HTLV-1/2 among high-risk groups in Argentina: molecular diagnosis and prevalence of different sexual transmitted infections

Human T Cell Lymphotropic Virus Type 1 Global Prevalence Associated with the Human Development Index: Systematic Review with Meta-Analysis

In 2012, the number of people infected with human T cell lymphotropic virus type 1 (HTLV-1) was estimated to be 10 million worldwide. Prevalence varies according to geographic location, ethnic factors, sex, age, populations exposed to risk factors, income, and education, reaching countries with the worst socioeconomic scenarios. There is a need to determine the current global prevalence of HTLV-1 and examine its association with countries' human development index (HDI) to provide data for global health policy. Systematic review with meta-analysis is according to PRISMA 2020 recommendations. It was registered at PROSPERO, CRD42021223146. Prevalence or cross-sectional studies of HTLV-1 infection with at least 100 participants, screening, and confirmatory serologic testing were included. Studies with incomplete or unavailable results or with duplicate information were excluded. Data were selected by two independent investigators and analyzed using R software, a metapackage that generated the forest plots [95% confidence interval (CI)]. Heterogeneity was assessed using the I² statistic, and funnel plot asymmetry was assessed using Egger's test. Countries were compared using an HDI cutoff ≥0.8. Methodological quality was assessed using Joanna Briggs Institute (JBI) criteria. The overall prevalence of HTLV-1 infection was 0.91% (95% CI: 0.80-1.02, p < .0001) and was higher in low HDI countries [1.18% (95% CI: 1.03-1.34)] than in high HDI countries [0.41% (95% CI: 0.27-0.57)]. Prevalence varied according to the populations studied: it was higher in the general population [1.65% (95% CI: 1.08-2.34)] compared to pregnant women [0.34% (95% CI: 0.17-0.57)] and blood donors [0.04% (95% CI: 0.01-0.08)]. Consistently, prevalence for each population group was higher in low HDI countries than in high HDI countries. The worldwide prevalence of HTLV-1 infection is highly heterogeneous, with a global prevalence of 0.91%. In high HDI countries, the observed prevalence is approximately three times lower than in low HDI countries. In the general population, the observed prevalence is about 5 times higher than in pregnant women and 41 times higher than in blood donors.

Making Visible HTLV Infection in a Non-endemic Area of Argentina

In Argentina, the human T-cell lymphotropic virus type 1 (HTLV-1) infection has been documented mainly among blood banks with a prevalence of ~0.02–0.046% for Buenos Aires city, 0.8% for the northeast, and 1% for the northwest; both areas are considered endemic for HTLV-2 and 1, respectively. Policies and specific guidelines for testing blood donors for HTLV are included since 2005. Screening for antibodies is performed at blood banks and confirmatory testing is performed at reference laboratories. There are no specific recommendations for the assistance of communities and individuals affected, nor referral to specialized clinics on the HTLV infection. In 2016, as a strategy of intervention, we opened a specialized clinical attendance in a referral infectious diseases public hospital for the comprehensive approach to patients with HTLV, offering follow-up and counseling for patients and their families for the early diagnosis of HTLV-1/2 and related diseases. During the study, 124 patients with presumptive HTLV positive diagnosis from blood bank, symptomatic patients (SPs), relatives, and descendants visited the unit. A total of 46 patients were HTLV positive (38 HTLV-1 and 8 HTLV-2). There were nine SPs (2 adult T-cell leukemia/lymphoma [ATL] and 7 HTLV-1-associated myelopathy/tropical spastic paraparesis [HAM/TSP]). All patients with HTLV-1 and−2 were offered to study their relatives. Two out of 37 (5.4%) descendants tested were positive for HTLV-1. Sexual partners were studied; among 6 out of 11 couples (54.5%) were found positive (5 HTLV-1 and 1 HTLV-2). Other relatives, such as mothers (1/2) and siblings (1/6), were positive for HTLV-1. According to the place of birth among HTLV-1 carriers, 58% were born in an endemic area or in countries where HTLV infection is considered endemic while for HTLV-2 carriers, 12.5% were born in an endemic area of Argentina. The proviral load (pVL) was measured in all, patients with HTLV-1 being higher in symptomatic compared with asymptomatic carriers. In addition, two pregnant women were early diagnosed during their puerperium and breastmilk replacement by formula was indicated. Inhibition of lactation was also indicated. Our study provides tools for a multidisciplinary approach to the infection and reinforces the importance of having specialized clinical units in neglected diseases, such as HTLV for counseling, clinical and laboratory follow-up, and providing useful information for patients for self-care and that of their families.

