HIV-2/LAV-2 in Portuguese man with AIDS (Paris, 1978) who had served in Angola in 1968-74

[HIV genetic diversity and its consequences]

Human immunodeficiency viruses HIV-1 and HIV-2 are the results of multi-interspecies transmissions from simian virus to humans. HIV-1 viruses are very divergent and are classified in three groups: M, N and O. The group M is subdivided in nine subtypes and numerous Circulating Recombinant Forms. In 1996, protease inhibitors and HAART disposal have modified the prognostic of the HIV infection. However, one of the major problems is the emergence of antiretroviral resistance. A major advance from the last year is the access to antiretroviral in resources limited countries. On the other hand, the development of a vaccine is today hypothetic.

HIV type 2 demyelinating encephalomyelitis

A human immunodeficiency virus (HIV) type 2 (HIV-2)-infected African patient developed inflammatory demyelinating lesions of the optic nerves, spinal cord, and brain, which coincided with a decreasing CD4 cell count and with active HIV-2 replication. This case provides evidence that HIV-2 is neurotropic, extends the range of known HIV-2-associated neurological complications, and confirms the overlap between the neurological complications of HIV type 1 and HIV-2 infection.

Longstanding presence of HIV-2 infection in Guinea-Bissau (West Africa)

We have retrospectively studied the seroprevalence of the human immunodeficiency virus (HIV) in Guinea-Bissau in a sample of sera collected from the whole country in 1980. We tested a total of 1248 individuals and found 11 individuals who were seropositive for HIV-2 but there were no HIV-1 seropositive samples. The mean age of the HIV-2 seropositive people was significantly higher than the age of the seronegative individuals. In the different areas surveyed, the HIV-2 seroprevalence ranged from 0 to 2.5%. A central region of the country, grossly centred in the capital city of Bissau, presented the highest prevalence of HIV-2 seropositivity (>2%), which contrasts with its virtual absence from the more remote rural areas located near the borders with the neighbouring countries. The overall seroprevalence found for HIV-2 in this study is 0.9% (1.8%, when considering the adult seroprevalence only), which proves that the virus was definitely circulating in Guinea-Bissau at the beginning of the 1980s.

Epidemiological characteristics of human immunodeficiency virus type-2 infection in Africa

There are things yet to be clarified about African HIV-2 infection, compared to HIV-1 infection. However, the epidemiological characteristics have gradually been elucidated through various studies. HIV-2 infection is believed to have existed in the 1960s in Africa and is presently epidemic in West Africa. The HIV-2 seropositive rate for the general population is higher in urban regions than in rural areas. The peak age of persons infected with the HIV-2 tends to be higher than that of persons infected with the HIV-1, but no sex difference was recognized between the HIV-2 and HIV-1 seropositive rates. Sexual contact, mother-to-child transmission and blood transfusion have been confirmed as HIV-2 transmission modes. Prostitutes and patients with other STD are recognized as being high-risk groups for the HIV-2 infection. Patients who are infected with both HIV-1 and HIV-2 have also been identified, but it is suggested that the pathogenicity of HIV-2 is lower than that of HIV-1.

Diagnosis of human immunodeficiency virus (HIV) infection: multicenter evaluation of a newly developed anti-HIV 1 and 2 enzyme immunoassay

A new anti-human immunodeficiency virus type 1 and 2 (anti-HIV 1 and 2) test is described. It uses recombinant p24 and peptides covering gp32, gp41, and gp120 to identify HIV-1 and HIV-2 infections. This test has been shown to be specific (99.5%) and sensitive (99.8%). In this respect, the assay was equal or superior to anti-HIV 1 and 2 tests run as references. The test was able to discriminate sera from patients with HIV infections from those from uninfected individuals with excellence; it also exerted high intra- and interassay precisions. The "modular" concept of the test allows the use of single components (gp32 or gp41) to separate between HIV-2 and HIV-1 infections, respectively.

Identification of infection of an Australian resident with the human immunodeficiency virus type 2 (HIV-2)

OBJECTIVE

To present the first confirmed case of human immunodeficiency virus infection type 2 (HIV-2) in an Australian resident.

CLINICAL FEATURES

HIV-2 infection in a west African man resident in Sydney was diagnosed in 1992 at Westmead Hospital, Sydney, by serological testing. He was asymptomatic and the blood CD4 T-lymphocyte concentration was not significantly reduced. Infection was probably acquired before migration to Australia. The patient was initially tested for HIV-1 antibody as part of an application for permanent residency. He was in no obvious risk group or transmission category. His serum was repeatedly positive by Genetic Systems enzyme immunoassay (EIA) and borderline by Abbott EIA, was reactive to the HIV-2 peptide on a synthetic envelope peptide assay, and was strongly reactive to all HIV-2 specific viral protein bands on an HIV-2 western blot test. HIV-2 was isolated by co-cultivation of the patient's peripheral blood mononuclear cells and identified by hybridisation using HIV-2 specific oligonucleotide probes, with further confirmation by polymerase chain reaction.

