A seroepidemiological survey of viral hepatitis in the Yemen Arab Republic

Hepatitis delta: the rediscovery

Hepatitis D is returning to western Europe through immigration. The clinical presentation recapitulates the typical features of a florid hepatitis D. Hepatitis D is also being rediscovered in the developing world and in the United States. Hepatitis D virus (HDV) remains endemic in many countries and efforts are underway to map the infection at local levels and improve the medical alert to hepatitis D. In the United States it is generally thought that HDV has gone and hepatitis D is no longer a problem. Awareness of hepatitis D in the country has recently been revived.

Prevalence of hepatitis d in the eastern mediterranean region: systematic review and meta analysis

BACKGROUND

Hepatitis D Virus (HDV) causes the most threatening form of chronic viral hepatitis. To date, there is no overall estimation of HDV prevalence in the Eastern Mediterranean Region Office of WHO (EMRO) countries.

OBJECTIVES

To provide a clear estimation of HDV prevalence in the aforementioned region.

PATIENTS AND METHODS

In the current systematic review, databases such as PubMed, Embase, Web of sciences and Google scholar were searched Until December 2010. The summary estimate of HDV prevalence in the EMRO region was calculated as an average of the pooled infection prevalence of each country weighted by the ratio of the country's HBV population to the study's sample size in the survey data analysis.

RESULTS

We included 62 eligible studies. The weighted mean of HDV prevalence in the EMRO region was 14.74% (95% CI: 14.73 - 14.77), 27.8% (95% CI: 27.78 - 27.82), 36.57% (95% CI: 36.55 - 36.59) and 16.44%. (95% CI: 16.42 - 16.46) in asymptomatic HBsAg positive carriers, chronic hepatitis patients, cirrhosis/ hepatocellular carcinoma, and high risk group, respectively. Among the asymptomatic HBsAg positive group, HDV prevalence was increased by years in older patients in Saudi Arabia but its prevalence was decreased in Iran. No specific pattern was seen according to chronological analysis during years among the EMRO countries.

CONCLUSIONS

HDV infection is endemic in the EMRO countries and it is more common among patients with severe forms of hepatitis. Due to the high HDV infection rates in the EMRO countries, we recommend blood screening for HDV infection in this region.

Hepatitis B virus carrier rate, prevalence and susceptibility and impact of immunization program among households in the city of Taiz, Yemen

OBJECTIVE

To examine the carrier rate, prevalence and susceptibility to hepatitis B virus infection in the city of Taiz, Yemen.

METHODS

In a community-based household survey 521 subjects from 98 randomly selected households were enrolled. Carrier rate, prevalence and susceptibility of hepatitis B virus infection in the city of Taiz, Yemen were examined.

RESULTS

The median age of the subjects was 19 years (range <1-85 years), 219 (42.0%) of whom were males and 305 (58.0%) were females. The HBsAg carrier rate was 4.2% (22/521), the prevalence was 16.9% (88/521) and the susceptibility rate was 57.5% (287/499). Male vs female carrier rate, prevalence and susceptibility rate were comparable. Children (age ≤ 18 years) vs adults had carrier rates of 2.7% vs 5.7% (odds ratio=2.2) and a prevalence of 5.1% vs 28.4% (OR: 5.6). The carrier rate, prevalence and immunity to HBV among subjects who reported vaccination vs those unvaccinated was; 2.1% vs 5.5%, 11.3 vs 20.8% and 53.1% vs 18.8%. A proportion of 47.2% of subjects who aged ≤ 10 years had isolated anti-HBs. Of 142 of the cohort born after full implementation of vaccination program (age:≤ 9 years) 72 (50.7%) were immune and 70 (49.3%) were susceptible whereas of 357 subjects borne before program implementation (Age:≥ 10 years) 140 (39.2%) were immune and 217 (60.8%) were susceptible (p<0.02 (Pearson) OR: 1.6 CI=0.42-0.93).

CONCLUSIONS

An intermediate endimicity was identified in Taiz city. Vaccination reduced carrier rate prevalence and susceptibility among vaccinated subjects. The high rate of subjects with isolated anti- HBs together with the reduced susceptibility rate among the cohort born after inclusion of HBV vaccine to EPI reflects impact of the program. Improving vaccination coverage will further reduce susceptibility rate.

Seroepidemiology and risk factors of hepatitis B virus in Aden, Yemen

BACKGROUND

There is little published data concerning hepatitis B virus (HBV) infection in Aden and no data concerning risk factors for infection. This study aimed to determine the prevalence of HBV infection and risk factors for infection in Aden, Yemen.

METHODS

A prospective cross sectional survey of individuals attending primary health care facilities was stratified by age and population size. Five hundred and thirty five participants were interviewed and serum was screened for the presence of Immunoglobin G HBV core antibodies (antiHBc). AntiHBc positive participants were tested for antibodies to hepatitis B surface antigen (HBsAg). A case-control analysis of risk factors for HBV was undertaken comparing risk factors between antiHBc positive cases and seronegative controls.

