Smallpox was declared eradicated in 1980 by the [[WHO]]. The true [[incidence]] of [[smallpox]] before its eradication is difficult to estimate due to poor reporting from endemic regions, which may have reported only 1-2% of the cases. Children and young adults were the most often affected, especially in regions with low levels of [[immunity]]. There is no evidence of gender or race differences in the [[incidence]] of the disease. Developing countries had a higher [[incidence]] of the disease.<ref name=WHO>{{cite web|title=The epidemiology of smallpox|url = http://whqlibdoc.who.int/smallpox/9241561106_chp4.pdf}}</ref>
==Eurasia==
==Incidence==
It is important to note that, while historical [[epidemic]]s and [[pandemic]]s are believed by some historians to have been early outbreaks of smallpox, contemporary records are not detailed enough to make a definite diagnosis at this distance.<ref name=Hopkins_2002>{{cite book | author = Hopkins DR | title = The Greatest Killer: Smallpox in history | edition = | publisher = University of Chicago Press | year = 2002 | isbn = 0-226-35168-8 }} Originally published as ''Princes and Peasants: Smallpox in History'' (1983), ISBN 0-226-35177-7</ref>
The number of new cases, reported to the international health authorities, was often inaccurate. The data obtained from non-endemic countries, with good health services, was probably the most accurate. Yet, according to the ''Intensified Smallpox Eradication Programme'', the reported [[incidence]] amounted only to 1-2% of the actual number of cases, which made it impossible to obtain an accurate estimate of the [[incidence]].<ref name=WHO>{{cite web|title=The epidemiology of smallpox|url = http://whqlibdoc.who.int/smallpox/9241561106_chp4.pdf}}</ref>
The [[Plague of Athens]] devastated the city of Athens in 430 BC, killing around a third of the population, according to Thucydides. Historians have long considered this an example of [[bubonic plague]], but more recent examination of the reported symptoms led some scholars to believe the cause may have been [[measles]], smallpox, [[typhus]], or a [[viral hemorrhagic fever]] (like [[Ebola virus|Ebola]]).
[[Image:Smallpox-1.png|left|400px|thumb|Incidence of reported cases in the 31 countries and territories in which smallpox was endemic in 1967.<SMALL><SMALL>''[http://whqlibdoc.who.int/smallpox/9241561106_chp4.pdf Adapted from World Health Organization (WHO)]''<ref name="WHO">{{Cite web | title = World Health Organization (WHO) | url = http://whqlibdoc.who.int/smallpox/9241561106_chp4.pdf}}</ref></SMALL></SMALL>]]<br clear="left"/>
The [[Antonine Plague]] that swept through the Roman Empire and Italy in 165–180 is also thought to be either smallpox or measles.<ref>[http://www.annals.org/cgi/content/full/127/8_Part_1/635 Annals of Internal Medicine]</ref> <ref name=Hopkins_2002 /> A second major outbreak of disease in the Empire, known as the [[Plague of Cyprian]] (251–266), was also either smallpox or measles.
In [[endemic]] regions there were periods called ''epidemic years'' in which the [[incidence]] was much higher. In order to try to justify this discrepancy, several possibilities were evoked, such as:<ref name=WHO>{{cite web|title=The epidemiology of smallpox|url = http://whqlibdoc.who.int/smallpox/9241561106_chp4.pdf}}</ref>
* Viability of the [[virus]]
* Changes in susceptibility of the host
* Social factors, such as dispersion of the population
* Seasonal variation in [[incidence]] in relation to eradication
The next major epidemic believed to be smallpox occurred in India]. The exact date is unknown. Around A.D. 400, an Indian medical book recorded a disease marked by pustules, saying "the pustules are red, yellow, and white and they are accompanied by burning pain … the skin seems studded with grains of rice." The Indian epidemic was thought to be punishment from a god, and the survivors created a goddess, Sitala, as the anthropomorphic personification of the disease.<ref name=Nicholas_1981>{{cite journal | author = Nicholas R | title = The goddess Sitala and epidemic smallpox in Bengal. | journal = J Asian Stud | volume = 41 | issue = 1 | pages = 21-45 | year = 1981 | pmid = 11614704}}</ref><ref name=Sitala>{{cite web | title=Sitala and Smallpox | work=The thermal qualities of substance: Hot and Cold in South Asia |url = http://www.icsi.berkeley.edu/~snarayan/anthro-pap/subsection3_4_3.html | accessdate = 2006-09-23}}</ref><ref>http://reli350.vassar.edu/kissane/sitala.html Vassar: Points out that variolation was regarded as a means of invoking the goddess whereas vaccination was opposition to her. Gives duration of belief as until 50 years ago.</ref> Smallpox was thus regarded as possession by Sitala. In Hinduism the goddess Sitala both causes and cures high fever, rashes, hot flashes and pustules. All of these are symptoms of smallpox.
