One estimate places  the number as high as 3 million cases per year.Estimates of Lassa fever are complicated by the lack of easy-available diagnosis, limited public health surveillance infrastructure, and high clustering of incidence near high intensity sampling.The infection affects females 1.2 times more than males. The age group predominantly infected is 21–30 years. Geography
Lassa high risk areas are near the western and eastern extremes of West Africa. As of 2018, the Lassa belt includes Guinea, Nigeria, Sierra Leone and Liberia. As of 2003, 10-16% of people in Sierra Leone and Liberia admitted to hospital had the virus. The case fatality rate for those who are hospitalized for the disease is about 15-20%. Research showed a twofold increase risk of infection for those living in close proximity to someone with infection symptoms within the last year. The high risk areas cannot be well defined by any known biogeographical or environmental breaks except for the multimammate rat, particularly Guinea (Kindia, Faranah and Nzérékoré regions), Liberia (mostly in Lofa, Bong, and Nimba counties), Nigeria (in about 10 of 36 states) and Sierra Leone (typically from Kenema and Kailahun districts). It is less common in the Central African Republic, Mali, Senegal and other nearby countries, and less common yet in Ghana and the Democratic Republic of the Congo. Benin had its first confirmed cases in 2014, and Togo had its first confirmed cases in 2016.As of 2013, the spread of Lassa outside of West Africa had been very limited.
However, EEs and CEEs differ in the sources of their contents and in the percentages of their constituents; CEEs consist of approximately 53% sodium estrone sulfate and 25% sodium equilin sulfate, while EEs contain about 75 to 85% sodium estrone sulfate and 6 to 11% sodium equilin sulfate. EEs have been found to produce similar serum levels of estrone and estradiol relative to CEEs, although with higher levels of estrone and lower levels of equilin. One study found that the risk of venous thrombosis may be less with EEs relative to CEEs. Chemistry
EEs contain synthetic, plant-derived estrogens and are manufactured from soybeans and yams. History
EEs were introduced for medical use by 1970. Society and culture
Generic names
Estrogens, esterified is the generic name of the drug and its USP. It is also known as esterified estrogens. Brand names
EEs are marketed under a variety of brand names including Amnestrogen, Estragyn, Estratab, Evex, Femibel, Femogen, Menest, Neo Estrone Tab, and Oestro-Feminal alone, and, in combination with methyltestosterone, under the brand names Covaryx, Delitan, Eemt, Essian, Estratest, Feminova-T, Menogen, and Syntest. Availability
EEs are or have been marketed in Argentina, Chile, Switzerland, and the United States. Both EEs and the combination of EEs and methyltestosterone are listed as being marketed only in Chile and the United States as of present. See also
Esterified estrogens/methyltestosterone
Estrogenic substances
Conjugated estriol
List of combined sex-hormonal preparations


== References ==