MMR vaccination, measles epidemiology and sero-surveillance in the Republic of Ireland.

OBJECTIVE: Following the introduction of a national measles and subsequent MMR vaccination programme, to determine the susceptibility of 3-14-year-old children to measles, mumps and rubella and to relate the results to the epidemiology of measles and the need for vaccination policy changes. DESIGN: Cross-sectional sero-survey and trends in measles notifications and mortality. SETTING: Paediatric hospital outpatient departments in Dublin. SUBJECTS: Sera were collected from 837 children attending the clinics in 1991 and 1992. RESULTS: The prevalence of antibodies in children aged 3-6, 7-10 and 11-14 years was 84, 83 and 95% for measles; 48, 60 and 65% for mumps; and 78, 63 and 74% for rubella, respectively. The prevalence of mumps antibodies may be underestimated. Ninety-six per cent of girls aged 13-14 years had rubella antibodies. A widespread outbreak of measles occurred in 1993. Over recent years, an increasing proportion of measles notifications were in older children. CONCLUSION: Given sub-optimal uptake of MMR vaccine, outbreaks of infection in pre- and primary school children are inevitable. In such circumstances, a 2-shot MMR vaccine programme with high uptake is essential to prevent a shift of disease into older age groups.

Epidemiology of respiratory syncytial virus infection among infants over three winter seasons.

A study involving respiratory syncytial virus was carried out on infants and young children hospitalised with acute respiratory tract infection over the period December 1987 to March 1990. During peak periods of RS virus activity 420 naso-pharyngeal aspirates were submitted to the Virus Reference Laboratory, Department of Medical Microbiology, U.C.D., mostly from the Dublin region. Using immunofluorescence, enzyme linked immunosorbent assay and cell culture techniques 206 samples (49%) were identified as positive for RS virus. Over the period of study RS virus seasonal activity was confined to the winter months October to March with peaks of activity occurring during March 1988, December 1988 and January 1990. Bronchiolitis was the most common clinical manifestation of infection accounting for 48% of the total number of positive results. Eighty two point five per cent of positive detections were reported from infants less than or equal to 6 months old and particularly from infants in the 1-2 month old age group. More males than females were found to be affected by RS virus infection.

Changes in incidence of hepatitis B in Ireland from 1970-1987.

This paper analyses data on 2,226 cases of Hepatitis B virus (HBV) infection detected during the years 1970 to 1987. Of those where information on risk-group was available (1,301), infection among intravenous drug-abusers accounted for the largest proportion (49%). Most became infected during and since an outbreak of hepatitis B and Delta hepatitis which originated in this group in 1980. A comparison of the data before and after the start of the outbreak among drug-abusers shows a marked increase in the number of HBV infections in non drug users, including haemophiliacs, homosexuals and health-care staff, and a dramatic decrease in hepatitis B following blood transfusion. A larger group (165 cases), many of whom are long-term healthy hepatitis B surface antigen carriers, were patients in institutions for the mentally handicapped (IMH). Most were detected recently during pre-vaccination sampling programmes. Others affected included visitors to and from high-incidence areas, tattooed persons, dialysis patients, persons born to infected mothers, and members of the security forces dealing with drug-abusers. In all, 8.4% of the hepatitis B cases detected were found to be carriers and 67% of these remained carriers in 1987 The mean duration of carriage was 3.25 years. Intravenous drug-abusers and IMH patients constituted the two largest groups of carriers. The running-three-yearly mean incidence of new cases of hepatitis B has levelled off below the peak of 1981. Although the number of cases among drug-abusers has apparently decreased, the number of cases among non drug-abusing groups has increased by 50%. (ABSTRACT TRUNCATED AT 250 WORDS)

Improved method for isolation and growth of Chlamydia trachomatis in McCoy cells treated with cycloheximide using polyethylene glycol.

The sensitivity of non-replicating McCoy cells pretreated with polyethylene glycol for the isolation of Chlamydia trachomatis from clinical specimens and for the growth of a laboratory strain was compared with the sensitivity of untreated non-replicating cell cultures. The concentration of polyethylene glycol in different solutions and the time of addition to the cell culture medium were critical. A concentration of 35% polyethylene glycol in barbitone added to the cell culture growth medium either immediately before or immediately after infection with chlamydia increased the number of inclusions detected. The rate of isolation obtained from clinical specimens was also increased when cell cultures treated with polyethylene glycol were used.

Quantitative and qualitative detection of cytomegalovirus-specific antibodies using two types of enzyme-linked immunosorbent assay.

