Rhizopus is a genus of fungi that belongs to the order Mucorales and the family Rhizopodaceae. It contains about 10 species of filamentous fungi that are widely distributed in nature and can grow on various organic substrates, such as fruits, vegetables, bread, leather, and peanuts. Some species of Rhizopus are also used in industrial processes, such as the production of fumaric acid, lactic acid, cortisone, biotin, and alcoholic beverages. However, some species of Rhizopus can also cause diseases in plants and animals, such as soft rot, fruit rot, and mucormycosis .

Rhizopus fungi have a coenocytic (non-septate) mycelium composed of three types of hyphae: stolons, rhizoids, and sporangiophores. Stolons are horizontal hyphae that grow along the surface of the substrate and produce rhizoids and sporangiophores at regular intervals. Rhizoids are short, branched hyphae that penetrate the substrate and absorb nutrients. Sporangiophores are erect, unbranched hyphae that bear spherical sporangia at their tips. Sporangia are structures that contain numerous spores for asexual reproduction. The spores are multinucleate and nonmotile and are released when the sporangium ruptures .

Rhizopus fungi can also reproduce sexually by forming zygospores. Zygospores are thick-walled resting structures that result from the fusion of two compatible mycelia. Zygospores can germinate after a period of dormancy and produce new colonies that are genetically different from the parent colonies .

Rhizopus is a versatile and ubiquitous fungus that plays an important role in decomposition, fermentation, and biotechnology. However, it can also pose a threat to human and animal health if it infects susceptible hosts or contaminates food products. Therefore, it is important to understand the biology and ecology of this fungus and its interactions with other organisms.

Mucormycosis, also known as black fungus, is a rare but life-threatening infection caused by a group of molds called mucormycetes. These molds are widespread in the environment and can be found in soil, decaying organic matter, and animal dung . However, they can also infect humans and animals, especially those who have weakened immune systems or underlying medical conditions .

Mucormycosis can affect different parts of the body, depending on how the mold enters the body. The most common form is rhinocerebral mucormycosis, which affects the nose, sinuses, eyes, and brain. This form usually occurs after inhaling mold spores from the air or contaminated food . Symptoms may include runny nose, black or bloody nasal discharge, facial pain and swelling, headache, fever, blurred vision, eye bulging or displacement, and tissue necrosis (death) . If left untreated, rhinocerebral mucormycosis can spread to the brain and cause seizures, coma, and death .

Other forms of mucormycosis include pulmonary mucormycosis (affecting the lungs), gastrointestinal mucormycosis (affecting the stomach and intestines), cutaneous mucormycosis (affecting the skin), disseminated mucormycosis (affecting multiple organs), and miscellaneous mucormycosis (affecting other sites such as the kidneys, heart, or bones) . These forms can occur after inhaling mold spores, ingesting contaminated food or water, or having a skin injury that exposes the wound to mold . Symptoms vary depending on the site of infection but may include cough, chest pain, shortness of breath, abdominal pain, vomiting, diarrhea, skin ulcers or black lesions, fever, and weight loss . Disseminated mucormycosis can cause organ failure and shock .

Mucormycosis is diagnosed by taking a tissue sample (biopsy) from the infected site and examining it under a microscope or culturing it in a laboratory. Imaging tests such as X-rays, CT scans, or MRI scans may also be used to determine the extent of infection . Treatment involves a combination of antifungal drugs (such as amphotericin B or posaconazole) and surgery to remove the infected tissue and prevent further spread . Treatment may last for several weeks or months and may have serious side effects such as kidney damage or low blood counts . Even with treatment, mucormycosis has a high mortality rate ranging from 30% to 90%, depending on the type and severity of infection .

Mucormycosis can be prevented by avoiding exposure to mold spores in high-risk environments such as dusty areas, water-damaged buildings, or compost piles. People who have diabetes should keep their blood sugar levels under control and monitor for signs of infection. People who have other risk factors such as low white blood cells, cancer, organ transplant, iron overload, kidney problems, long-term steroids or immunosuppressants should seek medical attention promptly if they develop symptoms of mucormycosis . Mucormycosis is not contagious and does not spread from person to person.

Mucormycosis is a serious complication of Rhizopus infection that can affect various parts of the body and cause severe damage and death. It is important to recognize the signs and symptoms of this infection and seek timely diagnosis and treatment. Prevention measures such as avoiding exposure to mold spores and maintaining good health can reduce the risk of developing this infection.