Epidemiology and Valley Fever

Dream Job Turned Nightmare: Valley Fever Executive Summary According to the Centers for Disease Control and Prevention (CDC, 2018a), coccidioidomycosis, also known as Valley fever, is an infection caused by the fungus Coccidioides. The fungus is commonly found in the soil in the Southwestern U.S. and Mexico region. When people breathe in the spores of the fungus, which can hang in the dusty air, they can develop Valley Fever. People who already have weakened immune systems are most likely at risk for developing Valley Fever (Woods et al., 2000).

Those with healthier immune systems tend to recover within a few weeks, though sometimes it can take months to heal completely and antifungal medication may be provide for treatment. This paper describes how descriptive and analytical epidemiology can be used to provide a response plan for the disease.

Purpose Statement The purpose of this paper is to provide a discussion on why the fact that several patients have tested positive for coccidioidomycosis is an epidemiological problem, what approach the epidemiologist would take to addressing the issue, and how to develop an outbreak response plan. A Problem for the Field of Epidemiology Epidemiology is a field in medicine that deals with the incidence, distribution, and potential control of diseases.

Valley Fever is a problem for the field of epidemiology because the rate of incidence is so high and control of the disease is so difficult given the manner in which it is contracted.

According to the CDC (2018b), there were 14,364 cases of Valley Fever reported in 2017, and “most of these cases were in people who live in Arizona or California, [where] rates of Valley Fever are typically highest among people age 60 and older.” It is estimated, moreover, that Valley Fever is responsible for approximately 30% of all pneumonia-related cases in the region each year, though researchers have argued that the actual rate may be even higher since testing rates are so low and infrequent themselves (Valdivia et al., 2006).

Additionally as McCotter et al. (2019) note, “the incidence of reported coccidioidomycosis in the past two decades has increased greatly; monitoring its changing epidemiology is essential for understanding its burden on patients and the healthcare system and for identifying opportunities for prevention and education” (p. 958). Valley Fever is difficult to diagnose and treat, and because of the high rate of incidence and distribution, its impact on health and the health care system, the potential control of Valley Fever does pose a problem for the field.

Prevention, as always, is the best medicine—and that applies in the case of the spread of Valley Fever no less than in other situations. Approach The epidemiological approach to take for addressing the issue of Valley Fever is to look at trends, the overall burden of disease, and the geographical risk associated with the spread of coccidioidomycosis. As the disease has recently appeared in Washington State, a fresh look at these elements has to be undertaken. Cairns et al.

(2000) linked the outbreak in Washington State to a group of travelers to Mexico who returned home; however, this has not been an isolated case and Litvintseva et al. (2014) have shown that though epidemiologic data “suggested that Coccidioides might have been acquired from the local environment, all 3 case-patients [in Washington State] had traveled to endemic regions several years prior to infection; therefore, the possibility of reactivation of latent infection could not be excluded” (p. e1). Litvintseva et al.

(2014) collected soil samples, which showed that the fungus was indeed in the soil in Washington. The researchers argued that it was possible that Coccidioides “has been present in WA for an extended time, but because of low human population density in eastern WA, sporadic distribution of the pathogen, and lack of awareness among physicians, human cases of coccidioidomycosis have not been previously recognized in WA” (Litvintseva et al., 2019, p. e2). To understand the reality of the fungus, a proper epidemiological approach is therefore necessary.

Surveillance is a top priority in any epidemiological approach. Laboratory tests are used to confirm cases and incidence of the disease is recorded, monitored and analyzed. Severity, seasonality, geographical associations and so on are all examined during surveillance. Interviews with people who have been infected can be helpful in obtaining additional information about their habits, practices, recent travels and so on. This gives a clearer idea of where the patients had been prior to infection and where they might have acquired the infection.

Surveillance Methods As Thacker, Parrish and Trowbridge (1988) note, epidemiological surveillance is defined as “the systematic collection, analysis and dissemination of health data for the planning, implementation and evaluation of public health programmes” (p. 11). Factors for evaluating surveillance methods should include: 1. sensitivity 2. specificity 3. representativeness 4. timeliness 5. simplicity 6. flexibility and 7. acceptability  The purpose of surveillance is to provide assistance in establishing either prevention or control of the disease.

In the case of controlling or preventing coccidioidomycosis, a flexible surveillance method should be implemented so that regional data can be compared with random-sample data and new population groups can be added, as may be the case in the northwestern portion of the United States, following evidence of coccidioidomycosis in the region. Concepts of Descriptive and Analytic Epidemiology that Apply Descriptive epidemiology refers to the examination of patterns as they pertain to the occurrence and incidence of disease: its focus is on the who, what, when, where, why and how.

