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Rapid control of a scabies outbreak at a tertiary care hospital without ward closure
American Journal of Infection Control 40 (2012) 451-5
Contents lists available at ScienceDirect
American Journal of Infection Control
American Journal of Infection Control
journal homepage: www.ajicjournal.org
Major article
Rapid control of a scabies outbreak at a tertiary care hospital without ward closure Anjum Khan MBBS, MSc, CIC a, Sharon O’Grady ART, BAS, CIC b, Matthew Paul Muller MD, PhD, FRCPC a, c, * a
Infection Prevention and Control Service, St. Michael’s Hospital, Toronto, ON, Canada Infection Control, Bridgepoint Health, Toronto, ON, Canada c Department of Medicine, University of Toronto, Toronto, ON, Canada b
Key Words: Infection control Sarcoptes scabei Ectoparasitic infestation Mass prophylaxis
Background: Although scabies outbreaks in hospitals are frequent, the optimal approach to management of these outbreaks has not yet been defined. We describe a hospital scabies outbreak that was successfully controlled without ward closure. Methods: An outbreak of scabies at a teaching hospital and subsequent control measures were investigated. Outcomes included the number of cases affecting patients and staff, number of patients and staff requiring prophylaxis, duration of the outbreak, and cost of the outbreak. Outcomes were compared with those in a similar outbreak occurring at the same hospital 20 years earlier and with other published descriptions of hospital scabies outbreaks. Results: In January 2010, a patient who had undergone renal transplantation was admitted 3 times to St. Michael’s Hospital, but a diagnosis of scabies was not considered until the final admission. Widespread exposure of patients and staff on 2 wards prompted the establishment of an outbreak management team. Initial interventions focused on isolation and treatment of the index case and on contact tracing to identify and treat secondary cases and to offer prophylaxis to direct contacts. Five symptomatic staff members and 2 patient cases were quickly identified, an outbreak was declared, and mass simultaneous prophylaxis was initiated on the 2 involved wards. A single case occurred 2 weeks after the mass prophylaxis program in a staff member who had not received the prophylaxis. Six weeks after the onset of symptoms, the end of the outbreak was declared. No additional cases have been reported up to the time of publication. The total cost of the outbreak was $20,000. Conclusions: Early recognition of crusted scabies is essential to prevent outbreaks. Once an outbreak occurs, prompt control of the index patient and rapid tracing of contacts to identify secondary cases are necessary. When prolonged exposure to a case of crusted scabies results in multiple secondary cases, institution of simultaneous mass prophylaxis is the most efficient strategy for terminating the outbreak and can be implemented without ward closure. Copyright Ó 2012 by the Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.
Scabies is an endemic skin infestation caused by the mite Sarcoptes scabei var hominis.1,2 In most individuals, classic scabies causes intense pruritus and an erythematous papular rash in a characteristic distribution; however, in immunocompromised, neurologically impaired, or debilitated elderly patients, scabies may present with diffuse scaly plaques, thickened nails, and no pruritus.1,2 This form of scabies, called crusted scabies, is associated with a significantly higher burden of mites than classic scabies.2 Whereas transmission from patients with classic scabies results from prolonged skin-to-skin contact, transmission from a patient with crusted
* Address correspondence to Matthew Paul Muller, MD, PhD, FRCPC, St. Michael’s Hospital, Infection Prevention and Control Service, 30 Bond Street, Toronto, ON M5B 1W8, Canada. E-mail address: [email protected] (M.P. Muller). Conflict of interest: None to report.
scabies can result from transient direct contact or from indirect contact with bedding, clothing, or other contaminated fomites.2 Scabies has been associated with outbreaks in institutional settings, including acute care medical facilities. Outbreaks in acute care settings often follow the admission of a patient with unrecognized crusted scabies.3-5 Large numbers of patients and staff are often exposed before crusted scabies is diagnosed, and such outbreaks can be widespread, prolonged, and difficult to control.3,6-8 Scabies outbreaks often provoke significant anxiety among staff and can result in ward closure, disruption of medical services, and significant excess costs.3,5-8 Despite the challenges posed by scabies outbreaks in acute care facilities, there remains no consensus on the optimal approach to controlling outbreaks in this setting. We report a scabies outbreak in an acute care hospital, with spread to a second rehabilitation facility, that was rapidly controlled without ward closure through the rapid implementation
0196-6553/$36.00 - Copyright Ó 2012 by the Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved. doi:10.1016/j.ajic.2011.05.014
452
A. Khan et al. / American Journal of Infection Control 40 (2012) 451-5 Outbreak declared and mass prophylaxis initiated 22 Feb
10 9 8 7 6 5 4 3 2 1 0
Outbreak declared over 22 April
Index case diagnosed with crusted scabies 19 Feb
3-9 Jan
10-16 jan 17-23 jan 24-30 Jan 31-6 Feb 7-13 Feb 14-20 Feb 21-27 Feb 28 Feb-6 7-13 mar 14-20 Mar 21-27 Mar 28-3 Apr 4-10 Apr 11-17 Apr 18-24 Apr
Mar Fig 1. Epidemic curve. The black bar represents staff cases in the rehabilitation facility; the gray bar, staff cases in the acute care facility; the checked bar, patient cases in the acute care facility. The dashed line represents admission of the index patient to the acute care facility.
