Prevalence and molecular characterization of human T cell leukemia virus type 2 in a group of intravenous drug users coinfected with HIV type 1 in Portugal

Distribution of Human Immunodeficiency Virus and Human T-Leukemia Virus Co-infection in Bahia, Brazil

Human Immunodeficiency Virus (HIV) and Human T-Leukemia Virus (HTLV) are retroviruses that share similar routes of transmission. In Brazil, the prevalence of HIV and HTLV varies according to geographic region. The state of Bahia, located in the Northeast region, is considered endemic for both retroviruses. The present study aimed to characterize the frequency of HIV/HTLV coinfection and evaluate the geographic distribution of coinfection throughout the state. This cross-sectional study was conducted at the state's Central Laboratory of Public Health (LACEN-BA) and included all samples from 2004 to 2013 submitted to serological testing for anti-HIV and anti-HTLV-1/2, screened by chemiluminescence/ELISA and confirmed by Western blot. Infection rates are expressed as the number of infected individuals per 100,000 inhabitants from each municipality. A total of 129,158 samples originating from 358/417 (85.8%) municipalities in Bahia were evaluated. HTLV was detected in 2.4% of the HIV-positive samples (n = 42) compared to 0.5% of those with negative HIV serology (n = 677) (OR: 4.65; CI: 3.39–6.37). HIV/HTLV coinfection was more frequent in women (69.0%); the median age of coinfected individuals was 47.2 years [interquartile range (IQR): 41.6–55.4 years]. In the 14/417 (3.4%) municipalities where at least one case of HIV/HTLV coinfection was detected, the overall HTLV coinfection rate in HIV-positive samples was 0.25 (range: 0.17–13.84) per 100,000 inhabitants. Most cases of HIV/HTLV-1 coinfection (21/37, 57%) were concentrated in the municipality of Salvador. Isolated instances (one or two cases) of HIV/HTLV-1 coinfection were distributed across municipalities known to be endemic for HTLV infection.

No significant HTLV seroprevalence in German people who inject drugs

Background

Although human T-lymphotropic virus (HTLV) is transmitted via the same routes as human immunodeficiency virus (HIV), its worldwide seroprevalence differs drastically because HTLV is transmitted mainly via infected cells rather than free virus. The sharing of needles and other equipment places people who inject drugs (PWID) at particularly high-risk for such blood-borne diseases.

Methods

To validate the methodology used to process and analyze the dried blood spots (DBS) utilized in the study, dried serum spots (DSS) with dilutions of sera from known HTLV infected individuals were analyzed by ELISA and Western blot. DBS collected between 2011 and 2015 from 2,077 PWID in eight German cities recruited by respondent-driven sampling were tested for HTLV-specific antibodies.

Results

The validation demonstrated that the use of DSS allowed identification of samples with even low titers of HTLV-specific antibodies, although a confirmatory Western blot with an additional venous blood sample would often be required. Despite numerous HIV and HCV positive individuals being identified within the study population, none tested positive for HTLV.

Conclusion

While the HIV and HCV prevalences in German PWID are comparable to those in other European countries, the very low prevalence of HTLV reflects the situation in the general population.

A multicentre sero-behavioural survey for hepatitis B and C, HIV and HTLV among people who inject drugs in Germany using respondent driven sampling

Background

People who inject drugs are at high risk for hepatitis B, hepatitis C and HIV. HTLV was reported by neighboring countries to be prevalent in this population, but the situation for Germany is unclear. To generate seroprevalence and related behavioural data and to enhance prevention efforts against these infections for drug users in Germany, a multicentre sero- and behavioural survey was initiated. People who inject drugs are not well reached by services for testing and counselling for blood-borne infections in Germany. An interventional part of the study is intended to prove feasibility and acceptance of testing and counselling in low-threshold drop-in settings.

Methods/Design

Between May 2011 and March 2015, eligible participants (persons having injected drugs within the last 12 months, aged 16 years+, and living in the study city) are recruited by respondent driven sampling, using low-threshold drop-in facilities as study-sites in eight German cities with large drug scenes. Calculated sample size is 2,033 participants. Capillary blood samples collected as dried blood spots are anonymously tested for serological and molecular markers of hepatitis B and C, HIV, and HTLV I and II. A detailed face-to-face-interview about hepatitis- and HIV-related knowledge, former testing, imprisonment, sexual and injecting risk behaviour is conducted with participants. Staff is trained to offer pre- and post-test-counselling of blood-borne infections and HIV rapid testing to participants.

Discussion

We chose respondent driven sampling for recruitment of participants to improve representativeness of results. Persons, who are not reached by the facility where the study is conducted, are aimed to be included by recruitment through their personal social network of injecting drug users. To reduce differential biases in the questions on knowledge of transmission and prevention of infections, we present true statements on hepatitis B, C and HIV, their possible routes of transmission and measures of prevention to participants. Participants are told that the statements are true and are asked to answer if they knew this fact already or if it is new to them. In case of knowledge gaps they are offered free targeted counselling as well as free HIV rapid testing and post-test counselling of HIV and hepatitis test results.

Molecular characterization of human T cell leukemia virus type 1 subtypes in a group of infected individuals diagnosed in Portugal and Spain

Over the past decade, Portugal and Spain received large numbers of immigrants from HTLV-1 endemic areas. Our aim was to investigate the diversity of subtypes circulating in these two countries and the introduction of new variants. We performed a molecular analysis of HTLV-1 strains in patients diagnosed since 1998. LTR and env proviral sequences from 26 individuals were analyzed to generate phylogenetic trees along with reference HTLV-1 subtypes from several geographic origins. Epidemiological and clinical data were recorded. Most subjects were immigrants (57.7%) from South America and Africa. All isolates belonged to the cosmopolitan A subtype. Most carried the transcontinental subgroup A, but five subjects carried subgroup D and one carried subgroup C, previously unreported in Europe. HTLV strains showed separate clusters linked to the patients' geographic origin. Although subjects with HTLV-1 infection tend not to be engaged in high-risk practices, silent dissemination of a broad diversity of HTLV-1 viruses may still occur.