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• Toxoplasma gondii infections diagnosed by the Toxoplasma Reference Unit (England and Wales, weeks 1-52/2009)

 

 

Toxoplasma gondii infections diagnosed by the Toxoplasma Reference Unit (England and Wales, weeks 1-52/2009)

The Health Protection Agency, in collaboration with the National Public Health Service for Wales (NPHSW), review the number of cases of Toxoplasma gondii infections diagnosed by the Toxoplasma Reference Unit (TRU) in Swansea [1]. This report summarises T. gondii infections diagnosed in 2009. Data for the first quarter of 2010 will be reported in the next Zoonoses quarterly report in the HPR.

Table 1. Toxoplasma gondii diagnoses by age group and status: weeks 1-52/2009

Age group	Status					Cumulative totals
	Acute	Cong-enital	HIV	Organ donor/ recipient	Not known	Weeks 1-52/2009	Weeks 1-52/2008
<0	–	–	–	–	–	–	5
<1	–	5	–	–	–	5	7
1-9	8	2	–	–	–	10	8
10-14	12	–	–	–	1	13	5
15-24	43	–	7	1	1	52	66
25-44	189	–	55	7	5	256	210
45-64	61	–	17	6	3	87	96
65-79	14	–	2	1	1	18	7
≥80	1	–	–	–	–	1	1
Not known	–	–	–	–	–	–	4
Weeks 1-52/2009	328	7	81	15	11	442	–
Weeks 1-52/2008	287	8	83	17	14	–	409

Table 1 describes the distribution of cases of T. gondii infection diagnosed by the TRU during 2009 by case status. A total of 442 T. gondii infections were confirmed in 2009 compared to 409 cases in 2008. Cases are classified by the TRU using specific laboratory and clinical diagnostic criteria [2, 3].

Of the 442 cases diagnosed in 2009, 328 (74%) were classed as acute cases of toxoplasmosis in immunocompetent individuals, seven were cases of congenital toxoplasmosis, 81 were in patients known to have HIV infection, and 15 were in organ donors or recipients.

During 2009 a total of 76 cases were reported by NHS laboratories to the HPA national surveillance system, compared with 65 in 2008, 95 in 2007 and 93 in 2006 [4, 5].

Table 2 describes the regional distribution of cases of T. gondii infection diagnosed by the TRU. As seen previously, the majority of cases were referred by laboratories in the London region (32%).

Table 2. T. gondii diagnoses by region, England and Wales

HPA Region	Cumulative totals
	Weeks 1-52/2009	Weeks 1-52/2008
East Midlands	10	7
East of England	45	38
London	141	179
North East	17	12
North West	37	30
South East	68	43
South West	66	37
Wales	12	8
West Midlands	24	23
Yorkshire and Humber	22	24
Unknown	–	8
Total	442	409

Of those cases diagnosed in 2009 for which information on gender was available (Table 3), the majority were in females (53%) of which 62% were aged 25-44 and of these 22% were pregnant women. A total of 36 pregnant women (aged 19-44) were diagnosed; six were mothers of congenitally affected babies. Males comprised 46% of cases diagnosed, with a majority (52%) aged 25-44. A similar age sex distribution was seen in 2008. The 25-44 age group comprised 58% of cases diagnosed by the TRU during 2009 compared to 51% in 2008.

Table 3. T. gondii diagnoses by age and sex in 2009

Age group	Female	Male	Unknown	Cumulative totals
				Weeks 1-52/2009	Weeks 1-52/2008
<0	–	–	–	–	5
<1	3	2	–	5	7
1-9	6	4	–	10	8
10-14	2	12	–	14	5
15-24	20	31	1	52	66
25-44	143	102	10	255	210
45-64	51	35	1	87	96
65-79	6	11	1	18	7
>80	1	–	–	1	1
Not known	–	–	–	–	4
Totals 2009	232	197	13	442	–
Totals 2008	206	166	5	–	409

For cases classed as acute, the symptoms associated with T. gondii infection and reasons given for testing on the laboratory request form are varied. In 2009 the principal reported symptoms/reasons were lymphadenopathy (58%), ocular (15%), pregnancy (10%), with no reason provided for another 10%.

Patients with HIV infection are often screened for T. gondii infection in the absence of clinical signs of toxoplasmosis, as reactivation of latent T. gondii infection can cause severe disease in immunocompromised individuals.

Toxoplasmosis is increasingly recognised as an important zoonosis in European countries. In England and Wales numbers of cases diagnosed by TRU are substantially greater than the numbers reported to the national surveillance system. These findings underline the importance of this current enhanced surveillance system in supporting national risk assessment initiatives. The data show a stable trend in the numbers of T. gondii cases diagnosed.

References
1. National Public Health Service for Wales website. Toxoplasma Reference Unit. Available at: http://www.wales.nhs.uk/sites3/page.cfm?orgId=457&pid=25359.

2. Health Protection Agency. Investigation of toxoplasma infection in pregnancy. National Standard Method QSOP 59 Issue 1, 2006. Available at: http://www.hpa-standardmethods.org.uk/documents/qsop/pdf/qsop59.pdf.

3. Health Protection Agency. Toxoplasmosis: Information for health professionals. Available at: http://www.hpa.org.uk/webw/HPAweb&HPAwebStandard/HPAweb_C/1195733799638?p=1191942176127

4. Health Protection Agency. Common animal associated infections, England and Wales laboratory reports: weeks 27-39/2009. Health Protection Report 3(49), 11 December 2009. Available at: http://www.hpa.org.uk/hpr/archives/2009/hpr4909.pdf.

5. Health Protection Agency. Toxoplasma gondii infections diagnosed by the Toxoplasma Reference Unit, England and Wales: weeks 40-52/08. Health Protection Report 3(6) 13 February 2009. Available at: http://www.hpa.org.uk/hpr/infections/zoonoses.