Sero-epidemiologic and phylogenetic studies of HTLV-I infection in 2 countries of the Caspian Sea region

Clinical and Public Health Implications of Human T-Lymphotropic Virus Type 1 Infection

Human T-lymphotropic virus type 1 (HTLV-1) is estimated to affect 5 to 10 million people globally and can cause severe and potentially fatal disease, including adult T-cell leukemia/lymphoma (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). The burden of HTLV-1 infection appears to be geographically concentrated, with high prevalence in discrete regions and populations. While most high-income countries have introduced HTLV-1 screening of blood donations, few other public health measures have been implemented to prevent infection or its consequences. Recent advocacy from concerned researchers, clinicians, and community members has emphasized the potential for improved prevention and management of HTLV-1 infection. Despite all that has been learned in the 4 decades following the discovery of HTLV-1, gaps in knowledge across clinical and public health aspects persist, impeding optimal control and prevention, as well as the development of policies and guidelines. Awareness of HTLV-1 among health care providers, communities, and affected individuals remains limited, even in countries of endemicity. This review provides a comprehensive overview on HTLV-1 epidemiology and on clinical and public health and highlights key areas for further research and collaboration to advance the health of people with and at risk of HTLV-1 infection.

Epidemiology of blood-borne viral infections in Afghanistan

Although a few studies have been done on transmissible blood-borne viral infections in high-risk groups, little attention has been given to assessing the infection status of the general population in Afghanistan. To investigate the epidemiological status in the general population, we tested the serological markers of hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis delta virus (HDV), human immunodeficiency virus 1 (HIV-1) and human T-cell leukemia virus (HTLV) infections. In total, 492 samples were selected randomly from Nangarhar, Herat, Mazar-e Sharif, Kandahar, and Kabul from subjects between 25 and 70 years old. The samples were tested for the presence of HBsAg, anti-HBs, anti-HBc, anti-HDV, anti-HCV, anti-HIV-1 and anti-HTLV I/II antibodies using chemiluminescent immunoassays on Abbott Architect automated platforms. In addition, 220 HBsAg-positive samples identified among 5897 samples from the general population of the same regions of Afghanistan were included in the study and tested for both HBsAg and anti-HDV to investigate HDV prevalence in the country. Viral loads of HBV, HCV and HDV were determined in all seropositive samples using Ampliprep/Cobas TaqMan HBV, HCV, Test Roche (CA, USA), and an in-house method, respectively. Out of 492 samples, 31 (6.3%), 136 (27.6%) and 149 (30.3%) were found to be positive for HBsAg, anti-HBs and anti-HBc, respectively. Anti-HDV positivity was detected in five (2.1%) out of 234 HBsAg-positive samples (including 14 of the randomly selected samples that were not among the 220 previously identified as HBsAg positive). Only eight out of 492 (1.6%) subjects were positive for anti-HCV antibodies. Seven out of 489 (1.4%) were positive for anti-HIV-1 antibodies, and three out of 466 cases (0.6%) were positive for anti-HTLV I/II antibodies. These results suggest that Afghanistan is an intermediate endemic region for HBV, HDV and HCV infection. The prevalence of HIV-1 seems to be significantly higher than the global prevalence and that of the eastern Mediterranean region. In addition, the HTLV I/II screening results suggest that these viruses should be monitored in Afghanistan to confirm the trend observed in the current study.

Phylogenetic analysis of HTLV-1 in Iranian blood donors, HIV-1 positive patients and patients with beta thalassemia

