Enzootic hepatitis or rift valley fever. An undescribed virus disease of sheep cattle and man from east africa

1931 ◽  
Vol 34 (4) ◽  
pp. 545-579 ◽  
Author(s):  
R. Daubney ◽  
J. R. Hudson ◽  
P. C. Garnham
Keyword(s):  
East Africa ◽  
Rift Valley ◽  
Rift Valley Fever ◽  
Virus Disease ◽  
Valley Fever

scholarly journals Development and Assessment of Localized Seasonal Rainfall Prediction Models: Mapping and Characterizing Rift Valley Fever Hotspot Areas in the Southern and Southeastern Ethiopia

2018 ◽  
Vol 11 (5) ◽  
pp. 102
Author(s):  
Ephrem Weledekidane
Keyword(s):  
East Africa ◽  
Rift Valley ◽  
Rift Valley Fever ◽  
Large Scale ◽  
Prediction Models ◽  
Rainfall Anomaly ◽  
Seasonal Rainfall ◽  
Valley Fever ◽  
Average Rainfall ◽  
Early Indicators

Rift Valley Fever disease has been recognized as being among permanent threats for the sustainability of livestock production in Ethiopia, owing to shared boarders with RVF endemic countries in East Africa. Above-normal and widespread rainfall have outweighed as immediate risk factor that facilitated historical outbreaks of the disease in the East Africa. The objective of the present study, thus, was to develop prospective localized seasonal rainfall anomaly prediction models, and assess their skills as early indicators to map high risk localized rift valley fever disease outbreak areas (hotspots) over the southern and southeastern part of Ethiopia. 21 years of daily rainfall data; for five meteorological stations, was employed in diagnosing existences of any anomalous patterns of rainfall, along with a cumulative rainfall analysis to determine if there were ideal conditions for potential flooding. The results indicated that rainfall in the region is highly variable; with non-significant trends, and attributed to be the results of the effects of large-scale climatic-teleconnection. The moderate to strong positive correlations found between the regional average rainfall and large scale teleconnection variables (r ≥ 0.48), indicated some potentials for early prediction of seasonal patterns of rainfall. Accordingly, models developed, based on the regional average rainfall and emerging developments of El Niño/Southern Oscillation and other regional climate forcings, showed maximum skills (ROC scores ≥ 0.7) and moderate reliability. Deterministically, most of the positive rainfall anomaly patterns, corresponding to El Niño years, were portrayed with some skills. The study demonstrated that localized climate prediction models are invaluable as early indicators to skillfully map climatically potential RVF hotspot areas.

Rift Valley fever virus activity in East Africa in 1989

1992 ◽  
Vol 130 (12) ◽  
pp. 247-249 ◽  
Author(s):  
F. Davies ◽  
T. Logan ◽  
Y. Binepal ◽  
P. Jessen
Keyword(s):  
East Africa ◽  
Rift Valley ◽  
Rift Valley Fever ◽  
Rift Valley Fever Virus ◽  
Fever Virus ◽  
Valley Fever ◽  
Virus Activity

scholarly journals Genetic Reassortment of Rift Valley Fever Virus in Nature

1999 ◽  
Vol 73 (10) ◽  
pp. 8196-8200 ◽  
Author(s):  
A. A. Sall ◽  
P. M. de A. Zanotto ◽  
O. K. Sene ◽  
H. G. Zeller ◽  
J. P. Digoutte ◽  
...  
Keyword(s):  
East Africa ◽  
Rift Valley ◽  
Rift Valley Fever ◽  
Rift Valley Fever Virus ◽  
Statistical Tests ◽  
Direct Sequencing ◽  
Fever Virus ◽  
Human Populations ◽  
Sylvatic Cycle ◽  
Valley Fever

ABSTRACT Rift Valley fever virus (RVFV), a phlebovirus of theBunyaviridae family, is an arthropod-borne virus which emerges periodically throughout Africa, emphasizing that it poses a major threat for animal and human populations. To assess the genetic variability of RVFV, several isolates from diverse localities of Africa were investigated by means of reverse transcription-PCR followed by direct sequencing of a region of the small (S), medium (M), and large (L) genomic segments. Phylogenetic analysis showed the existence of three major lineages corresponding to geographic variants from West Africa, Egypt, and Central-East Africa. However, incongruences detected between the L, M, and S phylogenies suggested that genetic exchange via reassortment occurred between strains from different lineages. This hypothesis, depicted by parallel phylogenies, was further confirmed by statistical tests. Our findings, which strongly suggest exchanges between strains from areas of endemicity in West and East Africa, strengthen the potential existence of a sylvatic cycle in the tropical rain forest. This also emphasizes the risk of generating uncontrolled chimeric viruses by using live attenuated vaccines in areas of endemicity.

scholarly journals Climate-disease connections: Rift Valley Fever in Kenya

2001 ◽  
Vol 17 (suppl) ◽  
pp. S133-S140 ◽  
Author(s):  
Assaf Anyamba ◽  
Kenneth J. Linthicum ◽  
Compton J. Tucker
Keyword(s):  
East Africa ◽  
Rift Valley ◽  
Rift Valley Fever ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Southern Oscillation ◽  
Close Association ◽  
Enso Event ◽  
Infected Mosquito ◽  
Valley Fever

All known Rift Valley fever(RVF) outbreaks in Kenya from 1950 to 1998 followed periods of abnormally high rainfall. On an interannual scale, periods of above normal rainfall in East Africa are associated with the warm phase of the El Niño/Southern Oscillation (ENSO) phenomenon. Anomalous rainfall floods mosquito-breeding habitats called dambos, which contain transovarially infected mosquito eggs. The eggs hatch Aedes mosquitoes that transmit the RVF virus preferentially to livestock and to humans as well. Analysis of historical data on RVF outbreaks and indicators of ENSO (including Pacific and Indian Ocean sea surface temperatures and the Southern Oscillation Index) indicates that more than three quarters of the RVF outbreaks have occurred during warm ENSO event periods. Mapping of ecological conditions using satellite normalized difference vegetation index (NDVI) data show that areas where outbreaks have occurred during the satellite recording period (1981-1998) show anomalous positive departures in vegetation greenness, an indicator of above-normal precipitation. This is particularly observed in arid areas of East Africa, which are predominantly impacted by this disease. These results indicate a close association between interannual climate variability and RVF outbreaks in Kenya.

Origin of 1997–98 Rift Valley fever outbreak in East Africa

The Lancet ◽  
1998 ◽  
Vol 352 (9140) ◽  
pp. 1596-1597 ◽  
Author(s):  
M Bouloy ◽  
AA Sall ◽  
PM de A Zanotto ◽  
P Vialat ◽  
OK Sene
Keyword(s):  
East Africa ◽  
Rift Valley ◽  
Rift Valley Fever ◽  
Valley Fever

Lessons from the 2006–2007 Rift Valley fever outbreak in East Africa: implications for prevention of emerging infectious diseases

2008 ◽  
Vol 3 (5) ◽  
pp. 411-417 ◽  
Author(s):  
Robert F Breiman ◽  
M Kariuki Njenga ◽  
Sarah Cleaveland ◽  
SK Sharif ◽  
Murithi Mbabu ◽  
...  
Keyword(s):  
Infectious Diseases ◽  
East Africa ◽  
Rift Valley ◽  
Rift Valley Fever ◽  
Emerging Infectious Diseases ◽  
Valley Fever
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