793
The limitation of GTS is its reduced consistency to detect cases with very low parasite densities. However, GTS still serves as a useful standard because false positivity by GTS (given that a gold standard existed) can reasonably be assumed to be negligible with expert reading. This implies that if QBC is definitely more sensitive than GTS, a sensitivity of 100% should always be attained, independent of parasite density. When positive specimens are predominantly of low (as opposed to high) parasitaemia, QBC sensitivity is known to become lower and is often accompanied by so-called false positivity. False positivity by QBC should be interpreted along with its sensitivity. A review of the data in study 6 showed, for the corresponding sensitivity value reported, 4 false positives by QBC that were later confirmed to be true positives (table). This is equal to the number of positives by GTS alone (19—15=4). It is therefore more sensible to conclude that, despite its relatively low sensitivity (with reference to GTS, 789%), QBC is capable of detecting as many malaria cases as is GTS. If the trade-off between cases detected by one technique but not by the other is acceptable, QBC may be thought of as being as sensitive as GTS in this instance. Similarly, QBC is slightly more sensitive in study 4 (8 vs 188 - 182 6) and slightly less sensitive in study 5B (2 vs =
100-96=4). In general we are satisfied with the overall sensitivity of QBC in the field. It is the limitation in species differentiation (4, 5A, 6) that is of concern.
haemophilia itself or its treatment with concentrates would have to be considered. We have had experience with pasteurised factor VIII concentrates from Behringwerke (Factor VIII HS/Haemate HS and Beriate HS) since 1979. We have seen 27 haemophiliacs, all under 15 years, who have been treated exclusively with these preparations and have never received blood or other blood products. All these patients are anti-HIV-negative and none of them has so far demonstrated hepatitis C positivity. All 27 patients have been vaccinated against hepatitis B. Only larger prospective infection studies involving, for comparison, a control group of corresponding age that has not been treated with blood or blood derivatives can, in our opinion, quantify the very low residual risk of therapy-induced hepatitis transmission that may still exist. Observations of isolated cases should not be overevaluated. Department of Paediatrics, University of Munster, D-4400 Munster, Germany
H. POLLMANN
H. JÜRGENS
1. Takahashi M, Yamada G, Tsuji T. Intrafamilial transmission of hepatitis C. Gastroenterol Jpn 1991; 26: 483-88. 2. Velazquez O, Stetler HC, Avila C, et al. Epidemic transmission of enterically transmitted non-A, non-B hepatitis in Mexico, 1986-1987. JAMA 1990, 263: 3281-85. 3. Mele A, Rosmini F, Zampieri A, Gill ON. Integrated epidemiological system for acute viral hepatitis in Italy (SEIEVA): description and preliminary results Eur J Epidemiol 1986; 2: 300-04.
Department of Immunology and Parasitology, Armed Forces Research Institute of Medical Sciences, Bangkok 10400, Thailand
Dairy fat intake in Finland CHANSUDA WONGSRICHANALAI
Department of Internal Medicine, Pra Pokklao Provincial Hospital,
VITHAYAT NAMSIRIPONGPUN
Chanthaburi of
Department Biochemistry, Royal Thai Army Medical School, Pra Mongkutklao Army Hospital, Bangkok
JATURAPORN PORNSILAPATIP
Department of Immunology and Parasitology, Armed Forces Research Institute of Medical Sciences
DENNIS E. KYLE
Queen Saovabha Memorial Institute, Thai Red Cross Society,
HENRY WILDE
Bangkok
