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

Picornaviruses

The family Picornaviridae consists of two groups: the rhinoviruses and enteroviruses. Enteroviruses consist of five subgroups and these comprise a total of 67 serotypes: 31 echoviruses, 23 coxsackie A viruses, 6 coxsackie B viruses, 3 polioviruses and 4 'new' enteroviruses 68-71 (identified since 1970).³¹ Reports of Picornaviridae to LabVISE are shown in Table 21.

Table 21. Laboratory reports to LabVISE of Picornaviridae 1991 to 2000

Virus	1991	1992	1993	1994	1995	1996	1997	1998	1999	2000	Total
Enterovirus not typed	673	781	943	1,101	891	742	484	538	753	815	7,721
Rhinovirus (all types)	653	683	868	905	650	662	549	420	501	420	6,311
Echovirus	155	497	502	443	206	49	25	149	264	193	2,483
Poliovirus	194	186	121	106	71	35	24	44	52	40	873
Coxsackie B virus	155	136	113	87	21	49	27	18	21	32	659
Coxsackie A virus	58	43	82	36	12	22	10	12	25	19	319
Enterovirus 71	13	15	1	-	34	-	-	9	15	6	93

Enteroviruses (general)

Picornavirus reports averaged 7.5 per cent of the annual reports to LabVISE throughout the study period. Enteroviruses made up nearly two-thirds of the total picornavirus reports (12,148, 65%) and 4.7 per cent of the total LabVISE reports.

Of enteroviruses with typing information, echovirus comprised 56 per cent, poliovirus 19.7 per cent, Coxsackie B virus 14.9 per cent and coxsackie A virus 7.2 per cent.

Coxsackie A viruses

Coxsackie A viruses reported to LabVISE between 1991 and 2000 are shown in Table 22.

Table 22. Laboratory reports to LabVISE of coxsackie A virus, 1991 to 2000, by serotype

Virus	1991	1992	1993	1994	1995	1996	1997	1998	1999	2000	Total
Coxsackie virus A9	45	19	62	2	9	9	5	8	10	11	180
Coxsackie virus A16	9	21	18	34	1	12	5	3	15	8	126
Coxsackie virus A2	2	-	-	-	-	-	-	-	-	-	2
Coxsackie virus A10	-	-	-	-	1	-	-	1	-	-	2
Coxsackie virus A7	-	-	-	-	-	1	-	-	-	-	1
Coxsackie virus A21	-	-	1	-	-	-	-	-	-	-	1
Coxsackie virus A (untyped)	2	3	1	-	1	-	-	-	-	-	7
Total	58	43	82	36	12	22	10	12	25	19	319

Diagnoses in which coxsackie A viruses were identified were most commonly in patients with skin or mucous membrane disease (38%) and meningitis (21%), and most often identified in specimens of nasopharyngeal swabs (25%). Most coxsackie A viruses are not readily isolated by cell culture except serotypes A9 and A16. As a result these were the most commonly isolated serotypes reported by LabVISE. Coxsackie A9 infections have occurred in outbreaks in 1985, 1988 and 1993 (Figure 11).³⁰

Top of pageFigure 11. Laboratory reports to LabVISE of coxsackie A9 infections, 1991 to 2000, by month of specimen collection



This virus is associated with aseptic meningitis in adults and children. Coxsackie virus A16 is the etiologic agent of hand, foot and mouth disease. In Western countries, cases of this disease among children in the same family are often seen. The infection is typified by fever followed by the appearance of oral vesicles and peripheral exantham on the skin of the hands and feet.³¹ The clinical syndromes associated with coxsackie A viral infections are summarised in Table 23.

Table 23. Clinical syndromes associated with coxsackie A viral infection*

	Clinical syndrome	Coxsackie A serotypes
Illnesses associated with many enteroviruses in addition to coxsackie A	Aseptic meningitis Encephalitis Paralysis	1-11,14, 16-18, 22, 24 2,5,6,7,9 4,6,7,9,11,14,21
Illnesses more characteristic of particular groups or serotypes of coxsackie A	Herpangina Hand, foot and mouth syndrome Exanthem Epidemic conjunctivitis	2-6, 8, 10, 22 5,7,9,10,16 2,4,5,9,16 24
Undefined/uncertain etiologic role of coxsackie A viruses	Haemolytic uraemic syndrome Myositis Guillain-Barré syndrome Mononucleosis	4 9 2,5,9 5,6

*Modified from reference 31

Coxsackie B viruses

Coxsackie B viruses were most often identified in patients presenting with meningitis (31%), lower respiratory tract illness (18%) and gastroenteritis (11%). Specimens of nasopharyngeal swabs (32%), faeces (26%) or cerebrospinal fluid (23%) were the most common sources.

