Seropositivity to anti-phenolic glycolipid-I in leprosy cases, contacts and no known contacts of leprosy in an endemic and a non-endemic area in northeast Brazil

The seroprevalence rates of IgM anti-phenolic glycolipid-I (PGL-I) antibodies in four study groups with differing exposure to Mycobacterium leprae in Ceará, Brazil were investigated between March 2005 and August 2006. The first three groups in a high prevalence area included 144 cases of leprosy, their 380 contacts and 317 participants with no known leprosy contact. The fourth group in a low prevalence area consisted of 87 participants with no known leprosy contact living in an area in which no cases of leprosy had been reported in the previous 6 months. Seropositivity and levels of IgM antibodies to PGL-I were investigated using ELISA. The seropositivity levels of anti-PGL-I among the different clinical forms of leprosy cases were 61% for lepromatous, 25% for tuberculoid and 27% indeterminate. The levels of anti-PGL-I antibodies in the endemic area differentiated leprosy cases from non-cases. However, the seropositivity was similar among contact cases (15.8%) and no known leprosy contact cases from high (15.1%) and low (13.8%) prevalence areas. The seropositivity of both contacts and no known contacts was much higher than previously reported among no known contacts in other endemic areas. The study indicates that anti-PGL-I antibodies are not useful as immunological markers of household leprosy contacts and no known leprosy contacts in endemic areas.     

Detection of high titres of Toxoplasma gondii antibodies in sera of patients with leprosy in Pakistan.

Untreated and treated leprosy patients and their household contacts were screened for antibody to Toxoplasma gondii using antigen-coated latex particles. A significantly high level of seroprevalence (29.6%) was observed in the untreated leprosy patients compared to endemic controls (P < 0.01) with a mean reciprocal antibody titre of 20,007 +/- 3580 (n = 98) in seropositive patients. In treated patients seroprevalence dropped to 13.5%. Seroprevalence in a group of household contacts of leprosy patients was similar to that of control subjects from an endemic area but not exposed to leprosy (7.8% and 6.1% respectively), indicating that the increased seroprevalence in leprosy patients was not merely due to increased exposure related to socioeconomic factors. Antigenic cross-reactivity between T. gondii and Mycobacterium leprae antigens was ruled out by cross inhibition experiments carried out with soluble antigens from each of the organisms. We believe these antibodies may be induced by an increase in T. gondii load in leprosy due to a transient reactivation of latent T. gondii infections, as the antibodies in these leprosy patients were not associated with any sign of eye or lymphatic pathology related to toxoplasmosis.     

云南省丘北县麻风持续传播影响因素的研究

目的 探讨云南省丘北县多种药物联合化疗实施25年后麻风仍持续传播的影响因素.方法 分别采用ELISA、PCR检测高流行区患者与家庭内接触者、普通人群血清中麻风菌特异性PGL-1抗体以及鼻分泌物中的麻风菌,采用PCR方法检测疫村环境水中的麻风菌.采用数目可变的串联重复序列基因分型方法探讨麻风菌传播途径及传播链等.结果 在2001年以前从麻风患者家庭成员中检测到的比例低,而延迟期>2年患者的检出比例高.2001年后防治工作加强使这两个指标改进,但麻风发现率仍一直维持在4/10万至5/10万.疫村人群PGL-1抗体阳性率为20%～30%,主要感染人群为青少年;不仅从患者、家内接触者的鼻分泌物与环境水中检出麻风菌,且与未经治疗患者的皮肤组织和鼻分泌物中麻风菌基因型一致.菌株分型证实该县北部地区不仅有多个高发家庭聚集,而且家庭内患者的菌株基因型一致.在北部地区基因型匹配菌株的比例高于南部地区.结论 丘北县麻风在家庭内和疫村中的传播严重,疫村环境水中存在麻风菌等是影响该病持续传播的重要因素.

