A Field Study Using the Polymerase Chain Reaction (Pcr) to Screen for Brugia Microfilariae in Human and Animal Blood

Blood samples from 43 humans and 14 cats positive with Brugia microfilariae were analyzed in a field study in Tanjung Pinang, Indonesia. The study used the polymerase chain reaction (PCR) to compare the sensitivity of radioactive and biotinylated species-specific oligonuleotide probes. The cloning char­acterization of the Hha I repeat DNA family found in filarial parasites of the genus Brugia, and the development of species-specific probes for B.malayi and B.pahangi based on these repeats has been described elsewhere (PNAS USA 83: 797-801); Mol.Biochem. Parasitol. 2$: 163-170). The use of radioisotopes for labelling DNA probes is both expensive and inconvenient. To replace these probes, biotinylated DNA probes have been designed for non- radioactive detection of B.malayi and B.pahangi. These oligonucleotide probes have long tails of biotinylated uridine residues added to their 5\u27 end. As little as 100 pg of Brugia DNA can be detected on dot blot with these probes. Detection of the probes is based on an avidin-alkaline phosphatase colorimetric assay. In order to distinguish between infected from uninfected individuals, it is necessary to detect the amount of DNA in one microfilaria (about 60 pg). The polymerase chain reaction (PCR) is a procedure in which a small amount of DNA can be amplified up to 1 million-fold. A part of each sample in this study was PCR amplified and compared with the unamplified portion using both the radioactive and biotinylated DNA probe. The PCR amplified samples were accurately identified by both the radioactive and biotinylated B.malayi and B.pahangi probes. Even samples with as few as two microfilariae per lOOul of blood were easily detected. The samples that were not PCR amplified were accurately identified after only long exposures (greater than one week) to the radioactive probes. The biotinylated probes, were not sensitive enough for accurate identification of the non-PCR amplified samples. The polymerase chain reaction is, therefore, a promising new tool for enhancing the sensitivity of parasite detection assays based on DNA probes. This will be especially important in designing assay based on non-radioactive DNA probes

Relationship between carotid intima media thickness and helminth infections on Flores Island, Indonesia

Contains fulltext : 117566.pdf (publisher's version ) (Open Access)OBJECTIVE: To examine the association between helminth infections and atherosclerosis. BACKGROUND: Chronic helminth infection, which can lead to poor nutritional status and anti-inflammatory response, might protect against the development of atherosclerosis. METHODS: A cross-sectional study was performed in Flores, Indonesia, an area highly endemic for soil-transmitted helminths (STH). Stool samples from 675 participants aged 18-80 years were collected and screened for Trichuris trichiura by microscopy and for Ascaris lumbricoides, Necator americanus, Ancylostoma duodenale, and Strongyloides stercoralis by qPCR. We collected data on body mass index (BMI), waist to hip ratio (WHR), blood pressure, fasting blood glucose (FBG), lipid, high sensitive C-reactive protein (hs-CRP), total immunoglobulin-E (TIgE) and Escherichia coli lipopolysaccharide stimulated cytokines (tumor necrosis factor and interleukin-10). In a subset of 301 elderly adults (>/=40 years of age) carotid intima media thickness (cIMT) was measured. RESULTS: Participants with any STH infection had lower BMI (kg/m2) (mean difference -0.66, 95%CI [-1.26, -0.06]), WHR (-0.01, [-0.02, -0.00]), total cholesterol (mmol/L) (-0.22, [-0.43, -0.01]) and LDL-cholesterol (mmol/L) (-0.20, [-0.39, -0.00]) than uninfected participants. After additional adjustment for BMI the association between helminth infection and total cholesterol (mean difference -0.17, 95%CI [-0.37, 0.03]) as well as LDL-cholesterol (-0.15, [-0.33, 0.04]) was less pronounced. BMI, WHR, and total cholesterol were negatively associated with number species of helminth co-infections. Participants with high TIgE, an indicator of exposure to helminths, had lower FBG, TC, and HDL. The association between TIgE and TC and HDL remained significant after adjustment with BMI. No clear association was found between STH infection or TIgE and mean cIMT. CONCLUSIONS: This cross-sectional study presents evidence that helminth infections were negatively associated with risk factors for cardiovascular disease, an association at least partially mediated by an effect on BMI. The significance of this finding needs to be determined