#epidemeology

[mikeo56]

Welcome to Science Matters: Let's talk COVID-19

Imperial College London- Free Online Course- Based in real time adjusted as changes in the pandemic occur

Please note that we are creating all the content in real time as new information emerges, and that new material will be uploaded as it becomes available. The contents of the course are available free of charge.

[dgm885]

Theories that diseases are caused by mental states and can be cured by will power are always an index of how much is not understood about the physical terrain of a disease.

Susan Sontag, Illness as Metaphor (1978)

[performancespace]

During the Boston Medical Intern Strike in 2012, the striking soon-to-be physicians, surgeons, and specialists sought to find ways to keep being medically useful—both to prevent patients from suffering during the strike, and to forestall claims that the strikers were greedy, rather than exploited. General practitioners, family doctors, and the like were able to help at free clinics, but those studying to work in more specialized fields had to be inventive. A group of epidemiologists, morticians, and public health officers addressed the dilemma by staging a play about the first mortality studies, compiled by John Graunt during the 17th century. A straightforward piece of hagiography in its first draft, the spirit of the strike drew the group to focus more and more on the "Searchers," the long-ignored older, lower-class women who recorded fatalities for church records—the records Graunt used in his reports. While still impressing the importance of public health measures to the viewing public, its scenes of their gruesome daily task—with bodies strewn across the grass at the height of plague outbreak—inspired sympathy for the striking group's work. The climactic confrontation with John Graunt following his challenging the veracity of their work, meanwhile, led many to question the motivations and probity of Boston's medical research community for years to come.

[23pairsofchromosomes]

The Bacteria of the London Underground

If you’ve ever been to London, then you’ve probably at least heard horror stories of the cramped and uncomfortable conditions that Londoner’s are faced with when the tube lines are busy. However the person who just stuck a sweaty armpit in your face isn’t the only cause for concern on the underground.

More than 1.34 billion passengers ride the tube each year, and each of them transport millions of bacteria on their journey. All of that human movement provides a perfect transport system for these little bugs to travel rapidly from one part of London to another within minutes. Should we be worried about what health problems this may pose?

Well a team was sent into the underground to swab surfaces to uncover what monstrosities lurk down there. The image above shows the results of their findings. The line that comes out on top of all others is the Northern line, harbouring 1,647 CFU/10 cm^2. This means that for every 10 cm^2, over 1,600 viable bacterial cells were happily surviving and making themselves at home. This was nearly three times as many bacterial cells than seen within the central line, which came in second place.

The team also looked at identifying the most contaminated tube stations. Stratford was found to take home the gold, although it is only the 7th busiest station in London.  

They also found that the most bacteria contaminated surfaces were unsurprisingly the surfaces that are in contact with a lot of humans on a daily basis. This included: the ticket machines, the barriers, the seats, escalators, and the metal poles within the tubes themselves.

So what does this all mean for you commute home? There is probably no need to run out and buy hand sanitiser. In reality, we’re surrounded by bacteria all the time, and just because the tube has high levels of viable cells does not necessarily mean that all of these organisms are bad for you. This study only quantified what was growing in the depths of the underground and did not identify probable disease causing species. That being said, the group do still recommend that you maintain good personal hygiene on a daily basis to ensure that you do not contract anything nasty.

Read more: Mind the Germs

[brainsandbodies]

AIDS is not spread by insects

AIDS largely affects those in their most productive years, around 20’s-40’s. The age of those most bitten by insects like Mosquitos are the very young and the elderly.

AIDS largely affects those in Urban areas, while insects like Mosquitos largely populate rural areas.

While yellow fever and other diseases can be transferred by insects, there is no evidence for similar transmission with AIDS.

Source: AIDS and society textbook

Note, HIV is the agent that causes AIDS (which is the name for the late stage of infection), I used them interchangeably but there is a distinction

[pathologyfornurses-blog]

1.1 modern perspectives on individual and population health

health is determined by many factors, including genetics, age and sex, and cultural and ethnic differences. The WHO defines health as a “state of complete physical, mental, and social well-being and not merely the absence of disease and infirmity.”

