dryness after a rainy season; this phenomenon, termed "grow and blow", refers to growth of the fungus in wet weather, producing spores which are spread by the wind during succeeding dry weather. while the majority of cases are observed in the endemic region, cases reported outside the area are generally visitors, who contact the infection and return to their native areas before becoming symptomatic. north america in the united states, c. immitis is endemic to southern and central california with the highest presence in the san joaquin valley. c. posadassi is most prevalent in arizona, although it can be found in a wider region spanning from utah, new mexico, texas, and nevada. an estimated 150,000 infections occur annually, with 25,000 new infections occurring every year. the incidence of coccidioidomycosis in the united states in 2011 (42.6 per 100,000) was almost ten times higher than the incidence reported in 1998 (5.3 per 100,000). in area where it is most prevalent, the infection rate is 2-4%. incidence varies widely across the west and southwest. in arizona, for instance, in 2007, there were 3,450 cases in maricopa county, which in 2007 had an estimated population of 3,880,181 for an incidence of approximately 1 in 1,125. in contrast, though southern new mexico is considered an endemic region, there were 35 cases in the entire state in 2008 and 23 in 2007, in a region that had an estimated 2008 population of 1,984,356, for an incidence of approximately 1 in 56,695. infection rates vary greatly by county, and although population density is important, so are other factors that have not been proven yet. greater construction activity may disturb spores in the soil. in addition, the effect of altitude on fungi growth and morphology has not been studied, and altitude can range from sea level to 10,000 feet or higher across california, arizona, utah and new mexico. in california from 2000 to 2007, there were 16,970 reported cases (5.9 per 100,000 people) and 752 deaths of the 8,657 people hospitalized. the highest incidence was in the san joaquin valley with 76% of the 16,970 cases (12,855) occurring in the area. following the 1994 northridge earthquake, there was a sudden increase of cases in the areas affected by the quake, at a pace of over 10 times baseline. there was an outbreak in the summer of 2001 in colorado, away from where the disease was considered endemic. a group of archeologists visited dinosaur national monument, and eight members of the crew, along with two national park service workers were diagnosed with valley fever. california state prisons, beginning in 1919, have been particularly affected by coccidioidomycosis. in 2005 and 2006, the pleasant valley state prison near coalinga and avenal state prison near avenal on the western side of the san joaquin valley had the highest incidence in 2005, of at least 3,000 per 100,000. the receiver appointed in plata v. schwarzenegger issued an order in may 2013 requiring relocation of vulnerable populations in those prisons. the incidence rate has been increasing, with rates as high as 7% during 2006–2010. the cost of care and treatment is $23 million in california prisons. a lawsuit was filed against the state in 2014 on behalf of 58 inmates stating that the avenal and pleasant valley state prisons did not take necessary steps to prevent infections. population risk factors there are several populations that have a higher risk for contracting coccidioidomycosis and developing the advanced disseminated version of the disease. populations with exposure to the airborne arthroconidia working in agriculture and construction have a higher risk. outbreaks have also been linked to earthquakes, windstorms and military training exercises where the ground is disturbed. historically, an infection is more likely to occur in males than females, although this could be attributed to occupation rather than being sex-specific. women who are pregnant and immediately postpartum are at a high risk of infection and dissemination. there is also an association between stage of pregnancy and severity of the disease, with third trimester women being more likely to develop dissemination. presumably this is related to highly elevated hormonal levels, which stimulate growth and maturation of spherules and subsequent release of endospores. certain ethnic populations are more susceptible to disseminated coccidioidomycosis. the risk of dissemination is 175 times greater in filipinos and 10 times greater in african americans than non-hispanic whites. individuals with a weakened immune system are also more susceptible to the disease. in particular, individuals with hiv and diseases that impair t-cell function. individuals with pre-existing conditions such as diabetes are also at a higher risk. age also affects the severity of the disease, with more than one-third