Infection models with animals whose immune systems have been selectively altered by neutralization of endogenous cytokines or by deletion of a gene have provided a valuable means to study the function of cells or cytokines in the context of complex multidimensional interactions. In particular, knockout mice have allowed a deeper insight into thein vivo performance of antifungal...
Phenotypic variability in pathogenic fungi has long been correlated with virulence, but specific genetic and molecular mechanisms are only recently being unraveled. Fungal morphogenesis, reflecting the expression of several regulated genes, and the capacity of the rising forms or phases to cause disease has been focused on at the XIVth Congress of the International Society for...
The presence of various pathogenic fungi in rather unsuspected hosts and environments has always attracted the attention of the scientific community. Reports on the putative role of animals in fungal infections of humans bear important consequences on public health as well as on the understanding of fungal ecology. Fungi are ubiquitous in nature and their great capacity for...
The natural fungal pathogens of laboratory animals such as rabbits and guinea pigs are mainly dermatophyte species, most commonly Trichophyton mentagrophytes and also, less frequently Microsporum gypseum and M. canis. However, the incidences of infection and clinical disease are low in well-managed animal facilities. Young or immunocompromised rabbits are thought to be most...
The mycoses selected for presentation in this section are relatively common diseases of companion animals or livestock in certain areas of the world. Malasseziosis is arguably the most frequent mycosis of dogs (as otitis externa and dermatitis) throughout the world, although its diagnosis is often overlooked. Protothecosis is also geographically widespread, particularly in cattle...
Mycotoxins and the fungi that produce them are of increasing importance as causes of human illness, but the diseases produced remain poorly understood at the clinical level. This paper explores four aspects: the increase of interest in ochratoxin A, factors affecting mycotoxin production, toxicology of the major mycotoxins, and the identification of Penicillium species which...
Although there has over recent years been a marked rise in the incidence of serious fungal infections, many of which are prevalent in developing countries, few facilities exist for diagnosis and research in medical mycology. In most countries, medical mycology is not taught adequately to medical students and consequently there is little awareness of the importance of fungal...
Growth of commonly occurring filamentous fungi in foods may result in production of mycotoxins, which can cause a variety of ill effects in humans, from allergic responses to immunosuppression and cancer. According to experts, five kinds of mycotoxins are important in human health around the world: aflatoxins, ochratoxin A, fumonisins, certain trichothecenes, and zearalenone...
The start of Latin America's love story with fungi may be placed in pre-Hispanic times when the use of fungi in both ritual ceremonies and daily life were common to the native civilizations. But the medical mycology discipline in Latin America started at the end of the 19th Century. At that time, scholars such as A. Posadas, R. Seeber, A. Lutz and P. Almeida, discovered agents of...
A case of cryptococcosis in a dog is reported. The titers of polysaccharide antigen in sera were monitored by latex agglutination (LA) tests during and after treatment with antifungal therapy. Although the LA titers decreased in response to therapy, it took about 3·5 years to achieve a negative LA test. To model the persistence of cryptococcal polysaccharides, we examined the...
The results of 5034 blood cultures, implementing a lysis-centrifugation method with saponin, are summarized in this paper. Three hundred and twenty two blood samples (6·3%) obtained from a pool of human immunodeficiency virus (HIV)-positive patients yielded fungi. Cryptococcus neoformans was isolated in 199 samples (3·95%), Histoplasma capsulatum in 95 (1·89%). Candida...
Phagocytic cells play an important role in nonspecific resistance to fungal infection by mediating an inflammatory response and by a direct fungicidal action. In this study, the functional activity of peritoneal macrophages obtained from hamsters experimentally infected with strain Pb18 of Paracoccidioides brasiliensis was evaluated during 16 weeks of infection. The results...
The in vitro responses of peripheral blood mononuclear cells (PBMC) from healthy immune and non-immune donors were assessed by flow cytometry after incubation with the coccidioidal antigen toluene spherule lysate (TSL). After 120 h of incubation with 100 µg ml-1 of TSL, expression of the activation markers CD69, CD25 and human leukocyte antigen-DR were all significantly increased...
Optical brighteners of the diaminostilbene type are fluorescent dyes which are popular diagnostic tools in the mycology laboratory. While these dyes are conventionally used for the in vitro diagnosis of mycoses, their low toxicity and chemical reactivity have led us to investigate their potential use for in vivo staining of fungal elements in mycotic tissue. In mice we have...
In these studies, we compare the efficacy of two new azole antifungals with fluconazole in a murine model of cryptococcal meningitis. Mice were infected intracranially. Beginning one day later, groups of 7–10 mice were treated through to day 10 orally with UR-9751 or UR-9746 at 0·1, 0·25, 0·5, 1 or 10 mg kg−1 day−1 or fluconazole at 10 mg kg−1 day−1. At 10 mg kg−1 day−1, all...
Mucosal candidosis is common in acquired immune deficiency syndrome (AIDS) patients, where there is extensive mucosal involvement, but rarely dissemination. To mimic this disease, SCID mice were inoculated orally with Candida albicans, which could be recovered from standardized tissue samples of the esophagus, stomach, small intestine and caecum of all mice. Treatment with...
Voriconazole is a broad spectrum, triazole antifungal drug now well into the final phases of clinical trials in humans. During preclinical phases of development, it was found that when administered to mice, one of the more important animals used in the in vivo evaluation of antifungal compounds, serum voriconazole concentrations were very low at best and often undetectable. This...
High (H) and low (L) responder mice were selected for their ability to produce antibodies against sheep and human erythrocytes (Selection IV-A). In this selection, the difference in antibody responsiveness between H and L lines (HIV-A and LIV-A mice, respectively) was shown to depend mainly on macrophage function. The more rapid catabolism of antigens by macrophages in L mice has...
Despite promising pharmacodynamic and pharmacokinetic profiles, modern antifungals exhibit limited efficacy in the treatment of onychomycoses. The clinical and mycological data are far from reaching a complete cure even after long-course treatments extending over many months. After reviewing the histological presentation of onychomycoses, one of the main reasons for treatment...
We studied the correlation among cellular immune response, the pattern of lung granulomatous lesions and alterations in spleen lymphoid structure in Swiss mice inoculated intravenously with Paracoccidioides brasiliensis strain 18. The animals were evaluated at 24, 48 and 96 h after infection and further studied weekly for 18 weeks by: (i) the macrophage migration inhibition test...
Dermatophyte species are common keratinophilic fungi responsible for superficial infections called dermatophytosis or ringworm and composed of three anamorphic genera, Trichophyton, Microsporum and Epidermophyton. Through the use of several complementary molecular methods, dermatophytes have been shown to constitute an homogeneous group of species with very low genetic diversity...
Host defense mechanisms against vaginal Candida albicans infections are poorly understood. Despite the protective role of T helper (Th)1-type cell-mediated immunity (CMI) against mucosal C. albicans infections, studies using an estrogen-dependent murine model of vaginal candidiasis have shown a lack of effect of systemic Th1-type CMI against a vaginal C. albicans infection, and a...
A hexadecyltrimethylammonium bromide (CTAB) method for isolating fungal DNA from clinical samples, suitable for PCR amplification is described. Yeast and filamentous fungi DNA from clinical samples was amplified with primers complementary to the genescoding for rRNA, amplifying a 105 bp fragment and internal transcribed spacer primers amplifying fragments between 242 and 622 bp...