Seroprevalence of viral childhood infections in Eritrea.

BACKGROUND: The seroprevalence of viral childhood infections in Africa has not been thoroughly investigated. The relatively recently discovered human parvovirus B19 (B19) and human herpesvirus 6 (HHV-6) have received particularly little attention. OBJECTIVE: To investigate the seroprevalence of viral childhood infections in different Eritrean populations and to define groups at high risk for infection. STUDY DESIGN: Five population groups in Eritrea have been examined to define the prevalence of specific antibodies to several childhood viruses. The study population of more than 400 persons consisted of children, pregnant women, female sex workers and members of a secluded tribe called Rashaida. RESULTS: All groups showed a high prevalence of antibodies to measles and HHV-6 (> 85%). For rubella, the seroprevalence was very high in all adult groups (93-99%) except the Rashaida group (71%). The mumps prevalence was surprisingly low in the Rashaida group (29%) compared to 46-85% in the other adults. Late encounter of mumps and rubella was also observed among the Rashaidas. The pattern of antibodies to B19 showed a higher seroprevalence in all groups (56-91%) compared to what has been reported from the western world. CONCLUSION: The findings represent what might be expected in an unvaccinated population. The exception was the Rashaidas, which had low seroprevalences and late encounter of mumps and rubella. This is of importance because it makes this tribe vulnerable to these infections, which are associated with complications when acquired in adult age. Also noteworthy is the high frequency of antibodies to HHV-6 and particularly B19 in all groups, indicative of an early encounter of both these viruses.     

Seroprevalence of human parvovirus B19 infection in Sao Tomé and Principe, Malawi and Mascarene Islands

The prevalence of antibodies to human parvovirus B19 (anti-B19 IgG) in sera (n = 577) from Sao Tomé and Principe, Malawi and Mascarene Islands (Mauritius and Rodriguez Islands) was determined by antibody capture ELISA. The B19 prevalence was 51.5% on Sao Tomé and Principe, 58.4% in Malawi, and 55.0% on the Mauritius mainland and 2.2% on Rodriguez Island, indicating that B19 virus is highly prevalent not only in Europe, Japan and the Americas but also in the African region. Rodriguez Islands has a very low B19 prevalence.     

Simultaneous IgM reactivity by EIA against more than one virus in measles, parvovirus B19 and rubella infection.

BACKGROUND: A clinical diagnosis of rash-causing infections is not always possible and reliance has to be placed on serological evidence of infection, especially on the presence of specific immunoglobulin (Ig)M. However, despite the use of modern serological methods and validated commercial kits, reports appear in the literature of simultaneous IgM reactivity against more than one virus in cases of Epstein Barr virus, rubella, cytomegalovirus, human parvovirus B19 (HPV B19) and measles infections, all with implications for the pregnant woman. OBJECTIVES: We decided to evaluate the extent of the problem in rubella, measles and HPV B19 infections in a routine diagnostic laboratory. STUDY DESIGN: We tested sera from cases with initial clinical and serological evidence of infection with measles, HPV B19 or rubella for evidence of simultaneous IgM reactivity against more than one virus. We confirmed primary infections with specific-IgG antibody avidity tests, and subjected sera with IgM reactivity against more than one virus to avidity tests to identify which, if any, of the three viruses was the cause of the primary infection. Groups of monoreactive IgM sera were randomly selected from the presented sera to demonstrate that the avidity of the IgG specific for the other two viruses would be of high avidity compared with the low avidity of the IgG specific for the virus against which specific IgM had been detected. RESULTS: Our results confirm that simultaneous IgM reactivity against more than one virus does occur in these three infections, and that this is unlikely to be caused by the presence of rheumatoid factor. CONCLUSIONS: In the absence of seroconversion, reliance on specific IgM results alone for diagnosis of these infections should be avoided and tests such as specific IgG antibody avidity should also be employed. The simultaneous occurrence of IgM reactivity against more than one virus is also important for epidemiological and surveillance reasons as the widespread use of the mumps, measles and rubella vaccine makes its impact on the population. Falsely diagnosed cases of apparent measles or rubella could throw into question the efficacy of the vaccine.     

Detection of antibodies and antigens of human parvovirus B19 by enzyme-linked immunosorbent assay.

