Histoplasmosis infection in Spanish travelers to Latin America

Pulmonary endemic mycoses

While rare, the likelihood of encountering a case of a pulmonary endemic mycosis (PEM) in the UK is increasing. Diagnosis may be challenging, often leading to considerable delay to appropriate treatment. Clinical suspicion must be present for respiratory disease, particularly in the immunocompromised or in those not responding to empiric treatment approaches, and an extended travel history should be obtained. This article summarises the epidemiology of PEM, key clinical features, diagnostic strategies and management.

Disseminated Histoplasmosis in an Indigenous Child With Malnutrition: A Case Report

Histoplasmosis is a mycosis caused by Histoplasma capsulatum, a dimorphic fungus endemic to areas with nitrogen-rich soil, like the one contaminated with bird and bat excrement. Patients with a deficient immune response are especially at risk for developing invasive infections, such as disseminated histoplasmosis, and secondary immunodeficiency can be a consequence of malnutrition. This case report presents a 15-month-old male infant with malnutrition who presented with signs and symptoms of disseminated histoplasmosis, including fever, malaise, weight loss, cough, and diarrhea. The infant came from a geographic area where histoplasmosis is endemic, and he was a member of a cultural group with a higher prevalence of histoplasmosis than the general population. On physical examination, hepatosplenomegaly, lymphadenopathy, and lung crackles were found, which are common in most patients with histoplasmosis. The keystone of diagnosis of H. capsulatum infection is antigen detection, but the criterion standard is isolation of the organism from body specimens through laboratory culture. Histological diagnosis is especially useful for rapid diagnosis. Treatment of disseminated histoplasmosis in the pediatric population consists of deoxycholate amphotericin B for four to six weeks followed by itraconazole to complete a total of three months of treatment. Despite the involvement of multiple organ systems, the patient recovered satisfactorily after the completion of amphotericin B treatment for one month and the resolution of his malnourishment.

Invasive and Subcutaneous Infections Caused by Filamentous Fungi: Report from a Portuguese Multicentric Surveillance Program

Invasive fungal infections (IFI) have significantly increased over the past years due to advances in medical care for the at-risk immunocompromised population. IFI are often difficult to diagnose and manage, and can be associated with substantial morbidity and mortality. This study aims to contribute to understanding the etiology of invasive and subcutaneous fungal infections, their associated risk factors, and to perceive the outcome of patients who developed invasive disease, raising awareness of these infections at a local level but also in a global context. A laboratory surveillance approach was conducted over a seven-year period and included: (i) cases of invasive and subcutaneous fungal infections caused by filamentous/dimorphic fungi, confirmed by either microscopy or positive culture from sterile samples, (ii) cases diagnosed as probable IFI according to the criteria established by EORTC/MSG when duly substantiated. Fourteen Portuguese laboratories were enrolled. Cases included in this study were classified according to the new consensus definitions of invasive fungal diseases (IFD) published in 2020 as follows: proven IFI (N = 31), subcutaneous fungal infection (N = 23). Those proven deep fungal infections (N = 54) totalized 71.1% of the total cases, whereas 28.9% were classified as probable IFI (N = 22). It was possible to identify the etiological fungal agent in 73 cases (96%). Aspergillus was the most frequent genera detected, but endemic dimorphic fungi represented 14.47% (N = 11) of the total cases. Despite the small number of cases, a high diversity of species were involved in deep fungal infections. This fact has implications for clinical and laboratory diagnosis, and on the therapeutic management of these infections, since different species, even within the same genus, can present diverse patterns of susceptibility to antifungals.

Histoplasmosis Diagnosed in Europe and Israel: A Case Report and Systematic Review of the Literature from 2005 to 2020

Human histoplasmosis is a mycosis caused by two distinct varieties of a dimorphic fungus: Histoplasma capsulatum var. capsulatum and H. capsulatum var. duboisii. In Europe, it is usually imported by migrants and travellers, although there have been some autochthonous cases, especially in Italy; however, most European physicians are unfamiliar with its clinical and pathological picture, particularly among immunocompromised patients without HIV infection. This systematic review of all the cases of histoplasmosis reported in Europe and Israel between 2005 and 2020 identified 728 cases diagnosed in 17 European countries and Israel described in 133 articles. The vast majority were imported (mainly from Central and South America), but there were also seven autochthonous cases (six in Europe and one in Israel). The patients were prevalently males (60.4%), and their ages ranged from 2 to 86 years. The time between leaving an endemic region and the diagnosis of histoplasmosis varied from a few weeks to more than 40 years. Progressive disseminated histoplasmosis was the most frequent clinical picture among people living with HIV infection (89.5%) or a different immunocompromising condition (57.1%), but it was also recorded in 6.2% of immunocompetent patients. Twenty-eight cases were caused by Histoplasma duboisii. Immunocompromised patients without HIV infection had the worst outcomes, with a mortality rate of 32%.

