Search Results (149)

Porcine lymphotropic herpesviruses -1, -2, and -3 (PLHV-1, PLHV-2, and PLHV-3) are gammaherpesviruses that are widespread in pigs. These viruses are closely related to the human pathogens Epstein–Barr virus (EBV) and Kaposi sarcoma-associated herpesvirus (KSHV), both of which are known to cause severe diseases in humans. To date, however, no definitive association has been established between PLHVs and any disease in pigs. With the growing interest in xenotransplantation as a means to address the shortage of human organs for transplantation, the safety of using pig-derived cells, tissues, and organs is under intense investigation. In preclinical trials involving pig-to-nonhuman primate xenotransplantation, another porcine herpesvirus—porcine cytomegalovirus, a porcine roseolovirus (PCMV/PRV)—was shown to be transmissible and significantly reduced the survival time of the xenotransplants. In the present study, we examined donor pigs and their respective baboon recipients, all of which were part of preclinical pig heart xenotransplantation studies, for the presence of PLHV. PLHV-1, PLHV-2, and PLHV-3 were detected in nearly all donor pigs; however, no evidence of PLHV transmission to the baboon recipients was observed. Full article

Human T-cell lymphotropic virus (HTLV), a retrovirus associated with severe conditions such as leukemia/lymphoma and myelopathy, exhibits variable global prevalence, with higher rates observed in regions such as northeastern Brazil and sub-Saharan Africa. While intrauterine transmission can occur via viral expression in placental tissue and contact with umbilical cord blood, the predominant route is vertical transmission through breastfeeding. Diagnostic testing, particularly serological screening with ELISA and confirmatory methods such as Western blot and PCR, is essential for early detection during pregnancy. The implementation of prenatal screening programs, as seen in Japan and Brazil, has proven effective in reducing vertical transmission by guiding interventions such as breastfeeding cessation in infected mothers. Beyond clinical implications, the psychosocial impact on affected pregnant women highlights the need for an interdisciplinary approach. Although the association between HTLV infection and adverse obstetric outcomes remains controversial, studies suggest increased risks of preterm birth, low birth weight, and other neonatal complications. Given the importance of early diagnosis and prevention, universal prenatal screening protocols represent a critical strategy to reduce viral transmission and its long-term consequences. Full article

Human T-lymphotropic virus 1 (HTLV-1) infection has been associated with inflammatory, autoimmune, and lymphoproliferative diseases with a wide spectrum of clinical manifestations. Among patients with inflammatory rheumatological disease manifestations, cases of rheumatoid arthritis, Sjögren’s syndrome, polymyositis, and fibromyalgia, among others, have been reported. Another common feature of rheumatological diseases is the presence of joint manifestations, such as arthralgia and arthritis. In the present study, we sought to determine the laboratory profile and clinical rheumatological manifestations of people living with HTLV-1/2 residing in a metropolitan area in the Brazilian Amazon. A total of 957 individuals were screened for HTLV-1/2 infection by enzyme-linked immunosorbent assay (ELISA), and samples from seropositive individuals were subjected to infection confirmation by Western blotting or quantitative polymerase chain reaction (qPCR). Individuals with confirmed HTLV-1 and HTLV-2 infection were clinically evaluated for signs and symptoms of rheumatological diseases. Of the 957 individuals tested, 69 were positive for HTLV-1/2 infection, with 56 confirmed cases of HTLV-1 infection (5.9%), 12 of HTLV-2 infection (1.2%), and 1 classified as undetermined (0.1%). After clinical screening, 15 infected individuals with complaints suggestive of rheumatological disease were selected for evaluation by a rheumatologist (11 with HTLV-1 infection (1.1%) and 4 with HTLV-2 infection (0.4%)). The predominant pain pattern was symmetrical polyarthralgia, with large joints predominantly being affected. The diseases diagnosed were psoriatic arthritis, osteoarthritis, fibromyalgia, and regional pain syndromes. Antinuclear antibody (ANA) positivity was observed in two patients. Our findings confirm that HTLV-1 infection is associated with rheumatological disease manifestations and highlight the novel finding of cases of HTLV-2 infection in patients with rheumatoid arthritis symptoms. Full article

