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Smallpox eradication
®
®
' ? ) ~~ N~ . ~.~;;Ib
Voi. 3, No. t2 Copyright ~4, 1981 by G. K. Hall & Co,
June 15~ 198
[SSN 0i96-4399
Smallpex Eradieatieri
Murray D. Batt, M.D. Clinical Associa!e Professor o f Medicine and Preventive Medicir~e Section Direclor, dnfectious Disease a~:d Epidemiology Luthera,~ Genera! d-Iospita! Parle Ridge, i-I/inoi~ 60068
Introduction In May 1980, the World Health Organization (WHO) General Assemb!y certified that naturat smailpox disease had been eradicated from this planet (13). This pronouncement culminated an international effort -using a biologic product developed in the late eighteenth century and a strategy that was worked out in the mid-1960s (4). In 1966, when W H O made its Declaration o f Intent to eradicate smallpox within 10 years, 43 countries were still reporting smallpox cases, and there was indigenous transmission or endemicity (as opposed to imported cases) in 28 countries (13). Despite wars that occurred in Nigeria, Bangladesh, Ethiopia, and Soma!in during the following decade, the W H O program proceeded remarkably on schedule. West Africa became smallpox-free in 1970. The indian subcontinent (and all of Asia) was reported free of smallpox for the first time in 1975 (2). East Aft'ca had its last naturally transmitted case in 1977 (t 1). The last reported cases of smailpox in the world occurred in 1978 as a resu!t of a laboratory accident in the United Kingdom (I) and do not alter the fact that naturai transmission of smallpox had been eradicated previously. Figure 1 illustrates an electron micrograph o f variola virus in a specimen from the world's last endemic smallpox case.
-
% Fig. 1. Vc:riola mino~ virus isolete from worM's !ast endemic case, Merh'G Somelia, 1977. X dl 5,000 magnification.
The Sma[Ii~ox Proolem By raid-1960, endemic smallpox was restricted to the developing world, but importations of smallpox were not uncommon in Europe and were expected in the United States. The ciinicai aspects of the disease are illustrated by Figures 2 and 3 (!0). Morbidity included permanent blindness, and there was a mortality rate o f 2507o for variola major and 1% for variola minor. By 1965, the United States was spending an estimated $140 million per year on i:s program to keep out smatlpox (5). in I968, approximately 14 million Americans were immunized against smallpox. There were 572 confirmed vaccination compI:.cations inciud'ng postvaccinai encephalitis, vaccinia necrosum, eczema vaccinatum, and generalized vaccinia. Nine patients died, directly because of smallpox vaccination (8). During January I970, 20 cases o f smallpox occurred in the Meschede Hospital in Germany, graphica!ly illustrating the smallpox risk for
developed countries. The index case was a patient who had just returned from West Pakistan (6). An elegant investigation of the outbreak illustrated :he airborne mechanism of disease dissemination (i4).
Methods of Smallpox Eradication After the Centers for Disease Control (CDC) became involved with the United States Agency for international Development (USAID) in West Africa, smallpox eradication was taken up by WHO. The CDC effort invoived hundreds of CDC physicians and thousands o f other persons who contributed to the successful outcome of these programs. The methods used included " r i n g " vaccination of people living around areas where outbreaks had occurred, as opposed to the prior method of mass vaccination, and intensified surveillance, looking for outbreaks of disease rather than just counting cases. As a given country came nearer to the goal of eradication, the number of reported cases usually rose because of improved surveiliance. In india, a reward system was :.sod successfuily to obtain reports of cases. Within a 10-mile radius of a case, house-tohouse searches might be required, and the intervai between occurrence o f a
tri This fssue Smallpox Eradication . . .
77
Blood Culture Survey Response (Part I) . . .
80
Letters . . .
84
Workshops and Meetings . . .
84
case and institution of a local vaccination program decreased (4).
Smallpox Investigation
Fig. 2.
