Curr Infect Dis Rep (2014) 16:412 DOI 10.1007/s11908-014-0412-2
HEALTHCARE ASSOCIATED INFECTIONS (G BEARMAN AND D MORGAN, SECTION EDITORS)
Scabies and Bedbugs in Hospital Outbreaks Maroun Sfeir & L. Silvia Munoz-Price
Published online: 5 June 2014 # Springer Science+Business Media New York 2014
Abstract Scabies and bedbugs are two emerging ectoparasitic infections reported in crowded areas, including hospitals. Skin involvement is the main presenting initial manifestation for both infections, and the diagnosis is yet challenging for both. Topical permethrin is considered the first-line therapy for scabies except for crusted scabies which is mainly treated with oral ivermectin. To the contrary, treatment of bedbugs is mainly symptomatic. Avoiding close contact, early diagnosis and treatment of infected persons as well as decontamination of the involved environment play an essential role in controlling outbreaks in healthcare settings.
Introduction Scabies and bedbugs are parasitic infections that have reemerged in the last decades. Personal hygiene and avoidance of close contact among persons play an essential role in controlling these infections. These two conditions constitute infection control problems in healthcare settings. However, not all healthcare professionals are aware of their life cycles, modes of transmission and infection control measures to avoid further spread. Therefore, this review is an update on the pathophysiology of both scabies and bedbugs, their clinical manifestations, diagnosis, treatments and available infection control interventions aiming to control hospital outbreaks.
Keywords Sarcoptes scabiei . Cimex lectularius . Outbreak . Healthcare . Control measures Background
This article is part of the Topical Collection on Healthcare Associated Infections M. Sfeir : L. S. Munoz-Price Department of Medicine, University of Miami Miller School of Medicine/Jackson Memorial Hospital, Miami, FL, USA L. S. Munoz-Price Department of Epidemiology and Public Health, University of Miami Miller School of Medicine/Jackson Memorial Hospital, Miami, FL, USA L. S. Munoz-Price Division of Biostatistics, University of Miami Miller School of Medicine/Jackson Memorial Hospital, Miami, FL, USA L. S. Munoz-Price Department of Surgery, University of Miami Miller School of Medicine/Jackson Memorial Hospital, Miami, FL, USA M. Sfeir (*) 1611 NW 12th Ave, Miami, FL 33136, USA e-mail:
[email protected]
Human scabies is caused by an infestation of the skin by the human itch mite (Sarcoptes scabiei var. hominis). Scabies is an ancient affliction, estimated to have infected humans for the last 2,500 years based on archeological evidence including Egyptian drawings depicting people afflicted with symptoms of scabies [1]. “Scabies” is derived from the Latin word “scabere” for “scratch” [1]. In 1687, the causative parasite was identified by Cestoni and Bonomo using a light microscope [2]. Similarly, bedbugs have cohabitated with humans for thousands of years, as evidenced by the discovery of 3,500-year-old fossilized bedbugs from an Egyptian village [3]. These parasites were prevalent until the 1940s, with an estimated 30 % of homes infested in the US [4•]. After World War 2, bedbug infestations were greatly reduced with the discovery and accepted use of potent pesticides such as dichlorodiphenyltrichloroethane (DDT) [5]. Even though the bedbug population dropped remarkably during the mid-20th century, bedbugs have returned in significant numbers over the past 10 years in North America, Europe, and Australia,
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possibly due to increased insecticide resistance [6], banning the use of DDT in 1972 by the Environmental Protection Agency due to its potential human carcinogen and deleterious effects on wildlife [7•], and increased international travel.
Etiology The scabies mite is an obligate parasite that has eight legs, is whitish-brown in color, and is nearly invisible to the naked eye (Fig. 1a). The symptoms of scabies are caused only by the female mites, which burrow into the skin after being fertilized [8]. The female lays eggs under the skin and continues to tunnel until she dies, usually after a month or two. A person who is infected with scabies typically hosts about 10 to 15 mites at any given time, but may have hundreds or even millions in the case of crusted scabies [8, 9••]. Cimex lectularius, the common bedbug, is red–brown, wingless, oval in shape and approximately 4–5 mm in length (1/4 to 3/8 inches) (Fig. 1b). After feeding, their length can increase by 30–50 % and their weight by 150–200 %. They are nocturnal insects hiding during the day in furniture, mattresses, and behind wallpaper, although they can also travel in clothing and luggage. Bedbugs are blood-sucking Fig. 1 Images of a scabies mite and a bedbug, and clinical appearance of the resulting infections. a A scabies mite. b A common bedbug (Cimex lectularius). c Pimple-like skin rash from scabies. d Crusted rash from Norwegian scabies. e Typical pattern of bedbug bites (the "breakfast, lunch, and dinner pattern")
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ectoparasites that feed at night and are attracted to their victim by warmth and carbon dioxide. They prefer human blood but will also feed on pets, birds, and rodents [3]. Adult bedbugs live for 6 to 12 months and are able to survive a year without feeding [10]. Female bedbugs lay on average five eggs per night; these hatch within a couple of weeks [11•]. Bedbugs are present in both tropical and temperate zones, mainly in dark environments with an availability of warm-blooded hosts. They feed at night when their host is asleep and thus stationary for long periods. Headboards and box springs are frequent hiding places for these ectoparasites, which rarely travel more than 8 feet (2.5 m) to feed [12]. Once a host is located, the bedbug pierces the skin of the victim and injects a chemical that numbs the area before the bite, allowing uninterrupted feeding for up to 5 min [11•].
Transmission Microscopic scabies mites burrow into the upper layer of the skin where they live and lay their eggs. Symptoms most commonly described with scabies are intense itching and a pimple-like skin rash (Fig. 1c). The scabies mite usually spreads by direct prolonged skin-to-skin contact with a person
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who has scabies [8]. Scabies occurs worldwide and affects people of all social classes and races. Scabies can spread rapidly under crowded conditions where close body contact is frequent. Therefore, institutions often affected include nursing homes, extended-care facilities, and prisons [13••, 14••, 15••, 16•, 17•]. Physicians might observe a higher incidence of bedbugs among returning travelers or those exposed to infested furniture imported from abroad [18]. Since the late 1990s, reports of bedbugs have increased in educational institutions, residential areas, and shelters [2]. There has been an increase in the number of cases associated with certain exposures, such as nursing homes, hospitals, office buildings, hotels, schools, college dormitories, and movie theaters [19, 20••]. Although there are no peer-reviewed data on the prevalence of bedbugs in the US, two of the larger pest control companies have released data based on the increase in the number of treatments needed. Some of the major cities dealing with the problem of bedbug infestation are Chicago, New York, Detroit, Cincinnati, and Philadelphia. Additionally, other countries have reported an increased number of outbreaks [8, 21•, 22].
Diagnosis Scabies tends to affect both covered and uncovered skin, and the skin typically shows burrows [8]. A valuable technique to assist in the diagnosis of scabies is the ink burrow test [8, 9••, 10]. This test consists of gently rubbing the scabietic papule with the underside of a fountain pen, covering it with ink. The excess ink is then wiped off with an alcohol-saturated gauze. If a burrow is present the ink will track down it and outline the limits of the canal [8]. Because a lengthy examination may be impractical in the clinical setting, we recommend empiric treatment of patients with pruritus, typical lesions, and a history of either scabies or itching among close contacts [23]. Another diagnostic method is the microscopic identification of mites, eggs, and fecal pellets, which can be performed by suspending skin scrapings in mineral oil [24]. In the hands of most practitioners, skin scrapings have a low sensitivity for scabies (
