Infection, plague

Micro-organisms were discovered by Antonie van Leeuwenhoek in Delft (Holland) in 1676, but their role in causing infections, plagues, and epidemics was established only two centuries later, by Robert Koch through his work on anthrax. Koch, and his four postulates for ensuring that a suspected microbe actually caused a given disease made it possible for biologists to study infectious diseases experimentally for the first time. This set the scene for the discovery of chemotherapy, but it was slow to arrive as we shall see. 

Tetracyclines a group of antibiotics from various Streptomyces spp. T. contain four linearly fused six-membered rin individual T. differ according to the nature of substituents (Fig. and Table). T. inhibit protein biosynthesis by preventing the binding of ami-noacyl-tRNA to ribosomes. Next to the penicillins, T. were one of the most widely used antibiotics, particularly in the treatment of bronchitis, pneumonia, bile duct and urinary infections, plague and cholera. They are also widely employed as additives in animal feed-stuffs. On account of side reactions and increasing resistance of bacteria to T. their use is declining. 

Suggested Alternatives for Differential Diagnosis Psittacosis, Q fever, plague, diphtheria, tick-borne diseases, mycotic infections. 

Suggested Alternatives for Differential Diagnosis Other causes of pneumonia, typhoid fever, tuberculosis, plague, anthrax infection, smallpox. 

Suggested Alternatives for Differential Diagnosis Acute respiratory distress syndrome, plague, congestive heart failure and pulmonary edema, HIV infection and AIDS, pneumonia, shock, phosgene, influenza, tularemia, phosphine toxicity, anthrax, silent myocardial infarction, and salicylate toxicity with pulmonary edema. 

PX (Japanese WWII Code for Plague Infected Fleas) C17-A030... 

Differential Diagnosis An epidemic of inhalation anthrax in its early stage with nonspecific symptoms could be confused with a number of viral, bacteria, and fungal infections. Progression over two to three days with sudden development of severe respiratory distress followed by shock and death within twenty-four to thirty-six hours in essentially all untreated cases eliminates diagnosis other than inhalation anthrax. Other diagnosis to consider would include aerosol exposure to staphylococcal enterotoxin B (SEB), plague, or tularemia pneumonia. 

Caution The death rate from untreated pneumonic plague can reach almost 100 percent. Once a human is infected with plague, a progressive and potentially deadly illness usually results unless antibody therapy is administered. In a progressional sequence, the patient develops blood infection which leads to lung infection. 

Bubonic plague is the most common form of plague. This occurs when an infected flea bites a person or when materials contaminated with Y. pestis enter through a break in a person s skin. Patients develop swollen, tender lymph glands (called buboes) and fever, headache, chills, and weakness. Bubonic plague does not spread from person to person. 

Pneumonic) Plague 1. Aerosol 2. Infected vectors High High 2-3 days 1-2 days Very high Less important because of high transmissibility Yes Moderately effective No... 

In addition to plaguing humans directly, flies spread pathogens that infect a significant number of plants and animals. Veterinary medicine must deal with horse flies and black flies, as well as pests with such curious names as warble flies and bot flies. There are ubiquitous stable flies that look like everyday house flies but deliver a painful bite, and a multitude of less familiar species that prey on sheep, rodents, and rabbits. Flies that are crop pests typically feed on their plant hosts as larvae. Seedcorn maggots, for... 

The European bubonic plague of 1347 killed one-third of the population of Europe. It is the largest single plague ever recorded. The disappearance of the Aztec civilization was spurred by smallpox and measles introduced by Hernando Cortes and his band of Spanish invaders. The same diseases also decimated Native Americans in what is now the United States. Much more recently, the influenza epidemic of 1918 killed an estimated 40 million people worldwide. Malaria continues to be a major problem for people and their countries today in areas in which it is endemic. AIDS, tuberculosis, influenza, hepatitis, pneumonia, and a lengthy list of parasitic infections continue as important constraints on the welfare of people throughout the world. 

Despite the remarkable natural defence mechaifisms that have evolved, they have not always been successful and infections have, on occasions, produced catastrophic effects on the human population (Box 17.6). Two examples are the plague pandemic of the mid-1300s (Box 17.7), and the influenza pandemic of the early 1900s. This is due, in part, to the ability of the pathogen to avoid detection or killing by the immune system. 

Tapeworm infections are caused by Taenia solium. Tinea pedis causes the fungal infection known os athlete s foot. Yersinia pestis is implicated in plague, Candida albicans is responsible for candidiasis while Chlamydia frachomifis causes eye infections. 

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