Hospital-Based Surveillance for Infectious Etiologies Among Patients with Acute Febrile Illness in Georgia, 2008-2011.

Information on the infectious causes of undifferentiated acute febrile illness (AFI) in Georgia is essential for effective treatment and prevention. In May 2008, a hospital-based AFI surveillance was initiated at six hospitals in Georgia. Patients aged ≥ 4 years with fever ≥ 38°C for ≥ 48 hours were eligible for surveillance. Blood culture and serologic testing were conducted for Leptospira spp., Brucella spp., West Nile virus (WNV), Crimean-Congo hemorrhagic fever virus, Coxiella burnetii, tick-borne encephalitis virus (TBEV), hantavirus, Salmonella enterica serovar Typhi (S. Typhi), and Rickettsia typhi. Of 537 subjects enrolled, 70% were outpatients, 54% were males, and the mean age was 37 years. Patients reported having fatigue (89%), rigors (87%), sweating (83%), pain in joints (49%), and sleep disturbances (42%). Thirty-nine (7%) patients were seropositive for R. typhi, 37 (7%) for Brucella spp., 36 (7%) for TBEV, 12 (2%) for Leptospira spp., 10 (2%) for C. burnetii, and three (0.6%) for S. Typhi. None of the febrile patients tested positive for WNV antibodies. Of the patients, 73% were negative for all pathogens. Our results indicate that most of the targeted pathogens are present in Georgia, and highlight the importance of enhancing laboratory capacity for these infectious diseases.

Evaluation of a newly developed ELISA against Widal, TUBEX-TF and Typhidot for typhoid fever surveillance.

INTRODUCTION: Typhoid fever is endemic in many parts of the world and represents a major cause of acute febrile illness (AFI). Rapid and accurate laboratory methods for diagnosis of this disease are needed for both patient care and surveillance situations. METHODOLOGY: Serum samples were collected from AFI patients and used to evaluate the performance of a newly developed ELISA assay that uses a mixture of somatic and flagellar antigens to detect the total antibody response against Salmonella enterica subspecies enterica serovar Typhi (S. Typhi) infection. The levels of Ig isotype response (IgG, IgM and IgA) were also evaluated, and results were compared to those of TUBEX-TF and Typhidot commercial kits.  RESULTS: Of 234 culture-confirmed typhoid patients, the total Ig ELISA diagnosed 93% compared to 71% using Widal test. This sensitivity level (93%) is higher than that observed for the individual Ig ELISAs (IgG 75%; IgM 79%; IgA 57%) and the commercial tests TUBEX-TF (75%), Typhidot IgM (63%) and Typhidot IgG (28%). An agreement of 78% was achieved between the total Ig ELISA and Widal test. The average specificity of the ELISA was 96%. Using ELISA, up to 200 samples can be tested per run with cost per test at US$0.20. CONCLUSIONS: The developed ELISA shows superior sensitivity and specificity, when compared to Widal, TUBEX-TF and Typhidot assays, is more cost effective and allows higher throughput. This method is highly recommended for active surveillance studies or outbreak investigations of typhoid fever.