text: Here is a review on the epidemiology\nhttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=16554248&query_hl=5&itool=pubmed_DocSum\n\nHere is a review of the pathogenesis\n\nhttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=16182593&query_hl=5&itool=pubmed_DocSum\n\nAlso here is some studies on the evolution of transmission\n\nhttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=16053250&query_hl=5&itool=pubmed_DocSum