In conclusion, we have demonstrated SARS-CoVtropism towards lung pneumocytes and intestinal surfaceenterocytes in fatal cases of SARS. The resultscontribute to our understanding of the pathology ofthis new human infectious disease. The distinct tissuesand cellular tropism highlight the novel biologyof SARS-CoV, which may require a distinct set ofreceptor proteins for its tropism. Further studies ofthese receptors may have an important impact on thedevelopment of drugs for the treatment of this newhuman disease.