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Edward Jenner (1749-1823) his revolutionary contribution to vaccination and ultimate eradication of smallpox is well renowned around the world. The work of Jenner is widely regarded as the basis of immunology. Between the fifth and sixth centuries, smallpox was introduced in Europe, and later it was spread in South America by Spanish and Portuguese conquistadors and it destroyed the native populations . The sweeping of smallpox to the continent was eventually led in the fall of the Aztec and Inca empires. In the 18th century, smallpox was widespread in Europe around 60% of all infected persons, and 80% of infected children died. Survivors frequently experienced some degree of enduring scar and loss of organs (such as lips, nose, or ear tissue) smallpox is responsible for blindness also. Jenner’s method of vaccination against smallpox became popular and it eventually replaced variolation, which had been the standard before his demonstration . At the end of the 20* century (around 150 years, after Jenner’s death in 1823), after a huge surveillance and vaccination program, smallpox would eventually be eradicated.
THE BIRTH OF ANESTHESIA
In 1846, an American dentist, William Morton, demonstrated that ether causes complete absolute insensitivity to pain while an operation performed in front the doctors and students at the Massachusetts General Hospital  Morton used ether vapor to sedate the patient, without pain he was able to remove a tumor from the patient’s neck. Ether was one of the main anesthetics, but it caused the patients to be choking and also had administration difficulties. Ether anesthesia, however, supplied the patient with an enhanced surgical experience. It also enabled physicians to develop more advanced surgical skills. In November 1847, Chloroform was established by James Simpson who was a Professor of Obstetrics in Edinburgh . This was a more effective agent but it had serious side effects such as sudden death [in the case of n very anxious patients] and it also caused severe liver damage. In 1860, Albert Niemaim isolated cocaine, which thus became the first local anesthetic. Newer, less toxic, local anesthetic agents were established in the early 1900s .
th CENTURY: THE RISE OF SCIENTIFIC MEDICINE
1.5.1 INTRODUCTION OF BACTERIOLOGY AND GERM THEORY OF DISEASE
Research on disease prevention has grown enormously in the 19* century. Instruments such as the stethoscope and machines such as the electrocardiogram were also invented. Antoni van Leeuwenhoek (1632-1723) developed the most powerful microscopes that had discovered micro-organisms [protozoans and bacteria] . Consequently, his work resulted in the understanding of disease causes such as Black Death. In the late 1800’s and early 1900’s many scientific developments especially in the field of microbiology, this translational period led by the discoveiy of Louis Pasture (1850) later in 1880 this research was successively expanded by Robert Koch as the germ theory of diseases .
Pasture discovered aerobic and anaerobic organisms and initiate to think about the possibility of a causal relationship between germs and diseases. The germ theory facilitated the detection of actual microorganisms that causes several diseases. The great achievement of Pasteur was the discoveiy of a vaccine for rabies . Pasteur developed a vaccine for rabies which was capable to be injected in the period after the dog bite and before the onset of symptoms. He showed how the diseases in both animals and people could be cured by vaccination. Pasteur’s work has been implemented as the germ theory of disease and put a conclusion to different speculations of sickness, such as the humoral theory .
Robert Koch was a scientist from Germany. In molecular biology, he developed essential techniques used to find treatments and to look for the cause of ТВ. In 1905, this work got the Nobel Prize. Koch discovers the bacillus bacteria responsible for anthrax; also, he was able to demonstrate that the disease was transmissible in mice. Koch also established an innovative method to producing pure cultures of different types of bacteria by placing the bacteria on a solid culture medium. He used new aniline dyes to distinguish between different kinds of bacteria. The unproved microscope and better techniques for producing pure cultures of bacteria, Robert was able to find a tiny bacterium which he called the tubercle bacillus. The tubercle bacillus was much tinier than anthrax the bacteria. Later he discovered other bacteria that caused Cholera .
Pasteur instigated the germ theory of disease and Koch, turn it into science as bacteriology. Koch developed the techniques for the study of microorganisms and identified their relationship with specific diseases. Koch formalized four postulates to confirm an organism was the cause of a disease. These postulates of Koch are essential because they were one of the first techniques used by physicians to determine the cause of a disease .
The modified germ theory opens the new prospects for the infectious diseases control with improved diagnostic methods and provides an insight into the significance of vectors with respect to the transmission of diseases and understanding of the carrier states.
Doctor Joseph Lister (1827-1912), a surgeon at the Royal Infirmary in Glasgow, Scotland, used antiseptics for the first time. In 1867, Lister initiated to clean the surgical tools with carbolic acid [phenol], and soaked bandages were also used directly on wounds. At that period, even a tiny wound that got infected could cause death. Patients who had surgery also suffered with the risk of infection. The advancement of Dr. Lister started this new practice
TABLE 1.1 Disease-Causing Microorganism and the Year of Identification
that led to clean and sterile surgery and wound care that saved millions of lives. Lister inspired by Louis Pasteur’s work proving “germ theory,” and the causes of infections, in 1865. Lister published his work in 1867 in a paper entitled On the Antiseptic Principle in the Practice of Surgery. The germ theory was not widely accepted until the late 1890s. By 1900, it was finally routine practice for doctors to wash their hands, sterilize their tools, clean wounds, and keep operating rooms clean .
