[Detection of Human T lymphotropic virus 1 (HTLV-1) Cosmopolitan subtype Transcontinental subgroup (Aa) and HTLV-2 subtype b in blood donors of Corrientes]

A molecular epidemiological study was conducted in a population of 9422 blood donors in the province of Corrientes, Northeastern Argentina, to determine the prevalence of Human T-cell lymphotropic virus types 1 and 2 (HTLV-1/2), the phylogenetic identification of HTLV-1 and 2 subtypes/subgroups and perform a mutation analysis. Based on the results obtained, it was shown that both HTLV-1 and HTLV-2 are circulating in a low-risk population of Corrientes, although with a similar prevalence to that of non-endemic areas. Phylogenetic studies identified the HTLV-1 Cosmopolitan subtype Transcontinental subgroup (Aa), and the HTLV-2 subtype b. Infected donors reported neither a history of risk factors such as transfusions, intravenous drug use, nor risky or HTLV-1/2 seropositive sexual partners. These results suggest that these viruses were transmitted from mother to child, possibly from generation to generation, and that these strains were introduced into the Caucasian population of this region from ancestors originating from endemic areas of the country either from or through contact with individuals from other countries years ago. Our results demonstrate for the first time the presence of HTLV-1 and HTLV-2 in the province of Corrientes. Moreover, although the province can be considered a non-endemic area, the need to include these retroviruses in a national Public Health program is highlighted, in order to have qualified professionals duly trained to make their diagnosis and provide the necessary information in relation to primary care and patient follow-up.

Hepatitis B, C, and D virus and human T-cell leukemia virus types 1 and 2 infections and correlates among men who have sex with men in Ouagadougou, Burkina Faso

BACKGROUND

Men who have sex with men (MSM) are considered to be at significant risk for sexually transmitted infections (STI) and bloodborne viruses including viral hepatitis types B, C, and D (HBV, HCV, and HDV) and human T-cell leukemia virus types 1 and 2 (HTLV 1&2). This study aimed to assess the seroprevalence and correlates of HBV, HCV, HDV, and HTLV 1&2 antibodies among MSM in Ouagadougou, Burkina Faso.

METHODS

We conducted a cross-sectional survey to assess the biological and behavourial characteristics among MSM in Ouagadougou from January to April 2013. Serum specimens obtained were tested for the presence of HBV, HCV, HDV and HTLV-1&2 infections. MSM 18 years and older were recruited using respondent driven sampling (RDS). Population estimates and 95% confidence intervals (CI) adjusted for the RDS design were calculated using RDS Analysis Tool (RDSAT) version 6.0.1 (RDS, Inc., Ithaca, NY). Bivariate and multivariate logistic regression analyses were conducted to assess correlates of these infections using Stata 14.

RESULTS

A total of 329 MSM were tested. Prevalence was 20.4% (95% CI: 16.4-25.1) for HBV, 11.0% (95% CI: 8.0-14.8) for HCV, and 0.0% for HDV. Anti-HTLV 1&2 antibodies were found in 4.0% (95% CI: 2.3-6.8) of MSM. Factors independently associated with HBV infection were lack of condom use during the last anal sex act with a main male sexual partner and experience of condom tearing during anal sex. Presence of anti-HTLV 1&2 antibodies was associated with history of genital or anal lesions and injection drug use. None of the variables included in our study were associated with HCV.

CONCLUSIONS

This study shows that HBV, HCV and HTLV 1&2 prevalence among MSM in Burkina is high and suggests that comprehensive STI prevention and sexual health education services for this group are needed.

HTLV-1 is rare in Far North Queensland despite a significant burden of classically associated diseases

Human T-lymphotropic virus type 1 (HTLV-1) is hyperendemic amongst Indigenous Australians living in Central Australia. The epidemiology of the disease is poorly defined in other parts of Australia, despite a high prevalence of classically associated conditions. All HTLV-1 serology tests requested through public health facilities in Far North Queensland (FNQ) from January 1999 to December 2016 were reviewed. The person's age, sex, ethnicity, location, rationale for testing and result were recorded. There were 444 tests performed in 409 people; 217 (53%) were male; 171 (42%) identified as Indigenous Australians. Testing increased over time and was performed throughout the region, suggesting increasing awareness of the disease. Testing occurred in patients with haematological, neurological, dermatological and respiratory complaints, but only four (1%) had proven infection. Three of these individuals were in the same family and two were asymptomatic. One of the two symptomatic seropostive individuals had recurrent scabies infection, the other T-cell lymphoma. HTLV-1 infection is extremely uncommon in FNQ. The high rates of bronchiectasis and other associated conditions that are seen in the region are more likely to be addressed by public health policies focusing on the socioeconomic determinants of health.

Estimation of HTLV-1 vertical transmission cases in Brazil per annum

Background

Brazil has at least 800,000 HTLV-1 infected individuals. HTLV-1 can be transmitted via sexual intercourse, contact with blood and from mother to child, mainly by breastfeeding. Treatments for the high morbidity/mortality associated diseases (ATL and HAM/TSP) are limited, therefore, infection prevention is of utmost importance. However, antenatal screening is not routinely performed in Brazil. A lack of data regarding the number of individuals infected via breastfeeding impairs the development of government policies. The objective is to estimate the number of HTLV-1 infections occurring annually due to mother to child transmission (MTCT) in Brazil, nationally and regionally.

