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Results - Part B: Analysis of data by pathogen, continued

Other respiratory RNA viruses

Reports grouped under the LabVISE category 'other RNA viruses' are largely agents of viral gastrointestinal illness. LabVISE reports of these viruses are shown in Table 34.

Table 34. Laboratory reports to LabVISE of 'other RNA viruses', 1991 to 2000

Virus	1991	1992	1993	1994	1995	1996	1997	1998	1999	2000	Total
Rotavirus	2,642	2,134	1,989	2,275	1,617	1,492	1,431	1,372	2,245	1,771	18,968
Norwalk-like virus	117	89	66	50	65	77	70	47	60	82	723
Astrovirus	21	14	4	1	6	3	4	10	3	-	66
Reovirus (unspecified)	8	12	7	3	-	-	-	-	2	2	34

Rotavirus

Reports of rotavirus infection were among the largest for any single virus in LabVISE (7.5% of total reports) between 1991 and 2000. Rotavirus infections are a common cause of diarrhoea in children and in Australia cause annual epidemics in the winter months (Figure 19).

Figure 19. Laboratory reports to LabVISE of rotavirus infection, 1991 to 2000, by month of specimen collection



Of the 1,771 reports of rotavirus in 2000, 1,556 (88%) were in children aged less than 5 years. From June 1999, a rotavirus surveillance program has been undertaken by the National Rotavirus Reference Centre, Royal Children's Hospital, Parkville, Victoria. Samples that test positive for rotaviruses by enzyme immunoassay or latex agglutination in collaborating laboratories are sent to the centre for serotyping. The Centre reports annually on circulating serotypes and outbreaks of rotavirus.⁴⁰

Norwalk-like virus

For the purposes of this analysis, Norwalk-like virus includes reports of 'Norwalk agent', 'calicivirus' and 'small virus-like particles. Norwalk-like virus (NLV) is the leading cause of outbreaks of diarrhoea and vomiting in the United Kingdom.⁴¹ These viruses are spread through contaminated food, aerosols, direct contact and environmental contamination. A recent report from the USA of a multi-state outbreak of NLV gastroenteritis associated with a common caterer, underlines the importance of this pathogen as food preparation becomes more centralised and distribution of products become more widespread.⁴²

Astrovirus, and reovirus (unspecified)

Small numbers of astroviruses and reoviruses were reported to LabVISE during the study period (Table 34).

Astroviruses are a common cause of infantile gastroenteritis worldwide both as sporadic cases and as outbreaks. A study of children aged less than 5 years in Melbourne between 1995 and 1998, confirmed astrovirus as the cause of acute gastroenteritis in 3 per cent of cases.¹¹

Reoviruses (unspecified) may include rotavirus. While reoviruses may cause human disease, infection is uncommon. Enteritis in infants and children and upper respiratory tract infections caused by reoviruses have been reported.⁴³


This article was published in Communicable Diseases Intelligence Volume 26, No 3, September 2002