™ CENTURY: ADVANCES IN CLINICAL PRACTICE
More progress has been produced in medicine and health improvement in the 20th century than in the past 5,000 years. The causes of so many diseases were found in the 20th century and the large number of diseases could be able to prevented or cured by the 21 century. The discoveries and developments that changed the face of medicine in all respect. The improvement in the standard of living, education, diet, and nutrition, and the development of health care services the establishment of a free National Health Service, etc., has helped improve public health. Progress in science and technology led to the imiovations of new techniques and utensils for diagnosing and treating disease. Disease prevention was the prime reason of the average life expectancy increased enormously from 47 to 75 years .
Initial focus persisted on disease control during the first half of the 20th century, as well as significant achievements in endocrinology, nutrition, and other related areas were also accomplished. Fundamental concepts of the disease process altered in the years after World War II by knowledge of cell biology. New biochemical and physiological achievements opened the way for accurate diagnostic tests, more effective therapies, and treatments. Stupendous developments in biomedical engineering enabled the doctor and specialist to test the structures and functions of human body using non-inva- sive imaging methods, for example, ultrasound (sonar), computerized axial tomography (CAT), and nuclear magnetic resonance (NMR). With each new logical improvement, therapeutic practices of only a couple of years sooner ended up outdated.
1.6.1 INFECTIOUS DISEASES AND CHEMOTHERAPY
Continuing research in the first half of the 20th century concentrated mainly on the nature of infectious diseases and their mode of transmission . Different types of pathogenic organisms were discovered and classified. Diseases like typhus fever caused by rickettsias, are highly pleomorphic bacteria that may occur in the foims of cocci 0.1 pm in diameter, rods 1-4 pm long, or threads up to about 10 pm long and are smaller bacteria. Other pathogenic organisms like protozoans are unicellular eukaiyotes relatively complex internal structure and carry out complex metabolic activities. Protozoans causing tropical diseases including malaria [there are four species that infect humans: P. vivax, P. ovale, P. malariae, and P falciparum] The viruses are smallest pathogenic organisms causing many diseases, German measles mumps, measles, polio, and malignant tumor [Rous sarcoma Virus], Chemotherapy was launched in the early 20th century. Chemotherapy was pioneered by Gennan scientist Paul Ehrlich (1854-1915) . He introduced the term chemotherapy and studied substantial quantities of chemicals to evaluate their efficacy in treating infectious diseases and he defined the successors as “magic bullets.”
1.6.2 DEVELOPMENT OF ANTIBIOTICS
With his invention of enzyme lysozyme (1921) and antibiotic penicillin (1928), Sir Alexander Fleming, a Scottish biologist, defined new horizons for modem antibiotics . In 1929, Fleming published his results and then in a briefer report in 1932. Fleming’s work was largely ignored at the time because as per the main scientific view, the use of antibiotic drags would not work against infectious disease and would be toxic to use on humans. In 1944, penicillin was commonly used to treat infections of soldiers. It was widely used in the battlefield as well as in hospitals across Europe. Penicillin had been nicknamed ‘the wonder drag’ by the end of World War II and had saved many lives. Howard Florey and Ernst Chain (Scientists in Oxford) have succeeded in effectively purifying and the large scale manufacture of penicillin. The emergence of penicillin was considered as the beginning of “golden era” of antibiotics . In 1945, Ernst Boris Chain and Sir Howard Walter Florey they shared the Nobel Prize in Medicine with Alexander Fleming for their role in making the scale-up production of antibiotic. The invention of penicillin from Pemcillium notation was convenient for the treatment of bacterial infections including syphilis, gangrene, and ТВ. Eventually, semi-synthetic penicillins and edible penicillins were produced. The systematic search began for other antibiotics and the new antibiotics were produced and commercialized.
1.6.3 INVENTION OF SULFONAMIDE DRUGS
German bacteriologist Gerhard Domagk found the second magic bullet against streptococcal infection after years of systematic research in 1932. This was a red dye called Prontosil. With the aid of the new, powerful electron microscopes which had been in use since the early 1930s, scientists found that the active component was a sulfonamide from coal tar. Soon after French workers found that the Prontosil could be metabolized in the patient to sulfanilamide, which was the active antibacterial molecule. After 1935, this idea was to change when it was found that Prontosil could use against streptococcal infection. In 1936, British physician Leonard Colebrook and co-workers confirmed the effectiveness of both Prontosil and sulfanilamide in streptococcal septicemia . The major befits of sulfonamide drugs was the rapid action, superior potency, broad antibacterial range, with lesser toxicity. The discoveiy of sulfonamides led to the development of drugs which cured gonorrhea, pneumonia, meningitis, and scarlet fever. In subsequent years many derivatives of sulfonamides, or sulfa drugs, were synthesized and tested for antibacterial and other activities. Most of the antibiotic classes [Penicillins, Macro lides, Fluoroquinolones, Tetracyclines, Aminoglycosides, Sulfonamides, Cephalosporins, Glycopeptides, Carbapenems, Lincosamide, etc.], were discovered and introduced to the market between 1940 and 1962. There are generally several antibiotics in each class that have been found over time or are improved versions of earlier types.