Methodology

To estimate HTLV-1 MTCT in Brazil the following variables are modelled: number of births, prevalence of HTLV-1 infection in pregnant women, breastfeeding duration rate and transmission risk according to breastfeeding period. The number of cases of HAM/TSP and ATL attributable to MTCT are also estimated.

Principal findings

In 2008, there were 2,934,828 live births in Brazil. HTLV prevalence in pregnant women in Brazil ranges between 0.1–1.05% by region. An estimated 16,548 HTLV-1 infected women are pregnant each year. According to the breastfeeding pattern and HTLV-1 prevalence of each region there are an estimated 3,024 new cases of HTLV-1 infection due to MTCT annually of which 2,610 are preventable through infant feeding advice. These 3,024 transmissions will result in 120–604 cases of ATL and 8–272 of HAM/TSP. North-East region comprises the high number of MTCT cases, followed by South-East.

Conclusions/significance

A high number of new HTLV-1 infections due to MTCT occur every year in Brazil. Antenatal screening and avoiding breastfeeding are essential to prevent subsequent development of HTLV-1-associated diseases.

The human T-cell lymphotropic virus type 1 (HTLV-1) causes lifelong infection in humans. Although most infected individuals remain asymptomatic HTLV-1 causes severe disease in at least 5% of carriers. In the present study we estimate the number of HTLV-1 infections that occur annually due to mother to child transmission (MTCT) in Brazil and within its regions. The high number of estimated cases due to MTCT (3,024) which will give rise in adult life to HTLV-1associated diseases suggest the importance of performing HTLV-1 antenatal screening in Brazil to reduce the dissemination of this infection and to thus prevent a blood cancer to which most individuals succumb within 8 months of presentation and in others a disabling disease of the spinal cord.

HTLV-1: A real pathogen or a runaway guest of a diseased cell?

The human T-cell lymphotropic virus type 1 (HTLV-1) is a deltaretrovirus claimed to be aetiologically linked to the adult T-cell leukaemia/lymphoma (ATLL) and associated myelopathy/tropical spastic paraparesis (HAM/TSP) besides other minor pathologies. HTLV-1 infection is worldwide distributed, despite its heterogeneous prevalence. Environmental factors and host-genetic background are very likely to determine the epidemiological profile of HTLV-1 prevalence and related disease confinement in distinct human ethnic populations and geographical coordinates, which raises the question if the virus is a real pathogen or a runaway well-organized packed genome of a burden host cell near death process. New methodological approaches need to be proposed and applied in order to prove or discard the hypotheses emerged in the present review.

Low prevalence of HTLV1/2 infection in a population of immigrants living in southern Italy

AIMS

To assess the prevalence of HTLV-1 and HTLV-2 infections in a cohort of immigrants living in southern Italy.

FINDINGS

We screened for antibody to HTLV-1/2 infection 1,498 consecutive immigrants born in endemic areas (sub-Saharan Africa or southern-Asia) by a commercial chemiluminescent microparticle immunoassay. If confirmed in a Western blot assay, which differentiates anti-HTLV-1 from anti-HTLV-2, the positive sera were tested for specific HTLV RNA by a home-made PCR. The immigrants investigated were more frequently males (89.05%), young (median age 26 years), with a low level of education (median schooling 6 years), born in sub-Saharan Africa (79.70%). They had been living in Italy for a median period of 5 months. Only one (0.07%) subject was anti-HTLV-1 -positive/HTLV-1 RNA-negative; he was an asymptomatic 27-year-old male from Nigeria with 6 years' schooling who stated unsafe sexual habits and unsafe injection therapy.

CONCLUSIONS

The data suggest screening for HTLV1 and HTLV-2 infections all blood donors to Italy from endemic countries at least on their first donation; however, a cost-effectiveness study is needed to clarify this topic.

Risk factors associated with HTLV-1 vertical transmission in Brazil: longer breastfeeding, higher maternal proviral load and previous HTLV-1-infected offspring

HTLV-1 is transmitted primarily either through sexual intercourse or from mother to child. The mother/child pairs were classified as seroconcordant or serodiscordant. We analyzed mother to child transmission (MTCT) according to sociodemographic, clinical and epidemiological characteristics of the mother, child's gender and duration of breastfeeding. Between June 2006 and August 2016 we followed 192 mothers with HTLV-1 infection (mean age 41 years old), resulting in 499 exposed offspring, 288 (57.7%) of whom were tested for HTLV-1, making up the final sample for the study, along with their 134 respective mothers. Among the tested mother/child pairs, 41 (14.2%) were HTLV-1 positive, highlighted that seven of 134 family clusters concentrated 48.8% of positive cases. Variables associated with a positive child: breastfeeding duration ≥12 months, maternal PVL ≥100 copies/104 PBMC, mother's age at delivery >26 years old, and HTLV-1 in more than one child of the same mother. In a multiple logistic regression, breastfeeding ≥12 months, higher maternal PVL and ≥2 previous HTLV-1-infected children remained independently associated with the outcome. Thus, high maternal PVL and breastfeeding beyond 12 months were independently associated with MTCT of the HTLV-1 infection. Our results reinforce the need for both prenatal HTLV screening in endemic areas and for advising mothers on breastfeeding.