Endemic mycoses: epidemiology and diagnostic strategies

INTRODUCTION

The global frequency of endemic mycoses has considerably increased, mainly due to environmental changes, population growth in endemic areas, and the increase in HIV-related immunosuppressed status. Among the most frequent endemic mycoses are coccidioidomycosis in semi-desert climates, and paracoccidioidomycosis, and histoplasmosis in tropical climates. The inoculum can enter the host through the airway or directly through the skin. Lymphatic and hematogenous spread may involve the skin.

AREAS COVERED

In this article, we provide up-to-date epidemiological and diagnostic data on major (histoplasmosis, paracoccidioidomycosis, coccidioidomycosis, blastomycosis) and minor (talaromycosis, adiaspiromycosis, emergomycosis) endemic mycoses.

EXPERT OPINION

Endemic mycoses include diseases with a localized endemic area, and a few of them converge. These mycoses all have in common the airway involvement and can cause pulmonary symptoms following initial asymptomatic infection. Among the risk groups to acquire these mycoses are travelers from endemic areas, archeologists, speleologists, and immigrants. Promising and useful diagnostic tools have been developed in endemic mycoses; however, most of them are not standardized or available in low-income countries.

Acute histoplasmosis in travelers: a retrospective study in an Italian referral center for tropical diseases

Purpose: Histoplasmosis is a fungal infection acquired through inhalation of Histoplasma capsulatum microconidia, mostly present in the Americas. Both immunocompetent and immunocompromised patients can present a wide spectrum of signs/symptoms, ranging from mild disease to a severe, disseminated infection. The aim of this observational study is to describe histoplasmosis cases diagnosed in travelers and their clinical/radiological and therapeutic pattern.Methods: Retrospective study at the Department of Infectious - Tropical Diseases and Microbiology (DITM) of Negrar, Verona, Italy, between January 2005 and December 2015.Results: Twenty-three cases of acute histoplasmosis were diagnosed, 17 of which belong to the same cluster. Seven of the 23 patients (30.4%) were admitted to hospital, four of whom underwent invasive diagnostic procedures. Thirteen patients (56.5%) received oral itraconazole. All patients recovered, although nine (39.1%) had radiological persisting lung nodules at 12 month follow up.Conclusions: Clinical, laboratory and radiological features of histoplasmosis can mimic other conditions, resulting in unnecessary invasive diagnostic procedures. However, a history of travel to endemic areas and of exposure to risk factors (such as visits to caves and presence of bats) should trigger the clinical suspicion of histoplasmosis. Treatment may be indicated in severe or prolonged disease.

Histoplasmosis in an elderly polish tourist - a case report

BACKGROUND

Histoplasmosis is a mycosis caused by soil-based fungus Histoplasma capsulatum endemic in the USA, Latin America, Africa and South-East Asia. The disease is usually self-resolving, but exposure to a large inoculum or accompanying immune deficiencies may result in severe illness. Symptoms are unspecific with fever, cough and malaise as the most common. Thus, this is a case of disease which is difficult to diagnose and very rare in Europe. As a result, it is usually not suspected in elderly patients with cough and dyspnea.

CASE PRESENTATION

This is a case of a 78-year-old patient, admitted to our department due to respiratory failure, cough, shortness of breath, fever and weight loss with no response to antibiotics administered before the admission. Chest CT revealed numerous reticular and nodular infiltrations with distribution in all lobes. The cytopathology of BAL showed small parts of mycelium and numerous oval spores. Considering clinical presentation and history of travel to Mexico before onset of disease, pulmonary histoplasmosis was diagnosed. After introduction of antifungal treatment rapid improvement was achieved in terms of both clinical picture and respiratory function.

CONCLUSIONS

Since the risk of Histoplasma exposure in Europe is minimal, patients, who present with dyspnea, fever and malaise are not primarily considered for diagnosis of histoplasmosis. However, taking into account increasing popularity of travelling, also by elderly or patients with impaired immunity, histoplasmosis should be included into differential diagnosis.

