Possible Brucellosis in an Early Hominin Skeleton from Sterkfontein, South Africa

30th July 2009

In this paper by Ruggero D’Anastasi and his colleagues, they show how lesions in the fossilised lumbar vertebrae of Australopithecus africanus Stw 431 from Sterkfontein, South Africa may have been caused by the individual’s consumption of meat during its lifetime, prompting the researchers to ask to what extent australopithecines living between 2.4 million and 2.8 million years BP may have included meat in their diet.

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.

As is noted in the freely accessible paper, brucellosis is sometimes associated in modern populations with the consumption of of dairy products and unpasteurised cheese, but can also be passed on through infected meat. The lesions in the vertebrae ostensibly also conform to spondylosis caused by traumatic injury, but upon close examination we see:

A preliminary examination revealed the presence of some pathological lesions on the vertebral bodies. Lumbar vertebrae L4 and L5 have lytic lesions on the superior-anterior margin of the vertebral bodies; in particular L5 showed an excavation of the anterior-superior body with osteophytes. The position and gross morphology of the lesions were very similar to the pathological bone alterations observed in some infectious diseases in modern humans, such as in human zoonotic brucellosis [15].

The researchers postulate that this may be the oldest yet known, albeit indirect evidence that A. africanus may have included meat in their diet, and because carnivorous activity has also been observed in baboons and chimpanzees, it doesn’t seem unreasonable to suggest that predecessors of Homo may also have eaten meat. Meat consumption is suggested to have have played a significant role in human evolution, but it has yet to be confirmed when our ancestors began eating meat in sufficient quantities for evolution to have been affected, or indeed exactly the effects would have been.

Reference: D’Anastasio R, Zipfel B, Moggi-Cecchi J, Stanyon R, Capasso L (2009) Possible Brucellosis in an Early Hominin Skeleton from Sterkfontein, South Africa. PLoS ONE 4(7): e6439. doi:10.1371/journal.pone.0006439

Fuente: Anthropology