5.
Hay Fever, Asthma, & Valley Fever
Authors
The information in this chapter was prepared by the following individuals:
Description of Hay Fever and Asthma:
o Tim Flood, M.D., Medical Director, Chronic Disease Epidemiology Section, Arizona Department of Health
Description of Valley Fever:
o Ben Chaiken, former director, Arizona Lung Association
Hay Fever
Hay fever is caused by outdoor, airborne allergens including pollens and molds. It is a seasonal, chronic condition.
Hay fever is characterized by reddened, watery eyes, sneezing, and nasal discharge. Although not a serious condition, hay fever is often treated with over-the-counter medications and prescription drugs that cause side effects such as drowsiness and dry mouth, which are nearly as annoying.
To determine the number of persons with allergen-induced hay fever, the Committee referred to the rates produced by the National Health Interview Survey. This survey asks persons across the U.S. whether they had the condition at least twice during the past 12 months, or for a duration of one month or more.
Assuming that the rate of hay fever in Arizona is the same as the rate in the U.S., the Committee estimates that approximately 383,000 Arizonans suffered from hay fever in 1994.
In addition, allergens contribute to a significant number of new cases of asthma.
Conclusion
In conclusion, although hay fever is not a serious condition, the number of affected persons led the Committee to rank this issue high.
Environmentally Caused Asthma
Asthma is a difficult disease to study because of imprecise diagnostic criteria used by various population groups, clinicians, and researchers. In this assessment, the Committee started with the disease and worked backward to estimate the number of persons who developed asthma caused by the environment.
The Tucson Epidemiologic Study
For the past twenty years the University of Arizona has been conducting a study of respiratory diseases among the residents of Tucson. The results of this study are summarized in Table 5.1.
Table 5.1 Estimated Number Of Current Asthmatics In Arizona, 1994
---------------------------------------------------------------------------------- | Age Group | Sample Size | Number of Tucson | Arizona | Estimated | | | in Tucson | Residents with | Population, | Number of | | | | Current Asthma | 1994 | Asthmatics | | | | | | State-Wide | ================================================================================== | 0-4 | 354 | 6 | 346,065 | 5,866 | ---------------------------------------------------------------------------------- | 5-9 | 191 | 16 | 310,828 | 26,038 | ---------------------------------------------------------------------------------- | 10-14 | 246 | 21 | 293,691 | 25,071 | ---------------------------------------------------------------------------------- | 15-19 | 257 | 20 | 262,110 | 20,398 | ---------------------------------------------------------------------------------- | 20-29 | 680 | 35 | 599,773 | 30,871 | ---------------------------------------------------------------------------------- | 30-39 | 345 | 19 | 678,205 | 37,350 | ---------------------------------------------------------------------------------- | 40-49 | 303 | 18 | 522,829 | 31,059 | ---------------------------------------------------------------------------------- | 50-59 | 467 | 29 | 344,741 | 21,408 | ---------------------------------------------------------------------------------- | 60-69 | 536 | 34 | 302,174 | 19,168 | ---------------------------------------------------------------------------------- | 70+ | 481 | 34 | 376,395 | 26,606 | ---------------------------------------------------------------------------------- | All Ages | 3,860 | 232 | 4,036,811 | 242,627 | ----------------------------------------------------------------------------------
The University of Arizona study estimates the number of asthmatics in Arizona to be 242,627. This figure, which includes about one out of every 16 Arizonans, shows that the prevalence rate of asthma is somewhat higher in Arizona than in other parts of the U.S.
It is believed that the elevated rate is caused by asthmatics who move to Arizona hoping that the climate will improve their disease. Arizona's higher prevalence of asthma also may be attributed to offspring who have a higher predisposition of developing it.
National Health Interview Survey
The estimated 242,627 asthmatics in the University of Arizona study is similar to estimates that use data from the National Health Interview Survey (Benson and Marano, 1994).
Using the National Health Interview Survey rates, which were developed from a survey of the entire U.S., the Committee estimates that 198,955 Arizonans would claim that they had asthma during the past 12 months.
These two figures are fairly similar, but reflect the slightly higher number of cases estimated by the University of Arizona study in Tucson.
The Committee's application of this rate statewide may slightly overestimate Arizona's cases because the rate among American Indians is probably lower than among whites. Rates among Hispanics tend to be similar to the rates among whites.
The number of cases among African-Americans, which are about 3% of the state population, would not significantly change the statewide estimate, and was not factored into the calculations.
Causes of Asthma
As with many diseases, the underlying cause of asthma is difficult to identify.
Experts in pulmonary medicine have differing opinions about what causes it, but most would agree that asthma is caused by an external agent in a genetically- susceptible or predisposed individual. Identifying the responsible agents or the specific genes, however, has proven very difficult.
When symptoms occur in a predictable and seasonal pattern then we can be fairly certain that the asthma is caused by pollens of grasses, trees, or other plants.
Viral infections can also lead to asthma as can, in rare cases, exposure to isocyanates used in the manufacture of plastics and foams.
