Natural history of Ross River virus-induced epidemic polyarthritis

Andrea D Mylonas, Allison M Brown, Tracy L Carthew, David M Purdie, Nirmala Pandeya, Louisa G Collins, Andreas Suhrbier, Barry McGrath, Elizabeth J Reymond, Philip C Vecchio, Ian D Gardner and Ferdinandus J de Looze
Med J Aust 2002; 177 (7): 356-360. || doi: 10.5694/j.1326-5377.2002.tb04837.x
Published online: 7 October 2002


Objective: To describe the natural history, treatment and cost of Ross River virus-induced epidemic polyarthritis (RRV disease).

Design: Questionnaire-based longitudinal prospective study.

Participants and setting: Patients in the greater Brisbane area, Queensland, diagnosed with RRV disease by their general practitioners based on clinical symptoms and paired serological tests between November 1997 and April 1999.

Main outcome measures: Scores on two validated quality-of-life questionnaires (Clinical Health Assessment Questionnaire and Medical Outcomes Study Short Form 36) were obtained soon after diagnosis and one, two, three, six and 12 months thereafter. Scores were compared between patients diagnosed with RRV disease alone and those with RRV disease plus other conditions.

Results: 67 patients were enrolled. Most patients with RRV disease alone had severe acute symptoms, but followed a consistent path to recovery within three to six months. Other conditions, often chronic rheumatic diseases or depression, were identified in half the cohort; their quality-of-life scores suggested stable chronic illness between six and 12 months after diagnosis. Non-steroidal anti-inflammatory drugs (NSAIDs) were taken by 58% of patients (average use, 7.6 weeks; range, 2–22 weeks). Time off work averaged 1.9 days, and direct cost to the community was estimated as $A1018 per patient.

Conclusions: Symptom duration and frequency of long-term symptoms may have been overestimated by previous studies of RRV disease. Disease persisting six to 12 months after RRV diagnosis was largely attributable to other conditions, highlighting the need to seek other diagnoses in RRV patients with persistent symptoms.


The study was a prospective longitudinal survey carried out in Brisbane between November 1997 and April 2000.

Patient assessment

Patients attended an initial interview with a research nurse soon after the first positive IgM result, and were given an information leaflet and asked to sign a consent form. They were followed up one, two, three, six and 12 months later.

At each visit, they were asked to describe their medications, which were confirmed with the treating doctors. They were also asked to complete the Medical Outcomes Study Short Form 36 (SF-36)7 and the Clinical Health Assessment Questionnaire (CLINHAQ).8 The SF-36 questionnaire is used to assess health-related quality of life in a variety of diseases and conditions,9 while the CLINHAQ was developed primarily to assess patients with chronic rheumatic disorders.10

Premorbid diseases were documented at the first visit, and concurrent diseases at the first and subsequent visits, in consultation with patients and their doctors. Nearly all patients were also reviewed by a rheumatologist (P C V) to identify or confirm concurrent conditions at one to two months after diagnosis and, for those with suspected or confirmed comorbidities, again at three to six months after diagnosis.

Natural history of RRV disease

Frequency of pain in different joints at first interview is shown in Box 2. Knees, wrists and fingers were most often involved. The percentage of patients whose pain was symmetrical ranged from 36% (shoulder pain) to 100% (pain in the hands).

Mean SF-36 and CLINHAQ scores over the 12 months of follow-up are shown in Box 3. There was generally excellent concordance between the two measures, and both instruments illustrated that patients diagnosed with RRV disease alone tended to have a consistent path to recovery within three to six months. In contrast, the scores of patients diagnosed with RRV disease plus another condition usually failed to reach the population norm (defined as the score for the age- and sex-matched general Australian population). These patients usually had significantly worse illness at six and 12 months than those with RRV disease alone and also usually had stable chronic ill-health between the three- and 12-month reviews.

Twelve months after RRV diagnosis, 16 patients still had an SF-36 physical component (PC) score at least 5 points below the norm score of 50. They comprised:


This study illustrates that RRV disease is severe at onset but usually resolves within three to six months. Importantly, patients with continuing chronic disease beyond the three- to six-month follow-ups usually had additional conditions. These observations illustrate the importance of seeking differential diagnoses in patients presenting with long-term RRV disease.

These findings are consistent with those of a 1997 study of 103 Queensland residents with RRV disease, which also noted a high incidence of other rheumatic conditions.14 The high incidence of long-term RRV disease and long duration reported by other studies5 may be somewhat overestimated and unduly influenced by other chronic conditions. In our study, RRV disease lasting over a year was identified in only one patient with no confounding conditions (2% of the cohort).

