Are US hospitals making progress in implementing guidelines for prevention of Mycobacterium tuberculosis transmission?

BACKGROUND: Outbreaks of tuberculosis (TB) in hospitals have occurred when the Centers for Disease Control and Prevention (CDC) guideline recommendations for preventing the transmission of Mycobacterium tuberculosis were not fully implemented. OBJECTIVE: To determine whether US hospitals are making progress in implementing the CDC guidelines for preventing TB. METHODS: In 1992, we surveyed all public (city, county, Veterans Affairs, and primary medical school-affiliated) US hospitals (n = 632) and 444 (20%) random samples of all private hospitals with 100 beds or more. In 1996, we resurveyed 136 random samples (50%) of all 1992 respondent hospitals with 6 or more TB admissions in 1991. RESULTS: Of the 1076 hospitals surveyed in 1992, 763 (71%) respondents returned a completed questionnaire. Among these, 536 (71%) of 755 reported having rooms that met CDC criteria for acid-fast bacilli isolation, ie, negative air pressure, 6 or more air exchanges per hour, and air directly vented to the outside. The predominant respiratory protective device for health care workers was nonfitted surgical mask and attending physicians were infrequently (50%) included in tuberculin skin-testing programs. In the 1996 resurvey, 103 (76%) of 136 respondents returned a completed questionnaire. Of these, 99 (96%) reported having rooms that met CDC criteria for acid-fast bacilli isolation. The N95 respiratory protective devices were predominantly used by health care workers, and attending physicians were increasingly (69%) included in the hospitals' tuberculin skin-testing programs. CONCLUSIONS: Most US hospitals are making progress in the implementation of CDC guidelines for preventing the transmission of M tuberculosis.

The National Nosocomial Infections Surveillance System: plans for the 1990s and beyond.

The National Nosocomial Infections Surveillance (NNIS) System is an ongoing collaborative surveillance system among the Centers for Disease Control (CDC) and United States hospitals to obtain national data on nosocomial infections. This system provides comparative data for hospitals and can be used to identify changes in infection sites, risk factors, and pathogens, and develop efficient surveillance methods. Data are collected prospectively using four surveillance components: hospital-wide, intensive care unit, high-risk nursery, and surgical patient. The limitations of NNIS data include the variability in case-finding methods, infrequency or unavailability of culturing, and lack of consistent methods for post-discharge surveillance. Future plans include more routine feedback of data, studies on the validity of NNIS data, new components, a NNIS consultant group, and more rapid data exchange with NNIS hospitals. Increasing the number of NNIS hospitals and cooperating with other agencies to exchange data may allow NNIS data to be used better for generating benchmark nosocomial infection rates. The NNIS system will continue to evolve as it seeks to find more effective and efficient ways to measure the nosocomial infection experience and assess the influence of patient risk, changes in the delivery of hospital care, and changes in infection control practices on these measures.

Surgical wound infection rates by wound class, operative procedure, and patient risk index. National Nosocomial Infections Surveillance System.

To perform a valid comparison of rates among surgeons, among hospitals, or across time, surgical wound infection (SWI) rates must account for the variation in patients' underlying severity of illness and other important risk factors. From January 1987 through December 1990, 44 National Nosocomial Infections Surveillance System hospitals reported data collected under the detailed option of the surgical patient surveillance component protocol, which includes definitions of eligible patients, operations, and nosocomial infections. Pooled mean SWI rates (number of infections per 100 operations) within each of the categories of the traditional wound classification system were 2.1, 3.3, 6.4, and 7.1, respectively. A risk index was developed to predict a surgical patient's risk of acquiring an SWI. The risk index score, ranging from 0 to 3, is the number of risk factors present among the following: (1) a patient with an American Society of Anesthesiologists preoperative assessment score of 3, 4, or 5, (2) an operation classified as contaminated or dirty-infected, and (3) an operation lasting over T hours, where T depends upon the operative procedure being performed. The SWI rates for patients with scores of 0, 1, 2, and 3 were 1.5, 2.9, 6.8, and 13.0, respectively. The risk index is a significantly better predictor of SWI risk than the traditional wound classification system and performs well across a broad range of operative procedures.

Comparison of rates of nosocomial infections in neonatal intensive care units in the United States. National Nosocomial Infections Surveillance System.

