Hepatitis B immunisation coverage of infants born to chronic carrier mothers in Victoria

Infants born to HBsAg- (hepatitis B surface antigen) carrier mothers are highly likely to become chronic hepatitis B (HB) carriers themselves unless their status is recognised at birth and they are immunised with three doses of HB vaccine, the first within 48 hours of birth, concurrent with hepatitis B immune globulin (HBIG). This study was designed to determine how many infants born in Victoria to carrier mothers completed three doses of HB vaccine. We sent the names of all infants of HBsAg-carrier mothers notified in Victoria between 1.7.91 and 30.6.92 to the appropriate local government immunisation providers and requested information on how many doses of HB vaccine, DTP (diphtheria-tetanus-pertussis) or CDT (combined diphtheria-tetanus), and OPV (oral polio vaccine) they had received. The HBsAg-carrier prevalence of women giving birth in Victoria in 1991-92 was at least 0.52%. Of the 336 infants notified, 239 (71.1%) were recorded in local government records. Of these 239, 90.8% received at least two doses and 80.8% received at least three doses of hepatitis B vaccine. There was no significant difference in the number who received three doses of HB vaccine compared with three doses of DTP or CDT vaccine. Of the entire cohort of 336, only 57.4% were documented as being completely immunised against hepatitis B. HB immunisation coverage for these infants needs to be improved. The high rate of loss to follow-up, especially between the maternity hospital and the community, is disturbing. Mechanisms for intensive prospective follow-up of these infants should be developed to prevent loss to follow-up and to encourage full immunisation against HB. Improving HB immunisation coverage of infants in high HBsAg-prevalence ethnic groups and introduction of universal infant HB immunisation may lead to increased coverage of infants of carriers by serving as back-up mechanisms for those lost to follow-up.

[Enteroparasitoses in food handlers of the public schools in Uberlândia (Minas Gerais), Brazil]

A prospective study based on a parasitologic survey was carried out with a view toward controlling enteroparasitoses in food handlers who work in public primary schools in Uberlândia, Minas Gerais, Brazil. The study subjects were 264 individuals from 57 schools, from whom three fecal samples (C) were collected: C1 in September 1989, C2 in April 1990, and C3 in September 1990. The participants were predominantly female (259 women and 5 men) and ranged in age from 20 to 66 years. A total of 792 samples were preserved in 10% formalin and analyzed using the method of Hoffman, Pons, and Janer. Intestinal parasites were found in 17%, 10%, and 10% of the C1, C2, and C3 samples, respectively. The following organisms were found in C1: Giardia lamblia (8%), ancylostomids (6%), Ascaris lumbricoides (3%), Entamoeba histolytica (2%), Strongyloides stercoralis, Hymenolepis nana, Taenia sp., and Trichuris trichiura (less than 1% each). Parasites found in C2 were: ancylostomids (5%), G. lamblia (2%), A. lumbricoides (1%), S. stercoralis, H. nana, Taenia sp., and Enterobius vermicularis (less than 1% each). In C3, the parasites observed were: ancylostomids (5%), G. lamblia (3%), A. lumbricoides (2%), S. stercoralis, and E. vermicularis (less than 1% each). After each collection, the individuals found to be infected received specific treatment. The authors recommend the establishment of epidemiologic surveillance through periodic parasitologic exams, specific treatment, and training on hygienic food handling and personal hygiene for all food handlers.

Group B streptococcus: maternal carriage rate and early neonatal septicaemia

Between January 1984 and December 1994, 30 cases of early neonatal group B streptococcus (GBS) septicaemia were managed in the Neonatal Unit, University Hospital, Kuala Lumpur. Two neonates were outborn and 28 were inborn, giving an average annual incidence of neonatal GBS septicaemia of 0.4/1000 livebirths among inborn babies. In a separate survey over a three-month period, GBS genital carriage rate among 196 parturients was found to be 9.7%. Of the infants with GBS septicaemia, the mean gestational age was 37.5 +/- 3.8 weeks and the mean birthweight was 2540 +/- 716 g. Twelve (40%) were preterm infants and 14 (47%) were low birthweight infants. Male and female infants were almost equally affected. Prolonged rupture of membranes and maternal pyrexia accounted for only 5 (17%) and 3 (10%) of the cases respectively. Twenty-four (80%) neonates had onset of symptoms within 6 hours of life and respiratory symptoms were observed in 24 (80%) of the cases, while meningitis was uncommon. Six (20%) neonates died. Preterm and low birthweight infants had higher mortality than their term counterparts: 42% versus 6% and 36% versus 6% respectively. Of those who died, 4 (67%) required respiratory support right from birth and the mean time of onset of symptoms was 4 hours (range 0 to 21 hours) and the duration of survival was only 28.8 hours (range 12 to 38 hours). As the incidence of neonatal GBS septicaemia was low, mass screening and chemoprophylaxis for GBS were not recommended. All the GBS isolates were sensitive to penicillin and ampicillin, thus one of these antibiotics should be included in the antimicrobial therapy of septic neonates.

