title: Seroprevalence of Rift Valley fever virus in livestock during inter-epidemic period in Egypt, 2014/15.
abstract: BACKGROUND
  Rift Valley fever virus (RVFV) caused several outbreaks throughout the African continent and the Arabian Peninsula posing significant threat to human and animal health. In Egypt the first and most important Rift Valley fever epidemic occurred during 1977/78 with a multitude of infected humans and huge economic losses in livestock. After this major outbreak, RVF epidemics re-occurred in irregular intervals between 1993 and 2003. Seroprevalence of anti-RVFV antibodies in livestock during inter-epidemic periods can be used for supporting the evaluation of the present risk exposure for animal and public health. A serosurvey was conducted during 2014/2015 in non-vaccinated livestock including camels, sheep, goats and buffalos in different areas of the Nile River Delta as well as the furthermost southeast of Egypt to investigate the presence of anti-RVFV antibodies for further evaluating of the risk exposure for animal and human health. All animals integrated in this study were born after the last Egyptian RVF epidemic in 2003 and sampled buffalos and small ruminants were not imported from other endemic countries.
  
  
  RESULTS
  A total of 873 serum samples from apparently healthy animals from different host species (camels: n = 221; sheep: n = 438; goats: n = 26; buffalo: n = 188) were tested serologically using RVFV competition ELISA, virus neutralization test and/or an indirect immunofluorescence assay, depending on available serum volume. Sera were assessed positive when virus neutralization test alone or least two assays produced consistent positive results. The overall seroprevalence was 2.29% (95%CI: 1.51-3.07) ranging from 0% in goats, 0.46% in sheep (95%CI: 0.41-0.5), and 3.17% in camels (95%CI: 0.86-5.48) up to 5.85% in buffalos (95%CI: 2.75-8.95).
  
  
  CONCLUSIONS
  Our findings assume currently low level of circulating virus in the investigated areas and suggest minor indication for a new RVF epidemic. Further the results may indicate that during long inter-epidemic periods, maintenance of the virus occur in vectors and also most probably in buffaloes within cryptic cycle where sporadic, small and local epidemics may occur. Therefore, comprehensive and well-designed surveillance activities are urgently needed to detect first evidence for transition from endemic to epidemic cycle.
authors.affiliation: Institute of Novel and Emerging Infectious Diseases, Friedrich-Loeffler-Institut, Südufer 10, 17493, Greifswald - Isle of Riems, Germany.
authors.forename: Claudia
authors.initials: C
authors.lastname: Mroz
authors.affiliation: Department of Hygiene and Zoonoses, Faculty of Veterinary Medicine, Mansoura University, Mansoura, 35516, Egypt.
authors.forename: Mayada
authors.initials: M
authors.lastname: Gwida
authors.affiliation: Department of Internal Medicine and Infectious Diseases, Faculty of Veterinary Medicine, Mansoura University, Mansoura, 35516, Egypt.
authors.forename: Maged
authors.initials: M
authors.lastname: El-Ashker
authors.affiliation: Animal Health Research Institute-Mansoura Provincial Laboratory, Mansoura, Egypt.
authors.forename: Mohamed
authors.initials: M
authors.lastname: El-Diasty
authors.affiliation: Faculty of Veterinary Medicine, Mansoura University, Mansoura, Egypt.
authors.forename: Mohamed
authors.initials: M
authors.lastname: El-Beskawy
authors.affiliation: Institute of Novel and Emerging Infectious Diseases, Friedrich-Loeffler-Institut, Südufer 10, 17493, Greifswald - Isle of Riems, Germany.
authors.forename: Ute
authors.initials: U
authors.lastname: Ziegler
authors.affiliation: Institute of Novel and Emerging Infectious Diseases, Friedrich-Loeffler-Institut, Südufer 10, 17493, Greifswald - Isle of Riems, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Eiden
authors.affiliation: Institute of Novel and Emerging Infectious Diseases, Friedrich-Loeffler-Institut, Südufer 10, 17493, Greifswald - Isle of Riems, Germany. martin.groschup@fli.bund.de.
authors.forename: Martin H
authors.initials: MH
authors.lastname: Groschup
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D002162:Camelus / Q000821:virology*; D004534:Egypt / Q000453:epidemiology; D058751:Livestock / Q000821:virology*; D012295:Rift Valley Fever / Q000097:blood / Q000453:epidemiology* / Q000276:immunology; D012296:Rift Valley fever virus / Q000276:immunology*; D012418:Ruminants / Q000821:virology*; D016036:Seroepidemiologic Studies
chemical_list: D000914:Antibodies, Viral
keywords: Egypt; Inter-epidemic period; Livestock; Rift Valley fever virus; Surveillance