[Role of laboratory methods in epidemic control of brucellosis outbreaks in Moscow zoo nursery]

Evaluation of the role of contemporary methods in epidemic control of brucellosis outbreaks among employees of auxiliary facilities in Moscow zoo nursery.

During 2003-2013, biannually, sera from more than 200 employees of the nursery, that work during periods of epizootics of small and large cattle in nursery auxiliary facilities, were studied. A complex of laboratory methods for brucellosis was used: variations of traditional serologic agglutination method in tubes--Wright's reaction (WR), on glass--Huddleston's reaction, Coombs' anti-globulin reaction; enzyme immunoassay with immune-dominant S-LPS; realtime polymerase chain reaction with primers based on genus target of BCSP31 protein gene.

After eradication of sheep brucellosis in 2003, the percentage of nursery facility employees, that react positively to brucellosis, has decreased from 42.7% to 15.9-17.2% in 2005-2006. RT-PCR detected human infection during epizootics 5.8 times more effectively compared with EIA. The repetition of the brucellosis epizootics in 2007 and 2009 among large cattle and a 2-year yak had initiated a rise in infection rate among employees, that had not previously (2003-2006) reacted to brucellosis. Acute clinical forms of brucellosis were not detected in 2012-2013 and antibody titers in EIA in previously infected employees have decreased in the absence ofbrucellosis epizootics in the nursery. 30 employees, infected with brucellosis causative agent, were detected for the entire period of examination, among those 10 individuals had developed clinical forms of brucellosis (6--acute, 4--chronic).

Epidemic control for 11 years, based on a complex of laboratory methods, allowed to register infection and outbreaks of brucellosis in the nursery employees during epizootics of 2003, 2007 and 2009. RT-PCR--effective method of detection of infection in humans during brucellosis periods in the nursery. EIA--sensitive method during chronic forms of brucellosis in the periods between and after epizootics compared with RT-PCR. A variation of a traditional serologic method of diagnostics has shown a lower sensitivity, informativity with a larger duration of analysis compared with RT-PCR and EIA.