Delivering a Healthy WA
Disease WAtch

December 2012, Volume 16, Issue 5

Full issue

Bali travel behind spike in dengue fever

Background
Dengue fever is a mosquito-borne acute viral infection caused by the dengue virus. It is endemic in most tropical and subtropical regions of the world, particularly Southeast Asia and Central and South America, reflecting distribution of the vectors Aedes aegypti and Aedes albopictus.

Dengue is not endemic in Australia but outbreaks occur in north Queensland where A. aegypti mosquitoes are established.

Signs and symptoms of dengue fever include fever, headache, retro-orbital pain, myalgia, arthralgia, rash, nausea and vomiting. The differential diagnosis in a returned traveler includes malaria, typhoid fever, measles, rubella, leptospirosis, scrub typhus and other arthropod-borne viral infections, such as chikungunya virus.

Dengue virus has 4 distinct serotypes. Infection with one serotype confers lifelong immunity to that serotype but a subsequent infection with another serotype increases the risk of dengue haemorrhagic fever.

Dengue fever in returned travelers

From January to September 2012, there was a dramatic increase in dengue fever notifications among WA residents with 484 cases reported. This was 1.5 times the number of cases reported in 2011 (318 cases) and almost equivalent to the record number in 2010 (494 cases). Of the more recent 484 cases notified in WA, just over half were males (55%), the median age was 40 years (range: 8-77 years), and 84 (17%) were hospitalised. The vast majority of cases (83%) were associated with travel to Indonesia. Of the Indonesian-acquired cases, 395 (96% overall) reported travel to Bali. The next most frequently reported countries of acquisition were Thailand, with 43 cases (9%), the Philippines (6), Malaysia (5), Vietnam (4), East Timor (3), Sri Lanka (2), Cambodia (2) and Singapore (2), as well as single cases associated with a range of other mostly South-East Asian countries.

An upward trend in notifications of dengue fever commenced in 2007 when 52 cases were reported following a 5-year annual average of 14 cases per year. Most of the infections were acquired in Bali. Official data on the incidence of dengue in Bali are lacking, however, local newspaper reports indicate periods of significant transmission of the disease, including a surge in cases in early 2012.

Figure 1 shows seasonal variation in dengue notifications by place of acquisition. Peaks in the Bali-acquired cases are likely a reflection of periods of increased mosquito activity.

Figure 1 is graph showing seasonal variation in dengue notification by place of acquisition.

Figure 1: Seasonal variation in dengue notifications by place of acquisition. (* Denotes January to September 2012.)

Laboratory data from the Bali-acquired dengue cases show that all 4 serotypes circulate in Bali, highlighting the risk of dengue haemorrhagic fever occurring in WA travelers with previous infections returning to Bali or other endemic areas.

In the year ending June 2012, Indonesia (primarily Bali) was the most popular holiday destination (328,000 visits) for Western Australians (Australian Bureau of Statistics data). It is therefore important that doctors advise people planning travel to Indonesia of the risks of contracting dengue fever and other mosquito-borne diseases. Travelers should be advised to use insect repellent during the day, including whilst indoors, because A. aegypti mosquitoes are day-time feeders and prefer to rest in cool dark areas. Likewise, doctors should consider dengue fever in persons with febrile illnesses who have recently travelled to Bali or other dengue-endemic regions.

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Almonds linked to Salmonella Typhimurium outbreak

In late September, notification numbers for Salmonella Typhimurium phage type 3 (STm PT 3) — a rare type of Salmonella in Australia — increased nationally.

Interviews of cases revealed that a high proportion had eaten raw almonds prior to becoming ill. In October, OzFoodNet, an Australia-wide network of epidemiologists, began a multi-jurisdictional outbreak investigation, working with food safety officers in each jurisdiction. It found more than 30 cases of salmonellosis were linked to this outbreak, with cases reported in all six states.

As the phage typing method for subtyping STm is not conducted in Western Australia, isolates of the outbreak strain were sent to WA from interstate for pulsed-field gel electrophoresis (PFGE) typing, which is the method used here for the subtyping of STm. The STm PT 3 isolates were found to be equivalent to PFGE type 0434, which has only recently been identified in WA. Five cases of PFGE type 0434 were identified in WA in September and October.

A national recall of Woolworths raw almond kernels was conducted on 4 October as a result of STm PT 3 being found in raw almonds. Close monitoring of STm isolates is continuing around the country.

