No single diagnostic test for cytomegalovirus (CMV) infection is currently available for pregnant women at all stages of gestation. Improved accuracy in estimating the timing of primary infections can be used to identify women at higher risk of giving birth to congenitally infected infants. A diagnostic algorithm utilizing immunoglobulin G (IgG), IgM, and IgG avidity was used to prospectively screen serum from 600 pregnant women enrolled from two groups: <20 weeks gestation (n ‫؍‬ 396) or >20 weeks gestation (n ‫؍‬ 204). PCR testing of urine and/or blood was performed on all seropositive women (n ‫؍‬ 341). The majority (56.8%) of women were CMV IgG seropositive, with 5.5% being also CMV IgM positive. In the IgM-positive women, 1.2% had a low-avidity IgG, indicating a primary CMV infection and a high risk of intrauterine transmission. Two infants with asymptomatic CMV infection were born of mothers who had seroconverted in the second trimester of pregnancy. Baseline, age-stratified CMV serostatus was established from 1,018 blood donors. Baseline seropositivity from a blood donor population increased with age from 34.9% seroprevalence at less than 20 years of age to 72% seroprevalence at 50 years of age. Women at high risk of intrauterine transmission of CMV were identified at all stages of gestation. Women infected with CMV during late gestation may be more likely to transmit the virus, so failure to detect seroconversions in late gestation may result in failure to detect infected neonates.Human cytomegalovirus (CMV) is the most common cause of congenital malformation resulting from viral intrauterine infection in developed countries (12,21,48). Primary CMV infection occurs in 0.15 to 2.0% of all pregnancies and may be transmitted to the fetus in up to 40% of cases (48). Up to 15% of intrauterine CMV infections result in symptomatic congenital disease at birth, and 10 to 15% of those born with asymptomatic congenital CMV will develop significant clinical sequelae in infancy (7,10,18). In utero transmission of CMV can occur during primary maternal infection, reactivation, or reinfection of seropositive mothers. Most concern centers on primary maternal infection, due to the potential for significant fetal damage when the infection is acquired and transmitted during the first trimester (30, 48). Perinatal infections can result through virus transmission from many parts of the birth canal (39); however, the majority of these infections are asymptomatic (43).The usefulness of prenatal testing for CMV has been questioned due to the absence of clearly effective intervention (1, 27) and to evidence for severe congenital malformation resulting from viral reactivation (6,8,20). Continuing advancements in technology, however, mean reliable and inexpensive serologic tests are available, prenatal diagnostic procedures with acceptable negative predictive values (NPV) can be performed, and trials of neonatal antiviral treatments are ongoing (25,34,37,50,52). Proposed diagnostic algorithms have focused on first-trimester screeni...

Objectives: To determine the prevalence of hepatitis B virus (HBV) and hepatitis C virus (HCV) infection among inmates entering the New South Wales correctional system and to examine risk factors for infection. Design: Cross‐sectional survey. Setting: Reception Centre at Long Bay Correctional Centre, Sydney, New South Wales, June to December 1994. Participants: 408 adult male inmates received at the Reception Centre (28% of the 1450 new inmates eligible for compulsory HIV testing). Outcome measures: Presence of HBV core and surface antibody and surface antigen; HCV antibody; risk factors; inmates' knowledge about risk factors. Results: 37% of inmates tested positive for HCV antibody, 31% for HBV core antibody and 3.2% for HBV surface antigen (indicating recent infection or carrier status). Among those who reported a history of injecting illegal drugs, rates rose to 66% for HCV antibody and 43% for HBV core antibody. Prevalence of HBV and HCV antibodies was similar in Aboriginal and non‐Aboriginal inmates, but HBV antigen carrier rate was significantly higher among Aboriginals (12% versus 2.2%). Knowledge about hepatitis risk factors was poor (only 20% named injecting drug use), although recidivists were significantly better informed than those new to the correctional system. Multivariate analysis identified injecting drug use, past exposure to hepatitis B virus and previous imprisonments as significant predictors for HCV infection, and age over 25 years and HCV antibodies for HBV infection. Conclusions: Results suggest that about a third of adult male prisoners entering the NSW correctional system may have been infected with HBV or HCV. Measures such as education about hepatitis risk factors and HBV vaccination are needed to reduce hepatitis transmission in this population.

