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For multiple reasons, the emergent infectious risks do not stop increasing these last twenty years. The climatic modifications and the human interventions modifying the biotope as well as the rapid spreading of resistant strains to treatments, generate re-emergence or emergence, all the more dramatic as the means of fight are reduced. These emergent or re-emergent diseases are extremely worrisome as their diagnosis and their prevention are often difficult. The important infesting power of parasites and the particularly effective capacities of adaptation of these eucaryotes contributed to the public health problems. Anthropozoonoses and zoonoses constitute a permanent risk the control of which is imaginary. The new pathogenic agents, the unusual clinical demonstrations in the context of deficiency of the host immune functions imply attentiveness and a permanent up to date of the knowledge of the biologist and of the different professionals of health. The risks with which are confronted the humanity during this century underline the necessity of determining mechanisms involved in the pathogenesis. The determination of the specific and vital biologic processes for the microorganism, could allow to define the most appropriated targets and the most effective and original means of fight.

A LEADING CAUSE OF MORTALITY: Inhalation of fungal spores may cause infection and/or inflammation, which is dependent on the nature of the fungus as well as the individual's immune status. Aspergillus fumigatus is responsible for a dramatic pathology, invasive aspergillosis (IA). IA has become a leading cause of death, mainly among bone marrow transplantation or solid-organ recipients, but also among AIDS patients. IMMUNE RESPONSE: The diversity of immune failure suggests that many lines of immunity are implicated in the A. fumigatus elimination process. Non specific immunity plays a major role in the defence against A. fumigatus, including three major lines: anatomical barriers, humoral components, phagocytic cells. But acquired immunity plays a role with different T-cell subsets and their associated cytokines. FUNGUS-HOST RELATIONSHIPS: The relationship between the fungus and its host is complex and could be again study to improve the prevention and the treatment of IA. The aim of this review is a synthesis of the knowledge about the immunity response against Aspergillus fumigatus in IA.

The biological diagnosis of malaria is urgent to avoid rapid and fatal outcome. Every year in France, 5,000 imported malaria cases are observed. Thin stained blood smear microscopical examination remains the reference method of diagnosis; however its performance is linked to the professional competence of the biologists. Thus easier methods have been developed (QBC test). Some of them, limited to the diagnosis of malaria due to Plasmodium falciparum do not require highly skilled personal to perform or interpret (antigen detection on dipsticks, tests Parasight or cardboard, ICT Malaria Pf), but limitations and errors occurred. These different tests must be complementary methods of traditional diagnosis. In association with microscopical examinations, they provide rapid and efficient diagnosis of malaria in non-endemic areas. Relying on our experience, the best association is: QBC + thin blood smear and depending of results antigen detection (ParaSight F, ICT Malaria Pf).

Twenty-two candidemia happened in our hospital from January 1997 to may 1998. We studied the clinical evolution of the patients and the sensitivity of the yeasts to antifungal therapy (Fungitest and E-Test method). We found 11 Candida albicans (CA), 10 Candida non albicans (CNA) (3 C. glabrata, 2 C. parapsilosis, 4 C. tropicalis, 1 C. krusei) and 1 Saccharomyces cerevisiae. The mean age of the patients was 56.4 years. There were 13 men and 9 women. We found one group of 8 (36.4%) oncohematological patients, one group of 8 (36.4%) patients with abdominal surgery, one group of 3 (13.6%) children and one group of 3 adults (13.6%) who spent more than 10 days in an intensive care unit. Ten times, these candidemia were associated with bacteriemia, 4 times with several bacteria. Three patients died because of the candidemia, 2 times with CNA and one time with CA. There wasn't any resistance to amphotericin B or ketoconazole. All the CA and 3 CNA (30%) remained sensitive to the four antifungal drugs we used (amphotericin B, ketoconazole, fluconazole, itraconazole). The 3 C. glabrata and the C. krusei were resistant or limit to fluconazole. Since the generalization of the use of fluconazole, the epidemiology is marked by the emergence of new strains of CA with high level of resistance to azols, and of CNA. In our hospital, the CA remain preponderant and only the CNA are resistant to fluconazole making difficult the choice of empiric treatment for serious fungemia.

