tap water may be an important source of Cryptosporidium spp for AIDS patients, and that debilitating disease might be avoided by a simple measure which removes viable oocysts, such as boiling tap water.7 We thank Dr R. T. Mayon-White, Oxfordshire department of public health, and Dr J. S. Colbourne, water and environmental sciences, Thames Water Utilities, Reading, for their criticisms and provision of data on water samples. Renal Transplant Unit, Churchill Hospital, Oxford
C. P. CLIFFORD
Public Health Laboratory, John Radcliffe Hospital, Oxford OX3 9DU, UK
D. W. M. CROOK
Department of Infectious Diseases, John Radcliffe Hospital
C. P. CONLON
Public Health Laboratory, John Radcliffe Hospital
Department of Infectious Diseases, John Radcliffe Hospital
A. P. FRAISE
D. G. DAY T. E. A. PETO
Fayer R, Ungar BLP. Cryptosporidium spp and cryptosporidiosis. Microbiol Rev 1986;
50: 458-83. 2. Current WL, Reese NC, Ernst JV, et al. Human cryptosporidiosis m immunocompetent and immunodeficient persons: studies of an outbreak and experimental transmission. N Engl J Med 1983; 308: 1252-57. 3. Rene E, Marche C, Regnier B, et al. Intestinal infections in patients with acquired immunodeficiency syndrome: a prospective study in 132 patients. Dig Dis Sci 1989; 34: 773-80. 4. Hayes EB, Matte TD, O’Brien TR, et al. Large community outbreak of cryptosporidiosis due to contamination of a filtered public water supply. N Engl J Med 1989; 320: 1372-75. 5. Dick TA. Report of an enquiry into water supplies in Oxford and Swindon following an outbreak of cryptosporidiosis during February-March 1989. Reading: Thames Water Utilities, 1989. 6. Editorial. HIV-associated enteropathy. Lancet 1989; ii: 777-78. 7. Casemore DP, Blewett DA, Wright SE. Cleaning and disinfection of equipment for gastrointestinal flexible endoscopy: interim recommendations of a working party of the British Society of Gastroenterology. Gut 1989; 30: 1156-57.
Helicobacter pylori and HIV infection SIR,7-Helicobacter pylori infection is the main cause of nonautoimmune gastritis’ and it may be a major factor in duodenal ulceration.2 Antibodies to H pylori are found in up to 21% of healthy blood donors in the UK,3and recent studies in the general population suggest an age-related seroprevalence ranging from 30% in those aged 30-35 to more than 60% in those over 45 (D. Forman, personal communication). A retrospective study of HIV seropositive patients undergoing upper gastrointestinal endoscopy revealed H pylori in antral biopsies in only 15 % of cases compared with 47% of age, sex, and symptom matched HIVnegative controls.4 However, retrospective studies by other groups have produced conflicting results.S.6 We have done a prospective study of the prevalence of Hpylori in HIV-positive patients referred for endoscopy. All HIV-positive patients referred for endoscopy between Sept 1, 1988, and Aug 31,1989, completed a questionnaire on symptoms, cigarette and alcohol consumption, current or recent medication, and previous complications of HIV infection. At endoscopy three antral specimens were taken, two for histology and one to detect H pylori (’CLO-test’, Delta West Laboratories, Australia). Histological changes were assessed by M. M. W. on sections stained with haematoxylin and eosin and by the Gimenez technique.7 H pylori antibodies were sought by an ELISA based on the acid glycine extract antigen (University Diagnostics, University College, London). Because many patients were being treated with zidovudine, acyclovir, and ketoconazole or fluconazole, in-vitro activities against H pylori were also assessed. 79 endoscopies were done on 61 patients, 38 with AIDS. Their median age was 38 (range 25-58). The usual indications for endoscopy were abdominal pain, nausea, dysphagia, and/or dyspepsia. Hpylori was found in 11 (18%) patients, 6 with AIDS. Of the 15 HIV-positive patients with dyspepsia only 2 had evidence of H pylori infection compared with 18 (60%) of 30 age, sex, and
symptom matched HIV-negative controls (p < 0.01). Histological evidence of gastritis was found in 11 HIV-positive patients and 16 with AIDS, with H pylori present in 5 and 6, respectively. Zidovudine, acyclovir, and ketoconazole or fluconazole were being taken by 53%, 26%, and 23%, respectively, of the
