Diagnosis of and screening for cytomegalovirus infection in pregnant women.

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: < or =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.

Acute hepatitis C virus infection in an Australian prison inmate: tattooing as a possible transmission route.

Clinically apparent hepatitis C virus (HCV) infection developed in a prison inmate after two tattooing episodes within the recognised incubation period for HCV infection. Seroconversion and HCV viraemia with subsequent resolution of hepatitis and loss of plasma viraemia were documented. Introducing licensed tattooists, and thereby improving infection control practices, may reduce the risk of hepatitis C virus infection in prisons.

Hepatitis C prevalence among Australian injecting drug users in the 1970s and profiles of virus genotypes in the 1970s and 1990s.

OBJECTIVES: To examine the seroprevalence of hepatitis C virus (HCV) in the Australian injecting drug-using community in the 1970s, and to compare the profile of HCV genotypes with that seen in the 1990s. DESIGN: Investigation of stored sera that were collected from injecting drug users in the 1970s and comparison with sera collected in the 1990s. SETTING: Inner Sydney, 1974-1975 and 1994-1996. PATIENTS: The 1970s group comprised 141 consecutive injecting drug users who attended the Brisbane Street Methadone Clinic. The 1990s group comprised 88 consecutive, injecting drug users of European origin who were HCV antibody-positive and attended a primary healthcare facility (the Kirketon Road Centre). MAIN OUTCOME MEASURES: HCV antibody prevalence (1970s); profile of HCV serotypes (1970s and 1990s); and serological evidence of hepatitis A and B. RESULTS: 84% of the 1970s group were HCV antibody-positive, of whom 92% were infected with HCV serotype 1 and 1% with serotype 3. In contrast, in the 1990s group, 69% were infected with HCV serotype 1 and 25% with serotype 3. The HCV-positive subjects from the early group were more likely than those from the recent group to have serological evidence of previous HBV infection. CONCLUSIONS: The high prevalence of HCV among injecting drug users in the 1970s in Australia confirms an epidemic that has been present for at least 25 years. Over this period, the proportion of HCV genotype 1 infections has decreased and genotype 3 infections have emerged.

Difficulties in clinical diagnosis of measles: proposal for modified clinical case definition.

OBJECTIVE: To examine the accuracy of clinical diagnosis of measles and to develop an improved measles clinical case definition. DESIGN: Case survey. SETTING: Eastern Sydney, December 1990 to August 1993. SUBJECTS: All cases of measles notified to the Eastern Sydney Public Health Unit without or before serological confirmation. OUTCOME MEASURES: Demographic and clinical details, measles- and rubella-specific IgM and measles complement fixation titres in acute and convalescent (when available) sera and epidemiological links with confirmed measles cases. RESULTS: Of 49 subjects reported and with complete follow-up, 24 were confirmed with measles, four with rubella and 21 had no definite diagnosis. Clinical diagnosis of measles had a false positive rate of 51%. Subjects with confirmed measles were significantly more likely to have a cough (23/24) than those with no definite diagnosis (15/21; P = 0.03) and to be febrile on the day of rash onset (23/24 versus 10/21; P = 0.001). The Centers for Disease Control definition had a sensitivity of 92% but specificity of only 24%. A modified case definition of rash, cough and fever present at onset of rash had equal sensitivity but greater specificity (57%). CONCLUSIONS: As measles is no longer common in Australia, clinical diagnosis is unreliable. When a public health response is needed, cases should be confirmed by serological tests or, if not available, we propose use of our modified clinical case definition.

Cost effectiveness of prevaccination screening of health care workers for immunity to measles, rubella and mumps.

OBJECTIVES: To determine the value of infection and vaccination histories as predictors of immunity to measles, rubella and mumps, and to compare the costs of various screening strategies with the cost of universal vaccination of health care workers. SETTING: Staff employed by a Sydney children's hospital. METHODS: Histories of measles, rubella and mumps infection or vaccination were compared with the results of serological testing to determine which historical statements had high positive predictive values (PPV) for immunity. Using this, we devised three prevaccination screening strategies and compared their costs with the cost of universal staff vaccination. RESULTS: Of 235 participants, 98.3% were serologically immune to measles, 96.6% to rubella and 83.0% to mumps. Historical statements indicating immunity with a PPV of more than 95% were histories of measles or of rubella vaccination, and personal recollection of mumps infection. Strategies using historical screening were cheaper than universal vaccination, which in turn was cheaper than using serological screening alone. CONCLUSIONS: Among health care workers at occupational risk of measles, rubella and mumps, the need for vaccination can be reduced by combining historical and serological screening. Where screening is felt to impose an administrative burden, a universal vaccination strategy costs 30%-50% more than strategies which use historical screening.

Bordetella pertussis infection: a cause of persistent cough in adults.

An enzyme-linked immunosorbent assay (ELISA) for Bordetella pertussis-specific immunoglobulin (Ig)A antibody in serum was used to demonstrate B. pertussis infection. The upper limit of normal for the assay (mean + 3 SD) was established by testing sera that had been collected from a group of healthy blood donors. All 13 patients with clinical whooping cough from whom B. pertussis was isolated and 25.7% of 218 adults, who were aged 18-81 years, who were referred to a consultant physician for the investigation of a persistent cough, had elevated levels of IgA to B. pertussis. The study confirms the B. pertussis IgA ELISA as a sensitive test for the diagnosis of B. pertussis infections and that these infections cause respiratory illness, in particular, persistent cough in adults.