Epidemiological aspects of travel-related systemic endemic mycoses: a GeoSentinel analysis, 1997-2017

Background

International travel has increased in the past few decades, placing more travellers at risk of acquiring systemic endemic mycoses. There are limited published data on systemic endemic mycoses among international travellers. We report epidemiological characteristics of non-migrant, international travellers who acquired systemic endemic mycoses during travel.

Methods

We analysed records of non-migrant international travellers with a confirmed diagnosis of histoplasmosis, coccidioidomycosis, paracoccidioidomycosis, blastomycosis or talaromycosis reported from 1997 through 2017 to GeoSentinel, a global surveillance network now consisting of 70 travel or tropical medicine centres in 31 countries.

Results

Sixty-nine records met the inclusion criteria. Histoplasmosis was most frequently reported; the 51 travellers with histoplasmosis had the lowest median age (30 years; range: 8-85) and shortest median duration of travel (12 days; range: 5-154). Coccidioidomycosis was reported in 14 travellers; travellers with coccidioidomycosis were older (median 62 years; range: 22-78) and had the longest median number of days between return from travel and presentation to a GeoSentinel site (55 days; range: 17-273). Almost all travellers with coccidioidomycosis were exposed in the USA. Other systemic endemic mycoses were less frequently reported, including blastomycosis (three travellers) and talaromycosis (one traveller).

Conclusions

Although relatively rare, systemic endemic mycoses should be considered as potential travel-related infections in non-migrant international travellers. Epidemiological exposures should be used to guide diagnostic evaluations and treatment.

Imported endemic mycoses in Spain: Evolution of hospitalized cases, clinical characteristics and correlation with migratory movements, 1997-2014

Endemic mycoses are systemic fungal infections. Histoplasmosis is endemic in all temperate areas of the world; coccidioidomycosis and paracoccidioidomycosis are only present in the American continent. These pathogens are not present in Spain, but in the last years there has been an increase of reported cases due to migration and temporary movements. We obtained from the Spanish hospitals records clinical and demographic data of all hospitalized cases between 1997 and 2014. There were 286 cases of histoplasmosis, 94 of Coccidioidomycosis and 25 of paracoccidioidomycosis. Overall, histoplasmosis was strongly related to HIV infection, as well as with greater morbidity and mortality. For the other mycoses, we did not find any immunosuppressive condition in most of the cases. Although we were not able to obtain data about clinical presentation of all the cases, the most frequently found was pulmonary involvement. We also found a temporal correlation between the Spanish population born in endemic countries and the number of hospitalized cases along this period. This study reflects the importance of imported diseases in non-endemic countries due to migratory movements.

Serious fungal infections in Portugal

There is a lack of knowledge on the epidemiology of fungal infections worldwide because there are no reporting obligations. The aim of this study was to estimate the burden of fungal disease in Portugal as part of a global fungal burden project. Most published epidemiology papers reporting fungal infection rates from Portugal were identified. Where no data existed, specific populations at risk and fungal infection frequencies in those populations were used in order to estimate national incidence or prevalence, depending on the condition. An estimated 1,510,391 persons develop a skin or nail fungal infection each year. The second most common fungal infection in Portugal is recurrent vulvovaginal candidiasis, with an estimated 150,700 women (15-50 years of age) suffering from it every year. In human immunodeficiency virus (HIV)-infected people, oral or oesophageal candidiasis rates were estimated to be 19.5 and 16.8/100,000, respectively. Candidaemia affects 2.19/100,000 patients, in a total of 231 cases nationally. Invasive aspergillosis is less common than in other countries as chronic obstructive pulmonary disease (COPD) is uncommon in Portugal, a total of 240 cases annually. The estimated prevalence of chronic pulmonary aspergillosis after tuberculosis (TB) is 194 cases, whereas its prevalence for all underlying pulmonary conditions was 776 patients. Asthma is common (10% in adults) and we estimate 16,614 and 12,600 people with severe asthma with fungal sensitisation and allergic bronchopulmonary aspergillosis, respectively. Sixty-five patients develop Pneumocystis pneumonia in acquired immune deficiency syndrome (AIDS) and 13 develop cryptococcosis. Overall, we estimate a total number of 1,695,514 fungal infections starting each year in Portugal.

