Fusariosis is an infection caused by species of Fusarium mold. Infections of these mold species are most commonly seen in people who are immunocompromised, meaning their immune system has been weakened in some way. Fusariosis is treatable, but requires that the infection be diagnosed quickly. In addition, successful treatment requires that the patient's immune system be bolstered in some way to prevent reinfection.
While in the past other species of mold have been responsible for opportunistic infections in immunocompromised people, species of Fusarium mold are increasingly more common. The main reason for this shift is that new and more effective types of chemotherapy treatments have lead to a greater degree of immune system suppression in many patients, leaving these people more vulnerable to infection. People with a hematologic malignancy, such as leukemia, and people who have undergone bone marrow transplants are particularly at risk because these two groups of patients tend to undergo highly immunosuppressive chemotherapy. Fusariosis can be lethal in these cases.
Infections with Fusarium mold species are more common during warm, rainy seasons. This is because the mold releases more spores in such climates. The most common methods of infection are by breathing in the spores, or via infection through breaks in the skin.
People with fusariosis typically have symptoms such as a high fever that does not respond to treatment with antimicrobial drugs, pulmonary infection, and skin lesions. The lesions are tender to the touch, and are usually located in the extremities of the body. One or more organs may also be affected. An accurate diagnosis often requires a tissue biopsy to differentiate between Fusarium and other species of mold.
Fusariosis is particularly dangerous because the species of Fusarium molds that infect humans are capable of producing fungal toxins known as mycotoxins. The toxins produced by these species are able to further suppress the immune system, thus helping the infection to spread. With the immune system further suppressed, the infection is even more difficult to treat effectively.
Another factor that increases the difficulty of treatment is that these infections are often resistant to antifungal medications. Currently, the main drugs used to treat such infections are amphotericin-B and a broad-spectrum antifungal called voriconazole. Due to the issues of drug resistance and toxin production by the mold, this treatment is typically combined with additional medication to help stimulate the growth and activation of new immune cells. In some cases, infected tissue must be surgically removed to prevent reinfection.