Stability of the HTLV-1 glycoprotein 46 (gp46) gene in an endemic region of the Brazilian Amazon and the presence of a significant mutation (N93D) in symptomatic patients

BACKGROUND

The human T-lymphotropic virus type 1 (HTLV-1) affects 2-5 million people worldwide, and is associated with a number of degenerative and infectious diseases. The Envelope glycoproteins (gp) are highly conserved among the different HTLV-1 isolates, although nucleotide substitutions in the region that codifies these proteins may influence both the infectivity and the replication of the virus. The gp46 gene has functional domains which have been associated with the inhibition of the formation of the syncytium, cell-cell transmission, and the production of antibodies. The present study investigated the genetic stability of the gp46 gene of HTLV-1 in an endemic region of Brazilian Amazonia.

METHODS

Index case (IC - a sample of a given family group) carriers of HTLV-1 were investigated in the metropolitan region of Belém (Pará, Brazil) between January 2010 (registered retrospectively) and December 2015. The sequences that codify the gp46 were amplified by PCR, purified and sequenced (MF084788-MF084825). The gene was characterized using bioinformatics and Bayesian Inference.

RESULTS

The 40 patients analyzed had a mean age of 45.2 years and 70% presented some type of symptom, with a predominance of pain and sensitivity, dysautonomia, and motor disorders. All patients presented the aA (Transcontinental Cosmopolitan) genotype, with an extremely low mutation rate, which is characteristic of the codifying region (aA - 1.83 × 10-4 mutations per site per year). The gp46 gene had a nucleotide diversity of between 0.00% and 2.0%. Amino acid mutations were present in 66.6% of the samples of individuals with signs/symptoms or diseases associated with HTLV-1 (p = 0.0091). Of the three most frequent mutations, the previously undescribed N93D mutant was invariably associated with symptomatic cases.

CONCLUSIONS

The aA HTLV-1 subtype is predominant in the metropolitan region of Belém and presented a high degree of genetic stability in the codifying region. The rare N93D amino acid mutation may be associated with the clinical manifestations of this viral infection.

IMPORTANCE

Little is known of the phylogeny of HTLV-1 in the endemic region of Brazilian Amazonia, and few complete gene sequences are available for the gp46 glycoprotein from the local population. The nucleotide sequences of the viral gp46 gene recorded in the present study confirmed the genetic stability of the region, and pointed to a homogeneous viral group, with local geographic characteristics. Further research will be necessary to more fully understand the molecular diversity of this protein, given the potential of this codifying region as a model for an effective HTLV-1 vaccine. The identification of a rare mutation (N93D), present only in symptomatic patients, should also be investigated further as a potential clinical marker.

TRIAL REGISTRATION

ISRCTN 12345678, registered 28 September 2014.

Temporal trends in Human T-Lymphotropic virus 1 (HTLV-1) associated myelopathy/tropical spastic paraparesis (HAM/TSP) incidence in Martinique over 25 years (1986-2010)

BACKGROUND

Human T-lymphotropic virus type 1 (HTLV-1) has been discovered in 1980 and has been linked to tropical spastic paraparesis (HAM/TSP) in 1985 in Martinique. There is no data on HAM/TSP incidence trends. We report, in the present work, the temporal trends incidence of HAM/TSP in Martinique over 25 years.

METHODS

Martinique is a Caribbean French West Indies island deserved by a unique Neurology Department involved in HAM/TSP diagnosis and management. A registry has been set up since 1986 and patients diagnosed for a HAM/TSP were prospectively registered. Only patients with a definite HAM/TSP onset between 1986 and 2010 were included in the present study. The 25-year study time was stratified in five-year periods. Crude incidence rates with 95% confidence interval (95%CI) were calculated using Poisson distribution for each period. Age-standardized rates were calculated using the direct method and the Martinique population census of 1990 as reference. Standardized incidence rate ratios with 95% CIs and P trends were assessed from simple Poisson regression models. Number of HTLV-1 infection among first-time blood donors was retrospectively collected from the central computer data system of the Martinique blood bank. The HTLV-1 seroprevalence into this population has been calculated for four 5-year periods between 1996 and 2015.

RESULTS

Overall, 153 patients were identified (mean age at onset, 53+/-13.1 years; female:male ratio, 4:1). Crude HAM/TSP incidence rates per 100,000 per 5 years (95%CI) in 1986-1990, 1991-1995, 1996-2000, 2001-2005 and 2006-2010 periods were 10.01 (6.78-13.28), 13.02 (9.34-16.70), 11.54 (8.13-14.95), 4.27 (2.24-6.28) and 2.03 (0.62-3.43). Age-standardized 5-year incidence rates significantly decreased by 69% and 87% in 2001-2005 and 2006-2010 study periods. Patients characteristics did not differ regarding 1986-2000 and 2001-2010 onset periods. Between 1996-2000 and 2011-2015 study periods, the HTLV-1 seroprevalence significantly decreased by 63%.

