HIV-associated cognitive impairment in sub-Saharan Africa—the potential effect of clade diversity

Abstract

In the US, HIV dementia occurs in 10–15% of HIV-positive individuals with advanced infection. The prevalence of HIV dementia in sub-Saharan countries, where the vast majority of individuals with HIV reside, is largely unknown. This Review will summarize our current understanding of HIV-associated cognitive impairment in resource-limited settings, focusing specifically on the countries of sub-Saharan Africa. We will describe the frequency of HIV dementia and HIV-associated cognitive impairment from several case series in the sub-Saharan region. We will then summarize recent studies from Uganda and Ethiopia that included detailed neuropsychological assessments. The potential influence of clade diversity on HIV-associated cognitive impairment will be discussed. Differences between the results of the studies in Uganda and in Ethiopia raise the possibility that HIV subtypes might have different biological properties with respect to their capacity to cause HIV-associated cognitive impairment. Further studies are needed to determine the true prevalence of HIV dementia in sub-Saharan Africa and to establish whether specific clade subtypes might influence the presentation of neurological complications.

Key Points

  • HIV dementia is characterized by cognitive, behavioral and motor dysfunction

  • HIV-1 subtypes in the US and Europe differ from subtypes seen elsewhere in the world

  • The frequency of HIV dementia in sub-Saharan Africa is largely unknown, but one study in Uganda suggests that 31% of HIV-positive individuals with advanced infection could have dementia

  • Differences in HIV-1 subtype could cause differences in HIV-associated neurological disease

  • HIV dementia might be among the most common forms of dementia worldwide, along with Alzheimer's disease and vascular dementia

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

Figure 1: Global distribution of HIV-1 viral subtypes

References

  1. 1

    Joint United Nations Program on HIV/AIDS.UN/AIDS and The World Health Organization. AIDS Epidemic Update, Dec 2003

  2. 2

    Sacktor N (2002) The epidemiology of human immunodeficiency virus-associated neurological disease in the era of highly active antiretroviral therapy. J Neurovirol 8 (Suppl 2): S115–S121

    Article  Google Scholar 

  3. 3

    Birbeck GL (2005) Human immunodeficiency virus dementia patients in Africa: How many? Who cares? And where to from here? J Neurovirol 11 (Suppl 3): S30–S33

    Article  Google Scholar 

  4. 4

    Sacktor NC et al. (2005) The International HIV Dementia Scale: a new rapid screening test for HIV dementia. AIDS 19: 1367–1374

    PubMed  Google Scholar 

  5. 5

    Spira S et al. (2003) Impact of clade diversity on HIV-1 virulence, antiretroviral drug sensitivity and drug resistance. J Antimicrob Chemother 51: 229–240

    CAS  Article  Google Scholar 

  6. 6

    Simon F et al. (1998) Identification of a new human immunodeficiency virus type 1 distinct from group M and group O. Nat Med 4: 1032–1037

    CAS  Article  Google Scholar 

  7. 7

    Renjifo B and Essex M (2002) HIV-1 subtypes and recombinants. In AIDS in Africa, 138–157 (Eds Essex M et al.) New York: Kluwer Academic/Plenum Publishers

    Google Scholar 

  8. 8

    Quinones-Mateu ME and Arts EJ (1999) Recombination in HIV-1: update and implications. AIDS Rev 1: 89–100

    Google Scholar 

  9. 9

    Triques K et al. (2000) Near-full-length genome sequencing of divergent African HIV type 1 subtype F viruses leads to the identification of a new HIV type 1 subtype designated K. AIDS Res Hum Retroviruses 16: 139–151

    CAS  Article  Google Scholar 

  10. 10

    Piot P and Bartos M (2002) The epidemiology of HIV and AIDS. In AIDS in Africa, 200–217 (Eds Essex M et al.) New York: Kluwer Academic/Plenum Publishers

    Google Scholar 

  11. 11

    Janssens W et al. (1997) The puzzle of HIV-1 subtypes in Africa. AIDS 11: 705–712