==Age==
The age adjusted [[incidence]] of the disease may vary depending upon the level of acquired [[immunity]] in the population. When populations were exposed to the disease for the first time, all ages would be affected. In [[endemic]] regions, where there was some previous level of [[immunity]], children and young adults were the most severely affected.<ref name=PubMed>{{cite web|title=Smallpox|url = http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0002332/}}</ref><ref name=WHO>{{cite web|title=The epidemiology of smallpox|url = http://whqlibdoc.who.int/smallpox/9241561106_chp4.pdf}}</ref><ref name=CDC>{{cite web | title = Emergency Preparedness and Response | url = http://www.bt.cdc.gov/agent/smallpox/ }}</ref>
Smallpox did not definitively enter Western Europe until about 581 when Bishop Gregory of Tours provided an eyewitness account that describes the characteristic findings of smallpox.<ref name=Hopkins_2002 /> Most of the details about the epidemic that followed are lost, probably due to the scarcity of surviving written records of early medieval society.
==Gender==
[[Smallpox]] affected males and females equally.<ref name=WHO>{{cite web|title=The epidemiology of smallpox|url = http://whqlibdoc.who.int/smallpox/9241561106_chp4.pdf}}</ref><ref name=CDC>{{cite web | title = Emergency Preparedness and Response | url = http://www.bt.cdc.gov/agent/smallpox/ }}</ref>
==The Americas==
==Race==
The incidence of smallpox did not differ according to the race.<ref name=WHO>{{cite web|title=The epidemiology of smallpox|url = http://whqlibdoc.who.int/smallpox/9241561106_chp4.pdf}}</ref><ref name=CDC>{{cite web | title = Emergency Preparedness and Response | url = http://www.bt.cdc.gov/agent/smallpox/ }}</ref>
{| class = "prettytable" style = "float:right; font-size:85%; margin-left:15px; width:50%"
==Developed Countries==
|-
Developed countries, due to a better and established health system, had lower [[incidence]] of [[smallpox]] and better reports of new cases to international organizations.<ref name=WHO>{{cite web|title=The epidemiology of smallpox|url = http://whqlibdoc.who.int/smallpox/9241561106_chp4.pdf}}</ref>
! colspan=3 rowspan=1| Documented Smallpox Epidemics in the New World<ref name="smallpxchart"> [http://www.genealogyinc.com/enc_epidemics/index.html] Worldwide Epidemics 1999 Genealogy Inc </ref>
|-
!rowspan=1|<small>Year</small>
!rowspan=1|<small>Location</small>
!rowspan=1|<small>Description</small>
|-
| align=left | 1520-1527 || align=left | Mexico, Central America, South America || align=left | Smallpox kills millions of native inhabitants of Mexico. Unintentionally introduced at Veracruz with the arrival of Panfilo de Narvaez on April 23, 1520<ref>[http://www.randomhouse.com/features/richardpreston/timeline.html The Demon in the Freezer]</ref> and was credited with the victory of Cortes over the Aztec empire at Tenochtitlan (present-day Mexico City) in 1521. Kills the Inca ruler, Huayna Capac, and 200,000 others and destroys the Incan Empire.
