Long Term Control of Scabies Fifteen Years after an Intensive Treatment Programme

INTRODUCTION

Scabies is a major public health problem in the Pacific and is associated with an increased risk of bacterial skin infections, glomerulonephritis and rheumatic fever. Mass drug administration with ivermectin is a promising strategy for the control of scabies. Mass treatment with ivermectin followed by active case finding was conducted in five communities in the Solomon Islands between 1997 and 2000 and resulted in a significant reduction in the prevalence of both scabies and bacterial skin infections.

METHODS

We conducted a prospective follow-up study of the communities where the original scabies control programme had been undertaken. All residents underwent a standardised examination for the detection of scabies and impetigo.

RESULTS

Three hundred and thirty eight residents were examined, representing 69% of the total population of the five communities. Only 1 case of scabies was found, in an adult who had recently returned from the mainland. The prevalence of active impetigo was 8.8% overall and 12.4% in children aged 12 years or less.

DISCUSSION

We found an extremely low prevalence of scabies 15 years after the cessation of a scabies control programme. The prevalence of impetigo had also declined further since the end of the control programme. Our results suggest that a combination of mass treatment with ivermectin and intensive active case finding may result in long term control of scabies. Larger scale studies and integration with other neglected tropical disease control programmes should be priorities for scabies control efforts.

Immune response induced by candidate Sarcoptes scabiei var. cuniculi DNA vaccine encoding paramyosin in mice

Sarcoptes scabiei is the causal agent of the highly contagious disease sarcoptic mange (scabies) that affects animals and humans worldwide. An increasing number of cases of treatment failure is being reported because of drug resistance. The development of a specific vaccine would be a sustainable option for control of this disease. In this study, we cloned and expressed a S. scabiei gene encoding paramyosin (PAR) and investigated the immune response elicited by DNA encoding PAR in mice. The ability of the DNA vaccine to express antigen in COS-7 cells was confirmed by RT-PCR and IFA. The immune response induced by DNA vaccine was investigated by ELISA, splenocyte proliferation assay, and cytokine production assay. Compared to the pVAX1 control group, the PAR DNA vaccination group showed the higher levels of IgG, IgG1, IgG2a, IgE, IgM, stronger lymphocyte proliferation in mouse spleen, and larger production of IL-2, IL-4, IL-5, and IFN-γ in the supernatant of cultures from splenocytes. These results indicated that the PAR DNA vaccine induced a mixed Th1/Th2 response in mice. In conclusion, our results revealed that the S. scabiei PAR DNA vaccine induced both a humoral and cellular immune response, which would provide basic data for the further study to develop an effective vaccine against sarcoptic mange.

Control of scabies outbreaks in an Italian hospital: an information-centered management strategy

BACKGROUND

Scabies is a dermatologic infestation caused by Sarcoptes scabiei. In industrialized countries, hospitals and other health structures can sometimes be hit. The optimal management of scabies outbreaks still has to be established, mass prophylaxis being one possible option.

METHODS

To identify the optimal approach to containing this re-emerging disease, a local health authority in Lombardy, Northern Italy, carried out an epidemiologic study into 2 scabies epidemics that took place from September to December 2012 in a 600-bed hospital with 26,000 admissions a year.

RESULTS

Over a 3-month period, there were 12 cases of scabies on 4 wards; 43 contacts received prophylaxis. When the first cases were identified, an information campaign involving all hospital personnel was immediately set up. Regular staff meetings were organized, and information leaflets were distributed to patients. Family doctors of discharged patients were informed of the outbreak.

CONCLUSION

A management model based on an information-centered strategy was used in place of mass prophylaxis to deal with scabies epidemics. The success of this approach was confirmed by the managers of the hospital involved (reduced expenditure for prophylactic drugs) and by hospital staff who did not have to deal with potential drug adverse effects.

Interventions for preventing the spread of infestation in close contacts of people with scabies

BACKGROUND

Scabies, caused by Sarcoptes scabiei variety hominis or the human itch mite, is a common parasitic infection. While anyone can become infected, it causes significant morbidity in immunocompromised hosts and it spreads easily between human hosts where there is overcrowding or poor sanitation. The most common symptom reported is itch which is worse at night. As the symptoms are attributed to an allergic reaction to the mite, symptoms usually develop between four to six weeks after primary infection. Therefore, people may be infected for some time prior to developing symptoms. During this time, while asymptomatic, they may spread infection to others they are in close contact with. Consequently, it is usually recommended that when an index case is being treated, others who have been in close contact with the index case should also be provided with treatment.

OBJECTIVES

To assess the effects of prophylactic interventions for contacts of people with scabies to prevent infestation in the contacts.