In 1970, as an Epidemic Intelligent., Service Officer for the CDC assist" the Nigerian Red Cross Relief Acti in the Nigerian Civil War, I had t!:~. opportunity to participate in the investigation of one of the last cases of smallpox that occurred in West Africa. To illustrate the surveillance method used, I will describe an investigation I conducted in Nigeria April 22-23, 1970 (3). I was asked to investigate an alleged case of smallpox said to have occurred within the last few weeks near Idah, Kwara State. On March 16, 1970, the rural health assistant had been notified of a smallpox case that had occurred in a local village (Ojuwo) on March 10, 1970, and he had investigated at once. I drove out to Ojuwo with the rural health assistant, and we located the patient without great difficulty. He had been visiting a native doctor in search of medicines to restore sight that had been lost in his right eye during his recent illness. The patient was living in an isolation hut where the villagers had put him even before smallpox program personnel were notified.
Child with characteristic lesions (pocks) of snzallpox.
DAYS OF RASH
RASH MACULES THE
FEVER A N D S T A G E S
OF D E V E L O P M E N T THE
RASH
PAPULES
OF
IN A T Y P I C A L
SMALLPOX
Fig. 3.
I
CASE
Graph ilhtstrating clinical course of smallpox.
I VESICLES
I
For four days preceding March I0, the patient had suffered fever with pains all over his body, including his bones and even his teeth. The rash began on his face, especially around his eyes, and on his chest. Within two days, it had spread to his palms, soles, back, and legs. No additional lesions erupted. The patient was a hunter and farmer. Aside from his hunting travels, he recalled a single trip, one week before his fever began, to Ejule Market, about 13 miles from his home in another district. He traveled by either foot or bicycle and was unaware of any contact with a case of smallpox. By April 23 the patient essentially had recovered. He had neither a history of vaccination nor a vaccination scar. Skin was still peeling from the soles of his feet, and there were a few pink areas on his extremities, apparently where scabs had recently fallen off. His right cornea was completely opaque and partially eroded. The rural health assistant had seen the patient when his rash was full-blown and described the Iesions as being extensive on the forearms, palms, and soles, but almost sparing the face, chest, lower lumbar area, and dorsa of the feet. The patient was photographed, and serum was obtained. He produced some old scabs from a hiding place and was warned to destroy any he was still hiding. On March 16, 350 villagers in Ojuwo were vaccinated by multiple pressure technique and then revaccinated a week later by jet gun. Of 37 villagers inspected on April 23, 25 had scar evidence of old vaccination, and 34 had evidence of recent vaccination. There were no individuals who had neither an old nor a recent scar. Notably, the patient's wife had no old scar, and she was successfully vaccinated on March 16. Although the population of Ojuwo Village is said to be almost 500, most of those seen on April 23 were women and children. The men were said to be at their farms. No secondary cases of smallpox are known to have occurred from this index patient. Two additional cases
from a nearby district were confirmed in January 1970, but the source of our patient's smallpox remains obscure. Results of Smallpox Eradication The total estimated cost of the 10-year WHO program to eradicate smallpox involved no more than $24 million, only a portion of which was funded by the United States (5). In the late 1960s and early 1970s, routine smallpox immunization of children was discontinued in the United States. The program to vaccinate all health workers (never a resounding success) has been discontinued. A few countries and many travel agents have not yet ceased to recommend smallpox immunization for travelers. At the present time, the vaccine is not manufactured in the United States and is obtainable only with difficulty, if at all. Considering the greater risk than benefit ratio now prevailing, physicians would not be incorrect in writing "vaccination contraindicated" on the Certificate for International Travel. There is no benefit in immunizing against a disease that has been eradicated. The risk of vaccination has been defined (12). A side benefit of the unavailability of smallpox vaccine is the disappearance of the medically dubious practice of "therapeutic" application of smallpox vaccine (never shown to be efficacious, and too often associated with morbidity). Smallpox vaccination requirements are disappearing rapidly. Stocks of smallpox virus are being destroyed or sent to a small number of WHO collaborating centers where extraordinary security can be maintained while further research on pox viruses is done and a reference agent kept available. Lessons Learned from Smallpox Eradication What lessons does the eradication of smallpox hold for future international disease containment programs? Perhaps the major result was the historic precedent set whereby developing and developed countries served their own national interests by cooperating to control this disease.
