Skip to main content

Chimpanzee deaths at Mahale caused by a flu-like disease


A flu-like disease spread among chimpanzees (Pan troglodytes schweinfurthii) of the M group at Mahale Mountains National Park, Tanzania, from June to July 2006. This epizootic or epidemic killed up to 12 chimpanzees. The obvious evidence of their deaths came from finding the bodies of three infants who had previously shown some symptoms of the disease. At least one of these infants died of pneumonia. In addition, nine chimpanzees were missing after the outbreak. These individuals were assumed to have been killed by this epizootic because most of them had contact with the infected individuals on the last days they were observed. We also found two dead bodies during this period, which were thought to be those of two missing individuals. We confirmed 23 (35.4%) of 65 individuals of the M group showed some symptoms of the disease, although most of them (20/23) did not die. More than half of them (14/23) had kin showing symptoms. Since this epizootic may have been caused by contact with humans, it will be necessary to establish and follow appropriate protocols for researchers, tourists, and park staff to observe chimpanzees, and to explore the mechanism of disease transmission from humans to chimpanzees and among chimpanzees.

This is a preview of subscription content, access via your institution.

Fig. 1


  • Boesch C, Boesch-Achermann H (2000) The chimpanzees of the Taï forest: behavioural ecology and evolution. Oxford University Press, Oxford

    Google Scholar 

  • Goodall J (1986) The chimpanzees of Gombe: patterns of behavior. Harvard University Press, Cambridge

    Google Scholar 

  • Hanamura S, Kiyono M, Nakamura M, Sakamaki T, Itoh N, Zamma K, Kitopeni R, Matumla M, Nishida T (2006) A new code of observation employed at Mahale: prevention against a flu-like disease. Pan Afr News 13:13–16

    Google Scholar 

  • Hosaka K (1995) A single flu epidemic killed at least 11 chimps. Pan Afr News 2(2):3–4

    Google Scholar 

  • Itoh N, Nishida T (2007) Chimpanzee grouping patterns and food availability in Mahale Mountains National Park, Tanzania. Primates 48:87–96

    Article  PubMed  Google Scholar 

  • Lonsdorf EV, Travis D, Pusey AE, Goodall J (2006) Using retrospective health data from the Gombe chimpanzee study to inform future monitoring efforts. Am J Primatol 68:897–908

    Article  PubMed  CAS  Google Scholar 

  • Matsuzawa T, Humle T, Koops K, Biro D, Hayashi M, Sousa C, Mizuno Y, Kato A, Yamakoshi G, Ohashi G, Sugiyama Y, Kourouma M (2004) Wild chimpanzees at Bossou-Nimba: deaths through a flu-like epidemic in 2003 and the Green-Corridor Project. Primate Res 20:45–55

    Article  Google Scholar 

  • Nishida T (ed) (1990) The chimpanzees of the Mahale Mountains. University of Tokyo Press, Tokyo

  • Nishida T, Corp N, Hamai M, Hasegawa T, Hiraiwa-Hasegawa M, Hosaka K, Hunt KD, Itoh N, Kawanaka K, Matsumoto-Oda A, Mitani JC, Nakamura M, Norikoshi K, Sakamaki T, Turner L, Uehara S, Zamma K (2003) Demography, female life history, and reproductive profiles among the chimpanzees of Mahale. Am J Primatol 59:99–121

    Article  PubMed  Google Scholar 

  • Reynolds V (2005) The chimpanzees of the Budongo forest: ecology, behaviour, and conservation. Oxford University Press, Oxford

    Google Scholar 

  • Wallis J, Lee DR (1999) Primate conservation: the prevention of disease transmission. Int J Primatol 20:803–826

    Article  Google Scholar 

  • Woodford MH, Butynski TM, Karesh WB (2002) Habituating the great apes: the disease risks. Oryx 36:153–160

    Article  Google Scholar 

Download references


We thank COSTECH, TAWIRI, TANAPA and Mahale Mountains National Park for permission to conduct research; R. Kitopeni and M. Matumula for assisting in the research; A. H. Harcourt and K. N. Cameron for useful comments; and H. Y. Kayumbo, T. Nemoto, and A. Inaba for encouragement. This study was financed by MEXT Grants-in-Aid for Scientific Research (#16255007 to TN and #16770186 to MN) and a Global Environment Research Fund (F-061 to TN) from the Ministry of Environment.

Author information

Authors and Affiliations


Corresponding author

Correspondence to Shunkichi Hanamura.

About this article

Cite this article

Hanamura, S., Kiyono, M., Lukasik-Braum, M. et al. Chimpanzee deaths at Mahale caused by a flu-like disease. Primates 49, 77–80 (2008).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: