Molecular Characterization of Cryptosporidium Species and Giardia duodenalis from Symptomatic Cambodian Children

Background: In a prospective study, 498 single faecal samples from children aged under 16 years attending an outpatient clinic in the Angkor Hospital for Children, northwest Cambodia, were examined for Cryptosporidium oocysts and Giardia cysts using microscopy and molecular assays. Methodology/Principal Findings: Cryptosporidium oocysts were detected in 2.2% (11/498) of samples using microscopy and in 7.7% (38/498) with molecular tests. Giardia duodenalis cysts were detected in 18.9% (94/498) by microscopy and 27.7% (138/498) by molecular tests; 82% of the positive samples (by either method) were from children aged 1–10 years. Cryptosporidium hominis was the most common species of Cryptosporidium, detected in 13 (34.2%) samples, followed by Cryptosporidium meleagridis in 9 (23.7%), Cryptosporidium parvum in 8 (21.1%), Cryptosporidium canis in 5 (13.2%), and Cryptosporidium suis and Cryptosporidium ubiquitum in one sample each. Cryptosporidium hominis and C. parvum positive samples were subtyped by sequencing the GP60 gene: C. hominis IaA16R6 and C. parvum IIeA7G1 were the most abundant subtypes. Giardia duodenalis was typed using a multiplex real-time PCR targeting assemblages A and B. Assemblage B (106; 76.8% of all Giardia positive samples) was most common followed by A (12.3%) and mixed infections (5.1%). Risk factors associated with Cryptosporidium were malnutrition (AOR 9.63, 95% CI 1.67–55.46), chronic medical diagnoses (AOR 4.51, 95% CI 1.79–11.34) and the presence of birds in the household (AOR 2.99, 95% CI 1.16–7.73); specifically C. hominis (p = 0.03) and C. meleagridis (p<0.001) were associated with the presence of birds. The use of soap was protective against Giardia infection (OR 0.74, 95% CI 0.58–0.95). Conclusions/Significance: This is the first report to describe the different Cryptosporidium species and subtypes and Giardia duodenalis assemblages in Cambodian children. The variety of Cryptosporidium species detected indicates both anthroponotic and zoonotic transmission in this population. Interventions to improve sanitation, increase hand washing after defecation and before preparing food and promote drinking boiled water may reduce the burden of these two parasites

Effect of dental treatments on salivary immunoglobulin A of children with and without dental caries: A comparative study

Aim: To evaluate and compare the effect of dental treatment on the salivary immunoglobulin A (IgA) levels of children with and without dental caries. Materials and Methods: The study involved 30 children, among which 15 had caries and the other 15 were without caries. Salivary sample collection was done for all the children before dental treatment, and for the children with caries, the sampling was repeated 3-4 weeks after the dental treatment. The salivary IgA quantitation was done by enzyme-linked immunosorbent assay (ELISA), using Human IgA ELISA Quantitation kit, and the results were statistically analyzed by independent sample "t" test. Results:The salivary IgA level was significantly more in children with caries (13.07 ± 1.55 mg/100 ml) than in caries-free children (11.90 ± 1.58 mg/100 ml) in the pre-treatment phase. The salivary IgA level in children with caries was 13.52 ± 1.68 mg/100 ml in the post-treatment phase and it was not statistically different from the pre-treatment value. Conclusion: Mere quantitation of salivary IgA levels might have no reflection on the functional antibodies involved in caries process, and successful dental treatment alone does not alter the salivary IgA levels, suggesting a multifaceted approach to combat the cariogenic challenge