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Viruses, Pathogens, and Other Contaminants
Published in James N. Seiber, Thomas M. Cahill, Pesticides, Organic Contaminants, and Pathogens in Air, 2022
James N. Seiber, Thomas M. Cahill
Coronaviruses are one of many classes of diseases that can be transmitted through air. For example, coccidioidomycosis is a fungal infection caused by inhaling the spores of either Coccidioides immitis or Coccidioides posadasii fungi. These spores are endemic to the soils of the American Southwest and can get into the air when the soil is disturbed—for example, via wind, construction, gardening, or farming (American Thoracic Society, 2011). Like coronaviruses, the severity of the infection is largely dependent on the degree of exposure to the spores, along with the health of the victim’s immune system. A severe infection can lead to “Valley Fever,” a dangerous and sometimes fatal disease (as one of the authors experienced firsthand while a graduate student at Arizona State University and Utah State University). Another disease that can be transmitted through air is Legionnaires’ disease—a severe form of pneumonia. Caused by the legionella bacterium, Legionnaires’ disease comes from inhaling the bacteria from water or soil (Mayo Clinic, 2019). As suspected with COVID-19, the degree of exposure is correlated with the severity of the illness. In the summer months, malfunctioning air conditioning equipment can be a breeding ground for the bacteria and lead to prolonged exposure in hotels in the Southwest—much as air conditioning appears to be a mechanism for contaminating an airspace with coronaviruses.
Biological Analysis of Fungi and Associated Molds
Published in Christopher S. Cox, Christopher M. Wathes, Bioaerosols Handbook, 2020
Coccidioidomycosis is a highly infectious disease caused by inhalation of airborne arthrospores of the dimorphic fungus Coccidioides immitis. The disease is endemic in certain regions, principally in desert soils in North America, and reportedly affects man, monkeys, dogs, cattle, rodents and rarely, cats, horses, sheep and swine. It causes initial respiratory infection that occasionally progresses to the disseminated, highly fatal form. Evidence of infection by the airborne route has been demonstrated at an endemic site in Southern Arizona, where the disease was acquired by 5 out of 34 monkeys confined in open cages suspended above ground level for one year, although the fungus was not isolated on exposed plates of culture medium.94 Large-scale skin-test programs using extracts of the fungus have been used to assay geographic boundaries of the disease. These also revealed the extensive incidence of the mild, self-limiting form. IgG and IgM precipitating antibodies to coccidioidin develop after infection, and complement-fixing antibodies also arise. Clinical material should be inoculated onto cycloheximide-chloramphenicol agar that selectively isolates C. immitis from almost all other bacteria and saprophytic fungi. The dangers of inhaling airborne arthrospores of the mold form of the fungus can be eliminated by inoculating suspected clinical material into mice for subsequent histological examination.
Microbiological Hazards
Published in Dag K. Brune, Christer Edling, Occupational Hazards in the Health Professions, 2020
Coccidioidomycosis is a disease acquired by the inhalation of the arthrospores of C. immitis of environmental origin. The natural infection is largely confined to the southwest part of the U.S., Central America, Venezuela, Colombia, Paraguay, and Argentina.383 Coccidioidomycosis does not spread from person to person, and there is for all practical purposes no risk of secondary infection of health care personnel providing bedside care for patients with the disease. One exception to this rule was reported by Eckman et al.,384 although strictly speaking, this was a case of transmission via growth on a fomite. The dressings and plaster cast of a patient with draining coccidial osteomyelitis was contaminated with spherules of C. immitis. These germinated on the plaster cast forming arthrospores, resulting in six cases of primary pulmonary infection among personnel involved in changing dressings. In addition, there were considerably more reactors to the coccidioidin skin test among 78 possibly exposed personnel (19.4% positive) than among 38 nonexposed individuals (5.3% positive).
Occupational Coccidioidomycosis in a heavy equipment operator
Published in Journal of Occupational and Environmental Hygiene, 2018
Coccidioides immitis (hereafter termed C. immitis) is a soil fungus endemic in certain areas of California, most notably in the California San Joaquin Valley.[1–3] A related pathogenic fungal species C. posadasii is endemic in areas of Arizona, New Mexico and Texas.[3]C. immitis is not found uniformly across a land terrain, but occurs in isolated pockets termed foci. When infected soil is disturbed, soil particles and respirable spores become airborne. The greatest likelihood for spore inhalation is among individuals closest to the point of soil dust generation. Spore inhalation leads to an infection termed Coccidioidomycosis, more commonly known as Valley Fever. The infection is usually limited to the respiratory tract, although the fungus can disseminate from the lungs into other body tissues. Pulmonary infection is asymptomatic in about 60% of individuals, and initially causes influenza-like symptoms in the remaining 40% of those infected.[3,4] The infection usually resolves without medical treatment but can last for several weeks. The pulmonary infection can progress to pneumonia, for which an anti-fungal drug is usually prescribed.[4,5] Limited animal research indicates that the likelihood of pneumonia increases with the dose of spores inhaled.[6] In less than 1% of White Americans who are infected, the fungus disseminates outside the lungs and can spread to bones, joints, skin and soft tissues. The percentage in whom dissemination occurs is higher among those of African and Filipino descent, and among persons who are immuno-suppressed.[5]