Yersinia Pestis free essay sample

Yersinia pestis is a gram negative, rod-shaped, facultative anaerobic bacterium, known for causing the plague. The reason why Y. pestis is so successful is because of their elusiveness to the hosts immune system and their ability to suppress it. Traces of the plague go as far back as to ancient times and specifically 5th century BC Athens and Sparta. Pathophysiology mi. pestis produces two anti-phagocytic antigens, Fl antigen and antigen. These antigens are both required for virulence and are only produced when the rganism grows at 37 degrees C temperatures, which explains why fleas, whose body temperatures are lower than that, can act as a vector. Y. pestis can also resist phagocytosis by injecting macrophages and immune cells with YOPS (Yersinia Outer Proteins). The YOPS are able to create pours in the cell, allowing more YOPS to get into the cytoplasm and limit phagocytosis. (Dramcourt, M. , 2013) miersinia Pestis is primarily a rodent pathogen, with humans being an accidental host when bitten by an infected rat flea. We will write a custom essay sample on Yersinia Pestis or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page (Schoenstadt, A. , 2013) miersinia pestis infections occur more frequently during spring and summer onths, especially in males and people under the age of 20. There are two cycles to the plague: Sylvatic Cycle and Urban Cycle. The Sylvatic Cycle is pre-human infection. Y. pestis, during this cycle, starts out in wild rodents which are then bit by fleas. The fleas will transfer the plague between the wild rodents until that population is dead. This cycle continues on in this fashion until either all the rodents are dead, or the fleas find a new food source, usually domestic rats. Once a domestic rat gets bitten, or another domestic animal, the Urban Cycle starts. The tart of this cycle is similar to the Sylvatic cycle, where the fleas will bite one domestic animal and then spread it to the next. During this cycle is when humans get infected. (Dramcourt, M. , 2013) If a flea that carries Y. pestis happens to bite a human then that human is infected. While in the human, there are two different ways the plague can manitest itselt: the Bubonic Plague or Pneumonic Plague. (Schoenstadt, A. 2013) Manifestation The Bubonic Plague after about 2 to 7 days will cause a painful bubo, a swelling of the lymph nodes usually in the groin. A fever and gangrene in the extremities typically accompany the bubo. The appearance of gangrene is what gave the plague the nickname The Black Death. While in the nodes, Y. pestis avoids the immune system, and replicates, causing the lymph nodes to swell. The nodes will get hot, tender, and then they will start to bleed excessively. As the plague develops, the bacteria move into the blood stream. Without treatment, death by endotoxic shock will occur in about 50 to 75% of all patients. If the bacteria move into the lungs, Pneumonic Plague develops. (Houhamdi L , 2013) Unlike Bubonic Plague, Pneumonic Plague; however, does not require a vector, but can instead be transmitted from human to human. Pneumonic Plague has an incubation time of about 2 to 3 days, and starts with a fever, a general feeling of not being well, and tightness of the chest. If left untreated, the patient will develop a cough, produce high levels of sputum, their skin will turn blue, and then 99% of patients will die. (Schoenstadt, A. 2013) Medical Management The common treatment of the plague is Streptomycin which lowers the mortality ate to 10 to 20%, the first treatment needs to be initiated within 24 hours of the first signs of symptoms. The most common oral medications used for curing and preventing the disease are tetracycline, doxycycline, and a fluoroquinolone. For injection or intravenous use, str eptomycin or gentamycin antibodies are Raoult D. , 2013)