The difficulties of famine, war, and massive population shifts in Nigeria (during its civil war), in Bangladesh, and in the horn of Africa cannot be minimized, but they did not prevent the ultimate eradication of smallpox in each of these areas. Nevertheless, other disease problems should not be analogized too closely to smallpox. There were many unique features in this program, all of which may never apply to another public health campaign. a) Smallpox was such a highly conspicuous disease that nonmedical people could easily be enlisted to assist in surveillance. b) The fear of the illness allowed stringent public health measures to be employed. c) In tropical climates where the disease was endemic, transmission did not generally occur as explosively as in the now classic Meschede Hospital outbreak in West Germany. d) There were no chronic human carriers of smallpox, nor has an animal reservoir been discovered. e) The lyophilized smalIpox vaccine retained its efficacy and did not require cold shipment to maintain its biologic potency. 0 The smallpox vaccination left a permanent mark, avoiding the need for duplicate immunizations. g) Developed as well as developing coufltries had a vested interest in eradication of this disease. Perhaps the final conclusion could be that, although famines and wars did not prevent smallpox eradication, there is little doubt that the program would have succeeded sooner if these massive civil disturbances had not occurred. To the morbidity and mortality o f each of the abovementioned wars has to be added the prolongation of endemic smallpox, which now, barring reintroduction in the form of accident or biologic warfare, fortunately is of historic interest only.
References 1. Allman, L. K. 1979. The eradication of smallpox. The New York Times, October 16, 1979, p. C3.
2. Asia is reported free of smallpox for the first time in history. 1975. The New York Times, November 14, I975, p. C3. 3. Batt, M. D. 1970. Smallpox investigation, Kwara state. April 22-23, 1970. Unpublished report to Smallpox Eradication Program. 4. Centers for Disease Control. N.d. National program for the vaccination of hospital workers against smallpox. Centers for Disease Control, Atlanta. 5. Centers for Disease Control. 1972. Vaccination against smallpox in the United States. A re-evaluation of the risks and benefits. DHEW (HSM)728104.
6. Foege, W. II. 1975. Global smallpox eradication. Paper presented at 24th Annual Epidemic Intelligence Service Conference, Atlanta, April 21. 7. Foege, W. H. 1975. Smallpox eradication. Paper presented at Medical Seminar, Division of Medicine, Lutheran General Hospital, Park Ridge, I11., May 16. 8. Follow-up smallpox--Federal Republic of Germany. 1970. Morbid. Mortal. Weekly Rep. 19:234-240. 9. Health information for international travel. 1980. Morbid. Mortal. Weekly Rep. 29:Supplement (June, 1980). 10. Lane, J. M., et al. 1969. Complications of smallpox vaccination, 1968.
N. Engl. J. Med. 281:1201-1208. 11. Smallpox Certification--East Africa. 1979. Morbid. Mortal. Weekly Rep. 28:497-499. 12. Wehrle, P. F. 1980. A reality in our time--certification of the global eradication of smallpox. J. Infect. Dis. 142:636-668. 13. Wehrle, P. F., el al. 1970. An airborne outbreak of smallpox in a German hospital and its significance with respect to other recent outbreaks in Europe. Bull. WHO 43:669-679. 14. World tlealth Organization. N.d. Smallpox, a pictorial guide to diagnosis. WHO Regional Office for Africa, Geneva, Switzerland.
