Development of an Improved Rapid Lateral Flow Assay for the Detection of Orientia tsutsugamushi‐Specific IgG/IgM Antibodies

Laboratory Diagnosis of Two Scrub Typhus Outbreaks at Camp Fuji, Japan in 2000 and 2001 by Enzyme-Linked Immunosorbent Assay, Rapid Flow Assay, and Western Blot Assay Using Outer Membrane 56-Kd Recombinant Proteins

“…24 The r56 antigen has been used successfully as a fused protein in passive hemagglutination assays 16 and an ELISA, 17 and in a truncated format in an ELISA and RFA. [13][14][15] In this report, we evaluated the ability of a new assay (KpKtGm r56 ELISA) to diagnose scrub typhus during an outbreak investigation utilizing sera collected from U.S. Marines training in Japan during two outbreaks of scrub typhus. 10,11 The recombinant protein antigens used in this assay were developed from the Karp, Kato, and Gilliam strains of O. tsutsugamushi.…”

“…The control line was purple for all tests conducted and was required for validity of the assays according to the manufacturer's instructions. 15 Western blot. The ELISA-and RFA-positive serum samples were assessed by Western blot analysis.…”

“…In this report, we describe the laboratory analysis of sera from 18 suspected cases and 46 controls from the two most recent outbreaks of scrub typhus at Camp Fuji using our standard trivalent (Karp, Kato, Gilliam) whole cell enzyme-linked immunosorbent assay (KpKtGm-wc ELISA), 12 and evaluating new assays using recombinant proteins: a cassette format rapid lateral flow assay (RCT) and an ELISA (Kp r56 ELISA) both using Kp recombinant 56-kD protein (r56), [13][14][15] and an ELISA and Western blot assay using r56 from the Karp, Kato, and Gilliam strains of O. tsutsugamushi (KpKtGm r56 ELISA and KpKtGm r56 Western blot, respectively). Recent studies with r56 from Karp in a passive hemagglutination assay, 16 ELISA, 13,17,18 and RCTs 14,15,18 have shown the utility of this new reagent when compared with previous assays that use whole cell antigens, including an ELISA, an indirect immunofluorescent antibody test, an indirect immunoperoxidase test , and a dot-blot immunoassay. The addition of r56 from other strains of O. tsutsugamushi, such as Gilliam and Boryong, has also proven effective.…”

Finger-actuated, self-contained immunoassay cassettes

“…Although home care tests such as dip-sticks and lateral flow immunochromatographic devices are widely available, they require the user to follow specific instructions and apply and blend reagents in a prescribed manner. This renders the tests practical only for relatively simple operations, and susceptible to both operator error and reagent contamination (Cardy and Allen 2004; Wilkinson et al 2003). To increase test robustness, it is desirable to minimize the user's involvement in performing process operations.…”

Rickettsial Infections Around the World, Part 2: Rickettsialpox, the Typhus Group, and Bioterrorism

“…Thus, a sensitive, rapid lateral flow assay that identifies Orientia tsutsugamushi-specific IgG/IgM antibodies is being developed. 51 Patients typically have a normal white blood cell count, with lymphocytosis in the majority of cases. About half of the patients have elevated aspartate aminotransferase and 20% have proteinuria.…”