Histoplasmosis in Africa: An emerging or a neglected disease?

Estimated Burden of Serious Fungal Infections in Ghana

Fungal infections are increasingly becoming common and yet often neglected in developing countries. Information on the burden of these infections is important for improved patient outcomes. The burden of serious fungal infections in Ghana is unknown. We aimed to estimate this burden. Using local, regional, or global data and estimates of population and at-risk groups, deterministic modelling was employed to estimate national incidence or prevalence. Our study revealed that about 4% of Ghanaians suffer from serious fungal infections yearly, with over 35,000 affected by life-threatening invasive fungal infections. Incidence of cryptococcal meningitis, Pneumocystis jirovecii pneumonia, and disseminated histoplasmosis cases in AIDS was estimated at 6275, 12,610 and 724, respectively. Oral and esophageal candidiasis collectively affect 27,100 Ghanaians and 42,653 adult asthmatics are estimated to have fungal asthma. We estimate a prevalence of 12,620 cases of chronic pulmonary aspergillosis (CPA and an incidence of 1254 cases of invasive aspergillosis (IA). Estimated cases of candidemia and candida peritonitis cases were 1446 and 217, respectively. The estimated prevalence of recurrent vulvovaginal candidiasis (RVVC) and tinea capitis was 442,621 and 598,840, respectively. Mucormycosis and fungal keratitis each may affect 58 and 810 Ghanaians. These data highlight the urgent need for intensified awareness to improve diagnosis and management.

Histoplasma duboisii of the femoral bone

Histoplasmosis due to Histoplasma duboisii is an emerging AIDS-defining opportunistic infection in HIV positive seen predominantly on the African continent between the Tropics of Cancer and Capricorn. Histoplasma duboisii is an invasive fungal organism with tropism for lymph nodes, skin and bones. The infection occurs more in patients with a CD4 count <50/mm³ and is usually dissemnnated Histoplasmosis due to Histoplasma duboisii is an emerging AIDS-defining opportunistic infection in HIV positive seen predominantly on the African continent between the Tropics of Cancer and Capricorn. Histoplasma duboisii is an invasive fungal organism with tropism for lymph nodes, skin and bones. The infection occurs more in patients with a CD4 count <50/mm³ and is usually disseminated. Literature reports of its occurrence in HIV negative patients are scanty. We report a case of histoplasma dubiosii infection of the left femur in a 9 year old HIV negative Nigerian with swelling in the left thigh of 5 months duration. Oral antibiotics and analgesics were prescribed for the patient with satisfactory clinical outcome. To our knowledge, this is the first reported case in an immunocompetent child in Nigeria. Literature reports of its occurrence in HIV negative patients are scanty. We report a case of histoplasma dubiosii infection of the left femur in a 9 year old HIV negative Nigerian with swelling in the left thigh of 5 months duration. Oral antibiotics and analgesics were prescribed for the patient with satisfactory clinical outcome. To our knowledge, this is the first reported case in an immunocompetent child in Nigeria.

An immigrant with acquired immunodeficiency syndrome presenting with a rash: A case report

A 58-year-old woman from Zimbabwe, with a history of untreated human immunodeficiency virus, presented with leonine facies and a diffuse rash. The rash occurred in the context of a 1-year history of constitutional symptoms and cognitive decline. Laboratory investigations confirmed that her human immunodeficiency virus had progressed to acquired immunodeficiency syndrome. Through imaging, tissue biopsies, and polymerase chain reaction, a diagnosis of disseminated histoplasmosis was made. Since there was no history of travel and histoplasmosis is not locally endemic, the patient likely contracted this fungal infection more than 7 years ago, while living in Africa. We speculate that the histoplasmosis remained latent until her immune system began to decline. The work-up and management of this rare cutaneous presentation of a systemic disease, which should be added to the list of “great mimickers” in dermatology, are discussed.

