Human T cell lymphotropic viruses (HTLV-I/II) in South America: Should it be a public health concern?

Association Between Trace Element Status and Depression in HTLV-1-Infected Patients: a Retrospective Cohort Study

Depression and Anxiety are two important public health problems that are known to be associated with viral infections. The association between the intake of nutrients such as zinc and copper with symptoms of depression has been studied previously. The aim of the current study was to investigate the association between depression with human T cell lymphotropic virus type 1 (HTLV-1) infection and serum content of zinc and copper in a large Iranian population cohort. The study population consisted of 279 HTLV-1-positive patients who were identified after recruitment as part of a large cohort study: the Mashhad Stroke and Heart Association Disorder (MASHAD) study. They were divided into two groups of diagnosed with or without depression based on their symptoms. Serum zinc and copper levels of all subjects were measured using the flame atomic absorption spectrometry. The population sample comprised of 279 individuals infected with HTLV-1 of whom 192 (68.8%) were women. The mean serum zinc in the group with and without depression was 78.69 ± 13.79 μg/dl and 86.87 ± 19.44 μg/dl, respectively (p < 0.001). Also, the serum copper level was higher in the depressive group (116.75 ± 39.56) than in the non-depressive group (104.76 ± 30.77) (p 0.004). The association between serum zinc and copper with depression in HTLV-1-infected patients which was shown in this study could be considered in the treatment strategies in these patients.

Sentidos da interrupção da amamentação devido infeção pelo vírus linfotrópico de células T humanas do tipo 1( HTLV-1)

Resumo Objetivo Compreender os sentidos da inibição da amamentação como prevenção da transmissão vertical entre mulheres vivendo com HTLV-1 (MVHTLV). Métodos Trata-se de pesquisa qualitativa com observação participante e entrevistas em profundidade, por meio de roteiro temático, pela análise de conteúdo temática de Bardin, pré-testado e realizados com 13 pessoas - 11 mulheres e dois homens - maiores de 18 anos, diagnosticados com HTLV-1 e sem co-infecções, entre Junho/2006 a Abril/2008, em sala reservada de centro especializado em São Paulo, onde atuava a pesquisadora, psicóloga, com familiaridade e acesso aos usuários. A seleção dos sujeitos ocorreu por conveniência durante a observação participante. Os relatos dos sujeitos foram gravados, transcritos e analisados na busca dos sentidos e significados para elaboração das categorias e, foram apresentados trechos destes, identificados por nomes fictícios. Resultados A inibição da amamentação é uma decisão complexa dificultada em um contexto de desconhecimento dessa infecção pela equipe de saúde. Conclusão O desconhecimento do HTLV-1 no contexto hospitalar se torna um risco para a transmissão vertical desse vírus, além de consequências emocionais significativas. Indica-se a necessidade de informação e formação da equipe de saúde para um cuidado integral e o acolhimento das necessidades específicas de MVHTLV.

Prevalence of human T-lymphotropic virus type 1 infection among blood donors in mainland China: a meta-analysis

BACKGROUND

Human T-lymphotropic virus type 1 (HTLV-1) is considered to be the etiological agent of adult T-cell leukemia/lymphoma (ATL) and HTLV-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Blood transfusion is a common transmission pathway for HTLV-1. However, no surveys to determine the overall prevalence of HTLV-1 infection and HTLV-1 genotypes among blood donors on the Chinese mainland have yet been conducted.

METHODS

A systematic review and meta-analysis of the peer-reviewed literature on this topic was carried out. Data manipulation and statistical analyses were performed using the Comprehensive Meta Analysis Version 2.0 program.

RESULTS

Forty-four eligible articles involving 458525 blood donors were selected. Analysis revealed the pooled prevalences of HTLV-1 infection among blood donors in Fujian and Guangdong provinces to be 9.9/10000 (95% confidence interval (CI) 4.4/10000-22.2/10000) and 2.9/10000 (95% CI 1.7/10000-4.8/10000), respectively; there were only two cases of HTLV-1 infection among 204763 donors in other areas of the Chinese mainland. In addition, 40 of 42 (95.2%) HTLV-1 isolates belonged to the Transcontinental subgroup A of the HTLV-1 subtype A (Cosmopolitan subtype).