Acute-phase serum from a patient with aplastic crisis provided sufficient human parvovirus B19 to make a monoclonal antibody against B19 and to develop antigen and immunoglobulin M (IgM) and IgG antibody detection enzyme-linked immunosorbent assays (ELISAs). The indirect capture antibody method was used for all three assays. Antigen was detected in 8 of 29 sera drawn within 2 days of onset of illness from patients with aplastic crisis. These sera had high titers of virus by electron microscopy and DNA hybridization and had no detectable B19 antibody. Antigen was not detected in serum specimens that had low titers of B19 DNA and had B19 antibody. With the IgM ELISA, we detected B19 IgM in over 85% of clinical cases of aplastic crisis and fifth disease and less than 2% of controls. The prevalence of B19 IgG antibodies increased with age. Approximately 2% of children less than 5 years of age and 49% of adults greater than 20 years of age had B19 IgG antibodies. The B19 antibody ELISAs are sensitive and specific tests to detect B19 infections.     

Prevalence of infections affecting the child among pregnant women in Yaounde,Cameroon

The prevalence of infections which have deleterious effects to either the mother or the fetus during pregnancy are unknown in Cameroon. To formulate appropriate antenatal screening policies for the Central Mother and Child Clinic in Yaounde, we tested random sera obtained from 1,014 stored samples previously obtained from pregnant women. One hundred and fifty sera were tested for the presence of the hepatitis B surface antigen (HBsAg), 544 for syphilis antibodies, 192 for antibodies to rubella and 192 for antibodies to Toxoplasma gondii. We found the HBsAg in 25.3% (38/150) of the subjects, antibodies against syphilis in 15.9% (87/544), antibodies to the rubella virus in 83.9% (161/192) and evidence of toxoplasma infection in 77.1 % (148/192). Of the 38 HBsAg-positive subjects, 5.2% and 55.3% were positive for the HBe antigen and HBe antibody, respectively. We found a high prevalence of these infections in the antenatal clinic attendants. The data will be used to develop an appropriate control strategy for them.     

The use of labeled fusion protein for detection of B19 parvovirus IgM antibodies by an immunocapture test.

A new anti-B19 IgM ELISA was developed taking advantage of antibody-capture with biotinylated fusion protein as antigen. Specificity was examined using serum IgM antibody positive for rubella, hepatitis B core antigen, cytomegalovirus and Epstein-Barr virus as well as with sera positive for rheumatoid factors or antinuclear antibodies. The specificity was found to be 96%. Of one hundred serum samples compared using the new ELISA or the standard MACRIA tests for the presence of B19 IgM, 88 gave the same results. Fifty-three were negative and 35 were positive. Six sera were ELISA-negative MACRIA-positive, and six MACRIA-negative ELISA-positive. Thus, the ELISA gave 90% agreement with MACRIA. In a clinical study with 725 sera from suspected B19 infections, 161 (22%) were found positive by ELISA. The positive sera were from patients suffering from arthritis (35%), rash (35%), acute or chronic erythroblastopenia (21%), pancytopenia (5%), vascular purpura (2%) and lymphadenopathy (2%). A series of serum specimens obtained from two-B19 infected individuals were also studied. The IgM antibody became undetectable after four months.     

重组风疹病毒外膜蛋白E1的表达及其在血清学中的初步应用

目的 在大肠埃希菌中表达重组风疹病毒外膜蛋白E1,用其作为包被抗原,建立一种用于诊断风疹病毒感染的ELISA检测方法 .方法 通过基因重组的方式构建表达质粒并在大肠埃希菌中表达风疹病毒外膜蛋白E1,蛋白纯化后作为包被抗原,用ELISA的方法 检测世界卫生组织(WHO)的风疹检测质控血清以及来自广西桂林的未知血清样本.结果 采用WHO用于风疹检测的质控血清对所表达的重组抗原的抗原性进行鉴定,通过试验,特异性、敏感性均为100%.用表达的抗原对来自我国广西的200份未知血清样本进行风疹病毒外膜蛋白抗体的检测,阳性率为93%,与文献报道的我国其他地区风疹病毒抗体阳性率基本一致.结论 通过实验我们表达了具有良好抗原性的风疹病毒外膜蛋白E1,为进一步研究风疹病毒感染的实验室诊断技术奠定了基础.     