Infection in Immunocompromised Hosts: Imaging

Immunocompromised patients are encountered with increasing frequency in clinical practice. In addition to the acquired immunodeficiency syndrome (AIDS), therapy for malignant disease, and immune suppression for solid organ transplants, patients are now rendered immunosuppressed by advances in treatment for a wide variety of autoimmune diseases. The number of possible infecting organisms can be bewildering. Recognition of the type of immune defect and the duration and depth of immunosuppression (particularly in hematopoietic and solid organ transplants) can help generate a differential diagnosis. Radiologic imaging plays an important role in the detection and diagnosis of chest complications occurring in immunocompromised patients; however, chest radiography alone seldom provides adequate sensitivity and specificity. High-resolution computed tomography (CT) can provide better sensitivity and specificity, but even CT findings may be nonspecific findings unless considered in conjunction with the clinical context. Combination of CT pattern, clinical setting, and immunologic status provides the best chance for an accurate diagnosis. In this article, CT findings have been divided into 4 patterns: focal consolidation, nodules/masses, small/micronodules, and diffuse ground-glass attenuation/consolidation. Differential diagnoses are suggested for each pattern, adjusted for both AIDS and non-AIDS immunosuppressed patients.

Pulmonary histoplasmoma: a disguised malady

Histoplasmosis is a mycosis caused by the dimorphic fungus, Histoplasma capsulatum, which is transmitted via dust and aerosols. Lung involvement is the most common, with a varied clinical presentation. Although it is not the only source of infection, H. capsulatum is frequently found in bat guano, which is the reason why it is highly prevalent among caving practitioners. The solitary histoplasmoma of the lung is an unusual and chronic manifestation of this entity, which mimics, or at least is frequently misconstrued, as a malignancy. Almost invariably, the diagnosis of this type of histoplasmosis presentation is achieved after lung biopsy. The authors present the case of a young woman who sought medical care because of chest pain. The diagnostic work-up revealed the presence of a pulmonary nodule. She was submitted to a thoracotomy and wedge pulmonary resection. The histologic analysis rendered the diagnosis of histoplasmoma. This report aims to call attention to this diagnosis as the differential diagnosis of a pulmonary nodule.

Histoplasma capsulatum antigen detection tests as an essential diagnostic tool for patients with advanced HIV disease in low and middle income countries: A systematic review of diagnostic accuracy studies

INTRODUCTION

Disseminated histoplasmosis, a disease that often resembles and is mistaken for tuberculosis, is a major cause of death in patients with advanced HIV disease. Histoplasma antigen detection tests are an important addition to the diagnostic arsenal for patients with advanced HIV disease and should be considered for inclusion on the World Health Organization Essential Diagnostics List.

OBJECTIVE

Our objective was to systematically review the literature to evaluate the diagnostic accuracy of Histoplasma antigen tests in the context of advanced HIV disease, with a focus on low- and middle-income countries.

METHODS

A systematic review of the published literature extracted data on comparator groups, type of histoplasmosis, HIV status, performance results, patient numbers, whether patients were consecutively enrolled or if the study used biobank samples. PubMed, Scopus, Lilacs and Scielo databases were searched for published articles between 1981 and 2018. There was no language restriction.

RESULTS

Of 1327 screened abstracts we included a total of 16 studies in humans for further analysis. Most studies included used a heterogeneousgroup of patients, often without HIV or mixing HIV and non HIV patients, with disseminated or non-disseminated forms of histoplasmosis. Six studies did not systematically use mycologically confirmed cases as a gold standard but compared antigen detection tests against another antigen detection test. Patient numbers were generally small (19-65) in individual studies and, in most (7/10), no confidence intervals were given. The post test probability of a positive or negative test were good suggesting that this non invasive diagnostic tool would be very useful for HIV care givers at the level of reference hospitals or hospitals with the infrastructure to perform ELISA tests. The first results evaluating point of care antigen detection tests using a lateral flow assay were promising with high sensitivity and specificity.

CONCLUSIONS

Antigen detection tests are promising tools to improve detection of and ultimately reduce the burden of histoplasmosis mortality in patients with advanced HIV disease.

