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High HCV prevalence in Egyptian blood donors
427
was tested for antibodies to HEV (ref 4 and with ELISA). Nineteen of the specimens were non-reactive. One specimen, from the above patient on the discharge date, was highly reactive. The reactive specimen was retested for antibodies to HEV in our ELISAs with synthetic peptides and was confirmed reactive. We investigated follow-up specimens with ELISA with each of four recombinant HEV antigens (table) that are useful for diagnosing HEV infections (ref 4 and our tests). IgM antibodies were detected on the discharge date about 7 weeks after the appearance of symptoms, but were no longer detected by inovember, 1991. IgG antibodies were detected in all four ELISAs
described above,
our
and continue
to
be detected in three of the four ELISAs; the last
specimen was taken nearly 41years after the acute-phase infection. Furthermore, over the testing period, the endpoint titre of IgG antibodies to M4-2 and B4-2 decreased four and eight-fold, respectively; the B3-2 antigen decreased two-fold. These data are contrary to the studiess,6 suggesting that the IgG antibodies against these antigens are short-lived and often become undetectable 6-12 months after an acute HEV infection. Because so few cases have been followed up for long periods, it is difficult to determine whether IgG antibodies to HEV are long-lived in most or only a few HEV infected patients. GEORGE J. DAWSON ISA K. MUSHAHWAR KURT H. CHAU
Experimental Biology Research, Abbott Laboratories, North Chicago, Illinois 60064, USA
UCLA Health Sciences, Los 1
GARY L. GITNICK
Angeles
Bradley DW Hepatitis non-A, non-B viruses become identified as hepatitis C and E viruses In Melnick JL, ed. Progress in medical virology, vol. 37, Basel: Karger, 1990; 101-35
2. Skidmore 3 4 5
SJ, Yarbough PO, Gabor KA,
et
al.
Imported hepatitis E
in
UK. Lancet
1991; 337: 1541 Bader TF, Krawczynski K, Polish LB, Favorov MO. Hepatitis E m a US traveller to Mexico Lancet 1991, 325: 1659 Yarbough PO, Tarn AW, Fry KE, et al Hepatitis E virus; identification of type-common epitopes J Virol 1991; 65: 5790-97 Goldsmith R, Yarbough PO, Reyes GR, et al Enzyme linked immunosorbent assay for diagnosis of acute sporadic hepatitis E in Egyptian children. Lancet 1992, 339:
g is the group size and q is 1 - prevalenCe.7,8 Therefore, optimum group size is inversely related to prevalence. We simulated 10 000 units with a conservative estimate of 17% positive:1 the optimum group size was 3. Tests would have to be completed on 7602 specimens instead of 10 000, a saving of 2398 tests. To ensure that the ELISA is sufficiently sensitive to detect contaminated sera in pools of 3, we serially diluted positive blood specimens in different lots of pooled negative sera, and assessed the dilutions at which positive sera could be detected. False negatives occurred in 5 of the 163 tests, all at dilutions greater than 1 in 3, which confirms the safety and potential savings of this approach. Since pooling increases efficiency when the prevalence of HCV contamination decreases, and the sensitivity of the ELISA is adequate for pooling at least 5 blood specimens in equal amounts, costs for testing in other countries or for other contaminants with lower prevalence can be minimised. Department of Clinical Pathology, University
MOAMENA A. KAMEL
Department of Medicine, Ain Shams University, Cairo
YASIN A. GHAFFAR
Cairo
of Clinical
Department University
Pathology,
MONA A. WASEF
Cairo
Mohandsm,
MARGRET WRIGHT
Cairo
Department of Family and University of Arizona
Community Medicine,
LARRY C. CLARK
Department of Public Health Sciences, University of Hawaii, Honolulu, Hawaii 96822, USA
F. DEWOLFE MILLER
1. Saeed AA, Al-Admawi AM, Al-Rasheed A, et al. Hepatitis C virus infection in Egyptian volunteer blood donors m Riyadh. Lancet 1991, 338: 459-60. 2. Kuhnl P, Seidl S, Stangel W, Beyer J, Sibrowski W, Flik J. Antibody to hepatitis C virus in German blood donors. Lancet 1989; ii: 324. 3. Janot C, Couroucé AM, Maniez M. Antibodies to hepatitis C virus in French blood donors. Lancet 1989; ii: 796-97. 4. Sirchia G, Bellobuono A, Giovanetti A, Marconi M. Antibodies to hepatitis C virus in Italian blood donors. Lancet 1989; ii: 797 5. Alter MJ, Sampliner RE Hepatitis C and miles to go before we sleep. N Engl Med J
1989; 321: 1538-40.
