The risk of hepatitis B transmission from health care workers to patients in a hospital setting--a prospective study

A prospective study was designed to determine the risk of hepatitis B transmission from health care deliverers to patients in the hospital setting. Six chronic carriers of hepatitis B were identified: 2 surgeons, 1 dialysis nurse, 1 pediatric ICU nurse, 1 pharmacist and 1 orderly. Three of the six were HBeAg-positive. Two of the HBeAG-positive chronic carriers also had circulating hepatitis B virus DNA and accounted for approximately two-thirds of the total patient contacts. Two hundred thirteen patients were exposed 450 times to these six hepatitis B carrier staff without evidence of hepatitis B acquisition over a 6-month follow up. One-hundred nineteen control patients, exposed 789 times to noncarrier health care deliverers, were also negative. Another 33 patients were exposed to three additional individuals who were in the prodrome of acute hepatitis B: an intensive care nurse, a dental hygienist and a medical student. These patients showed no evidence of hepatitis B during 6 months of follow-up, nor did 25 separate control patients. Thus, 246 patients were exposed a total of 483 times to nine health care personnel who had either acute or chronic hepatitis B. No evidence of hepatitis B transmission was found. One-hundred forty-four controls revealed similar results after 814 exposures. Based on the number of exposures to chronic carriers alone, the risk of hepatitis B transmission is estimated to be less than 1%.(ABSTRACT TRUNCATED AT 250 WORDS)

[Characteristics of the sources and routes of spread of a Pseudomonas aeruginosa infection in a trauma department]

In the study of the epidemic process of P. aeruginosa infection in a traumatological hospital the leading role of patients with hospital septic infections as the sources of infection has been epidemiologically proved. Contamination has been shown to occur mostly in the pus dressing room.

Perinatal transmission of hepatitis B virus in Thailand

Perinatal transmission of hepatitis B virus (HBV) from asymptomatic HBsAg carrier mothers to their infants was studied in 78 mother-infant pairs by determination of HBsAg, HBeAg and anti-HBe both in the mothers and in their infants at regular intervals for those children up to the time when they reached at least one year of age. Twenty-five out of the 78 (32.1%) infants born to these mothers were HBsAg-positive 2-6 months after birth and they remained so throughout the observation period of at least one year or more. Perinatal HBV transmission occurred only in infants born to HBsAg carrier mothers who were HBeAg-positive (92.6%) but not in those born to HBsAg carrier mothers who had no detectable HBeAg. This study suggests that preventive measures against HBV transmission during the perinatal period should be taken only for infants born to HBsAg carrier mothers who are HBeAg-positive. In addition, the active immune response to HBV was studied in 75 non-HBsAg carrier infants born to HBsAg carrier mothers by determination of anti-HBs at one year of age or older. Forty-three of these infants were treated with HBIG at birth and 32 infants received no treatment. It was found that infants born to HBsAg carrier mothers who were HBeAg-positive had a better active immune response (84.2% positive for anti-HBs) than infants born to HBsAg carrier mothers who had no detectable HBeAg or anti-HBe (14.3% and 20.4% positive for anti-HBs respectively).

Perinatal hepatitis B virus transmission in the United States. Prevention by passive-active immunization

Among infants born to women in whom sera are positive for both the hepatitis B surface antigen and the e antigen, 85% to 90% are infected with hepatitis B virus and become chronic hepatitis B surface antigen carriers. In a study to assess the effectiveness of passive-active prophylaxis (hepatitis B immune globulin and hepatitis B vaccine) of such infants, we screened 18,842 pregnant Asian-American women: 8.7% were positive for hepatitis B surface antigen and 3.0% were also positive for hepatitis B e antigen. Thus far, 113 infants have received hepatitis B immune globulin (0.5 mL at birth) and hepatitis B vaccine (three 20-micrograms doses beginning at birth or at 1 month) and have been followed up for nine to 18 months. Among these infants, 16 have become chronic carriers, an incidence of only 14.2%. All of the uninfected infants have retained high levels of antibody to surface antigen, suggesting that they have had an active immune response to the vaccine and should have long-term protection against hepatitis B virus.