of deaths being in the 65-84 age group. history the first case of what was later named coccidioidomycosis was described in 1892 in buenos aires by alejandro posadas, a medical intern at the hospital de clínicas "josé de san martín". posadas established an infectious character of the disease after being able to transfer it in laboratory conditions to lab animals. in the u.s., dr. e. rixford, a physician from a san francisco hospital, and t. c. gilchrist, a pathologist at johns hopkins medical school, became early pioneers of clinical studies of the infection. they decided that the causative organism was a coccidia-type protozoan and named it coccidioides immitis (resembling coccidia, not mild). dr. william ophüls, a professor at stanford university hospital (san francisco), discovered that the causative agent of the disease that was at first called coccidioides infection and later coccidioidomycosis was a fungal pathogen, and coccidioidomycosis was also distinguished from histoplasmosis and blastomycosis. further, coccidioides immitis was identified as the culprit of respiratory disorders previously called san joaquin valley fever, desert fever, and valley fever, and a serum precipitin test was developed by charles e. smith that was able to detect an acute form of the infection. in retrospect, smith played a major role in both medical research and raising awareness about coccidioidomycosis, especially when he became dean of the school of public health at the university of california at berkeley in 1951. coccidioides immitis was considered by the united states during the 1950s and 1960s as a potential biological weapon. the strain selected for investigation was designated with the military symbol oc, and initial expectations were for its deployment as a human incapacitant. medical research suggested that oc might have had some lethal effects on the populace, and coccidioides immitis started to be classified by the authorities as a threat to public health. however, coccidioides immitis was never weaponized to the public's knowledge, and most of the military research in the mid-1960s was concentrated on developing a human vaccine. currently, it is not on the u.s. department of health and human services' or centers for disease control and prevention's list of select agents and toxins. in 2002, coccidioides posadasii was identified as genetically distinct from coccidioides immitis despite their morphologic similarities and can also cause coccidioidomycosis. research as of 2023, there is no vaccine available to prevent infection with coccidioides immitis or coccidioides posadasii, but efforts to develop such a vaccine are underway. anivive lifesciences is currently developing a vaccine for use in dogs, which could eventually lead to a vaccine in humans. other animals a dog with coccidioidomycosis valley fever is not contagious. in dogs, the most common symptom of coccidioidomycosis is a chronic cough, which can be dry or moist. other symptoms include fever (in approximately 50% of cases), weight loss, anorexia, lethargy, and depression. the disease can disseminate throughout the dog's body, most commonly causing osteomyelitis (infection of the bone), which leads to lameness. dissemination can cause other symptoms, depending on which organs are infected. if the fungus infects the heart or pericardium, it can cause heart failure and death. in cats, symptoms may include skin lesions, fever, and loss of appetite, with skin lesions being the most common. other species in which valley fever has been found include livestock such as cattle and horses; llamas; marine mammals, including sea otters; zoo animals such as monkeys and apes, kangaroos, tigers, etc.; and wildlife native to the geographic area where the fungus is found, such as cougars, skunks, and javelinas. additional images spherule and endospore forms of coccidioides immitis mature spherule with endospores of coccidioides immitis in popular culture in the season 1 episode of bones called "the man in the fallout shelter" the entire lab is exposed to coccidioidomycosis through inhalation of bone dust. erroneously, the team is forced to quarantine in the lab on christmas eve to prevent the disease from spreading to the public (in real life, the disease is not contagious). the lab is later exposed to it again in the season 2 episode "the priest in the churchyard" from contaminated graveyard soil but only receives a series of injections rather than be forced to quarantine. everything in between, a 2022 australian feature film, contains references to coccidioidomycosis. in house season 3 episode 4, "lines in the sand", a 17-year-old patient who has been exposed to coccidioides immitis exhibits symptoms of coccidioidomycosis. thunderhead, a 1999 novel by douglas preston and lincoln child, uses the fungus and illness as a central plot point.