HTLV-1 Transmission and HIV Pre-exposure Prophylaxis: A Scoping Review

HIV pre-exposure prophylaxis (HIV-PrEP) is effective in reducing the likelihood of HIV acquisition in HIV-negative people at high risk of exposure. Guidelines recommend testing for sexually transmitted infections (STIs) before starting, and periodically on PrEP, including bacterial infections, HIV, hepatitis C virus, and, for those who are non-immune, hepatitis B virus. Diagnosed infections can be promptly treated to reduce onward transmission. HTLV-1 is not mentioned; however, it is predominantly sexually transmitted, causes adult T-cell leukaemia/lymphoma (ATL) or myelopathy in 10% of those infected, and is associated with an increased risk of death in those without any classically HTLV-associated condition. The 2021 WHO Technical Report on HTLV-1 called for the strengthening of global public health measures against its spread. In this scoping review, we, therefore, (1) discuss the epidemiological context of HIV-PrEP and HTLV-1 transmission; (2) present current knowledge of antiretrovirals in relation to HTLV-1 transmission prevention, including nucleos(t)ide reverse transcriptase inhibitors (NRTIs) and integrase strand transfer inhibitors (INSTIs); and (3) identify knowledge gaps where data are urgently required to inform global public health measures to protect HIV-PrEP users from HTLV-1 acquisition. We suggest that systematic seroprevalence studies among PrEP-using groups, including men who have sex with men (MSM), people who inject drugs (PWIDs), and female sex workers (FSWs), are needed. Further data are required to evaluate antiretroviral efficacy in preventing HTLV-1 transmission from in vitro studies, animal models, and clinical cohorts. PrEP delivery programmes should consider prioritizing the long-acting injectable INSTI, cabotegravir, in HTLV-1 endemic settings.

HTLV-1 and Co-infections

Human T lymphotropic virus type 1 (HTLV-1) is a retrovirus that causes lifelong T-cell infection in humans, impacting the host immune response. This virus causes a range of clinical manifestations, from inflammatory conditions, including neuronal damage (HTLV-1 associated myelopathy, HAM) to life-threatening leukemia (adult T-cell leukemia, ATL). Human T lymphotropic virus type 1 is also associated with increased risk of all-cause mortality, but the mechanisms remain unclear. As a blood-borne and sexually transmitted infection (STI), HTLV-1 shares transmission routes to many other pathogens and although it has worldwide distribution, it affects mainly those in low- and middle-income tropical areas, where the prevalence of other infectious agents is high. These factors contribute to a high incidence of co-infections in people living with HTLV-1 (PLHTLV). This comprehensive review addresses the impact of HTLV-1 on several co-infections and vice-versa. There is evidence of higher rates of HTLV-1 infection in association with other blood borne (HCV, HBV) and sexually transmitted (Syphilis, Chlamydia, HPV, HSV) infections but whether this represents increased susceptibility or opportunity is unclear. Higher frequency of Mycobacterium tuberculosis (MTb) and Mycobacterium leprae (M. leprae) is observed in PLHTLV. Reports of opportunistic infections and high frequency of crusted scabies in patients with HTLV-1 points to immune impairment in those individuals. Human T lymphotropic virus type 1 may influence the persistence of pathogens, exemplified by the higher rates of Schistosoma mansoni and Strongyloides stercoralis (St. stercoralis) treatment failure observed in PLHTLV. This retrovirus is also associated with increased tuberculosis (TB) severity with some evidence pointing to a deleterious impact on leprosy outcome as well. These findings are supported by immune alterations observed in those co-infected individuals. Although the role of HTLV-1 in HCV outcome is debatable, most data indicate that HTLV may negatively impact the clinical course of hepatitis C. Co-infections may also influence the risk of developing HTLV-1 associated disease, but data are still limited. The impact of HTLV-1 on the response to more common infections, might contribute to the increased mortality rate of HTLV-1. Large scale prospective controlled studies on the prevalence and impact of HTLV-1 in co-infections and vice-versa are needed. Human T lymphotropic virus type 1 impact in public health is broad. Measures to increase awareness and to prevent new infections are needed.