[Transmission routes of hepatitis C virus in carrier patients and study of family contacts]

A study was made of the routes of transmission of HCV in 106 carrier patients and the prevalence of antibodies to HCV antigen (HCV Ab) in 132 family contacts (mothers, sexual partners and children of carrier women) attended at a Primary Care Center in Madrid. The following data were obtained through a personal interview: age, gender and possible routes of contagion. Also, ALT and serologic status to HBV. Household contacts were interviewed and HCV Ab status obtained. Only in 21 patients (19.8%) was no risk factor found ("sporadic cases"). Eighty-one individuals (76.4%) and 13 (12.3%) had percutaneous transmission and sexual transmission risk factors, respectively. Out of 18 studied mothers, two (11.1%) had HCV Ab. The prevalence of HCV Ab in household contacts was 8.35%. These results suggest that the proportion of sporadic cases decreases significantly when a thorough investigation is carried out in carrier patients. The percutaneous route is responsible for most of HCV infections. The prevalence of HCV Ab among household contacts appears to be higher than among general population.

[Frequency of hepatitis GB virus C in patients on maintenance hemodialysis]

Hepatitis GB virus C(HGBV-C) RNA was detected in 10(4.5%), among the 223 patients on maintenance hemodialysis. Of the 10 patients with HGBV-C RNA, 4(40%) were also infected with HCV. All patients with HGBV-C RNA had a history of blood transfusion. HGBV-C is suspected to be transmitted by blood transfusion. And also, none of the 10 HGBV-C RNA positive-patients had evidence of liver dysfunction. All patients are asymptomatic HGBV-C carrier. The patients on maintenance hemodialysis are high risk group for HGBV-C infection.

[The epizootic characteristics of tularemia in the Crimea]

Cases of tularemia were registered in the Crimea both before and after planned immunization. In 1981-1993 in 4.000 localities 35,100 mammals, 27,400 ectoparasites, 8,800 feces left by birds of prey and foxes and 900 environmental specimens were studied. 137 Francisella tularensis strains were isolated. Field mapping of the spread of F.tularensis and places of habitation of small mammals was carried out. The active polyhostal natural focus of tularemia was found to exist on the Kerch Peninsula, less affected by anthropogenic factors, where tularemia morbidity among humans, and tularemia epizootic coincided with the maximum rises in the number of myomorphs. The core of the focus constituted 2.4% of its area and were characterized by the stable complex of Ixodes ticks and the preservation of F. tularensis in the environment. In other regions of the flat part of the Crimea with considerable anthropogenic transformations of the landscape rises in tularemia epizootics and tularemia morbidity in humans were rare. In the mountainous part of the Crimea tularemia epizootics were registered only by the detection of specific antibodies and antigens.

[Salmonella infection in a large general hospital]

In this work the results of the epidemiological survey of the epidemic of salmonellosis in a large hospital with diversified specialization are given. The detailed description of morbidity dynamics with the distribution of the described cases according to the severity of the course of the infectious process, the groups of the most affected patients and the mechanism of the transmission of infection under hospital conditions is presented. This epidemic of salmonellosis is considered from the viewpoint of the theory of the self-regulation of parasitic systems. The characteristic features of nosocomial salmonellosis, detected in the course of the epidemiological survey, make it possible to determine the main trends in the prophylaxis of this infection in a large hospital.

Risk factors for Neisseria meningitidis carriage in a school during a community outbreak of meningococcal infection

As part of the management of an outbreak of meningococcal infection, 119 school contacts of an index case were swabbed for nasopharyngeal carriage. In a cohort study, risk factors for Neisseria meningitidis carriage were ascertained by means of a questionnaire, completed by 114 (96%) of those swabbed. Twenty five (21%) cultures were identified as "neisseria positive'; of which there were 18 (15%) Neisseria meningitidis isolates, 2 (2%) Neisseria lactamica isolates and 5 (4%) showed contaminants only. Two (2%) carriers were identified as harbouring the implicated outbreak strain. Single variable analysis identified six statistically significant risk factors for meningococcal carriage; increasing age, female sex, manual social class, personal smoking, regular attendance at a discotheque and rhinorrhoea. Multivariate analysis, using logistic regression modelling, found that of these six variables only age, sex and social class remained statistically significant when the other factors were controlled for. Nevertheless the role of smoking, social events and respiratory/viral infections in nasopharyngeal carriage, and other plausible mechanisms whereby age, sex and social class might exert their effect, could usefully be investigated further.