The purpose of descriptive epidemiology is to provide context for determining how a public health response should be developed and implemented. Those who practice public health typically conduct a descriptive epidemiological study in their region so as to construct a hypothesis for future analysis. One of the most famous epidemiological cases is that of the cholera outbreak in London and the work of John Snow in identifying the who, what, where, when and why—ultimately leading to the identification of ground zero of the outbreak and the bacterial cause.

Analytic epidemiology is different in that it focuses more on the complexities of the disease, such as associated risks, causes, and exposure and one of the main ways in which this is achieved is by comparing groups. If descriptive epidemiology is useful for developing hypotheses about a disease, analytic epidemiology is useful for testing those hypotheses. For this study, the descriptive epidemiological approach would look at who was infected, when, and where. A hypothesis would be constructed offering an idea of why and how the individual was infected.

That hypothesis would be tested using analytical epidemiology. A randomized-controlled trial could be conducted or an observational study could be conducted. In this case, both descriptive and analytical epidemiology would be useful, especially as the spread of the disease or at least the finding of the disease in Washington State in recent years suggests that more is unknown about it than before and a new hypothesis is required. Since a new hypothesis is required, a new test is also required—thus both approaches should be useful.

Data System Data systems in epidemiology are used to collect data and analyze it. Data collection methods can include surveys, randomized-controlled trials, and interviews. The data system is an integral part of epidemiology because it allows the researcher to gather, record and then analyze data using computer modeling, statistical analysis, regression models, and so on. Characteristic sampling could be conducted in one system and compared to randomized sampling in another.

As the National Academies of Sciences, Engineering and Medicine (1997) note, “a data-collection system can be either a compendium or a systematic survey. That is, it can consist of individual studies with similar but separate research designs and measurements, or it can collect data from many sources in a standardized fashion.” Studies are therefore the primary way in which information about the disease can be obtained, and study comparisons are helpful for understanding trends.

Secondary Surveillance Secondary surveillance is the examination of data that has not been collected for the purposes of research.

The types of data often included in secondary surveillance include: 1) information pertaining to management 2) information pertaining to claims 3) information pertaining to administration and planning 4) information pertaining to the evaluation of activities within health care 5) information pertaining to control functions 6) information pertaining to surveillance or research These secondary sources of data typically provide opportunities for secondary surveillance because they provide alternative data sources that can be used to triangulate data relevant to the field of epidemiology (Sørensen, Sabroe & Olsen, 1996).

The use of secondary surveillance can add knowledge that primary surveillance did not provide—i.e., details about the individual cases that give more context and that can lead to the identification of other variables. Secondary surveillance that would be helpful in this case would be all information pertaining to how patients were treated or diagnosed, how claims were made, how they were managed, when they were processed, what controls were used, and what prior surveillance was conducted.

This would be helpful in this case because it would provide additional context to understanding how the disease spread, if it did, from the southwest to the northwest. Deciding Whether It is an Outbreak or Not To determine whether an outbreak is occurring with this disease, the case definition has to be established. That will set the parameters for what is being discussed and researched. Second, the cases have to be shown that they are in fact real and do represent the spread of a disease.

Third, the rate of incidence has to be determined, which means background information has to be collected about the rate at which the disease has appeared in a given area. Fourth, cases have to be identified, and if there is a large, unusual appearance of incidences, it may be determined that an outbreak is occurring or has occurred. To make this determination, the epidemiological character of the cases has to be determined and compared to prior case studies.

For this particular case it would not appear that an outbreak has occurred as the disease is relatively common in the southwest and the appearance in the northwest appears to be relatively isolated. However, the potential for outbreak does appear possible and an examination of the problems related to the prevention of the spread of the disease should be undertaken. This requires its own series of steps, which can be defined in the outbreak response plan.

Steps in Development of an Outbreak Response Plan First, identify what could cause an outbreak of Valley Fever. In the past, outbreaks have coincided with earthquakes, windstorms, and even military training exercises—all of which have the potential to disrupt the soil and spread the fungus in the air so that it is inhaled by many people (Brown, Benedict, Park & Thompson, 2013). This will allow for a prevention or response plan to be developed appropriately.

Second, in the event of an outbreak or in the event of foreknowledge of an event that could trigger an outbreak, appropriate warnings should be provided to the public to remain indoors or to wear breathing masks if they must be out of doors in the immediate time frame at which infection is most likely. This will be serve to prevent the spread of infection and to limit the risk of infection at times in which outbreak is most likely to occur.

Third, persons with known weak immune systems should be immediately contacted and monitored for safety so as to prevent the individual from developing pneumonia. People with known weak immune systems should have contact information up to date and on file with health care records for this purpose. To control for the.