CONCLUSIONS

The prevalence of HTLV-1 infection among blood donors is low and restricted mainly to the provinces of Fujian and Guangdong. Most isolates belong to the Transcontinental subgroup within HTLV-1 subtype A.

HTLV-1 and -2 infections among 10 indigenous groups in the Peruvian Amazon

Infections with HTLV-1 and -2 were detected in 12 (1.9%) and 6 (0.9%) indigenous individuals living in 27 Amazonian villages in Peru. All infections occurred in Shipibo-Konibo people. HTLV was more common among participants living in villages distant from larger port cities and women with non-monogamous sexual partners.

Descriptive study of HTLV infection in a population of pregnant women from the state of Pará, Northern Brazil

INTRODUCTION

In Brazil, studies have shown that HTLV seroprevalence among pregnant women varies from 0 to 1.8%. However, this seroprevalence was unknown in the State of Pará, Brazil. The present study describes, for the first time, the HTLV seroprevalence among pregnant women from the State of Pará, Northern Brazil.

METHODS

13,382 pregnant women were submitted to HTLV screening during prenatal care, and those with non-seronegative results to anti-HTLV were submitted to Western blot (WB) test to confirm and separate HTLV-1 and HTLV-2 carriers.

RESULTS

HTLV seroprevalence in the population of pregnant women was 0.3%, and HTLV-1 was identified in 95.3% of patients. The demographic profile of HTLV carriers was as follows: women with age between 20 and 40 years old (78.4%); residing in the metropolitan region of Belém, Pará (67.6%); and with educational level of high school (56.8%). Other variables related to infection were as follows: beginning of sexual intercourse between the age of 12 and 18 years old (64.9%) and have being breastfed for more than 6 months (51.4%). Most of the women studied had at least two previous pregnancies (35.1%) and no abortion (70.3%). Coinfections (syphilis and HIV) were found in 10.8% (4/37) of these pregnant women.

CONCLUSIONS

Seroprevalence of HTLV infection in pregnant women assisted in basic health units from the State of Pará, Northern Brazil, was 0.3% similar to those described in other Brazilian studies. The variables related to infection were important indicators in identifying pregnant women with a higher tendency to HTLV seropositivity, being a strategy for disease control and prevention, avoiding vertical transmission.

Living invisible: HTLV-1-infected persons and the lack of care in public health

INTRODUCTION

Human T-cell lymphotropic virus type 1 (HTLV-1) infection is intractable and endemic in many countries. Although a few individuals have severe symptoms, most patients remain asymptomatic throughout their lives and their infections may be unknown to many health professionals. HTLV-1 can be considered a neglected public health problem and there are not many studies specifically on patients' needs and emotional experiences.

OBJECTIVE

To better understand how women and men living with HTLV-1 experience the disease and what issues exist in their healthcare processes.

METHODS

A qualitative study using participant observation and life story interview methods was conducted with 13 symptomatic and asymptomatic patients, at the outpatient clinic of the Emilio Ribas Infectious Diseases Institute, in Sao Paulo, Brazil.

RESULTS AND DISCUSSION

The interviewees stated that HTLV-1 is a largely unknown infection to society and health professionals. Counseling is rare, but when it occurs, focuses on the low probability of developing HTLV-1 related diseases without adequately addressing the risk of infection transmission or reproductive decisions. The diagnosis of HTLV-1 can remain a stigmatized secret as patients deny their situations. As a consequence, the disease remains invisible and there are potentially negative implications for patient self-care and the identification of infected relatives. This perception seems to be shared by some health professionals who do not appear to understand the importance of preventing new infections.

