Peter E. Robertson

Diagnosis of and Screening for Cytomegalovirus Infection in Pregnant Women

ABSTRACT 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.

A commercial ELISA detects high levels of human H5 antibody but cross-reacts with influenza A antibodies

BACKGROUND AND OBJECTIVES Commercial serological assays to determine influenza A H5N1 infection are available, although the accuracy and reproducibility of these are not reported in detail. This study aimed to assess the validity of a commercial ELISA H5 hemagglutinin (HA) antibody kit. STUDY DESIGN A commercial ELISA for detection of antibodies towards influenza A H5 HA was evaluated using human sera from vaccinated individuals. The ELISA was used to screen 304 sera with elevated influenza A complement fixation titres collected between the period 1995-2007. RESULTS AND CONCLUSIONS The ELISA was found to be accurate for sera with high levels of anti-H5 antibodies, and would be useful in clinical settings where a rapid result is required. Thirteen of the stored sera were positive using the ELISA, but were confirmed as negative for H5N1 exposure using further serological tests. Absorption studies suggested that antibodies towards seasonal H3N2 and H1N1 influenza may cross-react with H5 antigen, giving false positive results with the ELISA.

Demographic shocks and human capital accumulation in the Uzawa-Lucas model

Abstract The Uzawa–Lucas growth model is modified to incorporate unskilled labour as a distinct factor from human capital. The modified model is then used to discuss the effects of demographic shocks on optimal growth and human capital investment.

Enhanced diagnosis of pandemic (H1N1) 2009 influenza infection using molecular and serological testing in intensive care unit patients with suspected influenza.

During the 2009 outbreak of pandemic (H1N1) 2009 influenza (pH1N1) in Australia, acute and convalescent serum specimens were collected from 33 patients with severe respiratory disease admitted to intensive care units. Using hemagglutination inhibition of pH1N1, 29 paired serum samples showed significant increases in specific antibody titers. Of these 29 patients, 18 had pH1N1 RNA detected by routine nucleic acid testing. These results indicate that up to one-third of pH1N1 cases may not have laboratory confirmation of infection unless serological testing is included for suspected cases.

Diagnosis of Enterovirus Infection by Genus-Specific PCR and Enzyme-Linked Immunosorbent Assays

ABSTRACT PCR for the diagnosis of enterovirus infections is resource intensive but is increasingly used due to wide availability. Enzyme-linked immunosorbent assays (ELISAs) that detect heterotypical antibodies against enterovirus immunoglobulin M (IgM), IgA, and IgG were compared with reverse transcription-PCR by using primers specific to the 5′ untranslated regions of 60 enterovirus species. The ELISAs were less sensitive than the PCR, and only the ELISA for IgM was highly specific. When retrospective diagnosis is important or when specimens are unsuitable for PCR, the ELISA has a limited role if PCR is not available.

The International Effects of China’s Growth, Trade and Education Booms

China’s international trade flows have increased by 500% since 1992, far outstripping GDP growth. Likewise tertiary education enrollments have increased by 300%. We simulate these changes using a multi-sector growth model of the Chinese and USA economies. A decade of trade biased growth in China is found to have a large effect on the USA economy – raising GDP approximately 3-4.5 percentage points. We also show that the trade bias in China’s growth accounts for more than half of the observed growth in tertiary enrolments in China. In contrast neutral growth has practically no effect on USA incomes or China’s stock of skilled labour. Finally the simulations reveal that China’s education boom per se has practically no long run impact on the USA economy. The results thus indicate that the pattern of productivity growth in exports sectors, as might be caused by falling trade costs, has been critical in transmitting benefits of Chinese growth to the world economy. They also point to an important link between falling trade costs and human capital formation.

Congenital cytomegalovirus infection is associated with high maternal socio-economic status and corresponding low maternal cytomegalovirus seropositivity.

Human cytomegalovirus (CMV) is the leading infectious cause of congenital infection in developed countries. Globally, CMV seropositivity has been associated with low socio‐economic status (SES); however, Australian data are lacking. Therefore, we examined the association between SES and CMV seroprevalence in children and pregnant women.

Laboratory diagnosis, molecular characteristics, epidemiological and clinical features of an outbreak of measles in a low incidence population in Australia.

BACKGROUND Prompt and accurate laboratory diagnosis of measles is essential for case detection, outbreak management and ongoing surveillance in low incidence countries. Several disease markers are employed for diagnosis and are important to determine epidemiological and molecular characteristics for future control measures. OBJECTIVES To report different disease markers, genotypes and epidemiology of a measles outbreak in Australia, a low incidence country. STUDY DESIGN A retrospective descriptive study of the clinical and epidemiological features and laboratory diagnosis in 16 confirmed measles cases using measles serum IgM/IgG, antigen detection (IFA), viral RNA detection by real-time PCR and genotyping results for respiratory and urine specimens processed in one reference laboratory. RESULTS Of the 16 confirmed measles cases, 11 were young adults aged between 20-35 years and 15 were not age-appropriately vaccinated. The most common genotype detected was D9 (11/16), followed by D4 (1/16) and D8 (1/16). Two imported cases were from the Philippines (D4) and Italy (D9). Of six disease markers, respiratory swab PCR and serum IgM gave the highest percentage (100%) of positive samples for confirmed cases followed by urine PCR (90.9%), serum PCR (66.6%), urine IFA (54.5%) and respiratory IFA (46.2%). CONCLUSIONS Measles should be considered in the differential diagnosis of a presentation with fever and rash, even in countries in the elimination phase of measles control. Genotyping is a powerful molecular-epidemiological tool to assist low incidence countries towards eradication goals. Improving vaccination coverage remains essential, particularly in young adults and travellers.

Proficiency of Nucleic Acid Tests for Avian Influenza Viruses, Australasia

An avian influenza quality assurance program was used to provide information for laboratories on the sensitivity and specificity of their avian influenza nucleic acid testing. Most laboratories were able to correctly detect clinically relevant amounts of influenza virus (H5N1), and results improved as each subsequent panel was tested.

Global Resources and Eco-Labels: A Neutrality Result

I evaluate the effectiveness of eco-labeling programs that are designed to mitigate transboundary environmental problems. A simple two-country model is considered, where consumers in each country value a common environmental resource. It is shown that, in equilibrium, the level of damage is independent of whether one or both countries have eco-labeling policies. Hence, the implementation of an existing eco-labeling program by a second country may have no effect, or a very limited effect, on the stock of the environmental resource. The result highlights potential limitations of eco-labeling policies in this international context.