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Tropical Doctor, January 1991

REFERENCES

1 Drummond KN. Infection of the urinary tract. In: Vaughan VC, Mckay RJ, Behrman RE, eds. Nelson textbook of paediatrics. Philadelphia: W B Saunders, 1979:1543-8 2 Kass EH. Asymptomatic infections of the urinary tract. Trans Assoc Am J 1956;69:56-63 3 Pryles CV, Eliot CR. Pyuria and bacteriuria in infants and children. Am J Dis Child 1965;110:628-39 4 Wilson JR, Schloss OM. Pathology of so called "acute pyelitis" in infants. Am J Dis Child 1929;38:227 5 Aleinacychu A, MesslesG. Pyuria and significant bacteriuria in urinary tract infections. Ethiop Med J 1981;19:135 6 Smith RM. Urinary infection in children. New Engl J Med 1931;205:181 7 Hellerstein S. Diagnosis of infections of the urinary tract. In urinary tract infections in children. Chicago: Year Book Medical Publishers, 1982:10-12

Occupational HIV infection and health care workers in the tropics Hans Veeken

MD Tropical Medicine and Hygiene, Royal Tropical Institute (KIT), Amsterdam los Verbeek MD Research-Group Work and Health, Faculty of Medicine, University of Amsterdam Hans Houweling MD DiplEpid Department ofEpidemiology, National Institute ofPublic Health and Environmental Protection (RIVM), Bilthoven Frank Cobelens MD Bureau ofthe National Committee for AIDS Control (NCAB), Amsterdam TROPICAL DOCTOR,

1991, 21, 28-31

A literature reviewrevealed 33 reports of health care workers who have contracted HIV infection as a result of their work. Four of these were expatriate doctors who had worked in Africa. The commonest mode of transmission was needlestick injury, but several infections acquired through contact or skin or mucous membrane with infected blood have been reported. Correspondence to: Hans Veeken MD, Wilhelminastraat 180", 1054 WT Amsterdam, The Netherlands

8 Savage DCL, Wilson MI, Mclardy M. Covert bacteriuria in childhood: a clinical and epidemiological study. Arch Dis Child 1973;48:8-19 9 Kunin CM, Southall I, Paqurn AJ. Epidemiology of urinary tract infection: A pilod study of 3057 school children. New Engl J Med 1960;263:817 10 Abdurrahman MB, Chakrabarty DP and Ochoga SA (1978) Bacteriuria and other urinary abnormalities among primary school children in Kaduna. Nig J Paed 1978;5:21-4 11 Gelfand M. Schistosomiasis. In: Jellfe DB, Stanfield JP, eds. Diseases of children in the subtropics and tropics, 3rd edn. 1981:897-8 12 Stansfiled JM, Webb JK. Observation in pyuria in children. Arch Dis Child 1953;28:386-7 13 Hart AF, Cherry JD. Cytology of the urine in children after oral poliovirus vaccine. New Engl J Med 1965;272: 174-7

In this paper we outline how the risk of HIV infection in a health care worker can be estimated for a given number of exposures. The formula is based on the known likelihood of transmission per needlestick, the seroprevalence rate among patients, and the number of needlestick injuries that occur. We also suggest a list of measures by which the risk of HIV transmission to hospital staff can be minimized. INTRODUCTION

It is estimated that 5 million people are already

infected with the human immunodeficiency virus (HIV)I. Health care workers (HCW) providing care for HIV -infected patients are at risk of occupational infection. In many tropical countries the seroprevalence of HIV is known to be high. The incidence of needlestick injuries in HCW working in the tropics is probably higher than in most Western countries. In this paper we reviewpublished data on the risk of occupational HIV infection in HCW and formulate guidelines to reduce the risk of transmission. METHODS

We reviewed the literature for published data on HIV transmission to HCWs, using Index Medicus '89 and Medline '89. We collected information on the following subjects: the number of reported HIV infections in HCWs, modes of transmission, risk of seroconversion, and incidence of needlestick injuries.