Abstract：

Objective To explore the factors influencing the steady transmission of leprosy as indicated by new case detection rate in Qiubei county, Yunnan province, China despite the implementation of MDT for the last 25 years. Methods Information related to case-finding was collected. ELISA and PCR were applied to detect anti-PGL-1 antibody in sera and Mycobacterium leprae in nasal secretions respectively, in leprosy patients, their household contacts and the general population. M. leprae by PCR was also detected from water in the highly endemic villages. VNTR typing was performed to explore the mode and chain of transmission of M. leprae. Results Prior to 2001, the proportion of new cases detected from the examination of household contacts of leprosy patients was low (number, compared to), while the proportion of patients whose identification was delayed by more than 2 years, was high (number, compared to). Qualities of these two indicators has been improved, along with the improvement of leprosy control program since 2001, but the detection rates has been steady at 4-5/ 100 000 during 1986-2010. The PGL-1 seropositivity rate was 20%-30% in general population, with the peak rate (30%) detected in the teenage population in the endemic villages. In addition to the fact that M. leprae was detected in nasal secretion from patients, their contacts and from water, the M. leprae VNTR genotypes were found to be highly similar between skin biopsy and nasal secretion in untreated cases. Families with multi-cases were clustered and located in the Northern part of the County, and the genotypes of M. leprae were identical within those families. The percentage of clusters was considerably higher in Northern rather than Southern parts of the County. Conclusion Results from this molecular study demonstrated evidence that transmission of leprosy within the families and in the endemic-villages was severe. M. leprae were detected in waters from the endemic villages and others areas which might have a relation to the continued transmission of leprosy.     

云南省丘北县麻风持续传播影响因素的研究

目的 探讨云南省丘北县多种药物联合化疗实施25年后麻风仍持续传播的影响因素.方法 分别采用ELISA、PCR检测高流行区患者与家庭内接触者、普通人群血清中麻风菌特异性PGL-1抗体以及鼻分泌物中的麻风菌,采用PCR方法检测疫村环境水中的麻风菌.采用数目可变的串联重复序列基因分型方法探讨麻风菌传播途径及传播链等.结果 在2001年以前从麻风患者家庭成员中检测到的比例低,而延迟期>2年患者的检出比例高.2001年后防治工作加强使这两个指标改进,但麻风发现率仍一直维持在4/10万至5/10万.疫村人群PGL-1抗体阳性率为20%～30%,主要感染人群为青少年;不仅从患者、家内接触者的鼻分泌物与环境水中检出麻风菌,且与未经治疗患者的皮肤组织和鼻分泌物中麻风菌基因型一致.菌株分型证实该县北部地区不仅有多个高发家庭聚集,而且家庭内患者的菌株基因型一致.在北部地区基因型匹配菌株的比例高于南部地区.结论 丘北县麻风在家庭内和疫村中的传播严重,疫村环境水中存在麻风菌等是影响该病持续传播的重要因素.     

Hepatitis A seroprevalence in adolescents and young adults in Mexico: A 2012 National Health and Nutrition Survey analysis

To describe hepatitis A virus (HAV) seroprevalence and associated factors in adolescents (10–19 years) and young adults (20–25 years) in different Mexican regions, using 2012 National Health and Nutrition Survey data. A random selection of 1581 serum samples was analyzed. Weighted HAV seroprevalence with 95% confidence intervals (95%CI) and its association with sociodemographic factors were estimated. Mean weighted HAV seroprevalence was 69.3% (95%CI: 64.8–73.4) overall, with 58.8% (95%CI: 53.4–64.1) in adolescents and 83.0% (95%CI: 75.3–88.7) in young adults. By age of 10, 46.7% (95%CI: 33.9–60.0) were seropositive and by age of 15, 52.8% (95%CI: 36.5–68.5), corresponding to intermediate endemicity nationally. Factors associated with HAV seropositivity (adjusted odds ratio, aOR) included: lower socioeconomic status (SES) (aOR = 4.09 for low and aOR = 2.31 for medium versus high SES), older age (aOR = 0.29 for adolescents versus young adults), living in the South (aOR = 2.12 versus Central Mexico) or in rural areas (aOR = 2.25 versus urban areas). Regional differences and increased seroprevalence of HAV in marginalized populations present an important public health issue, as a relatively large proportion of young adults are susceptible to infection. The burden of symptomatic disease must be addressed further to support specific programs of continued sanitation and education improvement, and the possibility of vaccination in more susceptible regions.     

