Serum Zinc Levels and Immune Status of Children with Persistent Diarrhea Following Oral Zinc Supplementation

Background: Persistent diarrhea (PD) is a common disease in childhood worldwide. Clinical studies suggested that zinc supplementation is useful in most PD children. However, the relationship between the zinc and immune status of the PD children has not been reported. Objective: To examine serum zinc levels and immune status in 6 to 24 months old children with PD before and after 120 days of oral zinc supplementation and to evaluate the effects of zinc supplementation on serum zinc levels and immune status in PD children. Methods: A case control study was carried. Fifty-eight children aged 6 to 24 months with PD were enrolled. 58 patients were divided into two groups, zinc group (28 cases) and control group (30 cases). Laboratory investigation of serum zinc levels, Lymphocyte subsets (CD3+%, CD4+%, CD8+% and CD4+/CD8+ ratio) and immunoglobulins (IgG, IgA and IgM) levels was carried out in all these patients once at enrollment and again after 120 days of treatment. Results: Before treatment, the serum zinc concentration was 4.37 ± 1.23 μmol/L in zinc group and 4.42 ± 1.45 μmol/L in control group (P > 0.05). However, after treatment, the serum zinc concentrations in the zinc group were significantly higher (8.81 ± 2.56 μmol/L), as compared to the control group (4.12 ± 1.02 μmol/L) (P < 0.05). Regarding immune status, Lymphocyte subsets CD3+%, CD4+%, CD8+% and CD4+/CD8+ ratio and IgG, IgA and IgM levels of all the children with PD were measured once at enrollment and again after 120 days of treatment. There were no significant differences between the zinc and the control groups in CD3+%, CD4+%, CD8+% and CD4+/CD8+ ratios (P > 0.05) before giving treatment. However, after 120 days of treatment, in the zinc group there was a significant rise in CD4+% (53.60 ± 5.78). The CD4 was significantly higher in the zinc group as compared to the control group (44.73 ± 4.39) (P < 0.05). Besides CD4+%, the CD4+/CD8+ ratio was also found to be higher among zinc group (1.49 ± 0.29) as compared to the control group (1.26 ± 0.18) after treatment (P < 0.05). But there were no statistically significant differences in CD3+% and CD8+% between zinc and control group after treatment (P > 0.05). Regarding immunoglobulins, there were no significant differences between zinc and control group in IgG, IgA and IgM levels (P > 0.05) at the time of enrollment (before treatment). However, after treatment, the mean IgG levels in zinc group and control group were 6.36 ± 0.95 g/l and 5.67 ± 0.74 g/l, respectively, P < 0.05. Similarly, after treatment, IgM levels in the zinc group were found significantly higher (1.58 ± 0.13 g/l), as compared to the control group (1.43 ± 0.20 g/l) (P < 0.05) but no significant differences in IgA levels were evident between the two groups after treatment. Conclusion: Administration of oral zinc supplement improved both serum zinc levels and immune status in children with PD. Zinc supplementation should be administered as adjunctive therapy for PD children.

A novel real-time RT-PCR with TaqM an-MGB probes and its application in detecting BVDV infections in dairy farms

A real-time RT-PCR assay using Taq Man-MGB probes was developed to detect and type the bovine viral diarrhea virus（BVDV） in cattle.Universal primers and Taq Man-MGB probes were designed from the 5′-untranslated region of known pestiviral sequences.Prior to optimizing the assay, c RNAs were transcribed in vitro from the BVDV 1 and BVDV 2 RTPCR products to make standard curves.The detection limit of the assay was 1.72×102 copies for BVDV 1 and 2.14×102copies for BVDV 2.The specificity of the assay evaluated on several BVDV strains including bovine herpesvirus 1（BHV 1）, foot and mouth disease virus（FMDV） and several classical swine fever virus（CSFV） strains showed specific detection of the positive virus over 40 cycles.The assay was highly reproducible with the coefficient of variance ranging from 1.04 to 1.33% for BVDV 1 and from 0.83 to 1.48% for BVDV 2, respectively.Using this method, we tested a total of 2 327 cattle from three dairy farms for the presence of BVDV persistently infected（PI） animals.In this assay, each RT-PCR template contained a mixture of ten samples from different animals.The occurrence rate of PI cattle in three farms ranging from 0.9 to 2.54% could represent partly the PI rates in cattle farm in China.In conclusion, using our real-time PCR assay, we could effectively detect and type BVDV and identify PI cattle in a rapid and cost-effective manner.