of effective infection control measures, including simultaneous mass prophylaxis. METHODS We describe an outbreak of scabies that occurred at St. Michael’s Hospital, a 500-bed acute care teaching hospital in Toronto, Canada, and an affiliated complex care hospital (designated facility A). Here we describe all of the interventions used to control transmission of scabies during the outbreak in sufficient detail to be reproducible and useful to other acute care facilities confronted with a scabies exposure or outbreak. In accordance with the case definition used during the outbreak, patients and staff members were considered to have scabies if they developed severe pruritus and a characteristic rash after admission to or employment on any of the affected units during or after January 2010. For patients with an atypical clinical presentation, a positive skin scraping or skin biopsy was required for confirmation; however, given the limited sensitivity of skin scrapings, cases with characteristic clinical findings but negative skin scrapings were included. The decision of whether or not to perform skin scraping was left to the discretion of the treating physician. Outcomes assessed include the duration of the outbreak, the number of affected patients and staff, and the number of patients and staff requiring prophylaxis. We compared these outcomes with those from a similar outbreak at St. Michael’s Hospital occurring 20 years earlier.6 Although we did not conduct a formal cost analysis, we evaluated the differences in cost between the current and previously reported outbreak using the same categories in both outbreaks (ie, medication costs, ward closure, absenteeism, overtime, increased length of hospital stay, and mailing costs). RESULTS Initial case presentation In January 2010, a 68-year-old female undergoing renal transplantation was admitted to the St. Michael’s Hospital internal medicine inpatient unit with right-sided deep venous thrombosis and urinary tract infection. Her immunosuppressive regimen consisted of prednisone 20 mg daily and tacrolimus 3 mg twice daily. A diffuse maculopapular rash noted on admission was treated with 0.1% betamethasone cream. The day before discharge, the patient complained of pruritus and was given an antihistamine. After 2 weeks in the hospital, she was discharged to facility A (Fig 1).
Six days after discharge, the patient was readmitted to the hospital with recurrent urinary tract infection initially to our internal medicine unit and later to our nephrology ward. On admission, she complained of pruritus, and examination revealed thickened dystrophic nails with hyperkeratosis on the elbows and feet. During hospitalization, she developed diffuse erythroderma and progressive hyperkeratosis on her hands, elbows, legs, and feet. Dermatology was consulted, and a skin biopsy was performed. The pathology was interpreted as nondiagnostic but consistent with a resolving drug eruption. The patient was treated with 1% hydrocortisone cream and 3% salicyclic acid topically. Ten days later, she was transferred back to facility A. Within 1 day of the patient’s transfer (and 16 days after her initial admission to facility A), staff members at facility A began manifesting symptoms consistent with scabies. Within 6 days of the transfer, 12 staff members were diagnosed with scabies. After 1 week at facility A, the patient was readmitted to St. Michael’s Hospital with confusion and a diffuse rash. Because of the scabies outbreak at facility A, the patient was placed on precautions on arrival in the emergency department, and her rash was reevaluated. A repeat skin biopsy confirmed the diagnosis of crusted scabies. Treatment with ivermectin was initiated, but the patient died of septic shock secondary to a perforated duodenal ulcer before the completion of treatment. Initial investigation and management of scabies exposure The identification of this patient with crusted scabies admitted twice for a total of 24 days with no precautions prompted the immediate creation of an outbreak management team (OMT) with representation from all involved units, infection control, employee health, environmental services, pharmacy, public relations, and administration. The OMT immediately initiated contact tracing to identify and offer prophylaxis to all patients and staff who had direct exposure to the index patient or her immediate environment, including mobile staff, such as phlebotomists and radiology technicians; notification of facilities and family physicians of exposed patients already discharged or transferred; and development of a communication strategy to inform staff about the situation and encourage staff members with pruritic rash to present to the hospital’s employee health department for assessment (Table 1). Five staff members with scabies, 4 from the internal medicine unit and 1 from the nephrology unit, were rapidly identified via contact tracing. All identified staff members were nurses who cared for the index patient except for one environmental service worker
A. Khan et al. / American Journal of Infection Control 40 (2012) 451-5
453
Table 1 Measures implemented to control scabies after identification of exposure or nosocomial transmission Goal
Intervention
Measures implemented after recognition of exposure Management of index Private room with barrier precautions (ie, gown, patient with crusted gloves) plus hand hygiene on room entry and exit scabies Initiation of treatment Environmental cleaning Handling of contaminated linens
Contact tracing
Identification of patient contacts of the index patient Identifications of staff contacts of the index patient Management of contacts
Management of family members Internal communication
Communication to staff members in affected areas
Comment Hand hygiene with soap/water is preferred on room exit; ensure no gap between gowning and gloving before room entry. Booties not recommended. Treatment with ivermectin (200 mg/kg orally) and 5% permethrin. Terminal (ie, “isolation room”) cleaning for rooms recently occupied by the index patient, and standard daily cleaning of the index patient’s room. Linens were bagged and transported to the laundry. Staff in the laundry use gowns/gloves routinely. Linens were washed in hot water. No additional precautions were used. Roommates from all admissions, and patients admitted directly into a bed previously occupied by the index case. All staff members who had direct contact with the index patient or the index patient’s bedside environment, including mobile staff. All contacts were evaluated for symptomatic scabies. All contacts received 5% permethrin cream as treatment or prophylaxis. Discharged or transferred patient contacts were notified by phone and/or mail. Treatment with 5% permethrin was provided free of charge to all family members of symptomatic patients or staff members. Staff members were informed of the situation, instructed to contact employee health if symptomatic (and to not work), and informed that prophylaxis would be provided without charge.
Additional measures added after nosocomial transmission identified and outbreak declared External communication Notification of local public health authorities Internal communications Communication to all staff members Hospital staff were informed of the situation. Signs informing visitors and staff members of required procedures were posted on outbreak units. Staff was reassured that a control strategy was in place and that staff members would receive prophylaxis. Administration of prophylaxis with 5% permethrin Over a 12-hour period all patients without medical contraindications were treated, Simultaneous mass prophylaxis of patients to all patients on the outbreak units patient clothing and bedding was changed, and rooms were cleaned. Health care workers used gowns and gloves for all patient care during this 12-hour period. Simultaneous mass Administration of prophylaxis with 5% permethrin Staff prophylaxis was initiated at the same time as patient prophylaxis. Staff members prophylaxis of staff to all staff members working on the outbreak were given 5% permethrin at the end of their shifts to self-treat overnight. Staff units members not working that day were called at home and asked to self-treat before their next shift. A staff member who could not be contacted before her shift was required to use barrier precautions for patient care and to receive prophylaxis after her shift. All but one staff member received prophylaxis within 4 days, and no staff member refused treatment. The costs of prophylaxis were borne by the hospital.
who had contact with the patient’s bed linens. All affected staff members continued to work despite symptoms and presented for evaluation only after being identified as contacts. Contact tracing also identified 9 patient contacts, 2 of whom were diagnosed with scabies, both from the internal medicine unit. One of these patients was a discharged roommate of the index patient who was diagnosed with scabies after readmission to a different unit. The second patient had been admitted into the same bed as the index patient after the index patient’s discharge. This patient was diagnosed by her family physician.