An indirect ELISA and an inhibition ELISA were developed for the detection of cytomegalovirus (CMV)-specific immunoglobulin G (IgG) and CMV-specific total immunoglobulin, respectively. Both assays were more specific than the complement fixation (CF) test, and titres of positive sera were 660 times higher by IgG ELISA and 6 times higher by inhibition ELISA than titres by the CF test. Titres by IgG ELISA were reliably determined using the absorbance obtained at a single serum dilution of 1/1,000 in conjunction with a standard graph. Both ELISAs compared favourably with each other in sensitivity and specificity in determining CMV immune status. The inhibition ELISA, in particular, provides a simple and reliable method of screening sera, which requires no control antigen or predilution of sera. It should prove useful for large-scale screening procedures, such as blood donor testing.

Increased severity and morbidity of acute hepatitis in drug abusers with simultaneously acquired hepatitis B and hepatitis D virus infections.

Hepatitis D virus (delta agent) markers were present in 111 (36%) of 308 intravenous drug abusers who were positive for hepatitis B surface antigen (HBsAg), 52 of these having hepatitis D virus antigenaemia. IgM antibody to hepatitis B core antigen (anti-HBc IgM) was present in 92 out of 95 subjects tested, indicating that hepatitis D virus and hepatitis B virus infections had been acquired simultaneously. Hepatitis D virus markers were present in three out of four patients with fulminant hepatitis, and in 80 of 223 (36%) with mild or moderate hepatitis compared with four of 29 (14%) of those who were asymptomatic. These proportional differences were significant (p less than 0.001). Hepatitis D virus markers were present in twice as many patients positive for anti-HBc IgM requiring admission to hospital with acute hepatitis compared with outpatients attending a drug treatment centre. Tests on one patient showed complete disappearance of HBsAg, but hepatitis D antigen (HDAg or delta antigen) and hepatitis B e antigen (HBeAg) were still present in serum samples. All five patients with chronic active hepatitis had hepatitis D antibody (anti-HD) compared with seven of 24 (29%) with chronic persistent hepatitis (p = 0.008). Blocking anti-HD persisted for long periods after simultaneous infections with hepatitis B virus and hepatitis D virus but at lower titres than in patients with chronic liver disease.

Persistence of rubella antibodies 15 years after subcutaneous administration of Wistar 27/3 strain live attenuated rubella virus vaccine.

The rubella-specific antibody levels of children vaccinated with RA 27/3 rubella vaccine have been determined over the 15 years since vaccination. Over the period monitored, titres have declined at a comparable rate to those observed in children who had experienced natural rubella infection. In both cohorts the mean rate of decay was similar throughout the 15 years of the study. One in eleven vaccinated children monitored for the entire period of the study reverted to a state of susceptibility to rubella as judged by routine rubella antibody tests used in practice today. The implications of the findings for rubella prophylaxis are discussed.

Detection of Chlamydia trachomatis inclusions in McCoy and HeLa-229 cells: an alternative staining technique using toluidine blue.

Toluidine blue staining was used to detect Chlamydia trachomatis inclusions in both McCoy and HeLa-229 cells from clinical specimens. This method was more sensitive than iodine staining for detecting C trachomatis inclusions in both McCoy and HeLa-229 cells and also more sensitive than Giemsa staining for detecting chlamydial inclusions in HeLa-229 cells. While its sensitivity for detection of chlamydial inclusions in McCoy cells is equal to that of Giemsa staining, toluidine blue staining is easier and faster to perform.

Acyclovir in herpes keratitis.

Herpes simplex keratitis accounts for 50 percent of patients presenting at our corneal clinic. Studies of the use of acyclovir in dendritic and geographic ulceration and disciform keratitis are presented. In a double-blind study of acyclovir and idoxuridine in 60 patients with dendritic keratitis, acyclovir was shown to be superior and produced no serious side effects. Patients with geographic ulcers have been treated on an open basis with acyclovir and the drug was found to be effective. A combination of acyclovir and dilute steroid drops appeared to be as effective as currently available treatments in the management of disciform keratitis. Double-blind studies are now in progress to evaluate acyclovir in geographic and disciform keratitis.

Randomised double-blind trial of acyclovir and idoxuridine in dendritic corneal ulceration.

The results of a randomised double-blind clinical trial of 3% acyclovir and 0.5% idoxuridine (IDU) ophthalmic ointments in 60 patients with corneal dendritic ulceration are presented. Ulcers in all 30 patients treated with acyclovir healed compared with 22 (76%) of 29 patients treated with IDU (P < 0.01). Patients treated with acyclovir healed more rapidly (average 4.4 days) than those who received IDU (average 9.2 days) (P < 0.01). No serious side effects were observed, though transient stinging was recorded in 8 patients receiving acyclovir and in 2 patients receiving IDU. Other side effects in the IDU treated group were watering in 2 patients and superficial punctate erosions in 6 patients.