Increased mortality and AIDS-like immunopathology in wild chimpanzees infected with SIVcpz.
African primates are naturally infected with over 40 different simian immunodeficiency viruses (SIVs), two of which have crossed the species barrier and generated human immunodeficiency virus types 1 and 2 (HIV-1 and HIV-2). Unlike the human viruses, however, SIVs do not generally cause acquired immunodeficiency syndrome (AIDS) in their natural hosts. Here we show that SIVcpz, the immediate precursor of HIV-1, is pathogenic in free-ranging chimpanzees. By following 94 members of two habituated chimpanzee communities in Gombe National Park, Tanzania, for over 9 years, we found a 10- to 16-fold higher age-corrected death hazard for SIVcpz-infected (n = 17) compared to uninfected (n = 77) chimpanzees. We also found that SIVcpz-infected females were less likely to give birth and had a higher infant mortality rate than uninfected females. Immunohistochemistry and in situ hybridization of post-mortem spleen and lymph node samples from three infected and two uninfected chimpanzees revealed significant CD4(+) T-cell depletion in all infected individuals, with evidence of high viral replication and extensive follicular dendritic cell virus trapping in one of them. One female, who died within 3 years of acquiring SIVcpz, had histopathological findings consistent with end-stage AIDS. These results indicate that SIVcpz, like HIV-1, is associated with progressive CD4(+) T-cell loss, lymphatic tissue destruction and premature death. These findings challenge the prevailing view that all natural SIV infections are non-pathogenic and suggest that SIVcpz has a substantial negative impact on the health, reproduction and lifespan of chimpanzees in the wild.
Keele
Brandon F
BF
Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA.
Jones
James Holland
JH
Terio
Karen A
KA
Estes
Jacob D
JD
Rudicell
Rebecca S
RS
Wilson
Michael L
ML
Li
Yingying
Y
Learn
Gerald H
GH
Beasley
T Mark
TM
Schumacher-Stankey
Joann
J
Wroblewski
Emily
E
Mosser
Anna
A
Raphael
Jane
J
Kamenya
Shadrack
S
Lonsdorf
Elizabeth V
EV
Travis
Dominic A
DA
Mlengeya
Titus
T
Kinsel
Michael J
MJ
Else
James G
JG
Silvestri
Guido
G
Goodall
Jane
J
Sharp
Paul M
PM
Shaw
George M
GM
Pusey
Anne E
AE
Hahn
Beatrice H
BH
D000163:Acquired Immunodeficiency Syndrome / Q000473:pathology; D000349:Africa; D000818:Animals; D000835:Animals, Wild; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D005260:Female; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D002679:Pan troglodytes / Q000821:virology*; D015995:Prevalence; D016097:Simian Acquired Immunodeficiency Syndrome / Q000453:epidemiology / Q000276:immunology / Q000401:mortality* / Q000473:pathology*; D015302:Simian Immunodeficiency Virus / Q000502:physiology*