EPIDEMIOLOGY

Escherichia coli inhabit the lower small and large intestine of all mammals. Carnivores usually carry larger amounts of this bacterium compared with omnivores and herbiv­ores. The organism is shed with faeces and can survive for weeks and months in faecal particles and dust.

Infectious Diseases of Wild Mammals and Birds in Europe, First Edition. Edited by Dolores Gavier-Widen, J. Paul Duff, and Anna Meredith. © 2012 Blackwell Publishing Ltd. Published 2012 by Blackwell Publishing Ltd.

Wildlife may play a role as carriers and transmitters of Shiga toxin-producing E. coli O157:H7 and non-O157 in nature. High rates (51.8%) of STEC/EHEC- positive faecal samples from clinically normal roe deer ( Capreolus capreo- lus) and red deer (Cervus elaphus) have been found in a German study⁽⁴⁾. In Spain, STEC were detected in 24.7% of red deer, 5% of roe deer, 33.3% of fallow deer (Dama dama), 36.4% of mouflon ( Ovis musimon) and 8.5% of wild boar ( Sus scrofa ) samples investigated^(5,6). Wild brown rats (Rattus norvegicus) tested VTEC-positive in a Danish study⁽⁷⁾. Wild rabbits ( Oryctolagus cuniculus) may also act as vectors for E. coliO157 and non-O157-VTEC⁽⁸⁾. VTEC were also found in wild boar in Sweden⁽⁹⁾, and in gulls (Larus spp.), lapwings (Vanellus vanellus), crows (Corvus corone corone) and jackdaws (Corvus monedula) in the UK⁽¹⁰⁾. A high proportion of feral pigeons ( Columba livia) were found to harbour STEC in Italy⁽¹¹⁾.

In Scotland, E. coli O86:K61 was associated with disease and high mortality in wild birds in household gardens where supplementary food was provided. Chaffinches (Fringilla coelebs), greenfinches ( Carduelis chloris) and Eura­sian siskins (Carduelis spinus) were most frequently affected⁽¹⁴⁾. Escherichia coli O86 was also isolated from an emaciated dead blackbird ( Turdus merula) (Colville, 2010, cited in⁽¹⁵⁾. Isolates from dead finches, previously identified as E. coli O86:K61, were subsequently shown to actually be E. albertii⁽³⁾. This organism was also found to be the prob­able cause of death in several wild birds from USA, Canada and Australia¹-³). In a study in Poland it was found that E. coli O86 could contribute to nestling mortality in wild sparrows (Passer spp.)⁽¹⁶⁾. Escherichia coli 2 (non lactose- fermenting) was found in a blue tit (Parus minor) that died ofcolibacillosis ⁽¹⁵⁾. Pure isolates ofE. coli 1 were grown from liver, spleen and lung of a bittern (Botaurus stellaris) that revealed airsacculitis, pneumonia, pericarditis, hepato- and splenomegaly. Polygranulomatosis (Hjarre’s disease) caused by E. coli O8:H9 and O48:H8 was reported in a free-living common buzzard (Buteo buteo) from Germany⁽¹⁷⁾. VTEC were isolated from several internal organs of a greenfinch in the UK⁽¹⁸⁾. Escherichia coli also accounted for septicaemia in common buzzards, bats⁽¹⁹⁾, hedgehog (Erinaceus euro- paeus)^, European brown hare (Lepus europaeus)^, cirl bunting (Emberiza cirlus) and red kite (Milvus milvus) in the UK (Vaughan 2010, cited in⁽¹⁵⁾. The bacterium was cultured from a pulmonary abscess in a red squirrel (Sciurus vulgaris) in the UK⁽¹⁵⁾ and was associated with enteritis in roe deer in the UK⁽¹⁸⁾.