Outbreak of scabies in Norwegian nursing homes and home care patients: control and prevention

Over a period of five months (October 1998-February 1999), an outbreak of scabies affected 19 persons associated with a nursing home in Oslo, Norway. Scabies was diagnosed in 13 patients; six long-term patients, five short-term patients also cared for at home, and two home care patients associated with the same institution. Six healthcare workers who had assisted with infected patients in their own homes were also diagnosed with scabies. Two separate index cases were found. Both had had pruritus for several months, diagnosed as eczema, and were repeatedly treated at dermatology outpatient clinics before the diagnosis was made. Both index cases were cared for at home and in the nursing home (short-term). Repeated treatments with permethrin were tried before effective treatment with benzyl benzoate. Altogether 370 persons (patients, staff, relatives) were treated. In June-July 1999, scabies was diagnosed in two other nursing homes; six patients or staff, and 156 persons were treated. Patients with scabies were contact isolated and disinfection and cleaning was performed. Simultaneous treatment and washing or disinfection of clothing, bedding and environment of all potentially affected individuals is imperative to control an outbreak of scabies.

Management of endemic outbreaks of scabies with allethrin, permethrin, and ivermectin

BACKGROUND

At three residences for the elderly, recurrent scabies infestations became out of control. Due to the failure of repeated, nonsynchronized therapeutic efforts with conventional external anti-scabies treatments, an eradication program had to be developed. We describe a protocol for the management of outbreaks of scabies.

METHODS

According to the clinical examination and microscopically identified mites, all individuals of the population (IOP: patients, staff, and family members) were divided into two groups: (a) healthy and infested IOP; and (b) cases with crusted scabies. The first group was treated simultaneously once with external scabicides (allethrin or permethrin). All others were hospitalized and treated either with systemic ivermectin or with the latter in combination with permethrin.

RESULTS

In 252 IOP living in three residences for the elderly, clinical signs of scabies were reported in 91.5%, 78.5%, and 15.4% of the patients (age 55-97 years; mean, 80.5 years), 54.1%, 32.9%, and 16.6% of staff members, and in 7%, 3%, and 0% of family members. The infested IOP showed crusted scabies (index cases) in 5.3%, 5.0%, and 1.7%, common scabies in 43.1%, 36.7%, and 7.1%, and postscabiotic dermatitis in 10.3%, 7.6%, and 3.5%. In 99.2% of the synchronously treated IOP in group (a) (n = 240), the conventional treatment with permethrin cream 5% or allethrin spray was effective. Group (b) (n=12) received ivermectin (12 mg) once (n=5) or twice (n= 7) after an interval of 8 days. One index case received permethrin three times.

CONCLUSIONS

Outbreaks of scabies in populations of elderly people require special management for disease control. Synchronous treatment with external permethrin cream 5% or allethrin spray, including all IOP once, and close control offers a time-saving, cheap, and reliable method. Crusted scabies should be treated by oral administration of ivermectin once or twice after an interval of 8 days. Additional applications of permethrin and mechanical clearing of hyperkeratotic subungual areas shorten the course.

Scabies and pediculosis

Scabies and pediculosis are ubiquitous, contagious, and debilitating parasitic dermatoses. They have been known since antiquity and are distributed worldwide. Clusters of infestation occur-for example, scabies affecting immunocompromised individuals or patients and staff in hospitals and nursing homes for the elderly, and pediculosis affecting schoolchildren or homeless people. Associations with other disorders are common: infections with human T-cell leukaemia/lymphoma virus I (HTLV-I) and HIV are associated with scabies, and trench fever and exanthematous typhus with pediculosis. Specific forms of scabies, including bullous scabies or localised crusted scabies, may be misdiagnosed. Moreover, definitive parasitic diagnosis can be difficult to obtain, and the value of new techniques remains to be confirmed. Difficulties in management have returned scabies and pediculosis to the limelight.

