RESUMO
Non-human primates are considered to be likely sources of viruses that can infect humans and thus pose a significant threat to human population. This is well illustrated by some retroviruses, as the simian immunodeficiency viruses and the simian T lymphotropic viruses, which have the ability to cross-species, adapt to a new host and sometimes spread. This leads to a pandemic situation for HIV-1 or an endemic one for HTLV-1. Here, we present the available data on the discovery, epidemiology, cross-species transmission and molecular virology of the recently discovered HTLV-3 and HTLV-4 deltaretroviruses, as well as the simian foamy retroviruses present in different human populations at risk, especially in central African hunters. We discuss also the natural history in humans of these retroviruses of zoonotic origin (magnitude and geographical distribution, possible inter-human transmission). In Central Africa, the increase of the bushmeat trade during the last decades has opened new possibilities for retroviral emergence in humans, especially in immuno-compromised persons.
Assuntos
Infecções por Deltaretrovirus/epidemiologia , Infecções por Deltaretrovirus/veterinária , HIV-2/fisiologia , Vírus Linfotrópico T Tipo 3 Humano/fisiologia , Vírus Espumoso dos Símios/fisiologia , África Central/epidemiologia , Animais , Ásia/epidemiologia , Infecções por Deltaretrovirus/transmissão , Infecções por Deltaretrovirus/virologia , Transmissão de Doença Infecciosa/prevenção & controle , Produtos do Gene tax/genética , HIV-2/patogenicidade , Haplorrinos , Especificidade de Hospedeiro , Vírus Linfotrópico T Tipo 3 Humano/patogenicidade , Humanos , Isoformas de Proteínas/genética , Vírus Espumoso dos Símios/patogenicidade , Zoonoses/epidemiologia , Zoonoses/transmissão , Zoonoses/virologiaRESUMO
Human T-lymphotropic virus type 1 (HTLV-1) and type 2 (HTLV-2) were discovered approximately 30 years ago and they are associated with various lymphoproliferative and neurological diseases. The estimated number of infected people is 10-20 million worldwide. In 2005, two new HTLV-1/HTLV-2-related viruses were detected, HTLV-3 and HTLV-4, from the same geographical area of Africa. In the last 4 years, their complete genomic sequences were determined and some of their characteristic features were studied in detail. These newly discovered retroviruses alongside their human (HTLV-1 and -2) and animal relatives (simian T-lymphotropic virus type 1-3) are reviewed. The potential risks associated with these viruses and the potential antiretroviral therapies are also discussed.