All 5 WA cases reported regular almond consumption, with 2 confirming consumption of Woolworths raw almonds, specifically, prior to becoming ill. One case was aware of the product recall prior to interview because they had received an alert from Woolworths via their ‘Everyday Rewards’ loyalty card membership, which records all purchases made by the cardholder. Two cases had leftover almonds, which were submitted for testing. One almond sample was positive for STm PFGE type 0434.

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Measles outbreak highlights importance of immunisation

The recent measles outbreak in New South Wales has highlighted the importance of promoting the measles-mumps-rubella (MMR) vaccine for children under 5 years of age, adolescents and young adults.

A young adult returning home from overseas while infectious with measles caused the NSW outbreak in April. This person transmitted the virus to other susceptible contacts, which resulted in further clusters of cases in metropolitan Sydney.

In Australia, most measles cases occur in unvaccinated people who are infected overseas. However, most of the recent NSW cases had no history of overseas travel. This indicates the disease was spread within the local community to people who were unvaccinated or not fully vaccinated.

The highest notification rates of measles in NSW were in children younger than 5 years of age. This was largely as a result of transmission to infants under a year old who were too young to be vaccinated. The 15 to 19 year age group has also had high rates of measles, with several high schools affected. Persons of Pacific Island and Aboriginal backgrounds have been disproportionately affected. The majority of these cases were unvaccinated.

Measles is caused by a highly contagious virus that is spread from an infected person via respiratory droplets (through coughing and sneezing) or through the air. It can be a very severe disease. About 1 in 10 children with measles will get an ear infection and as many as 1 in 20 will develop pneumonia. About 1 in 1,000 will get encephalitis, and half in this group will die. Worldwide, there are an estimated 20 million cases of measles each year and 164,000 deaths resulting from the disease. More than half of these deaths occur in India.

Anyone exposed to measles who is not immune to the virus is likely to become infected with the disease. The infectious period is from 2 days before the onset of symptoms until 4 days after the rash has appeared. Measles symptoms include fever, followed by runny nose, conjunctivitis, cough and Koplic spots in the mouth. A few days later a rash appears on the face and works its way down the body and limbs.

It is important to recognise the early signs and symptoms of measles to prevent further spread. Anybody suspected of having measles should be encouraged to undertake appropriate testing (PDF 511KB), with specimens sent to PathWest for urgent processing. In addition, a notification form should be completed and sent to the Communicable Disease Control Directorate in metropolitan areas, and the local public health unit in regional areas.

Anybody who is infected, or is suspected of being infected, should be isolated from non-immune people and kept away from places such as the workplace, school and day care centres. They should remain isolated until the results of tests are available to determine appropriate management. This includes contact tracing of immediate household and social contacts. Local public health staff can assist with contact tracing.

The MMR vaccine is safe and effective and is recommended to be given at 12 months and 3.5 to 4 years of age. Two doses of vaccine, at least a month apart, will provide lifelong protection.

Children or adults born during or since 1966, who do not have evidence of measles infection or documented evidence of having received two doses of the MMR vaccine, are considered to be susceptible to measles and should be strongly encouraged to have the MMR vaccine.

Promoting immunisation

Measles can be prevented by immunisation. Health service providers are encouraged to alert parents to the importance of having their children fully immunised.

People planning overseas travel should be encouraged to ensure that they have received 2 doses of the MMR vaccine at least 1 month apart.

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West leads way in web-based vaccine ordering

Western Australia has become the first Australian jurisdiction to provide web-based vaccine ordering.

The convenient online system for ordering government-funded vaccines is now available statewide after a rollout to regional areas in June. It followed 18 months of use by immunisation service providers in the metropolitan area and a 6-month trial period in the Wheatbelt and Goldfields regions.

The online vaccine ordering system replaces the fax/phone-based process used previously by immunisation service providers.

Vaccines that can be ordered online include all childhood, year 7 and influenza vaccines funded by the Commonwealth; vaccines provided through state-funded programs such as the new-parent pertussis program; and influenza vaccines for children between the ages of 6 months and 5 years of age.

The online system does not fill orders of non-standard vaccines, such as hepatitis vaccines provided by the Sexual Health and Blood-Borne Virus program, and vaccines for migrant catch-ups and rabies.

