Detection ofHistoplasma capsulatumDNA in peripheral blood from a patient with ocular histoplasmosis syndrome (original) (raw)
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Histoplasmosis: An Important Mycosis of Public Health Significance
Histoplasmosis, a highly infectious fungal disease of public health concern, is caused by Histoplasma capsulatum var. capsulatum, a dimorphic fungus that occurs in mycelial and yeast form. The respiratory tract is recognized as the primary site of H. capsulatum var.capsulatum and the infection is acquired by inhalation of fungal spores from the saprobic environment. Disease can occur in sporadic as well as in epidemic form causing morbidity and mortality in susceptible individuals. Sporadic cases of histoplasmosis are reported from over 60 countries of the world including India. In USA, 25,000 cases of histoplasmosis are diagnosed every year. Certain groups of people who are associated with the soil related activities are at greater risk for developing the severe forms of disease. The fungus has the potential to infect every organ of the body including the skin, lung, brain, eye, adrenal gland, heart, liver, spleen, nose, gastrointestinal tract etc. The infection remains asymptomatic in over 90% of cases. The clinical presentation is varied and the affected person shows fever, headache, dry cough, dyspnea, chest pain, profuse sweating, lymphadenopathy, lesions in the mouth and skin etc. histoplasmosis in immune compromised patients, especially suffering from AIDS has poor prognosis. Mycological, immunological, and molecular techniques are employed to confirm an unequivocal diagnosis of disease. However, the isolation of H. capsulatum var. capsulatum from the clinical specimens still considered the gold standard of diagnosis. Antifungal drugs like liposomal amphotericin B and itraconazole are recommended for the management of disease. The disseminated histoplasmosis can be fatal if left untreated. It is imperative that immune compromised persons must avoid visiting the heavily contaminated sites that are inhabited by bats excreta and avian droppings.
Brazilian Journal of Microbiology, 2006
Endemic mycoses can be challenging to diagnose and accurate interpretation of laboratory data is important to ensure the most appropriate treatment for the patients. Although the definitive diagnosis of histoplasmosis (HP), one of the most frequent endemic mycoses in the world, is achieved by direct diagnosis performed by micro and/or macroscopic observation of Histoplasma capsulatum (H. capsulatum), serologic evidence of this fungal infection is important since the isolation of the etiologic agents is time-consuming and insensitive. A variety of immunoassays have been used to detect specific antibodies to H. capsulatum. The most applied technique for antibody detection is immunodiffusion with sensitivity between 70 to 100 % and specificity of 100%, depending on the clinical form. The complement fixation (CF) test, a methodology extensively used on the past, is less specific (60 to 90%). Detecting fungal antigens by immunoassays is valuable in immunocompromised individuals where such assays achieve positive predictive values of 96-98%. Most current tests in diagnostic laboratories still utilize unpurified antigenic complexes from either whole fungal cells or their culture filtrates. Emphasis has shifted, however, to clinical immunoassays using highly purified and well-characterized antigens including recombinant antigens. In this paper, we review the current conventional diagnostic tools, such as complement fixation and immunodiffusion, outline the development of novel diagnostic reagents and methods, and discuss their relative merits and disadvantages to the immunodiagnostic of this mycosis.
Infectious sources of Histoplasmosis and molecular techniques for its identification
Nepal Journal of Biotechnology
Histoplasmosis, a fungal infection caused by Histoplasma capsulatum (H. capsulatum), acquired from contaminated soil with droppings of chicken or birds and found to be distributed in many parts of the world. The prevalence of histoplasmosis has not well studied in Nepal. The common symptoms of acute and epidemic histoplasmosis include high fever, cough, and asthenia and weight loss. Most of the infections associated with histoplasmosis are asymptomatic. People with compromised immune systems such as HIV/AIDS (PLWHA), cancer, and organ transplant recipients are at risk of developing this disease. In this review, we have summarised the current status of histoplasmosis in Nepal and molecular techniques available for its identification. To date, the significant outbreak is not reported in Nepal, but the risk of infection for the vulnerable population cannot be undermined. Appropriate preventive measures and treatment on time can reduce the burden of this fungal disease. Further, this re...