Developing and using a PCR test to detect subclinical Mycobacterium leprae infection]

OBJECTIVE: While the prevalence of leprosy has declined around the world, there has not been a corresponding decrease in its incidence, thus indicating that it has not been possible to prevent transmission of the disease. Despite the small number of patients with lepromatous leprosy, the majority of the inhabitants of endemic areas show signs of exposure to Mycobacterium leprae, which could be explained by the presence of subclinical bacilliferous infections in the community. The objective of this study was to investigate the use of a polymerase chain reaction (PCR) test to detect M. leprae in samples of nasal mucus from asymptomatic household contacts of patients with leprosy. METHODS: We standardized and optimized a PCR technique to amplify a 321 base pair DNA fragment, using a pair of primers complementary to a segment of an LSR/A15 gene that codes for the 15 kDa M. leprae antigen. We investigated the optimal concentrations of all the test components. We used dimethyl sulfoxide (DMSO) to achieve a more specific amplification. We applied the PCR test to 70 healthy household contacts of leprosy patients from eight municipalities in Colombia where there was a high prevalence of the disease. RESULTS: The test's detection limit was 100 fg of DNA. With the optimized technique, bacillus was detected in the nasal mucus samples of 9 (12.8%) of the 70 household contacts. The 3 PCR-positive household contacts of paucibacillary cases were from municipalities with very high prevalence levels. In comparison to contacts who were PCR-negative, the contacts who were PCR-positive had spent significantly less time, as a proportion of their age, living with a patient (P = 0.028). This finding demonstrates the test's capacity for early detection. CONCLUSIONS: The PCR test that we developed is useful as a tool for detection and early follow-up of possible leprosy cases. It can be used to monitor high-risk populations and also to maintain the achievements of leprosy elimination programs in countries where the disease's prevalence has been significantly reduced.     

Social distance and spatial distance are not the same, observations on the use of GIS in leprosy epidemiology

Contacts of leprosy patients have a higher risk of developing clinical leprosy. Being a contact is defined socially, but with the introduction of geographical information systems (GIS) in infectious disease epidemiology, it is necessary to relate spatial distance to social distance. We measured the distances between patients and their socially defined contacts in northwest Bangladesh. Contact categories differ in mean distance to the index patients. Sixty-seven per cent of the high-risk contacts lived within 10 metres (m), while all low-risk contacts lived >10 m from the index patient. Classification based on intervals of spatial distance creates categories that contain contacts of different socially defined categories, illustrated by a category of people living between 10 m and 20 m consisting of 47% of high-risk contacts and 52% low-risk contacts. Classification of contacts based on the spatial distance, as performed with GIS techniques, produces other groups than with social definitions.     

SARS-CoV-2 Seroprevalence among Healthcare,First Response,and Public Safety Personnel,Detroit Metropolitan Area,Michigan, USA,May–June 2020

To estimate seroprevalence of severe acute respiratory syndrome 2 (SARS-CoV-2) among healthcare, first response, and public safety personnel, antibody testing was conducted in emergency medical service agencies and 27 hospitals in the Detroit, Michigan, USA, metropolitan area during May–June 2020. Of 16,403 participants, 6.9% had SARS-CoV-2 antibodies. In adjusted analyses, seropositivity was associated with exposure to SARS-CoV-2–positive household members (adjusted odds ratio [aOR] 6.18, 95% CI 4.81–7.93) and working within 15 km of Detroit (aOR 5.60, 95% CI 3.98–7.89). Nurse assistants (aOR 1.88, 95% CI 1.24–2.83) and nurses (aOR 1.52, 95% CI 1.18–1.95) had higher likelihood of seropositivity than physicians. Working in a hospital emergency department increased the likelihood of seropositivity (aOR 1.16, 95% CI 1.002–1.35). Consistently using N95 respirators (aOR 0.83, 95% CI 0.72–0.95) and surgical facemasks (aOR 0.86, 95% CI 0.75–0.98) decreased the likelihood of seropositivity.     

用巢式聚合酶链式反应从全血扩增麻风菌特异片段提高麻风病确诊率

目的用巢式聚合酶链式反应(Nested-PCR)检测全血中麻风菌特异片段,以提高麻风病诊断水平。方法收集多菌型(multibacillary leprosy,MB)、少菌型(paucibacillary leprosy,PB)麻风病患者、其家庭内接触者以及麻风病流行区、非流行区的正常人全血和血清样本,建立巢式PCR,扩增麻风菌重复序列的特异片段,PCR阳性产物直接测序鉴定扩增片段的特异性。结果在35例MB患者中巢式PCR有34例阳性;26例PB患者中19例阳性;23例家庭内接触者中2例阳性。流行区和非流行区正常人中未见阳性。此结果与血清学结果进行比较,发现血清学检测MB患者阳性率稍高于巢式PCR;值得注意的是,对PB患者中细菌密度指数(BI)为阴性者,巢式PCR阳性检测率高达78.57%。结论巢式PCR对于麻风病MB患者的诊断敏感性不亚于血清学抗体诊断,但可提高麻风病特别是对PB患者诊断的敏感性;对高危人群尤其是家庭内接触者的监测有较大的实用价值。     