CONCLUSIONS

Patients and medical staff referred that the main focus was the illness risk, but not the identification of infected relatives to prevent new infections. This biomedical model of care makes prevention difficult, contributes to the lack of care in public health for HTLV-1, and further perpetuates the infection among populations. Thus, HTLV-1 patients experience an "invisibility" of their complex demands and feel that their rights as citizens are ignored.

Phylogenetic and similarity analysis of HTLV-1 isolates from HIV-coinfected patients from the south and southeast regions of Brazil

HTLV-1 is endemic in Brazil and HIV/HTLV-1 coinfection has been detected, mostly in the northeast region. Cosmopolitan HTLV-1a is the main subtype that circulates in Brazil. This study characterized 17 HTLV-1 isolates from HIV coinfected patients of southern (n=7) and southeastern (n=10) Brazil. HTLV-1 provirus DNA was amplified by nested PCR (env and LTR) and sequenced. Env sequences (705 bp) from 15 isolates and LTR sequences (731 bp) from 17 isolates showed 99.5% and 98.8% similarity among sequences, respectively. Comparing these sequences with ATK (HTLV-1a) and Mel5 (HTLV-1c) prototypes, similarities of 99% and 97.4%, respectively, for env and LTR with ATK, and 91.6% and 90.3% with Mel5, were detected. Phylogenetic analysis showed that all sequences belonged to the transcontinental subgroup A of the Cosmopolitan subtype, clustering in two Latin American clusters.

HTLV-1 associated myelopathy diagnosed during lepromatous leprosy reaction treatment: a case report

Leprosy and human T cell lymphotropic virus type 1 infection are prevalent in Brazil. Coinfection by Mycobacterium leprae and HTLV-1 is reviewed and a case is reported. A 59 year-old woman was followed and HTLV-1 associated myelopathy was diagnosed during leprosy treatment. The clinical and neurological aspects of this unusual association were initially reviewed. Immunological markers and the possible prognoses due to the association of the diseases were discussed. The unexpected association of leprosy and HTLV-1 associated myelopathy may occur in endemic areas and causes difficulties in determining the correct diagnosis and adequate management of the neurological manifestations.

Stable human T-cell lymphotropic virus type 1 (HTLV-1) subtype a/subgroup a endemicity in Amerindians from Northwest Argentina: a health problem to be resolved

Jujuy province, in Northwest Argentina, is known to be endemic for HTLV-1 infection. Moreover, foci of HTLV-1 associated pathologies have also been described in this region. To gain an insight into the current situation of HTLV-1/2 in this endemic area, a seroprevalence and phylogenetic study was performed among a Kolla community from Abra Pampa city and surroundings. Out of 112 individuals, 11 (9.8%) were confirmed as HTLV-1 positive and no HTLV-2 infection was detected. The phylogenetic analysis of the LTR region showed that all the HTLV-1 sequences belonged to the Cosmopolitan subtype a/transcontinental subgroup A, and were closely related to reference sequences from Peru, Argentina, and the South of Brazil (P = 0.82). Considering the cultural and historical features of this community and in spite of the mandatory detection of anti-HTLV-1/2 antibodies in blood banks since 2005, it would be important to implement new public health measures focused on decreasing HTLV-1 transmission in this endemic area.

Anti-Tax antibody levels in asymptomatic carriers, oligosymptomatic carriers, patients with rheumatologic disease or with HAM/TSP do not correlate with HTLV-1 proviral load

BACKGROUND

HTLV-1 infects millions of people around the world and induces myelopathy (HAM/TSP), adult T-cell leukemia (ATL) or other inflammatory or rheumatologic diseases. The host-virus interaction causes asymptomatic carriers to develop HAM/TSP. Biomarkers are needed to predict patients who are at risk for HAM/TSP. Tax is highly immunogenic and is a major target protein recognized by cytotoxic T lymphocytes. Anti-Tax antibodies are involved in HAM/TSP pathogenesis.