Current seroepidemiology of rubella virus infection among female residents in Taiwan

To examine the epidemiological characteristics of rubella virus infection on Taiwan Island and in Orchid and Pescadore islets, a community-based survey was carried out in 19 townships and metropolitan precincts randomly selected through stratified sampling. Serum specimens of 4,770 healthy girls and women randomly sampled from study areas were screened for the rubella antibody by passive latex agglutination testing and confirmed by enzyme-linked immunosorbent assay. A total of 2,934 subjects were antibody positive, giving a prevalence of 61.5%. The mean ± standard deviation of rubella IgG index was 2.51 ± 0.37. The seropositive rate increased with age in all residential areas and ethnic groups. The age pattern indicated that the regular 10-year cycle of rubella epidemic was no longer existent after 1978. A higher prevalence was observed in the eastern island and Orchid Islets compared with other areas. The highest seropositive rate was found in Orchid Islets. The overall seronegative rate was 62.9% for females <20 years of age and 36.9% for women between the ages of 20 and 29 years. With such a high susceptible density among girls and women of child-bearing ages as well as the endemicity of rubella virus infection in Taiwan, mass vaccination against rubella should be enforced in order to prevent possible future outbreaks of the congenital rubella syndrome.     

Hepatitis A and hepatitis B virus infection in children and adolescents in north-east Italy

The sera of 722 children and adolescents without overt liver disease were tested for hepatitis B surface antigen (HBsAg), antiHBs and anti-hepatitis B core anti-HBc; 658 of the sera were also tested for anti-hepatitis A virus anti-HAV. Except for the "passive" antibody peak observed in babies, the anti-HAV age-specific prevalence was negligible until the age of 3; it then increased, reaching 35% by the age of 15. Serological evidence of HBV was present in 16% of the subjects: this prevalence was almost constant at all ages. The HBsAg carrier rate was highest in children under 5 years of age (7.6%) and decreased with age. However, only one HBsAg carrier was under 1 year of age. Anti-HBs age-specific prevalence increased progressively from 2.7% to 11.4%. Anti-HBc alone was present in 4.1% of the subjects. No significant sex differences were found in the prevalence of HBV serum markers or in the HBsAg carrier rate. Neither HAV nor HBV infection was significantly influenced by place of residence or socioeconomic status. It is concluded that in this area both HAV and HBV are endemic, but while HAV is mainly acquired at school, most of the HBV infections occur within the household. The results suggest that not only perinatal transmission, but also intrafamilial horizontal infection, plays a role in HBV spread among infants.     

Circulating immune complexes in patients with acute measles and rubella virus infections

A solid-phase C1q radioimmunoassay was used to test for immune complexes (ICs) in sera obtained longitudinally from patients recovering from acute, uncomplicated measles and rubella virus infections. ICs were detected in 12 (18.5%) of 65 sera from 14 measles patients who did not have prolonged IC formation. Of 12 IC-positive measles sera, 9 were collected 4 weeks or more after rash onset. Transient appearance of detectable circulating ICs occurred sooner in 22 rubella patients who did not have prolonged IC formation. Of 109 rubella sera, 14 (12.8%) were IC-positive, and, of these, 10 were collected within 3 weeks of rash onset. Prolonged IC formation was found for an additional four measles and two rubella virus patients. Fractionation of sera from these six patients revealed that levels of large-sized ICs were highest in the initial 10 days after rash onset. Levels of large-sized ICs then declined to those for medium- and small (approximately immunoglobulin G)-sized ICs. IC-associated virus-specific antigens were detected in some of the sera from the six patients having prolonged IC formation. These results suggest two things: first, measles and rubella virus patients differ in the timing of virus clearance or in the reestablishment of normal immunity after infection; second, virus clearance is prolonged in some measles and rubella virus patients who have seemingly normal recoveries from their infections.     

Clinical evaluation of the sensitivity and specificity of a commercially available enzyme immunoassay for detection of rubella virus-specific immunoglobulin M.

A solid-phase capture antigen enzyme immunoassay (Rubazyme-M) was evaluated for sensitivity and specificity on sera from 1,200 blood donors, 51 patients with rubella, 2 infants with congenital rubella, 104 patients with other infections, and 126 patients with immunological abnormalities. The sensitivity was 100% for sera tested between days 3 and 40 after the onset of symptoms of rubella virus infection. Rubella virus-specific immunoglobulin M was detected at birth in sera from congenitally infected infants and persisted for several months. Positive Rubazyme-M responses were observed in some patients in the absence of rubella diagnosis (one blood donor, three other infections, and two immunological abnormalities), providing a test specificity of 99.6%. None of 67 patients with rubella virus-specific immunoglobulin G antibody and high levels of rheumatoid factor were positive in the test.     

