healers and governments were at a loss to explain or stop the disease, europeans turned to astrological forces, earthquakes and the poisoning of wells by jews as possible reasons for outbreaks. many believed the epidemic was a punishment by god for their sins, and could be relieved by winning god's forgiveness. there were many attacks against jewish communities. in the strasbourg massacre of february 1349, about 2,000 jews were murdered. in august 1349, the jewish communities in mainz and cologne were annihilated. by 1351, 60 major and 150 smaller jewish communities had been destroyed. during this period many jews relocated to poland, where they received a warm welcome from king casimir the great. social pieter bruegel's the triumph of death reflects the social upheaval and terror that followed plague, which devastated medieval europe. one theory that has been advanced is that the devastation in florence caused by the black death, which hit europe between 1348 and 1350, resulted in a shift in the world view of people in 14th-century italy and led to the renaissance. italy was particularly badly hit by the pandemic, and it has been speculated that the resulting familiarity with death caused thinkers to dwell more on their lives on earth, rather than on spirituality and the afterlife. it has also been argued that the black death prompted a new wave of piety, manifested in the sponsorship of religious works of art. this does not fully explain why the renaissance occurred in italy in the 14th century. the black death was a pandemic that affected all of europe in the ways described, not only italy. the renaissance's emergence in italy was most likely the result of the complex interaction of the above factors, in combination with an influx of greek scholars following the fall of the byzantine empire. as a result of the drastic reduction in the populace the value of the working class increased, and commoners came to enjoy more freedom. to answer the increased need for labour, workers travelled in search of the most favorable position economically. prior to the emergence of the black death, the workings of europe were run by the catholic church and the continent was considered a feudalistic society, composed of fiefs and city-states. the pandemic completely restructured both religion and political forces; survivors began to turn to other forms of spirituality and the power dynamics of the fiefs and city-states crumbled. cairo's population, partly owing to the numerous plague epidemics, was in the early 18th century half of what it was in 1347. the populations of some italian cities, notably florence, did not regain their pre-14th century size until the 19th century. the demographic decline due to the pandemic had economic consequences: the prices of food dropped and land values declined by 30–40% in most parts of europe between 1350 and 1400. landholders faced a great loss, but for ordinary men and women it was a windfall. the survivors of the pandemic found not only that the prices of food were lower but also that lands were more abundant, and many of them inherited property from their dead relatives, and this probably destabilised feudalism. the word "quarantine" has its roots in this period, though the concept of isolating people to prevent the spread of disease is older. in the city-state of ragusa (modern dubrovnik, croatia), a thirty-day isolation period was implemented in 1377 for new arrivals to the city from plague-affected areas. the isolation period was later extended to forty days, and given the name "quarantino" from the italian word for "forty". recurrences second plague pandemic the great plague of london, in 1665, killed up to 100,000 people. a plague doctor and his typical apparel during the 17th-century outbreak. the plague repeatedly returned to haunt europe and the mediterranean throughout the 14th to 17th centuries. according to jean-noël biraben, the plague was present somewhere in europe in every year between 1346 and 1671. (note that some researchers have cautions about the uncritical use of biraben's data.) the second pandemic was particularly widespread in the following years: 1360–63; 1374; 1400; 1438–39; 1456–57; 1464–66; 1481–85; 1500–03; 1518–31; 1544–48; 1563–66; 1573–88; 1596–99; 1602–11; 1623–40; 1644–54; and 1664–67. subsequent outbreaks, though severe, marked the retreat from most of europe (18th century) and northern africa (19th century). the historian george sussman argued that the plague had not occurred in east africa until the 1900s. however, other sources suggest that the second pandemic did indeed reach sub-saharan africa. according to historian geoffrey parker, "france alone lost almost a million people to the plague in the epidemic of 1628–31." in the first half of the 17th century, a plague killed some 1.7 million people in italy. more than 1.25 million deaths resulted from the extreme incidence of plague in 17th-century spain. the black death ravaged much of the islamic world. plague could be found in the islamic world almost every year between 1500 and 1850. sometimes the outbreaks affected small areas, while other outbreaks affected multiple regions. plague repeatedly struck the cities of north africa. algiers lost 30,000–50,000 inhabitants to it in 1620–21, and again in 1654–57, 1665, 1691 and 1740–42. cairo suffered more than fifty plague epidemics within 150 years from the plague's first appearance, with the final outbreak of the second pandemic there in the 1840s. plague remained a major event in ottoman society until the second quarter of the 19th century. between 1701 and 1750, thirty-seven larger and smaller epidemics were recorded in constantinople, and an additional thirty-one between 1751 and 1800. baghdad has suffered severely from visitations of the plague, and sometimes two-thirds of its population had died. third plague pandemic worldwide distribution of plague-infected animals, 1998 the third plague pandemic (1855–1859) started in china in the mid-19th century, spreading to all inhabited continents and killing 10 million people in india alone. the investigation of the pathogen that caused the 19th-century plague was begun by teams of scientists who visited hong kong in 1894, among whom was the french-swiss bacteriologist alexandre yersin, after whom the pathogen was named. twelve plague outbreaks in australia between 1900 and 1925 resulted in well over 1,000 deaths, chiefly in sydney. this led to the establishment of a public health department there which undertook some leading-edge research on plague transmission from rat fleas to humans via the bacillus yersinia pestis. the first north american plague epidemic was the san francisco plague of 1900–1904, followed by another outbreak in 1907–1908. modern-day modern treatment methods include insecticides, the use of antibiotics, and a plague vaccine. it is feared that the plague bacterium could develop drug resistance and again become a major health threat. one case of a drug-resistant form of the bacterium was found in madagascar in 1995. a further outbreak in madagascar was reported in november 2014. in october 2017, the deadliest outbreak of the plague in modern times hit madagascar, killing 170 people and infecting thousands. an estimate of the case fatality rate for the modern bubonic plague, following the introduction of antibiotics, is 11%, although it may be higher in underdeveloped regions.