SEARCH METHODS

We searched electronic databases (Cochrane Occupational Safety and Health Review Group Specialised Register, CENTRAL (The Cochrane Library), MEDLINE (Ovid), Pubmed, EMBASE, LILACS, CINAHL, OpenGrey and WHO ICTRP) up to November 2013.

SELECTION CRITERIA

Randomised controlled trials (RCTs) or cluster RCTs which compared prophylactic interventions which were given to contacts of index cases with scabies infestation. Interventions could be compared to each other, or to placebo or to no treatment. Both drug treatments and non-drug treatments were acceptable.

DATA COLLECTION AND ANALYSIS

Two authors intended to extract dichotomous data (developed infection or did not develop infection) for the effects of interventions and report this as risk ratios with 95% confidence intervals. We intended to report any adverse outcomes similarly.

MAIN RESULTS

We did not include any trials in this review. Out of 29 potentially-relevant studies, we excluded 16 RCTs as the data for the contacts were either not reported or were reported only in combination with the outcomes for the index cases. We excluded a further 11 studies as they were not RCTs. We also excluded one study as not all subjects were examined at baseline and follow-up, and another as it was a case study.

AUTHORS' CONCLUSIONS

The effects of providing prophylactic treatments for contacts of people with scabies to prevent infestation are unknown. We need well-designed RCTs of the use of prophylactic measures to prevent the transmission of scabies conducted with people who had the opportunity for prolonged skin contact with an index case, such as family members, healthcare workers or residential care personnel, within the previous six weeks.

Nurse-led school-based clinics for skin infections and rheumatic fever prevention: results from a pilot study in South Auckland

AIM

To assess the acceptability and feasibility of delivering targeted primary health care in a decile one primary school setting.

METHOD

A pilot public health nurse (PHN)-led clinic was set up in a South Auckland primary school (roll approximately 400). The clinic was based on a previous sore throat clinic model with modifications aimed at improving programme feasibility and effectiveness. The timely identification and treatment of Group A Streptococcal (GAS) throat infections to prevent rheumatic fever (RF), and the prevention and treatment of four skin infections (cellulitis, impetigo, infected eczema and scabies) were the focus. The pilot ran for 15 weeks from April to July 2011. Evaluation included documentation review, key school and healthcare stakeholder interviews and parent questionnaires.

RESULTS

The consent rate was 92.2%. Of a total 722 throat swabs taken from 337 students, 94 were GAS positive. Ninety-eight assessments of skin conditions were completed at which 76 had a skin infection diagnosed, the most common infection being impetigo (n=46). Thirty-one skin infections were diagnosed in the first week of the pilot. PHN workload was high with a total of 539 phone calls, 137 home visits and 51 school-based parent consultations. The approach was highly acceptable to the majority of key stakeholders. Extrapolating pilot costs results in an estimated annual cost of $510 per student for the programme.

CONCLUSION

It is likely to be both acceptable and feasible to take this model of delivering targeted primary health care to school aged children and use it on a larger scale. The complexity of providing this type of service should not be underestimated and it is essential that robust processes are in place to ensure smooth, safe running of such a programme. Long-term outcome evaluation will be vital to assess programme effectiveness.

Management of scabies

Scabies is a common contagious parasitic dermatosis. Transmission of the mite Sarcoptes scabiei var hominis generally occurs by skin-to-skin contact, but with crusted scabies it may also occur through fomites, such as infected clothing or bedding. Diagnosis is usually clinical. A 2010 updated Cochrane review concluded that management of scabies is based on topical scabicides, mainly 5% permethrin. However, oral ivermectin, although not licensed in many countries, may be useful, particularly for patients who cannot tolerate or comply with topical therapy and in institutional scabies epidemics. Patients should also receive detailed information about the infestation to limit further spreading. Cases resulting from close physical or sexual contact, even without symptoms, should be systematically treated. Hygienic measures should be taken after treatment is completed. Patients should be followed to confirm cure, including resolution of itching, which may take up to 4 weeks or longer.

Treatment and control of ectoparasites in sheep

Ectoparasites are a major concern in sheep flocks, wherever sheep are kept. Techniques to control and eradicate lice, ked, or scab have been available since the beginning of the 20th century, but the parasites still exist. Sheep scab (Psoroptes ovis) was eradicated from Australia in the late 1800s, before many of the more effective chemicals were available, and sheep ked is believed to also have been eradicated. Sheep scab has also been eradicated from North America. This article provides an overview of the common ectoparasites of sheep, effective products to control these parasites, and management factors that affect the success of these treatments.