Prevalence of SARS-CoV-2 Antibodies in First Responders and Public Safety Personnel,New York City,New York,USA, May–July 2020

We conducted a serologic survey in public service agencies in New York City, New York, USA, during May–July 2020 to determine prevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection among first responders. Of 22,647 participants, 22.5% tested positive for SARS-CoV-2–specific antibodies. Seroprevalence for police and firefighters was similar to overall seroprevalence; seroprevalence was highest in correctional staff (39.2%) and emergency medical technicians (38.3%) and lowest in laboratory technicians (10.1%) and medicolegal death investigators (10.8%). Adjusted analyses demonstrated association between seropositivity and exposure to SARS-CoV-2–positive household members (adjusted odds ratio [aOR] 3.52 [95% CI 3.19–3.87]), non-Hispanic Black race or ethnicity (aOR 1.50 [95% CI 1.33–1.68]), and severe obesity (aOR 1.31 [95% CI 1.05–1.65]). Consistent glove use (aOR 1.19 [95% CI 1.06–1.33]) increased likelihood of seropositivity; use of other personal protective equipment had no association. Infection control measures, including vaccination, should be prioritized for frontline workers.     

Cross-reactivity of Mycobacterium leprae and M. tuberculosis and the implications for assessment of in vitro T cell function in leprosy patients

The cross-reactivity in vitro between Mycobacterium leprae and M. tuberculosis was studied in 41 Aboriginal Australians with leprosy, 78 uninfected contacts of leprosy patients and 38 control individuals. A vigorous T cell response to epitopes cross-reactive between these two mycobacteria was found for healthy uninfected contacts or non-contacts (controls) of leprosy patients, but not for the patients themselves. The data suggest that a vaccine based on antigen shared between M. leprae and other mycobacteria is unlikely to be useful in preventing leprosy. Further studies of responses in vitro to purified T cell-reactive antigens would be useful in designing newer vaccines for more widespread field studies of leprosy prevention.     

Detection of viable Mycobacterium leprae in soil samples: Insights into possible sources of transmission of leprosy

Leprosy has ceased to be a public health problem world wide, after the successful implementation of effective chemotherapy (MDT) and use of control measures. However, new cases of leprosy continue to occur. Mycobacterium leprae cannot be grown in any acceptable culture medium and besides the wild armadillos, there is no known animal reservoir for leprosy. The transmission of leprosy is believed to be due to a large extent by droplet discharge of bacilli through nose and mouth and to a lesser extent by direct contact of susceptible host with a patient for long duration. The exact role of the environment in the transmission dynamics is still speculative. In the present study, we have tried to detect viable M. leprae from soil samples in endemic areas by using molecular methods. Eighty soil samples were collected from villages of this area, DNA and RNA of M. leprae extracted and identified using specific M. leprae primers. PCR amplification was done and real-time RT-PCR was used to detect viable M. leprae. DNA targeting the 16S region of M. leprae was detected in 37.5%, whereas M. leprae RNA targeting the same region was detected in 35% of these samples. Of the total 80 samples, 40 were collected from residential areas of leprosy patients whereas 40 samples were from no-patient areas. Fifty-five percent positivity for 16S rRNA of M. leprae was observed from the "patient" area in comparison to 15% positivity from the "no-patient" area (p<0.001). This study thus provides valuable information of presence of viable M. leprae in soil specimens, which would be of use in investigating the transmission dynamics in leprosy.     

Detecting spatial clusters of Taenia solium infections in a rural block in South India

Neurocysticercosis (NCC) is a major cause of seizures/epilepsy in countries endemic for the disease. The objectives of this study were to spatially map the burden of active epilepsy (AE), NCC, taeniasis, seroprevalence for cysticercal antibodies and positivity to circulating cysticercal antigens in Kaniyambadi block (approximately 100 villages comprising 100 000 population) of Vellore district and to detect spatial clusters of AE, NCC, taeniasis and seroprevalence. Using geographic information system (GIS) techniques, all 21 study villages with over 8000 houses (population of 38 105) were mapped. Clustering of different indices of Taenia solium infection was determined using a spatial scan statistic (SaTScan). There was a primary spatial cluster of AE with a log likelihood ratio (LLR) of 10.8 and relative risk (RR) of 22.4; however, no significant clustering for NCC was detected. Five significant spatial clusters of seropositivity for cysticercal antibodies, two clusters of seropositivity for cysticercal antigens and one for taeniasis were detected (LLR of 8.35 and RR of 36.67). Our study has demonstrated the use of GIS methods in mapping and identifying ‘hot spots’ of various indices of T. solium infection in humans. This spatial analysis has identified pockets with high transmission rates so that preventive measures could be focused on an intensive scale.     