This descriptive, observational, cross-sectional study evaluated HTLV-1 and HTLV-2 infections in Ananindeua, northern Brazil. Individuals were screened for anti-HTLV-1/2 using ELISA (Murex HTLV-I + II, DiaSorin). Reactive or indeterminate samples underwent confirmation via Western blot (HTLV Blot 2.4 kit, MP Diagnostics) and/or RT-qPCR. A questionnaire examined behavioral and risk factors for HTLV-1/2 infection. HTLV-positive individuals received counseling, nurse follow-up, and specialized medical care. Among the 228 individuals investigated, 6 (2.7%) were infected with HTLV-1: 4 men (66.67%) and 2 women (33.33%), aged 51–73 years. The only significant risk factor observed was blood transfusion. Additionally, 80 other individuals residing in the municipality of Ananindeua independently visited the laboratory for an HTLV-1/2 diagnosis. Among them, 23 were diagnosed with HTLV-1 infection, and 1 with HTLV-2. Among the 30 positive individuals, 80% were asymptomatic, while 20% exhibited clinical manifestations associated with HTLV infection, including HAM and Sézary syndrome. These results indicate a notable prevalence of HTLV-1 infection in the municipality of Ananindeua emphasizing the significance of diagnosing the infection to assess its prevalence across the country accurately. Full article

Human T-lymphotropic viruses (HTLVs) are deltaretroviruses infecting millions of individuals worldwide, with HTLV-1 and HTLV-2 being the most widespread and clinically relevant types. HTLV-1 is associated with severe diseases such as adult T-cell leukemia/lymphoma (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), while HTLV-2 shows a lower pathogenic potential, with occasional links to neurological disorders. HTLV-3 and HTLV-4, identified in Central Africa, remain poorly characterized but are genetically close to their simian counterparts, indicating recent zoonotic transmission events. HTLVs replicate through a complex cycle involving cell-to-cell transmission and clonal expansion of infected lymphocytes. Viral persistence is mediated by regulatory and accessory proteins, notably Tax and HBZ in HTLV-1, which alter host cell signaling, immune responses, and genomic stability. Integration of proviral DNA into transcriptionally active regions of the host genome may contribute to oncogenesis and long-term viral latency. Differences in viral protein function and intracellular localization contribute to the distinct pathogenesis observed between HTLV-1 and HTLV-2. Geographically, HTLV-1 shows endemic clusters in southwestern Japan, sub-Saharan Africa, the Caribbean, South America, and parts of the Middle East and Oceania. HTLV-2 is concentrated among Indigenous populations in the Americas and people who inject drugs in Europe and North America. Transmission occurs primarily via breastfeeding, sexual contact, contaminated blood products, and, in some regions, zoonotic spillover. Diagnostic approaches include serological screening (ELISA, Western blot, LIA) and molecular assays (PCR, qPCR), with novel biosensor and AI-based methods under development. Despite advances in understanding viral biology, therapeutic options remain limited, and preventive strategies focus on transmission control. The long latency period, lack of effective treatments, and global neglect complicate public health responses, underscoring the need for increased awareness, research investment, and targeted interventions. Full article