Work-Related Human T-lymphotropic Virus 1 and 2 (HTLV-1/2) Infection: A Systematic Review

Human T-lymphotropic virus 1 and 2 (HTLV-1/2) belong to the delta group of retroviruses which may cause a life-long infection in humans, HTLV-1 leading to adult T-cell leukemia/lymphoma and other diseases. Different transmission modes have been described, such as breastfeeding, and, as for other blood-borne pathogens, unsafe sexual activity, intravenous drug usage, and blood transfusion and transplantation. The present systematic review was conducted to identify all peer-reviewed studies concerning the work-related infection by HTLV-1/2. A literature search was conducted from January to May 2021, according to the PRISMA methodology, selecting 29 studies: seven related to health care workers (HCWs), five to non-HCWs, and 17 to sex workers (SWs). The findings showed no clear evidence as to the possibility of HTLV-1/2 occupational transmission in HCWs, according to the limited number and quality of the papers. Moreover, non-HCWs showed a higher prevalence in jobs consistent with a lower socioeconomic status or that could represent a familial cluster, and an increased risk of zoonotic transmission from STLV-1-infected non-human primates has been observed in African hunters. Finally, a general increase of HTLV-1 infection was observed in SWs, whereas only one paper described an increased prevalence for HTLV-2, supporting the urgent need for prevention and control measures, including screening, diagnosis, and treatment of HTLV-1/2, to be offered routinely as part of a comprehensive approach to decrease the impact of sexually transmitted diseases in SWs.

First molecular epidemiological study of hepatitis B and D in individuals infected with human T-lymphotropic virus 1/2 from Argentina

Human T-lymphotropic virus 1/2 (HTLV-1/2), hepatitis B virus (HBV), and hepatitis D virus (HDV) share transmission routes. Argentina shows low prevalence of HTLV-1/2, HBV, and HDV infections; however, this situation may vary according to the geographic region and group studied. The aim of this study was to estimate the prevalence of HBV and HDV infections and detect both viral genotypes in HTLV-1/2 individuals from Argentina. A total of 202 HTLV-1/2 confirmed samples (blood donors [BD] and individuals with risk factors for HTLV-1/2 [RF]) were tested for HBsAg and total anti-HBc by enzyme-linked immunosorbent assay. All reactive samples for some HBV markers were analyzed for HBV DNA characterization and HDV serological and molecular analysis. Total prevalence was 1.5% for HBsAg and 6.4% for anti-HBc. Prevalence was 23.1% for anti-HDV in all HBV-reactive samples. No significant difference was observed for HBV and HDV prevalence within HTLV subtypes. The population study showed that prevalence of anti-HBc was higher in the RF than in the BD population, with no significant differences between them. The HBsAg marker and anti-HDV were only found in RF, showing significant differences when compared to BD. Regarding molecular detection, one sample amplified for HBV DNA and none for HDV RNA. HBV sequence was classified as subgenotype F1b. New and updated background on serological markers of HBV and HDV infection in patients with HTLV-1/2 was provided.

