An epizootic of Rift Valley fever in Egypt in 1997

Abstract

An epizootic of Rift Valley fever (RVF) occurred in Egypt between April and August 1997. The signs among infected cattle and sheep were high fever, icterus, bloody diarrhoea and abortion. Aborted sheep foetuses and sera from the affected herds were collected in the Aswan and Assiut Provinces, Upper Egypt, for virological and serological examination. A cytopathic effect was detected in Vero cell cultures 48 h after inoculation with the foetal liver and spleen suspensions. The same suspensions caused paralysis and mortalities two to three days post intracerebral injection in mice. The isolated virus was identified using an agar gel precipitation test (AGPT) and a direct fluorescent antibody technique. Serological examination revealed that all tested sheep (57) and cattle (93) gave positive results to serological tests, using a complement fixation (CF), serum neutralisation (SN) and indirect immunofluorescence assay; while only 48 (84.2%) out of 57 sheep sera and 69 (74.2%) out of 93 cattle sera gave positive results using an AGPT. Titration of the serum samples indicated that SN is more sensitive than CF. Importation of infected ruminants, especially camels from the Sudan, is the principal source of infection. Aswan, the nearest Egyptian province to the Sudan, is the focus of RVF virus infection in Egypt. As a result of high insect populations, the epizootics of RVF have usually occurred during the summer in Egypt. Reoccurrence of epizootics from time to time indicates failure of the applied RVF vaccination programme in Egypt.

Rapid detection of important human pathogenic Phleboviruses

“…Symptoms of human infections range from mild fever to encephalitis, retinitis and fatal hepatitis with haemorrhages. RVFV was confined to SubSaharan Africa since its discovery in the 1930s, until it was detected on the Arabian peninsula in 2000 (Abd el- Rahim et al, 1999;Arthur et al, 1993;Imam and Darwish, 1977;Jouan et al, 1990;Thiongane et al, 1996;Thonnon et al, 1999). Several diagnostic PCRs for RVFV detection have been published (Drosten et al, 2002;Garcia et al, 2001;Sall et al, 2001).…”

Nuclear Relocalization of Polyadenylate Binding Protein during Rift Valley Fever Virus Infection Involves Expression of the NSs Gene

“…RVFV primarily affects livestock, causing acute fever and spontaneous abortion in 80 to 100% of pregnant animals (2,3). High rates of mortality are observed in animal infections, with the highest mortality in young animals (4,5). Humans may become infected with RVFV from bites of infected mosquitoes or contact with infected animal tissues.…”

Evidence for Arbovirus Dissemination Conduits from the Mosquito (Diptera: Culicidae) Midgut

“…RVF virus has a tripartite, singlestranded RNA genome and ranges in diameter from 90 to 120 nm (Meegan and Bailey 1988). Rift valley fever is enzootic and sporadically epidemic in sub-Saharan Africa, but since the late 1970s, several epidemics have occurred north of the Sahara, posing a serious health threat to humans and livestock (Meegan 1979, Meegan et al 1980, Abd el-Rahim et al 1999, Ahmad 2000.…”