RESULTS

The age-standardized seroprevalence for antiHBc was 16.2% (95% confidence interval (CI) 13.1-19.3) and for HBsAg was 1.5% (95% CI 0.5-2.5). The seroprevalence of antiHBc and HBsAg was estimated to range from 5.5% and 0% in infants to 40% and 4.6% in adults, respectively (p<0.001). Age (AOR=1.03, 95% CI=1.01-1.05), household size (>5-9 members, AOR=2.9, 95% CI=1.1-7.6) and ownership of a landline telephone (AOR=2.8, 95% CI=1.3-5.8) were independent risk factors for HBV infection.

CONCLUSIONS

HBV is still a public health problem in this community, with older individuals having much higher prevalence than younger generations. The results of this study would categorise Aden as a low HBV endemic zone. Perinatal transmission does not seem to be a major route of transmission.

Seroepidemiology of hepatitis A and hepatitis E viruses in Aden, Yemen

The burden of hepatitis A (HAV) and hepatitis E (HEV) infection is unknown in Aden, Yemen. This survey describes the prevalence of antibodies against HAV and HEV among individuals attending primary health care facilities in Aden, Yemen. Five hundred and thirty eight participants, stratified by age and district population size, were enrolled and screened for anti-HAV and 356 for anti-HEV antibodies. The age-standardized seroprevalence of antibodies was 86.6% (95% CI 83.7-89.5) for anti-HAV and 10.7% (95% CI 7.5-13.9) for anti-HEV. The prevalence of anti-HAV and anti-HEV ranged from 53% and 0% in infants to 100% and 15.3% in participants >18 years old, respectively (P<0.001). Viral hepatitis remains a major public health problem in Aden with trends of hyperendemicity for both infections. Priority should be given to improve water quality, sanitation coverage, and food hygiene and increase public health awareness concerning the risk of contracting infection.

Seroprevalence of markers of viral hepatitis in Yemeni healthcare workers

The seroprevalence of viral hepatitis in healthcare workers has important public health implications. To assess the risk factors for the acquisition of viral hepatitis in an unvaccinated cohort from an hyperendemic region, 567 healthcare workers from a large hospital in the capital of the Republic of Yemen were interviewed and tested for serological markers of infection with viral hepatitis. 54/543 (9.9%) tested positive for hepatitis B surface antigen (HBsAg), 174/543 (32.0%) had positive hepatitis B core antibodies (anti-HBc), and 19/546 (3.5%) had hepatitis C antibodies (anti-HCV). Age (OR = 1.04, 95% CI 1.02-1.06), male sex (OR = 2.0, 1.32-3.03), and occupation (healthcare workers not carrying out exposure prone procedures, OR = 1.61, 1.06-2.44) were found to be independent predictors for the likelihood of detecting either HBsAg or anti-HBc by multivariate logistic regression analysis. No independent risk factors for anti-HCV positive status were identified. Our findings support the adoption of universal HBV immunisation programmes and infection control precautions. The absence of known risk factors predicting anti-HCV positive serostatus suggests the main mode of transmission of hepatitis C in this cohort in the Yemen remains undiscovered.

Increase in susceptibility of young adults to hepatitis B infection in the Republic of Yemen

Susceptibility to hepatitis B virus (HBV) infection among 987 young adult male blood donors in 2 major Yemeni cities was investigated. Hepatitis B surface antigen (HBsAg) was detected in 10.8% (107/987) of donors and 284 (28.8%) had evidence of ongoing or past HBV infection. Hepatitis B surface antibody (anti-HBs) only was detected in 34 (3.4%) donors. Thus, 67.8% (669/987) of donors had no detectable HBV-markers indicating susceptibility to infection. The proportion of HBV-susceptible donors decreased from 70.9% (249/351) in donors aged < 25 years to 69.4% (334/481) in those aged 25-34 years and 55.5% (86/155) in donors aged > 34 years (P = 0.002). The high proportion of susceptible young adults in a community with a high HBsAg carrier rate could be the result of changing epidemiology of hepatitis B in Yemen. Consideration should therefore be given to immunizing young adults as an adjunct to the current expanded infant immunization programme.

Two distinct types of hepatitis B virus core promoter variants in Yemeni blood donors

Genetic variations in the basic core promoter (BCP) region of hepatitis B virus (HBV) occur during the natural history of chronic HBV infection. This study investigates the presence of basic core promoter variations in 28 asymptomatic Yemeni blood donors, correlating variations with HBeAg phenotype and viral load. The core promoter/precore and surface gene region of HBV DNA were amplified using nested PCRs and the PCR products were sequenced either directly or after cloning. HBeAg and viral load were measured when HBV DNA was detectable. Sequencing of 18 surface PCR products indicated that all were of genotype D. Two distinct types of variants were identified in the basic core promoter: substitution only (N = 14) and major deletion (N = 9). The commonest substitutions were located at nucleotide positions 1753, 1762, and 1764; 10/14 (71.4%) were associated with the precore 1896A substitution resulting in the premature stop of the precore reading frame and 6/14 (42.9%) had viral loads above 400 copies/ml. Two forms of deletion variants were found: 8 bp deletion (1763-1770) (N = 2) and a novel 12 (1746-1757) + 8 bp (1763-1770) deletion (N = 7). The deletion sequences were never associated with the precore 1896A substitution and all had viral load below 400 copies/ml with negative HBeAg phenotype. The polymorphism 1773C was found in 9/14 (64.3%) substitution sequences whereas all deletion sequences had 1773T. Two donors had mixed sequences of basic core promoter substitution and major deletions (both 8 bp and 12 + 8 bp). While the deletion variants in these two donors were similar to others found in isolation, the substitutions were of a different pattern. Further studies are required to understand the selection process behind these variants.