|-
| align=left | 1617-1619 || align=left | North America northern east coast || align=left | Killed 90% of the Massachusetts Bay Indians
|-
| align=left | 1674 || align=left | Cherokee Tribe || align=left | Death count unknown. Population in 1674 about 50,000. After 1729, 1738, and 1753 smallpox epidemics their population was only 25,000 when they were forced to Oklahoma on the Trail Of Tears
| align=left | 1754-1767 || align=left | North East U.S. and South East Canada || align=left |"Smallpox was probably first used as a biological weapon during the French and Indian Wars of 1754-1767 when British forces in North America distributed blankets that had been used by smallpox patients among them to Native Americans collaborating with the French."<ref name=Consensus_1999 />
|-
| align=left | 1770s || align=left | West Coast of North America || align=left | Kills out 30% of the West Coast Native Americans
| align=left | 1830s || align=left | Alaska || align=left | Reduced Dena'ina Athabaskan population in Cook Inlet region of southcentral Alaska by half.<ref>{{cite book | author = Boraas AS | authorlink = Alan Boraas | title = Peter Kalifornsky: A Biography. In: A Dena’ina Legacy — K’tl’egh’i Sukdu: The Collected Writings of Peter Kalifornsky (Kari J, Boraas AS, eds)| pages = 475 | publisher = Alaska Native Language Center, University of Alaska Fairbanks |location = Fairbanks, AK | year = 1991 | isbn = }}</ref> Smallpox also devastated Yup'ik Eskimo populations in western Alaska.<!-- locating cite -->
| align=left | 1865-1873 || align=left | Philadelphia, PA, New York, Boston, MA and New Orleans, LA || align=left | Same period of time, in Washington DC, Baltimore, MD, Memphis, TN Cholera and a series of recurring epidemics of Typhus, Scarlet Fever and Yellow Fever
|-
| align=left | 1877 || align=left | Los Angeles, CA || align=left |
|-
|}
After first contacts with Europeans and Africans, some believe that the death of 90 to 95 percent of the native population of the New World was caused by Old World diseases.<ref>[http://www.pbs.org/gunsgermssteel/variables/smallpox.html The Story Of... Smallpox]</ref> It is suspected that smallpox was the chief culprit and responsible for killing nearly all of the native inhabitants of the Americas. For more than two hundred years, this disease affected all new world populations, mostly without intentional European transmission (Excluding the British Settlements), from contact in the early 1500s to until possibly as early as the French and Indian Wars (1754-1767).<ref name=Consensus_1999>{{cite journal |author=Henderson DA, Inglesby TV, Bartlett JG, ''et al'' |title=Smallpox as a biological weapon: medical and public health management. Working Group on Civilian Biodefense |journal=JAMA |volume=281 |issue=22 |pages=2127-37 |year=1999 |pmid=10367824 |url=http://jama.ama-assn.org/cgi/reprint/281/22/2127.pdf}}</ref>
==Developing Countries==
In developing countries where healthcare facilities are sometimes not trusted by the population, cases were sometimes not reported to public health authorities. Also, vaccination was not sanctioned by some religious beliefs. Taken together, these factors might explain at least in part the higher incidence of [[smallpox]] in developing countries.<ref name=WHO>{{cite web|title=The epidemiology of smallpox|url = http://whqlibdoc.who.int/smallpox/9241561106_chp4.pdf}}</ref>
In 1519 Hernán Cortés landed on the shores of what is now Mexico and was then the Aztec empire. In 1520 another group of Spanish came from Cuba and landed in Mexico. Among them was an African slave who had smallpox. When Cortés heard about the other group, he went and defeated them. In this contact, one of Cortés's men contracted the disease. When Cortés returned to Tenochtitlan, he brought the disease with him.
==References==
{{Reflist|2}}
Soon, the Aztecs rose up in rebellion against Cortés. Outnumbered, the Spanish were forced to flee. In the fighting, the Spanish soldier carrying smallpox died. After the battle, the Aztecs contracted the virus from the invaders' bodies. Cortes would not return to the capital until August 1521. In the meantime smallpox devastated the Aztec population. It killed most of the Aztec army, the emperor, and 25% of the overall population. A Spanish priest left this description: "As the Indians did not know the remedy of the disease…they died in heaps, like bedbugs. In many places it happened that everyone in a house died and, as it was impossible to bury the great number of dead, they pulled down the houses over them so that their homes become their tombs." On Cortés's return, he found the Aztec army’s chain of command in ruins. The soldiers who lived were still weak from the disease. Cortés then easily defeated the Aztecs and entered Tenochtitlán, where he found that smallpox had killed more Aztecs than had the cannons. The Spaniards said that they could not walk through the streets without stepping on the bodies of smallpox victims.