CONCLUSION

Martinique faces a sudden and rapid decline of HAM/TSP incidence from 2001 in comparison to 1986-2000 periods. Reduction of HTLV-1 seroprevalence, that may result from transmission prevention strategy, could account for HAM/TSP incidence decrease.

Human T-Lymphotropic Virus type 1c subtype proviral loads, chronic lung disease and survival in a prospective cohort of Indigenous Australians

Background

The Human T-Lymphotropic Virus type 1c subtype (HTLV-1c) is highly endemic to central Australia where the most frequent complication of HTLV-1 infection in Indigenous Australians is bronchiectasis. We carried out a prospective study to quantify the prognosis of HTLV-1c infection and chronic lung disease and the risk of death according to the HTLV-1c proviral load (pVL).

Methodology/Principal findings

840 Indigenous adults (discharge diagnosis of bronchiectasis, 154) were recruited to a hospital-based prospective cohort. Baseline HTLV-1c pVL were determined and the results of chest computed tomography and clinical details reviewed. The odds of an association between HTLV-1 infection and bronchiectasis or bronchitis/bronchiolitis were calculated, and the impact of HTLV-1c pVL on the risk of death was measured.

Radiologically defined bronchiectasis and bronchitis/bronchiolitis were significantly more common among HTLV-1-infected subjects (adjusted odds ratio = 2.9; 95% CI, 2.0, 4.3). Median HTLV-1c pVL for subjects with airways inflammation was 16-fold higher than that of asymptomatic subjects. There were 151 deaths during 2,140 person-years of follow-up (maximum follow-up 8.13 years). Mortality rates were higher among subjects with HTLV-1c pVL ≥1000 copies per 10⁵ peripheral blood leukocytes (log-rank χ² (2df) = 6.63, p = 0.036) compared to those with lower HTLV-1c pVL or uninfected subjects. Excess mortality was largely due to bronchiectasis-related deaths (adjusted HR 4.31; 95% CI, 1.78, 10.42 versus uninfected).

Conclusion/Significance

Higher HTLV-1c pVL was strongly associated with radiologically defined airways inflammation and with death due to complications of bronchiectasis. An increased risk of death due to an HTLV-1 associated inflammatory disease has not been demonstrated previously. Our findings indicate that mortality associated with HTLV-1c infection may be higher than has been previously appreciated. Further prospective studies are needed to determine whether these results can be generalized to other HTLV-1 endemic areas.

The Human T-Lymphotropic Virus type 1 (HTLV-1) infects up to 20 million people worldwide who predominantly reside in resource-limited areas. The virus is associated with a haematological malignancy (adult T-cell leukaemia/lymphoma, ATL), and inflammatory diseases involving organ systems including the spinal cord, eyes and lungs. Determining the outcomes of infection in most HTLV-1 endemic areas is extremely difficult; however, the virus is highly endemic to central Australia where the Indigenous population has access to sophisticated medical facilities. We prospectively followed a large hospital-based cohort of Indigenous Australian adults that was well characterized with regard to base-line comorbid conditions, HTLV-1 serostatus and HTLV-1 proviral load (pVL). A higher baseline HTLV-1 pVL was strongly associated with an increased risk of airway inflammation (bronchitis/bronchiolitis and bronchiectasis) and death, which most often resulted from complications of bronchiectasis. Increased mortality due to an HTLV-1-associated inflammatory condition has not been demonstrated previously. The morbidity and mortality associated with HTLV-1 infection may therefore be substantially higher than has been assumed from an analysis of cohorts of subjects with adult T-cell leukaemia or HTLV-1-associated myelopathy. These findings have important implications for epidemiological research and for determining health care priorities in resource-limited settings.

Evaluation of Line Immunoassay to Detect HTLV-1 Infection in an Endemic Area, Southwestern Japan; Comparison with Polymerase Chain Reaction and Western Blot

BACKGROUND

Human T-lymphotropic virus type 1 (HTLV-1) has been recognized as a cause of adult T-cell leukemia/lymphoma, HTLV-1-associated myelopathy/tropical spastic paraparesis, and HTLV-1-associated uveitis. HTLV-1 infection is normally detected by screening for HTLV-1 antibodies, and positive samples are confirmed by Western blot (WB). However, WB fails to confirm some samples that were positive for HTLV-1 antibodies on screening. Line immunoassay (LIA) is commonly used in Europe and Brazil, but not in Japan. Therefore, we evaluated the performance of LIA as a method of confirming HTLV-1 antibodies using samples in Japan.

METHODS

LIA was compared with polymerase chain reaction (PCR) and WB using 50 negative and 70 positive samples tested by chemiluminescent enzyme immunoassay (CLEIA) in Miyazaki, Japan, an HTLV-1 endemic area. LIA (INNO-LIA HTLVI/II Score) and WB (Problot HTLV-I) were performed according to the manufacturer's instructions. Real-time PCR for HTLV-1 pX region was performed using DNA derived from white blood cells. The samples that tested negative by real-time PCR were further tested by nested PCR.