The ability of the body to adapt to changes that occur in both health and disease is affected by such factors as age, health status, and psychosocial resources. Adaptation is further affected by the availability and number of adaptive responses. Extreme age and disease conditions, such as when changes occur suddenly rather than gradually, also affect the capacity to adapt.

The term pathophysiology may be defined as the physiology of altered health. A disease has been defined as any deviation from or interruption of the normal structure or function of any part, organ, or system of the body that is manifested by a characteristic set of symptoms or signs and whose etiology, pathology, and prognosis may be known or unknown.

The causes of disease are known as etiologic factors. Recognized etiologic agents include biologic agents (bacteria, viruses), physical forces (trauma, burns, radiation), chemical agents (poisons, alcohol), and nutritional excesses or deficits. Pathogenesis describes how the disease process evolves. Morphology refers to the structure or form of cells or tissues; morphologic changes are changes in structure or form that are characteristic of a disease.

Disease can manifest itself through signs and symptoms. A symptom is a subjective complaint, such as pain or dizziness; a sign is an observable manifestation, such as an elevated temperature or a reddened sore throat. A syndrome is a compilation of signs and symptoms that are characteristic of a specific disease state. The clinical course of a disease describes its evolution. It can be acute (relatively severe, but self-limiting), chronic (continuous or episodic, but taking place over a long period), or subacute (not as severe as acute or as prolonged as chronic).

Within the disease spectrum, a disease can be designated pre-clinical, or not clinically evident; subclinical, not clinically apparent and not destined to become clinically apparent; or clinical, characterized by signs and symptoms.

the health of individuals is closely linked to the health of the community and to the population it encompasses. Epidemiology is the study of disease in populations. It looks for patterns such as age, race, and dietary habits of persons who are affected with a particular disorder to determine under what circumstances the particular disorder will occur. Using epidemiologic methods, researchers determine how a disease is spread, how to control it, how to prevent it, and how to eliminate it.

Epidemiologists use measures of disease frequency to predict what diseases are present in a population and as an indication of the rate at which they are increasing or decreasing. Incidence is the number of new cases arising in a population during a specified time. Prevalence is the number of people in a population who have a particular disease at a given point in time or period.

Morbidity and mortality provide epidemiologists with information about the functional effects and death-producing characteristics of a disease. Mortality or death statistics provide information about the trends in the health of a population. Morbidity describes the effects an illness has on a person’s life.It is concerned with the incidence of disease as well as its persistence and long-term consequences.

Conditions suspected of contributing to the development of a disease are called risk factors. They may be inherent to a person (high blood pressure) or external (smoking). Studies used to determine risk factors include cross-sectional studies, case-control studies, and cohort studies. Cross-sectional studies use the simultaneous collection of information necessary for classification of exposure and outcome status. Case-control studies are designed to compare subjects who are known to have the outcome of interest (cases) with those who are known not to have the outcome of interest (control). Cohort studies involve groups of persons who were born at approximately the same time or share some characteristic of interest.

The natural history of disease refers to the progression and projected outcome of a disease without medical intervention. It can be used to determine disease outcome, establish priorities for health care services, provide direction for prevention and early detection programs, and compare treatment methods and their outcomes with untreated outcomes. Prognosis is the term used to designate the probable outcome and prospect of recovery from a disease.

The three fundamental types of prevention are primary prevention, secondary prevention, and tertiary prevention. Primary prevention, such as immunizations, is directed at removing risk factors so that disease does not occur. Secondary prevention, such as a Pap smear, detects disease when it still is asymptomatic and curable with treatment. Tertiary prevention, such as β-adrenergic drugs to reduce the risk for death in persons who have had a heart attack, focuses on clinical interventions that prevent further deterioration or reduce the complications of a disease.

Evidence-based practice and evidence-based practice guidlines are mechanisms that use the current best evidence to make decisions about the health care of individuals.