Epidemiology of viruses causing chronic hepatitis among populations from the Amazon Basin and related ecosystems

Abstract

On the last twenty years, viral hepatitis has emerged as a serious problem in almost all the Amerindian communities studied in the Amazon Basin and in other Amazon-related ecological systems from the North and Center of South America. Studies performed on communities from Bolivia, Brazil, Colombia, Peru and Venezuela have shown a high endemicity of the hepatitis B virus (HBV) infection all over the region, which is frequently associated to a high prevalence of infection by hepatitis D virus among the chronic HBV carriers. Circulation of both agents responds mainly to horizontal virus transmission during childhood through mechanisms that are not fully understood. By contrast, infection by hepatitis C virus (HCV), which is present in all the urban areas of South America, is still very uncommon among them. At the moment, there is not data enough to evaluate properly the true incidence that such endemicity may have on the health of the populations affected. Since viral transmission might be operated by mechanisms that could not be acting in other areas of the World, it seems essential to investigate such mechanisms and to prevent the introduction of HCV into these populations, which consequences for health could be very serious.

Hepatitis B Infection and Association with Other Sexually Transmitted Infections Among Men Who Have Sex with Men in Peru

“…2 Most of these people are in the developing world where intermediate (2-8% and 15-40%) to high (> 8% and > 40%) endemic areas (based on prevalence of hepatitis B surface antigen [HBsAg] and total antibodies to hepatitis B core antigen [anti-HBc], respectively) have been recognized, mostly reflecting people becoming horizontally infected during childhood through mechanisms not fully understood. In almost all Amerindian communities of the Amazon Basin and certain areas of the Andes in Peru, high rates of chronic HBV infection have been described [3][4][5] with associated high morbidity and mortality rates. [6][7][8][9][10] Persons with chronic HBV infection (defined as those with serologic evidence of HBsAg for a period of at least 6 months) are the major reservoir for transmission, although any HBsAgpositive person is potentially infectious.…”

Serological markers of hepatitis A, B and C viruses in rural communities of the semiarid Brazilian Northeast

“…In contrast, there is a high prevalence of hepatotrophic viruses in the Amazon region with virological peculiarities, such as genotype F of HBV [8,9] and hepatitis D virus [10]. Many Brazilian studies, as well as international studies, describe the prevalence of hepatotrophic viruses among specific groups, such as blood donors [11], patients in hemodialysis programs [12][13][14], hemophiliacs [15], afro-descendants [16], mental disease patients [17] and hepatitis patients [18,19].…”

Ecosystem approaches and health in Latin America

“…Of these, four adopt a vector ecology approach 7,8,9,10 ; two study the interface between vector ecology and the ecosystem as a modified place 11,12 ; eight deal with the ecosystem as a place that has been modified and become disease-prone 13,14,15 , in which viruses are present 16,17 , where diseases occur 18,19 , and as the place in which intervention should occur 20 ; and nine adopt ecosystem approaches which in some way include the premises laid out in the WRI report 1 . Only one of the nine studies was published by a Brazilian researcher 3 .…”