Acute sporadic hepatitis in the Republic of Yemen

The causes of acute icteric viral hepatitis were determined in 78 adult Yemeni patients. Acute hepatitis B (IgM anti-HBc positive) was the most common type (26.9%). Acute hepatitis E (IgM anti-HEV positive) occurred in 14% and was not associated with travel outside Yemen. Sixty percent of all 78 patients were positive for IgG anti-HEV as were 40% of a series of 48 healthy male blood donors and pregnant females, indicating that HEV is prevalent in Yemen. Acute hepatitis A (IgM anti-HAV positive) and hepatitis C and D were responsible for 5.1%, 6.4%, and 2.6% cases, respectively. This totals to 106%, as an infection with two viruses occurred in 6.4% cases. In 51.3% of all cases, no virological markers of acute hepatitis were detected, suggesting an as yet undiscovered agent.

Prevalence of hepatitis B, C, and D virus markers in Yemeni patients with chronic liver disease

A serological survey for hepatitis B, C, and D markers was carried out in the Yemen Republic. Serum samples from 243 pregnant females, 294 male blood donors, and 108 patients with chronic liver disease were examined. Hepatitis B surface antigen (HBsAg) was found in 18.5% healthy individuals and 24.1% patients with chronic liver disease (P = 0.03). Evidence of any marker for hepatitis B virus (HBV) infection was found in 59.8% healthy individuals and 75.9% of patients with chronic liver disease (P = 0.0016). HBeAg was detected in 32.1% of the HBsAg-positive pregnant females, indicating that vertical transmission probably plays a part in forming the pool of HBV carriers. Vaccination against HBV as part of the extended programme of immunisation (EPI) is recommended. Antibodies to hepatitis D were found in only 2 of 100 HBsAg-positive sera. Antibodies to hepatitis C (anti-HCV) were found in 2.1% healthy individuals and 21.5% patients with chronic liver disease (P = 0.0001). These results indicate that hepatitis B is hyperendemic in the Yemen Republic but that hepatitis D is very uncommon. The prevalence of anti-HCV is higher than in Europe and similar to neighbouring Arab countries. Infection with both HBV and HCV are important causes of chronic liver disease in the Yemen Republic.

Delta hepatitis: molecular biology and clinical and epidemiological features

Hepatitis delta virus, discovered in 1977, requires the help of hepatitis B virus to replicate in hepatocytes and is an important cause of acute, fulminant, and chronic liver disease in many regions of the world. Because of the helper function of hepatitis delta virus, infection with it occurs either as a coinfection with hepatitis B or as a superinfection of a carrier of hepatitis B surface antigen. Although the mechanisms of transmission are similar to those of hepatitis B virus, the patterns of transmission of delta virus vary widely around the world. In regions of the world in which hepatitis delta virus infection is not endemic, the disease is confined to groups at high risk of acquiring hepatitis B infection and high-risk hepatitis B carriers. Because of the propensity of this viral infection to cause fulminant as well as chronic liver disease, continued incursion of hepatitis delta virus into areas of the world where persistent hepatitis B infection is endemic will have serious implications. Prevention depends on the widespread use of hepatitis B vaccine. This review focuses on the molecular biology and the clinical and epidemiologic features of this important viral infection.

Schistosomiasis mansoni in Yemen: A review

Schistosomiasis is a major public health problem in Yemen. In 1922 Schistosomiasis mansoni was first reported to be found in Yemeni patients. In 1951 the first population survey was carried out in Taiz and revealed the presence of Biomphalaria biossyi arabica where 35% of the snails were heavily infected with S. mansoni and in San'a no snails were infected. Although S. mansoni and S. hematobium infections have been found in most parts of Yemen Arab Republic (YAR) it seems that the disease is not a public health problem in some parts of the country such as Hodeidah, Al-Beidah, Mareb, and Al-Gouff. The source of S. mansoni and S. hematobium in Yemen was attributed to the continual migration of infected persons from Eritrea and other countries of East Africa to Yemen. The prevalence of infection is higher in rural than in urban areas. The complications of S. mansoni, notably portal hypertension, esophageal varices, and hematemesis have become a major clinical problem. The availability of Praziquantel as a safe and effective treatment makes case findings and treatment an important part of schistosomiasis control. Control of the disease also requires field studies followed by mollusciding, improvement of water supply and sanitation and, perhaps most importantly, health education.