Incidence of Histoplasmosis in a Cohort of People with HIV: From Estimations to Reality

Global incidence and mortality of severe fungal disease

Current estimates of fungal disease incidence and mortality are imprecise. Population at risk denominators were used to estimate annual incidence for 2019-21. Extensive literature searches from 2010 to 2023 were combined with over 85 papers on individual country and global disease burden. Crude and attributable mortality were estimated using a combination of untreated mortality, the proportion of patients who are treated, and percentage survival in treated patients. Awareness, guidelines, and accessibility of diagnostics and therapies informed the ratio of treated to untreated cases. Estimates do not include influenza or COVID-19 outbreaks. Data from more than 120 countries were included. Annually, over 2 113 000 people develop invasive aspergillosis in the context of chronic obstructive pulmonary disease, intensive care, lung cancer, or haematological malignancy, with a crude annual mortality of 1 801 000 (85·2%). The annual incidence of chronic pulmonary aspergillosis is 1 837 272, with 340 000 (18·5%) deaths. About 1 565 000 people have a Candida bloodstream infection or invasive candidiasis each year, with 995 000 deaths (63·6%). Pneumocystis pneumonia affects 505 000 people, with 214 000 deaths (42·4%). Cryptococcal meningitis affects 194 000 people, with 147 000 deaths (75·8%). Other major life-threatening fungal infections affect about 300 000 people, causing 161 000 deaths (53·7%). Fungal asthma affects approximately 11·5 million people and might contribute to 46 000 asthma deaths annually. These updated estimates suggest an annual incidence of 6·5 million invasive fungal infections and 3·8 million deaths, of which about 2·5 million (68%; range 35-90) were directly attributable.

Histoplasmosis: A systematic review to inform the World Health Organization of a fungal priority pathogens list

Histoplasmosis, a significant mycosis primarily prevalent in Africa, North and South America, with emerging reports globally, poses notable health challenges, particularly in immunocompromised individuals such as people living with HIV/AIDS and organ transplant recipients. This systematic review, aimed at informing the World Health Organization's Fungal Priority Pathogens List, critically examines literature from 2011 to 2021 using PubMed and Web of Science, focusing on the incidence, mortality, morbidity, antifungal resistance, preventability, and distribution of Histoplasma. We also found a high prevalence (22%-44%) in people living with HIV, with mortality rates ranging from 21% to 53%. Despite limited data, the prevalence of histoplasmosis seems stable, with lower estimates in Europe. Complications such as central nervous system disease, pulmonary issues, and lymphoedema due to granuloma or sclerosis are noted, though their burden remains uncertain. Antifungal susceptibility varies, particularly against fluconazole (MIC: ≥32 mg/l) and caspofungin (MICs: 4-32 mg/l), while resistance to amphotericin B (MIC: 0.125-0.16 mg/l), itraconazole (MICs: 0.004-0.125 mg/l), and voriconazole (MICs: 0.004-0.125 mg/l) remains low. This review identifies critical knowledge gaps, underlining the need for robust, globally representative surveillance systems to better understand and combat this fungal threat.

Incidence of histoplasmosis in patients receiving TNF-alpha inhibitors: A systematic review and meta-analysis

BACKGROUND

Immunobiological drugs such as TNF-α inhibitors are valuable in rescue therapy for autoimmune diseases such as rheumatoid arthritis and inflammatory bowel disease (IBD), but they increase the risk of infectious complications. Histoplasmosis is a significant concern in patients living in endemic regions, however, few studies have assessed the incidence of Histoplasma infection during therapy, and classic estimates may underestimate the risk. This study aimed to produce an updated risk estimate of histoplasmosis in patients on TNF-α blocking therapy.

METHODS

This is a systematic review and meta-analysis of studies that contain parameters for calculating the risk of histoplasmosis in people who use TNF-α inhibitors, to produce a risk estimate.

RESULTS

We identified 11 studies with the necessary parameters for inclusion in the meta-analysis, most of which were from North America. The incidence rate of histoplasmosis found was 33.52 cases per 100,000 patients treated with TNF-ɑ inhibitors (95% CI 12.28-91.46). Considering only studies evaluating monoclonal antibodies, the calculated incidence was 54.88/100,000 patients treated (95%CI 23.45-128.34). In subgroup analysis, the incidence was much higher in patients with IBD compared to rheumatic diseases. There was significant heterogeneity among the studies.

CONCLUSION

The risk of histoplasmosis during TNF-α inhibitory therapy may be considerably higher than that found in classical estimates, especially in patients with IBD. There is a lack of studies evaluating histoplasmosis in large endemic areas, such as Central and South America.