Evaluation of the Inflammatory Cytokines and IL-10 Network in Individuals Co-infected With Human T-Cell Lymphotropic Virus and Hepatitis C Virus (HTLV/HCV)

Background

Co-infection between the human T-cell lymphotropic virus (HTLV) and the hepatitis C virus (HCV) can modify the natural history of HCV infection. The aim of this study was to describe the inflammatory cytokines and IL-10 network in patients co-infected with HTLV and HCV viruses in Bahia, Brazil.

Methods

Samples from 31 HTLV/HCV co-infected individuals and 27 HCV monoinfected individuals were evaluated. IFN-γ, TNF-α, IL-10, IL-8, and IL-1 cytokines were quantified by ELISA. Clinical, laboratory data were obtained from patient records. Serum levels of the cytokines were log₁₀-transformed and data mining was performed using Z-score statistics and correlation analysis.

Results

Co-infected individuals presented a tendency toward higher production of INF-γ compared to the HCV monoinfected group. Regarding cytokine pairs, there was a positive correlation (P-value < 0.05) between IL-1 and IL-8 in the HTLV/HCV co-infected group and uninfected controls, and two correlations in the HCV mono-infected group IL-8 – IL10 and IL- INF-γ – IL-10 pairs. There was no significant difference between the groups for the other parameters analyzed.

Conclusion

The results presented herein indicated that HTLV/HCV co-infection was associated with a trend in IFN-γ production while HCV-infected individuals presented a positive correlation with both inflammatory cytokines (IL-8 and IFN-γ) and the regulatory cytokine IL-10.

Prevalence and incidence of hepatitis C virus infection in men who have sex with men: a systematic review and meta-analysis

BACKGROUND

WHO has set targets for hepatitis C virus (HCV) elimination by 2030. We did a global systematic review of HCV prevalence and incidence in men who have sex with men (MSM) to provide updated estimates that can guide community education and public health policy.

METHODS

We did a systematic review and meta-analysis of studies published and listed on MEDLINE or Embase between Jan 1, 2000, and Oct 31, 2019, including conference proceedings. Studies were eligible if they reported measures of HCV prevalence or HCV incidence (or both) among MSM. Studies that relied on participants' self-reported HCV status with no laboratory confirmation were excluded. Pooled HCV estimates in MSM were stratified by HIV status and by injecting drug use, then by WHO region and by income level. Random-effects meta-analysis was done to account for between-study heterogeneity and examined using the I² statistic. Pooled HCV prevalence was also compared with HCV estimates in the general population and presented as prevalence ratios (PRs). In HIV-negative MSM, incidence estimates were stratified by use of HIV pre-exposure prophylaxis (PrEP). The systematic review was registered with PROSPERO, number CRD42020156262.

FINDINGS

Of 1221 publications identified, 194 were deemed to be eligible and included in the systematic review and meta-analysis. Overall, the pooled HCV prevalence in MSM was 3·4% (95% CI 2·8-4·0; I²=98·0%) and was highest in Africa (5·8%, 2·5-10·4) and South-East Asia (5·0%, 0·0-16·6). Globally, HCV prevalence was 1·5% (1·0-2·1) in HIV-negative MSM and 6·3% (5·3-7·5) in HIV-positive MSM. Compared with the general population, HCV prevalence was slightly higher in HIV-negative MSM (PR 1·58, 95% CI 1·14-2·01) and markedly higher (6·22, 5·14-7·29) in HIV-positive MSM. Pooled HCV prevalence was substantially higher in MSM who had ever injected drugs (30·2%, 22·0-39·0) or currently injected drugs (45·6%, 21·6-70·7) than in those who never injected drugs (2·7%, 2·0-3·6). In HIV-negative MSM, the pooled HCV incidence was 0·12 per 1000 person-years (95% CI 0·00-0·72) in individuals not on PrEP and 14·80 per 1000 person-years (9·65-20·95) in individuals on PrEP. HCV incidence in HIV-positive MSM was 8·46 per 1000 person-years (6·78-10·32).