Results of the Survey of Blood Culture Methods (Part 1) Response to the blood culture questionnaire (vol. 3, no. 4) was excellent, topping all our previous surveys with responses from 341 laboratories. Since some o f the questions required long and detailed answers, we have decided to present the results o f the survey in two issues. The results printed here include those that have to do with actual methods of culturing the blood and detecting positive cultures. (Readers will note changes in the numbering of some survey questions.) In the next issue o f the Newsletter, we will present the data pertaining to subculture o f positive blood cultures and rapid tests used for identification o f organisms. In s u m m a r y , the results here show that most laboratories use a soybean casein digest broth in 30-50 ml amounts and a 1: 10 dilution o f blood to broth. The great majority of laboratories incubate blood cultures for seven days, with extended incubation if brucellosis is suspected. A b o u t half the laboratories extend incubation if endocarditis is the diagnosis. H a l f o f the laboratories perform blind G r a m stains, and almost all laboratories perform blind subcultures on one or more days. As in previous surveys, there was a wide variety in charges; the cost of a blood culture varied from $6.50 to $65.
1. Type o f laboratory 322 3 13 3
Hospital Clinic Private Other: Public Health; Regional
3. If hospital laboratory, how m a n y beds? 62 167 67 26
<7 200 200-499 500-800 > 800
2. If hospital laboratory, specify type 224 22 58 21
Community VA or other government hospital Medical school or affiliate Other
4. N u m b e r o f blood cultures done per year (Include only specimens sent for bacteriology culture.) 102 118 60 44
. ( 2,000 2,000-5,000 5,000-10,000 > 10,000
5. Who collects blood samples for culture? 100 Physicians 41 Nurses 11 IV team 206 Venipuncture team 54 Microbiology technologists 135 Clinical laboratory technologists (Includes multiple answers f r o m individual respondents.)
6. What is used to disinfect the venipuncture site? 22 14 140 19 184 1
Isopropyl alcohol Ethanol Povidone iodine (e.g., Betadine) Tincture o f iodine Multiples of above in series Chlorhexidine/ethanol
®
' ? ) ~~ N~ . ~.~;;Ib
Voi. 3, No. t2 Copyright ~4, 1981 by G. K. Hall & Co,
June 15~ 198
[SSN 0i96-4399
Smallpex Eradieatieri
Murray D. Batt, M.D. Clinical Associa!e Professor o f Medicine and Preventive Medicir~e Section Direclor, dnfectious Disease a~:d Epidemiology Luthera,~ Genera! d-Iospita! Parle Ridge, i-I/inoi~ 60068
Introduction In May 1980, the World Health Organization (WHO) General Assemb!y certified that naturat smailpox disease had been eradicated from this planet (13). This pronouncement culminated an international effort -using a biologic product developed in the late eighteenth century and a strategy that was worked out in the mid-1960s (4). In 1966, when W H O made its Declaration o f Intent to eradicate smallpox within 10 years, 43 countries were still reporting smallpox cases, and there was indigenous transmission or endemicity (as opposed to imported cases) in 28 countries (13). Despite wars that occurred in Nigeria, Bangladesh, Ethiopia, and Soma!in during the following decade, the W H O program proceeded remarkably on schedule. West Africa became smallpox-free in 1970. The indian subcontinent (and all of Asia) was reported free of smallpox for the first time in 1975 (2). East Aft'ca had its last naturally transmitted case in 1977 (t 1). The last reported cases of smailpox in the world occurred in 1978 as a resu!t of a laboratory accident in the United Kingdom (I) and do not alter the fact that naturai transmission of smallpox had been eradicated previously. Figure 1 illustrates an electron micrograph o f variola virus in a specimen from the world's last endemic smallpox case.
-
% Fig. 1. Vc:riola mino~ virus isolete from worM's !ast endemic case, Merh'G Somelia, 1977. X dl 5,000 magnification.
