Plague (disease)

Plague is an infectious disease caused by the bacterium Yersinia pestis. Symptoms include fever and headache; this begins one to seven days after exposure. In the bubonic form there is swelling of lymph nodes, while in the septicemic form tissues may turn black and die, in the pneumonic form shortness of breath and chest pain may occur. Bubonic and septicemic plague are spread by flea bites or handling an infected animal; the pneumonitic form is spread between people through the air via infectious droplets. Diagnosis is by finding the bacterium in fluid from a lymph node, blood or sputum; those at high risk may be vaccinated. Those exposed to a case of pneumonic plague may be treated with preventive medication. If infected, treatment is with supportive care. Antibiotics include a combination of gentamicin and a fluoroquinolone; the risk of death with treatment is about 10% while without it is about 70%. Globally about 600 cases are reported a year. In 2017 the countries with the most cases include the Democratic Republic of the Congo and Peru.

In the United States infections occur in rural areas, where the bacteria are believed to circulate among rodents. It has occurred in large outbreaks, with the best known being the Black Death in the 14th century, which resulted in more than 50 million deaths; when a flea bites a human and contaminates the wound with regurgitated blood, the plague-carrying bacteria are passed into the tissue. Y. pestis can reproduce inside cells, so if phagocytosed, they can still survive. Once in the body, the bacteria can enter the lymphatic system. Plague bacteria secrete several toxins, one of, known to cause beta-adrenergic blockade. Y. Pestis spreads through the lymphatic vessels of the infected human until it reaches a lymph node, where it causes acute lymphadenitis; the swollen lymph nodes form the characteristic buboes associated with the disease, autopsies of these buboes have revealed them to be hemorrhagic or necrotic. If the lymph node is overwhelmed, the infection can pass into the bloodstream, causing secondary septicemic plague and if the lungs are seeded, it can cause secondary pneumonic plague.

Lymphatics drain into the bloodstream, so the plague bacteria may enter the blood and travel to any part of the body. In septicemic plague, bacterial endotoxins cause disseminated intravascular coagulation, causing tiny clots throughout the body and ischemic necrosis from the clots. DIC results in depletion of the body's clotting resources, so that it can no longer control bleeding. There is bleeding into the skin and other organs, which can cause red and/or black patchy rash and hemoptysis/hematemesis. There are bumps on the skin. Untreated, septicemic plague is fatal. Early treatment with antibiotics reduces the mortality rate to between 15 percent. People who die from this form of plague die on the same day symptoms first appear; the pneumonic form of plague arises from infection of the lungs. It causes coughing and sneezing and thereby produces airborne droplets that contain bacterial cells and are to infect anyone inhaling them; the incubation period for pneumonic plague is short two to four days, but sometimes just a few hours.

The initial signs are indistinguishable from several other respiratory illnesses. The course of the disease is rapid. Transmission of Y. pestis to an uninfected individual is possible by any of the following means. Droplet contact – coughing or sneezing on another person direct physical contact – touching an infected person, including sexual contact indirect contact – by touching soil contamination or a contaminated surface airborne transmission – if the microorganism can remain in the air for long periods fecal-oral transmission – from contaminated food or water sources vector borne transmission – carried by insects or other animals. Yersinia pestis circulates in animal reservoirs in rodents, in the natural foci of infection found on all continents except Australia; the natural foci of plague are situated in a broad belt in the tropical and sub-tropical latitudes and the warmer parts of the temperate latitudes around the globe, between the parallels 55 degrees North and 40 degrees South. Contrary to popular belief, rats did not directly start the spread of the bubonic plague.

It is a disease in the fleas that infested the rats, making the rats themselves the first victims of the plague. Infection in a human occurs when a person is bitten by a flea, infected by biting a rodent that itself has been infected by the bite of a flea carrying the disease; the bacteria multiply inside the flea, sticking together to form a plug that blocks its stomach and causes it to starve. The flea bites a host and continues to feed though it cannot quell its hunger, the flea vomits blood tainted with the bacteria back into the bite wound; the bubonic plague bacterium infects a new person and the flea dies from starvation. Serious outbreaks of plague are started by other disease outbreaks in rodents, or a rise in the rodent population. Since human plague is rare in most parts of the world, routine vaccination is not needed other than for those at high

San Giovanni in Marignano

San Giovanni in Marignano is a comune in the Province of Rimini in the Italian region Emilia-Romagna, located about 130 kilometres southeast of Bologna and about 20 kilometres southeast of Rimini. San Giovanni in Marignano borders the following municipalities: Cattolica, Misano Adriatico, Morciano di Romagna, San Clemente, Tavullia. Cattolica Airfield is an abandoned World War II US Air Force airfield in its vicinity. San Giovanni in Marignanon on The campanile Project

Polycera quadrilineata

Polycera quadrilineata, is a sea slug, a species of dorid nudibranch. It is a marine gastropod mollusc in the family Polyceridae; the specific epithet quadrilineata means four-lined and refers to the four longitudinal black lines present on the original specimen. This species is sometimes called the fourline nudibranch; this nudibranch is described from Norway. In the NE Atlantic it is a common species in shallow water, it is distributed from Greenland to Norway and south along the European coasts into the Mediterranean Sea. It has been reported off the South African coast from the Atlantic coast of the Cape Peninsula to Algoa Bay; the South African animals differ in having six instead of four papillae projecting from the frontal margin of the head, plus details of the coloration. It is found from the intertidal zone to 160 m; the fourline nudibranch is a smooth-bodied variably coloured nudibranch. The ground colour is white or grey and there are black, yellow or orange stripes longitudinally along the notum, though these can be absent.

The head has four or six yellow projections. The gills and rhinophores are translucent white. In the South African animals the gills and rhinophores are black, may be spotted with yellow. Alongside the gills is a pair of yellow-tipped projections; the animal may reach 20mm in total length. It is distinguished from the crowned nudibranch in having raised yellow spots on the mid-dorsal region. Polycera quadrilineata feeds on the bryozoans Membranipora membranacea and Electra pilosa. Montagu G. 1804: Description of several marine animals found on the South coast of Devonshire. D', 1837: Mémoire sur des espèces et sur des genres nouveaux de l'ordre des nudibranches observés sur les côtes de France. Part 2. F. 8: 12-48 Dautzenberg P. & Durouchoux P. 1913-1914: Les mollusques de la baie de Saint-Malo: Feuille des Jeunes Naturalistes 43-44: 1-64, pl. 1-4 Labbé A. 1931: Les Polycerades de la station du Croisic et description sommaire d'une espèce nouvelle: Polycera salamandra n. sp.. Photos of Polycera quadrilineata on Sealife Collection