The Laboratory Virology and Serology Reporting Scheme, 1991 to 2000

The Laboratory Virology and Serology (LabVISE) Reporting Scheme is a passive surveillance scheme based on voluntary reports of infectious agents contributed by virology and serology laboratories around Australia. This article reports on the LabVISE data collected between 1991 and 2000 and was published in Communicable Diseases Intelligence Vol 26 No 3, September 2002. This article can be viewed in 15 HTML documents and is also available in PDF format.

Page last updated: 03 October 2002

A print friendly PDF version is available from this Communicable Diseases Intelligence issue's table of contents.




Other non-viral pathogens

Chlamydial infections

Chlamydiae are a unique class of bacteria that are obligate intracellular parasites. Three Chlamydia species are recognised, all of which are human pathogens: C. trachomatis, C. pneumoniae and C. psittaci. The associated diseases, strains, mode of infection and host species are shown in Table 35.

Table 35. Characteristics of Chlamydia spp. and strains, modes of transmission and associated human diseases*

Species
Strains
Mode of transmission
Host species
Associated human diseases
C. trachomatis LGV (L1, L2, L3) Sexual Humans Lymphogranuloma venereum
Trachoma (A,B,Ba,C) Hand to eye, fomites, flies Humans Ocular trachoma
Trachoma (B,Ba,D-K) Sexual, hand to eye, neonatal Humans Ocular and genital disease, infant pneumonia
C. psittaci Many Aerosol Birds, sheep, cats etc Ornithosis (psittacosis)
C. pneumoniae 'TWAR' Not defined aerosol? Humans Bronchitis, pneumonia

*Adapted from reference 44


Reports of chlamydial infections to LabVISE are shown in Table 36.

Table 36. Laboratory reports to LabVISE of chlamydial infections, 1991 to 2000

Organism
1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 Total
Chlamydia trachomatis A-K
59
11
-
1
1
1
1
-
1
-
75
Chlamydia trachomatis L1-L3
18
-
-
-
-
-
1
-
-
-
19
Chlamydia trachomatis not typed
2,615
2,563
2,835
2,178
2,579
3,803
3,980
3,158
3,295
3,154
30,160
Chlamydia pneumoniae
2
14
1
-
2
1
3
-
2
36
61
Chlamydia psittaci
139
97
74
114
176
62
51
70
78
102
963
Chlamydia spp. typing pending
1
10
9
10
6
1
7
-
1
-
45
Chlamydia species not typed
-
6
18
62
75
54
28
57
21
8
329
Total
2,834
2,701
2,937
2,365
2,839
3,922
4,071
3,285
3,398
3,300
31,652


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Chlamydia trachomatis

Notifications of Chlamydial trachomatis infection between 1991 and 2000 to the NNDSS and laboratory reports to LabVISE are shown in Table 37.

Table 37. Laboratory reports to LabVISE and notifications to NNDSS of Chlamydia trachomatis infections, 1991 to 2000

Surveillance system
1991 1992 1993 1994 1995 1996 1997 1998 1999 2000
LabVISE
2,692
2,574
2,835
2,179
2,580
3,804
3,982
3,158
3,296
3,154
NNDSS
4,044
6,293
6,500
6,450
6,398
8,445
9,242
11,339
14,082
16,853


The NNDSS case definition for chlamydial infections requires the isolation of Chlamydia trachomatis or demonstration of chlamydial antigens in clinical specimens. For most of the study period and from most jurisdictions, notifications to the NNDSS of chlamydial infections were restricted to genital chlamydial infections. New South Wales did not start reporting chlamydial infections to the NNDSS until 1998. LabVISE laboratory reports have fallen from representing two-thirds of the NNDSS reports in 1991 to just 19 per cent in 2000. Whether laboratory reports in LabVISE were from clinical samples only from genital sites or whether they include samples from other infected sites cannot be determined.

The distribution of chlamydial infections by age and sex, reported to LabVISE are shown in Figure 20. The distribution is very similar to that seen in NNDSS notifications, with a female predominance (male to female ratio of 1:1.6) and the largest number of reports (57%) from young adults aged 15-24 years.

Figure 20. Laboratory reports to LabVISE of Chlamydia trachomatis infection, 1991 to 2000, by age and sex

Figure 20. Laboratory reports to LabVISE of Chlamydia trachomatis infection, 1991 to 2000, by age and sex

Chlamydia psittaci

Notifications of Chlamydia psittaci infection between 1991 and 2000 to the NNDSS and laboratory reports to LabVISE are shown in Table 38.

Table 38. Laboratory reports to LabVISE and notifications to NNDSS of Chlamydia psittaci infections (ornithosis), 1991 to 2000

Surveillance system
1991 1992 1993 1994 1995 1996 1997 1998 1999 2000
LabVISE
139
97
74
114
176
62
51
70
78
102
NNDSS
136
98
94
86
186
86
35
64
84
100


Ornithosis has not been a notifiable disease in all Australian jurisdictions during the period 1991 to 2000 and consequently cases reported to the NNDSS do not represent national figures. While no agreed national NNDSS definition for ornithosis was used in this period, probable cases diagnosed based on an acute clinical illness compatible with ornithosis, were included. Laboratory diagnosis is based on increases in specific antibody titres, or more recently, detection of C. psittaci by nucleic acid tests.

