Fusariosis

What is Fusariosis?

Fusarium infections are caused by Fusarium spp., which are a group of pathogenic moulds.^1,2 They are saprotrophic organisms found largely in soil, decomposing organic matter or plants.¹

Infections by Fusarium spp. in otherwise healthy individuals are often superficial, limited to single organs and respond well to therapy.³ In contrast, immunocompromised patients are more susceptible to invasive fusariosis (IF) and experience more severe symptoms, with manifestations such as invasive sinusitis, pneumonia or skin lesions.³

Pathogenesis

The main routes of infection by Fusarium are inhalation of airborne microconidia or direct inoculation through traumatic injury, including burns.² These moulds can cause superficial infections, such as keratitis, in immunocompetent hosts, and severe disseminated infections in immunocompromised individuals, which frequently presents as fungaemia.² Endogenous endophthalmitis is a rare complication of IF and can occasionally cause visual loss or blindness.¹

Epidemiology

The global incidence of IF has not been formally assessed; however, reporting trends show an increase in cases over the last 10 years.¹ The incidence and prevalence of Fusarium spp. infections vary depending on the underlying disease and geographical region, reaching 20 per 1000 recipients of allogeneic haematopoietic stem cell transplantation (HSCT) with human leukocyte antigen-mismatched related donors in Brazil and the USA.²

The 30-day mortality rate for IF ranges from 43 to 67% and is particularly high for infections involving F. solani and F. proliferatum.¹

Risk factors

Known risk factors for IF include:¹

• Acute myeloid leukaemia (AML)
• Allogenic HSCT
• Cytomegalovirus (CMV) reactivation
• Presence of skin lesions positive for Fusarium spp. at baseline

Pathogenic species

Several Fusarium species can cause disease in humans.³ The F. solani complex and F. oxysporum complex are most commonly associated with IF.²