Control strategies for endemic childhood scabies

Human scabies is a major global public health issue, with an estimated 300 million cases per year worldwide. Prevalence rates are particularly high in many third-world regions and within various indigenous communities in developed countries. Infestation with Sarcoptes Scabiei is associated with group-A streptococcal pyoderma which in turn predisposes to rheumatic fever, acute glomerulonephritis and their respective long-term sequelae: rheumatic heart disease and chronic renal insufficiency. The documented difficulties inherent in achieving scabies control within affected communities have motivated us to develop a network-dependent Monte-Carlo model of the scabies contagion, with the dual aims of gaining insight into its dynamics, and in determining the effects of various treatment strategies. Here we show that scabies burden is adversely affected by increases in average network degree, prominent network clustering, and by a person-to-person transmissibility of greater magnitude. We demonstrate that creating a community-specific model allows for the determination of an effective treatment protocol that can satisfy any pre-defined target prevalence. We find frequent low-density treatment protocols are inherently advantageous in comparison with infrequent mass screening and treatment regimes: prevalence rates are lower when compared with protocols that administer the same number of treatments over a given time interval less frequently, and frequent low-density treatment protocols have economic, practical and public acceptance advantages that may facilitate their long-term implementation. This work demonstrates the importance of stochasticity, community structure and the heterogeneity of individuals in influencing the dynamics of the human scabies contagion, and provides a practical method for investigating the outcomes of various intervention strategies.

Prevention, control and treatment of scabies

Scabies is a common, but neglected, skin condition that is becoming increasingly prevalent globally. It causes distress and is frequently regarded as a stigmatising condition, although it can affect anyone of any age or social class. Understanding the epidemiology and life cycle of the mite Sarcoptes scabiei which causes scabies, is the key to effective prevention and control.

Risk factors for scabies among male soldiers in Pakistan: case-control study

Being a preventable disease, good control of scabies can be achieved by identification of risk factors. During the 3-month period February 2006-April 2006 we carried out a case-control study on 200 patients with scabies and 200 controls to identify risk factors for scabies among male soldiers in Pakistan. We identified risk factors for the infestation using logisitic regression analysis. Itching in family/dormitory mates, infrequent bathing, infrequent changing of clothes, low education, sharing beds and being away from the barracks were identified as significant risk factors for scabies, while overcrowding, large family size and sharing of towels and hospitalisation were not.

A persistent problem with scabies in and outside a nursing home in Amsterdam: indications for resistance to lindane and ivermectin

An ongoing outbreak of scabies in and outside a nursing home in Amsterdam is described. Despite standard treatment with lindane and ivermectin, many recurrences were observed which suggested resistance to these drugs. After treatment with 5% permethrine, the patients were finally cured.

[Prediction of the effectiveness of a health care organization system for Muscovites in case of scab]

The present paper gives data on prediction of the number of Muscovites and homeless individuals who suffered from scab in 1998-2005. As of 2005, the difference in the expected and actual number of scab patients among the Muscovites and the homeless was 4.3 and 13% less than the expected values, respectively. At the same time the authors show that over 6 years (2005-2010) the incidence of scab will be able to reduce by 43.5 and 48.7% among the Muscovites and the homeless, respectively. Due to the extensive use of the inexpensive, safe, and most effective drugs medifox and medifox-super to treat scab and disinfect its foci, the efficiency of the treatment and prevention of scab has considerably increased. The above and other measures implemented by a dermatovenereological service and the concerned organizations improved the rating of Moscow: if it occupied the tenth place in the incidence of scab in 1999, then in 2003 it ranked third among the subjects of the Russian Federation.

[Lice, fleas and other beasts]

Bedbugs, lice, fleas and mites are blood-sucking ectoparasites whose bites cause allergic skin reactions. Diagnosis of bites is based on the morphology of the skin eruptions and the pattern of involved skin areas. Confirmation of the diagnosis often requires detection of the causal parasite. The main reservoir for ectoparasites (e.g., bedbugs, fleas, lice and scabies mites) are humans, but animals are also known to harbor ectoparasites (e.g., certain fleas and mites). Fleas, body lice and certain mite larvae in the tropics can transmit infectious diseases, but bedbugs, headlice, pubic lice and scabies mites cannot. Therapy is primarily directed against itching and bacterial superinfections. Pediculosis and scabies are additionally treated with t0pical insecticides. In order to kill freshly hatched larvae, topical treatmentmust be repeated after one week. In the case of pediculosis, people who have come into contact with symptomatic individuals also need to be treated, whereas with scabies, all contact persons must undergo treatment in order toprevent further transmission. Topicalinsecticides, in combination with anti-itch treatment, is usually sufficientto immediately relieve the symptoms and promote permanent healing of the skin lesions.

Safety of benzyl benzoate lotion and permethrin in pregnancy: a retrospective matched cohort study

OBJECTIVE

To assess the safety of benzyl benzoate lotion (BBL) and permethrin, topical treatments for scabies, during pregnancy.