Contrary to extensively studied porcine alphaherpesvirus (SuHV-1/PRV), betaherpesvirus (SuHV-2/PCMV) and Gammaherpesvirinae (SuHV-3/PLHV-1, SuHV-4/PLHV-2, SuHV-5/PLHV-3) infections remain unexplored in the swine population in Poland. The aim of this study was to characterise the prevalence of infections and local strains from each major herpesvirus subfamily on a large-scale weaner farm located in Poland. Nasal swabs collected from pigs at 6, 8 and 10 weeks of age were tested for the presence of herpesvirus infections using nested PCR specific to the pan-herpesvirus DNA polymerase (DPol) gene. The amplicons obtained from the positive samples were sequenced using the Sanger method. In total, 60% of the pigs were positive for herpesviruses, including 35.6% for porcine cytomegalovirus (SuHV-2/PCMV) and 24.4% for porcine lymphotropic herpesvirus type 1 (SuHV-3/PLHV-1). The infection rate was lowest in 6-week-old pigs—20% (6.7%—PCMV, 13.3%—PLHV-1) in comparison to 8-week-old—80% (53.3%—PCMV, 26.7% PLHV-1)—and 10-week-old pigs—80% (46.7%—PCMV, 33.3%—PLHV-1). No correlation between PCMV and PLHV-1 infections and coinfections with IAV, PRV1 or PRRSV was observed. Sequence analysis of both PLHV-1 and PCMV showed high genetic uniformity. Additionally, PLHV-1 isolates showed a close relationship to strains isolated from wild boar in Poland and pigs in Germany in recent years. In summary, our study confirmed the presence of both PLHV-1 and PCMV infections occurring early in piglet development, probably after passive immunity cessation. Full article

Human T-cell lymphotropic virus type 1 (HTLV-1) infection poses significant challenges to maternal and neonatal health, particularly in endemic regions. Vertical transmission, which occurs most commonly through prolonged breastfeeding and rarely during pregnancy, or childbirth, perpetuates the virus within families. This observational, retrospective study analyzed HTLV-1-infected and uninfected pregnant women admitted for delivery at a university maternity hospital in Salvador, Brazil (2020–2022). Medical records provided sociodemographic, clinical, and laboratory data. The HTLV-1 infection rate was 4.61 per 1000 deliveries. The sociodemographic characteristics were similar between infected (n = 17) and uninfected (n = 34) women. HTLV-1-positive women had higher rates of unplanned and undesired pregnancies. Adverse pregnancy outcomes were frequent in both groups (94.1% vs. 91.2%), but metabolic disorders and hypertension/eclampsia were more common among the infected women. Preterm birth and postpartum complications were also more frequent (17.6% vs. 5.9%, respectively), although the difference was not statistically significant. Breastfeeding initiation within the first hours of life was lower among exposed newborns (28.6% vs. 70%; p = 0.013). Neonatal characteristics did not differ significantly between the groups. These findings highlight critical gaps in reproductive health awareness and barriers to accessing preventive interventions. Further research on therapeutic strategies is urgently needed to support the World Health Organization’s (WHO) goal of eliminating HTLV-1 vertical transmission by 2030. Full article

The human T-cell lymphotropic viruses of type 1 and 2 (HTLV 1/2) are retroviruses with estimations of 10 million people infected worldwide. HTLV 1/2 viruses are endemic in South America where Indigenous and Afro American populations are considered of high risk. Although several case reports of HTLV 1/2 associated pathologies and some prevalence studies have been reported in Ecuador, the country lacks a national surveillance and control program, and no screening of blood or organ donors is currently done. We discuss the problems associated to HTLV 1/2 in Ecuador and propose a strategy to improve a surveillance and control program. Full article

Background: Flower-shaped nuclei in plasma cells are rare in multiple myeloma. Case presentation: We report on an 88-year-old male who presented with a mass lesion in the clavicular region. A biopsy of the mass revealed an increase in mature plasma cells with round nuclei. In contrast, a bone marrow examination showed increased plasma cells with flower-shaped nuclei. The patient tested negative for human T-lymphotropic virus type-1 and was diagnosed with multiple myeloma. Conclusions: While multiple myeloma is known for intra-tumor heterogeneity, reports of morphological heterogeneity based on the site of tumor sampling are limited. In this case, the presence of plasma cells with flower-shaped nuclei enabled the identification of site-dependent morphological tumor heterogeneity. Full article

