ityll.12 (whole-blood viscosity can be lower than normal, probably a compensatory response’3 aimed at the integrity of the
ABSENCE OF VIRUS STRUCTURES IN CROHN’S DISEASE TISSUES STUDIED BY ELECTRON MICROSCOPY
microcirculation), but the role of fibrinogen is far from simple. Your editorial on hyperviscosity in disease covers the state of art nearer to
1975 than 1977.
Kanematsu Memorial
Institute,
Sydney Hospital, Sydney 2000, Australia
L. DINTENFASS
ROTAVIRUS INFECTION IN HIGH-INCIDENCE
LACTASE-DEFICIENCY POPULATION
SIR,-It has been postulated that lactase in the brush border of intestinal epithelial cells acts both as a receptor site and an uncoating enzyme for rotavirus.’ This hypothesis is based on the in-vitro ability of purified p-galactosidase to remove the outer capsid layer of the virus and could explain the tendency of rotavirus to infect infant animals and involve only gut epithelial cells. The incidence of persistent high intestinal lactase activity is low in certain ethnic groups. Of 20 Johannesburg Blacks of unspecified tribe, all were found to be deficient.2 Similarly, 13 Swazi, 4 Tswana, 50 Damara, and 5 Dama were all deficient,3 and of 58 Herero all but 2 were deficient.4 Only 1 of 40 Kalahari San ("bushmen") was lactose tolerant. The prevalence of rotavirus infection in these populations would thus provide an indication of the relative importance of lactase in the pathogenesis of rotavirus gastroenteritis. Our initial electronmicroscopic investigations of Black infantile gastroenteritis inpatients, all under the age of 2 years, showed a low incidence of 6-16%. However, by complement fixation tests, 69% of patients proved to be rotavirus positive7 a figure comparable with that in White communities in North America, the United Kingdom, and Australia.9 In addition, a seroepidemiological survey showed that Blacks had a more extensive exposure to rotavirus than Whites;’° rotavirus antibodies, measured by immunofluorescence, were present in 87 of 94 (93%) adult Blacks compared with 72 of 94 (77%) adult Whites (p
328
ityll.12 (whole-blood viscosity can be lower than normal, probably a compensatory response’3 aimed at the integrity of the
ABSENCE OF VIRUS STRU...