Epidemiological Survey on Cryptococcosis

To investigate the incidence and the epidemiology of cryptococcosis in Europe and provide new insights into the distribution of the infecting strains over the continent, a prospective survey was started on July 1997 by the ECMM. Members in seventeen European countries participated in a collaborative prospective survey (Sept 1997- Dec 1999). Convenor of this study was Maria-Anna Viviani (Istituto di Igiene e Medicina Preventiva Università degli Studi di Milano, Italy).

In a 30 month period, 655 cases were notified and 565 were evaluable. Most of the cases were reported by 8 of the16 participating countries. Cryptococcosis was associated with HIV infection in 77% of patients (range 59 to 94% according to country) and was AIDS-defining in 57.5% (range 24–80%). Other predisposing factors, mainly cancer and organ transplantation, were reported in 18% of cases and risk factor was unknown or not reported in 5%. Cryptococcal infection was clearly underreported, also where an active reporting network was already present. The annual incidence could be estimated in an Italian region (Lombardia) where it was 0.85/100 AIDS population, a rate comparable to the incidence reported in the same period for the metropolitan Atlanta (USA). The fungus was grown in culture from 94.5% of the 542 culturally investigated patients and the high number of cases diagnosed on the basis of CSF-positive cultures (77%) suggested that late diagnosis was frequent. Treatment was started with amphotericin B in 50% of cases, combined with flucytosine in half of them, and fluconazole in 22%. Various combination therapies were used for the remaining patients.

The infecting isolate was identified as Cryptococcus neoformans var. neoformans in all cases with the exception of six cases caused by the gattii variety and four infected by other Cryptococcus species (C. albidus, laurentii and luteolus). All var. neoformans isolates, except those from France and UK, were serotyped by Crypto Check agglutination test and genotyped by PCR fingerprinting using (GACA)4 as single primer. This analysis provided interesting information on the value of the typing methods and on the distribution of var. neoformans serotypes and genotypes in Europe. PCR fingerprinting proved to be more reproducible and reliable than the serological method in identifying the serotype AD strains, hybrids from crossing of serotype A and D strains. Molecular methods were also essential for determining the mating type and identifying strains containing the Aa allele.This method brought to the discovery of a serotype A MATa strain, the third known in the world up-to-now (paper submitted).

The interim analysis of the first 30- month survey was presented orally at the 6th ECMM Congress in Barcelona in November 2000, and a paper is ready to be submitted. Posters were also presented by several coordinators reporting the data from their country, data now published in different journals (Mycoses 2001; 44:345-50 / Rev Iberoam Micol 2001; 18:99-104 / Medical Mycology 2002; 40:5507-17). Although the number of cases of cryptococcosis has been reduced by more than 50% by new antiretroviral therapies (HAART), continued monitoring of the cryptococcosis trend is essential to evaluate the effectiveness of HAART, to provide more data on the unusual manifestations of the “immune recovery syndrome” associated with the use of HAART, and to verify the possibility of safe discontinuation of suppressive therapy after sterilization of cultures and rise of CD4 cell count have been achieved. Finally, the molecular identification of the infecting strains will contribute to a better understanding of the dynamic evolution of C. neoformans. and the identification of genotypes with an altered virulence and/or resistance to antifungals. The aim of continuing monitoring is also i) to increase the number of reporting centres extending the network throughout Europe, ii) to develop diagnostic skills, iii) to raise awareness of cryptococcal infection also in non HIV-infected at risk patients, in whom cryptococcosis is often diagnosed too late or overlooked.
From Mycology Newsletter 2003, P. 6-7

List of publications:

• Viviani MA, Cogliati M, Esposto MC, Lemmer K, Tintelnot K, Valiente MFC, Swinne D, Velegraki A, Velho R. the European Confederation of Medical Mycology (ECMM) Cryptococcosis Working Group. Molecular analysis of 311 Cryptococcus neoformans isolates from a 30-month ECM survey of cryptococcosis in Europe. FEMS Yeast Research 2006; 6 (4): 614-619