The Sma[Ii~ox Proolem By raid-1960, endemic smallpox was restricted to the developing world, but importations of smallpox were not uncommon in Europe and were expected in the United States. The ciinicai aspects of the disease are illustrated by Figures 2 and 3 (!0). Morbidity included permanent blindness, and there was a mortality rate o f 2507o for variola major and 1% for variola minor. By 1965, the United States was spending an estimated $140 million per year on i:s program to keep out smatlpox (5). in I968, approximately 14 million Americans were immunized against smallpox. There were 572 confirmed vaccination compI:.cations inciud'ng postvaccinai encephalitis, vaccinia necrosum, eczema vaccinatum, and generalized vaccinia. Nine patients died, directly because of smallpox vaccination (8). During January I970, 20 cases o f smallpox occurred in the Meschede Hospital in Germany, graphica!ly illustrating the smallpox risk for
developed countries. The index case was a patient who had just returned from West Pakistan (6). An elegant investigation of the outbreak illustrated :he airborne mechanism of disease dissemination (i4).
Methods of Smallpox Eradication After the Centers for Disease Control (CDC) became involved with the United States Agency for international Development (USAID) in West Africa, smallpox eradication was taken up by WHO. The CDC effort invoived hundreds of CDC physicians and thousands o f other persons who contributed to the successful outcome of these programs. The methods used included " r i n g " vaccination of people living around areas where outbreaks had occurred, as opposed to the prior method of mass vaccination, and intensified surveillance, looking for outbreaks of disease rather than just counting cases. As a given country came nearer to the goal of eradication, the number of reported cases usually rose because of improved surveiliance. In india, a reward system was :.sod successfuily to obtain reports of cases. Within a 10-mile radius of a case, house-tohouse searches might be required, and the intervai between occurrence o f a
tri This fssue Smallpox Eradication . . .
77
Blood Culture Survey Response (Part I) . . .
80
Letters . . .
84
Workshops and Meetings . . .
84
case and institution of a local vaccination program decreased (4).
Smallpox Investigation
Fig. 2.
In 1970, as an Epidemic Intelligent., Service Officer for the CDC assist" the Nigerian Red Cross Relief Acti in the Nigerian Civil War, I had t!:~. opportunity to participate in the investigation of one of the last cases of smallpox that occurred in West Africa. To illustrate the surveillance method used, I will describe an investigation I conducted in Nigeria April 22-23, 1970 (3). I was asked to investigate an alleged case of smallpox said to have occurred within the last few weeks near Idah, Kwara State. On March 16, 1970, the rural health assistant had been notified of a smallpox case that had occurred in a local village (Ojuwo) on March 10, 1970, and he had investigated at once. I drove out to Ojuwo with the rural health assistant, and we located the patient without great difficulty. He had been visiting a native doctor in search of medicines to restore sight that had been lost in his right eye during his recent illness. The patient was living in an isolation hut where the villagers had put him even before smallpox program personnel were notified.
Child with characteristic lesions (pocks) of snzallpox.
DAYS OF RASH
RASH MACULES THE
FEVER A N D S T A G E S
OF D E V E L O P M E N T THE
RASH
PAPULES
OF
IN A T Y P I C A L
SMALLPOX
Fig. 3.
I
CASE
Graph ilhtstrating clinical course of smallpox.