Immunisation providers can access the online system by typing colors.csldirect.com.au into their web browser. Each practice that provides a vaccination service is allocated a unique username and password. Most practices should already have received these in the mail. Any that have not received these should email vaccineorders@health.wa.gov.au or telephone 9388 4835.

The username and password enables practices to log in to the system to place orders. A step-by-step user guide has also been sent to each provider practice.

Once an order is placed it goes to the vaccine orders team for approval. Approved orders destined for the metropolitan area are then shipped directly to practices. Orders destined for outside the metropolitan area are sent to one of 13 regional hospital pharmacies, which forward individual orders to the relevant providers in their region.

To date, 528 metropolitan-based providers and 297 regional-based immunisation providers are registered to receive government-funded vaccines in Western Australia. Over the past financial year, 11,280 orders have been shipped to 673 providers.

This amounts to 51,190 boxes of vaccine moving across Western Australia under carefully controlled cold chain conditions.

The online ordering system is a more rigorous and accountable system than its predecessor because it enables orders to be monitored and reported on with greater accuracy and timeliness. It has already helped to reduce vaccine wastage and leakage.

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New resources to aid in hepatitis C care

The Australasian Society for HIV Medicine (ASHM) has developed a new range of hepatitis C resources to support health professionals working with people who have been diagnosed with hepatitis C.

The four new resources now available are:

  • GPs and Hepatitis C: designed to assist GPs in their vital role of diagnosing, supporting, assessing, referring and treating people living with chronic hepatitis C.
  • Decision Making in HCV: a two-page laminate resource for GPs and practice nurses. It is a quick reference guide that can assist in evaluating hepatitis C laboratory results and making decisions about the management and treatment of patients with hepatitis C.
  • Nurses and Hepatitis C: developed for nurses who care for people living with hepatitis C. It is aligned with the Australasian Hepatology Association's Competency Standards for the Hepatology Nurse and the consensus-based Nursing Guidelines for the Care of Patients with Hepatitis B, Hepatitis C, Advanced Liver Disease and Hepatocellular Carcinoma.
  • Dental and Orofacial Health and Hepatitis C: an update written by dentists that provides an overview of the oral manifestations and complications associated with hepatitis C and its treatments.

ASHM resources can be accessed and ordered at www.ashm.org.au/resources.

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New call for action on HIV

A new call for action on HIV has been made at the 24th Australasian HIV/AIDS Conference held in Melbourne in October 2012.

The Melbourne Declaration seeks to galvanise Australia’s HIV testing, prevention and treatment responses to help it meet commitments made under the United Nations 2011 Political Declaration on HIV/AIDS.

The latest declaration, made in October, calls for increased access to HIV testing, treatment and pre-exposure prophylaxes, as well as a strengthened partnership response and enabling environment.

Read the July edition of Disease Watch for more information about the United Nations 2011 Political Declaration on HIV/AIDS.

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Australia adopts policy on testing for hepatitis B virus

Hepatitis B virus (HBV) infection is a major public health issue in Australia. An estimated 170,000 people in Australia are infected with hepatitis B and many more have been exposed to the virus1.

The impact of this disease is — and will continue to be — significant as the prevalence of HBV-related cirrhosis and hepatocellular carcinoma (HCC) continue to rise2. The majority of newly reported infections in Australia are chronic (of more than 6 months’ duration), occurring in people who have been infected at birth or during childhood in high-prevalence countries.

The National HBV Testing Policy is the first testing policy for this disease to be adopted in Australia. The purpose of the policy is to define appropriate testing pathways using currently available technologies. The policy is relevant for all health professionals ordering and interpreting tests for hepatitis B. The policy is not intended to be a resource for people with — or at risk of — hepatitis B.

The two priority populations for hepatitis B testing, as identified in the policy, are:

  • adults and children from culturally and linguistically diverse (CALD) backgrounds, particularly those born in countries of intermediate and high HBV prevalence
  • Aboriginal and Torres Strait Islander people.

Appropriate HBV testing will show whether an exposed individual has cleared the virus spontaneously or has become acutely or chronically infected.

Testing can also determine how advanced the infection is and assist with timing the start of anti-viral therapy. HBV infection can lead to cirrhosis and/or liver cancer (in up to 25% of people with chronic hepatitis B). Ongoing monitoring and timely treatment can help delay the onset of serious liver disease or liver cancer.

