The following background notes on toxoplasmosis in Australia and New Zealand are abstracted from Gideon www.GideonOnline.com and the Gideon e-book series. [1-3]

Australia:
An estimated 520 to 650 babies are born with congenital toxoplasmosis each year.

Prevalence surveys:
3.7% of encephalitis cases in Australia (221 cases reported, 1990 to 2007)

Seroprevalence surveys:
35% of pregnant women in Western Australia; 23% to 45% in Melbourne; 23% in South Australia; 26% in Queensland
50% of feral cats in Tasmania (1997 publication)
67% of captive common brushtail possums (Trichosurus vulpecula, 2008 publication)
15.5% of Western grey kangaroos in the Perth region (2009 publication)
5% of wild brush-tailed rock-wallaby populations in southeast Queensland (2010 publication)
0% of Australian fur seals (Arctocephalus pusillus doriferus, 2007 to 2009)

Cases of human infection have been ascribed to ingestion of poorly-cooked kangaroo meat.

High abortion rates are reported among pregnant Tasmanian ewes, which are infected through ingestion of cat feces.
- Toxoplasmosis has been demonstrated among humpbacked dolphins (Sousa chinensis) stranded in Queensland; and in common wombats (Vombatus ursinus)
- Toxoplasmosis has been reported in kakariki (Cyanoramphus spp.)

Notable outbreaks:
1984 (publication year) – An outbreak (5 cases) of toxoplasmosis among members of a Lebanese family in Australia was ascribed to contaminated Kibbi (a traditional meat dish)

New Zealand:
164 primary maternal infections are estimated annually, with resultant infection of 66 fetuses.
– The maternal seroconversion rate is 0.62% per year.

Seroprevalence surveys:
33% of pregnant women in Auckland (IgG, 2000)
42.9% of healthy blood donors in Waikato (2007 publication)
85% of ewes (2006 to 2009)

Toxoplasmosis has been documented in wallabies (Macropus eugenii, Macropus rufogriseus) exported to the United States from New Zealand.

References:
1. Berger SA. Infectious Diseases of Australia, 2011. 503 pp, 158 graphs, 2460 references. Gideon e-books, http://www.gideononline.com/ebooks/country/infectious-diseases-of-australia/
2. Berger SA. Infectious Diseases of New Zealand, 2011. 399 pp, 132 graphs, 1199 references. Gideon e-books, http://www.gideononline.com/ebooks/country/infectious-diseases-of-new-zealand/
3. Berger SA. Toxoplasmosis: Global Status, 2011. 92 pp, 74 graphs, 950 references. http://www.gideononline.com/ebooks/disease/toxoplasmosis-global-status/

A recent cluster of cases on Coff’s Coast reminds us that Q-fever continues to be a common disease in Australia. The following backgroud data are abstracted from the Gideon e-book series. [1,2] Primary references are available on request.

Time and Place:
- Q-fever was first characterized in Australia, in 1939.
- Queensland and New South Wales account for over 90% of cases.
- Over 50% of cases are directly, or indirectly related to meat processing.
- The male/female ratio for reported cases is approximately 5-to-1.

Disease rates have gradually increased over the past six decades – see graph:

Travel and Q-fever:
2002 (publication year) – Three Japanese workers acquired Q-fever while in Australia and New Zealand. 7
2005 – An American tourist acquired Q-fever in Australia. 8

Seroprevalence surveys:
18.5% of non-vaccinated meat workers in central Queensland (2001 publication)
6.5% of persons below age 25 years in South West Queensland (2010 publication)
66% of persons in Kimberly have evidence for prior exposure (2002)
7% of persons in the Hunter New England region of New South Wales (2006 to 2009)

The average rate among abattoir workers in Victoria is 6,600 per 100,000 during the first 10 years of exposure.
- As of 1996, vaccination programs were identified in one-third of abattoirs.
- Routine immunization of abattoir workers in endemic areas was introduced in 2002.
- As of 2009, vaccine update is 100% among abattoir workers and 43% among farmers.

The standard vaccine (‘Q-vax’) is prepared from Inactivated phase I whole Coxiella burnetii. A dose of 0.5 ml s.c. (deltoid region) is indicated for high-risk populations (eg, occupational exposure), and confers immunity for five years. Few sides effects are reported, and are limited to fever and headache.

A variety of local mammals serve as reservoirs, including the bandicoot (Isoodon torosus).
- Amblyomma triguttatum triguttatum ticks are implicated in the epidemiology of Q fever in Queensland.