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Tropical Doctor, January 1991 Table 1. Number of HeW with occupationallyacquired HIV infection in different categories Documented: percutaneous transmission non-intact skin/mucous membrane Presumptive: occupational transmission

15 4 15

Total

34

visibly contaminated with blood? Nearly all cases of occupational HIV-infection among HCW, however, were due to exposure to blood known to be contaminated with HIV8. In one of the reported 33 cases infection occurred after exposure to bloodstained pleural fluid". The most common mechanism of transmission in the health care setting is percutaneous inoculation of blood from a HIVinfected patient through a needlestick!".

INCIDENCE OF OCCUPATIONAL INFECTION IN HCWs

INCIDENCE OF NEEDLESTICK INJURIES

Gill and Porter listed all 19 documented seroconversions in HCW that have been reported up to February 19892 (Table 1). Seroconversion or infection is considered 'documented' when the HIV infection in the source patient is established, and seroconversion after a registered incident is documented, a serum sample having been tested for HIV serology either before or immediately after the incident. Fifteen of these documented infections had been caused by percutaneous inoculation. The remaining four had been caused by means of exposure of non-intact skin or mucous membranes, or both, to blood from an HIV -infected source patient. In addition to the above mentioned group of 19 documented seroconversions, Gill and Porter reported another group of 13 presumptive seroconversions. In this group nobody had any of the established non-occupational risk factors. All sustained exposure to blood of patients, but either the HIV infection in the patient or the seroconversion in the HCW after the incident was not documented properly. Apart from those reported by Gill and Porter, two more HCW, both doctors, had a presumptive diagnosis of occupationally acquired HIV infection- (and H Houweling, unpublished data). One of them was self-reported", All doctors fall into the category of presumptive infection; four out of the six doctors had been working in Africav" (and Houweling, unpublished data).

Accidental needlestick injuries while operating are inevitable. Injuries occur in 1.5-5.6010 of operations'I-P. In a Western style hospital in Saudi Arabia, Hussain found a correlation between the number of injuries and the experience of the surgeon--. Consultants sustained injuries in 4% of all procedures, compared with 12% for assistant surgeons. In a study in Dutch hospitals an incidence of 7.7 needlesticks a year for every hundred hospital workers from all departments has been reported 13. For theatre personnel an incidence of 1.5 exposures/ year for every member of the operating team was found!'. The only figure available for African working circumstances gives a mean of 9.1 and a median of two needlestick injuries during an average contract of 3.6 years for 406 Dutch HCW working in Africa. The range varied from 0 to 300. This group includes doctors, midwives, nurses, laboratory personnel and other (para)medics. The reported number of needlesticks varied by profession: for doctors the mean was 15.0 and median 5, for midwives the mean was 12.2 and median 5, and for nurses the mean was 3.4 and median 0 (H Houweling, unpublished data, 1990).

MODES OF TRANSMISSION

Apart from blood, HIV has been isolated from the following fluids: tissue fluid, cerebrospinal fluid, peritoneal fluid, pleural fluid, synovia, amniotic fluid, vaginal secretion, semen, breastmilk, urine, and saliva? Theoretically all these fluids can transmit the infection, either through percutaneous inoculation or via exposure of non-intact skin or mucous membranes. The US Centers for Disease Control consider urine and saliva non-infectious unless

RISK OF SEROCONVERSION AFTER NEEDLESTICK INJURY

The mean seroconversion rate following an accidental percutaneous inoculation of seropositive blood is calculated to be 0.49%2. This figure is based on follow-up of 1852 injuries with hollow injection needles contaminated with HI V-seropositive blood. In most instances the blood was from patients with symptomatic HIV-related disease. The chance of seroconversion after a superficial needlestick caused by a solid needle while operating is probably lower 14,15. Given the fact that in asymptomatic patients mean titres of antigen are about 100 times lower than in AIDS patients, the risk of transmission from operations on asymptomatic patients is likely to be less than it is from operations on patients with AIDS16.