Evaluation of the Histoplasma capsulatum 100-kilodalton antigen dot blot for the rapid diagnosis of progressive histoplasmosis in HIV/AIDS patients

Among people living with HIV (PLHIV), progressive disseminated histoplasmosis (PDH) represents an important cause of mortality. Since antigen detection allows a rapid diagnosis and the instauration of a specific treatment this study aimed to evaluate the analytical performance of the Hcp100 dot blot, an in-house assay that detects the Histoplasma capsulatum 100-kilodalton antigen in urine and compare it with 2 commercially available assays the Histoplasma Urine Antigen Lateral Flow Assay (MVD-LFA) (MiraVista® Diagnostics) and the Clarus Histoplasma Galactomannan EIA (Clarus HGM) (IMMY). Urine specimens from 23 PLHIV with PDH, 13 patients with other infectious diseases, and 20 healthy individuals were tested. The Hcp100 dot blot showed higher sensitivity (87.0%), specificity (97.0%) and accuracy (92.9%) than the MVD-LFA (73.9%, 78.8%, and 76.8%, respectively) and the Clarus HGM (78.3%, 90.9%, and 85.7%, respectively). The Hcp100 dot blot had high analytical performance and would be a valuable screening tool for diagnosing PDH among PLHIV.

The incidence of histoplasmosis and cryptococcal antigenemia among patients attending a large HIV clinic in Trinidad

Our aim was to determine the incidence disseminated histoplasmosis and cryptococcal antigenemia among 280 patients with a CD4<350 cells/mm³ attending a large HIV clinic in Trinidad over the period November 2021-June 2022. Sera were screened for cryptococcal antigen (CrAg) using the Immy CrAg Immunoassay (EIA) and the Immy CrAg lateral flow assay (LFA). Urine was screened for Histoplasma antigen using the Immy EIA and the Optimum Imaging Diagnostics (OIDx) LFA. For the purposes of analysis, it was assumed, that all patients with positive urine Histoplasma antigen tests by both EIA and LFA and those with a single positive urine Histoplasma antigen test and clinical features of disseminated histoplasmosis were true positives. The incidence of probable disseminated histoplasmosis and cryptococcal antigenemia were 6.4% (18/280) and 2.5% (7/280) respectively. The sensitivity and specificity of the Immy Histoplasma EIA were 100% (95% CI, 81.5%-100%) and 98.5% (95% CI, 96.1% - 99.6%) respectively as compared to the OIDx Histoplasma LFA of 88.9% (95% CI, 65.3% - 98.6%) and 93.9% (95% CI, 90.3% - 96.5%) respectively, with substantial agreement between the 2 test kits (Kappa value = 0.763; 95% CI 0.685, 0.841). Testing for disseminated histoplasmosis in HIV patients is important in endemic areas.

Current situation of endemic mycosis in the Americas and the Caribbean: Proceedings of the first international meeting on endemic mycoses of the Americas (IMEMA)

BACKGROUND

The Americas are home to biologically and clinically diverse endemic fungi, including Blastomyces, Coccidioides, Emergomyces, Histoplasma, Paracoccidioides and Sporothrix. In endemic areas with high risk of infection, these fungal pathogens represent an important public health problem.

OBJECTIVES

This report aims to summarise the main findings of the regional analysis carried out on the status of the endemic mycoses of the Americas, done at the first International Meeting on Endemic Mycoses of the Americas (IMEMA).

METHODS

A regional analysis for the Americas was done, the 27 territories were grouped into nine regions. A SWOT analysis was done.

RESULTS

All territories reported availability of microscopy. Seventy percent of territories reported antibody testing, 67% of territories reported availability of Histoplasma antigen testing. None of the territories reported the use of (1-3)-β-d-glucan. Fifty two percent of territories reported the availability of PCR testing in reference centres (mostly for histoplasmosis). Most of the territories reported access to medications such as trimethoprim-sulfamethoxazole, itraconazole, voriconazole and amphotericin B (AMB) deoxycholate. Many countries had limited access to liposomal formulation of AMB and newer azoles, such as posaconazole and isavuconazole. Surveillance of these fungal diseases was minimal.

CONCLUSIONS

A consensus emerged among meeting participants, this group concluded that endemic mycoses are neglected diseases, and due to their severity and lack of resources, the improvement of diagnosis, treatment and surveillance is needed.

Prevalence of Histoplasmosis among Persons with Advanced HIV Disease, Nigeria

We sought to determine the prevalence of probable disseminated histoplasmosis among advanced HIV disease (AHD) patients in Nigeria. We conducted a cross-sectional study in 10 sites across 5 of 6 geopolitical zones in Nigeria. We identified patients with urinary samples containing CD4 cell counts <200 cells/mm³ or World Health Organization stage 3 or 4 disease who also had >2 clinical features of disseminated histoplasmosis, and we tested them for Histoplasma antigen using a Histoplasma enzyme immune assay. Of 988 participants we recruited, 76 (7.7%) were antigen-positive. The 76 Histoplasma antigen-positive participants had significantly lower (p = 0.03) CD4 counts; 9 (11.8%) were also co-infected with tuberculosis. Most antigen-positive participants (50/76; 65.8%; p = 0.015) had previously received antiretroviral treatment; 26/76 (34.2%) had not. Because histoplasmosis is often a hidden disease among AHD patients in Nigeria, Histoplasma antigen testing should be required in the AHD package of care.