrospective reviews from eastern Africa show that previous RVF epidemics have occurred in cycles of 5 to 15 years and have been linked with periods of unusually heavy rainfall associated with El Ni?o Southern Oscillation1 (ENSO) warm events. Since July 2012, after a period of neutral conditions, climate indicators are showing anomalies, which are suggestive of borderline ENSO warm events. Areas at risk of an RVF epizootic will benefit from strengthened local surveillance and
preparedness for outbreaks during the next two to six months.
Full text:
