Scabies outbreaks in nursing homes for the elderly: recognition, treatment options and control of reinfestation

Recent advances in understanding and treating scabies

Scabies is an infestation of the skin caused by the mite Sarcoptes scabiei. In 2017, scabies was recognised by the World Health Organisation as a disease of public importance and was consequently added to the list of neglected tropical diseases. An estimated 200 million people currently have scabies worldwide. Scabies is endemic in many developing countries, with the highest prevalence being in hot, humid climates such as the Pacific and Latin American regions. Scabies causes a host immune response which is intensely itchy. Scratching of the lesions can lead to secondary bacterial infections of the skin, such as impetigo, most commonly caused by Streptococcus pyogenes or Staphylococcus aureus. This can have fatal consequences, such as septicaemia, glomerulonephritis, and rheumatic heart disease. Advances over the past 5 years indicate that mass drug administration is an effective strategy to treat scabies. This review will outline advances in the mite biology, epidemiological understanding, diagnosis, and treatment of scabies.

Molecular epidemiology of a fatal sarcoptic mange epidemic in endangered San Joaquin kit foxes (Vulpes macrotis mutica)

Background

In 2013, sarcoptic mange, caused by Sarcoptes scabiei mites, precipitated a catastrophic decline of the formerly stable urban population of endangered San Joaquin kit foxes (Vulpes macrotis mutica) in Bakersfield, California, USA. In 2019, a smaller sarcoptic mange outbreak affected kit foxes 58 km southwest of Bakersfield in the town of Taft, California. To determine whether the Taft outbreak could have occurred as spillover from the Bakersfield outbreak and whether epidemic control efforts must involve not only kit foxes but also sympatric dogs (Canis lupus familiaris), coyotes (Canis latrans), and red foxes (Vulpes vulpes), we evaluated genotypes and gene flow among mites collected from each host species.

Methods

We used 10 Sarcoptes microsatellite markers (SARM) to perform molecular typing of 445 S. scabiei mites collected from skin scrapings from twenty-two infested kit foxes, two dogs, five coyotes, and five red foxes from Bakersfield, Taft, and other nearby cities.

Results

We identified 60 alleles across all SARM loci; kit fox- and red fox-derived mites were relatively monomorphic, while genetic variability was greatest in Bakersfield coyote- and dog-derived mites. AMOVA analysis documented distinct mite populations unique to hosts, with an overall F_ST of 0.467. The lowest F_ST (i.e. closest genetic relationship, F_ST = 0.038) was between Bakersfield and Taft kit fox-derived mites while the largest genetic difference was between Ventura coyote- and Taft kit fox-derived mites (F_ST = 0.843).

Conclusions

These results confirm the close relationship between the Taft and Bakersfield outbreaks. Although a spillover event likely initiated the kit fox mange outbreak, mite transmission is now primarily kit fox-to-kit fox. Therefore, any large-scale population level intervention should focus on treating kit foxes within the city.

A nosocomial scabies outbreak originating from immunocompromised transplant patients in Turkey: Upholstery as a possible cause

BACKGROUND

Inpatients with crusted scabies represent an important source of nosocomial transmission with consequent outbreaks among patients and healthcare workers. This study aimed to report the course of an institutional scabies outbreak, which progressed with infestation of immunosuppressed transplant patients, health care workers, and caregivers.

METHODS

Patients diagnosed with scabies in a nosocomial outbreak in a 200-bed, tertiary hospital were included. Following a diagnosis of scabies in the index patient, strict contact isolation measures were implemented. During the outbreak, a root cause analysis (RCA) was carried out by an infection prevention and control team.

RESULTS

Forty-two individuals were affected (7 patients, 25 health care workers, and 10 family members of the patients) during the outbreak consisting of three attacks. Index case was a multiple myeloma patient who received hematopoietic stem cell transplantation and presented with crusted scabies. A RCA suggested that upholstery could serve as a means of reservoir. All upholstery of the sofa and armchairs in patient rooms as well as in lounge areas were replaced by wipeable leather material. After the 19-week course of the outbreak, no additional cases of scabies have been observed until now.

CONCLUSION

A high index of suspicion should be maintained, particularly in immunocompromised patients, in order to achieve rapid diagnosis of scabies and to implement institutional infection control measures. It should also be borne in mind that the transmission may occur through direct contact as well as fomites, such as upholstery.

