1316 mal human
lymphocytes? Our experience indicates that an example of "in vitro veritas", an observation with theoretical and practical implications, and that it provides another test of non-T cell activity in man. S.L.M.C.
may be
National Jewish Hospital and Research Center, 3800 East Colfax Street, Denver, Colorado 80206, U.S.A. WOJCIECH
faces remains inferential, the reality of the threat per appear
se
would
increasingly credible.
Veterans Administration
Hospital,
Jamaica Plain, Boston, Massachusetts 02130, U.S.A.
R. H. SEDER P. M. DESAI R. S. KOFF
KONSTANTY PODLESKI
LABORATORY-ACQUIRED HEPATITIS B SIR,-During 1974, two laboratory workers in this hospital developed symptoms and signs of acute viral hepatitis; both had sera positive for HBsAg by radioimmunoassay. Both made good clinical recoveries, although one continues to be a symptom-free carrier of HBsAg. Since neither worker could recall a specific occupational or other parenteral exposure to materials known to be contaminated with HB virus, we considered the possibility that non-parenteral exposure might be responsible for transmission. To assess the probability of this mode of spread, we tested working surfaces and workers’ hands for contamination with HBsAg. Using the simple method of Favero et al.,’2 we swabbed multiple sites in the several laboratory rooms and eluted the pre-moistened swabs with 1 ml of a 1% solution of human serum-albumin. The eluates were then tested for HBsAg by radioimmunoassay. Of the first 20 specimens 2 were HBsAg positive, 1 at a relatively low level from the bench where sera are poured and stored after centrifuging, the other with a high count from an area near the blood-bank microscope where Coombs test crossmatch suspensions are poured from tube to slide for micro-
scopic inspection. 40 additional specimens subsequently taken from other laboratory sites and reassay of the contaminated spots yielded positive findings only from the serum pour-off bench. Each of 4 adjacent sites on this bench top carried approximately equal amounts of HBsAg, and all were rendered negative for HBsAg (within the sensitivity limits of the assay) by scrubbing for half a minute with 5% sodium hypochlorite solution ("5% available chlorine"). (The scrub and HBsAg-negative swabs followed the positive reassay immediately, before knowledge of the repeat positive findings.) We next swabbed the fingertips of ten laboratory workers after they had poured off the day’s serum collection, a total of approximately 200 blood specimens. Swabs from both before and after hand washing yielded only negative results. The extensively contaminated pour-off bench is the site where the sera from each day’s blood specimens are openly poured into small plastic cups. Sera are stored uncapped on this bench for several hours. The first employee to develop HBsAg-associated hepatitis was the supervisor of this operation. The second was an evening-shift worker who spent much of his time in the same area. Because of the possibility that the contaminated site was directly related to the illness of these two workers, we instituted the use of disposable absorbent pads under the racks of serum and the periodic cleaning of the bench with hypochlorite. No new cases have developed among our laboratory workers in the subsequent fifteen months. Although hypochlorite is widely supposed to be an effective anti-H.B.v. agent 3- its mechanism of action is unclear. Our assays, however, demonstrate that mechanical scrubbing with hypochlorite does reduce and possibly eliminates HBsAg from environmental surfaces. Although its reduction of the threat to laboratory-worker health posed by H.B.v.-contaminated sur-
YERSINIA INFECTION WITH HEPATITIS IN A PHYSICIAN
SIR,- Yersinia enterocolitica infection is increasingly in man. Pets and domestic animals were thought to be the natural reservoir for infection, but there have been reports of interfamilial’ and even hospitaP outbreaks. I describe here a case of Y. enterocolitica infection in a previously healthy 31-year-old male paediatrician who had yersinitis after doing more than thirty intestinal biopsies on children with diarrhoea. His anti-Yersinia titre was 1/10 000; erythrocyte-sedimentation rate 125 mm/h (first). He had prolonged diarrhoea, arthritis in both knees and ankles. He had HLA type A2, B12, not the usual B27 as described by Aho et al. in Yersinia arthritis. He had prostatitis and clinically and laboratory verified HBAg-negative hepatitis. Hepatitis has not been reported as a complication of Yersinia infection4though liver abscesses have been described.6 Hospital staff should take hygienic precautions when handling patients with diarrhoea of unknown cause, and especially in verified cases of Yersinia infection. Special care should be taken with investigations such as gastrointestinal endoscopy and biopsy.
common
Paediatric Department,
Rikshospitalet, University of Oslo, Oslo, Norway.