Notable outbreaks:
1959 (publication year) – An outbreak of Q-fever in Queensland was associated with sheep contact.
1962 (publication year) – An outbreak was reported in a meat-works in South Australia.
1969 – An outbreak in a Brisbane ‘meat works’ affected 7.9% of workers.
1979 – An outbreak (110 cases) was reported at an abattoir in Victoria.
1998 – An outbreak (29 confirmed and 8 suspect cases) was reported at an abattoir in New South Wales.
2004 – An outbreak (9 confirmed and 6 suspect cases) was reported among farmers in South Australia.
2005 – An outbreak (5 cases) was reported among persons involved in calving activities, in New South Wales.
2006 (publication year) – An outbreak (4 cases) was reported among workers at a cosmetics factory.
2006 (publication year) – An outbreak (27 cases) was reported in rural South Australia.
2007 – An outbreak (5 cases confirmed, 1 possible fatal case) was associated with an abattoir in South Australia.

References:
1. Berger SA. Infectious Diseases of Australia, 2011. 503 pp., 158 graphs. Gideon e-book series, http://www.gideononline.com/ebooks/country/infectious-diseases-of-australia/
2. Berger SA. Q-fever: Global Status, 2011. 73 pp, 57 graphs. Gideon e-book series, http://www.gideononline.com/ebooks/disease/q-fever-global-status/

Update: Reported in ProMED

A recent outbreak in Adelaide reminds us that the salmonellosis rates in Australia have been increasing for more than five decades. In contrast, the incidence of this disease in other English-speaking countries has leveled off, or even decreased, since the 1990′s. 1,2 [see graph]

References:
1. Berger S. Infectious Diseases of Australia, 2011, 503 pp. Gideon e-book series, http://www.gideononline.com/ebooks/country/infectious-diseases-of-australia/
2. Berger S. Salmonellosis: Global Status, 2011, 245 pp. Gideon e-book series, http://www.gideononline.com/ebooks/disease/salmonellosis-global-status/

Rates of legionellosis in Australia and New Zealand have changed little since 2000, but remain somewhat higher than those of the United States and the U.K. – see graph:

The following background data are abstracted from the Gideon e-book series. 1,2 [primary references available on request]

Time and Place:
In Australia, highest legionellosis rates are reported during March to May.
- Legionella pneumophila infection peaks in summer and autumn, and L. longbeachae in spring.
- 69% of patients are males (1991 to 2000), and 71% of patients are above age 49 (1996).
- 2,170 cases of legionellosis were reported during 1991 to 2000.

L. longbeachae accounts for 22% of isolates nationwide, and is the predominant species in Western Australia (apparently associated with potting soils in South Australia).

22 outbreaks were reported during 1992 to 2000.

Notable outbreaks:
1986 – An outbreak of legionellosis was reported in South Australia.
1987 (publication year) – An outbreak of legionellosis was reported in Wollongong, New South Wales.
1987 – An outbreak (53 cases, 13 fatal) was reported in Illawarra, Southeast Sydney.
1992 – An outbreak (26 cases, 6 fatal) was associated with the Fairfield business district in Sydney.
1996 (publication year) – An outbreak (33 cases) was associated with a hotel car park in Sydney.
1998 (publication year) – An outbreak (11 cases) of community-acquired legionellosis was reported in Western Sydney.
1998 – An outbreak (58 cases, 7 fatal) was reported in Victoria. Of these, a cluster of 18 cases was linked to a contaminated cooling tower in a northern Melbourne suburb.
1998 – Two cases were reported among travelers returning from Bali.
2000 – An outbreak (125 confirmed cases; 2 fatal) was traced to a water cooling tower at the Melbourne Aquarium.
2002 (publication year) – An outbreak (5 cases) of Legionella longbeachae was reported in an intensive care unit.
2005 – An outbreak (12 cases) in the business district of Wollongong, New South Wales was ascribed to a contaminated cooling tower.

References:
1. Berger SA. Infectious Diseases of Australia, 2011. 503 pp. Gideon e-book series, http://www.gideononline.com/ebooks/country/infectious-diseases-of-australia/
2. Berger SA. Legionellosis: Global Status, 2011. 90 pp. Gideon e-book series. http://www.gideononline.com/ebooks/disease/legionellosis-global-status/

The report of a cluster of cases in Melbourne have added Australia to a growing list of countries endemic for Rickettsia felis infection. As of 2011, zoonotic and / or human disease has been reported in 32 countries. See map:

Recently, a man in New South Wales acquired eosinophilic meningitis (angiostrongyliasis) after ingesting a slug.

The 1st Australian case of human angiostrongyliasis was reported in 1971, in Brisbane.

At first, sporadic cases were reported only from coastal Queensland, northern New South Wales.

Four cases were reported in Victoria to 1999 (3 of these imported from Fiji; one fatal case).

Seropositivity is common among aboriginals.

