Recurrence of Rift Valley fever in Egypt

Arthur, Ray R.; Cope, Stanton E.; Botros, B. A. M.; Hibbs, Richard G.; Imam, I. Z. E.; El-Sharkawy, M.S.; Oun, S.; Morrill, John C.; Shope, Robert E.; Darwish, Mahmoud

doi:10.1016/0140-6736(93)92128-g

Cited by 91 publications

(53 citation statements)

References 2 publications

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“…Comparable situations were also observed with the 1993 RVF virus circulation in Senegal, Mauritania and Egypt 3,8,9 and with the recent outbreak in Kenya and Somalia in 1997-1998. 10 At least two hypotheses could explain this widespread RVF virus circulation.…”

mentioning

confidence: 72%

First isolation of the Rift Valley fever virus from Culex poicilipes (Diptera: Culicidae) in nature.

Diallo¹,

Lochouarn²,

Bâ³

et al. 2000

The American Journal of Tropical Medicine and Hygiene

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Abstract. Following the reemergence of Rift Valley fever (RVF) virus in southeastern Mauritania in 1998, an entomological survey was undertaken in the boundary area in Senegal to assess the extent of the virus circulation. During this study, RVF virus (36 strains) was isolated for the first time from Culex poicilipes in nature. The possible role of Cx. poicilipes as an RVF vector is discussed regarding its biology and ecology. Rift Valley fever (RVF) is an African viral zoonosis transmitted by mosquitoes. In September and October 1998, hemorrhagic fever cases were reported in the Ayoun El Atrouss zone, Mauritania (Nabeth P, unpublished data). Rift Valley fever virus was diagnosed using IgM capture, reverse transcriptase-polymerase chain reaction (RT-PCR), and virus isolation at the Pasteur Institute, Dakar, Senegal. Following the confirmation of these RVF cases in Mauritania, entomological survey was carried out in Senegal along the river basin in Thille Boubacar, Kanel, Dembankane, and Diawara ( Figure 1) in order to evaluate the extent of virus circulation. These localities are approximately 400 kilometers from the Mauritanian epidemic/epizootic zone.Mosquitoes were collected using the Centers for Disease Control and Prevention (CDC) light traps with CO 2 set nearby temporary ground pools and CDC light traps without CO 2 set in sheepfolds or cowsheds. They were then sorted and classified into monospecific pools and stored in liquid nitrogen before virological isolation attempts were made. Isolations were performed on Vero and AP 61 (Aedes pseudoscutellaris) cell lines. Rift Valley fever virus identification was made by indirect immunofluorescence, 1 then confirmed by complement fixation and seroneutralization tests.In total, 31,944 mosquitoes belonging to 6 genera and 20 species were captured. Culex poicilipes and Mansonia uniformis were the most common species (Table 1). Thirty-six RVF virus strains were isolated from Cx. poicilipes captured in Diawara, the locality in which the highest density of Cx. poicilipes was obtained (Figure 2). The true infection rate was estimated to be 0.37 Ϯ 0.06% in Diawara.To our knowledge, this is the first isolation of RVF virus from Cx. poicilipes in nature. Among mosquitoes collected, Culex antennatus, Anopheles pharoensis, Mansonia africana and Ma. uniformis were already found naturally infected by the RVF virus. 2 Previously, RVF virus isolations were obtained in Senegal from mosquitoes Aedes dalzieli, Aedes vexans, and Aedes ochraceus. 3 Like most RVF virus vectors, Cx. poicilipes is a temporary-ground-pools mosquito well adapted to the Sahelian area. In Barkedji area where an entomological survey has been conducted since 1990, Cx. poicilipes is the most represented species after Ae. vexans. 3 In this area, a high tropism of Cx. poicilipes was observed for

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confidence: 72%

First isolation of the Rift Valley fever virus from Culex poicilipes (Diptera: Culicidae) in nature.

Diallo¹,

Lochouarn²,

Bâ³

et al. 2000

The American Journal of Tropical Medicine and Hygiene

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“…Since the epidemic in Egypt in 1977, RVF virus has been shown to infect humans extensively, leading to several disease manifestations including acute febrile illness, hepatitis, encephalitis, haemorrhagic fever and ocular sequelae (Laughlin et al, 1979). Recent RVF epidemics in Mauritania (Digoutte & Peters, 1989), Madagascar (Morvan et al, 1992) and Egypt (Arthur et al, 1993), as well as the enzootic maintenance of the virus in Senegal (Zeller et al, 1997), have emphasized the emergence of this virus as a major public health threat in Africa. With the exception of Egypt, RVF virus is confined to sub-Saharan Africa, where it is widespread and maintained in endemic\ enzootic and epizootic forms (Meegan & Bailey, 1989).…”

Section: Introductionmentioning

confidence: 99%

Variability of the NS(S) protein among Rift Valley fever virus isolates.