Epidemiologic Trends and Seasonality of Scabies in South Korea, 2010-2017

Scabies is a parasitic skin infection with intense itching. Scabies infection seriously impairs quality of life, while outbreaks in medical institutions cause financial losses. This study aimed to present the annual and seasonal trend of prevalence of scabies in the national population. Scabies cases were extracted from National Health Insurance Service database and its epidemiologic characteristics were assessed. To analyze the seasonality of scabies occurrence, temperature and humidity were included in the model as weather factors, and the per capita gross national income index was adjusted. The annual prevalence by age group was 0.56-0.69 per 1,000 persons until the age of 40 years and peaked at 3.0-4.1 per 1,000 persons in the age group over 80 years. The number of women diagnosed with scabies has been consistently higher compared to that of men since 2010. Mean number of cases diagnosed as scabies was lowest in spring, approximately 4,000 cases, when the average temperature was less than 5°C at 2 months prior, whereas more than 6,000 scabies cases occurred in autumn when temperatures exceeded 25°C at 2 months prior. This study presents the epidemiological characteristics and seasonality of all cases nationwide over 8 years and will help to establish control policies.

Study of pruritus vulvae in geriatric age group in tertiary hospital

BACKGROUND

According to the World Health Organization criteria, geriatric population is people above 60 years of age. In this phase of life, a woman has already gone through menopause and its associated emotional, physical, and hormonal changes. These changes are due to gradual loss of estrogen that comes with menopause which results in dramatic changes in the appearance of vulva and vagina. With age, skin of vulva becomes thin, loses elasticity, and moisture so that the patient starts feeling burning and itchy sensation. The normal acidic pH changes to basic which alters the flora and makes the person prone to other bacterial infections. Apart from infections, there are many other dermatological and nondermatological causes of vulvar itching in this age group such as eczema, contact dermatitis, lichen planus (LP), lichen sclerosus atrophicans, lichen simplex chronicus (LSC), prolapse, incontinence, and carcinoma. The aim is to diagnose the causes of pruritus vulvae in the geriatric age group to decrease the misery of these patients.

METHODS

We selected 40 consecutive females of age group ranging from 60 to 75 years coming to skin OPD with the complaint of pruritus of vulvar region over a period of 1 year. Clinical examination, complete blood count, fasting blood sugar, wet mount, pap smear, and skin biopsy were done in every case.

RESULTS

Out of the forty patients who were included in this study, 17 (42.5%) were diagnosed as a case of LSC and 11 (27.5%) patients had atrophic vaginitis. Three (7.5%) patients presented with tinea. Three (7.5%) cases were clinically diagnosed as scabies. Another 2 (5%) cases were diagnosed as LP and Candida was seen in other 2 (5%) cases. 1 (2.5%) case was diagnosed as bacillary vaginosis and 1 (2.5%) patient was of lichen sclerosus.

CONCLUSION

Pruritus vulvae of geriatric age group are of diverse etiology, therefore, treatment based on precise diagnosis is of prime importance.

A scabies outbreak in a diabetic and collagen disease ward: Management and prevention

Scabies is an infection caused by Sarcoptes scabiei. In developed countries, scabies remains an important public health problem in hospitals and care facilities among elderly or immunocompromised patients. There are a number of medical providers who have not experienced scabies and there has been confusion surrounding its management and prevention. Therefore, the aim of the present study was to identify the optimal approach for the management and prevention of scabies. A scabies outbreak occurred between June 2014 and October 2014 in the Toho University School of Medicine, Omori Hospital (Tokyo, Japan), and the current study investigates factors concerning the outbreak, such as disease recognition, diagnostic strategy, medical staff experience and correspondence after the outbreak occurred. Six patients were newly diagnosed with scabies including patients, medical staff and family of the medical staff. An infection control committee was implemented and required a follow-up survey of 181 people (144 patients and 37 medical staff). It took ~4 months to resolve the outbreak. Scabies is highly infectious, and sufficient knowledge is required to care for the patients and prevent the infection of healthy people. In this example, the spread of infection was controlled by prompt action.

