Modern epidemiology involves history since finding the causes of chronic diseases requires looking back for <u>decades</u>.
In the past, infectious diseases, which were the leading cause of death, were the primary focus of epidemiological research. This was especially true after the advent of urbanization when populations began to concentrate in cities. Better hygiene, vaccination rates, and antibiotics were able to put an end to the epidemics.
Epidemiology gradually evolved into the study of the causes, the distribution, the risk factors, and the prevention of chronic diseases, but it also expanded to include the study of diseases with a mass occurrence at the population level, such as depression, and accidents. The medical community has slowly come around to the idea that diet plays a significant role in overall health, but they continue to give it less weight than it deserves.
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According to the research, the correct option is Period of invasion. The stage of an infectious disease when specific signs and symptoms are seen and the pathogen is at peak activity is the Period of invasion.
<h3>What is an infectious disease?</h3>
It is the disease that is due to the invasion of the body by pathogenic germs, which establish and multiply caused by a local cell injury, secretion of toxins or by the antigen-antibody reaction.
The stage of an infectious disease called the Period of invasion is the time interval between invasion by an infectious agent and the appearance of the first signs and symptoms of the disease.
Therefore, we can conclude that according to the research, the correct option is Period of invasion. The stage of an infectious disease when specific signs and symptoms are seen and the pathogen is at peak activity is the Period of invasion.
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Answer:
fever is a common symptom that shows there is an infection in the body. many people with symptomatic coronavirus experience fever.
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Answer:
Explanation:
The osmotic gradient in the kidney typically in the medulla is a process that generates urine that is 5 times more concentrated so as to reduce the loss of water from the body.
The countercurrent multiplication is a process that uses energy to produce the osmotic gradient in the kidney, this process facilitates the reabsorption of water from the tubular fluid. This mechanism moves the sodium chloride from the tubular fluid to the interstitial space of the kidneys. The osmotic gradient can be developed in two ways:
1. The single effect: This involves the transport of sodium chloride from the tubular fluid and moved to the ascending limb then finally to the interstitial fluid. As a result of this, the water moves passively down to the concentration gradient out of the tubular fluid than to the descending limb of the interstitial space, until the equilibrium is achieved.
2. Fluid flow method: The tubular fluid enters into the descending limb. This pushes the fluid into high osmolarity typically down the tube. This way the osmotic gradient develops.