Management of a scabies outbreak Confirmation of nosocomial transmission of scabies within the hospital led to the declaration of an outbreak on both affected units. The local public health authorities were notified, and additional control measures were implemented (Table 1). The identification of staff members who worked while symptomatic for prolonged periods further complicated contact tracing efforts, and it was felt that ongoing contact tracing would be too labor-intensive and possibly inaccurate. Contact tracing was abandoned on the outbreak units in favor of simultaneous mass prophylaxis of all patients and staff members. Simultaneous mass prophylaxis was logistically challenging, but was implemented without ward closure. Details of this implementation are presented in Table 1. No additional patient cases were identified after the initiation of mass prophylaxis. A single staff member inadvertently omitted from the mass prophylaxis developed scabies. When no additional
cases occurred for 6 weeks after this case, the OMT declared the outbreak over. No additional patient or staff cases were identified during 2010. A similar approach was also used successfully at facility A, with no additional cases occurring after mass prophylaxis there. In addition to patients and staff members included in the mass prophylaxis, 285 additional patients were identified as potential contacts, including 208 discharged and 77 transferred patients. Family physicians and receiving facilities were notified. One of the transferred patients was subsequently identified as having scabies. This patient had not been directly exposed to the index patient, but had been admitted to the internal medicine unit and discharged before implementation of mass prophylaxis. He most likely acquired scabies from one of the symptomatic staff members.
Outcomes In total, 6 staff members and 3 patients developed scabies as a result of nosocomial transmission at St. Michael’s Hospital. An additional 12 staff members developed scabies at facility A. Two of the 9 patients with direct contact with the index case developed scabies, for an estimated attack rate of 22%. This rate is an underestimate, however, given that all 7 asymptomatic contacts received prophylaxis or had been discharged by the time they were identified. Five staff members who cared directly for the index patient or had direct contact with the patient’s bed linens and clothing developed scabies, but an accurate denominator of staff with direct contact could not be determined. A total of 385 patients required
454
A. Khan et al. / American Journal of Infection Control 40 (2012) 451-5
prophylaxis (9 direct contacts, 276 possible contacts, and 100 requiring mass prophylaxis), as did 597 staff members. The outbreak lasted 9 weeks, although all symptomatic cases related to St. Michael’s Hospital were identified within a 3-week period. A crude estimate of the cost of the outbreak suggested a total cost of approximately $20,000, of which the largest single cost was 5% permethrin (w$16,000), followed by extra nursing and environmental services staffing (w$2000) during mass prophylaxis. DISCUSSION In this report, we describe a scabies outbreak that started in an acute care hospital after the admission of a patient with unrecognized crusted scabies on 3 separate occasions. The outbreak resulted in 9 cases of scabies transmission at St. Michael’s Hospital and 12 cases at an affiliated rehabilitation hospital. The onset of this outbreak is typical of previously reported acute care scabies outbreaks. In almost all cases, outbreaks are triggered by the admission of a patient with unrecognized crusted scabies.3-5 The index patient is typically immunocompromised or elderly and debilitated and is initially misdiagnosed with another dermatologic condition, often requiring treatment with corticosteroids.2-5 The correct diagnosis is established either when a lack of response to corticosteroid therapy is recognized or when health care workers begin to manifest scabies.5 Despite similarities in the factors predisposing to hospital scabies outbreaks, considerable variation exists in outbreak size and duration. A review of hospital scabies outbreaks reported between 1971 and 1990 found that the mean number of secondary cases was 46 (range, 8-300).4 In a more recent review of outbreaks reported between 1983 and 2003, the mean number of secondary cases was 18 (range, 3-82), and the mean duration of outbreak was 14.5 weeks (range, 4-52 weeks).5 The variation in outbreak size suggests that there may be important differences in the efficacy of the control strategies used; the decrease in the number of cases between these 2 reviews suggests that outbreak control strategies have improved over time. Interestingly, a similar outbreak was reported from St. Michael’s Hospital 20 years ago.6 An 86-year-old woman with chronic renal failure and a 2-month history of diffuse pruritic rash was admitted. A skin biopsy was interpreted as leukocytoclastic vasculitis, and she was treated with prednisone and cyclophosphamide. Only after staff began to develop scabies 6 weeks into the patient’s hospitalization was a diagnosis of crusted scabies made. Although both the earlier outbreak and the present outbreak involved prolonged unprotected exposure of staff members to a case of crusted scabies, management strategies differed substantially between the 2 outbreaks. In the earlier outbreak, the affected ward was closed for 4 days, and contact tracing with prophylaxis of contacts was the primary intervention. By the time the outbreak was controlled, 45 staff members and 32 patients had developed scabies, and 500 staff members and 228 patients had received prophylaxis.6 Household transmission and recurrence of scabies occurred in 7 staff members and 5 patients, and the outbreak had lasted for 4 months. A crude estimate of the cost of the outbreak was $100,000 in 1992 Canadian dollars.6 In our recent outbreak, the total number of patients and staff affected and the duration of the outbreak were significantly reduced, and ward closure was avoided; furthermore, there were no recurrences, and crude costs were substantially lower (w$20,000 in 2010 Canadian dollars). We believe that simultaneous mass prophylaxis was the key strategy that accounted for more rapid outbreak control. Although anecdotal, this conclusion is supported by the literature. In early reports, the primary control strategy used for hospital scabies outbreaks was simply treatment of symptomatic patients