328-31
B’A, Ticehurst J, Sreenivasan MA, et al Aetiological association of a virus-like particle with enterically transmitted non-A, non-B hepatitis. Lancet 1988; i: 550-54
b Arankalle
High HCV prevalence in Egyptian blood
6. Weiner AJ, Truett MA, Han J, et al. HCV testing in low-risk population. Lancet 1990; 336: 695. 7. Dorfman B The detection of defective members of large populations. Ann Math Statist 1943, 14: 326-440 8. Federer WT Statistics and society data collection and interpretation. 2nd ed. New York. Marcel Dekker, 1991: 600.
donors SiR,—The report by Saeed et all prompted us to examine hepatitis C virus (HCV) positivity in 2164 apparently healthy, male uruversity students, aged 20-27, who each donated one unit of blood in January-May, 1992. We found 10-9% positive by Abbott ELISA, 89% of which were confirmed positive by supplemental testing. Since these students were unpaid donors and generally middle-class, the prevalence of HCV positivity in paid donors may be much higher. In other countries, the prevalence of HCV contamination in healthy blood donors ranged from zero to 2%.* The factors that contribute to our high prevalence are unknown. The prevalence of HBsAg was lower in this group of students (3-4%). Of the 73 positive, 9 were confirmed for both HCV antibody and HBsAg. The likelihood (odds ratio) for having both infections was 1-33 (95% CI 0’61-2’81). This lack of association suggests different risk factors and routes of transmission for these in this group. Although all blood donations in Egypt are routinely screened for HBsAg and HIV-1and HIV-2, HCV is not included. About half those infected with HCV are at high risk of cirrhosis in 3-5 years’ time.’ About 400 000 units of blood are transfused annually in Egypt. Since ELISA-confirmed HCV positivity is frequently viraemic,6 potentially 10% of the recipients could contract HCV infection. Routine screening for HCV in Egyptian blood donors is urgently needed. Because HCV testing is expensive, we have investigated pooling blood to reduce costs. The optimum size to pool depends on the prevalence of positive units and the sensitivity of the test. The break-even point, the prevalence at which it is no longer costeffective to pool, can be determined from: g2 1 /(qZ In[l/q]), where
two viruses
=
Myocarditis caused by Chlamydia pneumoniae (TWAR) and sudden unexpected death in a Swedish elite orienteer SiR,—Six Swedish elite orienteers aged 17-29 years, five male one female, have been struck by sudden unexpected death (SUD) during competition or training in the past 3 years, the latest case occurring in June, 1992. All had occasionally been training together within the same geographical area. With about 200 orienteers qualified on the international elite level, this corresponds to an annual mortality rate of 1 %. No similar clustering of cases has
and
been recorded within other competitive sports in Sweden. Degenerative changes, small lymphocytic infiltrates, and patchy fibrosis were found in the myocardium of all six cases on necropsy. No other cardiac abnormalities often associated with SUD in young sportsmen, such as hypertrophic cardiomyopathy, coronary artery abnormality, or significant coronary artery or valvular disease, were found;’ one case that was initially classified as obstructive cardiomyopathy is now being re-evaluated. Myocarditis has been reported to be the cause of SUD in young sportsmen in only about 12% of cases.’ The most recent of our six cases was a 26-year-old man, who had been active in orienteering since he was a teenager. There were no notable diseases in his history. In December, 1991, he had fainted during exertion. Investigation showed symptoms and signs suggestive of ongoing myocarditis and he was advised to rest. In April he had pneumonia and was prescribed phenoxymethylpenicillin. He gradually recuperated but cough lasted almost 2 months, during which he refrained from physical training. On June