To determine nosocomial infection (NI) rates among neonatal intensive care units (NICUs) that are useful for interhospital comparison, we analyzed data reported in 1986-1990 from 35 hospitals that have level III NICUs and used standard National Nosocomial Infections Surveillance protocols and NI site definitions. Overall rates of NI were calculated as the number of NI per 100 patients (overall NI patient rates) or the number of NI per 1,000 NICU patient-days (overall NI patient-day rates). A strong positive association was found between overall NI patient rates and the neonates' average length of stay, a marker for duration of exposure to important risk factors. No correlation was found between overall NI patient-day rates and average length of stay. However, a strong positive correlation between overall NI patient-day rates and a measure of device utilization (total device-days/total patient-days x 100) was found. Additionally, a positive correlation between overall NI patient rates and device utilization was found. Stratification among the three birthweight groups (less than 1,500 g, 1,500-2,500 g, greater than 2,500 g) did not eliminate the need to control for variations in these factors among NICUs. Device-associated, device-day infection rates, calculated as the number of umbilical or central line-associated blood-stream infections per 1,000 umbilical or central line-days and the number of ventilator-associated pneumonias per 1,000 ventilator days, were not correlated with a unit's site-specific device utilization. These data suggest that calculation of device-associated NI rates in NICUs using device-days as the denominator helps to control for the duration of exposure to the primary risk factor and will be more meaningful for purposes of interhospital comparison.

Nosocomial infections in elderly patients in the United States, 1986-1990. National Nosocomial Infections Surveillance System.

We analyzed 101,479 nosocomial infections in 75,398 adult patients (greater than 15 years) that were reported to the National Nosocomial Infections Surveillance (NNIS) system between 1986 and 1990 by 89 hospitals using the NNIS hospital-wide surveillance component. Overall, 54% of the infections occurred in elderly patients (greater than or equal to 65 years). In the elderly, 44% of the infections were urinary tract infections (UTIs), 18% were pneumonias, 11% were surgical wound infections (SWIs), 8% were bloodstream infections (BSIs), and the remainder were infections at other sites. When we compared the infections in elderly patients with those in younger adult patients, ages 15 to 64 years, a far greater percentage of the infections in elderly patients were UTIs, and there were more pneumonias than SWIs. Elderly and younger patients with ventilator-associated pneumonia were about 1.5 times more likely to develop a secondary BSI than those with pneumonia not associated with ventilator use. When the pathogens isolated from the infections were compared to those reported to the NNIS system in 1984, the percentage that were coagulase-negative staphylococci had increased in both elderly and younger patients. The patient died in 12% of all of the infections. Surveillance personnel reported that 54% of the infections in elderly infected patients who died were related to death compared with 59% in younger infected patients who died. When the infection was related to the patient's death, it was most often pneumonia or a BSI. The risk of an infection-related death was significantly higher when the infected patient developed a secondary BSI. Infection prevention efforts should target infections that occur frequently, are amenable to intervention, and have an adverse outcome.

Secular trends in nosocomial primary bloodstream infections in the United States, 1980-1989. National Nosocomial Infections Surveillance System.

More than 25,000 primary bloodstream infections (BSIs) were identified by 124 National Nosocomial Infections Surveillance System hospitals performing hospital-wide surveillance during the 10-year period 1980-1989. These hospitals reported 6,729 hospital-months of data, during which time approximately 9 million patients were discharged. BSI rates by hospital stratum (based on bed size and teaching affiliation) and pathogen groups were calculated. In 1989, the overall BSI rates for small (less than 200 beds) nonteaching, large nonteaching, small (less than 500 beds) teaching, and large teaching hospitals were 1.3, 2.5, 3.8, and 6.5 BSIs per 1,000 discharges, respectively. Over the period 1980-1989, significant increases (p less than 0.0001) were observed within each hospital stratum, in the overall BSI rate and the BSI rate due to each of the following pathogen groups: coagulase-negative staphylococci, Staphylococcus aureus, enterococci, and Candida species. In contrast, the BSI rate due to gram-negative bacilli remained stable over the decade, in all strata. Except for small nonteaching hospitals, the greatest increase in BSI rates was observed in coagulase-negative staphylococci (the percentage increase ranged between 424% and 754%), followed by Candida species (219-487%). In small nonteaching hospitals, the greatest increase was for S. aureus (283%), followed by enterococci (169%) and coagulase-negative staphylococci (161%). Our analysis documents the emergence over the last decade of coagulase-negative staphylococci as one of the most frequently occurring pathogens in BSI.

[3-(1,4-Cyclohexadienyl)-L-alanine,8-lysine]vasopressin: synthesis and some pharmacological properties.