and staff members.9-14 This approach often resulted in large and protracted outbreaks. In one outbreak, treatment of symptomatic patients failed to interrupt transmission until the affected ward was closed for 21 days.11 In another, cases continued to present for 20 days after implementation of the control strategy.12 In a more recent outbreak where prophylaxis was not used due to limited hospital resources, 28 of 32 staff members developed scabies.15 Based on these experiences, interventions for hospital scabies outbreaks in the 1980s and 1990s typically included contact tracing with prophylaxis of patients or staff members who had direct contact with the index case or secondary cases. In many outbreaks, this approach was considered successful16-19; however, in 2 reports, cases continued to present for 1-2 weeks after initiation of prophylaxis,16,17 and in another report, new scabies cases were detected in staff members for 6 months after the outbreak was declared over.18 In the one expediently controlled outbreak that relied on contact tracing, the index patient was identified and placed on barrier precautions within 36 hours of admission, significantly limiting the extent of exposure.19 The long incubation period of scabies and the potential for transmission before symptoms become apparent makes accurate contact tracing difficult and suggests that mass prophylaxis may be more efficient. The potential for reinfestation of staff members after treatment or prophylaxis from unrecognized cases provides the rationale for simultaneous mass prophylaxis. Comparison of outcomes from the 2 St. Michael’s Hospital outbreaks supports this conclusion, as do other reports describing failures of the contact tracing approach. In one outbreak, widespread scabies in laundry staff members exposed to contaminated linens led to multiple secondary and tertiary cases across an entire hospital. Transmission was interrupted only by simultaneous mass prophylaxis of all hospital staff.20 In a recent outbreak involving a patient with crusted scabies admitted to an ICU for 7 weeks before diagnosis, contact tracing and prophylaxis failed to control the outbreak for 3 months, and control was achieved only after simultaneous mass prophylaxis of all ICU staff.7 In another outbreak, a patient with undiagnosed crusted scabies was admitted to an AIDS ward for 24 days without precautions.8 A subsequent questionnaire identified 113 health care workers and 82 patients with symptoms consistent with scabies. Mass prophylaxis of all health care workers on the AIDS ward terminated the outbreak despite its large initial scope. The single most important step in preventing or limiting a hospital scabies outbreak is to rapidly identify, isolate and treat patients with crusted scabies. To achieve this aim, health care workers need ongoing education on the epidemiology and clinical features of both classic and crusted scabies. This is particularly true for health care workers who deal regularly with immunocompromised, elderly, and debilitated patients. Prompt initiation of barrier precautions for patients with unexplained rash is also important.21 Despite these measures, patients with crusted scabies will continue to be misdiagnosed. When a patient with unrecognized crusted scabies has been admitted without appropriate infection control precautions, or when a cluster of staff members with suspected scabies are identified, a multidisciplinary OMT should be assembled to investigate and manage a potential scabies outbreak. The OMT should promptly identify and manage the index case, conduct surveillance for secondary cases, initiate contact tracing with prophylaxis for exposed patients and staff, and develop an effective internal communications strategy designed to encourage staff to report symptoms while minimizing the anxiety provoked by scabies outbreaks. Family members of symptomatic cases should be treated as well. This approach may be sufficient if the index case is identified promptly, the extent of potential exposure is modest, and no secondary cases occur; however, when extended unprotected exposure of patients and staff members to a case of crusted scabies has occurred, or when secondary cases have already occurred, we
A. Khan et al. / American Journal of Infection Control 40 (2012) 451-5
believe that simultaneous mass prophylaxis of the involved ward(s) is the most effective strategy to rapidly interrupt transmission, minimize disruptions in clinical care, and reduce staff anxiety. Hospital scabies outbreaks can be stressful for patients, health care workers, and hospital staff members charged with controlling them. When large exposures and/or multiple secondary cases occur, simultaneous mass prophylaxis is the best approach to rapidly and efficiently control such an outbreak, and can be achieved without ward closure. We hope that our experience can help other facilities prepare for and deal with the unpleasant reality of a scabies outbreak with minimal stress, expense, or interruption in the provision of high-quality medical care. References
8.
9. 10. 11. 12. 13. 14. 15. 16.