Leptospiral infection among primitive tribes of Andaman and Nicobar Islands.

The Andaman islands were known to be endemic for leptospirosis during the early part of the century. Later, for about six decades no information about the status of the disease in these islands was available. In the late 1980s leptospirosis reappeared among the settler population and several outbreaks have been reported with high case fatality rates. Besides settlers, these islands are the home of six primitive tribes of which two are still hostile. These tribes have ample exposure to environment conducive for transmission of leptospirosis. Since no information about the level of endemicity of the disease among the tribes is available, a seroprevalence study was carried out among all the accessible tribes of the islands. A total of 1557 serum samples from four of the tribes were collected and examined for presence of antileptospiral antibodies using Microscopic Agglutination Test (MAT) employing 10 serogroups as antigens. An overall seropositivity rate of 191% was observed with the highest rate of 53.5% among the Shompens. The seropositivity rates in the other tribes were 16.4% among Nicobarese, 222% among the Onges and 14.8% among the Great Andamanese. All of the tribes except the Onges showed a similar pattern of change in the seroprevalence rates with age. The prevalence rates were rising from low values among children to reach a peak in those aged 2140 years and then declined. Among Onges the seroprevalence rates continued to rise beyond 40 years. In all the tribes, seroprevalence rates were found to be significantly higher among the males. The commonest serogroups encountered were Australis followed by Grippotyphosa, Icterohaemorrhagiae, Pomona and Canicola.     

南京市2018年艾滋病防治三个90%策略的进展及影响因素

目的  分析南京市2018年艾滋病防治策略“三个90%”目标的进展情况及其实现的影响因素。 方法  从艾滋病防治综合信息系统中获取南京市现存活的人类免疫缺陷病毒(human immunodeficiency virus, HIV)感染者/艾滋病(acquired immune deficiency syndrome, AIDS)患者检测发现、抗病毒治疗(antiviral therapy, ART)和病毒载量(viral load, VL)相关信息,分析“三个90%”进展情况,采用多因素Logistic回归分析模型分析影响因素。 结果  2018年南京市“三个90%”目标分别达到74.0%、88.5%和96.7%。经同性传播的HIV/AIDS检测发现率较低(χ² =86.15, P < 0.001)。注射吸毒传播(aOR=0.263,95% CI：0.156~0.442,P < 0.001)、 < 25岁年龄组(aOR=0.697,95% CI：0.540~0.899,P=0.005)以及监管场所发现(aOR= 0.353,95% CI：0.193~0.646,P=0.001)的HIV/AIDS治疗覆盖率较低;而同性传播(aOR=1.840,95% CI：1.390~2.434,P < 0.001)、35~44岁年龄组(aOR=1.826,95% CI：1.260~2.645,P=0.001)、汉族(aOR=1.797,95% CI：1.038~3.109,P=0.036)、大专及以上文化程度(aOR=1.652,95% CI：1.005~2.717,P=0.048)、已婚有配偶(aOR=1.466,95% CI：1.051~2.046,P=0.024)的HIV/AIDS治疗覆盖率较高。 结论  南京市朝着2020年实现“三个90%”的防治目标迅速迈进,但仍有一定的挑战,需要继续扩大HIV检测发现,加强吸毒人群、低龄和老年人等重点人群治疗关怀服务。     

Seroprevalence and risk factors for brucellosis in a high-risk group of individuals in Bangladesh

