Many countries where scrub typhus is endemic use their own cutoff values for antibody titres to differentiate between cured cases and current infections. To establish an antibody titre cutoff value, one needs to investigate the seroprevalence in endemic areas, and the duration of the increase in titre after complete cure. We conducted a follow-up study of anti-Orientia tsutsugamushi antibody titres using indirect immunofluorescence assays (IFA) and passive haemagglutination assays (PHA) in patients with scrub typhus. After the onset of symptoms, IgM antibody titres increased gradually over 2-3 weeks, peaked at about 4 weeks, and started to decrease rapidly between 4 and 5 weeks. At 1-year follow-up, the median IgM value was 1:10. Out of 77 patients who were tested at that time, 36 (47%) had IgM titres > or =1:20, and none had titres exceeding 1:80. Over the first 2 weeks, IgG antibody titres increased sharply, peaked at about 4 weeks and decreased rather gradually thereafter, with a median titre of 1:128 maintained up to the 18th month. At 1-year follow-up, five out of 77 patients (6.5%) had titres > or =1:1,024 and 57% had titres > or =1:128. Based on these results, a cutoff value of > or =1:160 for IgM antibody should differentiate between previous and current infections in endemic areas such as Korea and Japan, where scrub typhus occurs mainly in the autumn.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.