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

Adenoviruses

Adenoviruses are DNA viruses which are clinically important because of their ability to cause acute respiratory infections and infections of the conjunctiva in humans. There are more than 47 serotypes of human adenoviruses. While human adenoviruses are ubiquitous with primary infection in the first year of life, there are geographical variations in the distributions of serotypes and associations of serotypes with different age groups. Broadly speaking, serotypes 1, 2, 5 and 6 are found in tonsils of young children, serotypes 3, 4 and 7 are found in young adults with upper respiratory tract infections, serotypes 8 and 19 are associated with adult eye infections and serotypes 11 and 21 are found in children with urinary tract infections.⁸ The adenovirus serotypes associated with clinical syndromes in different age groups are shown in Table 16.

Table 16. Adenovirus serotypes associated with clinical syndromes in different age groups*

Group affected	Syndromes	Adenovirus serotypes
Neonates	Fatal disseminated infection	3,7,21,30
Infants	Coryza, pharyngitis (most asymptomatic)	1,2,5
Children	Upper respiratory disease	1,2,4-6
	Pharyngoconjunctival fever	3,7
	Haemorrhagic cystitis	11,21
	Diarrhoea	2,3,5,40,41
	Intussuception	1,2,4,5
	Meningoencephalitis	2,6,7,12
Young adults	Acute respiratory disease and pneumonia	3,4,7
Adults	Epidemic keritoconjunctivitis	8,19,37
Immunocompromised	Pneumonia with dissemination, urinary tract infection	5,31,34,35,39,42-47
	CNS disease including encephalitis	7,12,32

*Adapted from reference 8

LabVISE laboratory reports of adenoviruses by year and serotype are shown in Table 17. Of the 13,924 reports, 10,826 were not further typed. Of the 2,468 serotypes identified, the most frequent serotypes identified in the period 1991 to 2000 were serotype 3 (687 reports, 28% of total), serotype 2 (591, 24%) and serotype 1 (513, 21%). In general, the proportion of untyped adenovirus reports increased from 63 per cent in 1991 to 86 per cent in 2000. The proportion of untyped adenovirus may reflect laboratory practices of batching samples for serotyping and the inability for LabVISE records to be updated with later serotyping information.

The age and sex distribution of adenovirus reports for the period 1991 to 2000 is shown in Figure 6. The male to female ratio was 1.3:1 and 58 per cent of the reports were from children aged less than 5 years.

Top of pageTable 17. Laboratory reports to LabVISE of adenovirus, 1991 to 2000, by year of report and serotype