Histoplasmosis in Israeli travelers

Histoplasmosis is a common endemic human mycoses acquired mostly in the Americas. We reviewed 23 cases of histoplasmosis in Israeli travelers; 22 had traveled to Central or South America and one to North America. Fourteen cases had been exposed to bat habitats and were symptomatic, presenting ≤ 3 months after their return. Asymptomatic patients (N = 9) were diagnosed during the evaluation of incidental radiological findings or because a travel partner had been suspected of Histoplasma infection, 16-120 months after their return. Serological testing was positive in 75% of symptomatic cases but only 22% of asymptomatic cases. Histoplasmosis should be considered in travelers returning from the Americas with respiratory or febrile illness within weeks of return, particularly if exposed to bat habitats. Travel history is essential in patients presenting with pulmonary nodules, even years after travel to endemic countries.

Geographic distribution of endemic fungal infections among older persons, United States

TOC summary: Incidence was highest for histoplasmosis and blastomycosis in the Midwest and for coccidioidomycosis in the West.

To investigate the epidemiology and geographic distribution of histoplasmosis, coccidioidomycosis, and blastomycosis in older persons in the United States, we evaluated a random 5% sample of national Medicare data from 1999 through 2008. We calculated national, regional, and state-based incidence rates and determined 90-day postdiagnosis mortality rates. We identified 776 cases (357 histoplasmosis, 345 coccidioidomycosis, 74 blastomycosis). Patient mean age was 75.7 years; 55% were male. Histoplasmosis and blastomycosis incidence was highest in the Midwest (6.1 and 1.0 cases/100,000 person-years, respectively); coccidioidomycosis incidence rate was highest in the West (15.2). On the basis of available data, for 86 (11.1%) cases, there was no patient exposure to a traditional disease-endemic area. Knowledge of areas where endemic mycosis incidence is increased may affect diagnostic or prevention measures for older adults at risk.

Management of fungal lung disease in the immunocompromised

Pulmonary mycoses are among the most feared infections encountered in immunocompromised patients. The problem is amplified by the increasing numbers of chronically immunocompromised patients that have substantially increased both the prevalence and clinical severity of infections caused by fungi. Moreover, fungal infections in this patient population pose challenges in diagnosis and management. Fortunately, recent advances in diagnostics and antifungal therapy, and their direct application to specific diseases, provide important new approaches to this complex and often seriously ill patient population. In this article we review the commonly occurring pulmonary fungal infections in the immunocompromised population with a particular focus on their management.

Histopathologic diagnosis of fungal infections in the 21st century

Fungal infections are becoming more frequent because of expansion of at-risk populations and the use of treatment modalities that permit longer survival of these patients. Because histopathologic examination of tissues detects fungal invasion of tissues and vessels as well as the host reaction to the fungus, it is and will remain an important tool to define the diagnostic significance of positive culture isolates or results from PCR testing. However, there are very few instances where the morphological characteristics of fungi are specific. Therefore, histopathologic diagnosis should be primarily descriptive of the fungus and should include the presence or absence of tissue invasion and the host reaction to the infection. The pathology report should also include a comment stating the most frequent fungi associated with that morphology as well as other possible fungi and parasites that should be considered in the differential diagnosis. Alternate techniques have been used to determine the specific agent present in the histopathologic specimen, including immunohistochemistry, in situ hybridization, and PCR. In addition, techniques such as laser microdissection will be useful to detect the now more frequently recognized dual fungal infections and the local environment in which this phenomenon occurs.

Epidemiology of endemic systemic fungal infections in Latin America

Although endemic mycoses are a frequent health problem in Latin American countries, clinical and epidemiological data remain scarce and fragmentary. These mycoses have a significant impact on public health, and early diagnosis and appropriate treatment remain important. The target population for endemic disease in Latin America is mostly represented by low-income rural workers with limited access to a public or private health system. Unfortunately, diagnostic tools are not widely available in medical centers in Latin America; consequently, by the time patients are diagnosed with fungal infection, many are already severely ill. Among immunocompromised patients, endemic mycoses usually behave as opportunistic infections causing disseminated rather than localized disease. This paper reviews the epidemiology of the most clinically significant endemic mycoses in Latin America: paracoccidioidomycosis, histoplasmosis, and coccidioidomycosis. The burdens of disease, typically affected populations, and clinical outcomes also are discussed.

