**7.2 Prevalence in association with other disorders**

In people with AIDS, leukemia and lynmphoma, the prevalence of symptomatic infectious esophagitis is high, but it is less than 5% in the general population, which is low.

As noted stated previously, the most common type of infectious esophagitis is Candida esophagitis. The second most common infectious esophagitis is HSV esophagitis, which has been reported in about 1% of immunosuppressed patients, and in as many as 43% of the patients in autopsy investigations [23–28].

Another etiological agent for esophagitis is CMV. A big percentage of the global population has been exposed to CMV and asymptomatic CMV infection is common around the world [29, 30].

CMV esophagitis was usually discovered on post-mortem analysis prior to the AIDS epidemic, and the first clinical case of CMV esophagitis was reported in 1985 [30].

CMV does not occur in immunocompetent people unlike HSV esophagitis, and the majority of the people with CMV esophagitis have AIDS [29, 30]. Since the

advent of highly active antiretroviral therapy, the incidence of CMV esophagitis like those of other types of infectious esophagitis has declined among people with AIDS [29, 30]. On the other hand, there has been reported increase of CMV esophagitis in people who had undergone solid organ transplant, and in whom the onset of the disease was delayed due to the increasing routine of early CMV prophylaxis [31].

In AIDS patients in whom no other infectious etiological factors can be identified [32–36], giant esophageal ulcers have been observed [37], which have been called idiopathic HIV ulcers because they are believed to be caused by HIV, as electron microscopic investigation had confirmed the presence of HIV-like viral particles in the ulcer lesions [32–37].

Most patients have been found to have chronic AIDS with CD4 counts less than 100 cells/uL, despite the fact that some patients with HIV ulcers may have undergone recent seroconversion [38–41]. Ulcers associated with HIV have been under recognized generally, as it accounts for about 40% of all reported esophageal ulcers in AIDS patients [32–42].