Coxsackie B4 and B5 were the most common serotypes of coxsackie B viruses identified in LabVISE. Coxsackie B4 is associated with respiratory disease (summer gripe) mostly in children under 5 years of age. Coxsackie B5 is associated with meningitis and occurs in children and adults.³¹

Coxsackie B serotypes identified in LabVISE reports between 1991 and 2000 are shown in Table 24.

Table 24. Laboratory reports to LabVISE of coxsackie B viruses, 1991 to 2000, by year and serotype

Virus	1991	1992	1993	1994	1995	1996	1997	1998	1999	2000	Total
Coxsackie virus B5	40	65	26	15	4	15	1	7	7	5	185
Coxsackie virus B4	61	4	11	12	2	8	5	6	3	16	128
Coxsackie virus B1	6	57	51	4	-	-	1	-	1	4	124
Coxsackie virus B2	34	2	8	23	4	20	6	1	10	6	114
Coxsackie virus B3	13	6	15	31	11	3	14	2	-	-	95
Coxsackie virus B6	-	1	1	2	-	-	-	1	-	-	5
Coxsackie virus B untyped	1	1	1	-	-	3	-	1	-	1	8
Total	155	136	113	87	21	49	27	18	21	32	659

There were a number of outbreaks of coxsackie B4 viruses in 1991, 1993-1994, 1996 and 2000. Coxsackie B5 outbreaks occurred in 1991-1992, 1993 and 1996 (Figure 12).

Top of pageFigure 12. Laboratory reports to LabVISE of coxsackie B4 and B5 viruses, 1991 to 2000, by month of specimen collection



The clinical syndromes associated with coxsackie B viral infection are summarised in Table 25.

Table 25. Clinical syndromes associated with coxsackie B viral infection*

	Clinical syndrome	Coxsackie   B serotypes
Illnesses associated with many enteroviruses in addition to coxsackie B viruses	Aseptic meningitis Encephalitis Paralysis	1-6 1-3,5,6 1-6
Illnesses more characteristic of particular groups or serotypes of coxsackie B viruses	Exanthem Pleurodynia Pericarditis Myocarditis Generalised disease of the newborn	1,3,4,5 1-5 1-5 1-5 1-5
Undefined/uncertain etiologic role of coxsackie B viruses	Haemolytic uraemic syndrome Mononucleosis-like syndrome	2,4 5

*Modified from reference 31

Echoviruses

Echoviruses identified in LabVISE reports between 1991 and 2000 are shown in Table 26.

Table 26. Laboratory reports to LabVISE of echovirus, 1991 to 2000, by serotype

Virus	1991	1992	1993	1994	1995	1996	1997	1998	1999	2000	Total
Echovirus type 30	1	3	198	247	28	3	1	26	17	121	645
Echovirus type 11	10	13	141	26	4	1	5	50	166	7	423
Echovirus type 9	5	216	22	7	41	4	1	22	32	5	355
Echovirus type 6	9	85	10	107	12	1	1	5	16	1	247
Echovirus type 7	4	39	74	-	2	24	4	-	1	33	181
Echovirus type 17	59	38	4	-	-	-	-	2	-	-	103
Echovirus type 22	19	13	9	9	13	1	1	14	12	8	99
Echovirus type 14	7	15	23	12	35	4	-	1	-	1	98
Echovirus type 3	-	-	-	27	16	-	-	-	5	2	50
Echovirus type 25	2	31	5	1	3	-	-	-	3	-	45
Echovirus type 18	3	3	1	2	2	1	-	15	-	1	28
Echovirus type 4	2	14	-	-	1	1	1	5	1	-	25
Echovirus type 5	3	2	5	1	-	4	4	5	1	-	25
Echovirus type 16	14	9	-	-	-	-	-	-	-	-	23
Echovirus type 1	4	1	-	-	3	-	-	1	-	3	12
Echovirus type 33	1	-	-	-	1	1	1	-	4	4	12
Echovirus type 21	2	4	4	-	-	-	-	-	-	-	10
Echovirus type 31	1	1	-	-	1	-	1	-	1	2	7
Echovirus type 15	1	-	3	-	1	1	-	-	-	-	6
Echovirus type 24	2	1	-	-	3	-	-	-	-	-	6
Echovirus type 19	-	2	1	-	-	-	-	-	1	-	4
Echovirus type 2	-	1	-	-	-	-	1	1	1	-	4
Echovirus type 20	-	3	-	-	-	-	-	-	-	-	3
Echovirus type 23	-	-	-	1	1	-	-	-	-	-	2
Echovirus type 32	2	-	-	-	-	-	-	-	-	-	2
Echovirus type 8	-	2	-	-	-	-	-	-	-	-	2
Echovirus type 34	1	-	-	-	-	-	1	-	-	-	2
Echovirus type 12	-	-	1	-	-	-	-	-	-	-	1
Echovirus type 13	-	-	-	-	1	-	-	-	-	-	1
Echovirus not typed/pending	3	1	1	3	38	3	3	2	3	5	62
Total	155	497	502	443	206	49	25	149	264	193	2,483

