Measles hot spots all over Australia

Overnight, New South Wales announced another two cases of measles bringing its total “since Christmas” to 30 cases.[1] Today Queensland announced another two as well. But perhaps more worrying is the very sudden but much quieter measles outbreak happening in the Northern Territory (NT).[10] Measles hot spots are popping up all over Australia.

Latest Measles cases reported from New South Wales (NSW)
Photo by Joey Csunyo on Unsplash

In 2014, Australia was officially certified by the World Health Organization (WHO) as having eliminated measles.[10,2] Measles is a vaccine-preventable disease, and Australia has good vaccine uptake. In a country free of transmission, any case is considered an outbreak. Generally speaking, twice the normal 7-18 day incubation period must pass before an outbreak ends.[17,18]

A transmission electron microscopic (TEM) image revealing the ultrastructural appearance of a single measles virus particle, or virion. The measles virus is 100-200 nm in diameter, with a core of single-stranded RNA.
Source: CDC PHIL. [16]

The cases Australia detects begin when an infected visitor or citizen returning from travel to countries without sufficient vaccine coverage. Sometimes, those cases pass the infection to others within Australia who are not adequately immunised. This transmission is especially obvious when it occurs in a pocket of unvaccinated people. Our high vaccine coverage means this doesn’t happen very often. But 2019 is turngin out to be a busy one.

2019 is seeing quite a few new measles cases

Measles hot spots have popped up all over Australia. Victoria is up to 9 cases for 2019 [2], South Australia has had 2 [4], Western Australia reports 15 [5], 1 has been reported from the Australian Capital Territory, Queensland has reported 9-11 [7-9] and Tasmania remains measles-free in 2019. Darwin in Australia’s Northern Territory recently reported 23 cases.[11] These aren’t all worryingly unusual numbers overall, but some are, and some are high for this early in the year.

Measles cases in Australian States and Territories.
Data from the
NATIONAL NOTIFIABLE DISEASES SURVEILLANCE SYSTEM

Is the Darwin outbreak still going?

The Northern Territory produced a series of media releases from early March, detailing a rapid rise in new Measles cases.

The first case was reported on February 7th. This was a Darwin resident returning from travel to Vietnam.[12] They visited the Palmerston Regional Hospital on the 15th and 17th of February. The second case also visited that hospital. The next media update, March 19, listed eight cases – four of them having been confirmed in the preceding two days.[13] There were no direct links between the previous and new cases.

The March 26th update listed 12 cases, all from around the local area.[14] The last update, March 28, described 23 cases and noted that initial measles-mumps-rubella vaccinations would now include 9-12-month-old babies, thus dropping the age at which the first of two vaccine doses are given by three months.[10] This final update noted that most cases so far were in adults. There were “well over” 1,000 contacts of cases.

Measles in the Northern Territory has been showing a worrying rate of new cases.

But that last report was over a week ago. Given how steep the curve (above) was up until the 28th, it’s very tempting to think that there have been more cases since then. But the national figures also haven’t moved so perhaps the outbreak was very quaikcly contained.

It is important to find out what’s happening in the NT. Messaging helps remind the local population about vaccination and boosters. Communication also alerts the rest of the country to the degree of risk to expect from travelling to, and in travellers from, the Darwin area.

Typical measles skin rash, 3 days after infection with measles virus.
Source: CDC PHIL. [15]

There are a lot of causes of fever and rash. Sometimes it’s hard to narrow down a likely culprit in the early stages of a disease. Travel and contact history help inform initial laboratory testing and management of patients. Knowing that travel from within Australia could be a factor – not just from a known overseas measles hot spot – is important information to have.

Stay tuned.

References

  1. Fresh alert as measles cases hit 30
    https://www.health.nsw.gov.au/news/Pages/20190404_00.aspx
  2. Elimination of endemic measles transmission in Australia
    https://www.who.int/bulletin/volumes/87/1/07-046375.pdf
  3. Vaccine preventable diseases summary | Victoria State Government
    https://www2.health.vic.gov.au/public-health/infectious-diseases/infectious-diseases-surveillance/search-infectious-diseases-data/vaccine-preventable-diseases-summary
  4. Measles case in Adelaide
    https://www.sahealth.sa.gov.au/wps/wcm/connect/public+content/sa+health+internet/protecting+public+health/alerts/health+alerts/measles+case+in+adelaide
  5. Measles Notifications | Department of Health, WA Government
    https://ww2.health.wa.gov.au/Articles/N_R/Notifiable-infectious-disease-report?report=measles
  6. Health alert: Measles case notified in Canberra
    https://www.health.act.gov.au/public-health-alert/health-alert-measles-case-notified-canberra
  7. Notifiable conditions reports: Summary information | Queensland Govt, Queensland Health
    https://www.health.qld.gov.au/clinical-practice/guidelines-procedures/diseases-infection/surveillance/reports/notifiable/summary
  8. National Notifiable Diseases Surveillance System (NNDSS) | Commonwealth of Australia
    http://www9.health.gov.au/cda/source/rpt_4.cfm
  9. Health authorities warn of a measles outbreak in Queensland’s north
    https://www.couriermail.com.au/news/queensland/health-authorities-warn-of-a-measles-outbreak-in-queenslands-north/news-story/31cbe8e761024a00b6393d036b528e9d
  10. Third Annual Meeting of the Regional Verification Commission for Measles Elimination in the Western Pacific | WHO WPRO
    https://apps.who.int/iris/bitstream/handle/10665/208616/RS_2014_GE_04_KOR_eng.pdf
  11. Measles Update – Vaccination program extended
    https://health.nt.gov.au/news/measles-update-vaccination-program-extended
  12. Measles alert
    https://health.nt.gov.au/news/measles-alert
  13. Further measles cases in Darwin
    https://health.nt.gov.au/news/further-measles-cases-in-darwin
  14. Update – Measles outbreak
    https://health.nt.gov.au/news/update-measles-outbreak
  15. Measles, CDC Public Health Image Library
    https://phil.cdc.gov/details.aspx?pid=3168
  16. Measles virus
    https://phil.cdc.gov/details.aspx?pid=8429
  17. Manual for the Surveillance of Vaccine-Preventable Diseases
    Chapter 7: Measles
    https://www.cdc.gov/vaccines/pubs/surv-manual/chpt07-measles.html
  18. Measles | National guidelines for public health units
    http://www.health.gov.au/internet/main/publishing.nsf/Content/cdna-song-measles.htm

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