1. Chosidow O. Clinical practices. Scabies. N Engl J Med 2006;354:1718-27. 2. Hicks MI, Elston DM. Scabies. Dermatol Ther 2009;22:279-92. 3. Bouvresse S, Chosidow O. Scabies in healthcare settings. Curr Opin Infect Dis 2010;23:111-8. 4. Lettau LA. Nosocomial transmission and infection control aspects of parasitic and ectoparasitic diseases, part III: ectoparasites/summary and conclusions. Infect Control Hosp Epidemiol 1991;12:179-85. 5. Vorou R, Remoudaki HD, Maltezou HC. Nosocomial scabies. J Hosp Infect 2007; 65:9-14. 6. Bannatyne RM, Patterson TA, Wells BA, MacMillan SA, Cunningham GA, Tellier R. Hospital outbreak traced to a case of Norwegian scabies. Can J Infect Control 1992;7:111-3. 7. Buehlmann M, Beltraminelli H, Strub C, Bircher A, Jordan X, Battegay M, et al. Scabies outbreak in an intensive care unit with 1,659 exposed individuals: key
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factors for controlling the outbreak. Infect Control Hosp Epidemiol 2009;30: 354-60. Obasanjo OO, Wu P, Conlon M, Karanfil LV, Pryor P, Molar G, et al. An outbreak of scabies in a teaching hospital: lessons learned. Infect Control Hosp Epidemiol 2001;22:13-8. Leads from the MMWR. Patient-source scabies among hospital personneldPennsylvania. JAMA 1983;250:1817-8. Bernstein B, Mihan R. Hospital epidemic of scabies [letter]. J Pediatr 1973;83: 1086-7. Carslaw JW, Dobson RM, Hood AJ, Taylor RN. Mites in the environment of cases of Norwegian scabies. Br J Dermatol 1975;92:333-7. Gooch JJ, Strasius SR, Beamer B, Reiter MD, Gene PD, Correll GW. Nosocomial outbreak of scabies. Arch Dermatol 1978;114:897-8. Haydon Jr JR, Caplan RM. Epidemic scabies. Arch Dermatol 1971;103:168-73. Lee W. An unusual scabies epidemic in an urban hospital. Am J Infect Control 2011;17:95 [abstract]. Danchaivijitr S, Suthipinittharm P, Srihapol N. An outbreak of Norwegian scabies in a surgical ward. J Med Assoc Thai 1995;78(Suppl 2):99-S101. Clark J, Friesen DL, Williams WA. Management of an outbreak of Norwegian scabies. Am J Infection Control 1992;20:217-20. Hsueh PR, Lin BH, Hwang CC, Hsieh BL, Liu JC, Lin M. Nosocomial outbreak of scabies. J Formos Med Assoc 1992;91:228-32. Lerche NW, Currier RW, Juranek DD, Baer W, Dubay NJ. Atypical crusted “Norwegian” scabies: report of nosocomial transmission in a community hospital and an approach to control. Cutis 1983;31:637-42. Zafar AB, Beidas SO, Sylvester LK. Control of transmission of Norwegian scabies. Infect Control Hosp Epidemiol 2002;23:278-9. Pasternak J, Richtmann R, Ganme AP, Rodrigues EA, Silva FB, Hirata ML, et al. Scabies epidemic: price and prejudice. Infect Control Hosp Epidemiol 1994;15: 540-2. Achtari JL, Erard P, Gueissaz F, Malinverni R. An outbreak of scabies: a forgotten parasitic disease still present in Switzerland. Swiss Med Wkly 2007;137:695-9.
Contents lists available at ScienceDirect
American Journal of Infection Control
American Journal of Infection Control
journal homepage: www.ajicjournal.org
Major article
Rapid control of a scabies outbreak at a tertiary care hospital without ward closure Anjum Khan MBBS, MSc, CIC a, Sharon O’Grady ART, BAS, CIC b, Matthew Paul Muller MD, PhD, FRCPC a, c, * a
Infection Prevention and Control Service, St. Michael’s Hospital, Toronto, ON, Canada Infection Control, Bridgepoint Health, Toronto, ON, Canada c Department of Medicine, University of Toronto, Toronto, ON, Canada b
Key Words: Infection control Sarcoptes scabei Ectoparasitic infestation Mass prophylaxis
Background: Although scabies outbreaks in hospitals are frequent, the optimal approach to management of these outbreaks has not yet been defined. We describe a hospital scabies outbreak that was successfully controlled without ward closure. Methods: An outbreak of scabies at a teaching hospital and subsequent control measures were investigated. Outcomes included the number of cases affecting patients and staff, number of patients and staff requiring prophylaxis, duration of the outbreak, and cost of the outbreak. Outcomes were compared with those in a similar outbreak occurring at the same hospital 20 years earlier and with other published descriptions of hospital scabies outbreaks. Results: In January 2010, a patient who had undergone renal transplantation was admitted 3 times to St. Michael’s Hospital, but a diagnosis of scabies was not considered until the final admission. Widespread exposure of patients and staff on 2 wards prompted the establishment of an outbreak management team. Initial interventions focused on isolation and treatment of the index case and on contact tracing to identify and treat secondary cases and to offer prophylaxis to direct contacts. Five symptomatic staff members and 2 patient cases were quickly identified, an outbreak was declared, and mass simultaneous prophylaxis was initiated on the 2 involved wards. A single case occurred 2 weeks after the mass prophylaxis program in a staff member who had not received the prophylaxis. Six weeks after the onset of symptoms, the end of the outbreak was declared. No additional cases have been reported up to the time of publication. The total cost of the outbreak was $20,000. Conclusions: Early recognition of crusted scabies is essential to prevent outbreaks. Once an outbreak occurs, prompt control of the index patient and rapid tracing of contacts to identify secondary cases are necessary. When prolonged exposure to a case of crusted scabies results in multiple secondary cases, institution of simultaneous mass prophylaxis is the most efficient strategy for terminating the outbreak and can be implemented without ward closure. Copyright Ó 2012 by the Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.
Scabies is an endemic skin infestation caused by the mite Sarcoptes scabei var hominis.1,2 In most individuals, classic scabies causes intense pruritus and an erythematous papular rash in a characteristic distribution; however, in immunocompromised, neurologically impaired, or debilitated elderly patients, scabies may present with diffuse scaly plaques, thickened nails, and no pruritus.1,2 This form of scabies, called crusted scabies, is associated with a significantly higher burden of mites than classic scabies.2 Whereas transmission from patients with classic scabies results from prolonged skin-to-skin contact, transmission from a patient with crusted
* Address correspondence to Matthew Paul Muller, MD, PhD, FRCPC, St. Michael’s Hospital, Infection Prevention and Control Service, 30 Bond Street, Toronto, ON M5B 1W8, Canada. E-mail address: [email protected] (M.P. Muller). Conflict of interest: None to report.