HIV-positive patients but none of these drugs had any activity against H pylori in vitro, alone or in combination. No patient had taken bismuth compounds or antibiotics known to be effective against H pylori in the 2 months before endoscopy. These findings confirm the low prevalence of H pylori infection in HIV-positive patients. The low sensitivity of 55% and low specificity of 74% for serology in our study (details not shown) suggest that this test is unreliable in isolation perhaps because of the B-cell defects seen in HIV infection. The low prevalence does not be due to antimicrobial or bismuth treatment and fits in with the low prevalence of duodenal ulcer disease in patients with AIDS.B The aetiology of dyspepsia in patients with HIV infection may differ from that in non-infected patients, the contribution of H pylori in HIV-positive patients being reduced. An alternative explanation is the impaired immune response in HIV infection. Spontaneous elimination of H pylori in immunocompetent patients does not seem to happen despite an adequate mucosal and circulating humoral response.9 Persistent chronic infection by H pylori may be due to occupation of an immunoprivileged site or to interference with the host’s cellular immune response9-indeed H pylori may have immunomodulatory activity against host T cells.lO If such cellular interaction is essential for the persistence of H pylori, the paucity of such cells in the antral mucosa of patients infected with HIV may account for our findings. Whatever the explanation, our findings do suggest that infection with HIV does not predispose patients to a greater risk of H pylori infection. seem to
We thank Dr D. Forman, Dr R. F. A.
Logan, and Dr J. Main.
Departments of Gastroenterology, Microbiology, Histopathology, Genitourinary Medicine, and Immunology, St Mary’s Hospital, London W2, UK, and University
Diagnostics Ltd, University College, London
R. P. H. LOGAN R. J. POLSON G. RAO M. M. WALKER S. PEDLEY J. R. W. HARRIS A. J. PINCHING J. H. BARON
EAJ, Langenberg W, Houthoff HJ, Zanen HC, Tytgat GNJ. Campylobacter pyloridis-associated chronic antral gastritis. Gastroenterology 1988; 94: 33-44. Goodwin CS. Duodenal ulcer, Campylobacter pylori, and the "leaking roof ’ concept.
Lancet 1988; ii: 1467-69. Jones DM, Eldridge J, Fox AJ, Sethi P, Whorwell PJ. Antibody
campylobacter-like organism (’Campylobacter pyloridis’), clinical correlations and distribution in the normal population. JMed Microbiol 1986; 22: 57-62. 4. Francis NDS, Logan RPH, Walker MM, et al. Campylobacter pylori organisms in the upper gastrointestinal tract of patients with HIV-1 infection. J Clin Pathol 1990; 43: 60-62.
5. Rotterdam H, Dieterich DT. Campylobacter pyloridis in AIDS patients a clinicopathological correlation. Am J Gastroenterol 1987; 82: 934 (abstr). 6. Edwards PD, Carrick J, Lee A, Mitchell H, Copper D, Turner J. Campylobacter pylori: not the major cause of histological gastritis in AIDS. Gastroenterology 1989; 94: 135 (abstr). 7. McMullen L, Walker MM, Bain LA, Karin NQ, Baron JHB. Histological identification of campylobacter using the Gimenez technique in gastric antral mucosa. J Clin Pathol 1987; 40: 464-65. 8. Logan RPH, Walker MM, Francis ND, et al. Campylobacter pylori in the acquired immunodeficiency syndrome. Gastroenterology 1989; 96: 1229. 9. Rathbone BJ, Wyatt JI, Heatley V. Immunological aspects of Campylobacter pylori infection. Eur J Gastroenterol Hepatol 1989; 1: 13-16. 10. Dzierzanowska D, Michalkiewicz J, Stachowski J, Rozynek E. Immunomodulatory effect of Campylobacter pylori on human lymphocyte proliferation. Klin Wschr 1989; 67 (suppl XVIII): 17.
definition for AIDS in Africa
case definition for AIDS in African children was World Health Organisation workshop at Bangui, Central African Republic, and later revised.l The aim was to provide a simple non-invasive method by which AIDS could be detected without serology. Reports on the use of this definition concentrate on specificity and sensitivity,2 but not on the ease of application. 65 paediatric inpatients at Kisiizi Hospital in south-