One hundred and forty-three multitransfused patients with hereditary haemostatic disorders were examined for evidence of disease related to the acquired immune deficiency syndrome (AIDS). Ninety-nine patients with severe haemophilia A were tested for anti-HTLV-III and 76 were found to be positive. All except one of these seropositive patients had received commercial factor VIII concentrates at some time. Eighteen patients with haemophilia B were tested and all were anti-HTLV-III negative. Three out of 36 sexual partners of patients with haemophilia A positive for anti-HTLV-III were also seropositive. One, who had recently received blood transfusions, had AIDS with Pneumocystis carinii pneumonia. Three patients with severe haemophilia A died from Aids. A further 30 haemophiliacs had AIDS related complex or lymphadenopathy that could be related to HTLV-III infection. There was a significant correlation between lymphadenopathy and anti-HTLV-III seropositivity. No evidence of casual spread of AIDS was found since all 68 health care staff tested were anti-HTLV-III negative, including three surgeons who regularly worked with patients positive for anti-HTLV-III. The resources devoted to counselling and laboratory support in centres treating people at risk and their families need to be urgently reassessed.

Alow-speed centrifugation technique forthepreparation ofgrids after minimal purification offecal extracts isdescribed forexamination ofviruses bydirect electron microscopy usingnegative staining. Results showedthatadenovirus, astrovirus, rotavirus, and"small round"viruses werefrequently shedintothe gastrointestinal tract inclumps ofvariable size. Differential centrifugation study showedthatasubstantial proportion ofthevirus inthesample waslost inthe initial pellet atthefirst stepofclarification; thisfinding casts doubtonthe validity ofimmuneelectron microscopy fordirect typing ofstrains ofthese viruses fromstools. Inaddition, particle counts based onconventional specimen processingarelikely togrossly underestimate thetruevalue. Theviruses mostfrequently implicated in nonbacterial gastroenteritis arerotavirus and adenovirus (2-5, 7,14). Withonerecent exception(23), numerousprevious attempts topropagate humanrotavirus tohigh titer invitro have failed (1,15,21,24), andonlya fewanimal rotaviruses havebeenadapted togrowincell cultures (12, 13). Adenoviruses associated with diarrhea, often seeninlarge numbers withthe electron microscope, donotreadily growintissueculture (7). Therefore, examination ofstools byelectron microscopy forviruses hasbecome aroutine method. Manyinvestigators haveused immuneelectron microscopy either toincrease thesensitivity ofdetection ortotypeviruses directly fromthestools (6, 8,9).Someelectron microscopy techniques rely onclarification of fecal suspension byspinning at3,000 to4,000 rpmfor20to30minwithsubsequent ultracentrifugation ofsupernatant fluids at180,000 to 249,000 X g (6,11,25). However, ithasbeen shown(16) thatlarge- andmedium-sized viruses, evenassingle particles, sediment atarelatively lowgravitational force(2,100 x g).Morerecently, after thelow-speed centrifugation technique after minimal purification offecal extracts was used, rotaviruses havefrequently been foundinalarge proportion ofpatients inclumps ofvariable size, often larger thanabacterial cell (17). Routinely, higher forces thannecessary are usedforclarification offecal suspensions, and thusviruses maybelost intheinitial pellet. The present investigation wascarried outtodeterminewhether clarification bycentrifugation results inloss ofvirus andwhether other viruses found infeces arealso shedinclumps.