G, Martet G, et al. Quantitative buffy coat (QBC test), monofluo kit falciparum: comparative value in the rapid diagnosis of malaria. Mèd Trop 1990; 50: 97-101. 2. Pornsilapatip J, Namsiripongpun V, Wilde H, Hanvanich M, Chutivongse S. Detection of plasmodia m acridine orange stained capillary tubes (the QBC system). SE Asian J Trop Med Publ Health 1990; 21: 534-40. 3 Namsiripongpun V, Pansamdaeng P, Boonyawantana V, Pomsmlapatip J, Wilde H. The acridine orange stained capillary tubes (the QBC system) in diagnosis of malaria, a field trial. J Prapokklao Hosp Clin Med Educ Center (Chanthaburi, Thailand) 1990; 7: 78-83. 4. Wongsrichanalai C, Chuanak N, Webster HK, Prasittisuk M. Accuracy and practical use of acridine orange fluorescent microscopy of centrifuged blood (QBC malaria test) in patients attending malaria clinics in Thailand. SE Asian J Trop Med Publ Health (in press). 5 Rickman LS, Long GW, Oberst R, et al. Rapid diagnosis of malaria by acridine orange staining of centrifuged parasites. Lancet 1989; i 68-71. 6. Wongsrichanalai C, Pornsilapatip J, Namsiripongpun V, et al Acridine orange fluorescent microscopy and the detection of malaria in low density parasitemia. Am J Trop Med Hyg 1991; 44: 17-20. 1. Parzy D, Raphenon
Transmission of hepatitis in haemophiliacs SIR,-Dr Schulman and colleagues (Aug 1, p 305) describe a case of hepatitis C virus (HCV) transmission after the patient had received a pasteurised factor VIII product. In our view such descriptions of isolated cases do little to elucidate the often discussed residual risk of transmission after replacement of the virusinactivated factor concentrates. We fear that both the doctor and the patient will be put into a state of uncertainty by isolated retrospective observations. Isolated observations of HCV infection in haemophilic patients are to be expected since this infection is not exclusively associated with the transmission of blood or blood derivatives.1-3 If no further cases of hepatitis infection in
haemophiliacs
were
to
occur,
protection against hepatitis by
SIR,-Dr Renaud and Dr de Lorgeril (June 20, p 1523) present data on the consumption of dairy fat in 17 OECD (Organisation for Economic Cooperation and Development) countries and compared dairy fat intake with mortality from coronary heart disease. In their fig 1 the intake of dairy fat in Finland is much greater than we calculated from OECD food consumption statistics.’ According to the OECD report’ the average dairy fat consumption (including fat from milk and milk products, cheese, butter, and buttervegetable oil mixtures) in Finland in 1980-85 was 54 g daily which yields 484 kcal. The national food balance sheets of 1980-852 indicate an average intake of 58 g daily dairy fat in Finland, yielding 525 kcal. Renaud and de Lorgeril suggest over 800 cal (we assume that this means kcal) for Finland. The intake of dairy fat in the other Nordic countries also seems to be too high in Renaud and de Lorgeril’s study according to a recent Nordic conference (Nordic Dairy Congress, Odense, Denmark, June 15-18,1992) and to our calculations based on OECD statistics. Valio Reseach and Development Centre, PO Box 390, 00101 Helsinki, Finland
RIITTA KORPELA TUULA VESA
Economic Co-operation and Development. Food consumption 1979-1988 Paris: Publications Service, 1991. 2. Agricultural price indices, total calculations, total margins for farm products, and balance sheets for food 1980-1986 Helsinki. VAPK Kampin VALTIMO, 1988. 1
Organization for statistics
***This letter has been shown to Dr Renaud and Dr de Lorgeril, reply follows.-ED. L. SIR,-Riitta Korpela and Tuula Vesa correctly emphasise that the consumption of dairy fat in Finland and in Scandinavian countries is lower than the data reported in figure 1 of our paper. In fact, the consumption of dairy fat is lower for all countries than the values shown. We reported the energy supplied by dairy products and not the energy supplied by dairy fat. The captions and legends of figures 1 and 2 were incorrect in this respect, for which we apologise. Nevertheless, when the relation between energy from dairy fat and mortality due to coronary heart disease is examined, the correlation coefficient is r=067, compared with )-=0’73 for dairy products. Moreover, the multivariate analysis including wine shows the same correlation coefficient (r=0-87) with either dairy fat or dairy products. whose
INSERM, Unit 63, 69500 Bron, France
SERGE RENAUD MICHEL DE LORGERIL