Development of Conventional and Real-Time Quantitative PCR Assays for Diagnosis and Monitoring of Scabies

Scabies remains the most prevalent, endemic, and neglected ectoparasitic infestation globally and can cause institutional outbreaks. The sensitivity of routine microscopy for demonstration of Sarcoptes scabiei mites or eggs in skin scrapings is only about 50%. Except for three studies using conventional or two-tube nested PCR on a small number of cases, no systematic study has been performed to improve the laboratory diagnosis of this important infection. We developed a conventional and a real-time quantitative PCR (qPCR) assay based on the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene of S. scabiei. The cox1 gene is relatively well conserved, with its sequence having no high levels of similarity to the sequences of other human skin mites, pathogenic zoonotic mites, or common house dust mite species. This mitochondrial gene is also present in large quantities in arthropod cells, potentially improving the sensitivity of a PCR-based assay. In our study, both assays were specific and were more sensitive than microscopy in diagnosing scabies, with positive and negative predictive values of 100%. The S. scabiei DNA copy number in the microscopy-positive specimens was significantly higher than that in the microscopy-negative specimens (median S. scabiei DNA copy number, 3.604 versus 2.457 log10 copies per reaction; P = 0.0213). In the patient with crusted scabies, the qPCR assay performed on lesional skin swabs instead of scrapings revealed that the parasite DNA load took about 2 weeks to become negative after treatment. The utility of using lesional skin swabs as an alternative sample for diagnosis of scabies by PCR should be further evaluated.

Scabies Outbreak in an Intensive Care Unit with 1,659 Exposed Individuals—Key Factors for Controlling the Outbreak

Objective.

To investigate a large outbreak of scabies in an intensive care unit of a university hospital and an affiliated rehabilitation center, and to establish effective control measures to prevent further transmission.

Design.

Outbreak investigation.

Setting.

The intensive care unit of a 750-bed university hospital and an affiliated 92-bed rehabilitation center.

Methods.

All exposed individuals were screened by a senior staff dermatologist. Scabies was diagnosed on the basis of (1) identification of mites by skin scraping, (2) identification of mites by dermoscopy, or (3) clinical examination of patients without history of prior treatment for typical burrows. During a follow-up period of 6 months, the attack rate was calculated as the number of symptomatic individuals divided by the total number of exposed individuals.

Interventions.

All exposed healthcare workers (HCWs) and their household members underwent preemptive treatment. Initially, the most effective registered drug in Switzerland (ie, topical lindane) was prescribed, but this prescribption was switched to topical permethrin or systemic ivermectin as a result of the progression of the outbreak. Individuals with any signs or symptoms of scabies underwent dermatological examination.

Results.

Within 7 months, 19 cases of scabies were diagnosed, 6 in children with a mean age of 3.1 years after exposure to the index patient with HIV and crusted scabies. A total of 1,640 exposed individuals underwent preemptive treatment. The highest attack rate of 26%–32% was observed among HCWs involved in the care of the index patient. A too-restricted definition of individuals at risk, non-compliance with treatment, and the limited effectiveness of lindane likely led to treatment failure, relapse, and reinfestation within families.

Conclusions.

Crusted scabies resulted in high attack rates among HCWs and household contacts. Timely institution of hygienic precautions with close monitoring and widespread, simultaneous scabicide treatment of all exposed individuals are essential for control of an outbreak.

Scabies in the nursing home

Scabies infection is antediluvian and ubiquitous both in developing and developed countries, yet often neglected. Scabies has a predilection to infect vulnerable subsets of population in crowding conditions, typically applicable to residents in the nursing home. The mite incites a unique immunological response from human hosts. Scabies does not manifest as a singular skin condition and may present atypically in older adults, the majority of nursing home residents, where delay has deleterious consequences. Further, pruritus or itching, the hallmark of scabies infection, is a common complaint from a variety of causes among older adults. Hence, the diagnosis is often delayed or missed. There are several pharmacological treatment options; long-term care practitioners need to understand the characteristics of each agent before selection. Even more relevant is the importance of nonpharmacological aspects of management, crucial in the success of averting spread or outbreaks in long-term care settings.

Scabies outbreaks in residential care homes: factors associated with late recognition, burden and impact. A mixed methods study in England

Scabies is an important public health problem in residential care homes. Delayed diagnosis contributes to outbreaks, which may be prolonged and difficult to control. We investigated factors influencing outbreak recognition, diagnosis and treatment, and staff experiences of outbreak control, identifying areas for intervention. We carried out a semi-structured survey of managers, affected residents and staff of seven care homes reporting suspected scabies outbreaks in southern England over a 6-month period. Attack rates ranged from 2% to 50%, and most cases had dementia (37/39, 95%). Cases were diagnosed clinically by GPs (59%) or home staff (41%), none by dermatologists. Most outbreaks were attributable to avoidably late diagnosis of the index case. Participants reported considerable challenges in managing scabies outbreaks, including late diagnosis and recognition of outbreaks; logistically difficult mass treatment; distressing treatment processes and high costs. This study demonstrates the need for improved support for care homes in detecting and managing these outbreaks.