was tested for antibodies to HEV (ref 4 and with ELISA). Nineteen of the specimens were non-reactive. One specimen, from the above patient on the discharge date, was highly reactive. The reactive specimen was retested for antibodies to HEV in our ELISAs with synthetic peptides and was confirmed reactive. We investigated follow-up specimens with ELISA with each of four recombinant HEV antigens (table) that are useful for diagnosing HEV infections (ref 4 and our tests). IgM antibodies were detected on the discharge date about 7 weeks after the appearance of symptoms, but were no longer detected by inovember, 1991. IgG antibodies were detected in all four ELISAs
described above,
our
and continue
to
be detected in three of the four ELISAs; the last
specimen was taken nearly 41years after the acute-phase infection. Furthermore, over the testing period, the endpoint titre of IgG antibodies to M4-2 and B4-2 decreased four and eight-fold, respectively; the B3-2 antigen decreased two-fold. These data are contrary to the studiess,6 suggesting that the IgG antibodies against these antigens are short-lived and often become undetectable 6-12 months after an acute HEV infection. Because so few cases have been followed up for long periods, it is difficult to determine whether IgG antibodies to HEV are long-lived in most or only a few HEV infected patients. GEORGE J. DAWSON ISA K. MUSHAHWAR KURT H. CHAU
Experimental Biology Research, Abbott Laboratories, North Chicago, Illinois 60064, USA
UCLA Health Sciences, Los 1
GARY L. GITNICK
Angeles
Bradley DW Hepatitis non-A, non-B viruses become identified as hepatitis C and E viruses In Melnick JL, ed. Progress in medical virology, vol. 37, Basel: Karger, 1990; 101-35
2. Skidmore 3 4 5
SJ, Yarbough PO, Gabor KA,
et
al.
Imported hepatitis E
in
UK. Lancet
1991; 337: 1541 Bader TF, Krawczynski K, Polish LB, Favorov MO. Hepatitis E m a US traveller to Mexico Lancet 1991, 325: 1659 Yarbough PO, Tarn AW, Fry KE, et al Hepatitis E virus; identification of type-common epitopes J Virol 1991; 65: 5790-97 Goldsmith R, Yarbough PO, Reyes GR, et al Enzyme linked immunosorbent assay for diagnosis of acute sporadic hepatitis E in Egyptian children. Lancet 1992, 339:
g is the group size and q is 1 - prevalenCe.7,8 Therefore, optimum group size is inversely related to prevalence. We simulated 10 000 units with a conservative estimate of 17% positive:1 the optimum group size was 3. Tests would have to be completed on 7602 specimens instead of 10 000, a saving of 2398 tests. To ensure that the ELISA is sufficiently sensitive to detect contaminated sera in pools of 3, we serially diluted positive blood specimens in different lots of pooled negative sera, and assessed the dilutions at which positive sera could be detected. False negatives occurred in 5 of the 163 tests, all at dilutions greater than 1 in 3, which confirms the safety and potential savings of this approach. Since pooling increases efficiency when the prevalence of HCV contamination decreases, and the sensitivity of the ELISA is adequate for pooling at least 5 blood specimens in equal amounts, costs for testing in other countries or for other contaminants with lower prevalence can be minimised. Department of Clinical Pathology, University
MOAMENA A. KAMEL
Department of Medicine, Ain Shams University, Cairo
YASIN A. GHAFFAR
Cairo
of Clinical
Department University
Pathology,
MONA A. WASEF
Cairo
Mohandsm,
MARGRET WRIGHT
Cairo
Department of Family and University of Arizona
Community Medicine,
LARRY C. CLARK
Department of Public Health Sciences, University of Hawaii, Honolulu, Hawaii 96822, USA
F. DEWOLFE MILLER
1. Saeed AA, Al-Admawi AM, Al-Rasheed A, et al. Hepatitis C virus infection in Egyptian volunteer blood donors m Riyadh. Lancet 1991, 338: 459-60. 2. Kuhnl P, Seidl S, Stangel W, Beyer J, Sibrowski W, Flik J. Antibody to hepatitis C virus in German blood donors. Lancet 1989; ii: 324. 3. Janot C, Couroucé AM, Maniez M. Antibodies to hepatitis C virus in French blood donors. Lancet 1989; ii: 796-97. 4. Sirchia G, Bellobuono A, Giovanetti A, Marconi M. Antibodies to hepatitis C virus in Italian blood donors. Lancet 1989; ii: 797 5. Alter MJ, Sampliner RE Hepatitis C and miles to go before we sleep. N Engl Med J
1989; 321: 1538-40.
