Serological tests for antibodies specific for Epstein-Barr virus (EBV) antigens are frequently used to define infection status and for the differential diagnosis of other pathogens responsible for mononucleosis syndrome. Using only three parameters [viral capsid antigen (VCA) IgG, VCA IgM and EBV nuclear antigen (EBNA)-1 IgG],it is normally possible to distinguish acute from past infection: the presence of VCA IgM and VCA IgG without EBNA-1 IgG indicates acute infection, whereas the presence of VCA IgG and EBNA-1 IgG without VCA IgM is typical of past infection. However, serological findings may sometimes be difficult to interpret as VCA IgG can be present without VCA IgM or EBNA-1 IgG in cases of acute or past infection, or all the three parameters may be detected simultaneously in the case of recent infection or during the course of reactivation. A profile of isolated EBNA-1 IgG may also create some doubts. In order to interpret these patterns correctly, it is necessary to determine IgG avidity, identify anti-EBV IgG and IgM antibodies by immunoblotting, and look for heterophile antibodies, anti-EA (D) antibodies or viral genome using molecular biology methods. These tests make it possible to define the status of the infection and solve any problems that may arise in routine laboratory practice.

Long-term follow up studies of hepatitis C virus (HCV) infection

This cohort study examines the rate of SARS-CoV-2 reinfection among people in Lombardy, Italy, who previously recovered from COVID-19.

The presence of VCA IgG in the absence of VCA IgM and EBNA-1 IgG antibodies makes classifying EBV infection more difficult as this serological picture can be seen in the case of past infection with EBNA-1 IgG loss or non-appearance, or acute infections with the early disappearance or delayed onset of VCA IgM. The aim of this study was to assess the prevalence of this pattern in 2,422 outpatients with suspected EBV infection examined in 2005-2006, and to interpret its significance by means of immunoblotting. One hundred and seventy-seven (7.3%) of the patients were VCA IgG-positive, VCA IgM-negative and EBNA-1 IgG-negative, 15 of whom (8.5%) presented with heterophile antibodies. Analysis by age class showed that the prevalence of isolated VCA IgG ranged from 4.5% in the subjects aged 1-10 years to 9% in those aged >60 years. Immunoblotting allowed 18.9% of the cases to be classified as acute and 81.1% as past infections, the latter being observed in about 37% of the patients aged less than 10 years and in 100% of those aged >30 years. Therefore, in our case series, the presence of isolated VCA IgG was associated usually with past infection, particularly among adults. In children aged less than 10 years, it was associated mainly with acute infection but as past infection may be present in about one-third of such children, this possibility should not be overlooked.

Pregnant women are not screened for HBsAg and anti-HCV antibodies in many African countries. As there are few data concerning the prevalence of HBV, HDV, and HCV serological markers in Benin, the aim of this study was to evaluate their 2011 prevalence in pregnant women undergoing HIV screening in a rural area of north Benin, and compare the data with those reported for the same area in 1986. The sera of 283 women were examined for HBsAg, anti-HBs, anti-HBc, anti-HCV, and anti-HIV 1/2 antibodies. In the case of HBsAg positivity, a search was made for the HBeAg, anti-HDV, and HBV genotypes; in the case of anti-HCV positivity, a search was made for the HCV genotypes. HBsAg, anti-HBs, anti-HBc, anti-HCV, and anti-HIV 1/2 were positive in respectively 44 (15.5%), 82 (29.0%), 234 (82.7%), 21 (7.4%), and nine samples (3.2%). Of the HBsAg-positive samples, five (11.4%) were positive for HBeAg, five (11.4%) for anti-HDV, and 19 for HBV genotype E. Of the anti-HCV-positive samples, five were positive for genotype 2a/2c and one for genotype 1a. The prevalence of anti-HBc alone (HBsAg and anti-HBs negative) was very high (41.3%). In comparison with the 1986 data, the prevalence of HBsAg and anti-HBc remained unchanged, that of HBeAg and anti-HDV had decreased, and that of anti-HIV 1/2 had increased. As these data confirm that HBV and HCV are highly endemic in the study area, it may be appropriate to introduce HBsAg and anti-HCV screening for pregnant women. J. Med. Virol. 86:1281-1287, 2014. © 2014 Wiley Periodicals, Inc.