Media Releases
Annual surveillance report of Rotavirus shows spread of new G9 strain
A report of the Australian Rotavirus Surveillance Program 2000/2001, shows there has been incidence of all strains of the gastroenteritis virus during the year in Australia, along with the a new and emerging G9 strain of the virus.
30 September 2001
CDI 02/01
Annual surveillance report of Rotavirus shows spread of new G9 strain
A report of the Australian Rotavirus Surveillance Program 2000/2001, featured in the latest edition of the Communicable Diseases Intelligence (CDI), published by the Communicable Diseases Network of Australia (CDNA), shows there has been incidence of all strains of the gastroenteritis virus during the year in Australia, along with the a new and emerging G9 strain of the virus.
Rotaviruses are the single most important cause of severe gastroenteritis in young children worldwide and the virus is responsible for the hospital admission of up to 10,000 children each year in Australia.
The national surveillance program was designed to monitor the serotype variation of rotaviruses prior to and after anticipated rotavirus vaccine release in Australia.
It showed that from the period June 2000 to May 2001, serotype G1 strains were the most prevalent overall (49 per cent) and found in all centres, serotype G9 rotaviruses, which were first identified in 1997, were second in importance (18.1 per cent).
Serotype G2 viruses were next (12.5 per cent), followed by the re-emergence of serotype G4 viruses (9.7 per cent).
The report suggests that these findings have implications for vaccine development strategies where protection against serotypes additional to G1-G4, may be required.
The surveillance report is highlighted by two outbreaks reported during the sampling period - a serotype G4 outbreak in Gove in the Northern Territory's Top End in September 2000 and a G9 outbreak in Alice Springs in May 2001.
According to Dr Paul Masendycz, from the National Rotavirus Reference Centre at the Royal Children's Hospital in Melbourne said last year Darwin had an outbreak of Rotavirus which moved east to isolated communities around Gove in Arnhem Land where children were admitted to hospital with acute gastroenteritis.
"A similar electropherotype was circulating in Sydney earlier in 2000, suggesting the virus had moved from Sydney to Darwin," Dr Masendycz said.
"Alice Springs experienced a large outbreak in May 2001 and serotype G9 was detected in children from widespread remote locations as far as the WA and SA borders.
"The outbreak put significant pressure on existing hospital facilities and highlights the need for a rotavirus vaccine effective against serotype G9 as well as serotypes G1-G4.
"The strain appears to have it origins in Perth where it was circulating from March to May 2001. Both the Alice Springs and Perth strains shared the same RNA elecropherotype.
"The subsequent northward spread of serotype G9 strains to Tennant Creek, Katherine and Darwin, suggests the newly emerging strain is capable of causing widespread morbidity"
Dr Masendycz said G1 viruses dominated in most centres and were present in all centres studied. This is consistent with previous studies undertaken in Australia, the UK and the USA.
"Ongoing surveillance of rotavirus serotypes is warranted due to the impact of new and emerging rotavirus serotypes," he said.
""This is particularly pertinent when considering the deleterious impact G9 rota viruses have had on the communities in and around Alice Springs in 2001.
"Variation in the predominant strains in different centres is important when considering the potential impact of vaccination and to inform the design of second and third generation vaccines."
The CDI is produced by the Federal Department of Health and Aged Care. The August edition is available on the internet at www.health.gov.au/pubhlth/cdi/cdicur.htm
Media contacts: Neil Branch, Communicable Diseases Network Australia, 0412 258 449