scabies can result from transient direct contact or from indirect contact with bedding, clothing, or other contaminated fomites.2 Scabies has been associated with outbreaks in institutional settings, including acute care medical facilities. Outbreaks in acute care settings often follow the admission of a patient with unrecognized crusted scabies.3-5 Large numbers of patients and staff are often exposed before crusted scabies is diagnosed, and such outbreaks can be widespread, prolonged, and difficult to control.3,6-8 Scabies outbreaks often provoke significant anxiety among staff and can result in ward closure, disruption of medical services, and significant excess costs.3,5-8 Despite the challenges posed by scabies outbreaks in acute care facilities, there remains no consensus on the optimal approach to controlling outbreaks in this setting. We report a scabies outbreak in an acute care hospital, with spread to a second rehabilitation facility, that was rapidly controlled without ward closure through the rapid implementation
0196-6553/$36.00 - Copyright Ó 2012 by the Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved. doi:10.1016/j.ajic.2011.05.014
452
A. Khan et al. / American Journal of Infection Control 40 (2012) 451-5 Outbreak declared and mass prophylaxis initiated 22 Feb
10 9 8 7 6 5 4 3 2 1 0
Outbreak declared over 22 April
Index case diagnosed with crusted scabies 19 Feb
3-9 Jan
10-16 jan 17-23 jan 24-30 Jan 31-6 Feb 7-13 Feb 14-20 Feb 21-27 Feb 28 Feb-6 7-13 mar 14-20 Mar 21-27 Mar 28-3 Apr 4-10 Apr 11-17 Apr 18-24 Apr
Mar Fig 1. Epidemic curve. The black bar represents staff cases in the rehabilitation facility; the gray bar, staff cases in the acute care facility; the checked bar, patient cases in the acute care facility. The dashed line represents admission of the index patient to the acute care facility.
of effective infection control measures, including simultaneous mass prophylaxis. METHODS We describe an outbreak of scabies that occurred at St. Michael’s Hospital, a 500-bed acute care teaching hospital in Toronto, Canada, and an affiliated complex care hospital (designated facility A). Here we describe all of the interventions used to control transmission of scabies during the outbreak in sufficient detail to be reproducible and useful to other acute care facilities confronted with a scabies exposure or outbreak. In accordance with the case definition used during the outbreak, patients and staff members were considered to have scabies if they developed severe pruritus and a characteristic rash after admission to or employment on any of the affected units during or after January 2010. For patients with an atypical clinical presentation, a positive skin scraping or skin biopsy was required for confirmation; however, given the limited sensitivity of skin scrapings, cases with characteristic clinical findings but negative skin scrapings were included. The decision of whether or not to perform skin scraping was left to the discretion of the treating physician. Outcomes assessed include the duration of the outbreak, the number of affected patients and staff, and the number of patients and staff requiring prophylaxis. We compared these outcomes with those from a similar outbreak at St. Michael’s Hospital occurring 20 years earlier.6 Although we did not conduct a formal cost analysis, we evaluated the differences in cost between the current and previously reported outbreak using the same categories in both outbreaks (ie, medication costs, ward closure, absenteeism, overtime, increased length of hospital stay, and mailing costs). RESULTS Initial case presentation In January 2010, a 68-year-old female undergoing renal transplantation was admitted to the St. Michael’s Hospital internal medicine inpatient unit with right-sided deep venous thrombosis and urinary tract infection. Her immunosuppressive regimen consisted of prednisone 20 mg daily and tacrolimus 3 mg twice daily. A diffuse maculopapular rash noted on admission was treated with 0.1% betamethasone cream. The day before discharge, the patient complained of pruritus and was given an antihistamine. After 2 weeks in the hospital, she was discharged to facility A (Fig 1).
Six days after discharge, the patient was readmitted to the hospital with recurrent urinary tract infection initially to our internal medicine unit and later to our nephrology ward. On admission, she complained of pruritus, and examination revealed thickened dystrophic nails with hyperkeratosis on the elbows and feet. During hospitalization, she developed diffuse erythroderma and progressive hyperkeratosis on her hands, elbows, legs, and feet. Dermatology was consulted, and a skin biopsy was performed. The pathology was interpreted as nondiagnostic but consistent with a resolving drug eruption. The patient was treated with 1% hydrocortisone cream and 3% salicyclic acid topically. Ten days later, she was transferred back to facility A. Within 1 day of the patient’s transfer (and 16 days after her initial admission to facility A), staff members at facility A began manifesting symptoms consistent with scabies. Within 6 days of the transfer, 12 staff members were diagnosed with scabies. After 1 week at facility A, the patient was readmitted to St. Michael’s Hospital with confusion and a diffuse rash. Because of the scabies outbreak at facility A, the patient was placed on precautions on arrival in the emergency department, and her rash was reevaluated. A repeat skin biopsy confirmed the diagnosis of crusted scabies. Treatment with ivermectin was initiated, but the patient died of septic shock secondary to a perforated duodenal ulcer before the completion of treatment. Initial investigation and management of scabies exposure The identification of this patient with crusted scabies admitted twice for a total of 24 days with no precautions prompted the immediate creation of an outbreak management team (OMT) with representation from all involved units, infection control, employee health, environmental services, pharmacy, public relations, and administration. The OMT immediately initiated contact tracing to identify and offer prophylaxis to all patients and staff who had direct exposure to the index patient or her immediate environment, including mobile staff, such as phlebotomists and radiology technicians; notification of facilities and family physicians of exposed patients already discharged or transferred; and development of a communication strategy to inform staff about the situation and encourage staff members with pruritic rash to present to the hospital’s employee health department for assessment (Table 1). Five staff members with scabies, 4 from the internal medicine unit and 1 from the nephrology unit, were rapidly identified via contact tracing. All identified staff members were nurses who cared for the index patient except for one environmental service worker
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Table 1 Measures implemented to control scabies after identification of exposure or nosocomial transmission Goal
Intervention
Measures implemented after recognition of exposure Management of index Private room with barrier precautions (ie, gown, patient with crusted gloves) plus hand hygiene on room entry and exit scabies Initiation of treatment Environmental cleaning Handling of contaminated linens
Contact tracing
Identification of patient contacts of the index patient Identifications of staff contacts of the index patient Management of contacts
Management of family members Internal communication
Communication to staff members in affected areas
Comment Hand hygiene with soap/water is preferred on room exit; ensure no gap between gowning and gloving before room entry. Booties not recommended. Treatment with ivermectin (200 mg/kg orally) and 5% permethrin. Terminal (ie, “isolation room”) cleaning for rooms recently occupied by the index patient, and standard daily cleaning of the index patient’s room. Linens were bagged and transported to the laundry. Staff in the laundry use gowns/gloves routinely. Linens were washed in hot water. No additional precautions were used. Roommates from all admissions, and patients admitted directly into a bed previously occupied by the index case. All staff members who had direct contact with the index patient or the index patient’s bedside environment, including mobile staff. All contacts were evaluated for symptomatic scabies. All contacts received 5% permethrin cream as treatment or prophylaxis. Discharged or transferred patient contacts were notified by phone and/or mail. Treatment with 5% permethrin was provided free of charge to all family members of symptomatic patients or staff members. Staff members were informed of the situation, instructed to contact employee health if symptomatic (and to not work), and informed that prophylaxis would be provided without charge.