The limitation of GTS is its reduced consistency to detect cases with very low parasite densities. However, GTS still serves as a useful standard because false positivity by GTS (given that a gold standard existed) can reasonably be assumed to be negligible with expert reading. This implies that if QBC is definitely more sensitive than GTS, a sensitivity of 100% should always be attained, independent of parasite density. When positive specimens are predominantly of low (as opposed to high) parasitaemia, QBC sensitivity is known to become lower and is often accompanied by so-called false positivity. False positivity by QBC should be interpreted along with its sensitivity. A review of the data in study 6 showed, for the corresponding sensitivity value reported, 4 false positives by QBC that were later confirmed to be true positives (table). This is equal to the number of positives by GTS alone (19—15=4). It is therefore more sensible to conclude that, despite its relatively low sensitivity (with reference to GTS, 789%), QBC is capable of detecting as many malaria cases as is GTS. If the trade-off between cases detected by one technique but not by the other is acceptable, QBC may be thought of as being as sensitive as GTS in this instance. Similarly, QBC is slightly more sensitive in study 4 (8 vs 188 - 182 6) and slightly less sensitive in study 5B (2 vs =
100-96=4). In general we are satisfied with the overall sensitivity of QBC in the field. It is the limitation in species differentiation (4, 5A, 6) that is of concern.
haemophilia itself or its treatment with concentrates would have to be considered. We have had experience with pasteurised factor VIII concentrates from Behringwerke (Factor VIII HS/Haemate HS and Beriate HS) since 1979. We have seen 27 haemophiliacs, all under 15 years, who have been treated exclusively with these preparations and have never received blood or other blood products. All these patients are anti-HIV-negative and none of them has so far demonstrated hepatitis C positivity. All 27 patients have been vaccinated against hepatitis B. Only larger prospective infection studies involving, for comparison, a control group of corresponding age that has not been treated with blood or blood derivatives can, in our opinion, quantify the very low residual risk of therapy-induced hepatitis transmission that may still exist. Observations of isolated cases should not be overevaluated. Department of Paediatrics, University of Munster, D-4400 Munster, Germany
H. POLLMANN
H. JÜRGENS
1. Takahashi M, Yamada G, Tsuji T. Intrafamilial transmission of hepatitis C. Gastroenterol Jpn 1991; 26: 483-88. 2. Velazquez O, Stetler HC, Avila C, et al. Epidemic transmission of enterically transmitted non-A, non-B hepatitis in Mexico, 1986-1987. JAMA 1990, 263: 3281-85. 3. Mele A, Rosmini F, Zampieri A, Gill ON. Integrated epidemiological system for acute viral hepatitis in Italy (SEIEVA): description and preliminary results Eur J Epidemiol 1986; 2: 300-04.
Department of Immunology and Parasitology, Armed Forces Research Institute of Medical Sciences, Bangkok 10400, Thailand
Dairy fat intake in Finland CHANSUDA WONGSRICHANALAI
Department of Internal Medicine, Pra Pokklao Provincial Hospital,
VITHAYAT NAMSIRIPONGPUN
Chanthaburi of
Department Biochemistry, Royal Thai Army Medical School, Pra Mongkutklao Army Hospital, Bangkok
JATURAPORN PORNSILAPATIP
Department of Immunology and Parasitology, Armed Forces Research Institute of Medical Sciences
DENNIS E. KYLE
Queen Saovabha Memorial Institute, Thai Red Cross Society,
HENRY WILDE
Bangkok