INTERVENTION AND OUTCOME

The patient was counselled regarding the clinical course and prognosis of HIV-2 infection, the possible indications for zidovudine therapy, modes of transmission of the virus and safer sex precautions.

CONCLUSIONS

This is the first documented case of HIV-2 infection diagnosed in Australia and raises the possibility of other undetected cases. The cost effectiveness of general testing for HIV-2 needs to be assessed and formal epidemiological sentinel programs should be established to monitor specific Australian populations.

Evaluation of a line immunoassay for simultaneous confirmation of antibodies to HIV-1 and HIV-2

An anti-HIV-1/HIV-2 line immunoassay (LIA), using peptides and recombinant antigens was evaluated against commercially available Western blot tests for HIV-1 and HIV-2 antibodies. Two thousand one hundred and ten sera of European, African, and South American origin were used in the evaluation. The panel included 1066 sera with antibodies to HIV-1, 192 sera with antibodies to HIV-2, and 64 sera with antibodies to both. Using Western blot results interpreted according to the WHO criteria as a reference standard, the overall specificity obtained by this LIA was 100% and the sensitivity was 99.77% (97.51-100% for 95% confidence limits) when sera dually reactive in Western blot were included. Of the three sera negative in the LIA but positive in HIV-1 WB, two could be retested in a radioimmunoprecipitation assay and were negative. When dually reactive sera in the Western blot (WHO) were included, the LIA yielded 9.9% indeterminate results as compared with 15.5% for both assays (chi 2 = 29.30; p less than 0.001). Although only one HIV-2 specific peptide antigen (gp36) was used, the LIA yielded a specificity of 100% and a sensitivity of 100% as compared with the HIV-2 Western blot assay. When indeterminate results were included, the overall agreement between the LIA and the HIV-1 and HIV-2 Western blot (WHO criteria) was 89.9% and 90.1% respectively. These results indicate that the LIA provides reliable simultaneous detection of antibodies to HIV-1 and HIV-2, and at a cost which is substantially lower than the cost of Western blot tests.

A comparison of four enzyme immunoassays for the simultaneous detection of HIV-1- and HIV-2-specific antibody

The performance of four HIV 1 and 2 combined assays has been compared with current type-specific assays using three panels of sera. The first panel comprised single samples from 19 HIV-1-infected persons; the second panel comprised 19 sera from 16 HIV-2-infected persons. Samples from both these panels were titrated across interpolated end points of detectability. The third panel comprised sera from 5200 consecutive blood donors. The four combined assays, manufactured by Abbott Laboratories, Behring Laboratories, Diagnostics Pasteur and Wellcome Diagnostics Laboratories detected all anti-HIV-1 sera at high dilution; the immunometric assay from Wellcome was particularly proficient. All assays were broadly similar in their ability to detect sera from recently infected persons. The same assays were also effective in detecting anti-HIV 2 in sera both from seropositive individuals and from a single recently-infected person, though none was as sensitive as an inhouse competitive EIA. When used for donor screening the repeat reactive rates for donors negative for HIV 1 and 2 antibodies ranged between 1.80% for Elavia Mixt from Pasteur, 0.27% Abbott combined and 0.15% for the Wellcome combined assays.

Civil war and the spread of AIDS in Central Africa

Using ordinary least squares regression techniques this paper demonstrates, for the first time, that the classic association of war and disease substantially accounts for the presently observed geographical distribution of reported clinical AIDS cases in Uganda. Both the spread of HIV 1 infection in the 1980s, and the subsequent development of AIDS to its 1990 spatial pattern, are shown to be significantly and positively correlated with ethnic patterns of recruitment into the Ugandan National Liberation Army (UNLA) after the overthrow of Idi Amin some 10 years earlier in 1979. This correlation reflects the estimated mean incubation period of 8-10 years for HIV 1 and underlines the need for cognizance of historical factors which may have influenced current patterns of AIDS seen in Central Africa. The findings may have important implications for AIDS forecasting and control in African countries which have recently experienced war. The results are compared with parallel analyses of other HIV hypotheses advanced to account for the reported geographical distribution of AIDS in Uganda.