Due to the increase of opportunistic mycosis and parasitosis for several years, the management of fungal and parasitic risk in hospital has become a necessity and an obligation. The authors remind the main rules and knowledges essential to an optimal management of the fungal and parasitic disinfection in hospital. They summarize the efficiency of different disinfection processes in relation to yeasts, filamentous fungi, Pneumocystis carinii, Cryptosporidia and Microsporidia involved in hospital pathology.

During the last two decades, deep changes have arised in aspergillosis. Thus, this fungal infection mainly due Aspergillus fumigatus is becoming a serious public health-hazard in the growing population of immunocompromised patients. From literature and their own experience, the authors present a synthesis of phenomenons promoting this evolution: the host predisposing factors, environment and potential contamination sources, then the fungus itself. Genetic research developed into the disease-causing organism could be of major interest in epidemiology of aspergillosis and to identify new targets of prophylaxis.

Opportunistic parasitosis and mycosis are becoming ever more widespread, mainly under the influence of major immunodeficiencies, either acquired (AIDS) or therapeutic. In this general overview, their main aspects, both clinical and epidemiological, are underlined. In terms of epidemiology, three types of phenomena have been observed: 1) emergence of human parasitosis unknown before (microsporidiosis due to Enterocytozoon bieneusi, Encephalitozoom hellem or Septata intestinalis); 2) among the human parasites already known, identification of very pathogenic strains (Toxoplasma gondii, Aspergillus fumigatus, Cryptococcus neoformans); 3) origin probably or certainly nosocomial of certain infections (pneumocystosis; toxoplasmosis and visceral leishmaniasis transmitted during bone-marrow or organ transplantations). The development of deep mycosis (invasive aspergillosis) is particularly promoted by granulopenia and alterations in the phagocytosis. On the other hand, opportunistic protozoosis (toxoplasmosis and leishmaniasis) and helminthiasis (strongyloidosis due to Strongyloides stercolaris) are related, above all, to disorders in cellular immunity (deficit of CD4+, mainly). Finally, several of these infections may be characterised by a variety of clinical pictures and outcome, depending on the contributory factors (immunodeficit or not) which led to the development of the infection.

Establishing the diagnosis of invasive aspergillosis consists primarily in the detection of Aspergillus hyphae, the invading form of the fungus, mainly from respiratory tract specimens and by cultural isolation. In this overview of the topic, we emphasise the major obstacles to the successful diagnosis of this fungal infection. The authors describe then the general procedures for histopathological and mycological diagnosis (samples, choice of method and the interpretation of results). Finally, they summarise, from literature the success rate in detecting Aspergillus, depending on the potentially infected sites and the specimens examined (broncho-pulmonary or extra-pulmonary).

In sterile hospital units filamentous fungal infections are an unacceptable risk in patients with prolonged agranulocytosis. The occurrence of 3 successive cases in the Sterile unit of University Hospital of Grenoble prompted us to investigate in all elements of sterile unit, and notably food-processing. Two cooked rice dishes given to these patients were found to contain a substantial amount of Aspergillus fumigatus and were probably responsible for these infections. A more detailed study was carried out to evaluate the degree of food contamination by fungi in sterile unit. The study included 97 cooked dishes which had been sterilized in a 250 degrees oven for 40 minutes and 176 industrially packed foods delivered in single packs (e.g. milk and its derivatives, sweets and drinks). Each foodstuff was mycologically examined 3 to 5 times in different packs according to a procedure used in food analysis laboratories and raised to the standards of mycological examination. In this way, a 3-monthly food testing protocol in sterile unit could be set up. This protocol has a dual purpose: regular checking of the cooked dishes chain and maximum diversification of the dishes.

Rapid identification of Candida albicans is of great importance as it is the most frequently isolated yeast pathogen. Rapidec albicans, a new 2-h micromethod, performs two fluorescent enzymatic activities: hexosaminidase and proline arylamidase. A total of 444 yeast strains (334 from type culture collections and 110 from recent clinical isolates) were tested. The sensitivity was 98.5% and the specificity 95.8%. When only considering the clinical strains, 47/47 Candida albicans were identified by Rapidec albicans (sensitivity 100%) but only 43/47 by the germ tube test (sensitivity 91.5%). The specificities of the two tests were respectively 98.2% and 100%. This new system is therefore very efficient for the routine diagnosis of Candida albicans in the clinical field. It is easier and quicker than the germ tube test.

Multiple intracerebral aspergillus abscesses in a 5 year old boy with a Burkitt's lymphoma are described. The disease was fatal despite antifungal treatment. The diagnostic and therapeutic problems, the risk factors and preventive care are discussed.