Disseminated histoplasmosis in an HIV-infected patient discovered by routine blood smear staining
European Journal of Clinical Microbiology & Infectious Diseases, 2005
Histoplasma capsulatum is a dimorphic fungus of the Ascomycetes class. Histoplasmosis is the most common endemic mycosis in the USA and has emerged as an important opportunistic infection among patients with HIV living in or visiting endemic areas [1]. While the illness is subclinical or presents as a mild self-limited pulmonary infection in healthy individuals, the majority of cases involving AIDS patients show signs of a life-threatening disseminated infection. Presented here is a case of disseminated histoplasmosis in an HIV-infected patient living in Switzerland, which was diagnosed by examination of a simple blood smear. A 45-year-old man was referred to our hospital in 2003 with a 3-week history of fever, cough, shortness of breath and fatigue, a 3-month history of diarrhea (3-4 times a day), and a 5-kg weight loss. The patient had been diagnosed with HIV 5 years previously but had refused treatment. Originally from Colombia, he had resided in Switzerland since 1979. Three months before hospital admission, he had visited his native country. At the time of hospitalization, the patient was tachycardic and tachypneic, with a temperature of 39.6 • C. Bilateral pulmonary rales and hepatosplenomegaly were noted. The abnormal laboratory findings were as follows: hemoglobin 7.9 g/dl, leukocyte count 9.9 G/l with left deviation of 36% and lymphopenia 6%
Epidemiology of Histoplasmosis
Infectious diseases, 2023
More prevalent than initially considered, histoplasmosis is primarily a non-contagious disease of the reticuloendothelial system, producing a broad spectrum of clinical manifestations, ranging from asymptomatic or self-limited infection, in immunocompetent patients to life-threatening, disseminated disease in immunocompromised ones. The causative agent is H. capsulatum, a thermally dimorphic, intracellular fungus, discovered in 1906, by the pathologist Samuel Darling, when examined tissues from a young man whose death was mistakenly attributed to miliary tuberculosis. Since then, histoplasmosis was described on six continents, with high and low endemicity areas. H. capsulatum is a soil-based fungus, commonly associated with river valleys in the temperate zone, and with the presence of bird and bat guano. Infection occurs when saprophytic spores are inhaled and change to the pathogenic yeast in the lungs, where H. capsulatum overcomes many obstacles to cause host injuries. Depending on geographic distribution, morphology, and clinical symptoms, three varieties have been historically recognized, two of them (var. capsulatum and var. duboisii) being pathogen to humans, and the third (var. farciminosum) has predominantly been described as an equine pathogen. In endemic areas, patients with AIDS or people who receive immunosuppressive therapies should be counseled to avoid high-risk activities; otherwise, precautionary measures should be taken.
Emerging Infectious Diseases, 2007
African histoplasmosis caused by Histoplasma capsulatum var. duboisii is an invasive fungal infection endemic in central and west Africa. Most of its ecology and pathogenesis remain unknown. H. capsulatum var. capsulatum is an AIDS-defi ning opportunistic infection in HIV-infected patients who are living in or have traveled to histoplasmosis-endemic areas. In contrast, reports concerning African histoplasmosis during HIV infection are rare, although both pathogens coexist in those regions. We report 3 cases of imported African histoplasmosis diagnosed in France in HIVinfected patients and a literature review on similar cases.
Actas Dermo-Sifiliográficas, 2018
Histoplasmosis is a systemic mycosis caused by the dimorphous fungus Histoplasma capsulatum (H. capsulatum). The fungus enters the body through the respiratory tract in the form of microconidia, which are transformed into intracellular yeast-like structures in the lungs before disseminating hematogenously. Primary infection is usually asymptomatic and selfresolving. Some patients develop severe disease with acute or chronic respiratory involvement. Immunosuppressed patients, mainly those with altered cellular immunity, may have disseminated disease with variable mucocutaneous involvement characterized by papules, nodules, gummas, or ulcers with a granulomatous base. We report the case of 3 HIV-negative patients infected by H capsulatum in whom diagnosis based on the skin lesions proved essential for early initiation of treatment.
Rapid PCR-Based Diagnosis of Disseminated Histoplasmosis in an AIDS Patient
European Journal of Clinical Microbiology & Infectious Diseases, 2002
Disseminated histoplasmosis is an unusual opportunistic infection in patients with advanced HIV infection living outside endemic areas. Diagnosis usually is made on the basis of isolation of Histoplasma capsulatum from clinical specimens or histologic examination. Reported is the case of an HIV-infected Columbian individual in whom the diagnosis of histoplasmosis was established within 24 h of collection of an adequate bronchoalveolar lavage specimen. The diagnosis was made by detection of specific fungal DNA and confirmed by isolation of Histoplasma capsulatum from blood, bone marrow and respiratory specimens 10 days later. The patient recovered under antifungal treatment and remained asymptomatic up to the last follow-up visit 6 months later. The polymerase chain reaction assay might be a powerful and rapid diagnostic tool for the diagnosis of non-European invasive fungal infections and should be further evaluated.