<P> Also known as the modern pandemic, the third pandemic spread the disease to port cities throughout the world in the second half of the 19th century and early 20th century via shipping routes . The plague inflicted people in Chinatown in San Francisco from 1900 - 1904, and the people of Oakland and east bay again from 1907 - 1909 . During the outbreak from 1900 - 1904 in San Francisco is when authorities made permanent the Chinese Exclusion Act . This law was originally signed into existence by President Chester A. Arthur in 1882 . The Chinese Exclusion Act was supposed to last for ten years but was renewed in 1892 with the Geary Act and subsequently made permanent in 1902 during the outbreak of plague in Chinatown, San Francisco . The last major outbreak in the United States occurred in Los Angeles in 1924, though the disease is still present in wild rodents, and can be passed to humans that come in contact with them . According to the World Health Organization, the pandemic was considered active until 1959, when worldwide casualties dropped to 200 per year . In 1994, a plague outbreak in five Indian states caused an estimated 700 infections (including 52 deaths) and triggered a large migration of Indians within India as they tried to avoid the plague . </P> <P> For over a decade since 2001, Zambia, India, Malawi, Algeria, China, Peru, and the Democratic Republic of the Congo had the most plague cases with over 1,100 cases in the Democratic Republic of the Congo alone . From 1,000 to 2,000 cases are conservatively reported per year to the WHO . From 2012 and to 2017 and reflecting political unrest and poor hygienic conditions, Madagascar began to host regular epidemics . </P> <P> Between 1900 and 2015, the United States had 1,036 human plague cases with an average of 9 cases per year . In 2015, 16 people in the Western United States developed plague, including 2 cases in Yosemite National Park . These US cases usually occur in rural northern New Mexico, northern Arizona, southern Colorado, California, southern Oregon, and far western Nevada . </P> <P> In November 2017, the Madagascar Ministry of Health reported an outbreak to WHO (World Health Organization) with more cases and deaths than any recent outbreak in the country . Unusually most of the cases were pneumonic rather than bubonic . </P>

Who discovered the first effective treatment of the black death