I VESICLES
I
For four days preceding March I0, the patient had suffered fever with pains all over his body, including his bones and even his teeth. The rash began on his face, especially around his eyes, and on his chest. Within two days, it had spread to his palms, soles, back, and legs. No additional lesions erupted. The patient was a hunter and farmer. Aside from his hunting travels, he recalled a single trip, one week before his fever began, to Ejule Market, about 13 miles from his home in another district. He traveled by either foot or bicycle and was unaware of any contact with a case of smallpox. By April 23 the patient essentially had recovered. He had neither a history of vaccination nor a vaccination scar. Skin was still peeling from the soles of his feet, and there were a few pink areas on his extremities, apparently where scabs had recently fallen off. His right cornea was completely opaque and partially eroded. The rural health assistant had seen the patient when his rash was full-blown and described the Iesions as being extensive on the forearms, palms, and soles, but almost sparing the face, chest, lower lumbar area, and dorsa of the feet. The patient was photographed, and serum was obtained. He produced some old scabs from a hiding place and was warned to destroy any he was still hiding. On March 16, 350 villagers in Ojuwo were vaccinated by multiple pressure technique and then revaccinated a week later by jet gun. Of 37 villagers inspected on April 23, 25 had scar evidence of old vaccination, and 34 had evidence of recent vaccination. There were no individuals who had neither an old nor a recent scar. Notably, the patient's wife had no old scar, and she was successfully vaccinated on March 16. Although the population of Ojuwo Village is said to be almost 500, most of those seen on April 23 were women and children. The men were said to be at their farms. No secondary cases of smallpox are known to have occurred from this index patient. Two additional cases
from a nearby district were confirmed in January 1970, but the source of our patient's smallpox remains obscure. Results of Smallpox Eradication The total estimated cost of the 10-year WHO program to eradicate smallpox involved no more than $24 million, only a portion of which was funded by the United States (5). In the late 1960s and early 1970s, routine smallpox immunization of children was discontinued in the United States. The program to vaccinate all health workers (never a resounding success) has been discontinued. A few countries and many travel agents have not yet ceased to recommend smallpox immunization for travelers. At the present time, the vaccine is not manufactured in the United States and is obtainable only with difficulty, if at all. Considering the greater risk than benefit ratio now prevailing, physicians would not be incorrect in writing "vaccination contraindicated" on the Certificate for International Travel. There is no benefit in immunizing against a disease that has been eradicated. The risk of vaccination has been defined (12). A side benefit of the unavailability of smallpox vaccine is the disappearance of the medically dubious practice of "therapeutic" application of smallpox vaccine (never shown to be efficacious, and too often associated with morbidity). Smallpox vaccination requirements are disappearing rapidly. Stocks of smallpox virus are being destroyed or sent to a small number of WHO collaborating centers where extraordinary security can be maintained while further research on pox viruses is done and a reference agent kept available. Lessons Learned from Smallpox Eradication What lessons does the eradication of smallpox hold for future international disease containment programs? Perhaps the major result was the historic precedent set whereby developing and developed countries served their own national interests by cooperating to control this disease.
The difficulties of famine, war, and massive population shifts in Nigeria (during its civil war), in Bangladesh, and in the horn of Africa cannot be minimized, but they did not prevent the ultimate eradication of smallpox in each of these areas. Nevertheless, other disease problems should not be analogized too closely to smallpox. There were many unique features in this program, all of which may never apply to another public health campaign. a) Smallpox was such a highly conspicuous disease that nonmedical people could easily be enlisted to assist in surveillance. b) The fear of the illness allowed stringent public health measures to be employed. c) In tropical climates where the disease was endemic, transmission did not generally occur as explosively as in the now classic Meschede Hospital outbreak in West Germany. d) There were no chronic human carriers of smallpox, nor has an animal reservoir been discovered. e) The lyophilized smalIpox vaccine retained its efficacy and did not require cold shipment to maintain its biologic potency. 0 The smallpox vaccination left a permanent mark, avoiding the need for duplicate immunizations. g) Developed as well as developing coufltries had a vested interest in eradication of this disease. Perhaps the final conclusion could be that, although famines and wars did not prevent smallpox eradication, there is little doubt that the program would have succeeded sooner if these massive civil disturbances had not occurred. To the morbidity and mortality o f each of the abovementioned wars has to be added the prolongation of endemic smallpox, which now, barring reintroduction in the form of accident or biologic warfare, fortunately is of historic interest only.
References 1. Allman, L. K. 1979. The eradication of smallpox. The New York Times, October 16, 1979, p. C3.