OBJECTIVES

To assess anti-Tax IgG reactivity with a flow cytometry assay (FCA) using an infection/transfection system with Vaccinia virus and pLW44/Tax-expressing Tax and to correlate the anti-Tax response and the HTLV-1 proviral load.

STUDY DESIGN

: We enrolled 81 individuals: 9 HTLV-1 seronegative (NP) and 72 HTLV-1 positive (23 HTLV-1 asymptomatic carriers (AC), 12 oligosymptomatic patients (OL), 7 with rheumatologic diseases (DR) and 30 with HAM/TSP (HT)). Anti-Tax reactivity was assessed by FCA, and HTLV-1 proviral load was measured with real time PCR.

RESULTS

The HT and DR groups showed greater anti-Tax IgG reactivity (p<0.001 and p<0.05 comparing HT to the OL and AC group, respectively; p<0.05 comparing DR to the OL group), and the reactivity in the DR+HT group was significantly different when compared to the AC group (p<0.05) and to the OL group (p<0.001). The proviral load was higher in the HT group compared to the OL (p<0.001) and in the HT+DR group compared to OL (p<0.001). There was no correlation between anti-Tax IgG reactivity and proviral load in any of the HTLV-1-infected groups.

CONCLUSION

These findings suggest that although anti-Tax IgG reactivity and the HTLV-1 proviral load are important markers of the development of HTLV-1-associated diseases, their levels are not correlated.

Epidemiology, treatment, and prevention of human T-cell leukemia virus type 1-associated diseases

Human T-cell leukemia virus type 1 (HTLV-1), the first human retrovirus to be discovered, is present in diverse regions of the world, where its infection is usually neglected in health care settings and by public health authorities. Since it is usually asymptomatic in the beginning of the infection and disease typically manifests later in life, silent transmission occurs, which is associated with sexual relations, breastfeeding, and blood transfusions. There are no prospects of vaccines, and screening of blood banks and in prenatal care settings is not universal. Therefore, its transmission is active in many areas such as parts of Africa, South and Central America, the Caribbean region, Asia, and Melanesia. It causes serious diseases in humans, including adult T-cell leukemia/lymphoma (ATL) and an incapacitating neurological disease (HTLV-associated myelopathy/tropical spastic paraparesis [HAM/TSP]) besides other afflictions such as uveitis, rheumatic syndromes, and predisposition to helminthic and bacterial infections, among others. These diseases are not curable as yet, and current treatments as well as new perspectives are discussed in the present review.

[Prevalence of infection due to HTLV-1 in remnant quilombos in Central Brazil]

This study aimed to determine the prevalence of HTLV-1 infection among remnant black quilombo communities in Central Brazil. A total of 1,837 individuals were evaluated, among whom nine were HTLV-1/2 seropositive according to ELISA. All of them were positive for HTLV-1 by means of Western blot and/or PCR, thus resulting in a prevalence of 0.5% (95% CI: 0.2-1.0). The HTLV-1 infected individuals ranged in age from 11 to 82 years. The majority of them were females. Regarding risk characteristics, histories of breastfeeding, blood transfusion, multiple sexual partners and sexually transmitted diseases were reported by these individuals. The findings from this study indicate the importance of identifying HTLV-1 infected individuals, as a strategy for infection control and prevention in these remnant quilombos.

Lookback study of HTLV-1 and 2 seropositive donors and their recipients in Belo Horizonte, Brazil