Maternal-child hepatitis B virus transmission in Singapore

A study of maternal-infant transmission of hepatitis B virus (HBV) was conducted in Singapore between June 1980 and June 1982. HBsAg carrier rate was highest among Chinese (6.2%) followed by Malay (2.3%) and Indian (0.6%) mothers. The presence of HBeAg in maternal sera correlated well with high titre HBsAg (p = 7.34 X 10(-5)). Overall HBV transmission occurred in 27/56 (48.2%) infants from carrier mothers. The majority of the transmission was perinatal. There was a very strong correlation between transmission and HBeAg status of the mother (p = 1.85 X 10(-9); odds ratio = 68.44) and to a lesser extent with high titre HBsAg (p = 0.002; odds ratio = 6.38). A strong negative correlation was seen between transmission and anti-HBeAg (p = 8.19 X 10(-7); odds ratio = 0.04). At one year 19 (70.4%) infants were still HBsAg positive while seven (25.9%) lost the antigenemia and acquired anti-HBsAg and one developed HBsAg after one year. It could be calculated that perinatal HBV transmission contributed about 18% to the total pool of HBsAg positive infants of one year of age.

Mothers of infants with the acquired immunodeficiency syndrome. Evidence for both symptomatic and asymptomatic carriers

Sixteen mothers of 22 infants with the acquired immunodeficiency syndrome (AIDS) or AIDS-related complex were followed up for evidence of clinical and immunologic abnormalities. With one exception, all mothers were clinically well at delivery but had evidence of immune dysfunction, with T-cell abnormalities and inverted T4/T8 ratios and/or elevation of serum immunoglobulin levels, particularly of IgG. During a follow-up period that averaged 30 months, AIDS developed in five of the mothers and AIDS-related complex in seven. Twelve subsequent pregnancies in 11 mothers produced four affected infants, suggesting that mothers can be persistently infected. Six mothers were delivered of subsequent infants who remain unaffected. These results suggest that the mothers are the likely source of infection in non-transfusion-associated cases of AIDS or AIDS-related complex in infants, that mothers have persistent immunologic abnormalities, and that they are at increased risk of developing AIDS or AIDS-related complex.

Vertical transmission of hepatitis B surface antigen in Saudi Arabia

The prevalence of hepatitis B surface antigen (HBsAg) was studied in 3020 pregnant Saudi women. All the sera of 119 (3.9%) HBsAg-positive asymptomatic carrier mothers were titrated for HBsAg and investigated for hepatitis Be antigen (e-Ag) and its antibody (anti-e-Ag). Only 13 (10.9%) of the carrier mothers were e-Ag-positive compared with 89 (74.8%) who had anti-e-Ag. There was a positive correlation between the titres of HBsAg and the presence of e-Ag. Studies on 49 mother-child pairs revealed that vertical transmission occurred from six of seven carrier mothers (85.7%) who were e-Ag positive compared with two of 32 mothers (6.25%) who were e-Ag negative but had anti-e-Ag. On the basis of these results, the low prevalence of e-Ag in asymptomatic Saudi mothers contrasts markedly with the situation in asymptomatic carrier mothers from the Orient, but its presence, as shown by other studies, is a good predictor of vertical transmission.

[Epidemiological characteristics and the importance of carriers of the surface antigen of the hepatitis B virus (HBsAg)]

The occurrence of HBsAg carriership in Leningrad has been found to be 1.4% according to the results of countercurrent immunoelectroosmophoresis (CIEO) and 2.1% according to the results of the passive hemagglutination (PHA) test. In children HBsAg occurs with higher frequency: 1.9% according to the results of CIEO and 3.4% according to the results of the PHA test. The latter test reveals HBsAg carriers more completely, especially in women who have usually less pronounced antigenemia than men. Most of chronic HBsAg carriers are patients with chronic forms of hepatitis B (chronic active hepatitis and chronic persistent hepatitis); frequently they become the source of infection among their relatives under the conditions of family contacts. A complex of antiepidemic measures is necessary in the foci of chronic HBsAg carriership.

Contact tracing in the acquired immune deficiency syndrome (AIDS). Evidence for transmission of virus and disease by an asymptomatic carrier

The sexual contacts of a patient with acquired immune deficiency syndrome were traced, and clinical, immunological, and serological evidence was obtained and evaluated. It was determined that the patient acquired the disease from a homosexual man who had no symptoms, but in whom laboratory evidence of immunodeficiency and serological evidence of exposure to the AIDS-associated retrovirus was found.