Eradication of porcine sarcoptic mange within a health declared production model

The success of a large-scale eradication programme against sarcoptic mange was evaluated in piglet producing herds belonging to the health class LSO 2000. These farms are monitored to be free from sarcoptic mange, swine enzootic pneumoniae, swine dysentery and progressive atrophic rhinitis. The local veterinarians were instructed to eradicate sarcoptic mange from the herds by 2 ivermectin injections 14 days apart or 3 treatments with phoxim pour-on 6 days apart before the farms were able to join the health class. The study consisted of a questionnaire administered to the farmers, farm visits and follow-ups associated with the regular control of the health class. A questionnaire was sent to all of the 379 accepted farrowing farms. Altogether 323 farmers had initiated an eradication programme at least 7 months before the questionnaire was distributed and 96% of them believed that the mange eradication programme had been successful. In most of the successful herds (90%), the local veterinarian had treated the animals by the recommended methods, and the majority of the farmers (88%) had cleaned and sprayed the pens with insecticides on the days of treatment. Three out of the 7 unsuccessful farms had employed methods other than those recommended. Twenty-five herds were randomly selected for an intensified control. The rubbing index was < or = 0.1 in all herds visited, indicating freedom from mange. Sows or gilts, 15-20 animals per farm, were skin scraped and no Sarcoptes scabiei was found. The same animals were blood sampled and serum antibodies to S. scabiei were measured by an indirect ELISA. All except 1 farm had low optical density (OD) values in most of the samples. The owner of that farm had become uncertain about the mange status of the herd and had recently retreated all animals with acaricides. The number of complaints about mange in the finishing units buying health class feeder pigs was low. The study demonstrates that it is possible to run an eradication programme against sarcoptic mange, in which a large number of farmers together with their veterinarians participate. It is possible to eradicate mange not only at the herd but also at the population level. The ELISA test employed proved to be a possible tool to monitor the efficacy of mange-eradication programmes.

[Effective scabies control system in Moscow]

The analysis using the systems approach, analogue simulation, practical conclusions of the probability theory, mathematical statistical methods, programme-oriented work organization revealed and eliminated a number of neglects that had put bounds to scabies morbidity reduction among Moscovites. In 1998, the number of the foci that dermatovenereological facilities were unaware of substantially showed a 6.9-fold decrease. Therefore, the incidence of scabies reduced by 14.6% in the city in 1998. The paper presents the guidelines developed by the authors, which will ensure that the incidence rates of scabies be 25.07 per 100,000 Moscovites by 2005. It analyzes the scabies epidemiological situation among the homeless and possible measures to promote health in this group of persons.

Epidemiology and control of scabies in an Egyptian village

BACKGROUND

Some studies have addressed the epidemiology of scabies among rural populations in developing countries; however, the epidemiology of scabies among the rural population in Egypt is unknown. We sought to determine the magnitude of scabies infestation in an Egyptian village and to evaluate the control measures after 1 year.

METHODS

This study was carried out on 3147 residents of Mit-Moaned village in Dakahlia govemorate, Egypt. It was a cross-sectional follow-up study where the same individuals examined in round I were re-examined in round III. The two rounds were separated by a period of 1 year, during which infested patients were followed up and new cases were discovered (round II). Patients and their household contacts received treatment with topical permethrin. Patients showing resistance to permethrin received a single oral dose of ivermectin.

RESULTS

In round III, the overall prevalence rate of scabies was reduced from 5.4% in round I to 1.1%. The incidence of new cases among susceptible persons during round II was 1.1%. Scabies was significantly (P < 0.05) more prevalent among families of large size, high crowding index at night, low socioeconomic standards, and those receiving their water supply from a hand pump. Children younger than 10 years showed the highest prevalence.

CONCLUSIONS

Our data provide the first complete picture of the epidemiology of scabies in rural Egypt. The epidemiologic characteristics of the disease should be considered in the design of disease control programs for other villages with scabies epidemics. Our findings revealed that good control was achieved with the following: increased awareness and better case finding, education of the staff at the rural health unit, improved hygiene measures, and massive treatment campaigns using effective drugs such as topical permethrin and oral ivermectin.

