Russia (see Cholera Riots), Hungary (about 100,000 deaths) and Germany in 1831, London in 1832 (more than 55,000 persons died in the United Kingdom), France, Canada (Ontario), and United States (New York City) in the same year, and the Pacific coast of North America by 1834. It is believed that more than 150,000 Americans died of cholera between 1832 and 1849. 1846–1860 cholera pandemic. Deeply affected Russia, with more than a million deaths. A two-year outbreak began in England and Wales in 1848 and claimed 52,000 lives. Throughout Spain, cholera caused more than 236,000 deaths in 1854–55. It claimed 200,000 lives in Mexico. 1863–1875 cholera pandemic. Spread mostly in Europe and Africa. At least 30,000 of the 90,000 Mecca pilgrims were affected by the disease. Cholera killed 90,000 people in Russia in 1866. In 1866, there was an outbreak in North America. It killed some 50,000 Americans. 1881–1896 cholera pandemic. The 1883–1887 epidemic cost 250,000 lives in Europe and at least 50,000 in the Americas. Cholera claimed 267,890 lives in Russia (1892); 120,000 in Spain; 90,000 in Japan and 60,000 in Persia. In 1892, cholera contaminated the water supply of Hamburg and caused 8,606 deaths. 1899–1923 cholera pandemic. Had little effect in Europe because of advances in public health, but Russia was badly affected again (more than 500,000 people dying of cholera during the first quarter of the 20th century). The sixth pandemic killed more than 800,000 in India. The 1902–1904 cholera epidemic claimed more than 200,000 lives in the Philippines. Seventh cholera pandemic (1961–present). Began in Indonesia, called El Tor after the new biotype responsible for the pandemic, and reached Bangladesh in 1963, India in 1964, and the Soviet Union in 1966. The pandemic thereafter reached Africa in 1971 and the Americas in 1991. As of March 2022, the World Health Organization continues to define this outbreak as a current pandemic, noting that cholera has become endemic in many countries. In 2017, WHO announced a global strategy aimed at this pandemic with the goal of reducing cholera deaths by 90% by 2030. Dengue fever Dengue is spread by several species of female mosquitoes of the Aedes type, principally A. aegypti. The virus has five types; infection with one type usually gives lifelong immunity to that type, but only short-term immunity to the others. Subsequent infection with a different type increases the risk of severe complications. Several tests are available