Possible brucellosis in an early hominin skeleton from sterkfontein, South Africa

Abstract

We report on the paleopathological analysis of the partial skeleton of the late Pliocene hominin species Australopithecus africanus Stw 431 from Sterkfontein, South Africa. A previous study noted the presence of lesions on vertebral bodies diagnosed as spondylosis deformans due to trauma. Instead, we suggest that these lesions are pathological changes due to the initial phases of an infectious disease, brucellosis. The macroscopic, microscopic and radiological appearance of the lytic lesions of the lumbar vertebrae is consistent with brucellosis. The hypothesis of brucellosis (most often associated with the consumption of animal proteins) in a 2.4 to 2.8 million year old hominid has a host of important implications for human evolution. The consumption of meat has been regarded an important factor in supporting, directing or altering human evolution. Perhaps the earliest (up to 2.5 million years ago) paleontological evidence for meat eating consists of cut marks on animal remains and stone tools that could have made these marks. Now with the hypothesis of brucellosis in A. africanus, we may have evidence of occasional meat eating directly linked to a fossil hominin.

Figure 1. Lumbar vertebrae L5 and L4 of Australopithecus africanus Stw 431.

Stereomicroscopic and radiographic studies of L5 (A, B), and L4 (C, D). Scanning Electron Microscope (SEM) analysis showing Howship's lacunae of L5 (E) and L4 (F).

Figure 2. The lytic lesions on Stw's 431 L4 and L5 were compared with ancient modern human lumbar vertebrae affected by brucellosis and tuberculosis, and with Scheuermann's disease in a living young male.

Modern human L4 affected by tuberculosis: macroscopic (A) and radiographic picture (B) (Courtesy of Capasso; adult female E58, Herculaneum, 79 AD, University Museum of Chieti). Scheuermann's disease in the vertebral column of a living 18 years old male: Radiographic analysis (C) (Courtesy of Zipfel; School of Anatomical Sciences at the University of the Witwatersrand). Modern human L4 affected by brucellosis: macroscopic (D) and radiographic picture (E) (Courtesy of Capasso; adult female E50, Herculaneum, 79 AD, University Museum of Chieti).