328-31
B’A, Ticehurst J, Sreenivasan MA, et al Aetiological association of a virus-like particle with enterically transmitted non-A, non-B hepatitis. Lancet 1988; i: 550-54
b Arankalle
High HCV prevalence in Egyptian blood
6. Weiner AJ, Truett MA, Han J, et al. HCV testing in low-risk population. Lancet 1990; 336: 695. 7. Dorfman B The detection of defective members of large populations. Ann Math Statist 1943, 14: 326-440 8. Federer WT Statistics and society data collection and interpretation. 2nd ed. New York. Marcel Dekker, 1991: 600.
donors SiR,—The report by Saeed et all prompted us to examine hepatitis C virus (HCV) positivity in 2164 apparently healthy, male uruversity students, aged 20-27, who each donated one unit of blood in January-May, 1992. We found 10-9% positive by Abbott ELISA, 89% of which were confirmed positive by supplemental testing. Since these students were unpaid donors and generally middle-class, the prevalence of HCV positivity in paid donors may be much higher. In other countries, the prevalence of HCV contamination in healthy blood donors ranged from zero to 2%.* The factors that contribute to our high prevalence are unknown. The prevalence of HBsAg was lower in this group of students (3-4%). Of the 73 positive, 9 were confirmed for both HCV antibody and HBsAg. The likelihood (odds ratio) for having both infections was 1-33 (95% CI 0’61-2’81). This lack of association suggests different risk factors and routes of transmission for these in this group. Although all blood donations in Egypt are routinely screened for HBsAg and HIV-1and HIV-2, HCV is not included. About half those infected with HCV are at high risk of cirrhosis in 3-5 years’ time.’ About 400 000 units of blood are transfused annually in Egypt. Since ELISA-confirmed HCV positivity is frequently viraemic,6 potentially 10% of the recipients could contract HCV infection. Routine screening for HCV in Egyptian blood donors is urgently needed. Because HCV testing is expensive, we have investigated pooling blood to reduce costs. The optimum size to pool depends on the prevalence of positive units and the sensitivity of the test. The break-even point, the prevalence at which it is no longer costeffective to pool, can be determined from: g2 1 /(qZ In[l/q]), where
two viruses
=
Myocarditis caused by Chlamydia pneumoniae (TWAR) and sudden unexpected death in a Swedish elite orienteer SiR,—Six Swedish elite orienteers aged 17-29 years, five male one female, have been struck by sudden unexpected death (SUD) during competition or training in the past 3 years, the latest case occurring in June, 1992. All had occasionally been training together within the same geographical area. With about 200 orienteers qualified on the international elite level, this corresponds to an annual mortality rate of 1 %. No similar clustering of cases has
and
been recorded within other competitive sports in Sweden. Degenerative changes, small lymphocytic infiltrates, and patchy fibrosis were found in the myocardium of all six cases on necropsy. No other cardiac abnormalities often associated with SUD in young sportsmen, such as hypertrophic cardiomyopathy, coronary artery abnormality, or significant coronary artery or valvular disease, were found;’ one case that was initially classified as obstructive cardiomyopathy is now being re-evaluated. Myocarditis has been reported to be the cause of SUD in young sportsmen in only about 12% of cases.’ The most recent of our six cases was a 26-year-old man, who had been active in orienteering since he was a teenager. There were no notable diseases in his history. In December, 1991, he had fainted during exertion. Investigation showed symptoms and signs suggestive of ongoing myocarditis and he was advised to rest. In April he had pneumonia and was prescribed phenoxymethylpenicillin. He gradually recuperated but cough lasted almost 2 months, during which he refrained from physical training. On June