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Lichtheimia corymbifera is a saprotrophic fungi under the phyla zygomycota. L.corymbifera is known to cause pulmonary, CNS, rhinocerebral, or cutaneous types of infection in animals and humans with impaired immunity.

Identification
L.corymbifera is microscopic and ubiquitous in nature usually inhabiting soil or dead plant material. It is a thermotolerant species that produces small, black spores contained inside a pear-shaped (pyriform) sporangia. The species is characterized by a conically shaped columella and a short, pronounced projection, a funnel-shaped apophysis, on the top. The sporangiophores, sporangia containing stalks, are hyaline to slightly pigmented, sometimes branched and arising from stolons in groups of three or seven. The zygospores produced are naked with equatorial rings whose suspensors are opposed and non-appendaged. There is limited production of rhizoids, thus, it is often difficult to identify them without the assistance of a dissecting microscope.

Etymology
In 1903, Jules Vuillemin described the genus Lichtheimia under the family Mucorales, which included highly similar species L.corymbifera and L.ramosa. Common traditional methods like antifungal susceptibility can usually be used to differentiate species but in the case of these two Lichtheimia species, their susceptibility is almost indistinguishable. Therefore, comparing biological, morphological and molecular characteristics is key in the delineation of the two species. First, examining cultures of the two species showed L.corymbifera growth to be more compact whereas L.ramosa is characterized by more effuse growth. Second, L.corymbifera sporangiospores are smooth, ellipsodial and hyaline when mature compared to sporangiospores of L.ramosa that are smooth, lightly colored and more ellipsodial.

Morphology
L.corymbifera has optimal growth at human body temperature, 35-37 °C; however, due to its thermophilic nature, it can tolerate temperatures up to 50 °C. Lichthemia corymbifera is a fast growing species in both culture and in vivo. In culture, the species is pale white at germination and turns grey with age; the colonies are observed to reach up to 15 mm in thickness. In addition, L.corymbifera can be grown on bread cultures as well.

Ecology
Since L.corymbifera is a saprotrophic fungus, it is largely a decomposer. Due to this characteristic, L.corymbifera can be found all over the world in highly diverse environments. The species was first described in France in the 1900's. Since then, it has been discovered in the Middle East, Great Britain, North and South America, India, and Africa. It is commonly found in farm animals, such as cows and horses since it can grow on hay or decayed grass. Infections in farm animals can cause death relatively quickly if treatment is not administered immediately. A specific case was described in Po Valley, Italy where L.corymbifera infection caused bovine abortion.

The natural environment for L.corymbifera is soil and decaying grasses, with an optimal pH between 3.0-8.0. In addition, it has an optimal soil depth of 30-40 cm, according to a study in India. However, they can also be found in the air or underground and can survive on humans and animals, giving it its infectious quality. Furthermore, L.corymbifera can survive well in humid environments, for example, in swamps, dung, grasslands or sewage, in cotton, grains and straw as well.

Epidemiology
L.corymbifera is the only species in this genus that is disease causing. It accounts for approximately 5% of mucormycoses today, but this figure can be smaller or larger than its actual prevalence since diagnosis is based on morphology examination. Infection can occur in people with normal immune systems but contraction is rare if the person is merely in contact with infected soil. On the other hand, infection is common in individuals with weakened immune systems due to diseases like HIV/AIDS. There is a 100% mortality rate for individuals with HIV/AIDS who are infected with L.corymbifera. Other immunodeficient diseases that are susceptible to infection are diabetes, blood cancers like leukemia or large skin wounds that can be caused by burns. In patients with leukemia, the mortality rate is 1%. The specific mucormycoses caused by L.corymbifera involve deep infections of the rhinocerebral and bronchorespiratory tract and in animals can often cause mycotic abortions.

Infection is promoted in immuno-suppressed organisms through spore inhalation or direct contact of L.corymbifera spores with tissues. Upon infection, the fungus invades the blood vessels and there is nearby tissue destruction or blood clot formation. Symptoms can be seen in various organ systems. For example, if the abdomen is infected, diagnosis is difficult since it is similar to an abcess presentation. Hence, diagnosis is often only made at death. Diagnosis is also difficult if the lungs are infected. X-rays are often inconclusive in differentiating between other infections. If the sinus/craniofacial area is infected, symptoms begin with facial pain, progress to muscle or nerve impairment in the eye area, and lead to the creation of blood clots in arteries that feed brain tissue.

Treatment
Treatment involves a combination of surgical debridement and antifungal therapy. L.corymbifera is most susceptible to the antifungal drug Amphotericin B and Posaconazole, however, negative side effects are possible. These side effects can be relatively mild, resulting in chills and muscle pain but it can also result in severe forms of nephrotoxicity. Amphotericin B binds to ergosterol, found in fungal cell membranes. This causes ion and sugar leakage progressing to cell death. The species is variably susceptible to Itraconazole and highly resistant to Fluconazole, Ketoconazole, Voriconazole and Echinocandins. Higher doses must be administered for these antifungal drugs to be effective.