ARNE F. BAKKEN
SCREENING FOR BREAST CANCER
SiR,—Ido not consider the high incidence of cancer demon-
by the West London Breast Cancer Screening Study (Nov. 22, p. 1026) surprising. The authors did not have access to all women over 40 in their borough, and they did not report on the incidence of breast cancer for this population. The women in the study were a selected group who had chosen to make use of the proffered service. Of this group, 1 in 5 had some reason for believing themselves to be at risk of breast disease (known bias). The remaining 4 out of 5 women, ignoring the other risk factors which might coexist with the first-mentioned, may have been responding to cues not yet clearly identified in the medical evaluation system. Let us simply say that this remaining group was somewhat different from the total population (unknown bias). In any screening test, whatever was being sought would be expected to have a higher incidence in a group of people who considered themselves to be at risk. Assumptions about the yield of subsequent examination of the study population should not be made. These workers may well be seeing, fortuitously, the early courses of both rapidly and slowly evolving malignancies. Now to be documented are the patterns of survival of those with early disease demonstrated at the first attendance for screening and those with disease demonstrated at subsequent screenings. strated
Columbia
University-Harlem Hospital Center, Department of Rehabilitation Medicine, New York, N.Y. U.S.A.
10037,
A. D. ANDERSON
1.
S., Maynard, J. E., Petersen, N. J., Boyer, K. M., Bond, W. W., Berquist, K. R., Szmuness, W. Lancet, 1973, ii, 1455. 2. Favero, M. S., Bond, W. W., Petersen, N. J., Berquist, K. R., Maynard, J. E. J. infect. Dis. 1974, 129, 210. 3. Bond, W. W., Pattison, C. P. J. Am. med. Ass. 1975, 231, 700. 4. Percy-Robb, I. W., Proffitt, J., Whitby, L. G. J. clin. Path. 1970, 23, 751. 5. Marmion, B. P., Tonkin, R. W. Br. Med. Bull. 1972, 28, 169. 1. Favero, M.
Gutman, L. T., Ottesen, E. A., Quan, T. J., Noce, P. S., Katz, S. L. New Engl. J. Med. 1973, 288, 1372. 2. Toivanen, P., Toivanen, A., Olkkonen, L., Aantaa, S. Lancet, 1973, i, 801. 3. Aho, K., Ahvonen, P., Lassus, A., Sievers, K., Tilikainen, A. ibid. 1973, ii, 157. 4.
Hällström, K., Sairanen, E., Ohela, K. Acta med. scand. 1972, 191, 485. 5. Larsen, J. H. Ugeskr. Lœg. 1975, 137, 565. 6. Rabson, A. R., Hallett, A. F., Koornhof, H. J. J. infect. Dis. 1975, 131, 447.
lymphocytes? Our experience indicates that an example of "in vitro veritas", an observation with theoretical and practical implications, and that it provides another test of non-T cell activity in man. S.L.M.C.
may be
National Jewish Hospital and Research Center, 3800 East Colfax Street, Denver, Colorado 80206, U.S.A. WOJCIECH
faces remains inferential, the reality of the threat per appear
se
would
increasingly credible.
Veterans Administration
Hospital,
Jamaica Plain, Boston, Massachusetts 02130, U.S.A.
R. H. SEDER P. M. DESAI R. S. KOFF
KONSTANTY PODLESKI
LABORATORY-ACQUIRED HEPATITIS B SIR,-During 1974, two laboratory workers in this hospital developed symptoms and signs of acute viral hepatitis; both had sera positive for HBsAg by radioimmunoassay. Both made good clinical recoveries, although one continues to be a symptom-free carrier of HBsAg. Since neither worker could recall a specific occupational or other parenteral exposure to materials known to be contaminated with HB virus, we considered the possibility that non-parenteral exposure might be responsible for transmission. To assess the probability of this mode of spread, we tested working surfaces and workers’ hands for contamination with HBsAg. Using the simple method of Favero et al.,’2 we swabbed multiple sites in the several laboratory rooms and eluted the pre-moistened swabs with 1 ml of a 1% solution of human serum-albumin. The eluates were then tested for HBsAg by radioimmunoassay. Of the first 20 specimens 2 were HBsAg positive, 1 at a relatively low level from the bench where sera are poured and stored after centrifuging, the other with a high count from an area near the blood-bank microscope where Coombs test crossmatch suspensions are poured from tube to slide for micro-