    CAS  Article  Google Scholar 

  12. 12

    Coffin JM et al. 1997) Retroviruses. New Jersey: Cold Spring Laboratory Press

    Google Scholar 

  13. 13

    Sacktor N et al. (2006) Antiretroviral therapy improves cognitive impairment in HIV+ individuals in sub-Saharan Africa. Neurology 67: 311–314

    CAS  Article  Google Scholar 

  14. 14

    Laeyendecker O et al. (2006) The effect of HIV subtype on rapid disease progression in Rakai, Uganda [abstract #44LB]. Presented at the 13th Conference on Retroviruses and Opportunistic Infections: 2006 February 5–8, Denver, CO

  15. 15

    Vasan A et al. (2006) Different rates of disease progression of HIV type 1 infection in Tanzania based on infecting subtype. Clin Infect Dis 42: 843–852

    Article  Google Scholar 

  16. 16

    Maj M et al. (1994) WHO Neuropsychiatric AIDS study, cross-sectional phase II: neuropsychological and neurological findings. Arch Gen Psychiatry 51: 51–61

    CAS  Article  Google Scholar 

  17. 17

    Howlett WP et al. (1989) Neurological disorders in AIDS and HIV disease in the northern zone of Tanzania. AIDS 3: 289–296

    CAS  Article  Google Scholar 

  18. 18

    Perriens JH et al. (1992) Neurological complications of HIV-1-seropositive internal medicine inpatients in Kinshasa, Zaire. J Acquir Immune Defic Syndr 5: 333–340

    CAS  PubMed  Google Scholar 

  19. 19

    Pierotti C et al. (2002) A prospective study on neuro-AIDS with emphasis on cerebrospinal fluid analysis in an Ugandan rural hospital. J Neurovirol 8 (Suppl): SP224

    Google Scholar 

  20. 20

    Wong M et al. (2007) Frequency of and risk factors for HIV dementia in an HIV clinic in sub-Saharan Africa. Neurology 68: 350–355

    CAS  Article  Google Scholar 

  21. 21

    Wechsler D (1981) Wechsler Adult Intelligence Scale Revised. New York: The Psychological Corporation

    Google Scholar 

  22. 22

    Selnes OA et al. (1991) Normative data for a brief neuropsychological screening battery. Percept Mot Skills 73: 539–550

    CAS  Article  Google Scholar 

  23. 23

    Lawton MP and Brody EM (1969) Assessment of older people: self-maintaining and instrumental activities of daily living. Gerontologist 9: 179–186

    CAS  Article  Google Scholar 

  24. 24

    Katz S et al. (1963) Studies of illness in the aged: the index of ADL. JAMA 183: 914–919

    Article  Google Scholar 

  25. 25

    Karnofsky DA et al. (1948) The use of nitrogen mustards in the palliative treatment of carcinoma. Cancer 1: 634–656

    Article  Google Scholar 

  26. 26

    Clifford D et al. (2007) Neurological evaluation of untreated human immunodeficiency virus infected adults in Ethiopia. J Neurovirol 13: 67–72

    Article  Google Scholar 

  27. 27

    Clifford DB et al. (2005) Impact of efavirenz on neuropsychological performance and symptoms in HIV-infected individuals. Ann Intern Med 143: 714–721

    CAS  Article  Google Scholar 

  28. 28

    Schmitt FA et al. (1988) Neuropsychological outcome of zidovudine (AZT) treatment of patients with AIDS and AIDS-related complex. N Engl J Med 319: 1573–1578

    CAS  Article  Google Scholar 

  29. 29

    Ball SC et al. (2003) Comparing the ex vivo fitness of CCR5-tropic human immunodeficiency virus type 1 isolates of subtypes B and C. J Virol 77: 1021–1038

    CAS  Article  Google Scholar 

Download references

Acknowledgements

The authors thank Alice Namudde and Fred Sebuuma for their work as research assistants for the Ugandan studies, and Marie Sonderman for providing administrative support.

Author information

Affiliations

Authors

Corresponding author

Correspondence to Ned Sacktor.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Sacktor, N., Nakasujja, N., Robertson, K. et al. HIV-associated cognitive impairment in sub-Saharan Africa—the potential effect of clade diversity. Nat Rev Neurol 3, 436–443 (2007). https://doi.org/10.1038/ncpneuro0559

Download citation

Further reading