Current serological methods for the diagnosis of Epstein-Barr virus (EBV) infection still differentiate poorly between primary infection and reactivation. This is particularly true when IgG and IgM antibodies are present simultaneously and only a single serum sample is provided for analysis. The demonstration of the IgG avidity state has the potential to distinguish recent from past or reactivated infection. An analysis of the kinetics of avidity maturation of anti-VCA antibodies in primary EBV infection was undertaken with longitudinally collected sets of sera from 28 well-characterised EBV cases and in sera from 35 cases with previous EBV infection and recent primary infection due to HIV, CMV, or hepatitis A. Antibodies directed against the viral capsid antigen (VCA) and Epstein-Barr nuclear antigen (EBNA-1) were sought, using a commercial enzyme immunoassay (EIA). In parallel with standard IgG anti-VCA detection, serum was incubated with 8 M urea to disrupt low-avidity complexes to allow calculation of the percentage avidity. In cases with primary EBV infection, the mean avidity rose from 54% at 6 weeks to 82% by 28 weeks after the onset of symptoms, but remained lower than that of the control sera (96%). The addition of the avidity measurement improved the sensitivity of IgG and IgM anti-VCA testing in diagnosis of primary EBV infection from 93% to 100%. The specificity of IgM anti-VCA testing alone was poor, with 14 of 35 cases (49%) demonstrating false-positive results, but it improved to 97% by the demonstration of high-avidity IgG anti-VCA. The combination of negative IgG anti-EBNA and low-avidity IgG anti-VCA had a sensitivity and specificity of 100%. The routine addition of IgG anti-VCA avidity estimation to diagnostic EBV serology is recommended.

Several outbreaks of hepatitis A in men who have sex with men (MSM) were reported in the 1980s and 1990s in Australia and other countries. An effective hepatitis A virus (HAV) vaccine has been available in Australia since 1994 and is recommended for high-risk groups including MSM. No outbreaks of hepatitis A in Australian MSM have been reported since 1996. In this study, we aimed to estimate HAV transmissibility in MSM populations in order to inform targets for vaccine coverage in such populations. We used mathematical models of HAV transmission in a MSM population to estimate the basic reproduction number (R 0) and the probability of an HAV epidemic occurring as a function of the immune proportion. We estimated a plausible range for R 0 of 1·71-3·67 for HAV in MSM and that sustained epidemics cannot occur once the proportion immune to HAV is greater than ~70%. To our knowledge this is the first estimate of R 0 and the critical population immunity threshold for HAV transmission in MSM. As HAV is no longer endemic in Australia or in most other developed countries, vaccination is the only means of maintaining population immunity >70%. Our findings provide impetus to promote HAV vaccination in high-risk groups such as MSM.

Legionella pneumophila is a natural intracellular bacterial parasite of free-living freshwater protozoa and an accidental human pathogen that causes Legionnaires' disease. L. pneumophila differentiates, and does it in style. Recent experimental data on L. pneumophila's differentiation point at the existence of a complex network that involves many developmental forms. We intend readers to: (i) understand the biological relevance of L. pneumophila's forms found in freshwater and their potential to transmit Legionnaires' disease, and (ii) learn that the common depiction of L. pneumophila's differentiation as a biphasic developmental cycle that alternates between a replicative and a transmissive form is but an oversimplification of the actual process. Our specific objectives are to provide updates on the molecular factors that regulate L. pneumophila's differentiation (Section The Differentiation Process and Its Regulation), and describe the developmental network of L. pneumophila (Section Dissecting Lp's Developmental Network), which for clarity's sake we have dissected into five separate developmental cycles. Finally, since each developmental form seems to contribute differently to the human pathogenic process and the transmission of Legionnaires' disease, readers are presented with a challenge to develop novel methods to detect the various L. pneumophila forms present in water (Section Practical Implications), as a means to improve our assessment of risk and more effectively prevent legionellosis outbreaks.