Diagnosis is usually made by serology. A high antibody titer can be detected by enzyme-linked immunosorbent assay (ELISA), but is not very sensitive in the first week [49] . Titers become positive during the second week of infection in 50 to 70% of cases, and reach their highest level after 4 to 8 weeks [50] . Definitive diagnosis can also be made by culture of oropharyngeal specimens or fasting gastric fluid; however, the organism rarely can be isolated from blood [48] . PCR from wound swabs is 78% sensitive and 96% specific [51] .