DESIGN

A retrospective controlled cohort study.

POPULATION

Refugee and migrant women attending antenatal clinics (ANC) on the Thai-Burmese border between August 1993 and April 2006.

METHODS

Women treated with either BBL (25%) or permethrin (4%) were identified from a manual search of antenatal records. Each case of scabies was matched with four scabies-free controls for gravidity, age, smoking status, malaria, period of treatment and gestational age at treatment. Conditional Poisson regression was used to estimate risk ratios for outcomes of pregnancy (proportion of abortions, congenital abnormalities, neonatal deaths, stillbirths and premature babies), mean birthweight and estimated median gestational age, for scabies and scabies-free women, independently for BBL and permethrin.

RESULTS

There were no statistically significant differences in pregnancy outcomes between women who were treated with either BBL (n = 444) compared with their matched controls (n = 1,776) or permethrin (n = 196) treated women and their matched controls (n = 784). Overall, only 10.9% (n = 66) of treatments were in the first trimester. Retreatment rates were higher with BBL 16.4%, than permethrin 9.7%, P = 0.038. Scabies was more common during cooler periods.

CONCLUSION

We found no evidence of adverse effects on pregnancy outcome due to topical 25% BBL or 4% permethrin.

Nosocomial scabies

Scabies is a parasitic dermatosis with a worldwide distribution. This infestation affects millions of people annually and may cause large nosocomial outbreaks with considerable morbidity among patients and healthcare workers. Immunocompromised or elderly institutionalized patients admitted with unrecognized crusted scabies are the main source of nosocomial transmission. Factors that facilitate the development of hospital-acquired scabies and nosocomial epidemics are: poor knowledge of scabies epidemiology, unfamiliarity of healthcare workers with atypical presentations, long incubation period, diagnostic delay and incomplete monitoring. Within hospitals, containment of an outbreak relies on the strict implementation of appropriate infection control measures and treatment administration to contacts. It is associated with a considerable working and economic burden.

Recent immunologic considerations regarding the itch and treatment of scabies

Scabies continues to be a major public health problem. Recent findings reveal that these mites produce substances that modulate the host's immune response resulting in the latency period prior to symptoms. In terms of treatment, two cases of ivermectin resistance have come to fore in Australia in patients treated over fifty times with the agent. Additionally, work in the development of vaccination of hosts with antigenic midgut proteins of mites to control ectoparasitic infestations continues.

A scabies outbreak in a further education college in Gloucestershire

Scabies outbreaks in England have been reported in hospitals, long-stay wards, acquired immune deficiency syndrome (AIDS) units and residential homes for the elderly. This paper describes the control of an outbreak in a further education college for persons with learning disabilities. In March 2004, four confirmed cases of scabies were reported among a subset of 108 students and 41 staff members. Staff had considerable physical contact with the students who were housed in five groups of homes, individual homes and support centres. Mass prophylaxis was offered to all staff and students, through 39 general practice surgeries. Challenges overcome were: ensuring complete case ascertainment, accessing of up-to-date information about students and staff, achieving a coordinated approach to treatment, securing informed consent and media management. No further outbreaks have been reported. The college has revised its information request form for new students.

[Sarcoptes scabiei var. suis in a closed pig breeding and fattening herd and control possibilities after treatment]

On an Austrian pig breeding and finishing farm containing 13,000 pigs a mange prevalence of 38.7% according to the results of the skin scraping and 28.2% based on serology was determined. Due to the insufficient treatment (single treatment of the sows using Phoxim [Sebacil pour on]), sustainable control was impossible. That could be confirmed by the high number of mange positive gilts and finishing pigs. Before eradication started the following prevalences of mange could be found: sows 6.74% (skin scrapings), respectively 6.18% (serologically), gilts 18.18% resp 28.67%, finishing pigs 54.35% and 38.58%. The breeding stock for eradication was treated with doramectin (Dectomax) injectable solution and the finishing pigs with Ivomec-praemix, both applied twice. The success of treatment of the different farm units and of different age groups was controlled for the following ten months by combined diagnostic methods. In addition to skin scrapings, serum and colostral samples were carried out using a commercially available ELISA licensed for investigation of blood serum and colostrum. After treatment antibodies in the serum of the sows and gilts and Sarcoptes mites in their skin scrapings were detectable for up to four months after treatment. In serum samples of piglets and colostrum samples antibodies against Sarcoptes mites were detectable up to five months after final treatment. Due to the higher level and longer verifiability of antibodies in blood samples of piglets for five months after treatment and high prevalences their use as a diagnostic tool can be recommended. In contrast the use of colostral samples for routine diagnosis should be investigated more thoroughly. The comparison of the results of different diagnostic methods showed that for reliable mange diagnosis combined methods are recommended.