scholarly journals Multiple Virus Lineages Sharing Recent Common Ancestry Were Associated with a Large Rift Valley Fever Outbreak among Livestock in Kenya during 2006-2007

2008 ◽  
Vol 82 (22) ◽  
pp. 11152-11166 ◽  
Author(s):  
Brian H. Bird ◽  
Jane W. K. Githinji ◽  
Joseph M. Macharia ◽  
Jacqueline L. Kasiiti ◽  
Rees M. Muriithi ◽  
...  
Keyword(s):  
Rift Valley ◽  
Rift Valley Fever ◽  
Gene Segment ◽  
Genomic Diversity ◽  
Common Ancestry ◽  
Outbreak Response ◽  
Valley Fever ◽  
Virus Activity ◽  
Epidemic Period ◽  
Multiple Virus

ABSTRACT Rift Valley fever (RVF) virus historically has caused widespread and extensive outbreaks of severe human and livestock disease throughout Africa, Madagascar, and the Arabian Peninsula. Following unusually heavy rainfall during the late autumn of 2006, reports of human and animal illness consistent with RVF virus infection emerged across semiarid regions of the Garissa District of northeastern Kenya and southern Somalia. Following initial RVF virus laboratory confirmation, a high-throughput RVF diagnostic facility was established at the Kenyan Central Veterinary Laboratories in Kabete, Kenya, to support the real-time identification of infected livestock and to facilitate outbreak response and control activities. A total of 3,250 specimens from a variety of animal species, including domesticated livestock (cattle, sheep, goats, and camels) and wildlife collected from a total of 55 of 71 Kenyan administrative districts, were tested by molecular and serologic assays. Evidence of RVF infection was found in 9.2% of animals tested and across 23 districts of Kenya, reflecting the large number of affected livestock and the geographic extent of the outbreak. The complete S, M, and/or L genome segment sequence was obtained from a total of 31 RVF virus specimens spanning the entire known outbreak period (December-May) and geographic areas affected by RVF virus activity. Extensive genomic analyses demonstrated the concurrent circulation of multiple virus lineages, gene segment reassortment, and the common ancestry of the 2006/2007 outbreak viruses with those from the 1997-1998 east African RVF outbreak. Evidence of recent increases in genomic diversity and effective population size 2 to 4 years prior to the 2006-2007 outbreak also was found, indicating ongoing RVF virus activity and evolution during the interepizootic/epidemic period. These findings have implications for further studies of basic RVF virus ecology and the design of future surveillance/diagnostic activities, and they highlight the critical need for safe and effective vaccines and antiviral compounds to combat this significant veterinary and public health threat.

scholarly journals Distribution and Molecular Identification of Culex pipiens and Culex tritaeniorhynchus as Potential Vectors of Rift Valley Fever Virus in Jazan, Saudi Arabia

Pathogens ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1334
Author(s):  
Saleh Eifan ◽  
Atif Hanif ◽  
Islam Nour ◽  
Sultan Alqahtani ◽  
Zaki M. Eisa ◽  
...  
Keyword(s):  
Rift Valley ◽  
Culex Pipiens ◽  
Rift Valley Fever ◽  
Rift Valley Fever Virus ◽  
Gene Segment ◽  
Fever Virus ◽  
Coi Gene ◽  
Rt Pcr ◽  
Valley Fever ◽  
Culex Tritaeniorhynchus

Entomologic investigations were conducted in the Al-Darb, Al-Reath, Al-Aridah, Abuareesh, Al-Ahad, Samttah, Sabyah, Damad and Beash areas by CO2-baited CDC miniature light traps in the Jazan region. Vectors were identified morphologically, as well as COI gene segment amplification and sequencing. The relative abundance (RA%) and pattern of occurrence (C%) were recorded. The presence of the Rift Valley fever virus (RVFV) in pooled mosquito samples was investigated by reverse transcriptase-polymerase chain reaction (RT-PCR). Culex pipiens (C. pipiens) and Culex tritaeniorhynchus (C. tritaeniorhynchus) were found with RA% values of 96% and 4%, respectively, in the region. Significant variations in vector population densities were observed in different districts. The C. pipiens was found highly abundant in all districts and RA% value (100%) was recorded in the Al-Darb, Al-Reath, Al-Aridah, Samttah and Damad areas, whereas RA% values (93.75%, 93.33%, 92.30% and 91.66%) were noted in Al-Ahad, Sabyah, Abuareesh and Beash districts, respectively. RA% values for C. tritaeniorhynchus were recorded as 8.33%, 7.70%, 6.66% and 6.25% in Beash, Abuareesh, Sabyah and Al-Ahad areas, respectively. The pattern of occurrence for C. pipiens and C. tritaeniorhynchus was recorded as 100% and 44.4% in the region. Phylogenetic analysis of C. pipiens and C. tritaeniorhynchus exhibited a close relationship with mosquitoes from Kenya and Turkey, respectively. All mosquito samples tested by RT-PCR were found negative for RVFV. In summary, the current study assessed the composition, abundance, distribution of different mosquito vectors and presence of RVFV in different areas of the Jazan region. Our data will help risk assessments of RVFV future re-emergence in the region.

scholarly journals Patterns of Rift Valley fever activity in Zambia

1992 ◽  
Vol 108 (1) ◽  
pp. 185-191 ◽  
Author(s):  
F. G. Davies ◽  
E. Kilelu ◽  
K. J. Linthicum ◽  
R. G. Pegram
Keyword(s):  
Remote Sensing ◽  
Satellite Imagery ◽  
Rift Valley ◽  
Rift Valley Fever ◽  
Rift Valley Fever Virus ◽  
Serum Samples ◽  
Valley Fever ◽  
Low Level ◽  
Virus Activity ◽  
Cattle Serum