重组人干扰素α-2b喷雾剂在人群中对风疹、麻疹病毒减毒活疫苗鼻腔接种后干预免疫效果的初步研究

目的初步观察重组人干扰素α2b(rhIFNα2b)鼻腔喷雾剂对风疹、麻疹减毒活疫苗鼻腔接种后免疫效果的干预作用。方法选择合适人群进行对比试验,一组为干扰素(IFN)试验组,一组为对照组。IFN试验组提前2天使用rhIFNα2b喷雾剂,然后IFN试验组和对照组分别使用风疹、麻疹减毒活疫苗进行鼻腔接种。在疫苗接种前以及接种后第21和28天分别采集试验对象血清测定其对应的IgG特异性抗体,以抗体滴度的差异观察IFNα2b对病毒感染的干预效果。结果麻疹试验组和对照组的抗体差异分别为1.26(21d)和2.96(28d),差异有统计学意义;风疹试验组和对照组的抗体差异为0.95(21d)和0.37(28d),差异不明显。结论⑴单价麻疹和风疹疫苗鼻腔喷雾接种可以加强基础免疫;⑵rhIFNα2b鼻腔喷雾剂对风疹和麻疹减毒活疫苗鼻腔接种的免疫效果有一定的干预作用。     

吉林省供血者人类细小病毒B19 IgG抗体的调查

目的 了解吉林省供血者人类细小病毒感染的流行病学情况,为评估我国B19病毒的感染状况提供基础数据.方法 用间接ELISA方法检测血清中的抗B19 IgG抗体.结果 在184份血清中,抗B19 IgG抗体总检出率为55.43%.女性抗体阳性率高于男性,差异有统计学意义（P＜0.05）,年龄段在35～45岁之间的献血人员抗体阳性率最高.结论 本研究数据提示吉林省地区献血人员B19病毒感染率较高,有必要进行进一步B19 DNA的调查研究,为输血安全和血液制品安全提供保障.     

High level expression of recombinant mumps nucleoprotein in Saccharomyces cerevisiae and its evaluation in mumps IgM serology.

To develop improved reagents for mumps serology a high-level yeast expression system was employed to produce recombinant mumps nucleoprotein (rNP). The rNP was purified by CsCl gradient centrifugation and yielded approximately 15 mg/l of yeast culture. Electron microscopy of the rNP revealed characteristic herring-bone structures. The electrophoretic mobility of rNP in yeast cells was similar to native NP in SDS-PAGE. Monoclonal antibodies to rNP reacted with native mumps virus nucleoprotein by immunofluorescence assay. A monoclonal antibody to native mumps virus NP reacted with rNP by Western blot assay. The rNP was investigated as antigen in an IgM capture enzyme immunoassay (EIA) using a horseradish peroxidase conjugate of monoclonal antibody to the rNP. Eighteen sera previously found to be positive by IgM capture radioimmunoassay (MACRIA) and 30 sera that were mumps IgM negative by MACRIA were tested by mumps IgM capture EIA. The results for the two test were concordant. In addition, 26 rheumatoid factor positive sera and 35 sera that were IgM positive for measles, rubella or parvovirus B19 were tested. Fifty-nine sera were negative by mumps IgM capture EIA but two sera collected from two infants 3 and 6 weeks after mumps, measles and rubella vaccination were positive. Mumps MACRIA confirmed these results. Compared to MACRIA the overall sensitivity was 100% (20/20) and specificity was 96.8% (30/31). The yeast expressed rNP was highly immunogenic and suitable for use in IgM capture EIA for the diagnosis of mumps.     

Decay of passively acquired maternal antibodies against measles, mumps, and rubella viruses.