Human T-cell lymphoma virus (HTLV) has been associated with various disease types. Since the discovery of the virus in 1980, seven subtypes of the virus have been identified. HTLV is widespread and endemic in some regions, such as Japan, Africa, South America, and northeast Iran. This study aimed to identify HTLV-1 genotype and also to analyze the nucleotide sequence of the LTR region in three groups, including blood donors, HIV-1+ patients, and β-thalassemia patients. In this cross-sectional study, 2200 samples were collected from blood donors in Tehran (2000 samples), HIV-1+ patients (100 samples) and β-thalassemia patients (100 samples). All samples were screened for anti-HTLV-I&II antibodies by ELISA. Then, genomic DNA was extracted from repeatedly positive samples, and nested PCR was performed for both the TAX and LTR regions. Purified PCR products were sequenced and analyzed, and finally, a phylogenetic tree was constructed using Mega7 software. The prevalence of the anti-HTLV-I&II antibody among blood donors and HIV-1+ patients was 1.7% (34/2000) and 12% (12/100), respectively. The PCR results confirmed that 0.05% (1/2000) of blood donors, 5% (5/100) of HIV-1+ patients, and 8% (8/100) of β-thalassemia patients were HTLV-I positive. All sequences were matched to HTLV-1 subtype a, subgroup A. Our phylogenetic analysis revealed that all sequenced samples belong to the endemic clusters of Iran. HTLV-1 genotypes in all samples were similar in three groups and were derived from the strains, which had been previously reported from Iran (AF00300/Mashhad and KT190712.1/Sabzevar).

Seroprevalence and geographical distribution of human T-lymphotropic virus type 1 among volunteer blood donors in endemic areas of Iran

Background

Human T-cell lymphotrophic virus type 1 (HTLV-1) has a worldwide distribution and it is endemic in some regions of Iran. One of the most important routes of HTLV-1 transmission is via transfusion of contaminated blood components. The risk of transmission through asymptomatic blood donors, particularly in endemic areas should be considered and appropriately managed. The main objective of this study was to determine the seroprevalence and description the geographic distribution of HTLV-1 among voluntary blood donors in Iran.

Methods

This retrospective study carried out using the data obtained from the main database of the seven blood transfusion centers of Iranian Blood Transfusion Organization between 2009 and 2013. The presence of anti-HTLV-1/2 antibodies were primarily assessed using Enzyme-linked Immunosorbent Assay. The Ab Kit assay, contain antigens for the screening of antibodies to HTLV type 1 and 2. So, it is expressed as HTLV 1/2 assay. Samples that were positive by the western blot confirmatory test were considered as definite positive HTLV-1 or HTLV-2 cases. The main socio-demographic variables were; age, gender, donation history and marital status. Descriptive and analytical statistics were used to summarize the gathered data. The chi-Square Statistical test was used to test the association between groups, P-value of less than 0.05 was considered significant.

Results

A total of 1864489 blood donations were evaluated. There were 1840 confirmed HTLV-1 positive donations (0.098%). None were positive for anti-HTLV-2. The overall HTLV-1 prevalence was 98.7 per 100,000 donations during the 5 year period. Seroprevalence was higher among females, married and older blood donors. The overall seropositivity among first time, regular and lapsed donors was, 0.29% (290/100000), 0.001% (1/100000) and 0.02% (20/100000) respectively. A significant difference was observed between regular and the first time (p <0.0001) and also between lapsed and regular blood donors (p <0.0001). Most of the HTLV-1 seropositive blood donors (175 per 100,000) were from northeastern regions. We observed a gradual decline in overall HTLV-1 prevalence during the course of the study, the prevalence rate decreased from 0.13% (130/100000) in 2009 to 0.07% (70/100000) in 2013.

Conclusions

The Seroprevalence of HTLV-1 among Iranian blood donors in the regions of our study still is considerable, but there is an obvious declining prevalence over the course of present study. Blood transfusion centers should continually evaluate the residual risk of infection in the country, especially in endemic areas.

Seroepidemiology of HTLV-1 and HTLV-2 Infection in Neyshabur City, North-Eastern Iran, during 2010-2014

BACKGROUND

Retroviruses of human T-lymphotropic viruses (HTLV-1 and HTLV-2) have been demonstrated to be endemic in the north-eastern region of Iran. This study was aimed to determine the HTLV-1 and HTLV-2 prevalence among healthy individuals in Neyshabur City during 2010-2014.

METHODS

A total of 8054 blood samples were collected from healthy participants in Neyshabur, North-Eastern Iran. The blood samples were screened for the presence of specific antibodies against HTLV-1 and HTLV-2 by using ELISA according to the manufacturer's instructions.

RESULTS

The overall seropositivity rate for HTLV-1 and HTLV-2 was found to be 6.55% (528 out of 8054) among participants.