[Imported histoplasmosis in Navarra: presentation of four cases]

OBJECTIVE

Histoplasmosis is a fungal infection caused by the dimorphic fungi Histoplasma capsulatum. Its incidence in Spain has increased in recent years, mainly due to the increased presence of immigrants from Latin America and increased travel to the continent for tourism and cooperation. Our aim was to review the clinical characteristics of cases of histoplasmosis diagnosed in our hospital during the last six years.

CASE REPORTS

We diagnosed 4 cases from 4 patients from South America, 3 of whom were HIV positive and 1 diagnosed with dermatomyositis was treated with immunosuppressive drugs. The laboratory diagnosis was carried out by histological and microbiological study, by culture and specific PCR directly on the sample.

DISCUSSION

As it is an imported infection there needs to be a high level of suspicion and a detailed history taken to get a diagnosis. This infection requires a differential diagnosis between febrile syndrome in immunosuppressed patients, both HIV positive and immunosuppressive therapy, which originate from endemic areas, or who have a history of staying in them.

Histoplasmosis and paracoccidioidomycosis in a non-endemic area: a review of cases and diagnosis

BACKGROUND

Histoplasmosis and paracoccidioidomycosis (PCM) have increased in Spain in recent years, due firstly to the migration from endemic regions and secondly to travelers returning from these regions. In non-endemic areas, diagnosis of both diseases is hampered by the lack of experience, long silent periods, and the resemblance to other diseases such as tuberculosis and sarcoidosis.

METHODS

A total of 39 cases of imported histoplasmosis and 6 cases of PCM diagnosed in the Spanish Mycology Reference Laboratory since 2006 were analyzed. Microbiological diagnosis was performed using classical methods and also a specific real-time polymerase chain reaction (RT-PCR) assay for each microorganism.

RESULTS

We had 9 cases of probable histoplasmosis in travelers and 30 cases in immigrants, 29 of whom were defined as proven. Paracoccidioidomycosis (PCM) cases were either immigrants or people who had lived for a long period of time in endemic regions, all of whom were classified as proven cases. Cultures showed a good sensitivity in detecting Histoplasma capsulatum in immigrants with proven histoplasmosis (73%); however, growth was very slow. The fungus was never recovered in traveler patients. Paracoccidioides brasiliensis was isolated in a culture only in one case of the proven PCM. Serological methods were not very reliable in immunocompromised patients with histoplasmosis (40%). A PCR-based technique for histoplasmosis detected 55.5% of the cases in travelers (probable cases) and 89% of the cases in immigrants (proven). The PCR method for PCM detected 100% of the cases.

CONCLUSIONS

These kinds of mycoses are increasingly frequent in non-endemic areas, and newer and faster techniques should be used to reach an early diagnosis. The RT-PCR techniques developed appear to be sensitive, specific, and fast and could be helpful to detect those mycoses. However, it is also essential that physicians perform differential diagnosis in individuals coming from endemic areas.

Imported histoplasmosis: two distinct profiles in travelers and immigrants

BACKGROUND

Histoplasmosis is acquiring importance in nonendemic areas due to the increase in travel and immigration, being the most common systemic mycosis acquired by European travelers. Epidemiological studies show that the incidence of Histoplasma infection in these patients may be higher than previously believed and a wide clinical spectrum of disease may be observed.

METHODS

Cases of histoplasmosis diagnosed at a Tropical Medicine Referral Unit in Madrid, Spain, during the period January 1996 to December 2006 were reviewed.

RESULTS

Ten cases of histoplasmosis in travelers and immigrants are described. Five HIV-positive patients (four immigrants and one expatriate) all presented with progressive disseminated disease. Five HIV-negative patients (travelers) all presented with pulmonary disease: four with an acute pulmonary form (one with pleural involvement) and one patient was found to have residual pulmonary disease (lung nodule). Three of the travelers also had rheumatologic manifestations (arthromyalgias or arthritis).

CONCLUSIONS

Clinicians in nonendemic areas may be faced with patients with a diagnosis of histoplasmosis and although Histoplasma infection can have a varied and nonspecific clinical presentation, imported histoplasmosis may have two distinct profiles. Previously, healthy travelers may be exposed in endemic areas and mainly develop acute forms of the disease with a favorable outcome. Immigrants or expatriates from endemic areas who may be immunosuppressed due to HIV infection may experience reactivation of latent disease developing disseminated forms with high mortality rates. This infection should be considered in the differential diagnosis of diseases affecting travelers and immigrants.