INTERPRETATION

HIV-positive MSM are at substantially increased risk of HCV. Overall, HIV-negative MSM had a slightly higher prevalence of HCV than the general population but had a lower prevalence than HIV-positive MSM. High HCV incidence in more recent PrEP studies suggests that as PrEP use increases, greater HCV transmission might occur. HCV burden in MSM varies considerably by region, which is likely to be associated with variation in the prevalence of injecting drug use and HIV.

FUNDING

World Health Organization.

Lymphotropic Viruses EBV, KSHV and HTLV in Latin America: Epidemiology and Associated Malignancies. A Literature-Based Study by the RIAL-CYTED

The Epstein-Barr virus (EBV), Kaposi sarcoma herpesvirus (KSHV) and human T-lymphotropic virus (HTLV-1) are lymphomagenic viruses with region-specific induced morbidity. The RIAL-CYTED aims to increase the knowledge of lymphoma in Latin America (LA), and, as such, we systematically analyzed the literature to better understand our risk for virus-induced lymphoma. We observed that high endemicity regions for certain lymphomas, e.g., Mexico and Peru, have a high incidence of EBV-positive lymphomas of T/NK cell origin. Peru also carries the highest frequency of EBV-positive classical Hodgkin lymphoma (HL) and EBV-positive diffuse large B cell lymphoma, not otherwise specified (NOS), than any other LA country. Adult T cell lymphoma is endemic to the North of Brazil and Chile. While only few cases of KSHV-positive lymphomas were found, in spite of the close correlation of Kaposi sarcoma and the prevalence of pathogenic types of KSHV. Both EBV-associated HL and Burkitt lymphoma mainly affect young children, unlike in developed countries, in which adolescents and young adults are the most affected, correlating with an early EBV seroconversion for LA population despite of lack of infectious mononucleosis symptoms. High endemicity of KSHV and HTLV infection was observed among Amerindian populations, with differences between Amazonian and Andean populations.

Emerging sexually transmitted viral infections: Review of human T-lymphotropic virus-1 disease

Human T-lymphotropic virus-1 is a preventable sexually transmitted infection. In the majority of people it is asymptomatic, remaining undiagnosed and thereby contributing to its silent transmission. When it does manifest it causes significant morbidity and mortality. This review summarises the existing evidence for its role in sexual transmission and offers suggestions for those working in the area of sexual health. This is the third part of a series looking at novel sexually transmitted infections.

Human T-lymphotropic virus 1 and 2 among people who used illicit drugs in the state of Pará, northern Brazil

People who used illicit drugs (PWUDs) represent an important population group for acquisition and viral dispersion. In Brazil, high rates of the human T lymphotropic virus 1 (HTLV-1) and 2 (HTLV-2) have been reported in epidemiological studies. However, the epidemiological scenario of HTLV-1/2 infections in PWUDs is still poorly understood. Thus, this cross-sectional study determined the prevalence, frequency of subtypes and factors associated with HTLV-1/2 infections among PWUDs in the Brazilian state of Pará, an area considered endemic for this virus and with poor health services. Among 826 PWUDs, 53 (6.4%) presented anti-HTLV-1/2 antibodies by EIA and 44 (5.3%) presented proviral DNA by PCR. HTLV-1 and HTLV-2 were detected in 25 (3.0%) and 19 (2.3%) PWUDs, respectively. Subtypes 1a (25/44), transcontinental (23/44) and Japanese subgroups (2/44), 2b (6/44) and 2c (13/44) were identified. Involvement in illicit/criminal activity, daily use of illicit drugs, illicit drug use over 12 years, unprotected sex with other PWUDs, changes in genitalia (including ulcers and wounds), and more than 12 sexual partners were associated with HTLV-1/2 in PWUDs. This high prevalence and intense circulation of subtypes and subgroups of HTLV-1/2 is very worrying, and indicate the need for urgent actions for its control, prevention and treatment.

[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.

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.