The efficacy of topical ivermectin versus malation 0.5% lotion for the treatment of scabies

Objective: There are different medications for the treatment of scabies but the treatment of choice is still controversial. This study aimed at comparing the efficacy of topical ivermectin versus malation 0.5% lotion for the treatment of scabies. Methods: In total, 340 patients with scabies were enrolled, and randomized into two groups: the first group received 1% ivermectin applied topically to the affected skin and the second group received topical malation 0.5% lotion and were told to apply this twice with 1 week interval. Treatment was evaluated at intervals of 2 and 4 weeks, and if there was treatment failure at the 2-week follow-up, treatment was repeated. Results: Two application of topical ivermectin provided a cure rate of 67.6% at the 2-week follow-up, which increased to 85.2% at the 4-week follow-up after repeating the treatment. Treatment with two applications of malation 0.5% lotion was effective in 44.1% of patients at the 2-week follow-up, which increased to 67.6% at the 4-week follow-up after this treatment was repeated. Conclusion:Two application of ivermectin was as effective as single applications of malation 0.5% lotion at the 2-week follow-up. After repeating the treatment, ivermectin was superior to malation 0.5% lotion at the 4-week follow up.

Common infections in nursing homes: a review of current issues and challenges

Over 1.5 million people live in 16,000 nursing homes in the USA and experience an average of 2 million infections a year. Infections have been associated with high rates of morbidity and mortality, rehospitalization, extended hospital stay and substantial healthcare expenses. Emerging infections and antibiotic-resistant organisms in an institutional environment where there is substantial antimicrobial overuse and the population is older, frailer and sicker, create unique challenges for infection control. This review discusses the common infections, challenges, and a framework for a practical infection prevention program.

Risk factors for recurrence of scabies: a retrospective study of scabies patients in a long-term care hospital

A considerable number of patients suffer recurrence of scabies. To elucidate risk factors for recurrence of scabies, we compared patients who experienced scabies recurrence and those who suffered scabies only once. We conducted a retrospective review of medical records of all scabies patients in a long-term care hospital for the elderly (300 beds; six wards) for a period of 42 months to determine frequency of scabies onsets, underlying diseases, history of treatment, and demographic data such as age and sex. One hundred and forty-eight patients and five hospital staff members suffered scabies during the 42-month study period. All staff members and 98 patients had no recurrence, while 50 patients experienced at least one recurrence of scabies. The cumulative number of scabies diagnoses was 228. The rates of scabies onset and recurrence were considerably different among wards. The dementia unit showed the highest rate of onset and recurrence. In addition to frequent exposure to infectious sources, problematic behavior, such as lying in other patients beds, might cause the high recurrence rate in dementia units. Higher serum total lymphocyte count and topical use of γ-benzene hexachloride were associated with lower risk of scabies recurrence. Recurrence of scabies is not uncommon among elderly patients in institutional settings. Impaired immunity may be a risk factor for recurrence of scabies. Groups with a high onset rate of scabies pose a high likelihood of recurrence. Problematic behavior of demented patients may increase the risk of recurrence. Use of effective topical treatment may effectively prevent recurrence.

Scabies in healthcare settings

PURPOSE OF REVIEW

In industrialized countries, epidemics of scabies are mainly described within families or in institutions such as healthcare settings. Control of institutional scabies is associated with a considerable working and economic burden, but guidelines for the management are scarce.

RECENT FINDINGS

The prevalence of institutional scabies is probably underestimated. Identified risk factors for institutional scabies outbreaks include the institution type, extensive physical contact with patients and movement of patients, the existence of crusted scabies, a long diagnostic delay and failures in implementation of infection control or treatment plans.Atypical clinical features (hyperinfestation, scabies in the elderly or in children) may be misdiagnosed. Control of institutional scabies outbreaks relies on prompt recognition of the index case, constitution of an outbreak management team, determination of the extent of the outbreak and risk factors for spread, immediate implementation of infection control practices, adequate education of all involved persons, simultaneous treatment of cases and of all exposed individuals and concomitant environmental disinfection. Prolonged surveillance is imperative to eradicate scabies.

SUMMARY

The inclusion of institutionalized patients in randomized controlled trials would be beneficial as present data concerning scabicide effectiveness are obtained from trials that recruited individual participants and do not take into account a global strategy.