Epidemiological patterns of hepatitis B virus (HBV) in highly endemic areas

This paper uses meta-analysis of published data and a deterministic mathematical model of hepatitis B virus (HBV) transmission to describe the patterns of HBV infection in high endemicity areas. We describe the association between the prevalence of carriers and a simple measure of the rate of infection, the age at which half the population have been infected (A50), and assess the contribution of horizontal and perinatal transmission to this association. We found that the two main hyper-endemic areas of sub-Saharan Africa and east Asia have similar prevalences of carriers and values of A50, and that there is a negative nonlinear relationship between A50 and the prevalence of carriers in high endemicity areas (Spearman's Rank, P = 0.0086). We quantified the risk of perinatal transmission and the age-dependent of infection to allow a comparison between the main hyper-endemic areas. East Asia was found to have higher prevalences of HBeAg positive mothers and a greater risk of perinatal transmission from HBeAg positive mothers than sub-Saharan Africa, though the differences were not statistically significant. However, the two areas have similar magnitudes and age-dependent rates of horizontal transmission. Results of a simple compartmental model suggest that similar rates of horizontal transmission are sufficient to generate the similar patterns between A50 and the prevalences of carriers. Interrupting horizontal transmission by mass immunization is expected to have a significant, nonlinear impact on the rate of acquisition of new carriers.

[Basic and clinical aspects of hepatitis virus carriers]

Among the six species of hepatitis viruses, HBV (hepatitis B virus) and HCV (hepatitis C virus) can induce persistent infection. HBV and HCV are transmitted parenterally, of which maternal transmission and transfusion-associated infection is a major route respectively. We opened the special clinic for carriers detected through blood donation, and followed them at regular intervals for their health care. The prevalence rate of HBV carriers decreased from 3.0% to 1.2% in these 10 years, and that of HCV decreased from 0.9 to 0.4% in these 4 years. Prevalence rate of HBV peaks at 50s and that of HCV peaks at 60s. Due to nearly complete screening of donated blood, post-transfusion hepatitis almost disappeared. HBV vaccine for neonates born from infected mothers reduced the new incidence of HBV carriers. In HBV carriers seroconversion of HBeAg to HBeAb occurs at teens with transient hepatitis and appearance of mutant virus. Ninety percent of the carriers remains healthy for the lifetime but some of them aggravate into chronic hepatitis leading to HCC (hepatocellular carcinoma). In HCV acute infection at adult age succeeds to chronic infection and eventually to liver cirrhosis with sporadic appearance of HCC. On the other hand, less than 50% of HCV carriers seem to be asymptomatic and do not lead to grave disease. In HBV carriers tendency to reject the virus occurs and eventually HBV is cleared in some percentage of the population. In contrast HCV does not tend to be cleared. HBsAb is a defensive antibody. In contrast HCVAb is not a defensive antibody but an infective antibody like HBcAb. DNA polymerase is a good marker of disease state in HBV, and HCV RNA is a good marker of HCV proliferation. Treatment with IFN is sometimes effective for seroconversion in HBV, and for eradication of virus in HCV.

[Familial transmission of hepatitis C virus]

OBJECTIVE

To establish the prevalence of antibodies to hepatitis C virus (HCV) among relatives and other persons cohabiting with HCV carriers, as an indication of the risk of intradomestic transmission.

EXPERIMENTAL DESIGN

A transversal study of series of clinical cases. A questionnaire was applied to the index cases (IC) and contact cases (CC), differentiating sexual contacts (SC) from non sexual contacts (NSC).

PATIENTS

One hundred and sixty four IC and 533 CC were included. Information on parenteral risk factors, type of sexual relationship, period of exposure, and other epidemiological variables was obtained. Antibodies to HCV (HCV-Ab) were determined by 2nd generation ELISA.

RESULTS

In eighty eight IC (53.6%) no parenteral risk factors were found. In 99 IC (62.8%) a liver biopsy showed chronic hepatitis or cirrhosis. Twelve CC (2.25%) turned out to be HCV-Ab (+), a ratio above that found in our city (0.3%, p < 0.001), however the comparison should be taken with caution. No significant differences were found with respect to several epidemiological variables, including type of sexual relationship, and socioeconomic indicators, between CC HCV-Ab (+) and (-). Stage of liver disease in the IC and relationship between IC and CC did not increase the risk of being HCV-Ab positive. In HCVAb positive CC a higher proportion of parenteral risk factors (p < 0.001), elevated ALT (p < 0.001) and sharing of personal tools (p < 0.01) were observed.

CONCLUSIONS

Intrafamiliar transmission of HCV is poorly documented and it is related to the presence of parenteral risk factors. The actual prevalence of HCVAb in a general population is unknown, rendering difficult to make definite conclusions.