Brucellosis is an occupational hazard of livestock farmers, dairy workers, veterinarians, slaughterhouse workers, and laboratory personnel, all of whom are considered to belong to the high-risk occupational group (HROG). A study was undertaken to determine the seroprevalence of brucellosis, identify risk factors associated with brucellosis seropositivity, and detect Brucella at genus level using real-time polymerase chain reaction (PCR) among people in the HROG in the Dhaka division of Bangladesh. A sample of 500 individuals from the HROG was collected from three districts of Dhaka division of Bangladesh. A multiple random effects logistic regression model was used to identify potential risk factors. Two types of real-time PCR methods were applied to detect Brucella genus-specific DNA using serum from seropositive patients. The prevalence of brucellosis based on the three tests was observed to be 4.4% based on a parallel interpretation. The results of the multiple random effects logistic regression analysis with random intercept for district revealed that the odds of brucellosis seropositivity among individuals who had been in contact with livestock for more than 26 years was about 14 times higher as compared to those who had less than 5 years of contact with livestock. In addition, when the contact was with goats, the odds of brucellosis seropositivity were about 60 times higher as compared to when contact was with cattle only. Noticeable variation in brucellosis seropositivity among humans within the three districts was noted. All of the 13 individuals who tested positive for the serological tests were also positive in two types of real-time PCR using the same serum samples. Livestock farmers of brucellosis positive herds had a significantly higher probability to be seropositive for brucellosis. The study emphasized that contact with livestock, especially goats, is a significant risk factor for the transmission of brucellosis among individuals in the HROG.     

贵州兴义市麻风菌株基因分型及传播链分析

目的根据麻风菌株基因型分析传播链特点。方法对2004—2009年贵州省兴义市发现的50例新发和复发麻风病患者的菌株17个串联重复序列（VNTR）位点分型,结合患者地理分布分析病例感染、传播之间的流行病学特征。结果根据AC8b、AC9、AC8a、6-7等位点基因型,兴义市流行的麻风菌有6种基因型相似的聚类株,兴义菌株在 rpoT、21-3、27-5、23-3和（GGT）5位点的拷贝数完全一致,但2号和5号聚集株在12-5位点和18-8位点的拷贝数分别是4,为兴义市所特有菌株;为聚集株的26例患者中,有7例为复发病例,21例有明确的感染传播关系;1号和4号聚类株内的15例患者（57.7%）主要分布在兴义市东南部,4号聚类株为聚集在同一自然村内的布依族患者;家内患者之间感染的菌株基因型不相同。结论兴义市多种菌株与特有菌株长期共存是兴义麻风病高流行的重要因素,具有麻风易感体质的家内成员可感染周围存在的不同菌株而发病;为阻断传播,针对家内接触者和高发乡村加强发现早期病例和进行化学预防很有必要。     

Population-based Toxoplasma seroprevalence study in The Netherlands

During 1995--1996 a population-based seroprevalence study was conducted in The Netherlands. Risk factors were established for postnatally acquired toxoplasmosis. The results were compared with a study conducted during 1987-1988 in pregnant women in the Southwest of The Netherlands in order to estimate the change in seroprevalence. In total, 7521 sera were tested and the national seroprevalence was 40.5 % (95 % CI 37.5-43.4). Living in the Northwest, having professional contact with animals, living in a moderately urbanized area, being divorced or widowed, being born outside The Netherlands, frequent gardening and owning a cat were independently associated with Toxoplasma seropositivity. Risk factors like eating undercooked meat could not be studied. The seroprevalence among women aged 15-49 years was 10 % lower (35.2 %, 95 % CI 32.9-38.6) in the study of 1995-1996, compared to the Toxoplasma study of 1987--1988 (45.8 %, 95 % CI 45.2-46.3). The steepest rise in seroprevalence still occurred among the subjects aged 25-44 years.     

Declining seroprevalence and transmission of HTLV-I in Japanese families who immigrated to Hawaii

This study examined the seroprevalence and transmission of human T cell lymphotropic virus type I (HTLV-I) in Japanese families who originated in Okinawa, an area in which HTLV-I is endemic, and who were currently residing in Hawaii, a nonendemic area. Among a cohort of Japanese men whose sera were collected in Hawaii in 1967-1975, those of Okinawan ancestry had an HTLV-I seroprevalence of 11.4%. This study, conducted in 1987-1988, sampled 142 index subjects from this male cohort and tested them along with their wives, children, and spouses of the children for HTLV-I antibodies. Seropositivity in their wives was 11.4% and 41.2% among the seronegative and seropositive index subjects, respectively; seropositivity also increased from 29.4% to 35.3% to 58.8% with the husbands' increasing antibody levels by tertiles. Elevated antibody levels may be a marker for infectivity, which is associated with more efficient sexual transmission of HTLV-I. The age-adjusted odds ratio for the association of seropositivity between husband and wife, however, was four times lower than that reported among native Okinawans. In addition, a substantially low seroprevalence (1.3%) was found among their offspring. The decline in HTLV-I transmission in this migrant population may be due to low infectivity in the parent generation who live in a nonendemic environment, increasing numbers of offspring marrying outside of the Okinawan community, and improved living circumstances.