Sall

Zanotto

Zeller

et al. 1997

Journal of General Virology

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Eighteen strains of Rift Valley fever (RVF) virus collected over a period of 38 years and isolated from diverse localities in Africa and from various hosts (human, animal and arthropod) were investigated by RT-PCR followed by sequencing of the NS S protein coding region. This region was chosen to analyse variability because, in contrast to the N protein, the NS S protein differs in various phleboviruses and there exists an RVF virus (clone 13) in which 70 % of the NS S ORF is deleted, suggesting that this sequence is under a weak selective pressure. Sequence data indicated that percentage di-

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“…13,14 Published reports also document that buffalo experience significant morbidity (fetal loss) from wild-type RVFV infections, and RVFV has been isolated from a water buffalo ( Bubalus bubalis ) fetus. 14,15 The objectives of this study were to identify whether lowlevel RVFV transmission is ongoing in African Buffalo ( Syncerus caffer caffer ) in Kruger National Park, South Africa, to examine the variation in buffalo RVFV seroprevalence over time, and to re-examine the potential contribution of infected buffalo to local RVFV transmission during and in between periods of known epizootics.…”

Section: Introductionmentioning

confidence: 99%

Rift Valley Fever Virus Infection in African Buffalo (Syncerus caffer) Herds in Rural South Africa: Evidence of Interepidemic Transmission

LaBeaud¹,

Cross

Getz

et al. 2011

The American Society of Tropical Medicine and Hygiene

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Abstract. Rift Valley fever virus (RVFV) is an emerging biodefense pathogen that poses significant threats to human and livestock health. To date, the interepidemic reservoirs of RVFV are not well defined. In a longitudinal survey of infectious diseases among African buffalo during [2000][2001][2002][2003][2004][2005][2006], 550 buffalo were tested for antibodies against RVFV in 820 capture events in 302 georeferenced locations in Kruger National Park, South Africa. Overall, 115 buffalo (21%) were seropositive. Seroprevalence of RVFV was highest (32%) in the first study year, and decreased progressively in subsequent years, but had no detectable impact on survival. Nine (7%) of 126 resampled, initially seronegative animals seroconverted during periods outside any reported regional RVFV outbreaks. Seroconversions for RVFV were detected in significant temporal clusters during 2001-2003 and in 2004. These findings highlight the potential importance of wildlife as reservoirs for RVFV and interepidemic RVFV transmission in perpetuating regional RVFV transmission risk. Sabie (2003Sabie ( -2006 regions of the park ( Figure 1 ). Briefly, from a defined sub-region of Kruger National Park having a buffalo population of approximately 3,000, 593 buffalo were captured at 302 georeferenced locations by using aerial or ground darting techniques, working in close collaboration with veterinarians in Kruger National Park.Captured animals were tested for exposure to infections and uniquely branded and given subcutaneous insertion of microchip tags for later identification. A subset (n = 167) were fitted with either radio collars or global positioning system collars for tracking and weekly to monthly follow-up. Because male and female buffalo have horns, it was impossible for a radio collar to come off an animal without tearing through the belting. We identified mortality events by the belting still being intact and the remains of a carcass. We assumed that a radio collar had fallen off if the belting was severed and no carcass was present after an extensive search of the area. 18 We estimated time since death (0-30 days) using the extent of carcass remains.18 During the study, there were 288 live repeat captures among the 593 buffalo studied and 55 documented deaths among the 167 tracked animals.Ethical approval. Institutional Animal Care and Use Committee approval was through University of California Berkeley #R217-0402 to Wayne M. Getz. This protocol was also reviewed and approved by the Animal Care and Use Committee for the South Africa National Parks.Animal assessment. Animals < 5 years of age were assigned to an age group on the basis of physical examination for incisor eruption pattern.19 Age of animals ≥ 5 years of age at the time of first examination was determined by visual comparison of horn development and body size to a calibrated photographic reference collection. 17,20 Four age groups were considered: youngest = 1-3 years, mid-low = 3-5 years, mid-high = 5-8 years, highest = more than 8 years.Testing for antibodies ...

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Recurrence of Rift Valley fever in Egypt

Cited by 91 publications

References 2 publications

First isolation of the Rift Valley fever virus from Culex poicilipes (Diptera: Culicidae) in nature.

First isolation of the Rift Valley fever virus from Culex poicilipes (Diptera: Culicidae) in nature.

Variability of the NS(S) protein among Rift Valley fever virus isolates.

Rift Valley Fever Virus Infection in African Buffalo (Syncerus caffer) Herds in Rural South Africa: Evidence of Interepidemic Transmission

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