The decay of maternally derived antibodies to measles, mumps, and rubella viruses in Swiss infants was studied in order to determine the optimal time for vaccination. A total of 500 serum or plasma samples from infants up to 2 years of age were tested by enzyme-linked immunosorbent assay and fluorescent-antibody testing. The decline of antibody prevalence was slowest against the measles virus. By 9 to 12 months of age, only 5 of 58 (8.6%; 95% CI, 2.9 to 19.0) infants were antibody positive for the measles virus, and only 2 had levels above 200 mIU/ml. Mumps and rubella virus antibody seropositivity was lowest at 9 to 12 months of age with 3 of 58 (5. 2%; 95% CI, 1.1 to 14.4) infants and at 12 to 15 months with 1 of 48 (2.1%; 95% CI, 0.1 to 11.1) infants, respectively. Concentrations of passively acquired antibodies decreased rapidly within the first 6 months of life. We observed no significant differences in antibody prevalence or concentration according to gender in any age group. In conclusion, MMR vaccination at 12 instead of 15 months of age could reduce the pool of susceptible subjects in infancy and support the efforts to eliminate these infections, particularly in combination with a second vaccine dose before school entry.     

Development and evaluation of a capture enzyme-linked immunosorbent assay for determination of rubella immunoglobulin M using monoclonal antibodies.

A capture enzyme-linked immunosorbent assay (ELISA) for detection of virus-specific immunoglobulin M (IgM) antibody was developed which used a panel of labeled monoclonal antibodies to rubella virus hemagglutinin. The rapidity of the test system was increased by using, after 1-h incubation of the test serum, a second 1-h incubation of the serum with a mixture of viral antigen and labeled monoclonal antibody. The new assay was tested for specificity on 371 human sera from people without any recent contact with rubella virus; of these, 66 were sera selected from people with rheumatoid factor or IgM antibody to human cytomegalovirus, Epstein-Barr virus, or other viruses. In parallel, the new assay was performed on 191 sera from patients having recent contact with rubella virus. Results were compared with those obtained by an indirect ELISA method on IgM serum fractions, using purified rubella virus as a solid phase. Of the 371 sera tested for specificity, 5 (1.3%) gave false-positive results with indirect ELISA (1 rheumatoid factor, 2 heterophil antibody, and 2 human cytomegalovirus sera positive for IgM), and none were false-positive with the capture assay. Two sera from a patient with primary cytomegalovirus infection, which were positive for rubella IgM antibody with both methods and were initially interpreted as false-positive, were finally considered to be true-positive, since they were reactive only in the presence of IgM antibody and viral antigen. Of the 191 sera from 92 patients (84 patients with acute rubella, four newborns from mothers with rubella during pregnancy, and four vaccinees), 136 (71.2%) were found to be positive for IgM by direct ELISA, and 128 (67.0%) were positive by capture ELISA; 12 sera drawn during the first 2 days of disease, or at least 40 days after onset (or after vaccination), were detected only by indirect ELISA, and 4 sera were detected only by capture ELISA. Thus, specificity and sensitivity, respectively, were 100 and 91.4% for capture ELISA and 98.6 and 97.1% for indirect ELISA. However, when the number of patients was considered, 86 were detected as IgM positive by indirect ELISA, and 87 were detected positive by capture ELISA. The overall agreement between the two assays was 96.2%. Capture ELISA using monoclonal antibody appears preferable over indirect ELISA on IgM serum fractions because of its higher specificity and shorter time for test performance; furthermore, there is no need for serum fractionation or virus purification for the capture ELISA.     

Kinetics of rubella-specific IgM antibody response in postnatal rubella infection

The serological diagnosis of primary postnatal rubella infection is based on detection of rubella-virus-specific IgM antibody or a four-fold rise in rubella-specific IgG antibody. Although there are several different methods of enzyme immunoassays that are commercially available, the cost benefit evaluation makes them impractical for use in developing countries. For this reason, we have standardized the measurement of rubella IgM antibody by HAI following serum fractionation by ion-exchange chromatography. The sera samples obtained from pregnant women infected with rubella virus at different times during gestation were fractionated and tested by HAI. Seven out of nine sera collected within the first two days after onset of rash showed detectable levels of rubella IgM antibody. All 57 sera collected between 3 and 30 days after the onset of rash contained rubella IgM antibody. After 30 days, only 1 of 5, or 20%, of sera contained IgM antibody. The HAI testing method was rapid and specific and the cost was not prohibitive. HAI-IgM testing could be used to diagnose primary rubella infections in developing countries where expensive EIAs are unaffordable.     

Distribution of antibody to hepatitis a antigen in urban adult populations.

