Am. J. Trop. Med. Hyg., 75(5), 2006, pp. 775
Copyright © 2006 by The American Society of Tropical Medicine and Hygiene
LETTER TO THE EDITOR
LETTERS TO THE EDITOR
Chien-Ching Hung
Hsin-Yun Sun
Shan-Chwen Chang
Division of Infectious Diseases, Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan, Republic of China, E-mail: hcc0401{at}ha.mc.ntu.edu.tw
Dear Sir:
We read with interest the report by Moran and others regarding the relationship between amebiasis and human immunodeficiency virus type 1 (HIV) infection in an area highly endemic for Entamoeba histolytica infection.1 The conclusions of their study may not be supported by their study design and findings. First, the HIV-uninfected control subjects were selected from close relatives or sexual partners of the case patients, which might dilute the correlation between the two infections because they might share the same environment and therefore, the risk of exposure to E. histolytica and E. dispar. Second, whereas there is a trend that the prevalence of E. histolytica carriage in HIV-infected patients is higher than that of the control subjects (25.3% versus 18.4%; P = 0.16), the sample size of the study may limit power to detect a difference between the two groups. Third, the relative risk for E. histolytica infection as determined by a polymerase chain reaction of the stool samples among the homosexuals and bisexuals (prevalence = 38 of 118) compared with HIV-uninfected control subjects (24 of 130, 12 described as active homosexuals) is 1.74 (95% confidence interval = 1.12–2.73). Fourth, the conclusion that E. histolytica strains prevalent in the community appear to be of low pathogenic potential is not supported by the study design and the high seropositivity rate of E. histolytica infection in HIV-infected patients (76 of 145) and control subjects (15 of 35).
The relationship between amebiasis and HIV infection remains controversial, and may be more related to the oral-anal sexual behaviors of homosexuals and bisexuals than to HIV infection. The difference observed in different studies may be due to variability in the epidemiology of HIV infection and E. histolytica infection and study design.2 In an area of lower endemicity such as Japan, where most of cases are found in homosexuals,3 exposure to E. histolytica infection is higher in homosexuals and bisexuals than in heterosexuals and the general population.4,5 To better understand the relationship between HIV infection and E. histolytica infection, more studies with sensitive and specific diagnostic methods6 are needed in areas where both infections are prevalent.
REFERENCES
- Moran P, Ramos F, Ramiro M, Curiel O, Gonzalez E, Valadez A, Gomez A, Garcia G, Melendro EI, Ximenez C, 2005. Infection by human immunodeficiency virus-1 is not a risk factor for amebiasis. Am J Trop Med Hyg 73: 296–300.[Abstract/Free Full Text]
- Hung CC, Deng HI, Hsiao WH, Hsieh SM, Hsiao CF, Chen MY, Chang SC, Su KE, 2005. Invasive amebiasis is an emerging parasitic infection in patients with HIV infection. Arch Intern Med 165: 409–415.[Abstract/Free Full Text]
- Nozaki T, Kobayashi S, Takeuchi T, Haghighi A, 2006. Diversity of clinical isolates of Entamoeba histolytica in Japan. Arch Med Res 37: 277–279.[ISI][Medline]
- Takeuchi T, Okuzawa E, Nozaki T, Kobayashi S, Mizokami M, Minoshima N, Yamamoto M, Isomura S, 1989. High seropositivity of Japanese homosexual men for amebic infection. J Infect Dis 159: 808.[ISI][Medline]
- Tanaka T, Kaneda Y, 1991. Seroepidemiology of anti-Entamoeba histolytica antibody by enzyme-linked immunosorbent assay in the greater Tokyo area. Tokai J Exp Clin Med 16: 253–258.[Medline]
- Tanyuksel M, Petri WA Jr, 2003. Laboratory diagnosis of amebiasis. Clin Microbiol Rev 16: 713–729.[Abstract/Free Full Text]