Asthma usually begins in childhood, but can arise in adulthood. It can be outgrown or simply disappear for unknown reasons.
Table 3.2 presents the Committee's best professional calculations about the causes of asthma and the number of prevalent cases in Arizona.
Table 5.2 Initial Cause Of Asthma
------------------------------------------------------------------------------- | Initial Cause | Proportion of | Number of | | | Cases | Prevalent | | | | Cases | | | (%) | | =============================================================================== | Viral Infection | 5 | 12,131 | ------------------------------------------------------------------------------- | Environment | 90 | -- | ------------------------------------------------------------------------------- | Allergens | 80 | 194,101 | ------------------------------------------------------------------------------- | Air pollution | 10 | -- | ------------------------------------------------------------------------------- | Environmental Tobacco Smoke | 5 | 12,131 | ------------------------------------------------------------------------------- | HAPS, Fine Particulates & Other Chemicals | 5 | 12,131 | ------------------------------------------------------------------------------- | Unknown | 5 | 12,131 | ------------------------------------------------------------------------------- | Total | 100 | 242,627 | -------------------------------------------------------------------------------
Airborne allergens include agents found in the outdoor environment. This includes many types of pollens and molds.
Airborne allergens also include agents found in the indoor environment. This includes pollens, molds, mites, and animal dander from dog and cat hair.
The underlying factors that cause a person to become an asthmatic may differ from the factors that trigger an asthmatic attack in a person who already has asthma.
Factors that can exacerbate or trigger an attack in an asthmatic include the following: airborne allergens, air pollution, cold air, respiratory infections, exercise, and stress.
Conclusion
The Committee believes that environmental factors initiate about 90% of Arizona's estimated 242,600 cases of asthma.
These factors include allergens, accounting for 80% of the cases, and air pollution, accounting for 10% of the cases.
Valley Fever
Airmen from other parts of the U.S. and from foreign countries were sent to Arizona for training during World War II. They were decimated by a strange malady so severe that not only was their training as fighting men jeopardized, so was their health.
Research discovered the culprit to be an indigenous southwestern desert fungi called coccidioides immitis.
When inhaled into the lungs, the fungus causes an infection, commonly known as Valley Fever. The infection results in fever, cough, aches, possibly body rash and other symptoms typical of respiratory disease.
Fortunately, in the majority of those inflicted, Valley Fever is a benign, self-limiting disease, not unlike flu. The prevailing medical opinion is that, upon recovery, individuals are immune from contracting Valley Fever again.
A small percentage of persons who acquire the disease may develop serious illness which may linger over weeks and months. Among individuals with compromised immune systems or dark skin, the disease may occasionally be life-threatening. Similarly, persons with occupations requiring the removal or alteration of desert soil are at greater risk of acquiring Valley Fever.
Infection is determined by skin tests, blood serology and chest x-rays. A positive skin reaction indicates that there is a past or present infection. More than 40% of all persons who come to Arizona will develop a mild case of Valley Fever resulting in a positive skin test within two years of immigrating.
Valley Fever is not a communicable disease. It is an infectious disease which occurs upon inhalation of Valley Fever spores.
Since the organism causing Valley Fever is indigenous to the southwestern desert soil, Valley Fever is endemic in Central and Southern Arizona. It is not found in agricultural soils above 4,000 feet in altitude.
Being a form of plant life, the organism proliferates in the soil when it rains. Once moisture percolates below the surface, the top layer of desert soil becomes rich with the fungus.
The desiccated soil is easily aerosolized through winds, disturbances and other phenomena, causing the air to be laden with Valley Fever spores which are readily inhaled by the populace.
Before now, Valley Fever cases occurred mainly after rainy seasons. There seems to be a subtle change in the epidemiology of the disease which may be due to the endless wetting of soils by builders to control dust.
Arizona's popularity as a vacation spot has resulted in Valley Fever cases outside of the endemic area in many other states and foreign countries. Since the disease is not seen in these areas, it constitutes a significant diagnostic problem for health care practitioners.
Additionally, since Valley Fever is an endemic disease restricted to the southwest desert, it does not receive federal research funds granted to ubiquitous diseases.
Just as do humans, long-boned dogs such as hounds and danes, and flat-nosed dogs such as boxers acquire Valley Fever. Primates are equally susceptible to contracting the disease to such an extreme that they commonly succumb to it.
Typically, fungus diseases are not as easy to treat as are bacterial diseases. The medical tools to treat Valley Fever are, at best, severely limited. Recently an experimental vaccine was used in field trials with virtually no success.
It must be mentioned, however, that since Valley Fever is a benign, self-limiting disease, treatment to ease the symptoms is routinely given. Because of the toxicity of the fungicides, they are reserved only for those persons whose disease is progressing and worsening, and whose lives might be threatened.
Although Valley Fever is a reportable disease in Arizona, it is substantially under- reported.
Arizona must be vigilant about this disease. Since the organism is indigenous, and the disease is endemic, substantial numbers of residents, new arrivals, and visitors will continue to be affected by Valley Fever.