Incidence and Risk factors of Blastocystis infection in Orphans at the Babies’ Home, Nonthaburi Province, Thailand
Jitrada Boondit BSc*, Duangnate Pipatsatitpong PhD**, Mathirut Mungthin MD, PhD***, Paanjit Taamasri MSc***, Peerapan Tan-ariya PhD****, Tawee Naaglor MSc***, Saovanee Leelayoova PhD***
Affiliation : * Department of Biology, Faculty of Science, Mahidol University, Bangkok, Thailand ** Department of Medical Technology, Faculty of Allied Health Sciences, Thammasat University, Pathumthani, Thailand *** Department of Parasitology, Phramongkutklao College of Medicine, Bangkok, Thailand **** Department of Microbiology, Faculty of Sciences, Mahidol University, Bangkok, Thailand
Background : Blastocystis infection is one of the most common intestinal protozoan infections reported in Thai population of
all age groups for which epidemiological information is important to understand patterns of transmission for developing
methods of prevention and control for each specific group. The authors aimed to study prevalence, incidence and risk factors
associated with Blastocystis infection in orphans and childcare workers. Additionally, subtypes of Blastocystis were identified.
Material and Method: A retrospective cohort study of Blastocystis sp. was conducted in orphans aged less than 5 years and
their childcare workers at Babies’ Home, Nonthaburi Province, Thailand. A base line survey was conducted in December
2009 and a follow-up survey was conducted in April 2010. A total of 336 and 331 stool samples were collected. Blastocystis
infection was examined using short-term in vitro cultivation in Jones’s medium supplemented with 10% fetal calf serum. To
analyze subtypes of Blastocystis sp., PCR-RFLP of the small subunit ribosomal RNA gene was performed.
Results : The prevalence of Blastocystis infection in December 2009 and April 2010 were 8.1% and 13.3%, respectively. The
incidence rate of Blastocystis infection was 1.6/100 person-months. Subtype analysis of Blastocystis sp. in December 2009
and in April 2010 showed that subtype 3 was the most predominant (76% and 76%), followed by subtype 1 (16% and 20%),
and unidentified subtype (8% and 4%), respectively. Subtype 3 is of human origin, thus person-to-person transmission is
considered a major route of Blastocystis infection in this population.
Conclusion : Person-to-person transmission of Blastocystis infection in orphans living in the same house had been proposed,
thus the prevalence and incidence of Blastocystis infection could be used to reflect the hygienic condition in the orphanage.
Infection prevention and control practice can be effectively implemented.
Keywords : Blastocystis infection, Blastocystis sp., Subtype, Orphans
