The general aim of the National Reference Centre (CNR) for Toxoplasmosis is to respond to the needs expressed by health professionals, clinicians and biologists in terms of epidemiology and diagnosing toxoplasmosis in all its forms, along with supporting studies on treating and preventing congenital toxoplasmosis and toxoplasmosis in immunosuppressed patients.
- Missions contributing to monitoring:
When the CNR was created in 2006, one of the main objectives was to help evaluate the pertinence of the national prevention programme for the disease that has been in place in France since 1978. To that end, the InVS (National Health Monitoring Institute), along with the Epidemiology Pole of the CNR, proposed the establishment of a national monitoring system for congenital toxoplasmosis based on case notifications. This monitoring system was initiated in 2006 and has collected data from congenital toxoplasmosis cases in France since 2007.
One of the CNR’s objectives is to better understand the epidemiology of toxoplasmosis strains in metropolitan France and the overseas departments and territories (‘DOM-TOM’) and studying the biodiversity of T. gondii. To that end, the Strains Pole has been given the mission of collecting strains from clinical samples, characterizing them (clinically and genotyping), comparing them to strains circulating worldwide and, where necessary, alerting health monitoring authorities of the occurrence of these grouped cases due to identical or similar genotypes. Thanks to close collaboration with the National Reference Laboratory (LNR) ‘Parasites transmitted through food’ (AFFSA-LERPAZ), the CNR also carries out comparisons of human strains with those isolated in the environment (particularly strains isolated from animals implicated in transmitting the disease).
A Toxoplasma Biological Resources Centre (CRB) has been integrated in the CNR for Toxoplasmosis, in partnership with the Epidemiology and Strains Poles (including strains collected in the framework of the CNR in the CRB). With the Epidemiological Pole, the CRB contributes to studying the circulation of toxoplasmosis in humans and animals (especially for better identifying the sources of human infection).
Another objective of the CNR is to better identify the sources of toxoplasmosis transmission; currently we observe an absence of knowledge on the respective weight of the mode of transmission in cases of toxoplasma infection. No diagnostic method can make the distinction in foodborne contamination between that which is due to meat consumption (infection by cysts) and that which is due to vegetable consumption (infection by oocysts), or even the risk of waterborne infection (only the data of waterborne infections have been reported in the library). In 2009, an ANR (National Agency for Research) research programme (ALIA Programme, Protofood) was obtained to establish parasite detection techniques (Cryptosporidium, Giardia, Toxoplasma) within various food matrices. It is carried out by various CNR member laboratories under the responsibility of the Coordinating Laboratory.
- Alert missions:
The Reference Centres must transmit to the InVS and the DGS (Directorate General for Health) the identification of grouped cases of the illness; for this, centralizing data is necessary. The CNR participates within a national framework of network laboratories, establishing a summary of toxoplasmosis cases in collaboration with the InVS. Research in specific epidemiological conditions and toxoplasma strains that are genetically different from usual strains (and that are known to be associated with severe illnesses) all contribute to this alert mission.
- Advising mission:
It must be carried out by health professionals, particularly for better screening and updated prevention advice about transmission, diagnostic advice and treatment. A good practices guide is currently being drafted by the Serology Pole to ensure immunological diagnosis in the best conditions; it is destined mainly for private laboratories or general hospitals that consult university hospitals in cases of difficulties in interpretation or dating an infection, particularly in pregnant women. A good practices guide will also be drafted by the Molecular Biology Pole for laboratories that diagnose the disease with PCR, particularly for antenatal diagnosis of congenital toxoplasmosis.