Introduction: Human T-cell lymphotropic virus type 1 (HTLV-1) is endemic to Brazil, and there is still no specific treatment for these patients. The literature shows that few studies have described the cognitive impairment associated with an HTLV-1 infection, with none of them examining the population of Salvador, where there are approximately forty thousand people infected with the virus. Objectives: To determine the prevalence of cognitive impairment among individuals with HTLV-1. In addition, investigate whether sociodemographic aspects, time since the diagnosis of infection, and the diagnosis of HTLV-Associated Myelopatia/Tropical Spastic Paraparesis (HAM/TSP) or depression are associated with cognitive impairment in this population. Methods: This was an observational, cross-sectional study that consisted of consecutively approaching 100 HTLV-1 patients during outpatient care at a referral center followed by the administration of three questionnaires— the Mini Mental State Examination (MMSE), the Montreal Cognitive Assessment (MoCA), and Beck’s Depression Inventory. Results: The prevalence of cognitive impairment found was 71% using the MMSE and 82% using the MoCA. There was a statistically significant association between the cognitive dysfunction and the variables of age and education according to the MoCA analysis but not the MMSE data. Diagnosis of HAM/TSP was correlated with cognitive impairment using the MMSE but not the MoCA. The prevalence of depression was 20%, and there was no association between cognitive impairment and depressive symptoms in these patients. Conclusions: The findings of this study demonstrate a correlation between cognitive dysfunction and HTVL-1 infection, with a more evident involvement of executive functions and memory. Larger studies are needed to clarify the association between cognitive dysfunction, age, education, and the diagnosis of HAM/TSP. Full article

This is the first systematic review and meta-analysis to estimate the prevalence of human T-lymphotropic virus 1 and 2 (HTLV-1 and 2) infections among immigrants and refugees worldwide. PubMed/MEDLINE, Scopus, EMBASE, Web of Science, and Virtual Health Library (VHL) databases were searched for studies published from their inception to 6 January 2023. A meta-analysis using a generalized linear mixed model with a random effect was performed for HTLV-1 and HTLV-2. Subgroup analyses were performed based on the decade of study, sample size, confirmatory methods, region of study, risk group, and region of origin. Of the 381 studies initially identified, 21 were included. The pooled prevalence of HTLV-1 and HTLV-2 was 1.28% (95% CI: 0.58, 2.81) and 0.11% (95% CI: 0.04, 0.33), respectively. HTLV-1 prevalence differed significantly by region of origin, with the highest prevalence among those from the Western Pacific Region (7.27%; 95% CI: 2.94, 16.83). The subgroup analysis also showed significant differences between the estimates of HTLV-1 considering the decade of study, sample size, and region of study. For HTLV-2, significant differences were shown in relation to sample size, confirmatory methods, and risk group. The higher HTLV-1 prevalence found deserves public health attention in immigrant and refugee-receiving non-endemic countries. Full article

Adult T-cell Leukemia/Lymphoma (ATLL) is a rare but aggressive malignancy associated with the human T-cell lymphotropic virus type 1 (HTLV-1). ATLL is a challenging malignancy characterized by its aggressive nature and poor prognosis. Despite advancements in treatment, relapse rates remain high. Donor lymphocyte infusion (DLI) is a promising therapeutic option post-hematopoietic stem cell transplantation (HSCT) to prevent relapse. However, the prophylactic use of DLI in ATLL patients remains underexplored. We report the case of a 45-year-old female diagnosed with ATLL. Following induction chemotherapy and successful HSCT, a modified prophylactic DLI regimen was administered, consisting of gradually increasing doses of donor lymphocytes. The patient demonstrated a favorable response with no significant graft-versus-host disease (GVHD) and maintained remission over a 40-month follow-up period, suggesting a potential benefit of this approach. This case highlights the potential efficacy and safety of modified prophylactic DLI in ATLL patients, warranting further investigation. Our findings suggest that modified prophylactic DLI is a viable option for ATLL patients post-HSCT, offering a balance between efficacy and safety. Future research should focus on optimizing DLI protocols and exploring biomarkers for response prediction. Full article

