Epitope-based recombinant diagnostic antigen to distinguish natural infection from vaccination with hepatitis A virus vaccines.

Hepatitis A virus (HAV) infection can stimulate the production of antibodies to structural and non-structural proteins of the virus. However, vaccination with an inactivated or attenuated HAV vaccine produces antibodies mainly against structural proteins, whereas no or very limited antibodies are produced against the non-structural proteins. Current diagnostic assays to determine exposure to HAV, such as the Abbott HAV AB test, detect antibodies only to the structural proteins and so are not able to distinguish a natural infection from vaccination with an inactivated or attenuated virus. Here, we constructed a recombinant tandem multi-epitope diagnostic antigen (designated 'H1') based on the immune-dominant epitopes of the non-structural proteins of HAV to distinguish the two situations. H1 protein expressed in Escherichia coli and purified by affinity and anion exchange chromatography was applied in a double-antigen sandwich ELISA for the detection of anti-non-structural HAV proteins, which was confirmed to distinguish a natural infection from vaccination with an inactivated or attenuated HAV vaccine.

Experimental hepatitis A virus (HAV) infection in cynomolgus monkeys (Macaca fascicularis): evidence of active extrahepatic site of HAV replication.

This work studied the replication sites of hepatitis A virus (HAV) in cynomolgus monkeys (Macaca fascicularis) after intravenous inoculation. The cynomolgus monkeys were inoculated with the Brazilian hepatitis A virus strain (HAF-203). Monkeys were euthanized on days 15, 30, 45 and 60 postinoculation (pi). Liver samples, submandibular salivary gland, mesenteric lymph node and tonsils were removed for virological and pathological evaluation. Immunofluorescence analyses on liver and salivary gland sections using confocal laser scanning microscopy revealed the presence of HAV antigen (HAV Ag). The presence of HAV genome was monitored by real-time PCR. The HAV RNA was detected at 7 days postinoculation (dpi), concomitantly in serum, saliva and faeces. The highest HAV viral load was observed in faeces at 15 dpi (10(5) copies/ml), followed by serum viral load of 10(4) copies/ml at 20 dpi and saliva viral load of 10(3 )copies/ml at 7 dpi. The animals showed first histological and biochemical signs of hepatitis at 15 dpi. The HAV antigen (Ag) was present from day 7 until day 60 pi in the liver and salivary glands. The HAV replicative intermediate was also detected in the liver (4.5 x 10(4) copies/mg), salivary glands (1.9 x 10(3) copies/mg), tonsils (4.2 x 10(1) copies/mg) and lymph nodes (3.4 x 10(1) copies/mg). Our data demonstrated that the salivary gland as an extrahepatic site of early HAV replication could create a potential risk of saliva transmitted infection. In addition, the cynomolgus monkey was confirmed as a suitable model to study the pathogenesis of HAV human infection.

Seroprevalencia de las hepatitis virales en población general representativa de una zona básica de salud urbana en Castilla y León / Seroprevalence of viral hepatitis in a representative general population of an urban public health area in Castilla y León (Spain)

Introducción. Las hepatitis virales constituyen uno de los principales problemas sociosanitarios y económicos a nivel mundial por lo que precisan un estrecho control epidemiológico. Métodos. En el presente trabajo estudiamos la seroprevalencia de las hepatitis virales una muestra representativa de la población de una zona básica de salud urbana en Valladolid (España). Resultados. La prevalencia de anticuerpos anti-VHA (AcVHA) fue del 52%, de HBcAc del 8,2%, de AcVHC del 1,1%, de AcVHE 0,8% y AcVHG 5,8%. La prevalencia de AcVHA, HBcAc y AcVHG aumenta significativamente con la edad (p < 0,005 en todos los casos). En menores de 20 años la prevalencia de AcVHA es del 3,8%, HBcAc < 0,28% y AcVHG 1,3%. En el grupo de edad de 20-39 años, la seroprevalencia frente al VHA se asocia con niveles educativos bajos (p 5 0,009) y con el nacimiento en otras provincias (p 5 0,016). La seroprevalencia de HBcAc se asocia principalmente con hospitalizaciones anteriores a 1990 (p 5 0,002; OR: 3,32 [1,48-7,42]), realización del servicio militar obligatorio anterior a 1990 (p < 0,0001; OR: 37,33 [3,68-378,03]) y prácticas de acupuntura (p 5 0,018; OR: 57,75 [26,17-127,42]). La seroprevalencia frente a VHG se asocia con hospitalizaciones antes de 1990 (p 5 0,019; OR: 2,969 [1,154-7,639]). Los seropositivos frente a VHC tenían antecedentes de transfusiones (2 casos) hospitalización (1 caso) o drogadicción (1 caso). De los seropositivos frente a VHE sólo un caso tenía antecedentes de viaje a zona endémica para VHE. Conclusiones. Nuestro estudio muestra que las seroprevalencias de las hepatitis virales en una muestra representativa de población urbana de Castilla y León son similares a las seroprevalencias obtenidas en el resto de España y de los países desarrollados, inferior a la observada en los estudios realizados en España en los últimos 20 años consecuencia de las medidas profilácticas adoptadas (AU)

Introduction. Viral hepatitis is a major social, health and economic problem worldwide, requiring strict epidemiological control. Methods. This study presents the viral hepatitis seroprevalence in a representative sample from an urban health care area in Valladolid (Spain). Results. Antibody prevalence was as follows: anti-HAV 52%; anti-HBc, 8.2%; anti-HCV, 1.1%; anti-HEV, 0.8%; and anti-HGV 5.8%. Prevalence of anti-HAV, anti-HBc and anti-HGV increased significantly with age (P < 0.005 in all cases). In individuals younger than 20, prevalence of anti-HAV was 3.8%, anti-HBc < 0.28% and anti-HGV 1.3%. In the 20-39 year-old group, seroprevalence against HAV was associated with low educational levels (P 5 0.009) and with birth in other provinces (P 5 0.016). Anti-HBc seroprevalence was mainly associated with three factors: prior hospitalization before 1990 (P 5 0.002; OR 3.32 [1.48-7.42]); compulsory military service before 1990 (P < 0.0001; OR 37.33 [3.68-378.03]); and acupuncture treatments (P 5 0.018; OR 57.75 [26.17-127.42]). Seroprevalence against HGV was associated with hospitalizations before 1990 (P 5 0.019; OR 5 2.969 [1.154-7.639]). Seropositive status to HCV revealed a transfusion history (2 cases), hospitalization (1 case) or drug addiction (1 case). Only one case among those seropositive to HEV had a history of a prior trip to a HEV-endemic area. Conclusions. Our study shows that the seroprevalences of viral hepatitis in a representative sample of urban population of Castille and Leon are similar to the seroprevalences observed in the rest of Spain and other developed countries, lower than the ones observed in the studies performed in Spain in the last 20 years due to the measures of prophylaxis that werw taken (AU)