Persistent efficacy of doramectin and ivermectin against experimental infestations of Sarcoptes scabiei var. suis in swine

Two studies were performed to compare the persistent efficacy of doramectin and ivermectin in swine experimentally infested with Sarcoptes scabiei var. suis. In the Study 1, 84 pigs were treated with doramectin, ivermectin, or saline solution on Day 0. Pigs were then challenged with mites on Days 0, 7, 14, 21, 28, 35, or 42. Weekly evaluations were performed for 5 weeks following challenge with mites. Weekly evaluations included physical examination for clinical signs of sarcoptic mange and collection of skin scrapings for determination of mite counts. In the Study 2, 80 pigs were treated with doramectin, ivermectin, or saline solution on Day 0, and challenged with mites on Days 3, 6, 9, 12, 15, 18, 21, 24, or 27. Weekly evaluations were performed for 6 weeks after challenge exposure. All negative-control (saline-treated) animals in both studies developed evidence of mite infestation. In the Study 1, doramectin prevented mite infestations 7 days longer than ivermectin. Results from the Study 2 indicated that the persistent efficacy of doramectin was 18 days on the basis of mite recovery. This was twice as long as the persistent efficacy of ivermectin, which was 9 days on the basis of mite recovery.

The efficacy of simplified eradication strategies against sarcoptic mange mite infections in swine herds monitored by an ELISA

Eradication programmes directed against Sarcoptes scabiei var. suis, performed without any disinfection of the environment, were compared to an eradication programme including a simultaneous environmental disinfection. The performance of such programmes would be facilitated considerably if environmental disinfection could be avoided. The trial was conducted in four conventional piglet-producing herds designated A-D. All herds suffered from a subclinical but persistent infection with the sarcoptic mite. Herd A was treated with two injections of ivermectin and simultaneously disinfection of the environment was done. In the other herds, the animals were treated twice (B and C) or three times (D) with acaricides (ivermectin or phoxim) at intervals of 7-12 days without any simultaneous disinfection of the buildings or environment. The results were monitored by attempts to demonstrate the mite by skin scrapings, and by monitoring the levels of serum antibodies to Sarcoptes scabiei by an ELISA. Samples were taken from all adults and from 20% of the piglets aged 10-12 weeks, before initiating the control programmes, every third month during the first year and a final sampling 18 months after the treatments. After treatment, the levels of antibodies continuously decreased. Presumably dead S. scabiei were demonstrated in one sow from two of the herds 3 months after initiating acaricidal treatments. S. scabiei was not demonstrated later, nor from skin scrapings of the piglets. The results obtained demonstrate that it is possible to eradicate sarcoptic mange mites in swine herds with the use of simplified eradication programmes. The success of such programmes may efficiently be monitored by measuring the levels of serum antibodies to S. scabiei.

Washing machine usage in remote aboriginal communities

The use of washing machines was investigated in two remote Aboriginal communities in the Anangu Pitjantjatjara homelands. The aim was to look both at machine reliability and to investigate the health aspect of washing clothes. A total of 39 machines were inspected for wear and component reliability every three months over a one-year period. Of these, 10 machines were monitored in detail for water consumption, hours of use and cycles of operation. The machines monitored were Speed Queen model EA2011 (7 kg washing load) commercial units. The field survey results suggested a high rate of operation of the machines with an average of around 1,100 washing cycles per year (range 150 and 2,300 cycles per year). The results were compared with available figures for the average Australian household. A literature survey, to ascertain the health outcomes relating to washing clothes and bedding, confirmed that washing machines are efficient at removal of bacteria from clothes and bedding but suggested that recontamination of clothing after washing often negated the prior removal. High temperature washing (> 60 degrees C) appeared to be advantageous from a health perspective. With regards to larger organisms, while dust mites and body lice transmission between people would probably be decreased by washing clothes, scabies appeared to be mainly transmitted by body contact and thus transmission would be only marginally decreased by the use of washing machines.

[Re-emergence of Norwegian scabies in our environment]

It is reported this uncommon variety of scabies in Cuban patients that caused an epidemic in its areas of origin. It is stressed the severe prutitus observed among these patients, which is usually mild or is absent. It is recommended the dermatological isolation of these individuals and the adoption of prophylactic measures for the personnel being in direct contact with them.