CONCLUSION

Both HTLV-1 and HTLV-2 were demonstrated to be at a high rate in healthy individuals. However, a smaller number of asymptomatic carriers were found in this study, as compared to those identified in previous investigations in the city.

Seroepidemiology of human T-cell lymphotropic virus type-I in blood donors of Northeastern Iran, Sabzevar

BACKGROUND AND OBJECTIVES

Human T-cell lymphotropic virus type-I (HTLV-I) infection is considered as a public health challenge in endemic areas. The virus is associated with severe diseases, such as adult T-cell leukemia/lymphoma, and HTLV-I-associated myelopathy/tropical spastic paraparesis. One of the major routes of the HTLV-I transmission includes blood transfusion. Sabzevar is located in the endemic region of HTLV-I infection. The aim of the present study was to determine the seroprevalence of HTLV-I infection in the blood donors in Sabzevar.

MATERIALS AND METHODS

A total of 35,067 blood donors in Sabzevar from March 2009 to April 2012 who were screened with HTLV-I on the enzyme-linked immunosorbent assay screening test were included in this survey. Reactive samples that confirmed by western blot were considered to be seropositive cases. The required data were obtained from blood donors' database of blood transfusion service.

RESULTS

The overall prevalence of HTLV-1 based on the positive result of western blot test was 0.14%. The seropositive donors aged 17-59 years with a mean age of 38.10 ± 11.82. The prevalence rates of HTLV-I infection in 3 years of study were 0.19%, 0.14%, and 0.09%, respectively. A significant relation between age, sex, educational level, and history of blood donation was observed with seropositivity of HTLV-I.

CONCLUSION

The improvement of donor selection and laboratory screening caused a decline in the prevalence of infection in blood donors. Given the lower prevalence of infection in regular donors with lower age and higher educational level, more efforts should be done to attract blood donors from these populations.

Seroepidemiology of human T-cell lymphotropic virus type-1 (HTLV1) in Mashhad

INTRODUCTION

Human T-cell lymphotropic virus (HTLV-I) is associated with adult T cell leukemia/lymphoma (ATL) and HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP). The major routes of HTLV-I transmission are mother-to-child, sexual contact, and blood transfusion. Mashhad is one of the main endemic areas in the world for HTLV-I, and minimizing the risk of HTLV-I transmission through blood transfusion is one of the main duties of the Blood Transfusion Center in Mashhad. The aim of this study was to determine the prevalence of HTLV-I in the blood donor population in Mashhad during 2011-2013.

METHODS

All the blood donors in Mashhad from March 2011 to April 2013 who were diagnosed with HTLV-I on the ELISA screening test and the Western blot confirmatory test were included in this seroepidemiological study.

RESULTS

From 174,662 blood donors, 327 donors were confirmed to be infected with HTLV-I according to Western blot assay. The seropositive donors ranged in age from 17 to 59, and their mean age was 39.88±10.49 years. The overall prevalence rates of HTLV-I infection were calculated as 0.18% and 0.19%, respectively.

CONCLUSION

Due to the lower frequency of infection in regular blood donors, younger individuals, and people with higher education levels, the selection of blood donors from these populations should be further considered.

Epidemiological Aspects and World Distribution of HTLV-1 Infection

The human T-cell leukemia virus type 1 (HTLV-1), identified as the first human oncogenic retrovirus 30 years ago, is not an ubiquitous virus. HTLV-1 is present throughout the world, with clusters of high endemicity located often nearby areas where the virus is nearly absent. The main HTLV-1 highly endemic regions are the Southwestern part of Japan, sub-Saharan Africa and South America, the Caribbean area, and foci in Middle East and Australo-Melanesia. The origin of this puzzling geographical or rather ethnic repartition is probably linked to a founder effect in some groups with the persistence of a high viral transmission rate. Despite different socio-economic and cultural environments, the HTLV-1 prevalence increases gradually with age, especially among women in all highly endemic areas. The three modes of HTLV-1 transmission are mother to child, sexual transmission, and transmission with contaminated blood products. Twenty years ago, de Thé and Bomford estimated the total number of HTLV-1 carriers to be 10-20 millions people. At that time, large regions had not been investigated, few population-based studies were available and the assays used for HTLV-1 serology were not enough specific. Despite the fact that there is still a lot of data lacking in large areas of the world and that most of the HTLV-1 studies concern only blood donors, pregnant women, or different selected patients or high-risk groups, we shall try based on the most recent data, to revisit the world distribution and the estimates of the number of HTLV-1 infected persons. Our best estimates range from 5-10 millions HTLV-1 infected individuals. However, these results were based on only approximately 1.5 billion of individuals originating from known HTLV-1 endemic areas with reliable available epidemiological data. Correct estimates in other highly populated regions, such as China, India, the Maghreb, and East Africa, is currently not possible, thus, the current number of HTLV-1 carriers is very probably much higher.

