An Improved PCR-RFLP Assay for Detection and Genotyping of Asymptomatic Giardia lamblia Infection in a Resource-Poor Setting

Laboratory workers, in resource-poor countries, still consider PCR detection of Giardia lamblia more costly and more time-consuming than the classical parasitological techniques. Based on 2 published primers, an in-house one-round touchdown PCR-RFLP assay was developed. The assay was validated with an internal amplification control included in reactions. Performance of the assay was assessed with DNA samples of various purities, 91 control fecal samples with various parasite load, and 472 samples of unknown results. Two cysts per reaction were enough for PCR detection by the assay with exhibited specificity (Sp) and sensitivity (Se) of 100% and 93%, respectively. Taking a published small subunit rRNA reference PCR test results (6%; 29/472) as a nominated gold standard, G. lamblia was identified in 5.9% (28/472), 5.2%, (25/472), and 3.6% (17/472) by PCR assay, RIDA® Quick Giardia antigen detection test (R-Biopharm, Darmstadt, Germany), and iodine-stained smear microscopy, respectively. The percent agreements (kappa values) of 99.7% (0.745), 98.9% (0.900), and 97.7% (0.981) were exhibited between the assay results and that of the reference PCR, immunoassay, and microscopy, respectively. Restriction digestion of the 28 Giardia-positive samples revealed genotype A pattern in 12 and genotype B profile in 16 samples. The PCR assay with the described format and exhibited performance has a great potential to be adopted in basic clinical laboratories as a detection tool for G. lamblia especially in asymptomatic infections. This potential is increased more in particular situations where identification of the parasite genotype represents a major requirement as in epidemiological studies and infection outbreaks.

Use of "Parasep filter fecal concentrator tubes" for the detection of intestinal parasites in stool samples under routine conditions.

Parasitic gastrointestinal infections are a major cause of morbidity and mortality in the developing world, with stool microscopy being the mainstay of diagnostic practice. Both direct microscopy and concentration techniques can be utilized; direct microscopy may be time consuming and tedious; however clinical laboratories in developing countries lack trained staff who can effectively use concentration methods. In our practice we used the Parasep O and P filter concentrator tubes (manufactured by DiaSys Ltd, Berkshire, England. Product Code 146000) along with direct microscopic techniques and found that Parasep filters enhanced the ability to detect intestinal parasites that would have been missed on routine microscopy. We found the Parasep filter concentration method to be easy, cost-effective and reliable for routine stool examinations.

Pérdidas económicas por decomiso de hígados y distribución geográfica de la fasciolasis bovina en el estado de Tabasco, México / Economical wastes associated to sanitary confiscation of livers infested with bovine fasciolasis and geographic distribution of the illness in the state of Tabasco, Mexico

Entre enero de 1988 y abril de 1989, se revisaron 211,700 hígados de bovinos en el Frigorífico y Empacadora de Tabasco, S.A. de C.V. (Rastro TIF 51), de ganado procedente de los 17 municipios que conforman el estado de Tabasco. De los hígados revisados, 44,447 fueron decomisados por Fasciola hepatica, correspondiendo a un peso total de 250.206 Kg; que representó una pérdida de $ 1'626'339,000.00. Considerando sólo 1988, 31.995 hígados fueron decomisados representando un total de 1991,970 kg y una pérdida de $ 1'247'805,000.00. Fasciola hepatica se encuentra distribuida en todos los municipios del estado. Las prevalencias altas se registraron para las regiones de la Sierra y la Chontalpa, las moderadas en la región Centro y las bajas en la región de los Ríos. Los valores más altos en cuanto a la prevalencia se presentaron en los meses de mayo, junio, julio y octubre de 1988 y en marzo de 1989