Comparative study on serodiagnostic techniques of Brucella infection in Egypt

Abstract

Background: Brucellosis is a zoonotic disease that affects wild and domestic animals causing a decrease in reproductive efficiency and abortion and can be transmitted to human. The incidence of human disease is closely tied to the prevalence of infection in animals and considered as an important health problem in Egypt.

Methods and Findings: In this study, blood specimens from 68 patients that showed clinical signs and/or history of brucellosis and from different investigated animals (76 buffalo, 145 cattle and 191 sheep) were collected and serodiagnosed for Brucella infection. The sera of these blood specimens were first screened by rose bengal plate test (RBPT) and those giving positive reaction were retested by the standard tube agglutination test (SAT), EDTA modified SAT and rivanol test to determine their titers. The results for clinical specimens showed that 89.70%, 82.35%, 66.18% and 58.82% were positive using RBPT, SAT, EDTA modified SAT and rivanol test, respectively. The respective percentages of brucellosis in buffalo were 44.70%, 43.42%, 43.42% and 43.24%; while the respective percentages of brucellosis in cattle were 46.90%, 43.45%, 39.31% and 37.93%. In addition, serological examination of 191 sheep revealed that 60.20%, 56.54%, 53.40% and 51.83% were positive using RBPT, SAT, EDTA modified SAT and rivanol test, respectively.

Conclusion: The results give clear evidence for: (i) the real picture of brucellosis surveillance among human cannot be reflected using single serodiagnostic test, (ii) In comparison to human, serodiagnosis of Brucella among animals is less dependent on test type and such dependency took the order sheep > cattle > buffalo, (iii) serodiagnosis of Brucella among buffalo had nearly no dependency on test type.