SUMMARYSummary An hypothesis that there was an annual emergence of Rift Valley fever virus in Zambia, during or after the seasonal rains, was examined with the aid of sentinel cattle. Serum samples taken during 1974 and 1978 showed evidence of epizootic Rift Valley fever in Zambia, with more than 80% positive. A sentinel herd exposed from 1982 to 1986 showed that some Rift Valley fever occurred each year. This was usually at a low level, with 3–8% of the susceptible cattle seroconverting. In 1985–6 more than 20% of the animals seroconverted, and this greater activity was associated with vegetational changes - which could be detected by remote-sensing satellite imagery-which have also been associated with greater virus activity in Kenya.

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 Seroprevalence of Rift Valley fever virus in livestock during inter-epidemic period in Egypt, 2014/15

2017 ◽  
Vol 13 (1) ◽  
Author(s):  
Claudia Mroz ◽  
Mayada Gwida ◽  
Maged El-Ashker ◽  
Mohamed El-Diasty ◽  
Mohamed El-Beskawy ◽  
...  
Keyword(s):  
Rift Valley ◽  
Rift Valley Fever ◽  
Rift Valley Fever Virus ◽  
Fever Virus ◽  
Valley Fever ◽  
Epidemic Period

scholarly journals Serological and genomic evidence of Rift Valley fever virus during inter-epidemic periods in Mauritania

2016 ◽  
Vol 145 (5) ◽  
pp. 1058-1068 ◽  
Author(s):  
M. RISSMANN ◽  
M. EIDEN ◽  
B. O. EL MAMY ◽  
K. ISSELMOU ◽  
B. DOUMBIA ◽  
...  
Keyword(s):  
Rift Valley ◽  
Rift Valley Fever ◽  
Rift Valley Fever Virus ◽  
Simultaneous Detection ◽  
Small Ruminants ◽  
Fever Virus ◽  
Serum Samples ◽  
Valley Fever ◽  
Epidemic Period ◽  
And Shifts

SUMMARYRift Valley fever virus (RVFV) is an emerging pathogen of major concern throughout Africa and the Arabian Peninsula, affecting both livestock and humans. In the past recurrent epidemics were reported in Mauritania and studies focused on the analysis of samples from affected populations during acute outbreaks. To verify characteristics and presence of RVFV during non-epidemic periods we implemented a multi-stage serological and molecular analysis. Serum samples of small ruminants, cattle and camels were obtained from Mauritania during an inter-epidemic period in 2012–2013. This paper presents a comparative analysis of potential variations and shifts of antibody presence and the capability of inter-epidemic infections in Mauritanian livestock. We observed distinct serological differences between tested species (seroprevalence: small ruminants 3·8%, cattle 15·4%, camels 32·0%). In one single bovine from Nouakchott, a recent RVF infection could be identified by the simultaneous detection of IgM antibodies and viral RNA. This study indicates the occurrence of a low-level enzootic RVFV circulation in livestock in Mauritania. Moreover, results indicate that small ruminants can preferably act as sentinels for RVF surveillance.

scholarly journals Prevalence of antibodies against Rift Valley fever virus in Kenyan wildlife

2007 ◽  
Vol 136 (9) ◽  
pp. 1261-1269 ◽  
Author(s):  
A. EVANS ◽  
F. GAKUYA ◽  
J. T. PAWESKA ◽  
M. ROSTAL ◽  
L. AKOOLO ◽  
...  
Keyword(s):  
Rift Valley ◽  
Neutralizing Antibodies ◽  
Rift Valley Fever ◽  
Rift Valley Fever Virus ◽  
Fever Virus ◽  
African Buffalo ◽  
Antibody Prevalence ◽  
Valley Fever ◽  
Wildlife Species ◽  
Epidemic Period

SUMMARYRift Valley fever virus (RVFV) is an arbovirus associated with periodic outbreaks, mostly on the African continent, of febrile disease accompanied by abortion in livestock, and a severe, fatal haemorrhagic syndrome in humans. However, the maintenance of the virus during the inter-epidemic period (IEP) when there is low or no disease activity detected in livestock or humans has not been determined. This study report prevalence of RVFV-neutralizing antibodies in sera (n=896) collected from 16 Kenyan wildlife species including at least 35% that were born during the 1999–2006 IEP. Specimens from seven species had detectable neutralizing antibodies against RVFV, including African buffalo, black rhino, lesser kudu, impala, African elephant, kongoni, and waterbuck. High RVFV antibody prevalence (>15%) was observed in black rhinos and ruminants (kudu, impala, buffalo, and waterbuck) with the highest titres (up to 1:1280) observed mostly in buffalo, including animals born during the IEP. All lions, giraffes, plains zebras, and warthogs tested were either negative or less than two animals in each species had low (⩽1:16) titres of RVFV antibodies. Of 249 sera collected from five wildlife species during the 2006–2007 outbreak, 16 out of 19 (84%) of the ruminant (gerenuk, waterbuck, and eland) specimens had RVFV-neutralizing titres ⩾1:80. These data provide evidence that wild ruminants are infected by RVFV but further studies are required to determine whether these animals play a role in the virus maintenance between outbreaks and virus amplification prior to a noticeable outbreak.

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