G, Martet G, et al. Quantitative buffy coat (QBC test), monofluo kit falciparum: comparative value in the rapid diagnosis of malaria. Mèd Trop 1990; 50: 97-101. 2. Pornsilapatip J, Namsiripongpun V, Wilde H, Hanvanich M, Chutivongse S. Detection of plasmodia m acridine orange stained capillary tubes (the QBC system). SE Asian J Trop Med Publ Health 1990; 21: 534-40. 3 Namsiripongpun V, Pansamdaeng P, Boonyawantana V, Pomsmlapatip J, Wilde H. The acridine orange stained capillary tubes (the QBC system) in diagnosis of malaria, a field trial. J Prapokklao Hosp Clin Med Educ Center (Chanthaburi, Thailand) 1990; 7: 78-83. 4. Wongsrichanalai C, Chuanak N, Webster HK, Prasittisuk M. Accuracy and practical use of acridine orange fluorescent microscopy of centrifuged blood (QBC malaria test) in patients attending malaria clinics in Thailand. SE Asian J Trop Med Publ Health (in press). 5 Rickman LS, Long GW, Oberst R, et al. Rapid diagnosis of malaria by acridine orange staining of centrifuged parasites. Lancet 1989; i 68-71. 6. Wongsrichanalai C, Pornsilapatip J, Namsiripongpun V, et al Acridine orange fluorescent microscopy and the detection of malaria in low density parasitemia. Am J Trop Med Hyg 1991; 44: 17-20. 1. Parzy D, Raphenon
Transmission of hepatitis in haemophiliacs SIR,-Dr Schulman and colleagues (Aug 1, p 305) describe a case of hepatitis C virus (HCV) transmission after the patient had received a pasteurised factor VIII product. In our view such descriptions of isolated cases do little to elucidate the often discussed residual risk of transmission after replacement of the virusinactivated factor concentrates. We fear that both the doctor and the patient will be put into a state of uncertainty by isolated retrospective observations. Isolated observations of HCV infection in haemophilic patients are to be expected since this infection is not exclusively associated with the transmission of blood or blood derivatives.1-3 If no further cases of hepatitis infection in
haemophiliacs
were
to
occur,
protection against hepatitis by
SIR,-Dr Renaud and Dr de Lorgeril (June 20, p 1523) present data on the consumption of dairy fat in 17 OECD (Organisation for Economic Cooperation and Development) countries and compared dairy fat intake with mortality from coronary heart disease. In their fig 1 the intake of dairy fat in Finland is much greater than we calculated from OECD food consumption statistics.’ According to the OECD report’ the average dairy fat consumption (including fat from milk and milk products, cheese, butter, and buttervegetable oil mixtures) in Finland in 1980-85 was 54 g daily which yields 484 kcal. The national food balance sheets of 1980-852 indicate an average intake of 58 g daily dairy fat in Finland, yielding 525 kcal. Renaud and de Lorgeril suggest over 800 cal (we assume that this means kcal) for Finland. The intake of dairy fat in the other Nordic countries also seems to be too high in Renaud and de Lorgeril’s study according to a recent Nordic conference (Nordic Dairy Congress, Odense, Denmark, June 15-18,1992) and to our calculations based on OECD statistics. Valio Reseach and Development Centre, PO Box 390, 00101 Helsinki, Finland
RIITTA KORPELA TUULA VESA
Economic Co-operation and Development. Food consumption 1979-1988 Paris: Publications Service, 1991. 2. Agricultural price indices, total calculations, total margins for farm products, and balance sheets for food 1980-1986 Helsinki. VAPK Kampin VALTIMO, 1988. 1
Organization for statistics
***This letter has been shown to Dr Renaud and Dr de Lorgeril, reply follows.-ED. L. SIR,-Riitta Korpela and Tuula Vesa correctly emphasise that the consumption of dairy fat in Finland and in Scandinavian countries is lower than the data reported in figure 1 of our paper. In fact, the consumption of dairy fat is lower for all countries than the values shown. We reported the energy supplied by dairy products and not the energy supplied by dairy fat. The captions and legends of figures 1 and 2 were incorrect in this respect, for which we apologise. Nevertheless, when the relation between energy from dairy fat and mortality due to coronary heart disease is examined, the correlation coefficient is r=067, compared with )-=0’73 for dairy products. Moreover, the multivariate analysis including wine shows the same correlation coefficient (r=0-87) with either dairy fat or dairy products. whose
INSERM, Unit 63, 69500 Bron, France
SERGE RENAUD MICHEL DE LORGERIL
