Development and evaluation of real-time loop-mediated isothermal amplification assay for rapid detection of cystic echinococcosis.

BACKGROUND: Cystic echinococcosis (CE) or hydatidosis, caused by the larval stage of Echinococcus granulosus (EG)-complex, is a neglected parasitic disease of public health importance. The disease is endemic in many African and Mediterranean countries including the Sudan. The objective of the present study was to develop and evaluate a real-time loop-mediated isothermal amplification (LAMP) assay for simple and rapid detection of CE in humans and domestic live stock in Sudan. METHODS: A set of six LAMP primers, designed from the mitochondrial NADH-1 gene of EG cattle strain of genotype 5 (G5), was used as a target for LAMP assay. The assay was performed at a constant temperature (63 °C), with a real-time follow-up using a LightCycler and fluorochrome dye. Following amplification cycles in a simple water bath, LAMP products were observed for color change by naked eye and were visualized under UV light source using agarose gel electrophoresis. RESULTS: The real-time LAMP assay identified a variety of hydatid cysts strains recovered in the Sudan, including Echinococcus canadenses (G6) and Echinococcus ortleppi (G5). Real-time LAMP positive results were detected by the presence of an amplification curve, whereas negative results were indicated by absence of fluorescence detection. Positive LAMP results appeared as a bluish-colored reaction as observed by naked eye, whereas negative LAMP results were observed as purple-colored reaction. The sensitivity studies indicated that the LAMP assay detected as little as a 10 fg of parasite DNA. There was 100 % agreement between results of the LAMP assay and our previously described nested PCR when testing 10-fold serial dilution of DNA extracted from EG-complex hydatid cyst. However, there was no cross-reactivity with other parasites including cysticercus bovis, Fasciola gigantica, and Schistosoma bovis and nucleic acid free samples. CONCLUSION: The developed LAMP assay would be expected to prove highly significant in epidemiological surveys of CE in developing countries or areas of resource-poor settings for both ease of use and cost.

Prenatal psychological distress and 11ß-HSD2 gene expression in human placentas: Systematic review and meta-analysis.

BACKGROUND: The placenta acts as a buffer to regulate the degree of fetal exposure to maternal cortisol through the 11-Beta Hydroxysteroid Dehydrogenase isoenzyme type 2 (11-ß HSD2) enzyme. We conducted a systematic review and meta-analysis to assess the effect of prenatal psychological distress (PPD) on placental 11-ß HSD2 gene expression and explore the related mechanistic pathways involved in fetal neurodevelopment. METHODS: We searched PubMed, Embase, Scopus, APA PsycInfo®, and ProQuest Dissertations for observational studies assessing the association between PPD and 11-ß HSD2 expression in human placentas. Adjusted regression coefficients (ß) and corresponding 95% confidence intervals (CIs) were pooled based on three contextual PPD exposure groups: prenatal depression, anxiety symptoms, and perceived stress. RESULTS: Of 3159 retrieved records, sixteen longitudinal studies involving 1869 participants across seven countries were included. Overall, exposure to PPD disorders showed weak negative associations with the placental 11-ß HSD2 gene expression as follows: prenatal depression (ß -0.01, 95% CI 0.05-0.02, I2=0%), anxiety symptoms (ß -0.02, 95% CI 0.06-0.01, I2=0%), and perceived stress (ß -0.01 95% CI 0.06-0.04, I2=62.8%). Third-trimester PPD exposure was more frequently associated with lower placental 11-ß HSD2 levels. PPD and placental 11-ß HSD2 were associated with changes in cortisol reactivity and the development of adverse health outcomes in mothers and children. Female-offspring were more vulnerable to PPD exposures. CONCLUSION: The study presents evidence of a modest role of prenatal psychological distress in regulating placental 11-ß HSD2 gene expression. Future prospective cohorts utilizing larger sample sizes or advanced statistical methods to enhance the detection of small effect sizes should be planned. Additionally, controlling for key predictors such as the mother's ethnicity, trimester of PPD exposure, mode of delivery, and infant sex is crucial for valid exploration of PPD effects on fetal programming.

First report on circulation of Echinococcus ortleppi in the one humped camel (Camelus dromedaries), Sudan.

BACKGROUND: Echinococcus granulosus (EG) complex, the cause of cystic echinococcosis (CE), infects humans and several other animal species worldwide and hence the disease is of public health importance. Ten genetic variants, or genotypes designated as (G1-G10), are distributed worldwide based on genetic diversity. The objective of this study was to provide some sequence data and phylogeny of EG isolates recovered from the Sudanese one-humped camel (Camelus dromedaries). Fifty samples of hydatid cysts were collected from the one- humped camels (Camelus dromedaries) at Taboul slaughter house, central Sudan. DNAs were extracted from protoscolices and/or associated germinal layers of hydatid cysts using a commercial kit. The mitochondrial NADH dehydrogenase subunit 1 (NADH1) gene and the cytochrome C oxidase subunit 1 (cox1) gene were used as targets for polymerase chain reaction (PCR) amplification. The PCR products were purified and partial sequences were generated. Sequences were further examined by sequence analysis and subsequent phylogeny to compare these sequences to those from known strains of EG circulating globally. RESULTS: The identity of the PCR products were confirmed as NADH1 and cox1 nucleotide sequences using the Basic Local Alignment Search Tool (BLAST) of NCBI (National Center for Biotechnology Information, Bethesda, MD). The phylogenetic analysis showed that 98% (n = 49) of the isolates clustered with Echinococcus canadensis genotype 6 (G6), whereas only one isolate (2%) clustered with Echinococcus ortleppi (G5). CONCLUSIONS: This investigation expands on the existing sequence data generated from EG isolates recovered from camel in the Sudan. The circulation of the cattle genotype (G5) in the one-humped camel is reported here for the first time.