[3-(1,4-Cyclohexadienyl)-L-alanine,8-lysine]vasopressin, otherwise known as [3-(2,5-dihydrophenylalanine),8-lysine]vasopressin or [DiHPhe3]lysine-vasopressin, has been synthesized in an attempt to utilize 2,5-dihydrophenylalanine (DiHPhe) to evaluate the contribution of aromaticity in position 3 to biological activity. The analogue has the same primary structure as lysine-vasopressin, except that two additional hydrogen atoms are present on the ring moiety of the phenylalanine residue in position 3. The key intermediate was the protected nonapeptide N-carbobenzoxy-S-benzyl-L-cysteinyl-L-tyrosyldihydrophenyl-L-alanyl-L-glutaminyl-L-asparaginyl-S-benzyl-L-cysteinyl-L-prolyl-N epsilon-tosyl-L-lysylglycinamide that was synthesized stepwise by the solid-phase technique. Deprotection with sodium in liquid ammonia was followed by sulfhydryl oxidation with I2 to give the hormone analogue. [DiHPhe3]lysine-vasopressin exhibited 125--130 units/mg of antidiuretic, 129--132 units/mg of rat pressor, and 6 units/mg of rat uterus contracting activity. To confirm the presence of DiHPhe in the analogue, an enzymatic procedure employing Aspergillus oryzae was developed that liberates in high yield the amino acid residue in position 3 of the posterior pituitary hormone structure. This study should be applicable to other biologically active peptides.

Line-associated bloodstream infections in pediatric intensive-care-unit patients associated with a needleless device and intermittent intravenous therapy.

OBJECTIVES: To determine risk factors for an increase in line-associated bloodstream infections (BSIs) in three pediatric intensive-care units at one hospital that recently had changed brands of needleless access device. DESIGN: Retrospective case-control studies; review of the units' infection control policies and procedures for accessing and replacing components of needleless access devices. SETTING: A community tertiary-care hospital's three pediatric intensive-care units. PATIENTS: Children in one of the three intensive-care units with a central venous catheter in place during January 1, 1995, through May 15, 1996, who developed laboratory-confirmed primary BSI. Children who had central venous catheters in place for >48 hours and who did not develop BSI were chosen randomly as controls. RESULTS: Eight patients met the case definition; they had 11 episodes of BSI. Multivariate analysis identified duration of catheterization and exposure to the IVAC first-generation needleless device as independent risk factors for BSI. Compared with patients from another pediatric intensive-care unit in which the IVAC device also was used but in which an increased BSI rate did not occur, patients from the unit with an increased BSI rate were more likely to receive intermittent (vs continuous) intravenous therapy through one or more lumens. In both units, the IVAC device valve component was replaced every 6 days, and the endcap used to cover the valve (when connected to an unused lumen) was replaced every 24 hours or after each access. The BSI rate returned to baseline after institution of a policy to replace the entire IVAC device, valve, and endcap every 24 hours. CONCLUSIONS: An increased risk of BSI was associated with use of the IVAC first-generation needleless device when replaced every 6 days. This increased risk may have been more pronounced in one pediatric intensive-care unit, because patients were more likely to receive intermittent intravenous therapy. Intermittent intravenous therapy or central venous catheter flushing practices may be important determinants of BSI risk.

Increased bloodstream infection rates in surgical patients associated with variation from recommended use and care following implementation of a needleless device.

OBJECTIVE: To determine if an apparent increase in bloodstream infections (BSIs) in patients with central venous catheters (CVCs) was associated with the implementation of a needleless access device. DESIGN: Retrospective cohort study using a derived CVC-days factor for estimating appropriate denominator data. SETTING: A 350-bed urban, acute, tertiary-care hospital. METHODS: BSI surveillance data were obtained, and high-risk areas for BSIs were determined. A random 5% sample of medical records was used to estimate CVC days, and a cohort study was conducted to compare BSI rates before and during needleless device use. A survey was conducted of nursing needleless-device practices. RESULTS: The surgical intensive-care unit (SICU), the medical intensive-care unit, and the solid organ transplant unit (OTU) were identified as high-risk units. Using existing surveillance BSI data and the estimated CVC days, the catheter-related BSI rates in the high-risk surgical patients were significantly higher during the needleless-device period compared with the preneedleless-device period (SICU, 9.4 vs 5.0/1,000 CVC days; OTU, 13.6 vs 2.2/1,000 CVC days). A survey of the nurses revealed that 60% to 70% were maintaining the needleless devices correctly. CONCLUSION: We observed a significant increase in the BSI rate in two surgical units, SICU and OTU, associated with introduction of a needleless device. This increase occurred shortly after the needleless device was implemented and was associated with nurses' unfamiliarity with the device, and needless-device use and care practices different from the manufacturer's recommendations.