Additional measures added after nosocomial transmission identified and outbreak declared External communication Notification of local public health authorities Internal communications Communication to all staff members Hospital staff were informed of the situation. Signs informing visitors and staff members of required procedures were posted on outbreak units. Staff was reassured that a control strategy was in place and that staff members would receive prophylaxis. Administration of prophylaxis with 5% permethrin Over a 12-hour period all patients without medical contraindications were treated, Simultaneous mass prophylaxis of patients to all patients on the outbreak units patient clothing and bedding was changed, and rooms were cleaned. Health care workers used gowns and gloves for all patient care during this 12-hour period. Simultaneous mass Administration of prophylaxis with 5% permethrin Staff prophylaxis was initiated at the same time as patient prophylaxis. Staff members prophylaxis of staff to all staff members working on the outbreak were given 5% permethrin at the end of their shifts to self-treat overnight. Staff units members not working that day were called at home and asked to self-treat before their next shift. A staff member who could not be contacted before her shift was required to use barrier precautions for patient care and to receive prophylaxis after her shift. All but one staff member received prophylaxis within 4 days, and no staff member refused treatment. The costs of prophylaxis were borne by the hospital.
who had contact with the patient’s bed linens. All affected staff members continued to work despite symptoms and presented for evaluation only after being identified as contacts. Contact tracing also identified 9 patient contacts, 2 of whom were diagnosed with scabies, both from the internal medicine unit. One of these patients was a discharged roommate of the index patient who was diagnosed with scabies after readmission to a different unit. The second patient had been admitted into the same bed as the index patient after the index patient’s discharge. This patient was diagnosed by her family physician.
Management of a scabies outbreak Confirmation of nosocomial transmission of scabies within the hospital led to the declaration of an outbreak on both affected units. The local public health authorities were notified, and additional control measures were implemented (Table 1). The identification of staff members who worked while symptomatic for prolonged periods further complicated contact tracing efforts, and it was felt that ongoing contact tracing would be too labor-intensive and possibly inaccurate. Contact tracing was abandoned on the outbreak units in favor of simultaneous mass prophylaxis of all patients and staff members. Simultaneous mass prophylaxis was logistically challenging, but was implemented without ward closure. Details of this implementation are presented in Table 1. No additional patient cases were identified after the initiation of mass prophylaxis. A single staff member inadvertently omitted from the mass prophylaxis developed scabies. When no additional
cases occurred for 6 weeks after this case, the OMT declared the outbreak over. No additional patient or staff cases were identified during 2010. A similar approach was also used successfully at facility A, with no additional cases occurring after mass prophylaxis there. In addition to patients and staff members included in the mass prophylaxis, 285 additional patients were identified as potential contacts, including 208 discharged and 77 transferred patients. Family physicians and receiving facilities were notified. One of the transferred patients was subsequently identified as having scabies. This patient had not been directly exposed to the index patient, but had been admitted to the internal medicine unit and discharged before implementation of mass prophylaxis. He most likely acquired scabies from one of the symptomatic staff members.
Outcomes In total, 6 staff members and 3 patients developed scabies as a result of nosocomial transmission at St. Michael’s Hospital. An additional 12 staff members developed scabies at facility A. Two of the 9 patients with direct contact with the index case developed scabies, for an estimated attack rate of 22%. This rate is an underestimate, however, given that all 7 asymptomatic contacts received prophylaxis or had been discharged by the time they were identified. Five staff members who cared directly for the index patient or had direct contact with the patient’s bed linens and clothing developed scabies, but an accurate denominator of staff with direct contact could not be determined. A total of 385 patients required
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prophylaxis (9 direct contacts, 276 possible contacts, and 100 requiring mass prophylaxis), as did 597 staff members. The outbreak lasted 9 weeks, although all symptomatic cases related to St. Michael’s Hospital were identified within a 3-week period. A crude estimate of the cost of the outbreak suggested a total cost of approximately $20,000, of which the largest single cost was 5% permethrin (w$16,000), followed by extra nursing and environmental services staffing (w$2000) during mass prophylaxis. DISCUSSION In this report, we describe a scabies outbreak that started in an acute care hospital after the admission of a patient with unrecognized crusted scabies on 3 separate occasions. The outbreak resulted in 9 cases of scabies transmission at St. Michael’s Hospital and 12 cases at an affiliated rehabilitation hospital. The onset of this outbreak is typical of previously reported acute care scabies outbreaks. In almost all cases, outbreaks are triggered by the admission of a patient with unrecognized crusted scabies.3-5 The index patient is typically immunocompromised or elderly and debilitated and is initially misdiagnosed with another dermatologic condition, often requiring treatment with corticosteroids.2-5 The correct diagnosis is established either when a lack of response to corticosteroid therapy is recognized or when health care workers begin to manifest scabies.5 Despite similarities in the factors predisposing to hospital scabies outbreaks, considerable variation exists in outbreak size and duration. A review of hospital scabies outbreaks reported between 1971 and 1990 found that the mean number of secondary cases was 46 (range, 8-300).4 In a more recent review of outbreaks reported between 1983 and 2003, the mean number of secondary cases was 18 (range, 3-82), and the mean duration of outbreak was 14.5 weeks (range, 4-52 weeks).5 The variation in outbreak size suggests that there may be important differences in the efficacy of the control strategies used; the decrease in the number of cases between these 2 reviews suggests that outbreak control strategies have improved over