[[Category:Disease]]
<!-- Unsourced image removed: [[Image:Smallpoxlarcomuseum.jpg|thumb|left|Moche Ceramic Depicting Small Pox. 300 A.D. Larco Museum Collection Lima, Peru.]] -->
[[Category:Pediatrics]]
The effects of smallpox on Tahuantinsuyu (or the Inca empire) were even more devastating. Beginning in Colombia, smallpox spread rapidly before the Spanish invaders first arrived in the empire. The spread was probably aided by the efficient Inca road system. Within months, the disease had killed the Sapa Inca Huayna Capac, his successor, and most of the other leaders. Two of his surviving sons warred for power and, after a bloody and costly war, Atahualpa become the new Sapa Inca. As Atahualpa was returning to the capital Cuzco, Francisco Pizarro arrived and through a series of deceits captured the young leader and his best general. Within a few years smallpox claimed between 60% and 90% of the Inca population<ref>[http://muweb.millersville.edu/~columbus/papers/orlow-e.html Silent Killers of the New World]</ref>, with other waves of European disease weakening them further. However, some historians think a serious native disease called Bartonellosis may have been responsible for some outbreaks of illness. The effects of smallpox were dipicted in the ceramics of the Moche people of ancient Peru. <ref>Berrin, Katherine & Larco Museum. ''The Spirit of Ancient Peru:Treasures from the [[Larco Museum|Museo Arqueológico Rafael Larco Herrera]].'' New York: Thames and Hudson, 1997.</ref>
[[Category:Smallpox]]
[[Category:Viral diseases]]
Even after the two mighty empires of the Americas were defeated by the virus, smallpox continued its march of death. In 1633 in Plymouth, Massachusetts, the Native Americans were struck by the virus. As it had done elsewhere, the virus wiped out entire population groups of Native Americans. It reached Lake Ontario in 1636, and the lands of the Iroquois by 1679, killing millions. The worst sequence of smallpox attacks took place in Boston, Massachusetts. From 1636 to 1698, Boston endured six epidemics. In 1721, the most severe epidemic occurred. The entire population fled the city, bringing the virus to the rest of the Thirteen Colonies. [[North American smallpox epidemic|In the late 1770s]], during the American Revolutionary War, smallpox returned once more and killed an estimated 125,000 people.<ref name=Fenn_2001>{{cite book | author = Fenn EA | title = Pox Americana: The Great Smallpox Epidemic of 1775-82 | edition = 1st ed. | publisher = Hill and Wang | year = 2001 | isbn = 0-8090-7820-1 }}</ref> Peter Kalm in his ''“Travels in North America”'', described how in that period, the dying Indian villages became overrun with wolves feasting on the corpses and weakened survivors.<ref name="BO">{{cite web | url = http://www.rangemagazine.com/archives/stories/summer03/ground-hog.htm | title = Groundhog day at the wolf wars | work = | publisher = | accessdate = 2007-06-18}}</ref>
Smallpox was declared eradicated in 1980 by the WHO. The true incidence of smallpox before its eradication is difficult to estimate due to poor reporting from endemic regions, which may have reported only 1-2% of the cases. Children and young adults were the most often affected, especially in regions with low levels of immunity. There is no evidence of gender or race differences in the incidence of the disease. Developing countries had a higher incidence of the disease.[1]
Incidence
The number of new cases, reported to the international health authorities, was often inaccurate. The data obtained from non-endemic countries, with good health services, was probably the most accurate. Yet, according to the Intensified Smallpox Eradication Programme, the reported incidence amounted only to 1-2% of the actual number of cases, which made it impossible to obtain an accurate estimate of the incidence.[1]
In endemic regions there were periods called epidemic years in which the incidence was much higher. In order to try to justify this discrepancy, several possibilities were evoked, such as:[1]
Social factors, such as dispersion of the population
Seasonal variation in incidence in relation to eradication
Age
The age adjusted incidence of the disease may vary depending upon the level of acquired immunity in the population. When populations were exposed to the disease for the first time, all ages would be affected. In endemic regions, where there was some previous level of immunity, children and young adults were the most severely affected.[2][1][3]
The incidence of smallpox did not differ according to the race.[1][3]
Developed Countries
Developed countries, due to a better and established health system, had lower incidence of smallpox and better reports of new cases to international organizations.[1]
Developing Countries
In developing countries where healthcare facilities are sometimes not trusted by the population, cases were sometimes not reported to public health authorities. Also, vaccination was not sanctioned by some religious beliefs. Taken together, these factors might explain at least in part the higher incidence of smallpox in developing countries.[1]