The objective of this study was to perform lookback study in recipients of blood components from human T-lymphotropic virus (HTLV) seropositive donors. HTLV-1/2 may be transmitted by blood transfusion. Brazil is an endemic area for the virus and its screening in blood donors is mandatory since 1993. Hemominas Foundation (HF) is the public transfusion centre in Minas Gerais, Brazil. Data on HTLV-1/2 seropositive donors and recipients from 1993 to 2004 were obtained at HF and 24 contracting hospitals. From 1993 to 2004, HTLV-1/2 enzyme immunoassay (EIA) was performed in 918 678 donations of approximately 422 600 blood donor candidates. Of these, 456 donors (0.1%) were reactive and confirmed by Western blot (WB): 449 HTLV-1 and 7 HTLV-2. Sixty-six (14.5%) were repeat donors and had 194 blood cellular components produced from their previous donations. Of the distributed components, 119/146 (81.5%) had the recipient traced, with a total of 114 individuals. Of these, only 13 recipients were tested: six (46%) were HTLV-1 positive (four recipients of red cell units, two of platelets) and seven (54%) were negative (six of red cell units and one of platelets). Eleven did not respond and 62/114 (54.0%) were deceased. Another 28/114 (25.0%) could not be located. All six seropositive HTLV-1 recipients identified had no symptoms suggestive of HTLV-1-associated diseases. Acellular components, when used alone, were not associated with HTLV seropositivity. HTLV-1 transmission by cellular blood components occurred before screening for the virus was introduced. Haemovigilance was difficult to perform due to unavailability of computer systems before 1999 and to inadequate medical records at hospitals.

Myelopathy and adult T-cell leukemia associated with HTLV-1 in a young patient with hearing loss as the initial manifestation of disease

A young male developed hearing loss, vertigo, headache and facial palsy. Neurological examination did not show any abnormalities. Two years later, cervical lymphadenopathy, hepatosplenomegaly and atypical lymphocytes in peripheral blood revealed leukemia. At the same time, acquired ichthyosis was observed. Subsequently, neurological abnormalities revealed myelopathy associated with HTLV-1, due to vertical transmission.

Adult T-cell leukemia/lymphoma (ATL) presenting in the skin: clinical, histological and immunohistochemical features of 52 cases

BACKGROUND

Adult T-cell leukemia/lymphoma (ATL) is a severe disease caused by HTLV-I. This paper describes the clinicopathological and immunohistochemical findings of 52 cases of ATL with skin involvement and investigates whether there is any relationship between median survival time (MST) and histological patterns, primary cutaneous involvement and CD8 positivity.

MATERIAL AND METHODS

All cases were HTLV-I+ and HIV- and were clinically classified. HTLV-I proviral integration was investigated in atypical cases. Immunohistochemistry was performed using CD3, CD4, CD5, CD7, CD8, CD20, CD25, CD30 and CD45RO markers. Ki-67 was used to evaluate the proliferative index.

RESULTS

Twenty-seven cases were primary, while 25 were secondary. Monoclonal viral integration was demonstrated in all atypical cases. Patterns resembling mycosis fungoides (MF) were found in 19 cases and anaplastic large-cell lymphoma (ALCL) in two cases. Fifteen cases had an atypical immunophenotype and expressed CD8. Primary cutaneous ATL had a longer MST (48 months) than the secondary cutaneous ATL (7 months) and the difference was statistically significant, but no statistically significant difference was found between the MST of CD8-positive and negative cases.

CONCLUSIONS

It is important to differentiate between primary and secondary cutaneous ATL and classify the cases histologically in order to better evaluate the prognosis. The two forms of primary cutaneous ATL, primary cutaneous smoldering and primary cutaneous tumoral (PCT), should also be identified. The smoldering type presented a longer survival (58 months) and histological aspects suggestive of better prognosis in contrast to the PCT type that had a shorter survival (20 months) and histological characteristics suggestive of worse outcome.

Manifestações cutâneas da infecção e das doenças relacionadas ao vírus linfotrópico de células T humanas do tipo 1