Viruses	1991	1992	1993	1994	1995	1996	1997	1998	1999	2000	Total
Adenovirus type 3	88	96	203	57	66	45	22	57	35	18	687
Adenovirus type 2	142	129	128	45	37	29	39	22	13	7	591
Adenovirus type 1	91	111	85	48	32	21	29	74	14	8	513
Adenovirus type 40	4	6	9	-	-	34	12	21	74	86	246
Adenovirus type 8	38	33	55	55	22	13	3	3	1	3	226
Adenovirus type 4	23	103	40	2	2	-	7	4	15	5	201
Adenovirus type 5	31	38	28	12	14	9	8	1	6	8	155
Adenovirus type 7	8	4	11	16	26	17	8	17	7	8	122
Adenovirus type 11	29	12	4	1	3	1	-	1	-	-	51
Adenovirus type 37	7	3	1	2	2	5	3	5	11	11	50
Adenovirus type 19	6	20	3	-	3	7	-	2	1	7	49
Adenovirus type 6	9	7	3	1	2	3	-	20	-	3	48
Adenovirus type 9	11	7	5	3	2	1	-	-	-	-	29
Adenovirus type 26	11	-	2	2	2	1	-	-	-	-	18
Adenovirus type 28	12	1	1	-	-	1	-	-	-	-	15
Adenovirus type 30	7	2	-	1	2	-	-	-	-	-	12
Adenovirus type 35	4	1	1	1	1	3	-	-	-	-	11
Adenovirus type 10	4	2	1	-	1	-	1	1	-	-	10
Adenovirus type 22	3	1	1	3	-	-	-	2	-	-	10
Adenovirus type 46	1	3	1	2	2	-	-	-	-	-	9
Adenovirus type 41	-	-	-	-	-	4	3	-	-	1	8
Adenovirus type 12	-	3	3	-	-	-	-	-	-	-	6
Adenovirus type 29	5	-	-	-	-	-	-	-	-	-	5
Adenovirus type 24	3	-	-	-	-	-	-	-	-	-	3
Adenovirus type 31	3	-	-	-	-	-	-	-	-	-	3
Adenovirus type 47	1	2	-	-	-	-	-	-	-	-	3
Adenovirus type 16	2	-	-	-	-	-	-	-	-	-	2
Adenovirus type 34	-	2	-	-	-	-	-	-	-	-	2
Adenovirus type 42	-	-	-	-	1	1	-	-	-	-	2
Adenovirus type 13	1	-	-	-	-	-	-	-	-	-	1
Adenovirus type 14	1	-	-	-	-	-	-	-	-	-	1
Adenovirus type 15	-	-	-	-	-	-	-	-	-	1	1
Adenovirus type 18	1	-	-	-	-	-	-	-	-	-	1
Adenovirus type 21	1	-	-	-	-	-	-	-	-	-	1
Adenovirus type 27	1	-	-	-	-	-	-	-	-	-	1
Adenovirus type 32	1	-	-	-	-	-	-	-	-	-	1
Adenovirus type 43	-	-	-	-	-	1	-	-	-	-	1
Adenovirus type 44	1	-	-	-	-	-	-	-	-	-	1
Adenovirus type 45	2	-	-	-	-	-	-	-	-	-	2
Adenovirus not typed/pending	966	1,136	1,300	1,291	962	1,186	882	932	1,132	1,039	10,826
Total	1,518	1,722	1,885	1,542	1,182	1,382	1,017	1,162	1,309	1,205	13,924

Top of pageFigure 6. Laboratory reports to LabVISE of adenovirus infection, 1991 to 2000, by age and sex



LabVISE reports of adenoviruses in which diagnosis details were available were analysed. The majority of adenovirus reports came from patients with respiratory, gastrointestinal or eye disease (45% respiratory, 33% gastrointestinal and 11% eye disease).

It is estimated that adenoviruses account for between 2-4 per cent of acute respiratory infections, which cause 4.5 million deaths annually in children, mostly in the developing world.⁹ Adenoviruses also cause diarrhoea in children in developed countries. A prospective study in Canada has estimated that adenoviruses are responsible for around 4 per cent of community-acquired paediatric diarrhoea.¹⁰ Adenoviruses were identified in between 3.4 and 4.9 per cent of stools from children hospitalised with acute gastroenteritis in Melbourne between 1995 and 1998.¹¹

Adenovirus types vary in their geographic distribution and over time. Adenovirus type 41 infections increased in the Netherlands from 30 per cent to 95 per cent of all adenovirus infections between 1981 and 1986.¹² Adenovirus type 7 has been recorded as causing community and hospital outbreaks as well as sporadic cases in Australia.¹³ Seven genome types of adenovirus 7 have been identified and a shift from Ad7c to Ad7c genome types was observed to occur in the late 1960s in Europe and in the mid-1970s in Australia.¹⁴

Adenovirus infections are significant in the immunocompromised. Disseminated adenovirus disease (DAD) in neonates has been reported in recent years. A review of 11 DAD cases in Texas (6 of whom were immunocompromised and 5 who were immunocompetent) showed a high mortality rate (83%). Mortality was reduced by treatment with antiviral agents and immunoglobulin.¹⁵

In HIV-positive patients, adenovirus infection risk was estimated at 28 per cent per year and increased with declining CD4+ T-cell counts. Infection was most commonly gastrointestinal or urinary and prolonged viral shedding in severely immunocompromised has been noted.¹⁶

Respiratory infections with cytomegalovirus (CMV) and community respiratory viruses including adenoviruses are important causes of infection and morbidity and mortality among lung transplant recipients.¹⁷


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