Hepatitis B as an occupational disease of surgeons

Hepatitis B is an occupational hazard of great magnitude to the practicing surgeon or surgeon-in-training. Knowledge of the basic serologic and clinical events which occur in the various forms of hepatitis B is important for effective care of patients and for understanding the personal risk involved in surgical practice. Evidence of prior infection from hepatitis B is present in more than 25 per cent of surgeons who are actively practicing. Although the risk of acquiring hepatitis as a surgeon is high (about 5 per cent per year), the majority of instances are asymptomatic. The risk to patients who are cared for by a chronically antigenemic surgeon would appear to be extremely low, and, thus, the chronic presence of surface antigen is not an indication for cessation of operating or patient care. The newly released vaccine against hepatitis is efficacious and safe, and immunization of surgeons who are seronegative is strongly recommended. Rapid progress is being made in the understanding of the transmission, treatment and prevention of type B viral hepatitis. The practicing surgeon is urged to stay informed of new developments regarding this occupational disease.

Transmission of duck hepatitis B virus from Chinese carrier ducks to Japanese ducklings: a study of viral DNA in serum and tissue

Human hepatitis B-like viruses have been found in several animal species, including Chinese ducks. Sera from Chinese carrier ducks which were positive for duck hepatitis B virus (DHBV) were inoculated in 33 Japanese one-day-old ducklings. The same sera were inoculated in four 3-week-old ducklings, and three 3-month-old ducks. Ten uninoculated ducklings served as controls. Hepatitis B e-antigen positive human sera and DNA polymerase-positive woodchuck sera were also inoculated into ducklings. DHBV was demonstrated in serum of all ducklings inoculated at one day of age and persisted for more than 6 months in 17 of 20 ducks. In the three ducks in which viremia disappeared, viral DNA was found in liver tissue. Southern hybridization revealed only free viral DNA in infected ducks. Only 1 of 7 ducklings inoculated at 3 weeks or later developed persistent infection. No cross-infectivity by hepatitis B virus or by woodchuck hepatitis virus was demonstrated. By inoculating DHBV-positive sera into 1-day-old ducklings of a virus-free Japanese flock, we were able to transmit DHBV in all of them and established a chronic carrier state in all ducks which were inoculated at 1 day of age.

Meningococcal disease and season in sub-Saharan Africa

The incidence of meningococcal disease varies seasonally in both tropical and temperate countries. This association is most apparent in sub- Saharan Africa, where almost all epidemics start in the dry season and abate during the rains . Meningococcal carriage rates do not vary with season either in Africa or in temperate countries, suggesting that seasonal factors have little influence on the frequency of meningococcal transmission. It is suggested that changes in the ratio of clinical to subclinical cases of infection are more important than changes in the frequency of transmission in producing seasonal variations in the incidence of meningococcal disease. Some evidence to support this hypothesis was obtained during an epidemic of group A meningococcal disease in northern Nigeria in 1977-79.

Hepatitis B virus carrier state in black children in Ovamboland: role of perinatal and horizontal infection

Hepatitis B surface antigen (HBsAg) was detected in 17% of adult males and 11% of mothers in Ovamboland , South West Africa/Namibia. Hepatitis B e antigen (HBeAg) was present in 15% of HBsAg-positive mothers. Only 1% of children less than 6 months of age were HBsAg-positive, compared with 13% of children over the age of 1 year. 27% of mothers who were HBsAg-positive had HBsAg-positive children, whereas the corresponding figure for mothers who were HBsAg-negative was 6%. 63% of mothers who were positive for both HBsAg and HBeAg had HBsAg-positive children. 37% of HBsAg-positive children had HBsAg-positive mothers, compared with 8% of HBsAg-negative children. Later "horizontal" rather than neonatal maternal-infant transmission of the hepatitis B virus (HBV) seems to be the more important mode of spread of this infection in Ovambo children. The difference in the pattern of transmission of this virus between the Far East and Africa seems to centre mainly on the differences in the HBeAg status of the mothers in these two regions.

