Human immunodeficiency virus type 2

Human immunodeficiency virus type 2
Name	Human immunodeficiency virus type 2
Familia	Retroviridae
Genus	Lentivirus

Contents

Human immunodeficiency virus type 2 is a lentiviral pathogen first characterized in the late 20th century that causes an acquired immunodeficiency syndrome clinically similar to infections caused by other lentiviruses. It was identified during molecular and serologic studies conducted by investigators associated with institutions such as Pasteur Institute, Centers for Disease Control and Prevention, World Health Organization, and research groups collaborating with universities like University of Oxford, Harvard University, and University of Lagos. Early reports appeared in journals and conferences attended by members of organizations including National Institutes of Health, Royal Society, and research consortia linked to Institut Pasteur de Dakar.

Virology and genetic classification

HIV-2 is a member of the Lentivirus genus within the family Retroviridae and is genetically closer to simian immunodeficiency viruses characterized in West Africa than to HIV-1 strains analyzed by teams at Wellcome Trust, Sanger Institute, and Cold Spring Harbor Laboratory. Molecular phylogenetics performed by groups at Max Planck Society and French National Centre for Scientific Research classify HIV-2 into multiple groups (A–H) based on divergence identified in sequence data produced using equipment from Illumina and Thermo Fisher Scientific. The viral genome encodes structural proteins gag, pol, env and accessory proteins studied in structural work at European Molecular Biology Laboratory and MIT, with envelope glycoprotein variation influencing tropism reported by investigators affiliated with Karolinska Institutet and Johns Hopkins University. Functional assays developed in laboratories at Massachusetts General Hospital and UCL have delineated replication kinetics and cell entry pathways that intersect with host receptors characterized in work from Stanford University and University of Cambridge.

The highest prevalence of HIV-2 is documented in countries of West Africa, notably regions studied by researchers from Senegal, Guinea-Bissau, Cape Verde, and The Gambia, with historical patterns traced through collaborations involving Institut Pasteur de Dakar and national public health agencies like Ghana Health Service and Nigeria Centre for Disease Control. International surveillance reported by World Health Organization and UNAIDS indicates sporadic cases in Europe and the Americas, linked to migration and travel through hubs such as Lisbon, Madrid, Paris, London, and port cities like New York City and Rio de Janeiro. Epidemiologic models developed at Imperial College London and Columbia University describe transmission dynamics influenced by urbanization in metropolises like Abidjan, Dakar, and Bissau and affected populations studied by NGOs such as Médecins Sans Frontières and Red Cross.

HIV-2 transmits via routes documented in clinical and field investigations by teams at Karolinska Institutet, University of Nairobi, and McGill University: sexual contact, parenteral exposure, and vertical transmission during childbirth or breastfeeding, with transmission dynamics examined alongside studies from Bill & Melinda Gates Foundation–funded programs. Viral entry mechanisms engage host receptors that were characterized in cell biology studies at Yale University and University of California, San Francisco, and immunopathogenesis reflects CD4+ T cell depletion described in work from Peter Medawar-influenced immunology groups at University of Oxford and University College London. Comparative pathogenesis papers from Institut Pasteur and NIH laboratories report slower disease progression and lower plasma viremia for many HIV-2 infections versus HIV-1, with exceptions noted in cohorts followed by King's College London and University of Barcelona.

Clinically, HIV-2 infection can produce opportunistic infections and AIDS-defining illnesses cataloged in case series from hospitals affiliated with Charité – Universitätsmedizin Berlin, Hôpital Fann, and Addenbrooke's Hospital. Time to immunodeficiency varies in cohort studies by University of Lisbon and University of Bordeaux. Laboratory diagnosis utilizes serologic assays and nucleic acid amplification tests developed by companies and laboratories such as Abbott Laboratories, Roche Diagnostics, and research groups at Institut Pasteur. Differential diagnosis and confirmatory testing are informed by guidelines from World Health Organization, European Centre for Disease Prevention and Control, and national bodies including Public Health England and Centers for Disease Control and Prevention.

Antiretroviral therapy regimens effective against HIV-2 have been assessed in clinical trials coordinated by institutions such as University of Coimbra, University of Nairobi, and multicenter networks supported by European AIDS Clinical Society and International AIDS Society. HIV-2 shows intrinsic resistance to non-nucleoside reverse transcriptase inhibitors identified in pharmacology studies at University of Cambridge and University of California, San Diego, and resistance mutations in protease and reverse transcriptase genes have been documented by surveillance efforts at Monash University and Pasteur Institute. Treatment guidelines from World Health Organization and national programs like National Health Service integrate evidence from randomized trials at Hopkins Clinical Research Network and cohort analyses at University of Ghana.

Prevention strategies draw on successful programs and policy frameworks developed by UNAIDS, World Health Organization, Bill & Melinda Gates Foundation, and national ministries of health such as Ministry of Health (Senegal), incorporating testing, counseling, antiretroviral prophylaxis, maternal-child health initiatives in collaboration with UNICEF, and harm-reduction programs run by NGOs including Médecins Sans Frontières and Population Services International. Surveillance, contact tracing, and education campaigns modeled after interventions evaluated by Imperial College London and London School of Hygiene and Tropical Medicine aim to reduce incidence in endemic urban centers like Bissau and Dakar and in diaspora communities in cities such as Lisbon and Paris. Vaccine research involving consortia that include NIH Vaccine Research Center, Institut Pasteur, and biotech companies is ongoing although no licensed vaccine has been achieved; public health policy relies on integrated approaches endorsed by World Health Organization and UNAIDS.