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Tropical Doctor, January 1991

Table 2. Three-year cumulative risk per HCW according to number of needlestick injuries (see text) and HIV prevalence rates Number of needlestick injuries

HIV prevalence

1% 18070

2 (median)

9.1 (mean)

0.01 % 0.18%

0.05% 0.82%

Both anecdotal reports and prospective studies suggest that the risk of conversion after direct exposure of non-intact skin or mucous membranes to infective blood is much lower than after a needlestick, but no exact figures are available. The probability of transmission via intact skin or mucosa seems to be related to the amount of blood involved and the duration of exposure'", In prospective studies no infection via this route has been documented", The cumulative risk of seroconversion due to percutaneous injuries is related to the prevalence of the infection in the population, the number of exposures and the chance of transmission per exposure. It can be calculated with the following formula based on the binomial distribution: (1- [I - fp] "). In this formula f is the seroprevalence in the population, p the chance of transmission per incident, and n the number of incidents. In most countries of Central Africa HIV prevalence is higher than 1% I, and in some cities and groups it is above 10% 1,17. The individual risk of seroconversion can be calculated by applying the formula. For example, if we assume a risk of seroconversion per needlestick injury of 0.5% (=0.005), thenaHCWwho suffers 5 needlestick injuries, while working in a patient population of whom 10% (= 0.1) are HIV seropositive, has a risk of contracting HIV infection of 0.25% (one in 400). For the Dutch HCWs described above, with a mean of 9.1 needlestick injuries, the estimated risk varies from 0.05% (one in 2000) to 0.82% (one in 122) depending on HIV prevalence (Table 2). RECOMMENDATIONS FOR PREVENTION

(1) Prevent needlestick injuries

General • Never recap needles. One third of the needlestick injuries occur during recapping'". • Dispose of needles immediately after use. Have plenty of containers ready in places where needles are used!".

• Transport used needles only in containers'", • Sterilize used needles twice: the first time before the household cleaning procedure, in order to prevent transmission during the cleaning procedure. Theatre • Critically review the work method in theatre!". • Put emphasis on training in handling sharp instruments and safe techniques. • Sharp instruments should never be placed directly into the hands of the surgeon or assistant. Two people must not touch a sharp instrument at the same time!". • A magnetic pad, placed on the patient, could provide a neutral place between the operating field and the Mayo table, on which the scrub nurse can place the instruments for the operator!", • Pass sharp instruments only with a verbal warning and eye contact!". • Handle sharps only with other instruments!". • Store used needles in a special box on the Mayo table!". • Loaded needle carriers should lie pointdownwards!". • Sharp instruments should not project beyond the table edge!". • Store sharp retractors on a remote corner of the Mayo table!". • Coordinate movements carefully; agree beforehand who will apply compression in case of unexpected bleeding!", • Do not sponge unnecessarily-it places the hands at risk!". • Use a self-retaining retractor in order to reduce the number of people at risk. • Tissue should always be handled with instruments instead of fingers, when a sharp instrument is in the field. • Use forceps to stabilize a needle. The moment at which a needle emerges from the tissue, while not under direct vision, has been shown to be dangerous'>, • Use sharp needles; repeatedly used needles become blunt and therefore considerable force is required to manipulate them through tissue, with subsequent risk of injury. • Pay special attention while closing the abdomen. Many needlesticks occur during closure of the abdominal wall-'. Mass closure carries the greatest risk of injuries-", • Consider the introduction of sandwich gloving

Tropical Doctor, January 1991 during closure of the abdomen and during orthopaedic procedures. A sandwich glove consists of three layers: an inner latex glove, a cotton glove, and an outer latex glove. • Never place sutures and tie knots at the same time. • If a needlestick injury occurs the glove and the instrument should be removed from the field-'. (2) Prevent non-intact skin and mucous membrane contamination

• Wear gloveswhiletouching mucous membranes or non-intact skin-'. • All people who assist at a delivery should wear gloves". • Wear gloves while handling the placenta and the newborn, and during postdelivery care of the umbilicus-'. • Use long sleeved gloves while performing a manual removal of the placenta. • Have mouth pieces and ventilation bags ready in theatre and labour ward-'. • Use new gloves for major operations; resterilized gloves are more likely to rupture. Gloves should fit properly. • During a caesarean section an apron should be worn, to prevent the operator's clothing being soaked with blood. • Long rubber boots are needed to protect the feet against blood and against falling instruments. • Use spectacles during operations, especially during orthopaedic procedures-'. • A HeW with an exudative skin lesion should refrain from direct patient care". • If forced to operate with a non-intact skin, cover the lesion with water resistant tape", even though this may have an adverse effect on sterility. (3) Remember