[Role of carriers of the hepatitis B surface antigen as possible sources of infection in children's collectives]

The complex clinico-epidemiological and laboratory surveys of the children and the staff in 71 institutions for children of preschool age were made at the period of increased viral hepatitis morbidity in these institutions, and the dynamic observations of 11 children's institutions having children with prolonged HBs-antigenemia were carried out. In the foci of viral hepatitis the level of antigenemia in the children and the staff exceeded (p less than 0.01) that in the control group. The dynamic observations (lasting up to 6 years) of the groups containing HBsAg-carriers revealed that 6 children, previously HBsAg-negative, showed a short-term HBs-antigenemia in the absence of any evidence of the parenteral (instrumental) route of infection. This fact indicates that the role of HBsAg-carriers as the possible sources contributing to the transfer of hepatitis B through everyday contacts in children's institutions cannot be ruled out. Periodic clinico-epidemiological and laboratory surveys of groups with HBsAg-carriers are recommended.

Prevention of transmission of hepatitis B in dental practice

Hepatitis B virus (HBV) is transmitted by infected blood and possibly saliva; faecal-oral transmission is also possible. Infected material is transmitted mostly by the parenteral route. Hence, the transmission of HBV in the dental surgery should be prevented by the routine exercise of good clinical hygiene. As part of patient assessment information on recent hepatitis should be sought. Patients may carry HBV and be infectious from 1 to 4 months after contracting the disease. During this period the surface antigen (HBsAg) can be detected in blood. Symptoms generally appear from 2 to 4 months after infection. High risk groups in the community should be recognized. In communities where the disease is widespread this may include most of the population. Elective dental treatment for patients likely to be infectious should be postponed until the infectious stage has passed; this can be confirmed by showing the absence of HBsAg in blood. A high standard of clinical hygiene, including the routine use of disposable needles for injections, single dose containers for drugs to be injected, sterilized instruments and personal cleanliness before and after treating patients, is essential to prevent transmission of HBV. More stringent precautions are necessary when treating persons likely to be infectious. Although the introduction of an immunization programme to protect dentists and clinical staff is imminent proper clinical hygiene will continue to be essential to safeguard both patients and clinicians.

Materno-foetal transmission of hepatitis B in Saudi Arabia

Carriage of hepatitis B among pregnant women in Saudi Arabia and their new born infants has been studied over a period of three years. The hepatitis B surface antigen (HBsAg) carrier rate among 5000 women screened antenatally was 2 X 8 per cent. Hepatitis B subtype ayw was found more often than subtype adw. A study of 50 persistent HBsAg carriers and their newborn infants followed serologically over a period of at least two years did not reveal any evidence of materno-foetal transmission either vertically, perinatally or postnatally. Twelve per cent of mothers shown to be carrying hepatitis B 'e' antigen (HBeAg) during pregnancy did not apparently transmit the virus to their newborn infants. Materno-foetal transmission of hepatitis B virus in utero or during the perinatal period does not seem to be important in maintaining the carrier state in Saudi Arabia, horizontal rather than vertical being the main route of transmission of the virus in this country.

[Cross infection of guinea pigs with different pneumococcal serotypes in the presence of the carrier state]

The possibility of the pneumococcal cross infection of guinea pigs in experimental conditions, the time course of the distribution of pneumococci in their organs, and the duration, within the time limits of the experiment, of persistence of the given infective agent were studied. Normal animals placed in the same room with infected ones were shown to become the carriers of definite pneumococcal serotypes. As a result, these studies revealed that nasopharyngeal carriership and infection of different organs were not directly interrelated and the method of infection of guinea pigs did not influence the time course of distribution of pneumococci in their organs. The data on the duration of persistence of the infective agent, as well as on the importance of this phenomenon for determination of the relationship between pneumococcal carriership and disease, are presented.

Carriers of equine infectious anemia virus

Presently available data continue to support the idea that once a horse is infected with equine infectious anemia virus it remains infected indefinitely. Infection may not always be demonstrated by inoculation of plasma, serum, or whole blood transfusions into susceptible recipients, but transfusions of fresh whole blood will be infective in at least 95% of the horses testing positive in the agar gel immunodiffusion test. For detection of infectivity in a small percentage of inapparent carriers, it appears necessary to inoculate washed leukocytes collected over a period of time.