Hepatitis C virus and human T-cell lymphotropic virus type 1 co-infection: impact on liver disease, virological markers, and neurological outcomes

OBJECTIVES

Human T-cell lymphotropic virus type 1 (HTLV-1) infection is associated with neurological abnormalities, such as HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and peripheral neuropathy (PN). Hepatitis C virus (HCV) infection is the leading cause of chronic liver disease worldwide, and causes PN in approximately 9% of patients. Because the interplay between these potentially neuropathogenic viruses in the same individual is still poorly understood, the clinical and laboratory outcomes of co-infected patients were evaluated and compared with those of controls.

METHODS

The prevalence rates of neurological and laboratory abnormalities were evaluated in HCV/HTLV-1 co-infected patients (n=50), and in subjects with single HCV (n=46) or HTLV-1 (n=150) infection.

RESULTS

A higher frequency of isolated PN was present in HCV-infected patients; this was not associated with cryoglobulinemia. No difference was found in the frequency of PN or HAM/TSP when co-infected subjects were compared to singly infected subjects. Hepatic involvement was present in HCV-infected subjects, as shown by increased levels of serum alanine aminotransferase, aspartate aminotransferase, gamma-glutamyl transferase, and bilirubin, in addition to thrombocytopenia. On the other hand, HCV/HTLV-1 co-infected individuals presented a better prognosis for hepatic involvement when compared with singly HCV-infected subjects.

CONCLUSIONS

These data suggest that HCV/HTLV-1 co-infection does not mutualistically alter the outcome with regard to neurological manifestations. Nonetheless, changes in the immunological environment induced by HTLV-1 infection could lead to a reduction in hepatic damage, even without significant HCV clearance.

Prevalence and phylogenetic analysis of HTLV-1 in a segregated population in Iran

Human T-lymphotropic virus type 1 (HTLV-1) infection is an important health issue that affects a variety of endemic areas. The Khorasan province, mainly its capital Mashhad in northeastern Iran, was reported to be as one of these endemic regions. Torbat-e Heydarieh, a large city Southwest border to Mashhad with a segregated population was investigated for the prevalence and associated risk factors of HTLV-1 infection in 400 randomly selected individuals. Blood samples were tested for the presence of HTLV-1 antibodies via the ELISA method and then were confirmed by an Immunoblot test. For the presence of HTLV-1 in lymphocytes of infected subjects, PCR was performed on LTR and TAX regions. DNA sequencing of LTR fragment was also carried out to determine the phylogenetic of HTLV-1, using the Maximum likelihood method. HTLV-1 sero-reactivity (sero-prevalence) among the study population was 2% (8/400), of which 1.25% had HTLV-1 provirus in lymphocytes (actual prevalence). HTLV-1 infection was significantly associated with the age, marital status, and history of blood transfusion (P < 0.05). However, there were no statistical differences between HTLV-1 infection, and gender, surgery, and hospitalization. In regression analysis, age showed the most significant correlation with the infection (P = 0.006, OR = 4.33). Based on our phylogenetic study, the HTLV-1 prevalent sequence type of Torbat-e Heydarieh belongs to the cosmopolitan subtype A. HTLV-1 prevalence in Torbat-e Heydarieh (1.25%) is low comparing to those of both Mashhad (2-3%) and Neishabour (3.5-5%) in the province of Khorasan. Thus, traveling mobility and population mixing such as marriage, bureaucratic affairs, occupation, and economic activities could be the usual routs of HTLV-1 new wave of spreading in this segregated city.

Low Proviral Load is Associated with Indeterminate Western Blot Patterns in Human T-Cell Lymphotropic Virus Type 1 Infected Individuals: Could Punctual Mutations be Related?

BACKGROUND

indeterminate Western blot (WB) patterns are a major concern for diagnosis of human T-cell lymphotropic virus type 1 (HTLV-1) infection, even in non-endemic areas.

OBJECTIVES

(a) to define the prevalence of indeterminate WB among different populations from Argentina; (b) to evaluate if low proviral load (PVL) is associated with indeterminate WB profiles; and (c) to describe mutations in LTR and tax sequence of these cases.

