Hepatitis A virus in West Africa: Is an epidemiological transition beginning?

Abstract

Background:Studies of hepatitis A virus (HAV) seroprevalence in sub-Saharan Africa have generally found very high anti-HAV IgG seroprevalence rates, but economic development and improved drinking water access may be contributing to decreasing incidence.Materials and Methods:This review evaluates all 19 articles that have been published on HAV epidemiology in West Africa.Results:Nearly all studies conducted before 1990 found that the majority of preschool-aged children had already developed immunity due to prior infection. However, several recent studies have observed that the age at midpoint of population immunity in some urban populations has shifted to school-aged children.Conclusion:There is preliminary evidence that some West-African countries are beginning the transition towards lower hepatitis A endemicity levels. Additional studies of child seroprevalence rates in diverse parts of West Africa are required in order to clarify the extent to which an early transition may be occurring.

Progress Toward Eliminating Hepatitis A Disease in the United States

“…These NHANES estimates suggest that a large proportion of the U.S. adult population is susceptible to acute HAV at ages when the risk for illness and death is greatest. HAV remains endemic in much of the world (9,12,13,57). International travel and the global food economy create conditions that could contribute to HAV infection among an increasingly susceptible U.S. adult population.…”

“…Since the introduction of the HepA vaccine, ACIP has recommended HepA vaccination as a control measure in Rate outbreaks, for populations at increased risk, for persons who have chronic liver disease, as routine vaccination for children aged 12-23 months and for anyone wishing to obtain immunity (Box) (3,6,18 Risk for infection for unvaccinated persons is related to the prevalence of HAV in the community (9,11,12). The 1996 ACIP recommendations were directed at controlling outbreaks and preventing HAV infection in high-risk persons (3).…”

“…The epidemiology of acute HAV disease varies worldwide and is in transition in many areas (8)(9)(10)(11)(12). In regions where HAV infection has been considered endemic (e.g., Africa, Asia, Central and South America, and Eastern Europe), up to 90% of children are infected by age 10 years (13).…”

Demographic Study on Hepatitis A Infections among Outpatients of Selected Hospitals within Kaduna Metropolis, Nigeria

“…Unlike Hepatitis B and C infections with asymptomatic cases, HAV infected persons often show symptoms of the virus [9]. Common symptoms associated with Hepatitis A infections include: Anorexia, nausea, vomiting, jaundice, dark urine, pale feces and elevated liver transaminase levels among others [5][6][7][8][9][10][11] The Hepatitis A Virus which is a member of the genus Hepatovirus of the Picornaviridae family has a small, naked icosahedral capsid and a single stranded (+ Strand) RNA consisting of approximately 7470 nucleotides [10][11][12][13]. The Virus is very resistant to chemical and physical agents and several minutes of boiling may be necessary to inactivate it [4].…”

“…The transmission of the virus is primarily through fecally contaminated foods and drinks and has also been associated with outbreaks among injection drug users, men who have sex with men and food handlers [4][5][6][7]. Though the virus causes a milder form of hepatitis which is self-limiting with a lifelong immunity and absence of chronic form, the dangers of debilitating symptoms and fulminant hepatitis (acute liver failure) by the virus still remains a point of concern [5,8]. Unlike Hepatitis B and C infections with asymptomatic cases, HAV infected persons often show symptoms of the virus [9].…”