To investigate the prevalence and distribution of antibody to hepatitis A antigen we tested 947 randomly selected people in the Greater New York City area; 45 per cent were antigen positive, as determined by the immune adherence method. Antibody was detected two to three times more frequently in lower social classes (72 to 80 per cent) than in middle and upper-middle classes (18 to 30 per cent). The rate of antibody detection was strongly correlated with age; the prevalence gradually increased throughout adulthood and reached its peak level in people 50 years of age and older. Those with serologic evidence of past exposure to hepatitis B virus were significantly more often antibody positive than those without such evidence (61 vs. 40 per cent; P less than 0.001). Very few of the positive subjects had had hepatitis. The prevalence of this antibody varies among different population groups, increases with age, decreases with rise in socioeconomic status, is independent on sex and race, and correlates with serologic evidence of hepatitis B virus infections.     

Prevalence of herpes simplex virus types 1 and 2, cytomegalovirus, and varicella-zoster virus infections in Eritrea.

BACKGROUND: Herpesviruses establish latent infections in their hosts for life. The scarcity of data that exists in regard to herpesvirus infections in many African regions, could partly be due to the mild nature of their primary infections and the lack of means for their proper diagnosis. However, in recent decades the alarming spread of HIV infection in Africa and associated frequent reactivation of herpesvirus infections is leaving less room for neglect. This seroprevalence study is intended to help in the evaluation of the prevalence of herpesvirus infections in Eritrea. OBJECTIVE: To evaluate the spread of herpes simplex virus types 1 and 2 (HSV-1 and HSV-2), cytomegalovirus (CMV), and varicella-zoster virus (VZV) infections. STUDY DESIGN: The study population groups comprise female sex workers (FSW), former guerrilla fighters, truck drivers, port workers, a tribe called Rashaida, pregnant women, children under 5 years of age, and children over 5 years of age. The groups of pregnant women and children under and over 5 years of age were included to form a background for the evaluation of groups considered at risk for sexually transmitted or blood borne infections. RESULTS: All study groups had a high seroprevalence of HSV-1 infections ( > 80%), except for the children under 5 years of age. The FSW had the highest prevalence of HSV-2 infections, 80%, followed by guerrilla fighters, truck drivers, port workers, pregnant women, children, and the Rashaidas. Positivity for antibodies against CMV was > 90% in all studied populations. The prevalence of VZV infections was surprisingly low in the tribe of Rashaida, 44% compared to more than 90% in the other adult groups tested for VZV (P = 0.0001). CONCLUSION: The study shows that the prevalence of HSV-2 in the risk group of FSW was high, which could partly be explained by their sexual behaviours. HSV-2 was particularly low in the Rashaida group and, as expected, in the children. The low prevalence of VZV observed in the Rashaida is of importance since it makes them vulnerable to infection with varicella during their inevitable integration with the other tribes in their society.     

Seroepidemiology of hepatitis A, B, and D viruses and human T-lymphocyte tropic viruses in Japanese drug abusers

To evaluate the prevalence of hepatitis virus markers and human T-cell lymphotropic virus infections among drug abusers in Japan, serum samples were collected from 91 male drug abusers at the Shinshu University Hospital and the rehabilitation facility in Matsumoto and from 519 healthy male blood donors as controls. Sera were tested for antibody to hepatitis A virus (anti-HAV), hepatitis B surface antigen (HBsAg), antibody to HBsAg (anti-HBs), antibody to hepatitis B core antigen (anti-HBc), immunoglobulin M anti-HBc (IgM anti-HBc), antibody to hepatitis D virus (anti-HDV), antibody to HTLV type 1 (anti-HTLV 1), and antibody to human immunodeficiency virus (anti-HIV). The prevalence of anti-HAV was 13.2% in drug abusers and 10.8% in controls (not significant). The prevalences of HBsAg, anti-HBs, anti-HBc and exposure rate to hepatitis B virus (HBV) were 4.4%, 24.2%, 31.9%, and 35.2%, respectively, in drug abusers and 0.8%, 6.7%, 9.6%, and 9.6% in controls. The exposure rate to HBV was significantly different (P less than 0.001). IgM anti-HBc and anti-HDV were not detected in any sera. Anti-HTLV I was detected in three drug abusers (3.3%) and in one (0.2%) of the controls (P less than 0.01). All sera were negative for anti-HIV in all subjects. Infection with HBV and HTLV I is more common among drug abusers than in the general population of blood donors in Japan.