HTLV-1-associated Myelopathy/Tropical Spastic Paraparesis (HAM/TSP) is a progressive non-remitting and incapacitating disease more frequently seen in women and with a patchy worldwide distribution. HAM/TSP develops in a small percentage of HTLV-1-infected individuals during their lifetime and etiologic factors for disease progression are still unclear. This study aims to describe the first case series of the progression of HAM/TSP in relation to pregnancy. Between January and March of 2012, we reviewed medical charts of women with HAM/TSP currently enrolled in the HTLV-1 cohort at the institute of tropical medicine of Cayetano Heredia University. Inclusion criteria included having a diagnosis of HAM/TSP according to the WHO guidelines and self-reported initial symptoms of HAM/TSP during pregnancy or within six months of delivery. Fifteen women reported having had symptoms compatible with HAM/TSP within four months of delivery. Among them, ten women had no symptoms before pregnancy and reported gait impairment after delivery. Five women with mild gait impairment before pregnancy noticed a worsening of their symptoms after delivery. Symptoms worsened after successive pregnancies. Recent studies have shown that HTLV-1 infection induces a strong T cell-mediated response and that the quality of this response plays a role in HAM/TSP pathogenesis. The relative immunosuppression during pregnancy, including blunting of the T-cell response, might allowed in certain women enhanced replication of HTLV-1 and disease progression in the postpartum. This is the first study looking specifically at HAM/TSP and pregnancy and the number of cases is remarkable. Further prospective studies of HTLV-1-infected women assessing immune markers during pregnancy are warranted. Breastfeeding was the main route of transmission. Strategies to prevent vertical transmission need to be evaluated in HTLV-1 endemic countries of Latin America. Full article

Human T-cell lymphotropic virus (HTLV) infection affects over ten million people worldwide, but there is no effective treatment so far. This review describes the virological, immunological, and clinical outcomes of antiretroviral therapy (ART) in people with HTLV infection. This systematic review followed PRISMA reporting guidelines and was registered in PROSPERO: CRD42022350076. The Newcastle–Ottawa Scale, adapted for cross-sectional studies, and Rob-2 were used to assess the methodological quality of these studies. Systematic searches were conducted in the Medline (PubMed), Scopus (Elsevier), Cochrane Library, and Web of Science (Clarivate Analytics) databases. We retrieved data from eight methodologically diverse articles on treatment of patients infected by HTLV-1 or HTLV-2 alone, or coinfected by HIV-1, who received Raltegravir, Tenofovir, Lamivudine, or Zidovudine. The proviral load decreased in three out of seven studies over 4 to 48 weeks of antiretroviral use. Cellular immune response (CD4, CD8, CD25, CD69, and CD71 cells) was evaluated in six studies. While no significant clinical improvement was observed, all studies reported clinical stability during treatment. Despite the demonstrated antiviral activity of ART, in vitro, clinical improvement was not proven. Most studies showed disease stability during ART use, suggesting potential clinical benefits. There is a need of larger, well-controlled trials to define the role of ART in the treatment of HTLV infection. Full article

Detection methods have been developed to prevent transmission of zoonotic or xenozoonotic porcine viruses after transplantation of pig organs or cells to the recipient (xenotransplantation). Eleven xenotransplantation-relevant viruses, including porcine cytomegalovirus, porcine roseolovirus (PCMV/PRV), porcine lymphotropic herpesviruses -1, -2, -3 (PLHV-1, 2, 3), porcine parvovirus (PPV), porcine circovirus 2, 3, 4 (PCV2, 3, 4), hepatitis E virus genotype 3 (HEV3), porcine endogenous retrovirus-C (PERV-C), and recombinant PERV-A/C have been selected. In the past, several pig breeds, minipigs, and genetically modified pigs generated for xenotransplantation had been analyzed using these methods. Here, spleen, liver, and blood samples from 10 German slaughterhouse pigs were screened using both PCR-based and immunological assays. Five viruses: PCMV/PRV, PLHV-1, PLHV-3, and PERV-C, were found in all animals, and PCV3 in one animal. Some animals were latently infected with PCMV/PRV, as only virus-specific antibodies were detected. Others were also PCR positive in the spleen and/or liver, indicative of an ongoing infection. These results provide important information on the viruses that infect German slaughterhouse pigs, and together with the results of previous studies, they reveal that the methods and test strategies efficiently work under field conditions. Full article