RESULTS

All 50 CLEIA negative samples were determined to be negative by LIA and PCR. Of the 70 positive samples, 66 tested positive by both of LIA and PCR. Three samples tested negative by LIA and PCR, and the remaining sample (PCR negative) showed non-specific staining in LIA and WB. WB showed more indeterminate results than LIA. Gp21 antibody in LIA demonstrated a high ability to discriminate between positive and negative PCR results. Furthermore, the degree of gp21 antibody reaction by LIA showed correlation with HTLV-1 proviral loads (PVLs).

CONCLUSIONS

Our results indicate that LIA performs well in confirming HTLV-1 seropositivity by showing a low incidence of indeterminate results and good agreement with PCR using samples in Japan, although the number of samples tested was small. In addition, semi-quantitative antibody titer to gp21 correlated well with HTLV-1 PVLs. Further study including larger samples is necessary to determine the positioning of LIA for HTLV-1 detection in Japan.

Cytokine profile and proviral load among Japanese immigrants and non-Japanese infected with HTLV-1 in a non-endemic area of Brazil

The lifetime risk of HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) development differs among ethnic groups. To better understand these differences, this prospective cohort study was conducted to investigate the cytokine profile and the HTLV-1 proviral load (PVL) in Japanese and non-Japanese populations with HAM/TSP and asymptomatic carriers (ACs). The serum IL-2, IL-4, IL-6, IL-10, IL-17, TNF-α, and IFN-γ levels were quantified using the Cytometric Bead Array in 40 HTLV-1-infected patients (11 HAM/TSP and 29 ACs) and 18 healthy controls (HCs) in Brazil. Among ACs, 15 were Japanese descendants and 14 were non-Japanese. Of 11 patients with HAM/TSP, only one was a Japanese descendant. The HTLV-1 PVL was quantified by real-time PCR. The HTLV-1 PVL was 2.7-fold higher in HAM/TSP patients than ACs. Regardless of the clinical outcome, the PVL was significantly higher in patients younger than 60 years than older patients. The HAM/TSP and ACs had higher IL-10 serum concentrations than that of HCs. The ACs also showed higher IL-6 serum levels than those of HCs. According to age, the IL-10 and IL-6 levels were higher in ACs non-Japanese patients older than 60 years. HAM/TSP patients showed a positive correlation between IL-6 and IL-17 and a negative correlation between the PVL and IL-17 and IFN-γ. In the all ACs, a significant positive correlation was observed between IL-2 and IL-17 and a negative correlation was detected between IL-10 and TNF-α. Only 6.25% of the Japanese patients were symptomatic carriers, compared with 41.67% of the non-Japanese patients. In conclusion, this study showed that high levels of HTLV-1 PVL was intrinsicaly associated with the development of HAM/TSP. A higher HTLV-1 PVL and IL10 levels found in non-Japanese ACs over 60 years old, which compared with the Japanese group depicts that the ethnic background may interfere in the host immune status. More researches also need to be undertaken regarding the host genetic background to better understand the low frequency of HAM/TSP in Japanese HTLV-1-infected individuals.

Hepatitis B virus and human T-cell lymphotropic virus type 1 co-infection in the Northern Territory, Australia

OBJECTIVE

To establish the relationship between hepatitis B virus (HBV) and human T-cell lymphotropic virus type 1 (HTLV-1) serological markers in the Northern Territory, Australia.

METHODS

A retrospective serological study of patients presenting to public healthcare facilities in the Northern Territory between 2008 and 2015 was performed in order to determine the presence and relationships of serological markers of HBV and HTLV-1.

RESULTS

Seven hundred and forty individual patients were found to be serologically positive for HTLV-1 in the Northern Territory over the 8-year period. Hepatitis B results were available for 521 of these patients. Hepatitis B surface antigen (HBsAg) positivity was demonstrated in 15.9% (83/521) of this cohort, which was significantly different to the HTLV-1-negative group (3.7%, 125/3354) (p<0.001). Excluding individuals with isolated hepatitis B surface antibody (anti-HBs), those in the HTLV-1-positive group had a higher HBV exposure history (67.5%, 352/521) when compared to HTLV-1-negative individuals (37.8%, 1259/3354) (p<0.001). HTLV-1-positive individuals had a lower prevalence of HBV combined anti-HBs and hepatitis B core antibody (anti-HBc) positive markers compared to those who were HTLV-1-negative (56.3% (198/352) versus 73.8% (937/1269), respectively; p<0.001).

CONCLUSIONS

A significantly higher prevalence rate of HBV was found in HTLV-1-positive individuals from the Northern Territory. When considering the higher exposure to HBV in HTLV-1-positive individuals, the clearance of HBV appears lower than in those individuals testing HTLV-1-negative. A lower prevalence of clearance in HTVL-1-positive individuals than in HTLV-1-negative individuals, as signified by formation of HBVcAb and HBVsAb in HTVL-1 positive individual's may equate to higher prevalence of ongoing coinfection.

HTLV-1 is predominantly sexually transmitted in Salvador, the city with the highest HTLV-1 prevalence in Brazil

Background

Salvador is the city with the highest number of HTLV-1 infected individuals in Brazil, yet the main route of HTLV-1 transmission is unknown.

