The size of the problem
Estimates of fungal infection burden are derived from multiple sources and are all crude estimates. Better local estimates are required. Some infections are common everywhere (Candida vaginitis as an example), others much more common in tropical underdeveloped countries (cryptococcal meningitis in AIDS), others in temperate, industrialised nations (ie SAFS). (view: How Common are Fungal Diseases)
The economic burden of invasive fungal infections is high because these patients spend longer in hospital and many antifungal drugs are expensive. An overview from the USA in 2002 (prior to licensure of echinocandins or voriconazole and posaconazole) indicates a country cost of at least $2.6 billion (see here). Late diagnosis contributes substantially to the cost.
Created by Patrick Hickey for the “Killer Fungus” exhibit at the 2016 Royal Society Summer Science Exhibition http://www.killerfungus.org
Impact of fungal infections
- Cryptococcal meningitis – 10% death rate in the USA, >70% in Africa. 180,000 deaths annually. Diagnosis simple with antigen test, but often late and appropriate medication not available.
- Disseminated histoplasmosis in AIDS – >80% mortality rate in USA, ~50% in Central America, 100% if untreated.
- Invasive aspergillosis – 50% mortality if treated, 100% if not. Diagnosis difficult; treatment often too late, and only partially effective.
- Chronic pulmonary aspergillosis – diagnosis often confused with TB; requires radiology and Aspergillus antibody test; 30% mortality rate in 6 months, often by coughing up blood (haemoptysis). Treatment partially successful but long term.
- Pneumocystis pneumonia - ~15% mortality in AIDS in UK, 30% in AIDS in Africa, ~50% non-AIDS, 100% if not diagnosed and treated. Diagnosis difficult without PCR or fluorescence microscopy. Treatment straightforward and available.
- Candida bloodstream infection - ~40% mortality, treated. Diagnosis by blood culture. Treatment straightforward, best drugs expensive. 120,000 deaths per year.
- SAFS – increased risk of asthmatic death (estimated to be 450,000 annually worldwide.)
- Oral and oesophageal thrush – unpleasant, reduced food intake and weight loss.
- ABPA and SAFS – breathlessness with severe asthma, reducing work capability especially for manual workers, co-morbidity issues with smoke from home cooking – easy diagnosis (skin prick tests), if considered, antifungal treatment 60-80% effective.
- Chronic pulmonary aspergillosis – progressive breathlessness and weight loss, with significant hospitalisation and medication costs (typically mis-directed).
- Fungal eye infection – usually results in unilateral blindness as diagnosis late, good outcome if treated early. Diagnosis requires expert input; treatment intensive initially but unaffordable for most afflicted.
- Candida vaginitis – mis-diagnosis and anxiety major problems; impaired sex life and therefore relationship issues.
- Fungal hair infection – most common in black children, who suffer patches of hair loss and psychological problems as a result. Diagnosis and treatment usually straightforward and highly effective.
Diagnosis of fungal disease- some global issues ( Denning, Edinburgh 2015)
Barnes R & Rautemaa-Richardson R (2014) Fungi — forgotten foes. The Bulletin, Royal College of Pathologists, 167, pp. 161-162. PDF