We had the opportunity of studying an epidemic of autochthonous amoebiasis occurring in the autumn of 1974 in a small town of 4000 inhabitants 30 km from Grenoble. Attention was originally attracted by the occurrence in this town of two cases of hepatic amoebiasis and one of intestinal amoebiasis identified by rectoscopy. Systematic investigations (coproctic examinations and serological tests for amoebiasis by indirect antibody fluorescence) were then carried out on everyone in the locality with digestive disorders which were possibly referable to amoebiasis, and on the other members of their families. A total number of 148 coproctic examinations were made and in two cases revealed the presence of vegetative forms of Entamoeba histolytica. In both cases the infestation provoked few symptoms (asthenia, vague abdominal discomfort, intermittent and apparently banal diarrhoea). On the other hand 20 out of 94 serological tests revealed positive results, 14 of which were equal to or greater than a titre of 1/100, a level at which all risks of non-specificity are virtually ruled out under our experimental conditions. Material reasons made it impossible to subject these cases to repeated faecal checks, but in two of them at least the rectoscopic appearances were very suggestive of subacute intestinal amoebiasis. Moreover, amoebic disease appears to be well confirmed by the results obtained among the patients as a whole by treatment with Metroinidazole. A variety of hypotheses on the origin of this epidemic have been put forward and then abandoned (market garden produce, receipt by certain families of exotic frut from overseas). In actual fact water seems to be the point of departure, for, although specimens of water taken at 7 different levels in the water supply system failed to reveal the presence of a single amoeba, bacteriological analyses during autumn 1974 showed signs of faecal contamination. The locality, which is situated at the foot of the Chartreuse massif, receives its water solely from springs but there is a holiday camp for the staff of an international airline situated above the main water catchment.

The study of the experimental pathogenic effect on the mouse of 47 strains of free-living amoebas (Vahlkampfia, Naegleria, Hartmannella and Acanthamoeba) showed that 5 strains belonging all to the species A. polyphaga could induce a fatal meningo-encephalitis in the mouse. After axenisation of 12 strains of Acanthamoeba, the study of the cytopathogenic effect in vitro showed that all the strains studied were able to induce, sooner or later, the destruction of the cellular layer. But, using the same inoculum, the strains pathogenic for the animal, seemed to have a quicker cytopathogenic effect in vitro.

An epidemiological study concerning the search for and identification of free-living amoebae has been carried out on swimming pool water in the Grenoble area. Eleven establishments were surveyed over a period of one year, by taking samples of water every month. The results obtained show that the positive nature of the samples and the nature of the isolated species are influenced by the two factors being studied: The rhythm of the "Summer-Winter" use of swimming pools and the nature of the sterilising procedure, chlorine, bromine and ozone. The current sterilising conditions of the swimming pool water are discussed.

Identification and in vitro susceptibility testing of fungi is necessary mainly in immunocompromised patients. So, after a survey of the epidemiological results, the authors specified the indications of susceptibility tests; their advantages and difficulties and the lots of variations related to the fungus, drug, medium and technic. The authors compared the more recent methods from their experience: susceptibility to 6 antifungals (amphotericin B, flucytosine and 4 imidazoles) was estimated in 122 yeast strains isolated from deep specimens by 5 marketed technics. They got a good correlation between Mycototal and Antifongigramme Pasteur, but the two other technics (Mycodisk and Neosensitabs) frequently showed unreliable results.

This study took place between February 1984 and February 1985 in 76 febrile neutropenic patients. We evaluated the whole mycological and serological results, in 91 febrile episodes. We separated two groups: group I (acute leukemia, chronic myeloïd leukemia, medullar aplasia, lymphomas) and group II (chronic lymphoïd leukemia, Hodgkin disease, myelomas, solid tumors). Patients were included in this study if they developed a temperature of 38.5 degrees C or greater and if they had less than five hundred neutrophils per mm3. They were treated with mono or bi-antibiotherapy. If the patient remained febrile more than 72 hours, an antifungal therapy was added (Amphotericin B IV). Through these weekly results, we conclude: the high frequency of digestive tract candidiasis in such patients; disseminated candidiasis occurs only in the first group patients with fungal digestive colonization; the overall response rate in this study was 77 per cent. This underlines the interest of empiric treatment with amphotericin B IV.