Objective

To investigate the association of syphilis infection as a proxy for sexual transmission of HTLV-1 infection in the general population of this city.

Methods

A cross sectional population-based study was conducted with 3,451 serum samples obtained by a representative simple random sampling. Data on gender, age, income, and years of education were collected by questionnaire and the presence of HTLV, HIV and Treponema pallidum infection was determined by serology. Logistic regression analysis was used to evaluate the independent effect of the potential explanatory variables to HTLV-1 infection and Odds Ratios (OR) and 95% CI were calculated.

Results

The majority of studied individuals were female (56.4%), had less than 7 years of education (55.3%) and earned two or less minimum wages (52.0%). The overall prevalence of HTLV-1 was 1.48% (51/3,451; 95% CI: 1.10%– 1.94%), which increased with age. Only three persons younger than 17 (3/958; 0.31%; CI 95% 0.06–0.91) years were infected by HTLV-1. Among the 45 syphilis positives, 12 (26.7%) were HTLV positive, while among 21 HIV positives, only one (4.8%) was HTLV positive. HTLV-1 infection was found to be associated with syphilis infection (OR_ADJUSTED 36.77; 95% CI 14.96–90.41).

Conclusion

The data presented herein indicate that horizontal transmission between adults is the main route of HTLV-1 infection in the general population of Salvador and that this is likely to occur through sexual contact.

A Novel Human T-lymphotropic Virus Type 1c Molecular Variant in an Indigenous Individual from New Caledonia, Melanesia

BACKGROUND

Human T-Lymphotropic Virus type 1 (HTLV-1) is endemic among people of Melanesian descent in Papua New Guinea, Solomon Islands and Vanuatu, and in Indigenous populations from Central Australia. Molecular studies revealed that these Australo-Melanesian strains constitute the highly divergent HTLV-1c subtype. New Caledonia is a French overseas territory located in the Southwest Pacific Ocean. HTLV-1 situation is poorly documented in New Caledonia and the molecular epidemiology of HTLV-1 infection remains unknown.

OBJECTIVES

Studying 500 older adults Melanesian natives from New Caledonia, we aim to evaluate the HTLV-1 seroprevalence and to molecularly characterize HTLV-1 proviral strains.

STUDY DESIGN

Plasma from 262 men and 238 females (age range: 60-96 years old, mean age: 70.5) were screened for anti-HTLV-1 antibodies by particle agglutination (PA) and indirect immunofluorescence assay (IFA). Serological confirmation was obtained using Western blot assay. DNAs were extracted from peripheral blood buffy coat of HTLV-1 seropositive individuals, and subjected to four series of PCR (LTR-gag; pro-pol; pol-env and tax-LTR). Primers were designed from highly common conserved regions of the major HTLV-1 subtypes to characterize the entire HTLV-1 proviral genome.

RESULTS

Among 500 samples, 3 were PA and IFA positive. The overall seroprevalence was 0.6%. The DNA sample from 1 New Caledonian woman (NCP201) was found positive by PCR and the complete HTLV-1 proviral genome (9,033-bp) was obtained. The full-length HTLV-1 genomic sequence from a native woman from Vanuatu (EM5), obtained in the frame of our previous studies, was also characterized. Both sequences belonged to the HTLV-1c Australo-Melanesian subtype. The NCP201 strain exhibited 0.3% nucleotide divergence with the EM5 strain from Vanuatu. Furthermore, divergence reached 1.1% to 2.9% with the Solomon and Australian sequences respectively. Phylogenetic analyses on a 522-bp-long fragment of the gp21-env gene showed the existence of two major clades. The first is composed of strains from Papua New Guinea; the second includes strains from all neighboring archipelagos (Solomon, Vanuatu, New Caledonia), and Australia. Interestingly, this second clade itself is divided into two sub-clades: strains from Australia on one hand, and strains from Solomon Islands, Vanuatu and New Caledonia on the other hand.

CONCLUSIONS

The HTLV-1 seroprevalence (0.6%) in the studied adult population from New Caledonia appears to be low. This seroprevalence is quite similar to the situation observed in Vanuatu and Solomon Islands. However it is very different to the one encountered in Central Australia. Taken together, these results demonstrated that Australo-Melanesia is endemic for HTLV-1 infection with a high diversity of HTLV-1c strains and a clear geographic clustering according to the island of origin of HTLV-1 infected persons.

Endemic impact of human T cell leukemia virus type 1 screening in bone allografts

Allograft bone is a widely used as a convenient tool for reconstructing massive bone defects in orthopedic surgery. However, allografts are associated with the risk of viral disease transmission. One of the viruses transmitted in this manner is human T-lymphotropic virus type 1 (HTLV-1), which is found worldwide but is unevenly distributed. The southwestern parts of Japan are a highly endemic for HTLV-1. We investigated the HTLV-1 seroprevalence in candidate allograft donors at the regional bone bank in Kagoshima, Japan during its first 5 years of service. Between 2008 and 2012, we collected 282 femoral heads at the Kagoshima regional bone bank from living donors with osteoarthritis of the hip joint. Among the 282 candidate donors, 32 donors (11.3 %) were seropositive for anti-HTLV-1 antibody; notably, this prevalence is higher than that reported for blood donors in this area. Additionally, to determine if HTLV-1 genes are detectable after processing, we examined the bone marrow of the femoral heads from seropositive donors by conducting PCR assays. Our results confirm the existence of viral genes following the heat treatment processing of the femoral heads. Therefore, it is important to inactivate a virus completely by heat-treatment. Together, our findings highlight the importance of HTLV-1 screening at bone banks, particularly in HTLV-1-endemic areas such as southwest Japan.