Human immunodeficiency virus type 2 (HIV2)

In the mid 1980's a second human retrovirus, capable of causing the acquired immunodeficiency syndrome (AIDS), was isolated from patients of West African origin. This virus, now called human immunodeficiency virus type 2 (HIV2), was found to be distinct from human immunodeficiency virus type 1 (HIV1) but closely related to simian immunodeficiency viruses (SIV). Although the genomes of HIV1 and HIV2 are similar there are significant differences in nucleotide and amino acid sequences, most marked with the envelope genes and proteins. Both viruses, however, bind to the same CD4 cellular receptor. HIV2 is largely confined to West Africa where it is the dominant HIV, though patients infected with HIV2 have been described in Europe and America. Its transmission, clinical features and immunological effects are similar to those associated with HIV1 infection. However, there is some suggestion that the incubation period from infection to clinical disease may be longer than with HIV1 and that HIV2 may be less pathogenic. Patients with sera that react with both HIV1 and HIV2 antigens have been described, but it is unclear whether this represents serological cross reactivity or true double virus infection. Testing for HIV2 antibodies may become increasingly necessary in HIV2 non-endemic areas.

Diagnosis and prevalence of HIV-2 antibodies in different population subsets in The Netherlands

A serum panel obtained from male homosexuals (n = 278); i.v. drug abusers (n = 99), patients attending a VD clinic (n = 390), blood donors who visited Central or West Africa (n = 573), blood donors who had sexual contact with natives from Central or West Africa (n = 38), blood donors from Surinam, South America (n = 481), individuals positive for anti-HIV-1 (n = 94), individuals with indeterminate HIV-1 western blot (WB) reactions (n = 73), African patients with AIDS or AIDS-related symptoms (n = 30), and random Dutch blood donors (n = 555), was tested with HIV-2 ELISA (ELAVIA-2). Of these 2,611 samples, 32 (1.2%) were repeatedly reactive. Antibodies to gp140/105env were found in 4/32 by HIV-2 WB, and in 1/4 by radioimmunoprecipitation (RIPA). These 4 HIV-2 WB-positive samples were also reactive with gp160/120env in HIV-1 WB, suggesting cross-reactivity. In a spot test with synthetic peptides of the transmembrane glycoprotein of both HIV types, 3/4 were only HIV-1 positive and 1/4 was strongly HIV-2 positive and weakly HIV-1 positive. In inhibition assays with soluble HIV-1 or HIV-2 synthetic peptides in HIV-1 and HIV-2 peptide ELISA, cross-reactivity was excluded, which indicates an HIV variant or HIV-1/HIV-2 double infection. It is concluded that for the moment HIV-2 infection is at low prevalence in risk groups in The Netherlands, and that in addition to WB and RIPA, synthetic peptide assays are useful for differentiation between HIV-1 and HIV-2 antibodies.

Comparison of 10 enzyme immunoassays for detection of antibody to human immunodeficiency virus type 2 in West African sera

The efficacies of nine enzyme-linked immunosorbent assays (EIA) for antibody to human immunodeficiency virus type 1 (HIV-1) and one EIA for antibody to HIV-2 in detecting antibody to HIV-2 were studied. The competitive EIAs for antibody to HIV-1 were less sensitive than the indirect EIAs. The overall prevalence of positive results was between 28 and 51% with the competitive EIAs and between 70 and 93% with the indirect EIAs. Most of the EIAs were less sensitive in detecting antibody to HIV-2 in sera from people with acquired immunodeficiency syndrome-like diseases than in sera from symptomless individuals. The results indicate that there is a high degree of cross-reactivity between HIV-1 and HIV-2 by EIA, indicating that serotype specificity must be determined by Western blot (immunoblot) with both sets of viral antigens. The results are relevant for discussing public health strategies, especially the screening of blood donors; competitive EIAs for antibody to HIV-1 are not sensitive enough to be used in areas where HIV-2 is prevalent (West Africa).

HIV-II infection with initial neurological manifestation

A patient with positive serological HIV-II reactions is presented, who lived for many years in North and West Africa and on the Arabian peninsula, and who developed asthenica, incontinence, gait disturbances, impaired mental function, personality changes and finally spastic paraplegia and peripheral neuropathy. He was shown to have a chronic inflammatory process of the central nervous system with cerebral atrophy.

The global distribution of human immunodeficiency virus type 2 (HIV-2) infection

We reviewed published reports of infection with human immunodeficiency virus type 2 (HIV-2) to provide a picture of its geographic distribution, pathogenicity, modes of transmission, and risk to the blood supply. Since the first reports in 1986, 627 HIV-2-seropositive persons have been reported; 604 of these were in natives of West Africa. Acquired immunodeficiency syndrome (AIDS) had developed in 42 patients, while 8 patients had AIDS-related complex. Transmission by sexual intercourse was the usual reported mode of spread. The modes of transmission of HIV-2 are thought to be the same as those for HIV-1, but perinatal transmission and transmission by sharing of needles among intravenous drug abusers have not yet been reported. The virus has not been identified in blood donors in the United States or West Germany, but two HIV-2-infected blood donors were reported in France. Further epidemiologic studies are needed to define the spectrum of disease, modes of transmission, and risk of HIV-2 to the blood supply.