The policy contains information about principles of hepatitis B testing, diagnostic strategies, indications for testing, obtaining informed consent and conveying test results. Details about hepatitis B testing and the Medicare Benefits Schedule are also included.

A recent Disease WAtch article on Interpreting hepatitis B serology included a summary of components of hepatitis B serology.

Free online education material about hepatitis B and C is available for health professionals.

References

  1. www.med.unsw.edu.au/NCHECRweb.nsf/resources/2011/$file/KIRBY_ASR2011.pdf
  2. www.aihw.gov.au/publication-detail/?id=10737421461&tab=2

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Statement urges action on hepatitis

Politicians, governments, health departments and the wider community have been called to act urgently to prevent deaths caused by viral hepatitis.

The call is part of the Auckland Statement on Viral Hepatitis and was issued at the 8th Australasian Viral Hepatitis Conference in Auckland, New Zealand in September.

The statement calls for urgent measures to prevent new infections and stem rising rates of cirrhosis, liver cancer and preventable deaths.

The statement also sets targets for hepatitis B and C prevention, diagnosis and treatment, and identifies actions needed to achieve these. These actions include improved early diagnosis and timely access to quality treatment, care and support for those in need. Such measures would reduce the number of people with viral hepatitis who remained undiagnosed or unaware of how treatment could improve and extend their lives.

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Providers reminded of IPD vaccination recommendations for Aboriginal adults

Between 2009 and 2011, the rate of invasive pneumococcal disease (IPD) among Aboriginal people aged 15 to 49 years increased 2.5 times to 135 per 100,000 population (Figure 1). Most cases (80%) had predisposing medical conditions yet only 18% of these had ever received the 23-valent pneumococcal polysaccharide vaccine, Pneumovax 23.

Health providers are reminded that Pneumovax 23 is free for Aboriginal patients aged 15 to 49 years who have a medical condition that predisposes them to IPD (see The Australian Immunisation Handbook 9th ed 2008, page 246).

Graph showing Pneumococcal disease trends in Aboriginal and non-Aboriginal patients aged 15 to 49 years in WA

Figure 1: Pneumococcal disease trends in Aboriginal and non-Aboriginal patients aged 15 to 49 years, WA. (Note: different scales are used on the y-axes.)

The following table shows the schedule for the various adult cohorts for whom Pneumovax 23 is provided free under the National Immunisation Program. The number of doses of Pneumovax 23 required — one, two or three — varies according to the particular cohort’s risk of contracting severe pneumococcal disease. Note that a second dose of Pneumovax 23 is not recommended for healthy adult cohorts (non-Aboriginal adults over 65 years and Aboriginal adults over 50 years).

Immunisation schedule recommendations for Pneumovax 23


Risk group

Pneumovax 23

Dose 1

Dose 2

Dose 3

Non-Aboriginal adults ≥ 65 years

No further doses recommended

Non-Aboriginal adults < 65 years with underlying medical condition or smoker

√ as soon as practicable after diagnosis

√ 5 years after first dose

√ 5 years after second dose OR at 65 years (whichever is later)

Aboriginal adults ≥ 50 years

No further doses recommended

Aboriginal adults 15-49 years with underlying medical condition or smoker

√ as soon as practicable after diagnosis

√ 5 years after first dose

√ 5 years after second dose OR at 50 years (whichever is later)

Asplenic children and adults

√ as soon as practicable after diagnosis

√ 5 years after first dose

√ 5 years after second dose OR at 65 years (for non-Aboriginal adults) OR at 50 years (for Aboriginal adults), whichever is later

Recommendations in the above table are in line with Therapeutic Goods Administration (TGA) advice that a second dose of Pneumovax 23 be considered for patients at high risk of serious pneumococcal disease, provided that at least five years has passed since the previous dose was given.

This advice comes after a cluster of injection site reactions in NSW last year that involved cases who had been given a second dose of Pneumovax 23.

The TGA website has more information on Pneumovax 23 vaccination.

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Immunisation win for Wheatbelt

A three-pronged approach to improving immunisation rates in Western Australia's Wheatbelt region has proved a winner for the area, with immunisation rates for each of the main reporting ages — 12 months, 24 months, and 60 months — having risen over the past 3 years (Figures 1, 2 and 3).