Incidence of human T-lymphotropic virus 1 infection in adolescent and adult blood donors in Japan: a nationwide retrospective cohort analysis

BACKGROUND

Human T-lymphotropic virus 1 (HTLV-1) infection has an especially high prevalence in Japan. Transmission has been confirmed in infancy through breastfeeding; however, little is known about the epidemiological aspects of new HTLV-1 infections later in life. We aimed to estimate the nationwide annual number of new HTLV-1 infections among adolescents and adults in Japan.

METHODS

In this retrospective cohort analysis, we assessed new HTLV-1 infections of repeat blood donors aged 16-69 years between Jan 1, 2005, and Dec 31, 2006, in the Japanese Red Cross Blood Centres database. We used results of antibody tests done in repeat blood samples collected until Dec 31, 2011, to assess the number who seroconverted to HTLV-1. We calculated the incidence density by dividing the number of seroconverters by the number of person-years of follow-up, and then extrapolated densities to regional populations to estimate the annual number of new HTLV-1 infections.

FINDINGS

We included 3 375 821 HTLV-1-seronegative blood donors (2 100 915 men and 1 274 906 women). Within a median follow-up of 4·5 years (IQR 2·3-5·8), 532 people (204 men and 328 women) had seroconverted. The incidence density was significantly higher in women (6·88 per 100 000 person-years; 95% CI 6·17-7·66) than in men (2·29 per 100 000 person-years; 95% CI 1·99-2·62; p<0·0001). The estimated annual number of new HTLV-1 infections was 4190 (95% CI 4064-4318) with 975 (914-1038) infections in men and 3215 (3104-3328) in women.

INTERPRETATION

New HTLV-1 infections in adolescents and adults are an important public health concern in Japan and preventive strategies are needed to reduce new transmission.

FUNDING

Ministry of Health, Labour, and Welfare of Japan; Japan Agency for Medical Research and Development.

Epidemic History and Iatrogenic Transmission of Blood-borne Viruses in Mid-20th Century Kinshasa

BACKGROUND

The human immunodeficiency virus type 1 (HIV-1) pandemic was ignited in Léopoldville (now known as Kinshasa), in the former Belgian Congo. Factors that jump-started its early expansion remain unclear. Nonlethal hepatitis C virus (HCV) and human T-cell lymphotropic virus (HTLV-1) can be used to investigate past iatrogenic transmission.

METHODS

We undertook a cross-sectional study of elderly inhabitants of Kinshasa, with serological assays, amplification, and sequencing. Risk factors were assessed through logistic regression. Phylogenetic methods reconstructed the genetic history of HCV.

RESULTS

A total of 217 of 839 participants (25.9%) were HCV seropositive; 26 (3.1%) were HTLV-1-seropositive. Amplification products were obtained from 118 HCV-seropositive participants; subtypes 4k (in 47 participants) and 4r (in 38) were most common. Independent risk factors for HCV subtype 4r seropositivity were intramuscular tuberculosis therapy, intravenous injections at hospital A, intravenous injections before 1960, and injections at a colonial-era venereology clinic. Intravenous injections at hospital B and antimalarials were associated with HCV subtype 4k seropositivity. Risk factors for HTLV-1 seropositivity included intravenous injections at hospitals C or D and transfusions. Evolutionary analysis of viral sequences revealed independent exponential amplification of HCV subtypes 4r and 4k from the 1950s onward.

CONCLUSIONS

Iatrogenic transmission of HCV and HTLV-1 occurred in mid-20th century Kinshasa, at the same time and place HIV-1 emerged. Iatrogenic routes may have contributed to the early establishment of the pandemic.