• All patients should be considered as potentially HIV -infected. • If adequate precautions had been taken, 40070 of known needlestick injuries could have been prevented>, • Anticipate possiblecontamination, for example when performing venepuncture on an uncooperative patient. REFERENCES

Sato P, Chin J, Mann J. Review of AIDS and HIV infection: global epidemiology and statistics. AIDS 1989; 3(suppl 1):S301-7

31 2 Gill N, Porter K. Occupational transmission of HIV. Summary of published reports. London: PHLS Communicable Disease Surveillance Centre (61 Colindale Avenue London NW9 5EQ), 1989 3 Hacib Aoun. When a house officer gets AIDS. N Engl J Med 1989;321:693-6 4 Bygbjerg IC. AIDS in a Danish surgeon (Zaire, 1976). Lancet 1983;i:925 5 Bonneux L, Van der Stuyff P, Taelman H, et al. Risk factors for infection with HIV among European expatriates in Africa. BMJ 1988;297:581-7 6 Houweling H, Jager JC, Coutinho RA, et al. Epidemiologie van AIDS en HIV -infecties in Nederland; huidige situatie en prognose voor de periode 1987-1990. Ned Tijdschr Geneeskd 1987;131:818-24 7 Anonymous. Update: Universal precautions for prevention of transmission of HIV, hepatitis B and other blood borne pathogens in health care settings. MMWR 1988;37:377-82 8 Henderson D. Perspectives on the risks for occupational transmission of HIV-1 in the health centre workplace. State Art Rev Occup Med 1989;4:7-12 9 Oksenhendler E, Harzic M, Le Roux J, et al. HIV infection with seroconversion after a superficial needlestick injury to the finger. N Engl J Med 1986;315:582 10 CDC. AIDS and HIV update: AIDS and HIV infection among health care workers. MMWR 1988;37(4) 11 Leentvaar-Kuypers A, Keeman J, Dekker E, et al. HIVberoepsrisico van snijdende specialisten en operatiekamermedewerkers in het St. Lucas Ziekenhuis te Amsterdam. Ned Tijdschr Geneeskd 1989;133:2388-91 12 Hussain S, Latif A, Choudhary A. Risks to surgeons, a survey of accidental injuries during operations. Br J Surg 1988;75:314-16 13 Leentvaar-Kuypers A, Dekker E, Post-Kernan W, et al. Frequentie van prikaccidenten met door hepatitis B-virus besmet bloed bij ziekenhuismedewerkers in 15 ziekenhuizen in Amsterdam en omgeving in 1985. Ned Tijdschr Geneeskd 1987;131:2188-90 14 Geberding J. Occupational HIV transmission: risk reduction. State Art Rev Occup Med 1989;4:21-4 15 Schecter W. HIV transmission to surgeons. State Art Rev Occup Med 1989;4:65-9 16 Ho DD, et al, Quantification of HIV type I in the blood of infected persons. N Engl J Med 1989;321:1621-5 17 Guertler L, et al. Comparison of the age distribution of anti HIV-1 and anti HBC in an urban population from Malawi. In abstracts V International Conference on AIDS, Montreal, June 1989 18 Jagger I, Hunt E, Brand-Elnaggar J, et al. Rates of needlestick injury caused by various devicesin a university hospital. N Engl J Med 1988;319:284-8 19 Bessinger C. Preventing transmission of HIV during operations. Surg Gynecol Obst 1988;167:287-9 20 Brough S, Hunt T, Barrie W. Surgical glove perforations Br J Surg 1988;75:317 21 Anonymous. Recommendations for prevention of HIV transmission in health care settings. MMWR 1987;36(s-2):2-18 22 Giachino S, Profilt A, Taine W. Expected contamination of the orthopedic surgeon's conjunctives. Can J Surg 1988; 31:51-2 23 Cobelens F. Risico's en preventie van HIV-overdracht in beroepssituaties. Amsterdam: Nationale Commissie AIDSbestrijding, 1990 24 McCray E. Occupational risk of AIDS among health care workers. N Engl J Med 1986;314:1127-32