Prevalence and risk factors for murine typhus, scrub typhus and spotted fever group rickettsioses among adolescent and adult patients presenting to Yangon General Hospital, Yangon, Myanmar

Abstract

Objectives: To inform patient management and disease prevention, we sought to estimate the prevalence of, and identify risk factors for, scrub typhus, murine typhus, and spotted fever group rickettsioses (SFGR) among febrile patients presenting to hospital in Myanmar.

Methods: We recruited patients ≥12 years old with fever ≥38°C among those seeking care at Yangon General Hospital from 5 October 2015 through 4 October 2016. Standardised clinical and risk factor assessments were conducted. Confirmed scrub typhus, murine typhus, and SFGR infections were defined as a positive polymerase chain reaction or ≥4-fold rise in immunofluorescence assay antibody titre to Orientia tsutsugamushi, Rickettsia typhi or Rickettsia honei or Rickettsia conorii, respectively. Probable infection was defined as IgM titre ≥1:400 to O. tsutsugamushi, an IgM titre of ≥1:800 or IgG ≥1:1600 to R. typhi or an IgG titre of ≥1:200 to R. honeii or R. conorii. Univariate and multivariable logistic regression was used to identify associations.

Results: Among 944 participants, the median (range) age was 37 (12-94) years, 444 (47.0%) were female, and 704 (74.6%) resided in rural areas. Among participants, 63 (6.7%) had confirmed or probable scrub typhus and 15 (1.6%) had confirmed or probable murine typhus. No SFGR infections were identified. The odds of confirmed or probable scrub typhus were lower among females than males (adjusted odds ratio [aOR] 0.5, p = 0.014), lower among those earning >300,000 Kyat per month compared with those earning less than 100,000 Kyat per month (aOR 0.28, p = 0.039), and higher among agricultural workers compared with others (aOR 2.9, p = 0.004).

Conclusion: Scrub typhus was common among patients presenting with fever in Yangon, murine typhus was uncommon, and SFGR was not found. Empiric treatment of severe febrile illness should include an antimicrobial with activity against rickettsial diseases. Public health campaigns targeting agricultural workers are recommended.

Keywords: Myanmar; Orientia tsutsugamushi; Rickettsia typhi; endemic flea‐borne typhus; epidemiology; fever; scrub typhus; spotted fever group rickettsiosis.

FIGURE 1

Study enrolment flow diagram, Yangon General Hospital, Myanmar, 2015–2016.