Lipids of Histoplasma Capsulatum
Rajendra Prasad, Mahmoud A. Ghannoum in Lipids of Pathogenic Fungi, 2017
Histoplasmosis is initiated by the inhalation of a sufficient quantity of spores or conidia. The primary site of infection is lungs.2 In its pathology, histoplasmosis resembles tuberculosis, which is caused by Mycobacterium tuberculosis. Studies in the 1950’s on the pathology of tuberculosis focused on a lipid-like component which was isolated from the organism and was toxic to certain strains of mice.8 This factor was called “cord factor” and was found to be trehalose-6,6’-dimycolate.9 This suggested that lipid associated with the bacilli could be involved in the pathogenicity of the organism. Due to its similarity to tuberculosis, an analysis of the lipids of both phases of H. capsulatum was undertaken in an effort to determine what role such compounds could play in the pathogenicity or in the dimorphism of the organism. This chapter will present our current knowledge of the lipids of H. capsulatum, with emphasis on novel phosphoinositol SPH isolated from the yeast phase which reacted with sera from patients with histoplasmosis.
Cutaneous Manifestations of Deep Fungal Infections in HIV Disease
Clay J. Cockerell, Antoanella Calame in Cutaneous Manifestations of HIV Disease, 2012
Histoplasmosis has a broad spectrum of clinical presentations, including asymptomatic infection, acute or chronic pulmonary infection, mediastinal fibrosis, granulomas, and disseminated histoplasmosis. The clinical presentation of histoplasmosis is determined by the magnitude of exposure and the host’s immune status.42 Low level exposure frequently results in asymptomatic infection. In endemic regions, over half of the population has been infected with H. capsulatum and yet most remain asymptomatic. Occasionally, low level exposure results in symptomatic pulmonary histoplasmosis manifest as a subacute flu-like illness with fever, dry cough, and fatigue. In such instances, ensuing antigen-specific T-lymphocyte-mediated immunity and fungistatic macrophage activation lead to containment of the infection and resolution of symptoms within a 1–2 week period.39
Serodiagnosis: Antibody and Antigen Detection
Johan A. Maertens, Kieren A. Marr in Diagnosis of Fungal Infections, 2007
One way in which Histoplasma antigen detection tests might be made more specific is through the application of monoclonal antibodies. Gomez et al. (248) developed an inhibition ELISA that utilizes a murine monoclonal antibody that recognizes an apparently species-specific epitope on a 69 to 70 kDa antigen. The test had sensitivities for acute and chronic forms of histoplasmosis of 89% and 57%, respectively. The specificity was 98% when normal human serum was tested and 85% when serum samples from individuals with chronic fungal or bacterial infections were tested. In contrast to the polyclonal sandwich ELISA, the monoclonal inhibition ELISA detected antigen more frequently in serum than in urine (248). More recently, Gomez et al. (249) used the inhibition ELISA to monitor the response to treatment of patients presenting with different clinical forms of histoplasmosis. Sera from four of five patients with acute pulmonary infection showed a rapid decline in antigenemia, becoming negative after 10 to 16 weeks. In non-AIDS patients with disseminated histoplasmosis, serum antigen levels declined with effective treatment, becoming undetectable in most patients. The effectiveness of the test in AIDS patients with disseminated histoplasmosis is less clear, with high levels of antigen persisting in most patients throughout treatment.
Zoonotic fungal diseases and animal ownership in Nigeria
Published in Alexandria Journal of Medicine, 2018
Adebowale I. Adebiyi, Daniel O. Oluwayelu
Histoplasmosis is an infection caused by Histoplasma capsulatum, a dimorphic fungus with two known varieties: H. capsulatum var. capsulatum and H. capsulatum var. duboisii. The two varieties have been identified in Africa. African histoplasmosis caused by H. capsulatum var. duboisii is a deep mycosis endemic in the African continent, essentially between the Tropics of Cancer and Capricon47,48 as well as in the island of Madagascar.49 It has been detected in about 20 countries in tropical Africa located between 20° North and 20° South of the Equator and extending from Senegal in the West to Tanzania in the East.47,48,50,51 This region is characterized by high average rainfall, high humidity and little variation in diurnal temperature.48
Acute histoplasmosis in travelers: a retrospective study in an Italian referral center for tropical diseases
Published in Pathogens and Global Health, 2020
Silvia Staffolani, Niccolò Riccardi, Claudio Farina, Giuliana Lo Cascio, Maurizio Gulletta, Federico Gobbi, Paola Rodari, Tamara Ursini, Giulia Bertoli, Niccolò Ronzoni, Zeno Bisoffi, Andrea Angheben
Histoplasmosis is acquired through the inhalation of microconidia. The disease is usually mild in immunocompetent people, who can be either asymptomatic or experience a self-limiting disease with aspecific symptoms that include fever, respiratory, gastrointestinal and rheumatologic symptoms, malaise and night sweats [22]. The disseminated disease is often fatal if not promptly recognized, particularly in patients with HIV infection (histoplamsosis is an AIDS-defining condition), stem cell or solid organ transplantation receivers [22,23]. Recently, histoplasmosis has raised increasing attention in immunocompetent travelers [24]. In fact, histoplasmosis is the most common endemic mycosis acquired by European travelers [12–14,25–29]. However, the index of suspicion is frequently low in non- endemic areas, hence misdiagnoses are possible [23]. The gold standard of histoplasmosis is culture from clinical specimens [30].
Spontaneous pneumothorax secondary to chronic cavitary pulmonary histoplasmosis
Published in Journal of Community Hospital Internal Medicine Perspectives, 2020
Samuel Geurkink, Leslie Cler
Acute pulmonary histoplasmosis is a syndrome typically characterized by relatively non-specific symptoms including fever, malaise, headache, and weakness, accompanied by a non-productive cough [3]. Substernal chest discomfort is occasionally a complaint as well. This presentation is common in individuals, particularly children, who are exposed to the organism for the first time. Hilar and mediastinal lymphadenopathy are often present, along with a patchy pneumonia on chest x-ray. A minority of patients present with erythema multiforme or erythema nodosum [3]. A more severe form of acute pulmonary histoplasmosis occurs in patient that are exposed to a large inoculum of the organism, or in those who are immunosuppressed. Patients with severe disease often develop respiratory failure and acute respiratory distress syndrome. While acute pneumonia due to Histoplasma is often mild and self-limiting, the severe form may require treatment with anti-fungal agents.