The Wheatbelt area of Western Australia covers more than 154,000 square kilometres and has a population of approximately 71,000 residents. The Wheatbelt Population Health Service extends from Jurien Bay in the north, to Southern Cross in the east, and Darkan and Lake Grace in the south. It is divided into 4 districts, each centred around a major town in the area3.

A key role of the Wheatbelt Public Health Unit (WPHU) is to prevent and control communicable and non-communicable diseases through various methods and programs, including immunisation of children4. The Australian Childhood Immunisation Register is able to produce quarterly reports on immunisation rates within different regions. These rates are distributed by the Communicable Disease Control Directorate in Perth. The benchmark for immunisation rates outlined by the Coalition of Australian Governments Reform Council (2011)5 is 92.5%.

In 2008, immunisation rates in the Wheatbelt were below 90% in the 12 month and 60 month age groups. The WPHU have turned these figures around using the following measures.

Distributing monthly overdue reports

Monthly ACIR overdue reports are obtained and sent to the senior community nurses in each Wheatbelt district. The senior nurses distribute these overdue reports to the community nurses (school/child health) and each nurse follows up with the children on their list for that month. Follow-up involves contacting the parents of children who are overdue for immunisation by phone, SMS, letter and/or a home visit to arrange and provide immunisation. The reports are then updated and returned to the WPHU.

An updated master list of the children’s names is kept at the WPHU. This indicates whether each child is up to date with their immunisation, has been booked for immunisation, has moved house, is living overseas, has had natural immunity and/or conscientious objector forms signed on their behalf, has had medical contraindications to immunisation, is a non responder or still requires catch-up. Once the WPHU Administration Officer obtains the monthly reports from ACIR, a check is made against the master list and updated reports sent out.

Making immunisation a priority

Immunisation updates in the districts have highlighted the need to increase immunisation rates, and provide further education, training and support for staff. Particular emphasis has been placed on reducing the substantial gap between immunisation rates in Aboriginal and non-Aboriginal children.

Taking a team approach

The Wheatbelt has multi-skilled child and school health nurses who immunise children and adults. Immunisation occurs in a variety of venues including child health clinics (as part of routine appointments), at specific immunisation clinics in some towns, at the Wheatbelt Aboriginal Health Service, in schools during immunisation team visits, at hospital outpatient departments, GP surgeries or via home visits. Flexibility around immunisation provision has been a big factor in reducing the number of overdue children. For example, school nurses have successfully targeted kindergartens to perform catch-up immunisations.

The senior community nurses of each district are an important link in distributing the reports, supporting their staff and liaising with the public health nurses to provide feedback and strategies to improve the system.

Administrative staff members at the WPHU have played a vital role in the process of extracting reports from ACIR each month and separating them into districts and towns for distribution. They provide feedback to the senior staff and community nurses by providing percentages on the number of reports received each month. They have also helped streamline the system for reporting overdue immunisations by developing a template that makes completing the reports less time-consuming for nurses.

The Communicable Disease Control Directorate in Perth issues quarterly reports on immunisation rates for each public health unit, provide immunisation updates and develop statewide policy relating to immunisation, education and training in Western Australia.

Wheatbelt public health nurses have held overall control of the overdue reporting system. They provide staff with immunisation updates, encourage new staff to complete the immunisation training course and continue to seek ways of improving the system.

For the second quarter of 2012, the combined age-group rates were the highest in the State. Wheatbelt rates compare favourably with those in other states of Australia.

Note: Figures 1, 2 and 3 have been prepared using data provided by the Communicable Disease Control Directorate, Department of Health.

Yearly immunisation rates for 12-month age group in WA

Figure 1: Yearly immunisation rates for 12-month age group in WA Country Health Services (WACHS) public health units 2007 to 2012.

graph showing immunisation rates for 24-month age group in WACHS Public Health Units, 2007 to 2012.

Figure 2: Immunisation rates for 24-month age group in WACHS Public Health Units, 2007 to 2012.

Graph showing immunisation rates for 60-month age group in WACHS Public Health Units, December 2007 to 2012.

Figure 3: Immunisation rates for 60-month age group in WACHS Public Health Units, December 2007 to 2012.

References

  1. WA Country Health Service — Wheatbelt Regional Profile.
  2. Wheatbelt Population Health Core Functions, accessed from wachs.hdwa.health.wa.gov.au/index.php?id=4591
  3. COAG Reform Council, 2011, National Partnership Agreement on Essential Vaccines: Performance Report for April 2010-March 2011.

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