Advances in preventive vaccine development against HTLV-1 infection: A systematic review of the last 35 years.

Introduction: The Human T-lymphotropic virus type 1 (HTLV-1) was the first described human retrovirus. It is currently estimated that around 5 to 10 million people worldwide are infected with this virus. Despite its high prevalence, there is still no preventive vaccine against the HTLV-1 infection. It is known that vaccine development and large-scale immunization play an important role in global public health. To understand the advances in this field we performed a systematic review regarding the current progress in the development of a preventive vaccine against the HTLV-1 infection. Methods: This review followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA®) guidelines and was registered at the International Prospective Register of Systematic Reviews (PROSPERO). The search for articles was performed in PubMed, Lilacs, Embase and SciELO databases. From the 2,485 articles identified, 25 were selected according to the inclusion and exclusion criteria. Results: The analysis of these articles indicated that potential vaccine designs in development are available, although there is still a paucity of studies in the human clinical trial phase. Discussion: Although HTLV-1 was discovered almost 40 years ago, it remains a great challenge and a worldwide neglected threat. The scarcity of funding contributes decisively to the inconclusiveness of the vaccine development. The data summarized here intends to highlight the necessity to improve the current knowledge of this neglected retrovirus, encouraging for more studies on vaccine development aiming the to eliminate this human threat. Systematic review registration: https://www.crd.york.ac.uk/prospero, identifier (CRD42021270412).

Role of the Microbiome in Aedes spp. Vector Competence: What Do We Know?

Aedes aegypti and Aedes albopictus are the vectors of important arboviruses: dengue fever, chikungunya, Zika, and yellow fever. Female mosquitoes acquire arboviruses by feeding on the infected host blood, thus being able to transmit it to their offspring. The intrinsic ability of a vector to infect itself and transmit a pathogen is known as vector competence. Several factors influence the susceptibility of these females to be infected by these arboviruses, such as the activation of the innate immune system through the Toll, immunodeficiency (Imd), JAK-STAT pathways, and the interference of specific antiviral response pathways of RNAi. It is also believed that the presence of non-pathogenic microorganisms in the microbiota of these arthropods could influence this immune response, as it provides a baseline activation of the innate immune system, which may generate resistance against arboviruses. In addition, this microbiome has direct action against arboviruses, mainly due to the ability of Wolbachia spp. to block viral genome replication, added to the competition for resources within the mosquito organism. Despite major advances in the area, studies are still needed to evaluate the microbiota profiles of Aedes spp. and their vector competence, as well as further exploration of the individual roles of microbiome components in activating the innate immune system.

Silencioso e negligenciado: o que se sabe após quatro décadas do descobrimento do HTLV-1? / Silent and neglected: what is known after four decades of the discovery of the HTLV-1? / Silencioso y descuidado: ¿qué se sabe después de cuatro décadas del descubrimiento del HTLV-1?

O vírus linfotrópico T humano tipo 1 (HTLV-1) foi o primeiro retrovírus humano descoberto, descrito pela primeira vez há 41 anos. Esse retrovírus está associado ao desenvolvimento de duas doenças graves: a leucemia/linfoma de células T do adulto (ATLL) e a mielopatia associada ao HTLV-1/paraparesia espástica tropical (HAM/TSP). Este trabalho teve como objetivo analisar as atualizações sobre o HTLV-1, destacando os aspectos clínicos, os avanços e as limitações no tratamento e na prevenção da infecção pelo HTLV-1. Para isso, foi realizada uma revisão integrativa, por meio de coleta de dados nas plataformas PubMed, LILACS e SciELO, entre março e abril de 2021. Foram incluídos 61 artigos de diferentes países. O Brasil foi o país com maior número de publicações na área: 12. Os resultados obtidos mostram que existem avanços importantes no que diz respeito ao tratamento e à prevenção da infecção pelo HTLV-1. No entanto, a falta de estudos específicos sobre o vírus, que abordem os aspectos clínicos da infecção, foi um fator limitante para este estudo, o que reforça a necessidade de investimento em novas pesquisas sobre o tema.

The Human T-lymphotropic Virus 1 (HTLV-1) was the first human retrovirus discovered, described for the first time 41 years ago. This retrovirus is associated with the development of two serious diseases: adult T-cell leukemia/lymphoma (ATLL) and tropical spastic paraparesis/HTLV-1-associated myelopathy (HAM/TSP). This study aimed to analyze the updates about HTLV-1, highlighting the clinical aspects, advances, and limitations in the treatment and prevention of HTVL-1 infection. To this end, an integrative review was carried out, with data collection on PubMed, LILACS, and SciELO platforms, between March and April 2021. A total of 61 articles from different countries were included. Brazil was the country with the largest number of publications in the area: 12. The results showed effective advances regarding treating and preventing HTLV-1 infection. However, the lack of specific studies about the virus, which address the clinical aspects of the infection, was a limiting factor for this study, which reinforces the need for investment in new research about this topic.

El virus linfotrópico T tipo 1 humano (HTLV-1) fue el primer retrovirus humano descubierto y se describió por primera vez hace 41 años. Este retrovirus está asociado con el desarrollo de dos enfermedades graves: leucemia/linfoma de células T del adulto (ATLL) e mielopatía asociada a HTLV-1/paraparesia espástica tropical (HAM/TSP). Este estudio tuvo como objetivo analizar las actualizaciones sobre HTLV-1, destacando los aspectos clínicos, los avances y limitaciones en el tratamiento y prevención de la infección por HTLV-1. Para ello, se realizó una revisión integradora, a través de la recolección de datos en las plataformas PubMed, LILACS y SciELO entre marzo y abril de 2021. Se incluyeron 61 artículos de diferentes países. Brasil fue el país con mayor número de publicaciones en el área: 12. Los resultados obtenidos muestran que existen avances efectivos en cuanto al tratamiento y prevención de la infección por HTLV-1. Sin embargo, la falta de estudios específicos sobre el virus que aborden los aspectos clínicos de la infección fue un factor limitante para el presente estudio, lo que refuerza la necesidad de invertir en nuevas investigaciones sobre este virus.