2. Asia is reported free of smallpox for the first time in history. 1975. The New York Times, November 14, I975, p. C3. 3. Batt, M. D. 1970. Smallpox investigation, Kwara state. April 22-23, 1970. Unpublished report to Smallpox Eradication Program. 4. Centers for Disease Control. N.d. National program for the vaccination of hospital workers against smallpox. Centers for Disease Control, Atlanta. 5. Centers for Disease Control. 1972. Vaccination against smallpox in the United States. A re-evaluation of the risks and benefits. DHEW (HSM)728104.
6. Foege, W. II. 1975. Global smallpox eradication. Paper presented at 24th Annual Epidemic Intelligence Service Conference, Atlanta, April 21. 7. Foege, W. H. 1975. Smallpox eradication. Paper presented at Medical Seminar, Division of Medicine, Lutheran General Hospital, Park Ridge, I11., May 16. 8. Follow-up smallpox--Federal Republic of Germany. 1970. Morbid. Mortal. Weekly Rep. 19:234-240. 9. Health information for international travel. 1980. Morbid. Mortal. Weekly Rep. 29:Supplement (June, 1980). 10. Lane, J. M., et al. 1969. Complications of smallpox vaccination, 1968.
N. Engl. J. Med. 281:1201-1208. 11. Smallpox Certification--East Africa. 1979. Morbid. Mortal. Weekly Rep. 28:497-499. 12. Wehrle, P. F. 1980. A reality in our time--certification of the global eradication of smallpox. J. Infect. Dis. 142:636-668. 13. Wehrle, P. F., el al. 1970. An airborne outbreak of smallpox in a German hospital and its significance with respect to other recent outbreaks in Europe. Bull. WHO 43:669-679. 14. World tlealth Organization. N.d. Smallpox, a pictorial guide to diagnosis. WHO Regional Office for Africa, Geneva, Switzerland.
Results of the Survey of Blood Culture Methods (Part 1) Response to the blood culture questionnaire (vol. 3, no. 4) was excellent, topping all our previous surveys with responses from 341 laboratories. Since some o f the questions required long and detailed answers, we have decided to present the results o f the survey in two issues. The results printed here include those that have to do with actual methods of culturing the blood and detecting positive cultures. (Readers will note changes in the numbering of some survey questions.) In the next issue o f the Newsletter, we will present the data pertaining to subculture o f positive blood cultures and rapid tests used for identification o f organisms. In s u m m a r y , the results here show that most laboratories use a soybean casein digest broth in 30-50 ml amounts and a 1: 10 dilution o f blood to broth. The great majority of laboratories incubate blood cultures for seven days, with extended incubation if brucellosis is suspected. A b o u t half the laboratories extend incubation if endocarditis is the diagnosis. H a l f o f the laboratories perform blind G r a m stains, and almost all laboratories perform blind subcultures on one or more days. As in previous surveys, there was a wide variety in charges; the cost of a blood culture varied from $6.50 to $65.
1. Type o f laboratory 322 3 13 3
Hospital Clinic Private Other: Public Health; Regional
3. If hospital laboratory, how m a n y beds? 62 167 67 26
<7 200 200-499 500-800 > 800
2. If hospital laboratory, specify type 224 22 58 21
Community VA or other government hospital Medical school or affiliate Other
4. N u m b e r o f blood cultures done per year (Include only specimens sent for bacteriology culture.) 102 118 60 44
. ( 2,000 2,000-5,000 5,000-10,000 > 10,000
5. Who collects blood samples for culture? 100 Physicians 41 Nurses 11 IV team 206 Venipuncture team 54 Microbiology technologists 135 Clinical laboratory technologists (Includes multiple answers f r o m individual respondents.)
6. What is used to disinfect the venipuncture site? 22 14 140 19 184 1
Isopropyl alcohol Ethanol Povidone iodine (e.g., Betadine) Tincture o f iodine Multiples of above in series Chlorhexidine/ethanol