[The risk factors for hepatitis D viral infection in southern Italy]

The aims of this study were to evaluate the prevalence of hepatitis delta virus (HDV) infection and risk factors associated to it. Three hundred sixty-one HBsAg chronic carriers from southern Italy were studied and 13.8% of them resulted anti-delta positive. 80% of these subjects were less than 50 years old. When anti-delta positive subjects were compared with anti-delta negative ones, a lower number of healthy HDV carriers and a higher frequency of cirrhotics were noted among anti-delta positive. Of lower than 50 years, imprisonment, sexual contacts with drug abusers and male homosexuality were risk factors of HDV infection. No association was found with sex, household contacts with HBV or HDV carriers, number of family members and transfusion of blood products. These data confirm the high prevalence of HDV infection in southern Italy.

[Screening of Streptococcus agalactiae (group B) in the perinatal period]

OBJECTIVE

To determine the carriage rate of Streptococcus agalactiae in a group of pregnant women and evaluate its role in a neonatal infections.

DESIGN

Prospective study between December 1992 and May 1993.

SETTING

University hospital.

PARTICIPANTS

166 patients aged 17 to 41 years (m = 28 yrs) with a gestational age of 32 to 42 wks (m = 39.99 +/- 1.73) were admitted to the delivery suite. All patients had a vaginal swab on admission before any lavage.

RESULTS

The recovery rate of Streptococcus agalactiae (group B) was found to be 7.8% (13/166) in our population. Twelve of the thirteen newborn to colonized mothers (92%) were term newborn as compared to 141 of 153 (92.1%) newborn to non-colonized mothers (p = 0.72). Three of thirteen (23%) colonized mothers had premature rupture of membranes and 23% (3/13) had prolonged labor > 12 h as compared to of 38 (25.1%) and 8 (5.1%) non-colonized mothers (respectively p = 0.58; NS; p = 0.035). No intra-partum fever was reported. All neonates born to colonized mothers had a birth weight > 2,800 g, an average Apgar score of 8.6 while neonates of non-colonized women had a weight > 2,800 g in 89.4% of cases and an average Apgar of 8.8 (p = 0.9). Two (15.4%) newborn infants born to colonized mothers had an early neonatal infection: one had a pneumonia and had a favorable outcome, the other one developed sepsis and meningitis and died on day 3.

CONCLUSION

Despite the low rate of Streptococcus agalactiae (group B) colonization (found in our population), regular identification of the organism is recommended because of the high risk of neonatal infection with a high mortality. Further studies on a larger group are needed to confirm such an approach.

Continuing risk for hepatitis B virus transmission among Southeast Asian infants in Louisiana

OBJECTIVE

Implementation and evaluation of a hepatitis B vaccination program for Southeast Asian infants in Louisiana.

METHODS

A baseline seroprevalence survey of hepatitis B virus (HBV) infection in US-born Southeast Asian children was conducted in 1991 before the implementation of a vaccination program. Hepatitis B vaccination and postvaccination serologic testing of survey participants 10 years of age and younger was performed. Eighteen months after the hepatitis B vaccine was integrated into infant immunization schedules in July 1993, a vaccination coverage survey was performed.

RESULTS

Baseline serologic testing was conducted on 96% of persons from 225 randomly selected households in a Southeast Asian community in Louisiana. Of 676 US-born children, 28 (4.1%) had chronic HBV infection; 61% of children with chronic HBV infection were born to hepatitis B surface antigen (HBsAg)-negative women. Among children born to HBsAg-negative women, the prevalence of chronic HBV infection increased with age, reaching 7.3% for children 13 to 16 years of age. Children born to HBsAg-negative women and living with carriers were 5.4 times more likely to have evidence of HBV infection than were children who did not live with carriers. Before the survey, only one child had received three doses of hepatitis B vaccine. In July 1993, 43% of Southeast Asian infants 9 to 18 months of age born in Louisiana had received three doses of hepatitis B vaccine. Infants who received immunizations from private providers were more likely to be fully vaccinated than were infants who received services from public sector clinics (prevalence ratio, 2.1; 95% confidence interval, 1.4, 3.1).

CONCLUSIONS

HBV transmission occurs throughout childhood in US-born Southeast Asian children, and the prevalence of chronic HBV infection approaches that of the country of origin. Few US-born Southeast Asian children have received hepatitis B vaccine. Because of the high rates of early childhood HBV transmission and the high risk of chronic infection in Asian and Pacific Islander communities, prevention efforts should be enhanced to ensure that all Asian and Pacific Islander infants receive hepatitis B vaccine in the first 12 months of life and that older children are vaccinated.