Scabies Outbreak: Riyadh Region, 1416 Hijjra

During the last three months of the year 1416 Hijjra, there was a noticeable increase in the reported number of scabies cases in Riyadh including 248 scabies cases (a 10 fold increase) from the Riyadh Medical Complex (RMC) during Dul-Qadda (11/1416).

In response, the Riyadh Health Directorate (RHD) established daily reporting of scabies cases from all Primary Health Care Centers (PHCCs), hospitals, and private clinics. A case of scabies was defined as itching and skin rash in a person who was referred to RMC and was diagnosed as having scabies by the dermatologist in the dermatology clinic in RMC during the first two weeks of Muharam 1/1/1417 to 16/1/1417 Hijjra. Control measures including ensuring the availability of Sulphur and Permithrin cream in hospitals and PHCCs, instruction on application, and health education classes in schools and clinics informing the public that scabies is caused by a mite that is transmitted by direct skin to skin contact were begun.

To assess the relative importance of potential risk factors for transmission, the effect of control measures, and public knowledge of scabies before and after intervention, the Field Epidemiology Training Program conducted a case control study. Newly diagnosed and follow-up case patients were interviewed. Contacts were defined as all household members, including domestic servants who lived with case patients. Three control patients matched by age and district to each scabies case were selected for each case by interviewing successive patients attending the dermatology clinic for reasons other than scabies. Case and control patients were interviewed at the dermatology clinic about personal behavior and household conditions which could be related to scabies transmission.

Within the 15 families with an index case, 28 persons were diagnosed as having scabies. The mean age of the case patients was 15 years. 57% were children under 14 years of age and 68% were students. Female/ male ratio was 1.5:1. There were four children aged 0 to four (14.3%), 12 children aged five to 14 (42.8%) and 12 persons 15 years of age and older (42.9%) affected. Of the 65 families 76.5% were Saudis and 23.5% were non-Saudis. The number of persons per square meter was 1.5 in the houses infested with scabies compared to 1.2 persons per square meter in houses without scabies (P=0.01). The mean number of persons per sleeping room in infested houses was 3.79 whereas in noninfested houses it was 2.68 (P<0.01). Household characteristics such as volume of water used per person, the number of baths per week and the usage of water with soap alone or with sponges, how frequently and the method bed linen was washed and dried, use of a washing machine, laundry or by hand, if clothes were dried indoors or outdoors and the number of persons living in the house were not related to the spread of scabies.

For the first infested person in the family the risk of getting scabies increased with the number of close friends and the degree of contact within the neighborhood. The number of friends or degree of contact in the school did not increase the risk.

We compared cases and contacts and cases and controls for sharing clothes, underwear, and accessories and found none to be statistically significant risk factors.

Both cases and controls had little knowledge about the disease before the outbreak (87.% and 80.4% respectively). They learned about scabies during the last month of 1416 Hijjra. Older family members thought it was an animal disease and did not know if it was treatable. Before the outbreak, 12.5% of case patients and 26.1% of control persons thought scabies was an animal disease, while only 4.2% of the case patients and none of the control persons knew that scabies was treatable. The only significant source of information came from health education sessions in the schools. From the sessions in the schools, 37.5% of case patients and 32.6% of control persons learned that scabies was spread by direct contact and 20.8% of case patients and 26.1% of control persons learned that it was a treatable disease.

These results are consistent with established facts about scabies transmission. Close physical contact; particularly in bedrooms where there is direct physical contact between infested and non-infested persons is probably the most common way scabies is transmitted. It can involve either a sexual partner or skin to skin contact in crowded sleeping quarters. It must be emphasized that non-sexual transmission to other household members, especially infants and children, is common. Any condition that promotes close physical contact within the family or community may result in an increase in incidence. Sharing clothes or linen is of no great importance in transmitting the disease. The life-cycle of the human Sarcoptic mite requires almost constant contact with human skin. Adults and immature mites spend most of their time in burrows in the stratum corneum of the skin. They emerge briefly to start new burrows or to copulate. Two or three eggs are deposited within the burrows each day. Transmission from one person to another is usually accomplished by transfer of an adult mite.

Education is needed, particularly about how close physical contact spreads the disease. Although the occurrence of these outbreaks is disturbing to health officials and the school community scabies is easily treated and controlled via physicians in the PHCCs. Awareness of the disease must be increased and scabies should be suspected, especially in those patients who come repeatedly to the PHCCs with dermatosis who do not respond to treatment or if one or more family members has itching and skin disease. Scabies can be controlled by early recognition and surveillance, asking physicians to diagnose and report scabies cases, and using topical medications such as Sulphur which is applied over the entire body except head and neck for three to five successive nights or Permithrin, applied once nocturnally. The entire household should be treated at the same time. Irrelevant, time consuming control such as laundering sheets and clothes should be avoided. Health providers should focus on relevant control measures and also emphasize the importance of treating all family members at the same time.