O vírus linfotrópico de células T humanas tipo 1 (HTLV-1) é um retrovírus encontrado em todo o mundo e, no Brasil, tem distribuição heterogênea com várias regiões consideradas de alta prevalência. Está relacionado com doenças graves e/ou incapacitantes, como a leucemia/linfoma de células T do adulto, com a doença neurológica conhecida como mielopatia associada ao HTLV-1/paraparesia espástica tropical, com a uveíte associada ao HTLV-1 e com a dermatite infecciosa. O risco para o aparecimento dessas doenças depende, principalmente, de fatores genéticos, da forma como a infecção foi adquirida e da carga proviral. Estima-se que até 10% dos infectados possam desenvolver alguma doença relacionada ao vírus ao longo da vida. O comprometimento da pele tem sido descrito tanto nas doenças relacionadas ao HTLV-1 quanto nos indivíduos portadores assintomáticos. Vários mecanismos são propostos para explicar as lesões da pele, seja pela presença direta do vírus em células, pela imunossupressão ou por resposta inflamatória que a infecção pelo vírus poderia desencadear. Dentre as manifestações dermatológicas mais freqüentes destacam-se a xerose, as dermatofitoses e as infecções bacterianas recorrentes. Neste artigo são revistos os principais aspectos referentes à infecção e às doenças relacionadas ao HTLV- 1, com ênfase na discussão das manifestações dermatológicas observadas nesse contexto.

HTLV type 1 genetic types among native descendants in Argentina

The province of San Salvador de Jujuy, located in the northwest of Argentina, is a highly endemic area for HTLV-1 infection and a foci of tropical spastic paraparesis/HTLV-1-associated myelopathy (HAM/TSP). Therefore, to better understand this, we carried out a genetic characterization of a large set of HTLV-1 strains (n = 65) of descendants of Amerindians from this region. The LTR and env regions were analyzed. The genetic analysis showed that all of these new HTLV-1 isolates from Argentina belong to the Transcontinental subgroup A of the HTLV-1a Cosmopolitan subtype, with the exception of three isolates that cluster within the Japanese subgroup B. Interestingly, the majority of the sequences from Jujuy province belonged to a distinct cluster within the Latin America Transcontinental subgroup, referred to here as the Jujuy subcluster, and were characterized by specific signatures in the LTR. Given that the samples analyzed in this study belong to the Amerindian population and the high prevalence of HTLV-1 in Jujuy in contrast to the low prevalence of this virus in the country, it could be that HTLV-1aA was spread in Argentina from the Amerindians to the cosmopolitan population. Moreover, this is the first report of an HTLV-1aB or Japanese subgroup in descendants of non-Japanese people in South America.

Retrospective study of the prevalence of human T-cell lymphotropic virus-type 1/2, HIV, and HBV in pregnant women in Argentina

This study shows first data on HTLV-1/2 seroprevalence among pregnant women in the non-endemic region of Argentina. In a retrospective study a representative sample (n = 3,143) of the pregnant women registered in the health public service in the province of Córdoba was evaluated. HTLV-1/2 seroprevalence was 0.191% +/- 0.0857 [IC 0.022-0.359]. This prevalence was 10 times higher in pregnant women than in blood donors [0.019 (4/21.183)]. The pregnant women would reflect the epidemiology of the general population more accurately since it constitutes a more heterogeneous group than that of blood donors. The prevalence of infection with HIV was 2.8 times higher than that of HTLV-1/2 (P < 0.05) and the presence of any of these two viruses was not a subrogating indicator of the presence of the other (Goodman and Kruskal's Tau coefficient = 0.0092). The prevalence of HBV was not significantly different from that of HTLV-1/2 (P > 0.05). We consider that it is necessary to carry out continuous studies in order to define the main risk factors for infection of these women. Thus, a decision could be made to apply the best policy in public health to prevent vertical transmission of the virus in Argentina.

Immunologic markers, uveitis, and keratoconjunctivitis sicca associated with human T-cell lymphotropic virus type 1

PURPOSE

To verify the occurrence of keratoconjunctivitis sicca (KCS) and human T-cell lymphotropic virus type 1 (HTLV-1) associated uveitis (HAU) and to evaluate the immunologic status related to HTLV-1.

DESIGN

Cross-sectional study.

METHODS

Ophthalmic examination (both eyes) and immunophenotyping of peripheral blood lymphocytes were performed in 207 infected asymptomatic blood donors (AS), 55 controls (NI), and 55 patients with HTLV-1 associated myelopathy (HAM/TSP). Examiner was masked to patient's serologic status.

