Human Tcell lymphotropic virus type

III The name given by workers at the National Cancer Institute, USA to early isolates of the virus causing AIDS. Subsequently found to be identical to the French isolate, LAV LAI, and renamed Human immunodeficiency virus type 1 (HIV-1).

human T-lymphotropic virus type 1 (HTLV-1) A strain of Primate T-lym-photropc virus I in the genus Deltaretrovirus. An exogenous retrovirus isolated in 1980 from a case of adult T-cell leukemia (ATL), a disease which is endemic in Japan, the Caribbean, Melanesia, South America, Iran and parts of Africa. There is strong seroepidemio-logical evidence that HTLV-I is the cause of ATL. In 1985, HTLV-1 was also found to be associated with a slowly progressive myelopathy known in the Caribbean as tropical spastic paraparesis and in Japan as HTLV-1-associated myelopathy. This disease is now termed HTLV-1-asso-ciated myelopathy/tropical spastic paraparesis (HAM/TSP). It is believed to be immunologically mediated and is more frequently found in women than in men. The latent period between infection and disease is years to decades for ATL, but usually 2-4 years for HAM/TSP. The HTLV-I genome is 9032 nucleotides long and contains gag, pro, pol and env genes as well as long terminal repeats (LTRs). The genome also contains a pX sequence between the env gene and the 3' LTR that includes two overlapping regulatory genes: tax, the product of which (p40tax) transactivates proviral transcription; and rex, the product of which (p27rex) modulates RNA processing. Two other proteins of unknown function, also encoded in this region of the genome, have been identified in infected cells. Cell-free HTLV-2 particles have extremely low infectivity in vitro, but co-cultivation of virus-producing cells can be used to transmit the virus to a variety of cells including human T and B lymphocytes, fibroblasts and epithelial cells, and cells from other species such as hamster, monkey, rat and rabbit, but not mice. In infected humans, only CD4+ T cells appear to be infected. Most human transmission in the past was through blood transfusions. With the development of ELISA tests for the presence of p21e antibodies, blood screening has been introduced in most developed countries and HTLV-positive blood units are not used. Transmission may also occur through sexual contact and from mother to child during breast-feeding. HTLV-1 proviral DNA has been detected in an Andean mummy about 1500 years old and provides evidence of prehistoric migration from Asia to South America.

Kaplan JE and Khabbaz RF (1993) Rev Med Virol 3, 137

Li H-C et al (1999) Nature, Medicine 5, 1428 Salemi M et al (1998) Virology 246, 277 Sugamura K and Hinuma Y (1993) In The Retroviridae, vol. 2, edited by JA Levy. New York: Plenum Press, p. 399 Vidal AU et al (1994) J Gen Virol 75, 3655

human T-lymphotropic virus type 2 (HTLV-2) A strain of Primate T-lym-photropic virus 2 in the genus Deltaretrovirus. Originally isolated from an immortalized T-cell line (MoT) established from the spleen of a patient with a T-cell variant of hairy-cell leukemia. The genome is 8952 bases long, with a similar organization but only 60% homology to that of HTLV-1. No clear association with any human disease has been found to date, and the virus does not appear to be etiologically linked to hairy-cell leukemia. There are two subtypes, known as HTLV-2a and HTLV-2b, based upon nucleotide sequences, of the env gene, but further subdivision has been found using LTR sequences, which are more diverse. High incidence of HTLV-2 (up to 10% of the population) has been found in certain native American Indian populations in which the infection appears to be endemic. Outside of these endemic foci, high rates of HTLV-2 infection have only been found in intravenous drug users in North America, Italy and Spain, and in the Pygmies in Central Africa.

Hall WW et al (1994) Semin Virol 5, 165 Lewis MJ et al (2000) Virology 271, 142 Switzer WM et al (1995) J Virol 69, 621

Human torovirus (HuTV) See Torovirus.

human wart virus Synonym for Human papillomavirus.

humoral immunity Immunity conferred by antibodies in extracellular fluids including the serum and lymph.

Humpty Doo virus (HDOOV) An unas-signed vertebrate rhabdovirus. Isolated from the mosquito, Culicoides marksi, in Beatrice Hill, Northern Australia. Not associated with disease in humans.

Standfast HA et al (1984) Aust J Biol Sci 37, 351

huncho virus (HUAV) Does not exist. The name appears in the 7th ICTV Report due to a misprint. It should read Huacho virus (HUAV).

hundestaupe Synonym for Canine distemper virus.

hundskrankheit (German: = 'dog disease') Synonym for phlebotomus fever. So called because the conjunctivae become so markedly infected that they resemble the eyes of a bloodhound. See phleboto-mus fever viruses.

HV-114 virus (HV-114) A strain of Hantaan virus in the genus Hantavirus.

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