in the 20th century, over 300–500 million. wolfgang amadeus mozart also had smallpox when he was only 11 years old. he survived the smallpox outbreak in austria. typhus main article: typhus § 19th century epidemic typhus is caused by the bacteria rickettsia prowazekii; it comes from lice. murine typhus is caused by the rickettsia typhi bacteria, from the fleas on rats. scrub typhus is caused by the orientia tsutsugamushi bacteria, from the harvest mites on humans and rodents. queensland tick typhus is caused by the rickettsia australis bacteria, from ticks. during napoleon's retreat from moscow in 1812, more french soldiers died of typhus than were killed by the russians. a major epidemic occurred in ireland between 1816 and 1819, during the year without a summer; an estimated 100,000 irish perished. typhus appeared again in the late 1830s, and between 1846 and 1849 during the great irish famine. spreading to england, and called "irish fever", it was noted for its virulence. it killed people of all social classes, as lice were endemic and inescapable, but it hit particularly hard in the lower or "unwashed" social strata. in canada alone, the typhus epidemic of 1847 killed more than 20,000 people from 1847 to 1848, mainly irish immigrants in fever sheds and other forms of quarantine, who had contracted the disease aboard coffin ships. in the united states, epidemics occurred in baltimore, memphis and washington dc between 1865 and 1873, and during the us civil war. yellow fever yellow fever virus this disease is transmitted by the bite of female mosquito; the higher prevalence of transmission by aedes aegypti has led to it being known as the yellow fever mosquito. the transmission of yellow fever is entirely a matter of available habitat for vector mosquito and prevention such as mosquito netting. they mostly infect other primates, but humans can be infected. the symptoms of the fever are: headaches, back and muscle pain, chills and vomiting, bleeding in the eyes and mouth, and vomit containing blood. yellow fever accounted for the largest number of the 19th-century's individual epidemic outbreaks, and most of the recorded serious outbreaks of yellow fever occurred in the 19th century. it is most prevalent in tropical-like climates, but the united states was not exempted from the fever. new orleans was plagued with major epidemics during the 19th century, most notably in 1833 and 1853. at least 25 major outbreaks took place in the americas during the 18th and 19th centuries, including particularly serious ones in santo domingo in 1803 and memphis in 1878. major outbreaks occurred repeatedly in gibraltar; outbreaks in 1804, 1814, and again in 1828. barcelona suffered the loss of several thousand citizens during an outbreak in 1821. urban epidemics continued in the united states until 1905, with the last outbreak affecting new orleans. plague the third plague pandemic was a major bubonic plague pandemic that began in yunnan, china in 1855. this episode of bubonic plague spread to all inhabited continents in the 1890s and first years of the 1900s, and ultimately led to more than 12,000,000 deaths in india and china, with about 10,000,000 killed in india alone. a natural reservoir of plague is located in western yunnan and is an ongoing health risk today. the third pandemic of plague originated in this area after a rapid influx of han chinese to exploit the demand for minerals, primarily copper, in the latter half of the 19th century. by 1850, the population had exploded to over 7,000,000 people. increasing transportation throughout the region brought people in contact with plague-infected fleas, the primary vector between the yellow-breasted rat (rattus flavipectus) and humans. the spread of european empires and the development of new forms of transport such as the steam engine made it easier for both humans and rats to spread the disease along existing trade routes. scarlet fever haemolytic streptococcus, which was identified in the 1880s, causes scarlet fever, which is a bacterial disease. scarlet fever spreads through respiratory droplets and children between the ages of 5 to 15 years were most affected by scarlet fever. scarlet fever had several epidemic phases, and around 1825 to 1885 outbreaks began to recur cyclically and often highly fatal. in the mid-19th century, the mortality caused by scarlet fever rose in england and wales. the major outbreak in england and wales took place during 1825–1885 with high mortality marking this as remarkable. there were several other notable outbreaks across europe, south america, and the united states in the 19th century. united kingdom in the uk, scarlet fever was considered benign for two centuries, but fatal epidemics were seen in the 1700s. scarlet fever broke out in england in the 19th century and was responsible for an enormous number of deaths in the 60-year period from 1825 to 1885; decades that followed had lower levels of annual mortality from scarlet fever. in nw england there was heavy mortality in liverpool. babies born in liverpool with a birthday in 1861 were only expected to live 26 years, and in larger cities, life expectancy was less than 35 years. over time, the life expectancy changed as well as the number of fatalities from scarlet fever. there was a reduction in child mortality from scarlet fever when you compare the decades, 1851–60 and 1891–1900. the decline of mortality seen for scarlet fever was noticed after the identification of streptococcus, but the decline was not associated with a treatment. a treatment would not be available until the introduction of sulphonamides in the 1930s, and the decline in mortality was due to the quality of air, food, and water improving. outbreaks of scarlet fever also took place in dublin in 1896 with 1,354 cases and 149 deaths, norway from 1862 to 1884, scotland in 1861, and in the rest of united kingdom. the united kingdom saw cases in canterbury from 1839 to 1865 with 305 deaths, bristol in 1870 with 106 deaths and in 1875, and manchester in 1886 with six cases. south america chile reported scarlet fever the first time in 1827 and highest rates were seen during winter months. the disease spread from valparaiso to santiago from 1831 to 1832 and claimed 7,000 lives. there were multiple outbreaks in different locations of chile, including copaipo in 1875 and caldera in 1876. united states similarly to europe, america considered scarlet fever to be benign for two centuries. in the early 19th century the scarlet fever impact drastically changed and lethal epidemics started to arise in the united states. the united states had a notable outbreak of scarlet fever in minnesota in 1847 and augusta, georgia had a lethal epidemic in 1832–1833. scarlet fever had low mortality rates in new york for many years before 1828, but remained high for long after. cases of scarlet fever were also seen in boston during a period of decreasing severity after 1885. boston city hospital opened a scarlet fever pavilion in 1887 to house patients with infectious diseases and saw nearly 25,000 patients during 1895–1905. in the mid-1800s, more specific epidemiological information was emerging and incidence in infants were found to be low. in 1870, the us census showed a decrease in scarlet fever mortality in children below the age of one.