RESULTS

KCS was more frequent in HAM/TSP (30/55, 54.5%) than in NI and AS (07/55, 12.7% and 42/207, 20.3%, respectively). Presence of lacrimal hyposecretion in KCS individuals was higher in the HAM/TSP group (P < .001) as compared with NI and AS. HAU was found in 1/55 (1.82%) of HAM/TSP patients and 4/207 (1.93%) of HTLV-1 seropositive donors. Higher levels of activated CD4(+) and CD8(+) T cells were observed in HAM/TSP. Patients with HAU displayed higher percentage of both CD4(+) HLA-DR(+) and CD8(+)HLA-DR(+) when compared with NI and AS without HAU.

CONCLUSIONS

Patients with HAM/TSP manifested more ophthalmologic symptoms than asymptomatic HTLV-1-infected individuals, with significantly higher KCS and immunologic alterations. Levels of activated CD8+ T cells could be used as a prognosis marker of inflammatory disease manifestation to follow-up AS individuals.

Human T lymphotropic virus type I/II infection: prevalence and risk factors in individuals testing for HIV in counseling centers from Southern Brazil

OBJECTIVE

The objective of this study was to ascertain the prevalence and to investigate risk factors for human T lymphotropic virus type I/II (HTLV I/II) infection among subjects who tested for HIV at three counseling centers in Porto Alegre, Brazil.

METHODS

The authors conducted a cross-sectional study in which subjects screened for HIV were tested for HTLV. Socioeconomic and demographic data, social and sexual behavior, history of having been breastfed, and past blood transfusion or drug use were gathered with a standardized questionnaire.

RESULTS

Among 2985 participants, 2.4% had HTLV infection confirmed (1.4% HTLV I). The risk increased with age, but there was no difference among genders. The multivariate model shows that injecting cocaine users were 5.2 (95% confidence interval, 2.5-10.7) times more likely to be HTLV I/II-positive than non-injecting cocaine users and HIV infection persisted as an independent risk factor.

CONCLUSION

Among persons presenting at HIV testing centers in Porto Alegre, Brazil, HTLV I was three times more common than HTLV II; injection drug use was the predominant mode of transmission.

Global epidemiology of HTLV-I infection and associated diseases

Epidemiologic aspects of human T-lymphotropic virus type I (HTLV-I) infection have been thoroughly studied over the course of approximately 25 years since its first description. The geographic distribution of the virus has been defined, with Japan, Africa, Caribbean islands and South America emerging as the areas of highest prevalence. The reasons for HTLV-I clustering, such as the high ubiquity in southwestern Japan but low prevalence in neighboring regions of Korea, China and eastern Russia are still unknown. The major modes of transmission are well understood, although better quantitative data on the incidence of transmission, and on promoting/inhibiting factors, are needed. Epidemiologic proof has been obtained for HTLV-I's causative role in major disease associations: adult T-cell leukemia (ATL), HTLV-associated myelopathy/tropical spastic paraparesis (HAM/TSP), HTLV-associated uveitis and infective dermatitis. However, more and better studies are needed for other apparent disease outcomes such as rheumatologic, psychiatric and infectious diseases. Since curative treatment of ATL and HAM/TSP is lacking and a vaccine is unavailable, the social and financial cost for the individual, his/her family and the health system is immense. For this reason, public health interventions aimed at counseling and educating high-risk individuals and populations are of paramount importance.

Human T cell lymphotropic virus type 1 infection and early neurologic development: a pilot study of 48 children

To determine whether human T cell lymphotropic virus type 1 (HTLV-1) infection is associated with delayed neurological development, we examined 48 Peruvian children with exposure to HTLV-1 who were identified at the Instituto Materno-Perinatal. Compared with 38 HTLV-1-seronegative children, the 10 seropositive children did not have higher rates of neurodevelopmental delay. Long-term follow-up is planned.