RESULTS

Among 2031 samples, 294 were reactive by screening. Of them, 48 (16.3%) were WB indeterminate and of those 15 (31.3%) were PCR+. Quantitative real-time PCR (qPCR) was performed to 52 HTLV-1+ samples, classified as Group 1 (G1): 25 WB+ samples from individuals with pathologies; Group 2 (G2): 18 WB+ samples from asymptomatic carriers (AC); and Group 3 (G3): 9 seroindeterminate samples from AC. Median PVL was 4.78, 2.38, and 0.15 HTLV-1 copies/100 PBMCs, respectively; a significant difference (p=0.003) was observed. Age and sex were associated with PVL in G1 and G2, respectively. Mutations in the distal and central regions of Tax Responsive Elements (TRE) 1 and 2 of G3 were observed, though not associated with PVL.The 8403A>G mutation of the distal region, previously related to high PVL, was absent in G3 but present in 50% of WB+ samples (p = 0.03).

CONCLUSIONS

indeterminate WB results confirmed later as HTLV-1 positive may be associated with low PVL levels. Mutations in LTR and tax are described; their functional relevance remains to be determined.

Sexual transmission of human T-cell lymphotropic virus type 1

Human T-cell lymphotropic virus type 1 (HTLV-1) is endemic in many parts of the world and is primarily transmitted through sexual intercourse or from mother to child. Sexual transmission occurs more efficiently from men to women than women to men and might be enhanced by sexually transmitted diseases that cause ulcers and result in mucosal ruptures, such as syphilis, herpes simplex type 2 (HSV-2), and chancroid. Other sexually transmitted diseases might result in the recruitment of inflammatory cells and could increase the risk of HTLV-1 acquisition and transmission. Additionally, factors that are associated with higher transmission risks include the presence of antibodies against the viral oncoprotein Tax (anti-Tax), a higher proviral load in peripheral blood lymphocytes, and increased cervicovaginal or seminal secretions. Seminal fluid has been reported to increase HTLV replication and transmission, whereas male circumcision and neutralizing antibodies might have a protective effect. Recently, free virions were discovered in plasma, which reveals a possible new mode of HTLV replication. It is unclear how this discovery might affect the routes of HTLV transmission, particularly sexual transmission, because HTLV transmission rates are significantly higher from men to women than women to men.

Characterization of overt and occult hepatitis B virus infection among HTLV-1 positive healthy carriers in the Northeast of Iran; AN HTLV-I endemic area

To date, no studies have provided data on hepatitis B virus (HBV) prevalence among asymptomatic, healthy human T-lymphotropic virus (HTLV-I) positive carriers. This sero- and molecular epidemiology study was performed on patients in the Northeast of Iran, which is an endemic area for HTLV-I infection. A total of 109 sera were collected from HTLV-I positive healthy carriers who were admitted to Ghaem Hospital, Mashhad City. All were tested for HBV serology and subsequently, real time PCR was carried out on the samples, regardless of the results of the serology. Standard PCR and direct sequencing were applied on positive samples. All cases were negative for HBsAg, Anti-HBc, and anti-HBs were positive in 34 (31.1%), and 35 (32%) individuals, respectively. There were 19 (17.4%) cases that were positive only for anti-HBs, and they had already received HBV vaccine. 16 (15%) were positive for both anti-HBs and anti-HBc, indicating a past-resolved HBV infection. 18 (16.5%) were isolated as anti-HBc, and 56 (51.3%) were negative for all HBV serological markers. Only one subject (0.9%) had detectable HBV DNA (2153 copy/ml), and assigned as being an occult HBV infection. The low prevalence of HBsAg, despite the high percentage of anti-HBc positive cases, might be related to the suppression effect of HTLV-I on surface protein expression. The low prevalence of HBV infection among HTLV-I positive healthy carriers from an endemic region, indicates that the epidemiology of HTLV-I and HBV coinfection is related to the endemicity of HBV in that region, rather than HTLV-I endemicity.

