Comparing the efficiency of four diagnostic concentration techniques performed on the same group of intestinal parasites

Background: Intestinal parasites are a major public health problem, and their accurate diagnosis is important. The purpose of this study was to evaluate and compare the efficiency of four concentration techniques for the detection of intestinal parasites under laboratory conditions.Methods: A total of 800 suspension specimens including 200 samples for each technique were simultaneously and parallel processed for comparing the diagnostic efficiency of the formalin-tween (FTC), formalin-ether (FEC), formalin-acetone (FAC), and formalin-gasoline concentration (FGC) techniques.Results: Sensitivity of FTC, FEC, FAC, and FGC techniques for diagnosis of intestinal parasites was 71.7%, 55.8%, 70.0% and 56.7%; and their negative predictive values (NPV) were 70.2%, 60.2%, 69.0% and 60.6%, respectively. FTC and FAC techniques with equivalent recovery rates were significantly more sensitive than FEC and FGC techniques for diagnosing helminth ova, but for diagnosis of protozoan cysts they were reversed. Overall diagnostic k agreement for FTC and FAC techniques was substantial, while for FEC and FGC techniques it was moderate. The k statistic indicated low to moderate agreement for diagnosis of helminths and moderate to substantial agreement for protozoa.Conclusion: Tween, acetone and gasoline reagents are more stable, safer, less flammable and of lower cost than that of ether; and promise to be a useful alternative to ether- concentration. Our results demonstrated that the combined use of parasitological techniques is important for the diagnosis of all intestinal parasites. FTC and FGC techniques are superior for the diagnosis of helminth ova and protozoan cysts in stool, respectively. Additional studies are suggested, using a larger sample size and different parasites in the field.Keywords: Concentration technique, Diagnosis, Intestinal parasite, Sensitivity, NPV, FAC, FTC, FEC, FG

A Study on Rodent Ectoparasites in the North district of Tehran, Iran

Rodent ectoparasites seems have a main role in transmission of some zoonotic pathogens from commensal rats to human and pets such as leishmaniasis, plague, CCHF, etc. So rodents as the main reservoirs, are potential health dangers in human communities. The aim of this study was to determine the prevalence and frequency of identified ectoparasites in north of Tehran.Rodents were captured with live traps during 2007-2009. After transferring to the laboratory and identifying, their ectoparasites were collected and mounted for species identification by using valid keys. Sixty four rodents included two species: Rattus norvegicus (82.8%) and Mus musculus (17.2%) were captured. 1755 ectoparasites collected from 43 infested R.norvegicus were related to 5 genera and 6 species: Ornithonyssus bacoti (71.7%), Hoplopleura spp (17%), Hoplopleura oenomydis (11.3%), Polyplax spinulosa (3.8%), Nosopsyllus fasciatus (3.8%), and Ixodes ricinus (1.9%). 11 Mus musculus were free of ectoparasites. Among all arthropods, mites and ticks had the most (97.4%) and the least (0.1%) frequency in R.norvegicus, respectively. Also, Ornithonyssus bacoti was a prevalent species (71.7%) with mean abundant 32.2. I.ricinus with 1.9% prevalence was the least prevalent ectoparasites. 11 M.musculus were free of ectoparasites