For a number of years, LabVISE reported more cases of ornithosis than the NNDSS. LabVISE reports showed a male predominance (male to female ratio 1.7:1) and a peak of reports from adult men aged 50-54 years. Figure 21 shows the age and sex distribution of laboratory reports of ornithosis to LabVISE. This age and sex distribution is similar to that found in notifications of ornithosis to NNDSS.

Figure 21. Laboratory reports to LabVISE of Chlamydia psittaci infections, 1991 to 2000, by age and sex

Figure 21. Laboratory reports to LabVISE of Chlamydia psittaci infections, 1991 to 2000, by age and sex

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Chlamydia pneumoniae

Chlamydia pneumoniae causes an acute respiratory disease similar to that caused by Mycoplasma. Infection is widespread and antibody prevalence is low in children, around 50 per cent in young adults and continues to be high into old age. Clinical disease is seen in all ages but most frequently in young adults.24

Mycoplasma pneumoniae

Mycoplasma pneumoniae is the cause of mycoplasma pneumonia (or primary atypical pneumonia), that presents predominantly as a febrile lower respiratory infection or occasionally as a pharyngitis, bronchitis or pneumonia.24 The disease is worldwide in distribution and may occur in all age groups with occasional epidemics in institutions and military recruits.

Laboratory reports to LabVISE of Mycoplasma between 1991 and 2000 are shown in Table 39.

Table 39. Laboratory reports to LabVISE, of Mycoplasma infections, 1991 to 2000

Organism
1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 Total
Mycoplasma pneumoniae
381
1,580
1,760
820
334
1,009
1,640
1,285
1,125
686
10,620
Mycoplasma hominis
2
4
-
2
-
2
-
2
5
8
25
Total
383
1,584
1,760
822
334
1,011
1,640
1,287
1,130
694
10,645


Mycoplasma pneumoniae infections reported to LabVISE were most commonly reported in female children aged 5-9 years (male to female ratio 0.9:1, Figure 22).

Figure 22. Laboratory reports to LabVISE of Mycoplasma pneumoniae infections, 1991 to 2000, by age and sex

Figure 22. Laboratory reports to LabVISE of Mycoplasma pneumoniae infections, 1991 to 2000, by age and sex

Mycoplasma pneumoniae reports show variation from year to year without a distinct seasonal peak (Figure 23).

Figure 23. Laboratory reports to LabVISE of Mycoplasma pneumoniae infections, 1991 to 2000, by month of report

Figure 23. Laboratory reports to LabVISE of Mycoplasma pneumoniae infections, 1991 to 2000, by month of report

Mycoplasma hominis is commonly isolated from the genitourinary tract (more commonly from women than men), the neonatal conjunctiva and peripartum blood. The organism is associated with cervicitis, vaginitis, conjunctivitis and peripartum sepsis.45

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Rickettsia

Coxiella burnetii

The rickettsial pathogen Coxiella burnetii is the cause of an acute febrile disease with a variety of clinical presentations of variable severity and duration (Q fever). The disease is particularly associated with livestock workers. Notifications of Q fever to the NNDSS and laboratory reports of Coxiella burnetii to LabVISE between 1991 and 2000 are shown in Table 40.

Table 40. Laboratory reports to LabVISE and notifications to NNDSS of Coxiella burnetii infection (Q fever), 1991 to 2000

Surveillance system
1991 1992 1993 1994 1995 1996 1997 1998 1999 2000
LabVISE
240
270
552
345
167
208
259
137
221
101
NNDSS
595
543
889
664
466
554
580
560
518
573


The NNDSS case definition for Q fever46 is based on serology or isolation of the organism from a clinical sample. The trends in laboratory reports to LabVISE are similar to trends in NNDSS data, with a peak in reports in 1993 and lower reports in more recent years as a result of Q fever vaccine initiatives among abattoir workers, who are at high risk of contracting the disease.

An age, sex analysis of Coxiella burnetii infections shows a large male predominance (male:female ratio 5.2:1), similar to that shown in NNDSS data. The largest numbers of laboratory reports to LabVISE were from men aged 25-29 years (Figure 24).

Figure 24. Laboratory reports to LabVISE of Coxiella burnetii infections, 1991 to 2000, by age and sex

Figure 24. Laboratory reports to LabVISE of emCoxiella burnetii/em infections, 1991 to 2000, by age and sex

Small numbers of laboratory reports of other Rickettsia were sent to LabVISE during the period as shown in Appendix 3.

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Other pathogens

From 1992 to 1996 and in 1999 and 2000, several hundred reports were made to LabVISE of group A streptococci. While streptococcal group A infections have declined dramatically in Australia, Indigenous Australians in northern Australia continue to suffer endemic infection with corresponding high rates of rheumatic fever,47 acute post-streptococcal glomerulonephritis,48 streptococcal pyoderma49 and resulting chronic renal disease and rheumatic heart disease.

A significant number of reports to LabVISE during the period 1991 to 2000 were received for other pathogens under surveillance in the NNDSS (Appendix 2). These include isolations of Yersinia, Brucella, Bordetella, Legionella, Leptospira, Treponema and Echinococcus. Since data on these pathogens was collected sporadically over the period and represent only a small fraction of notified cases reported to NNDSS, no analysis has been attempted here. Similarly for small numbers of reports of Cryptococcus, Entamoeba histolytica and Toxoplasmosis gondii no meaningful comments can be offered.

The reader is referred to NNDSS annual reports published in Communicable Diseases Intelligence for detailed analysis of the epidemiology of these and other pathogens in Australia.


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

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