At diagnosis, patients with RRV disease had SF-36 scores comparable to those of 55–64-year-olds with osteoarthritis awaiting hip or knee replacement surgery.15 Scores for both groups were 50–70 points lower than the norm for the domains role physical, physical function and body pain; 25–35 points lower for vitality, social function and role emotional; and 10–20 points lower for general and mental health. At diagnosis, our cohort also had similar SF-36 physical and mental component scores as patients with persistent Lyme disease,16 and similar average functional disability index and fatigue and pain scores as a US cohort of patients with chronic rheumatoid arthritis.7,17 Depression and anxiety scores in our patients at diagnosis approached the cutoff scores for clinical depression and anxiety (about 4 and 6, respectively) and were similar to those found in patients with rheumatoid arthritis three months after onset.17 Sleep problems have not been widely associated with RRV disease, but were also similar to those seen in chronic rheumatoid arthritis.17

A potential limitation of our study was the inability to enrol a greater percentage of eligible patients with RRV disease. The study was also of insufficient size to establish whether the single case of long-term RRV disease represents the true frequency.

To our knowledge, this study represents the first published use of validated questionnaires for investigating a viral arthritis and demonstrates their value for assessing these diseases. The results clearly highlight the need to consider alternative diagnoses in patients with persisting RRV disease symptoms. Patients with RRV disease can also be reassured that the disease, although severe at onset, is self-limiting, with a usual duration of three to six months, and does not have long-term sequelae.

3: Mean scores (± standard error) on two quality-of-life questionnaires for a cohort* with Ross River virus disease

Medical Outcomes Study Short Form 36 (SF-36)7

Clinical Health Assessment Questionnaire (CLINHAQ)8

* Survey included 67 patients (0 months), 64 (1 month), 62 (2 months), 61 (3 months), and 60 (6 and 12 months). All questions were completed on both questionnaires by 32 (RRV disease alone) and 28 (RRV disease plus other conditions) (0 months), 31 and 27 (1 month), 29 and 25 (2 months), 31 and 27 (3 months), 29 and 28 (6 months), and 30 and 27 (12 months). † SF-36 measures health on eight 100-point scales, where higher scores represent poorer health. Physical and Mental component scores are summary scores for the four physical and four emotional domains, respectively. "Role physical" and "Role emotional" represent role limitations due to physical and emotional problems, respectively.

‡ Higher scores on the CLINHAQ represent poorer health. § Scores differed significantly (P < 0.05) between patients with RRV disease alone and those with additional conditions, as determined by t test (SF-36 scores) or Wilcoxon rank-sum test (CLINHAQ scores). ¶ Physical component scores and sleep problem scores differed significantly (P = 0.01) between patients with RRV disease alone and those with RRV disease plus other conditions when the overall mean differences for all time points were compared by ANOVA.

Received 21 September 2002, accepted 22 May 2002

  • Andrea D Mylonas1
  • Allison M Brown2
  • Tracy L Carthew3
  • David M Purdie4
  • Nirmala Pandeya5
  • Louisa G Collins6
  • Andreas Suhrbier7
  • Barry McGrath8
  • Elizabeth J Reymond9
  • Philip C Vecchio10
  • Ian D Gardner11
  • Ferdinandus J de Looze12

  • 1 Australian Centre for International Health and Nutrition, Queensland Institute of Medical Research, Brisbane, QLD.
  • 2 Queensland Research and Health Promotion Unit, Royal Australian College of General Practitioners, Brisbane, QLD.
  • 3 Department of Rheumatology, Princess Alexandra Hospital, Brisbane, QLD.
  • 4 Department of Immunology, Queensland Medical Laboratory, Brisbane, QLD.
  • 5 University General Practice, University of Queensland, Brisbane, QLD.



We would like to thank the pathology companies Queensland Medical Laboratory and Sullivan and Nicolaides, Brisbane, QLD), Dr F Wolfe (Director, National Data Bank for Rheumatic Diseases, Kansas, USA), Dr J F Farmer (Brisbane), M Harris and Professor B Kay (Queensland Institute of Medical Research, Brisbane) for their contributions. The research was funded by Queensland Health, the Australian Rotary Health Research Fund (Arbovirus Prevention Research Grants), the Australian National Centre for International and Tropical Health and Nutrition, and the Queensland Institute of Medical Research Trust.

Competing interests:

None declared.

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