The most commonly identified echovirus serotypes during the study period were echovirus types 30, 11 and 9. Diagnoses in which echoviruses were identified were predominantly in cases of meningitis (41%) and were often isolated from cerebrospinal fluid.

Echovirus 30 was the most common echovirus serotype identified in LabVISE during the study period. Echovirus 30 has caused large outbreaks of aseptic meningitis in many regions of the world during the last 40 years. Periods of increased reporting of echovirus 30 were evident in 1993 to 1994 and again in 2000 (Figure 13).

Top of pageFigure 13. Laboratory reports to LabVISE of echovirus 30, 1991 to 2000, by month of specimen collection



Periods of increased activity of echovirus 11 associated with aseptic meningitis occurred at intervals of 2-4 years with major peaks in 1993 and 1999. More than half the cases were in children under 5 years (Figure 14).

Figure 14. Laboratory reports to LabVISE of echovirus 11, 1991 to 2000, by month of specimen collection



The clinical syndromes associated with infection with echovirus are shown in Table 27.

Top of pageTable 27. Clinical syndromes associated with echoviruses*

	Clinical syndrome	Associated echovirus serotypes
Illnesses associated with many enteroviruses in addition to echoviruses	Aseptic meningitis Encephalitis Paralysis	All except 24,26,29,32 2-4,6,7,9,11,14,17-19,25 1-4,6,7,9,11,14,16,18,19,30
Illnesses more characteristic of particular groups or serotypes of echovirus	Exanthem Generalised disease of the newborn Neonatal diarrhoea Chronic meningoencephalitis in agammaglobulinemics	9,16 also 1-8,11,14,18,19,25,30,32,33 4,6,7,9,11,12,14,19,21,51 11,14,18 2,3,5,9,11,19,24,25,30,33
Undefined/uncertain etiologic role for echovirus	Myositis Haemolytic uraemic syndrome Guillan-Barré syndrome Infectious lymphocytosis	9,11 22 6,22 25

*Modified from reference 31

Polioviruses

Polioviruses are the cause of poliomyelitis, an infection of the central nervous system, which may result in acute flaccid paralysis. Poliovirus infection occurs via the gastrointestinal tract and in more than 90 per cent of cases, causes an inapparent infection.²⁴ Acute flaccid paralysis occurs in less than one per cent of infections. Three serotypes are recognised and immunity is serotype specific.³¹ The oral polio vaccine, which has been in widespread use in Australia and throughout the world for the last 50 years, is a mixture of the three serotypes. Naturally occurring ('wild type') or live attenuated vaccine polioviruses circulate to a varying extent, depending on the impact of polio vaccine on transmission.³¹

Oral polio vaccination has placed the global eradication of poliomyelitis within reach. Numerous regions of the world, including the Western Pacific Region (which includes Australia) have been declared polio-free. The last case of poliomyelitis in Australia occurred in 1972 and the Western Pacific Region was declared polio-free in October 2000. However, continued surveillance is required since there is a continuing possibility of importation of cases of poliovirus from endemic areas. Surveillance for poliovirus in Australia comprises reporting of poliomyelitis as a notifiable disease to the NNDSS, surveillance of all cases of acute flaccid paralysis, surveillance of vaccine associated paralytic polio cases, surveillance of enteroviruses and intratypic differentiation of all polioviruses isolated in Australia.

