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Annual report National Notifiable Diseases Surveillance System, 2004
There were a number of outbreaks of infl uenza in
2004. Two outbreaks occurred in army barracks, one
in Victoria and another in Queensland. There were
13 outbreaks of infl uenza-like illness in 12 aged care
facilities in New South Wales, marked by high attack
rates (76% in residents and 42% in staff) and a case
fatality rate of 14 per cent.
Measles
Case defi nition – Measles
Both confirmed cases and probable cases
are notifi ed.
Confirmed case: Requires isolation of
measles virus or detection of measles virus
by nucleic acid testing OR detection of
measles virus antigen OR IgG seroconversion
or signifi cant increase in antibody level or
fourfold or greater rise in titre or detection of
measles specifi c IgM antibody in a reference
laboratory (except when vaccinated 8 days
to 8 weeks prior to testing) OR clinical illness
characterised by a maculopapular rash and
fever and cough, coryza, conjunctivitis or koplik
spots and epidemiological link to a laboratory
confi rmed case.
Probable case: Requires detection of measles
IgM antibody in other than an approved reference
laboratory and clinical illness.
There were 45 measles cases in 2004, including
43 confirmed and 2 probable cases; a national rate of
0.2 cases per 100,000 population. This was a 54 per
cent decrease compared with 2003 when 98 cases
were notified, and is the second lowest annual
rate for Australia since national surveillance began
in 1991 (Figure 41). The highest rate was in the
Northern Territory with 1.5 cases per 100,000 population
(3 cases), while the largest number of cases
were reported from Victoria (15 cases, 0.3 cases
per 100,000 population). In 2004 there were no
cases reported from the Australian Capital Territory,
Queensland or Tasmania (Tables 2 and 3).
Notifi cation rates were highest in the 25–29 year age
group (1.2 cases per 100,000 population), followed
by the 0–4 and 30–34 year age groups (0.5 cases
per 100,000 population, Figure 42). There were only
six cases in the under 5 year age group and three
were aged less than 1 year (0.8 cases per 100,000
population).
Figure 41. Notifications of measles, Australia,
1997 to 2004, by month of onset
Notifications
160
140
120
100
80
60
40
20
0
Measles control campaign
Jan-97
Jul
Jan-98
Jul
Jan-99
Jul
Jan-00
Jul
Jan-01
Jul
Jan-02
Jul
Jan-03
Jul
Jan-04
Jul
Month and year
Figure 42 shows trends in measles notification rates
by age group. In 2004 the largest proportion of
measles cases occurred in adults, which reflects the
success of measles vaccination programs in children
and adolescents. A recent review suggests that indigenous
transmission of measles has been interrupted
and that Australia is making good progress toward
measles elimination. 15
Figure 42. Trends in notification rates of
measles, Australia, 1999 to 2004, by age group
Rate per 100,000 population
14
12
10
8
6
4
2
0
1999 2000 2001 2002 2003 2004
Year
Of the 45 measles cases reported in 2004, 21 (46%)
occurred in six outbreaks in three states (Table 17).
The index case in four of the six outbreaks acquired
their infection outside Australia.
The outbreak in Western Australia is significant
because all six cases were in Indigenous people
and there was no link to a confi rmed imported index
case. These were the only measles notification in
Indigenous people in 2004, giving a rate of 1.2 per
100,000 population compared with 0.2 per 100,000
in non-Indigenous people (a rate ratio of 6:1).