Epidemiological analysis of HTLV-1 and HTLV-2 infection among different population in Central China

Background

HTLV-1 and HTLV-2 are retroviruses linked etiologically to various human diseases, and both of them can be transmitted by vertical route, sexual intercourse, blood transfusion and intravenous drug use. Recently, some HTLV-infected cases have been reported and this virus is mainly present in the Southeast coastal areas in China, but has not been studied for the people in Central China.

Objectives

To know the epidemiologic patterns among different population samples in Central China and further identify risk factor for HTLV-1 and HTLV-2 infection.

Methods

From January 2008 to December 2011, 5480 blood samples were screened for HTLV-1/2 antibodies by using enzyme immunoassay, followed by Western Blot.

Results

The prevalence of HTLV-1 and HTLV-2 was found with infection rates 0.13% and 0.05% among all population samples for HTLV-1 and HTLV-2, respectively. The highest percentages of infection, 0.39% and 0.20%, were found in the high risk group, while only 0.06% and 0.03% in the blood donor group. There was only one case of HTLV-1 infection (0.11%) among patients with malignant hematological diseases. Of seven HTLV-1 positive cases, six were co-infected with HBV, two with HCV and one with HIV. Among three HTLV-2 positive individuals all were co-infected with HBV, one with HCV.

Conclusions

HTLV-1 and HTLV-2 have been detected in the Central China at low prevalence, with the higher infection rate among high risk group. It was also found that co-infection of HTLV-1/2 with HIV and HBV occurred, presumably due to their similar transmission routes. HTLV-1/2 antibody screen among certain population would be important to prevent the spread of the viruses.

Predominance of human lymphotropic T cell virus type 2 subtype B in urban populations of Argentina

Human T-lymphotropic virus subtype b (HTLV-2b) infection has been described among aborigines from Northern Argentina, while HTLV-2a has been described in an injecting drug user (IDU) from a Central region, similar to the situation in Spain, the United States, and Brazil. In this study, 22 of the 26 strains analyzed from blood donors and HIV-1(+) individuals were HTLV-2b (84.6%) clustering with Amerindian references, while 4 HIV-1(+) (15.4%) were HTLV-2a. HTLV-2a sequences were closely related to Brazilian references in contrast to the previous Argentinean IDU strain that clustered with Africans and Amerindians from North America. In summary, these findings show that HTLV-2b is the major strain circulating in an urban population of Argentina. HTLV-2a/b could have been introduced from endemic South American countries such as Brazil and because of contact with other populations such as IDUs from Europe despite its introduction due to the increasing internal migration of aborigines to large urban centers. Considering this results and recent data about the dissemination of HTLV-1 in residents of Buenos Aires city, new studies among non-at-risk groups for HTLV-1/2 infection should be performed.

Divergent strains of human T-lymphotropic virus type 1 (HTLV-1) within the Cosmopolitan subtype in Argentina

HTLV-1 Cosmopolitan subtype Transcontinental subgroup A has been described among aboriginal communities from the northwest endemic area of Argentina. Moreover, Transcontinental subgroup A and the Japanese subgroup B were reported among blood donors from the nonendemic central region of the country. We carried out the first HTLV-1 phylogenetic study in individuals residing in Buenos Aires capital city. Phylogenetic analysis performed on the LTR region showed that all 44 new strains clustered within the Cosmopolitan subtype, with 42 (95.4%) belonging to Transcontinental subgroup A. Of them, 20 (45.5%) strains grouped in the large Latin American cluster and 4 (9.1%) in the small Latin American cluster. The majority of them belonged to individuals of nonblack origin, grouped with Amerindian strains. Three (6.8%) were closely related to South African references and two monophyletic clusters including only HIV/HTLV-1 coinfected individuals were observed. Interestingly, two (4.5%) new sequences (divergent strains) branched off from all five known Cosmopolitan subgroups in a well-supported clade. In summary, these findings show that HTLV-1 Cosmopolitan subtype Transcontinental subgroup A is infecting residents of Buenos Aires, a nonendemic area of Argentina, and confirm the introduction of divergent strains in the country.