[Imported infectious diseases in Spain]

In Spain, owing to the rise of international travels and immigration, the number of patients with imported infectious diseases has increased, many of them from tropical or subtropical areas. In parallel, there has been a multiplication in the number of scientific papers with Spanish authors about imported infections due to parasites, fungus, mycobacteriae, bacteriae or viruses. The risk for public health is low, althought for their correct prevention and control it is important to ease an universal access to healthcare and fair socioeconomic conditions, along with maintaining an updated clinical and epidemiological training of the health personnel. These nationwide measures must be supplemented with worldwide initiatives of global control of these infections.

Cavitary pulmonary disease

A pulmonary cavity is a gas-filled area of the lung in the center of a nodule or area of consolidation and may be clinically observed by use of plain chest radiography or computed tomography. Cavities are present in a wide variety of infectious and noninfectious processes. This review discusses the differential diagnosis of pathological processes associated with lung cavities, focusing on infections associated with lung cavities. The goal is to provide the clinician and clinical microbiologist with an overview of the diseases most commonly associated with lung cavities, with attention to the epidemiology and clinical characteristics of the host.

Bat-associated histoplasmosis can be transmitted at entrances of bat caves and not only inside the caves

Our observation of histoplasmosis cases augments the current knowledge on transmission by bats. In the presented cases, the only contact happened in the proximity of a bat cave but not inside the cave. We wish to communicate and stress that even outside of caves, bats may disperse the organism.

Pulmonary Histoplasmosis in Three Austrian Travelers After a Journey to Mexico

Three Austrian travelers (a 37-year-old woman, a 47-year-old woman and a 47-year-old man) presented with fever, dyspnea, thoracodynia, cephalea, arthralgia and fatigue 4 weeks after visiting a bat cave in Mexico. Computed tomography of the lungs showed bilateral nodular infiltrates in all three patients and enlarged mediastinal lymph nodes in two patients. In all patients, specific IgM antibodies against Histoplasma capsulatum could be detected. After treatment with itraconazole 200 mg q.d. orally for 2 months, the patients had no further complaints and the pulmonary infiltrates had resolved.

Oral histoplasmosis after radiation therapy for laryngeal squamous cell carcinoma

Histoplasmosis is a usually asymptomatic deep fungal infection of tropical origin with respiratory entry and possible oral, pharyngeal, or metastatic localization. The condition represents an important imported systemic mycosis with oral involvement. We report the case of a patient who developed an oropharyngeal reactivation of a latent Histoplasma infection after receiving local antitumoral radiation therapy of the neck. H capsulatum was shown to be present in the lesion by both histopathology and staining, and was deduced to be the causative organism of the disease.

[Assessment of a quantitative PCR method for clinical diagnosis of imported histoplasmosis]

OBJECTIVE

Evaluation of the usefulness of a quantitative real-time polymerase chain reaction-based (RT-PCR) technique for clinical diagnosis of histoplasmosis.

METHODS

Primers and probes were designed on the basis of sequences from the ITS regions of ribosomal DNA of 20 clinical strains of Histoplasma capsulatum. LightCycler procedures (Roche Applied Science) were used with probes marked by fluorescence resonance energy transfer (FRET). Reproducibility, sensitivity, and specificity were analyzed. In addition, an internal control was designed to identify false negative results by PCR inhibition. The RT-PCR assay was tested in 22 clinical samples from 14 patients with proven histoplasmosis. In addition, 30 samples from patients with febrile neutropenia or mycoses other than histoplasmosis, and from healthy volunteers were analyzed as controls.

RESULTS

The limit of detection of the assay was 1 fg of genomic DNA per microl of sample. The PCR-based technique was reproducible and highly specific. Positive results were obtained in 11/14 (78.6%) patients and in 17/22 (77.3%) clinical samples. RT-PCR was positive in 100% of respiratory secretions and bone marrow samples, but only 70% of sera (p < 0.01). Mean fungal DNA value was 23.1 fg/microl in serum and 4.85 x 10(3) fg/microl in respiratory and bone marrow samples. RT-PCR results were positive in serum from three HIV patients for which antibody detection by immunodiffusion was negative. Specificity was 100%, since PCR results were negative for all the control samples.

CONCLUSION

Thes RT-PCR technique is a sensitive, specific method for early diagnosis of histoplasmosis, particularly when respiratory secretions or bone marrow samples are analyzed. The reliability is lower in serum, but it can be used as an additional, complementary technique to culture and serology in HIV patients.