Serratia marcescens outbreak associated with extrinsic contamination of 1% chlorxylenol soap.

OBJECTIVES: To determine risk factors for Serratia marcescens infection or colonization, and to identify the source of the pathogen and factors facilitating its persistence in a neonatal intensive-care unit (NICU) during an outbreak. DESIGN: Retrospective case-control study; review of NICU infection control policies, soap use, and handwashing practices among healthcare workers (HCWs); and selected environmental cultures. SETTING: A university-affiliated tertiary-care hospital NICU. PATIENTS: All NICU infants with at least one positive culture for S marcescens during August 1994 to October 1995. Infants who did not develop S marcescens infection or colonization were selected randomly as controls. RESULTS: Thirty-two patients met the case definition. On multivariate analysis, independent risk factors for S marcescens infection or colonization were having very low birth weight (< 1,500 g), a patent ductus arteriosus, a mother with chorioamnionitis, or exposure to a single HCW. During January to July 1995, NICU HCWs carried their own bottles of 1% chlorxylenol soap, which often were left standing inverted in the NICU sink and work areas. Cultures of 16 (31%) of 52 samples of soap and 1 (8%) of 13 sinks yielded S marcescens. The 16 samples of soap all came from opened 4-oz bottles carried by HCWs. DNA banding patterns of case infant, HCW soap bottle, and sink isolates were identical. CONCLUSIONS: Extrinsically contaminated soap contributed to an outbreak of S marcescens infection. Very-low-birth-weight infants with multiple invasive procedures and exposures to certain HCWs were at greatest risk of S marcescens infection or colonization.

Association between implementation of CDC recommendations and ventilator-associated pneumonia at selected US hospitals.

BACKGROUND: To assess whether selected recommendations in the Centers for Disease Control and Prevention "Guideline for Prevention of Nosocomial Pneumonia" were being implemented and having an impact on the occurrence of ventilator-associated pneumonia (VAP) at US hospitals, we surveyed hospitals participating in the National Nosocomial Infections Surveillance (NNIS) system. METHODS: We mailed a questionnaire to the infection control practitioner of each NNIS hospital in 1995 and used data from the NNIS system to calculate annual rates of VAP. RESULTS: Of the 188 hospitals surveyed, 179 (95%) returned completed questionnaires. Of these, 175 (98%) had implemented the recommended change of mechanical-ventilator breathing circuits at 48-hour or greater intervals. Of 110 hospitals using the hygroscopic condenser-humidifiers or heat-moisture exchangers with ventilators, 102 (93%) changed the hygroscopic condenser-humidifiers or heat-moisture exchangers routinely, and of 98 hospitals using bubbling humidifiers, 96 (98%) used sterile water to fill these humidifiers. Other practices for which the guideline provides no recommendation and their frequency of use by NNIS hospitals include use of hygroscopic condenser-humidifiers or heat-moisture exchangers (110/179 [61%]) and use of bacterial filters in anesthesia machines (128/171 [61%]). There was a significant decrease in the VAP rate from 1987 to 1998. CONCLUSION: Most NNIS hospitals had implemented selected recommendations in the Centers for Disease Control and Prevention "Guideline for Prevention of Nosocomial Pneumonia" before the final publication of the revised guideline. Further studies are needed to assess the impact of these recommendations on the occurrence of VAP.

Status of tuberculosis infection control programs at Texas hospitals, 1989 through 1991.

