An outbreak investigation of scrub typhus in Western Province, Solomon Islands, 2014

Authors

  • Michael Marks Clinical Research Department, Faculty of Tropical and Infectious Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom; Hospital for Tropical Diseases, University College London Hospitals NHS Trust, London, United Kingdom
  • Cynthia Joshua Office of the WHO Representative in Solomon Islands, Honiara, Solomon Islands; Ministry of Health and Medical Services, Honiara, Solomon Islands
  • Jenny Longbottom Helena Goldie Hospital, Munda, Solomon Islands
  • Katherine Longbottom Helena Goldie Hospital, Munda, Solomon Islands
  • Alison Sio Office of the WHO Representative in Solomon Islands, Honiara, Solomon Islands; Ministry of Health and Medical Services, Honiara, Solomon Islands
  • Elliot Puiahi National Referral Hospital, Honiara, Solomon Islands
  • Greg Jilini Ministry of Health and Medical Services, Honiara, Solomon Islands
  • John Stenos Australian Rickettsial Reference Laboratory, Geelong, Australia
  • Tenneth Dalipanda Ministry of Health and Medical Services, Honiara, Solomon Islands
  • Jennie Musto Office of the WHO Representative in Solomon Islands, Honiara, Solomon Islands

DOI:

https://doi.org/10.5365/wpsar.2015.6.3.007

Abstract

Objective: To identify the etiology and risk factors of undifferentiated fever in a cluster of patients in Western Province, Solomon Islands, May 2014.

Methods: An outbreak investigation with a case control study was conducted. A case was defined as an inpatient in one hospital in Western Province, Solomon Islands with high fever (> 38.5 °C) and a negative malaria microscopy test admitted between 1 and 31 May 2014. Asymptomatic controls matched with the cases residentially were recruited in a ratio of 1:2. Serum samples from the subjects were tested for rickettsial infections using indirect micro-immunofluorescence assay.

Results: Nine cases met the outbreak case definition. All cases were male. An eschar was noted in five cases (55%), and one developed pneumonitis. We did not identify any environmental factors associated with illness. Serum samples of all five follow-up cases (100%) had strong-positive IgG responses to scrub typhus. Nine out of ten controls were negative for ST antibodies. Four controls had low levels of antibodies against spotted fever group rickettsia, and only one had a low-level response to typhus group rickettsia.

Discussion: This outbreak represents the first laboratory-confirmed outbreak of scrub typhus in the Western Province of Solomon Islands. The results suggest that rickettsial infections are more common than currently recognized as a cause of an acute febrile illness. A revised clinical case definition for rickettsial infections and treatment guidelines were developed and shared with provincial health staff for better surveillance and response to future outbreaks of a similar kind.

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Published

26-01-2016

How to Cite

1.
Marks M, Joshua C, Longbottom J, Longbottom K, Sio A, Puiahi E, Jilini G, Stenos J, Dalipanda T, Musto J. An outbreak investigation of scrub typhus in Western Province, Solomon Islands, 2014. Western Pac Surveill Response J [Internet]. 2016 Jan. 26 [cited 2026 Mar. 21];7(1). Available from: https://ojs.wpro.who.int/ojs/index.php/wpsar/article/view/392

Issue

Vol. 7 No. 1 (2016): January – March

Section

Outbreak Investigation Report

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