Investigation And Molecular Epidemiology Study Of Pathologic Fungi In The Environment Around The Children Infected With Tinea Capitis

Objective:To investigate whether the pathogenic fungi exist in the environment where the children with tinea capitis. To confirm the distinction between the pathogenic fungi in the environment and the pathogenic fungi in the patients using the molecular epidemiology methods. To explore the law of the epidemiology,to provide the prevention and treating evidences for children with tinea capitis.Methods:1.The children with tinea capitis according to clinical diagnosis were choosed as the objects investigated in the study.We conducted the microscopic observation for fungi and fungi culture,and at the same time we collected the goods (hair of childen's relatives,including grandpa, grandma, father, mother, brother,sister and partners,dust from pillow towel,sheet,sofa,floor or carpet,and contact with the pet fur) which the children contacted regularly for fungi culture.2.We compared the positive results in the fungi culture for the fungi in the environment and the pathogenic fungi in the patients. If we can confirm the two fungi from the environment and from the patients are the same one,we amplified the rRNA's ITS area of the pathogenic fungi using the all-purpose primers-ITS1 and ITS4 for the fungi.Then we grouped gene of the pathogen using the single primer-(GACA)4. Subsequently, using the random amplified polymorphic DNA (RAPD) method among pathogenic strains within species to confirm the homology of the pathogen.Results:1.We investigated 91 children with tinea capitis whose average age was 6.4 years ranged from 3 months to 12 years.The results of the fungi culture showed that 44 patients (48.35%) were infected with the Microsporum canis,41(45.05%) for M. ferrugeneum,4(4.40%) for strains of T.mentagrophytes,1(1.10%) for strain of T. rubrum and 1 (1.10%) for M. gypseum.2.Two pathogenic fungi which one was the M. canis and the other was M. ferrugeneum. We detected from the hairs and pillow cover of patients' close relatives;the pathologic fungi from the patients' two partners who have the clinical presentation of tinea capitis were the same with the patients;28 patients(30.77%) got in touch with pets and the same pathologic fungi can be detected from 7 of the 28 patients who got in touch with pets.3. One 760bp specific band can be amplified from 16 Microsporum canis strain got from the hair of the eight patients and environment around the patients using the primer-ITS1 and ITS4. Three specific bands can be amplified from 16 Microsporum canis using the single primer-(GACA)4, and further confirm that the 16 dermatophyte strain were M. canis. 4.The patterns of all M. canis strains was identity in RAPD amplification of rDNA,the strains found in every patinents and related environment was same.Conclusion:1. The children infected with tinea capitis in three to six years, seven to nine years of age for children's incidence peak, explain this age children in the key control object, tinea capitis under 3 years and 10 years old with low incidence of children.2. Microsporum canis is the most common pathogenic fungi of tinea capitis, followed by M. ferrugeneum.3. The results show that children tinea capitis can be directly transmitted by pet and closly contacting partner. So we sugguest that the partners in the prevention children tinea capitis touches pet as less as possible, if had a tinea capitis in close contact with the partners shall be reduced.