BACKGROUND: Paralleling the resurgence of tuberculosis (TB) in the United States, the reported number of persons with TB in Texas increased by 33% during 1985 through 1992, the third largest rise among all the states. This increase prompted us to survey hospitals in Texas to determine their degree of compliance with recommendations in the Centers for Disease Control and Prevention TB guidelines. METHODS: In April 1992, we mailed a voluntary questionnaire about TB infection control practices, health care worker tuberculin skin testing procedures, and Mycobacterium tuberculosis laboratory methods to a convenience sample of hospitals in Texas. RESULTS: Of 180 hospitals surveyed, 151 (83%) returned completed questionnaires. Of these, 90 (60%) were nonteaching community hospitals; 28 (19%) were teaching community hospitals; 13 (9%) were university-affiliated hospitals; and 20 (13%) were other hospitals. The number of hospitals to which patients with TB were admitted increased from 98 (65%) in 1989 to 122 (81%) in 1991. Respondent hospitals had a mean of 183 acute care beds (median 100, range 5 to 999), 6 acid-fast bacillus isolation rooms (median 2, range 0 to 57) and 7.5 admissions/year of patients with TB (median 2, range 0 to 202). Of hospitals responding to specific questions, 20% (27/137) admitted patients with multidrug-resistant TB, 18% (25/140) reported not having any acid-fast bacillus isolation rooms, and 28% (35/125) had no rooms meeting all of the Centers for Disease Control and Prevention criteria for acid-fast bacillus isolation (negative air pressure, > or = 6 air changes per hour, and air directly vented to the outside). The tuberculin skin test conversions among health care workers rose from 246 (0.6%) in 1989 to 547 (0.9%) in 1991. CONCLUSION: Although the number of Texas hospitals admitting patients with TB increased during 1989 through 1991, many facilities still did not have infection control practices consistent with the 1992 Centers for Disease Control and Prevention TB guidelines.

Serratia marcescens transmission in a pediatric intensive care unit: a multifactorial occurrence.

BACKGROUND: Fourteen patients in the pediatric cardiac intensive care unit (CICU) had > or =1 positive culture for a single strain of Serratia marcescens from April through December 1995 (study period). OBJECTIVES: To identify risk factors for S marcescens infection or colonization in a pediatric CICU. METHODS: Retrospective case-control study. Assessment of CICU infection control practices and patient exposure to CICU health care workers (HCWs). Epidemiologic-directed cultures of the environment and HCWs' hands were obtained. SETTING: Pediatric CICU. PATIENTS: Fourteen patients in the pediatric CICU had > or =1 positive culture for a single strain of S marcescens from April through December 1995 (study period). CICU patients who did not have S marcescens infection or colonization during the study period were randomly selected as controls. RESULTS: A case patient was more likely than a noncase patient to have exposure to a single HCW (odds ratio [OR], 19.5; 95% CI, 2.6-416; P<.003); however, this association was not adequately explained by epidemiologic or microbiologic studies. Interviews suggested that during the outbreak period, handwashing frequency among HCWs might have been reduced because of severe hand dermatitis. CONCLUSIONS: A combination of factors, including breaks in aseptic technique, reduced frequency of handwashing among HCWs before and between caring for patients, decreased attention to infection control practices, and environmental contamination may have indirectly contributed to this S marcescens infections outbreak.

Risk factors for acquisition of vancomycin-resistant enterococci among patients on a renal ward during a community hospital outbreak.

BACKGROUND: During an outbreak of vancomycin-resistant enterococcal (VRE) infection and colonization at a community hospital in Indianapolis, Indiana, we performed a case-control study of patients on the hospital's renal unit to determine risk factors for acquisition of VRE among this potentially high-risk patient population. METHODS: Twenty-four renal patients with VRE colonization/infection (ie, case-patients) were compared by univariate and multivariate analyses with 29 renal patients with nosocomially acquired vancomycin-susceptible enterococcal infection and colonization (ie, controls). RESULTS: Age and length of hospitalization were similar between the VRE case-patients and the vancomycin-susceptible enterococcal control-patients, but case-patients had higher Acute Physiology and Chronic Health Evaluation II scores and received significantly greater numbers of antimicrobials and significantly more days of antimicrobials during the 60 days preceding the first positive enterococcal culture. In an assessment of the appropriateness of vancomycin use, one third of vancomycin orders were found to be inappropriate in both patient groups. CONCLUSIONS: Our data show that among renal patients, those who are severely ill and receive multiple and prolonged courses of antimicrobials are at greatest risk for acquiring VRE infection or colonization. The Centers for Disease Control and Prevention recommends that hospitals develop a comprehensive plan to prevent and control infection and colonization of patients with VRE. This plan should include prompt identification of affected patients, initiation of isolation precautions to prevent patient-to-patient transmission of VRE, and prudent use of antimicrobials, including vancomycin.

A new incision for subfascial ligation of perforating veins in chronic venous ulcers of the leg.

A new incision is described for subfascial ligation of perforating veins in patients with chronic venous ulcers of the leg. It avoids the complications encountered with the conventional midline posterior approach.

Birds disperse ixodid (Acari: Ixodidae) and Borrelia burgdorferi-infected ticks in Canada.