Estimated Burden of Serious Fungal Infections in Malawi

Despite efforts to address the burden of fungal infections in Malawi, the prevalence and incidence remain largely unknown. We assessed the annual burden in the general population and among populations at high risk and fungal infection frequencies in each particular population to estimate the national incidence or prevalence. The Malawi population is approximately 17.7 million (2017), with 48% under 15 years of age. Approximately 8% of the population is HIV positive. The most common infections are present in HIV/AIDS patients, with oral candidiasis being the commonest. Life threatening infections among those with AIDS patients include cryptococcal meningitis (8200 cases) and Pneumocystis pneumonia (3690 cases). Pulmonary TB is common, but extra pulmonary TB is rare; an estimated 2329 people have chronic pulmonary aspergillosis after TB. Asthma is a significant problem in Malawi, with an estimated 680,000 adults affected (4.67%) and 14,010 cases of allergic bronchopulmonary aspergillosis (ABPA). Tinea capitis is estimated to be present in over 670,000 young people (21% of school age children). The annual incidence of fungal keratitis is difficult to estimate, but as cases are frequently seen in the eye department, is likely to be a minimum of 1825 (10.3/100,000) cases. Among the most serious infections, cryptococcal meningitis and Pneumocystis pneumonia are top of the list. Overall, some 1,338,523 (7.54%) people are affected by a serious fungal infection in Malawi. These basic estimates are limited, due to poor record keeping, and require epidemiological studies to validate or modify the substantial burden estimates. National surveillance of fungal infections is urgently needed.

Prior subclinical histoplasmosis revealed in Nigeria using histoplasmin skin testing

Objectives

Disseminated histoplasmosis is an AIDS-defining illness. Histoplasmosis is commonly misdiagnosed as tuberculosis. Nigeria has the second highest number of people living with HIV/AIDS in Africa. The present study was carried out to investigate the prevalence of skin sensitivity amongst Nigerians to histoplasmin.

Design

A cross-sectional study was conducted in six centres across five geopolitical zones of Nigeria.

Methods

We recruited both healthy non-HIV and HIV-positive adults with CD4 count ≥ 350 cells/mm³ regardless of their ART status from March to May 2017. Skin tests were performed intradermally; induration ≥5 mm were considered to be histoplasmin positive.

Results

750 participants were recruited from Lagos (n = 52), Yola (n = 156), Ilorin (n = 125), Calabar (n = 120), Ibadan (n = 202) and Benin (n = 95). 467 (62.3%) were HIV negative, 247 (32.9%) were HIV positive and 36 (4.8%) did not know their HIV status. A total of 32/735 (4.4%) participants had a positive skin test. Study centre (p<0.001), education (p = 0.002) and age (p = 0.005) appeared to be significantly associated with positive skin reactivity at the 0.5% significance level, while sex (p = 0.031) and occupation (p = 0.031) would have been significant at the 5% significance level. Males had a higher rate of reactivity than females (p = 0.031, 7% vs 3%). The highest positive rates were recorded from Benin City (13/86 (15%)) and Calabar (7/120 (6%)) and no positives were recorded in Lagos (p<0.001). HIV status was not statistically significant (p = 0.70).

Conclusion

Histoplasmosis diagnostics should be included in the Nigerian HIV guidelines. Epidemiological vigilance of progressive disseminated histoplasmosis should be considered by local health authorities.

The Burden of Serious Fungal Infections in Cameroon

Fungal infections are frequent in Cameroon, and invasive fungal infections are sometimes detected, usually in HIV-infected patients. For these reasons, we have estimated the burden of fungal infections. Using published literature and population estimates for the at-risk group, we used deterministic modelling to derive national incidence and prevalence estimates for the most serious fungal diseases. HIV infection is common and an estimated 120,000 have CD4 counts <200 × 10⁶/mL and commonly present with opportunistic infection. Oesophageal candidiasis in HIV is common, and in poorly controlled diabetics. We estimate 6720 cases of cryptococcal meningitis, 9000 of Pneumocystis pneumonia, 1800 of disseminated histoplasmosis annually complicating AIDS, and 1200 deaths from invasive aspergillosis in AIDS, but there are no data. We found that 2.4% of adults have chronic obstructive pulmonary disease (COPD) and 2.65% have asthma, with "fungal asthma" affecting 20,000. Chronic pulmonary aspergillosis probably affects about 5000 people, predominantly after tuberculosis but also with COPD and other lung diseases. Also, tinea capitis in schoolchildren is frequent. Overall, an estimated 1,235,775 people are affected by a serious fungal infection. There is an urgent need for government and clinician attention, improved laboratory facilities, fungal diagnostic tests, and competent laboratory technicians, as well as all World Health Organization (WHO)-endorsed essential antifungal drugs to be made available, as only fluconazole is registered and available in the country.