scopic inspection. 40 additional specimens subsequently taken from other laboratory sites and reassay of the contaminated spots yielded positive findings only from the serum pour-off bench. Each of 4 adjacent sites on this bench top carried approximately equal amounts of HBsAg, and all were rendered negative for HBsAg (within the sensitivity limits of the assay) by scrubbing for half a minute with 5% sodium hypochlorite solution ("5% available chlorine"). (The scrub and HBsAg-negative swabs followed the positive reassay immediately, before knowledge of the repeat positive findings.) We next swabbed the fingertips of ten laboratory workers after they had poured off the day’s serum collection, a total of approximately 200 blood specimens. Swabs from both before and after hand washing yielded only negative results. The extensively contaminated pour-off bench is the site where the sera from each day’s blood specimens are openly poured into small plastic cups. Sera are stored uncapped on this bench for several hours. The first employee to develop HBsAg-associated hepatitis was the supervisor of this operation. The second was an evening-shift worker who spent much of his time in the same area. Because of the possibility that the contaminated site was directly related to the illness of these two workers, we instituted the use of disposable absorbent pads under the racks of serum and the periodic cleaning of the bench with hypochlorite. No new cases have developed among our laboratory workers in the subsequent fifteen months. Although hypochlorite is widely supposed to be an effective anti-H.B.v. agent 3- its mechanism of action is unclear. Our assays, however, demonstrate that mechanical scrubbing with hypochlorite does reduce and possibly eliminates HBsAg from environmental surfaces. Although its reduction of the threat to laboratory-worker health posed by H.B.v.-contaminated sur-
YERSINIA INFECTION WITH HEPATITIS IN A PHYSICIAN
SIR,- Yersinia enterocolitica infection is increasingly in man. Pets and domestic animals were thought to be the natural reservoir for infection, but there have been reports of interfamilial’ and even hospitaP outbreaks. I describe here a case of Y. enterocolitica infection in a previously healthy 31-year-old male paediatrician who had yersinitis after doing more than thirty intestinal biopsies on children with diarrhoea. His anti-Yersinia titre was 1/10 000; erythrocyte-sedimentation rate 125 mm/h (first). He had prolonged diarrhoea, arthritis in both knees and ankles. He had HLA type A2, B12, not the usual B27 as described by Aho et al. in Yersinia arthritis. He had prostatitis and clinically and laboratory verified HBAg-negative hepatitis. Hepatitis has not been reported as a complication of Yersinia infection4though liver abscesses have been described.6 Hospital staff should take hygienic precautions when handling patients with diarrhoea of unknown cause, and especially in verified cases of Yersinia infection. Special care should be taken with investigations such as gastrointestinal endoscopy and biopsy.
common
Paediatric Department,
Rikshospitalet, University of Oslo, Oslo, Norway.
ARNE F. BAKKEN
SCREENING FOR BREAST CANCER
SiR,—Ido not consider the high incidence of cancer demon-
by the West London Breast Cancer Screening Study (Nov. 22, p. 1026) surprising. The authors did not have access to all women over 40 in their borough, and they did not report on the incidence of breast cancer for this population. The women in the study were a selected group who had chosen to make use of the proffered service. Of this group, 1 in 5 had some reason for believing themselves to be at risk of breast disease (known bias). The remaining 4 out of 5 women, ignoring the other risk factors which might coexist with the first-mentioned, may have been responding to cues not yet clearly identified in the medical evaluation system. Let us simply say that this remaining group was somewhat different from the total population (unknown bias). In any screening test, whatever was being sought would be expected to have a higher incidence in a group of people who considered themselves to be at risk. Assumptions about the yield of subsequent examination of the study population should not be made. These workers may well be seeing, fortuitously, the early courses of both rapidly and slowly evolving malignancies. Now to be documented are the patterns of survival of those with early disease demonstrated at the first attendance for screening and those with disease demonstrated at subsequent screenings. strated
Columbia
University-Harlem Hospital Center, Department of Rehabilitation Medicine, New York, N.Y. U.S.A.
10037,
A. D. ANDERSON
1.
S., Maynard, J. E., Petersen, N. J., Boyer, K. M., Bond, W. W., Berquist, K. R., Szmuness, W. Lancet, 1973, ii, 1455. 2. Favero, M. S., Bond, W. W., Petersen, N. J., Berquist, K. R., Maynard, J. E. J. infect. Dis. 1974, 129, 210. 3. Bond, W. W., Pattison, C. P. J. Am. med. Ass. 1975, 231, 700. 4. Percy-Robb, I. W., Proffitt, J., Whitby, L. G. J. clin. Path. 1970, 23, 751. 5. Marmion, B. P., Tonkin, R. W. Br. Med. Bull. 1972, 28, 169. 1. Favero, M.
Gutman, L. T., Ottesen, E. A., Quan, T. J., Noce, P. S., Katz, S. L. New Engl. J. Med. 1973, 288, 1372. 2. Toivanen, P., Toivanen, A., Olkkonen, L., Aantaa, S. Lancet, 1973, i, 801. 3. Aho, K., Ahvonen, P., Lassus, A., Sievers, K., Tilikainen, A. ibid. 1973, ii, 157. 4.
Hällström, K., Sairanen, E., Ohela, K. Acta med. scand. 1972, 191, 485. 5. Larsen, J. H. Ugeskr. Lœg. 1975, 137, 565. 6. Rabson, A. R., Hallett, A. F., Koornhof, H. J. J. infect. Dis. 1975, 131, 447.