Epidemiology of human T-cell lymphotropic virus type 1 infection in blood donors, Israel

The prevalence of infection with human T-cell lymphotropic virus type 1 (HTLV-1) in blood donors from Israel is 1 infection/100,000 persons. In donors originating from Eastern Europe, the Middle East, and Latin America, prevalences are 7.7, 14.6, and 20.4, respectively. HTLV-1 prevalence may be high outside areas where HTLV-1 previously was known to be endemic.

Mycosis fungoides in European Russia: No Antibodies to Human T Cell Leukemia Virus Type I Structural Proteins, but Virus-Like Sequences in Blood and Saliva

OBJECTIVE

Mycosis fungoides (MF) is the most frequent form of cutaneous T cell lymphoma (CTCL). Human T cell leukemia virus type 1 (HTLV-1) involvement in MF progression is a matter of debate. The goal of the investigation was to search for HTLV-1 markers in a group of MF patients from a nonendemic area to HTLV-1.

MATERIALS AND METHODS

Fifty MF patients and 60 healthy donors from Moscow and the Moscow region were examined for HTLV-1 markers by Western blot, PCR, nested PCR, PCR/Southern hybridization, TaqMan real-time PCR and sequencing.

RESULTS

Plasma samples from MF patients were repeatedly negative for antibodies to HTLV-1 structural proteins. HTLV-1 tax-related sequences (corresponding to the second exon) were found in blood from 20 of 50 MF patients and in 3 of 5 saliva specimens. Three of 8 sequenced tax-like amplimers were identical and 5 of 8 contained 1-2 substitutions. tax transcripts and antibodies to p40(tax) were detected in some 'PCR-tax'-positive MF patients. Defective HTLV-1 genomes were demonstrated in 2 of 50 MF patients. Phylogenetic analysis of the defective genome 5'-LTR sequence revealed a relationship with HTLV-1a sequences from the transcontinental subgroup of HTLV-1.

CONCLUSIONS

HTLV-1 tax-like sequences were revealed in blood and for the first time in saliva from MF patients living in an HTLV-1 nonendemic region. Expression of tax-like sequences was confirmed by both reverse transcription PCR and Western blot.

Is seroprevalence of HTLV-I/II among blood donors in Lebanon relevant?

Human T-cell lymphotropic virus type I (HTLV-I) is associated with certain hematologic and neurologic disorders. Seroprevalence studies demonstrated that the distribution of HTLV-I is heterogeneous worldwide and not specific to 1 region. Because blood is one of the major routes of transmission of the virus, blood banks of several countries routinely screen all blood donations for HTLV-I. The aim of the present study was to assess the seroprevalence rate of HTLV-I/II antibodies among Lebanese blood donors. Between August 2001 and March 2002, consecutive blood samples of 3529 blood donors were collected at blood banks of 4 major hospitals in Lebanon. Initial enzyme-linked immunosorbent assay (ELISA) screening resulted in 23 (0.7%) positive samples, of which 12 (0.3%) were reconfirmed positive by ELISA. Further analysis by Western blot resulted in 2 (0.06%) positive samples, of which 1 tested positive for HTLV-I by PCR (0.028%). Although its very low prevalence among Lebanese blood donors does not support routine screening of Lebanese blood donors for HTLV-I, screening of blood donors from other nationalities may be exercised, especially those from HTLV-I endemic areas.