Evaluation of the therapeutic and protective efficacy of doramectin against psoroptic scabies in cattle

Three studies were conducted to evaluate the therapeutic and protective efficacy of doramectin when given by injection at a dose of 200 micrograms/kg against induced Psoroptes otis infestations of cattle. The first study investigated therapeutic efficacy. Mite infestations were established on 15 test animals held in stanchions by transfer of material from infested donor calves. Test animals were then allotted on the basis of mite counts to a treatment group (10 animals) which received doramectin and a control group (5 animals) which received saline. Skin scrapings were collected for mite counts on the day before treatment and on days 7, 14, 21 and 28 after treatment. Efficacy assessed on the basis of the proportion of animals cured by day 28 was 100%. The second study was designed to determine the duration of protective efficacy. Forty-eight scabies-free heifers were allotted to a treated group of 32 which received doramectin, and a control group of 16 which remained untreated. These treatment groups were each divided into eight subgroups. Commencing on treatment day and continuing at weekly intervals for 7 weeks, a subgroup of animals from each treatment was placed in stanchions and challenged by transfer of material from infested donor calves. Skin scrapings for mite counts were collected 7 and 14 days later. Infestations were successfully established on all untreated control calves. Doramectin prevented the establishment of infestation for three weeks and significantly (P < 0.05) reduced infestation levels for an additional two weeks. The third study established the duration of residual protection conferred by doramectin and ivermectin under contact transmission. Ninety-six scabies-free heifers were divided into two equal treatment groups. Animals in one group received doramectin and animals in the other group received ivermectin at its recommended dose of 200 micrograms/kg by subcutaneous injection. Each treatment group was then divided into eight subgroups of six animals. Commencing on treatment day and continuing at weekly intervals for 7 weeks a subgroup of animals from each treatment was exposed to purposely infested seeder animals for one week. Three animals from each treatment subgroup were then placed in individual stanchions in which grooming was prevented and the other three were placed together in a pen where normal grooming behavior was permitted. Skin scrapings for mite counts were collected at weekly intervals for up to 4 weeks. Doramectin provided complete protection against infestation for five weeks compared to four weeks for ivermectin. These periods were not influenced by grooming behavior.

Using slaughter inspections to evaluate sarcoptic mange infestation of finishing swine

Sarcoptic mange is one of the common swine diseases worldwide. Although mange-free populations can be established with caesarean derived stock, by herd repopulation programmes or by eliminating mange with ivermectin, mange remains prevalent in many countries. Field and experimental studies indicate that hypersensitive mange is detrimental to performance of growing pigs. Typically, producers tolerate mange infestation in their herds and control measures are often haphazard. This tolerance to mange infestation is attributable to the covert nature of the losses (reduced growth rate and feed efficiency without mortality) and to the fact that clinical signs of hypersensitive mange (pruritus) are usually viewed as normal. Lack of tools to evaluate mange severity in pigs and to demonstrate its importance has hindered the efforts of veterinarians to control the disease. Traditionally, veterinarians have used slaughter inspections to assess respiratory diseases such as enzootic pneumonia and atrophic rhinitis. Much of the value of slaughter inspections is as a tool with which veterinarians can educate and motivate their clients to improve disease control measures. The potential for evaluating hypersensitive mange by inspecting slaughtered pigs for lesions of papular dermatitis was recognised some time ago, but quantitative evaluation of the reliability of this approach has been lacking. We have conducted several studies in Australia, the USA, Canada, Europe and Latin America to evaluate associations between Sarcoptes infestation and the severity of papular dermatitis at slaughter, using a simple ordinal scale for classifying carcasses. Our initial field and experimental data in Australia indicated the specificity of localised dermatitis to be in the order of 75-80%, but that the generalised dermatitis was highly specific (> 98%) for mange. Subsequent studies in the US Midwest yielded almost identical results, and indicated that the method may also have some utility for surveillance of mange-free herds. Results from other locations invariably have shown significant associations between dermatitis lesions and mange infestation. Relative to other methods such as skin scrapings and monitoring pruritus, this method is simple and relatively objective, and should be considered for routine inclusion in slaughter inspection protocols.