TOXOPLASMA AND VIRAL ANTIBODIES AMONG HIV PATIENTS AND INMATES IN CENTRAL JAVA, INDONESIA

In Indonesia, Toxoplasma and its associations with blood-borne viruses have been poorly studied. In order to study the association between anti-Toxoplasma antibodies and blood-borne viral antibodies, blood samples from 497 participants (375 inmates from four prisons in Central Java, Indonesia and 122 HIV patients at a Voluntary Counseling and Testing Clinic in Surakarta, Indonesia) were tested for serological markers of Toxoplasma, human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis D virus (HDV) and human T-lymphotropic virus types I and II (HTLV-1/2). Anti-Toxoplasma IgG and IgM positivity rates were 41.6% and 3.6%, respectively. One point two percent of participants was positive for both anti-Toxoplasma IgG and IgM antibodies. Sixteen point five percent, 11.3%, 2.6% and 2.8% of participants were positive for anti- Toxoplasma IgG combined with anti-HCV antibodies, anti-Toxoplasma IgG combined with anti-HIV antibodies, anti-Toxoplasma IgM combined with anti-HIV antibodes and anti-Toxoplasma IgG combined with both anti-HIV and anti-HCV antibodies, respectively. Anti-Toxoplasma IgM seropositivity was associated with anti-HIV (aOR = 4.3; 95% CI: 1.112-16.204, p = 0.034). Anti-Toxoplasma IgG antibodies were associated with anti-HCV (aOR = 2.8; 95% CI: 1.749-4.538, p < 0.001) and history of injection drug use (aOR = 3.1; 95% CI: 1.905-5.093, p < 0.001). In conclusion, we recommend patients with HIV, HCV infection and injection drug users should be screened for Toxoplasma infection in Indonesia.

Incidence of adult T-cell leukemia/lymphoma in nonendemic areas

Adult T-cell leukemia/lymphoma (ATLL) is a mature T-cell neoplasm with extremely poor prognosis caused by human T-cell leukemia virus type 1 (HTLV-1). The distribution of HTLV-1 and the incidence of ATLL in endemic areas have been well described, however, little is known about the incidences and the trends of the disease in nonendemic areas. Recently, studies have shown that the HTLV-1 carriers are increasing in nonendemic areas. Also, the incidence of ATLL seems to be significantly increasing in nonendemic areas suggesting that HTLV-1 carriers have emigrated from endemic areas. These epidemiologic studies indicate the necessity of edification of the disease caused by HTLV-1 and establishing appropriate preventive methods against infection in nonendemic areas.

The Burden of Neglected HIV-2 and HTLV-1 Infections in Spain

HIV-2 and HTLV-1 infections are globally less frequent than those produced by HIV-1, the classical AIDS agent. In Spain and up to the end of 2014, a total of 310 cases of HIV-2, 274 of HTLV-1, and 776 of HTLV-2 infections had been reported. No cases of HTLV-3 or HTLV-4 infections have been identified so far in Spain. Most persons infected with HIV-2 or HTLV-1 acknowledge epidemiological risk factors for contagion, such as originating from or living in endemic regions and/or having had sexual partners from those areas. However, risk factors could not be recognized in up to 20-25% of carriers in Spain. Thus, it seems worth keeping a high level of clinical suspicion in order to identify earlier these neglected human retroviral infections, since diagnostic procedures and antiviral treatment are specific for each of these agents. In this article we summarize the major contributions reported at the meeting of the Spanish Group for HIV-2/HTLV held in Madrid in December 2014.

High prevalence of HTLV-1 infection among Japanese immigrants in non-endemic area of Brazil

Background

Human T-lymphotropic virus type 1 (HTLV-1) has worldwide distribution and is considered endemic in many world regions, including southwestern Japan and Brazil. Japanese immigrants and their descendants have a high risk of acquiring this infection due to intense population exchange between Brazil and Japan.

Objective

This cross-sectional study aimed to estimate the prevalence of HTLV, analyze the main risk factors associated with this infection, identify the main circulating types and subtypes of HTLV in Japanese immigrants and descendants living in Campo Grande-MS (Middle-West Brazil), as well as analyze the phylogenetic relationship among isolates of HTLV.

Study Design

A total of 219 individuals were interviewed and submitted to blood collection. All collected blood samples were submitted for detection of anti-HTLV-1/2 using the immunoassay ELISA and confirmed by immunoblot method. The proviral DNA of the 14 samples HTLV- 1 positive were genotyped by nucleotide sequencing.

Results

The overall prevalence of HTLV-1 was 6.8% (IC 95%: 3,5-10,2). Descriptive analysis of behavioral risk factors showed statistical association between HTLV-1 and age greater than or equal to 45 years. The proviral DNA of HTLV-1 was detected in all HTLV-1 positive samples. Of these, 14 were sequenced and classified as Cosmopolitan subtype, and 50% (7/14) belonged to subgroup A (transcontinental) and 50% (7/14) to the subgroup B (Japanese).

Conclusion

The high prevalence of HTLV-1 found evidence of the importance of early diagnosis and counseling of individuals infected with HTLV-1 for the control and prevention of the spread of this infection among Japanese immigrants and their descendants in Central Brazil.

The population of Okinawan immigrants is considered vulnerable to human T-lymphotropic virus type 1 (HTLV-1) infection because the Okinawa region in Japan is an endemic area. The second Brazilian largest Okinawan community is set in Campo Grande, Middle-West Brazil. This study aimed to estimate the prevalence and risk factors associated with HTLV infection among Japanese immigrants and their descendants living in Campo Grande. The prevalence of 6.8% of HTLV-1 infection that was found is considered high. The HTLV-1 infection was associated with age ranged from 45 years old or older. Most infected individuals are Okinawan descendants. The HTLV-1 rate found in the present study indicates that the prevalence of this infection remains high among this Japanese community. This study emphasizes the importance of implementing preventive and diagnostic public health policies to decrease the risk of HTLV-1 transmission among Japanese communities throughout Brazil.