Prevalence of pediculosis and its related factors among primary school girls in the north of Iran.

INTRODUCTION: Head lice infestation is one of the main public health problems worldwide and a sanitary, cultural and economic indicator for communities' health. This study aims to estimate the prevalence of head lice infestation among female primary school children in selected districts of Mazandaran Province, Iran. METHODS: In this cross-sectional study, 3033 female school children were recruited using the consensus method. Head lice infestation was defined as visible adult lice, nymph or egg with the naked eye. Data were described by percent frequency and analyzed using the chi-squared test and multivariate logistic regression models. A p-value less than 0.05 was considered significant. RESULTS: Prevalence of head lice infestation among female school children was estimated at 7.9%. The adjusted odds ratios (OR) [95% confidence intervals (CI)] for rural residents, low level educated mothers, family size more than five and not combing their hair were 1.96 (1.41-2.78), 2.46 (1.35-4.49), 2.04 (1.12-3.70) and 3.94 (1.73-8.96), respectively. In addition, considering first grade students as a reference group, the ORs (95% CI) for second and third grades were 1.89 (1.18-3.05) and 1.69 (1.05-2.74), respectively. CONCLUSION: Our study showed that studying in urban schools, low educational level of mothers, grade, family size and no history of regular combing were predictors of head lice infestation.

Prevalence of hepatitis B virus seromarkers in young adults vaccinated at birth; impact on the epidemiology of hepatitis B infection in iran.

BACKGROUND: The epidemiological impact and the duration of protection provided by infant hepatitis B (HB) vaccination are unknown. OBJECTIVES: This study was designed to determine the hepatitis B virus (HBV) infection seromarkers in young adults who have been vaccinated against HBV as the first group of Iranian neonates during 1993 and 1994. PATIENTS AND METHODS: We recruited 510 young adults with a history of complete HB vaccination at birth. HBV seromarkers (HB surface antigen (HBs Ag), antibody against HBs Ag (Anti-HBs), and antibody against HB core antigen (Anti-HBc) were measured using ELISA method. Anti-HBs titers ≥ 10 IU/L were considered protective and titers more than 300 IU/L were indicative of a natural boosting. Positive results for Anti-HBc and HBs Ag were considered as breakthrough infection and possible vaccine failure, respectively. The history of acute symptomatic clinical hepatitis was also investigated. RESULTS: Anti-HBs seropositivity rate was detected in 224 of 510 [95% CI: 39-47] young adults. Breakthrough infection (positive sera for Anti-HBc without chronic infection) was observed in 18 [95% CI: 2.5-3.5] subjects. There were neither HBs Ag positive results nor symptomatic hepatitis cases. CONCLUSIONS: The study results indicated that the neonatal HBV immunization induced a long-term protection against HBV and was very efficacious in reducing chronic HBV infection rate in vaccinated young adults in Iran.

Bordetella pertussis IgG and IgA antibodies seroprevalence among 1-35 y-old population: the role of subclinical pertussis infection.

OBJECTIVE: To determine age-dependent pertussis specific IgG and IgA antibodies seroprevalence in apparently healthy subjects. METHODS: A total of 595 healthy 1-35-y-old individuals divided into 5 different age groups were selected from Sari district. Antipertussis IgG and IgA antibodies levels were measured quantitatively by ELISA method. Positive sera for IgA and also IgG titer ≥150 were considered for recent pertussis infection. RESULTS: High seroprevelence levels (72% and 71%) were observed among preschool (<7 y) children. After decreasing the seroprevelence rates significally to lowest level (54.4%) among school aged (7-11 y), the rates increased again to the highest levels of 60% and 73% at adulthood (P = 0.03 and P = 0.003). In total, 1.55% of study subjects were IgA positive, and 5.7% showed high IgG titers. CONCLUSIONS: The present study reveals, vaccine induced immunity has decreased among school-aged children and natural pertussis infection is common among adolescent and young adults. Also, asymptomatic/sub-clinical recent pertussis infection was prevalent among studied population. These findings necessitate developing new strategies to reduce and control pertussis infection in Iran.

Measles-mumps-rubella revaccination; 18 months vs. 4-6 years of age: potential impacts of schedule changes.

OBJECTIVE: The policy of administering the second dose of measles-mumps-rubella (MMR) vaccine (MMR(2)) has recently changed in Iran, at age 1.5 years instead of 4-6 years previously. The effects of such a change on the immune status of the individual are evaluated in this study. METHODS: Totally 249 and 228 children aged 18 months and 4- to 6-year-olds, respectively, with a documented receipt of primary MMR vaccine at the age of ≥ 1 year were enrolled. Before, and 4-6 weeks after MMR(2) administration, anti-MMR IgG antibody levels were measured using ELISA method. IgM antibody levels were also assessed in measles-rubella seronegative children that responded to MMR(2). Collected data for each component from both age groups were compared by using Fischer's exact probability and chi-square tests. RESULTS: Before revaccination, measles seroimmunity rate was similar between the two groups, but rates to mumps and rubella were significantly higher in younger children-measles: 74 vs. 78.3%; mumps: 82.3 vs. 68.4% and rubella: 75% vs. 67%, respectively. After administration of MMR(2), all seroimmune subjects were IgG boosted. Except for rubella, older seronegative children showed significantly higher seroconvertion rate to MMR(2) and seroprevalence rates increased in vaccinees--measles: 98.2 vs. 94%, mumps: 97 vs. 94.4% and rubella: 87 vs. 92.4%, respectively. Only few measles-rubella seronegative children showed IgM response to MMR(2). CONCLUSION: This study showed that the majority of younger children were susceptible to MMR infection before revaccination. Earlier age policy provides more protection against MMR in preschool-aged children. Rubella strain seems to be less potent than reported.