Poliovirus laboratory reports to LabVISE between 1991 and 2000 are shown in Table 28.

Table 28. Laboratory reports to LabVISE of poliovirus, 1991 to 2000, by type

Virus	1991	1992	1993	1994	1995	1996	1997	1998	1999	2000	Total
Poliovirus type 1 (uncharacterised)	40	71	43	41	27	15	9	12	26	22	306
Poliovirus type 2 (uncharacterised)	54	45	35	41	29	14	9	25	16	8	276
Poliovirus type 3 (uncharacterised)	26	32	31	14	13	1	4	6	8	8	143
Poliovirus type 1 (vaccine strain)	-	-	-	-	-	1	-	1	-	-	2
Poliovirus type 2 (vaccine strain)	-	-	-	-	-	2	2	-	1	-	5
Poliovirus type 3 (vaccine strain)	-	-	-	-	-	-	-	-	-	1	1
Poliovirus not typed/pending	74	38	12	10	2	2	-	-	1	1	144

Thirty-seven per cent of poliovirus diagnoses were associated with a diagnosis of gastrointestinal disease and 50 per cent of the specimens in which poliovirus was identified were stool samples. No wild-type poliovirus has been isolated from any case of acute flaccid paralysis.³² Continued surveillance of poliovirus will be required until the circulation of wild-type polio can be shown to have ceased. There is concern over the potential for live attenuated virus from the oral polio vaccine persisting in water supplies and possibly reverting toward wild-type neurovirulent phenotypes. This is one reason some countries such as the USA have changed to using an inactivated polio vaccine.³³

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Enteroviruses 71 and enterovirus (not typed)

Since the revision of the classification system of the taxonomic scheme for picornaviruses in 1970, four new serotypes have been discovered. These are enteroviruses 68-71. These 'new' enteroviruses are associated with distinct clinical symptoms and show a defined geographical distribution. In Australia, only enteroviruses 70 and 71 have been reported. Infections with enterovirus 70 occurred in a cluster in New South Wales in 1990, but since then, there have been no more reports of this virus to LabVISE.³⁰

Enterovirus 71, the most recently discovered enterovirus has been recognised as a cause of cutaneous and central nervous system disease since 1969. Enterovirus 71 is the only non-poliovirus enterovirus known to have the potential to cause epidemic paralytic disease.

The relatively large number of untyped enteroviruses may reflect laboratory practices whereby reports to LabVISE are made only on initial identification or after exclusion of polioviruses, and further identification data are not sent.

Report to LabVISE of enterovirus 71 and enterovirus (untyped) are shown in Table 29.

Table 29. Laboratory reports to LabVISE of enterovirus 71 and enterovirus (untyped), 1991 to 2000

Virus	1991	1992	1993	1994	1995	1996	1997	1998	1999	2000	Total
Enterovirus type 71	13	15	1	-	34	-	-	9	15	6	93
Enterovirus not typed/pending	673	781	943	1,101	891	742	484	538	753	815	7,721

Enterovirus 71 was first reported in Australia in 1972. A major outbreak of enterovirus 71 occurred in south-east Australia in 1986. Clinical diagnosis during this outbreak was largely skin and mucous membrane disease, meningitis (23%) and respiratory disease (20%).³⁰ An outbreak of hand, foot, and mouth disease caused by an enterovirus was reported in Western Australia in 1999.³⁴ In this outbreak, nine of 14 (64%) children developed neurological disease and four of these had long-term sequelae.

Rhinovirus

Rhinoviruses are a cause of the common cold with a worldwide distribution.³⁵] Rhinoviruses infect humans from early childhood with recurrent infection throughout life. In temperate regions, there are annual seasonal peaks in incidence. Rhinovirus laboratory reports to LabVISE between 1991 and 2000 are shown in Table 30. [Table 30. Laboratory reports to LabVISE of rhinovirus, 1991 to 2000

Virus	1991	1992	1993	1994	1995	1996	1997	1998	1999	2000	Total
Rhinovirus (all types)	653	683	868	905	650	662	549	420	501	420	6,311

LabVISE reports of rhinovirus show an annual peak in late winter and early spring (Figure 15).

Figure 15. Laboratory reports to LabVISE of rhinovirus infections, 1991 to 2000, by month of specimen collection




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