Reservoirs:
The parasite has been identified in dogs in Sydney as well as in grey-headed fruit bats (Pteropus poliocephalus) Bennett’s wallaby (Macropus rufogriseus) rufous bettongs (Aepyprymnus rufescens) and captive tamarins (Sanguinus spp).

Further information regarding this, and all other diseases endemic to Australia, is available in Infectious Diseases of Australia. Los Angeles, Gideon Informatics, 2010. 488 pp. [edited] www.gideononline.com/ebooks/country/infectious-diseases-of-australia/

Update: Published in ProMED

A recent ProMED warning to backpackers is well taken – leptospirosis is a common disease in the Pacific region. In the following graphs I’ve compared disease rates for Australia and New Zealand with those of the United States.

Leptospirosis rates in nearby New Caledonia are even more striking, and exceed those of salmonellosis, hepatitis A, hepatitis B, gonorrhea, and tuberculosis.

The incidence of Hepatitis A in Australia has decreased dramatically in recent decades – from a high of 12,876 cases in 1962, to only 274 cases in 2008.

Since the 1970′s, rates of Hepatitis A in Australia have been strikingly similar to those of the United States (see graph):

Graph notes:
1.3. During 1991 to 1997, highest rates (52 per 100,000) were reported in the Northern Territory.
2. During 1991 to 2006, rates in New South Wales declined from 18.9 per 100,000 to 1.4 per 100,000.
Individual years:
1991 – 46.7% from New South Wales.
1994 – 39.7% from Northern Territory and 25.1% from Queensland.
1996 – 45.6% from New South Wales.
1997 – 47.3% from New South Wales.
1998 – 44.9% from Queensland and 37.8% from New South Wales.
2005 – 15.4% from Queensland and 25.5% from New South Wales.
2009 – Increasing rates in Victoria and South Australia appear to have been associated with ingestion of contaminated semi-dried tomatoes.

No fatal cases were reported during 1991 to 1997; 8 during 1998 to 2000.

570 cases were reported from eastern Sydney during 1991 to 1992, of which 58% were men who have sex with men.
– 236 cases were reported from south-eastern Sydney during June 1997 to May 1998 – over 60% of male cases acquired through homosexual contact; 118 during June 1998 to May 1999 – 29% through homosexual contact.

Seroprevalence surveys:
41.1% of Australians, 68.8% in the Northern Territory (1998)
75% of HIV-posititive MSM (2007 publication)
48% of homeless persons in Sydney (2003 to 2005)
3.0% of STD clinic patients (Canberra, 2000 to 2002)
37% of prisoners in New South Wales (1994)

Since 1993, hepatitis A has been the most common cause of infectious disease death among indigenous children in northern Queensland.
– Clinically apparent and severe hepatitis A are more common among indigenous children than their non-indigenous counterparts
– A vaccination program for this population was introduced in 1999.
– During 2003 to 2006, disease rates were 8.1 per 100,000 among indigenous people vs. 1.7 per 100,000 in other populations.

Notable outbreaks:
1970 (publication year) – An outbreak of Infectious hepatitis was reported in an institution.
1980 (publication year) – An outbreak (15 cases) was reported in a home for mentally-retarded children in Sydney. {p 6929674}
1991 – An outbreak (495 cases) in Melbourne involved men who have sex with men.
1993 – An outbreak (11 cases) was reported at a center for young people with developmental disabilities.
1996 (publication year) – An outbreak (7 cases) at a hospital in North Queensland may have been related to handling of contaminated bile.
1997 – An outbreak (7 cases) occurred among boys using a domestic spa in Melbourne.
1997 – An outbreak (270 cases or more) in New South Wales was traced to raw oysters.
1998 – An outbreak (45 cases) in Sydney was ascribed to illicit drug use.
2003 – An outbreak (10 cases) in Tasmania, Victoria and Queensland occurred among people who had been on tour in the Northern Territory.
2003 – An outbreak (21 cases) at a youth camp in central Australia was associated with ingestion of contaminated coleslaw.
2008 – An outbreak (15 cases) was associated with a cafe in Melbourne, Victoria.
2009 – An outbreak (200 cases) in Victoria was associated with consumption of semi-dried tomatoes.

A recent outbreak in Australia serves as a classic exercise in Epidemiology. Although Queensland and New South Wales account for most cases of Ross River disease, rates per 100,000 are consistently highest in Northern Territory.

Update: Referenced in ProMED

Just as the kangaroo is largely limited to Australia, a number of mosquito-borne viral infections are found almost exclusively in this country. In the following graph, I’ve contrasted reporting rates for six of these diseases. Sporadic infection by six additional viruses are also encountered in Australia: Sindbis, Stratford, Edge Hill, Gan Gan, Kokobara and Trubanaman.

Update: Reported in ProMED