Smallpox epidemiology and demographics: Difference between revisions
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==Overview== | ==Overview== | ||
The true [[incidence]] of [[smallpox]], before declared eradicated in 1980 by the [[WHO]], wasn't possible to specify due to the great lack of reports of new cases from countries, particularly from the endemic regions, in which the reported numbers are stipulated to be 1-2% of the reality. Children and young adults were the most affected, especially in regions with low level of [[immunity]]. There is no evidence of gender or race difference in the [[incidence]] of the disease. Developing countries had a higher [[incidence]] of the disease. | The true [[incidence]] of [[smallpox]], before declared eradicated in 1980 by the [[WHO]], wasn't possible to specify due to the great lack of reports of new cases from countries, particularly from the endemic regions, in which the reported numbers are stipulated to be 1-2% of the reality. Children and young adults were the most affected, especially in regions with low level of [[immunity]]. There is no evidence of gender or race difference 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> | ||
==Incidence== | ==Incidence== | ||
The number of cases reported to the international health authorities varied greatly in accuracy. The data obtained from non-endemic countries, with good health services were probably more accurate. | The number of cases reported to the international health authorities varied greatly in accuracy. The data obtained from non-endemic countries, with good health services were probably more accurate. | ||
According to the ''Intensified Smallpox Eradication Programme'', the reported incidence amounted to 1-2% of the reality, therefore it is not possible to obtain a true number on the incidence. | According to the ''Intensified Smallpox Eradication Programme'', the reported incidence amounted to 1-2% of the reality, therefore it is not possible to obtain a true number on the incidence.<ref name=WHO>{{cite web|title=The epidemiology of smallpox|url = http://whqlibdoc.who.int/smallpox/9241561106_chp4.pdf}}</ref> | ||
[[Image:Smallpox-1.png|left|400px|thumb|Incidence of reported cases in the 31 countries and territories in which smallpox was endemic in 1967.]]<br clear="left"/> | [[Image:Smallpox-1.png|left|400px|thumb|Incidence of reported cases in the 31 countries and territories in which smallpox was endemic in 1967.]]<br clear="left"/> | ||
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==Age== | ==Age== | ||
The [[incidence]] of the disease | The age [[incidence]] of the disease depended on the level of acquired [[immunity]] of the population. When populations were exposed to the disease for the first time, all ages would be infected. In [[endemic]] regions, where there was some previous level of [[immunity]], children and young adults were the most 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> | ||
==Gender== | ==Gender== | ||
[[Smallpox]] affected males and females equally. | [[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> | ||
==Race== | ==Race== | ||
Despite potential racial susceptibility, differences in [[incidence]] of the disease according to the race were never demonstrated. | Despite potential racial susceptibility, differences in [[incidence]] of the disease according to the race were never demonstrated.<ref name=WHO>{{cite web|title=The epidemiology of smallpox|url = http://whqlibdoc.who.int/smallpox/9241561106_chp4.pdf}}</ref> | ||
==Developed Countries== | ==Developed Countries== | ||
Developed countries, due to a better established health system had lower incidence of smallpox and better reports of the new cases to the international organizations. | Developed countries, due to a better established health system had lower incidence of smallpox and better reports of the new cases to the international organizations.<ref name=WHO>{{cite web|title=The epidemiology of smallpox|url = http://whqlibdoc.who.int/smallpox/9241561106_chp4.pdf}}</ref> | ||
==Developing Countries== | ==Developing Countries== | ||
In some countries, particularly in developing countries, healthcare facilities were distrusted by the populations, hence some cases were hidden from public health authorities. Also, some religious beliefs were agains vaccination. Some of these factors might explain the higher incidence of smallpox in these countries. | In some countries, particularly in developing countries, healthcare facilities were distrusted by the populations, hence some cases were hidden from public health authorities. Also, some religious beliefs were agains vaccination. Some of these factors might explain the higher incidence of smallpox in these countries.<ref name=WHO>{{cite web|title=The epidemiology of smallpox|url = http://whqlibdoc.who.int/smallpox/9241561106_chp4.pdf}}</ref> | ||
==References== | ==References== | ||
Revision as of 20:21, 10 July 2014
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: João André Alves Silva, M.D. [2]
Overview
The true incidence of smallpox, before declared eradicated in 1980 by the WHO, wasn't possible to specify due to the great lack of reports of new cases from countries, particularly from the endemic regions, in which the reported numbers are stipulated to be 1-2% of the reality. Children and young adults were the most affected, especially in regions with low level of immunity. There is no evidence of gender or race difference in the incidence of the disease. Developing countries had a higher incidence of the disease.[1]
Incidence
The number of cases reported to the international health authorities varied greatly in accuracy. The data obtained from non-endemic countries, with good health services were probably more accurate. According to the Intensified Smallpox Eradication Programme, the reported incidence amounted to 1-2% of the reality, therefore it is not possible to obtain a true number on the incidence.[1]
Even in endemic regions there were periods called epidemic years in which the incidence was much higher. For this difference several possibilities were evoked, such as:
- Viability of the virus
- Changes in susceptibility of the host
- Social factors such as dispersion of the population
- Seasonable variation in incidence in relation to eradication
Age
The age incidence of the disease depended on the level of acquired immunity of the population. When populations were exposed to the disease for the first time, all ages would be infected. In endemic regions, where there was some previous level of immunity, children and young adults were the most affected.[2][1]
Gender
Smallpox affected males and females equally.[1]
Race
Despite potential racial susceptibility, differences in incidence of the disease according to the race were never demonstrated.[1]
Developed Countries
Developed countries, due to a better established health system had lower incidence of smallpox and better reports of the new cases to the international organizations.[1]
Developing Countries
In some countries, particularly in developing countries, healthcare facilities were distrusted by the populations, hence some cases were hidden from public health authorities. Also, some religious beliefs were agains vaccination. Some of these factors might explain the higher incidence of smallpox in these countries.[1]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 "The epidemiology of smallpox" (PDF).
- ↑ "Smallpox".