A total of 152 ixodid ticks (Acari: Ixodidae) consisting of nine species was collected from 82 passerine birds (33 species) in 14 locations in Canada from 1996 to 2000. The Lyme disease spirochete Borrelia burgdorferi Johnson, Schmidt, Hyde, Steigerwaldt & Brenner was cultured from the nymph of a blacklegged tick, Ixodes scapularis Say, that had been removed from a common yellowthroat, Geothlypis trichas L., from Bon Portage Island, Nova Scotia. As a result of bird movement, a nymphal I. scapularis removed from a Swainson's thrush, Catharus ustulatus incanus (Godfrey), at Slave Lake, Alberta, during spring migration becomes the new, most western and northern record of this tick species in Canada. Amblyomma longirostre Koch, Amblyomma sabanerae Stoll, and Ixodes baergi Cooley & Kohls are reported for the first time in Canada. Similarly, Amblyomma americanum L., Arnblyomma maculatum Koch, and ixodes muris Bishopp & Smith are reported for the first time on birds in Canada. After removal of an I. muris gravid female from a song sparrow, Melospiza melodia Wilson, at St. Andrews, New Brunswick, eggs were laid, which developed into larvae, and this new tick-host record demonstrates that birds have the potential to start a new tick population. We conclude that passerine birds disperse several species of ixodid ticks in Canada, and during spring migration translocate ticks from the United States, and Central and South America, some of which are infected with B. burgdorferi.

Differential clastogenic sensitivity of heterochromatin and euchromatin: evidence from an in vivo study made on a submammalian vertebrate.

One of the properties often attributed to heterochromatin is its susceptibility to induced aberrations and exchanges. However, earlier studies made mostly on different mammalian in vitro cell lines on the distribution of aberrations within euchromatin and heterochromatin at metaphase chromosome level have given contradictory results. In the present study, an attempt has been made to evaluate the clastogenic sensitivity of heterochromatin and euchromatin using somatic chromosome complements of a submammalian vertebrate as experimental model and considering both chromosome aberrations and SCEs as end points.

Clinical evaluation of Tc-99m cystine. A new renal radiopharmaceutical.

Tc-99m cystine has been proven to be a good renal agent in animals, but its clinical evaluation has not been reported. In this study, Tc-99m cystine was used for evaluation of renal function in normal subjects and patients with chronic renal failure as well as in renal transplant patients. The results are compared with similar studies that used Tc-99m DTPA and Tc-99m GHA. The clearance values also have been compared with I-131 OIH clearance. The results show that Tc-99m cystine has good radiopharmaceutical characteristics suitable for evaluation of both renal function as well as morphology.

Clinical evaluation of Tc-99m cystine. A new renal radiopharmaceutical.

Tc-99m cystine has been proved to be a good renal agent in animals. Its clinical evaluation has not been reported. In this study, Tc-99m cystine is used for evaluation of renal function in normal subjects and patients with chronic renal failure as well as in renal transplant patients. The results are compared with similar studies using Tc-99m DTPA and Tc-99m GHA. The clearance values also are compared with I-131 OIH. The results show that Tc-99m cystine has good radiopharmaceutical characteristics suitable for evaluation of both renal function as well as morphology.

The seroepidemiology of toxoplasmosis in the lower Fraser Valley of British Columbia.

OBJECTIVE: To determine the seroprevalence of toxoplasmosis in vegetarian and nonvegetarian members of different ethnic communities in the lower Fraser Valley of British Columbia. DESIGN: Serum samples were collected from 2027 participants drawn from various ethnic groups and tested by elisa for the presence of immunoglobulin (Ig) G and IgM antibodies to Toxoplasma gondii. Coded questionnaires requesting information relevant to the study were completed by each participant. The study population comprised 1334 females and 693 males; ages ranged from 17 to 102 years. MAIN RESULTS: Four hundred and nineteen (20.7%) individuals were IgG positive with titres ranging from 1:100 to 1:3200. IgM antibodies were detected in only four individuals. The seroprevalence rose with increase in age but there was no significant difference between males and females. A positive correlation was shown between ingestion of meat and between consumption of unpasteurized milk and antibodies to T gondii. Eighty per cent of females between the ages of 17 and 40, of all ethnic origins, were seronegative. Seropositivity did not differ between cat owners and non-cat owners. CONCLUSIONS: Women of childbearing age are at risk of acquiring toxoplasmosis during pregnancy and of transmitting the infection transplacentally. Consumption of undercooked meat and unpasteurized milk may result in the acquisition of toxoplasmosis. Data suggest that acquisition of toxoplasmosis is more likely via environmental oocysts or cysts in food source animals than by direct contact with cats.