time. Interestingly, a similar outbreak was reported from St. Michael’s Hospital 20 years ago.6 An 86-year-old woman with chronic renal failure and a 2-month history of diffuse pruritic rash was admitted. A skin biopsy was interpreted as leukocytoclastic vasculitis, and she was treated with prednisone and cyclophosphamide. Only after staff began to develop scabies 6 weeks into the patient’s hospitalization was a diagnosis of crusted scabies made. Although both the earlier outbreak and the present outbreak involved prolonged unprotected exposure of staff members to a case of crusted scabies, management strategies differed substantially between the 2 outbreaks. In the earlier outbreak, the affected ward was closed for 4 days, and contact tracing with prophylaxis of contacts was the primary intervention. By the time the outbreak was controlled, 45 staff members and 32 patients had developed scabies, and 500 staff members and 228 patients had received prophylaxis.6 Household transmission and recurrence of scabies occurred in 7 staff members and 5 patients, and the outbreak had lasted for 4 months. A crude estimate of the cost of the outbreak was $100,000 in 1992 Canadian dollars.6 In our recent outbreak, the total number of patients and staff affected and the duration of the outbreak were significantly reduced, and ward closure was avoided; furthermore, there were no recurrences, and crude costs were substantially lower (w$20,000 in 2010 Canadian dollars). We believe that simultaneous mass prophylaxis was the key strategy that accounted for more rapid outbreak control. Although anecdotal, this conclusion is supported by the literature. In early reports, the primary control strategy used for hospital scabies outbreaks was simply treatment of symptomatic patients
and staff members.9-14 This approach often resulted in large and protracted outbreaks. In one outbreak, treatment of symptomatic patients failed to interrupt transmission until the affected ward was closed for 21 days.11 In another, cases continued to present for 20 days after implementation of the control strategy.12 In a more recent outbreak where prophylaxis was not used due to limited hospital resources, 28 of 32 staff members developed scabies.15 Based on these experiences, interventions for hospital scabies outbreaks in the 1980s and 1990s typically included contact tracing with prophylaxis of patients or staff members who had direct contact with the index case or secondary cases. In many outbreaks, this approach was considered successful16-19; however, in 2 reports, cases continued to present for 1-2 weeks after initiation of prophylaxis,16,17 and in another report, new scabies cases were detected in staff members for 6 months after the outbreak was declared over.18 In the one expediently controlled outbreak that relied on contact tracing, the index patient was identified and placed on barrier precautions within 36 hours of admission, significantly limiting the extent of exposure.19 The long incubation period of scabies and the potential for transmission before symptoms become apparent makes accurate contact tracing difficult and suggests that mass prophylaxis may be more efficient. The potential for reinfestation of staff members after treatment or prophylaxis from unrecognized cases provides the rationale for simultaneous mass prophylaxis. Comparison of outcomes from the 2 St. Michael’s Hospital outbreaks supports this conclusion, as do other reports describing failures of the contact tracing approach. In one outbreak, widespread scabies in laundry staff members exposed to contaminated linens led to multiple secondary and tertiary cases across an entire hospital. Transmission was interrupted only by simultaneous mass prophylaxis of all hospital staff.20 In a recent outbreak involving a patient with crusted scabies admitted to an ICU for 7 weeks before diagnosis, contact tracing and prophylaxis failed to control the outbreak for 3 months, and control was achieved only after simultaneous mass prophylaxis of all ICU staff.7 In another outbreak, a patient with undiagnosed crusted scabies was admitted to an AIDS ward for 24 days without precautions.8 A subsequent questionnaire identified 113 health care workers and 82 patients with symptoms consistent with scabies. Mass prophylaxis of all health care workers on the AIDS ward terminated the outbreak despite its large initial scope. The single most important step in preventing or limiting a hospital scabies outbreak is to rapidly identify, isolate and treat patients with crusted scabies. To achieve this aim, health care workers need ongoing education on the epidemiology and clinical features of both classic and crusted scabies. This is particularly true for health care workers who deal regularly with immunocompromised, elderly, and debilitated patients. Prompt initiation of barrier precautions for patients with unexplained rash is also important.21 Despite these measures, patients with crusted scabies will continue to be misdiagnosed. When a patient with unrecognized crusted scabies has been admitted without appropriate infection control precautions, or when a cluster of staff members with suspected scabies are identified, a multidisciplinary OMT should be assembled to investigate and manage a potential scabies outbreak. The OMT should promptly identify and manage the index case, conduct surveillance for secondary cases, initiate contact tracing with prophylaxis for exposed patients and staff, and develop an effective internal communications strategy designed to encourage staff to report symptoms while minimizing the anxiety provoked by scabies outbreaks. Family members of symptomatic cases should be treated as well. This approach may be sufficient if the index case is identified promptly, the extent of potential exposure is modest, and no secondary cases occur; however, when extended unprotected exposure of patients and staff members to a case of crusted scabies has occurred, or when secondary cases have already occurred, we
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believe that simultaneous mass prophylaxis of the involved ward(s) is the most effective strategy to rapidly interrupt transmission, minimize disruptions in clinical care, and reduce staff anxiety. Hospital scabies outbreaks can be stressful for patients, health care workers, and hospital staff members charged with controlling them. When large exposures and/or multiple secondary cases occur, simultaneous mass prophylaxis is the best approach to rapidly and efficiently control such an outbreak, and can be achieved without ward closure. We hope that our experience can help other facilities prepare for and deal with the unpleasant reality of a scabies outbreak with minimal stress, expense, or interruption in the provision of high-quality medical care. References
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