[Contribution of the PCR assay to the diagnosis of Mansonella ozzardi in endemic areas of Argentina]. / Aporte de la técnica de PCR en el diagnóstico de Mansonella ozzardi en zonas endémicas de la Argentina.

Mansonella ozzardi is a tissue-dwelling parasitic nematode, the causative agent of mansonelliasis in almost all Latin American countries. It has been described along the Argentine Yungas region. The microscopic diagnosis can yield false-negative test results at low microfilaremia levels. The aim of this study was to optimize the molecular diagnostic technique and compare it with the Knott's method and standard blood smear procedures (thin blood films and thick smears) in 92 blood samples of individuals from an endemic area. The PCR technique followed by the sequencing of the amplified product yielded 100 % sensitivity compared to the Knott's test, which is considered a reference method. Seven more cases of this parasitosis could only be identified with the molecular technique.

Aporte de la técnica de PCR en el diagnóstico de Mansonella ozzardi en zonas endémicas de la Argentina / Contribution of the PCR assay to the diagnosis of Mansonella ozzardi in endemic areas of Argentina

Mansonella ozzardi es un nematode parásito tisular, agente etiológico de mansonellosis en casi la totalidad de los países latinoamericanos. En Argentina la mansonellosis ha sido descrita a lo largo de la región de las yungas. Su diagnóstico microscópico puede dar resultados falsos negativos en microfilaremias bajas. El objetivo del presente estudio fue optimizar su diagnóstico molecular y comparar los resultados con los obtenidos mediante las pruebas microscópicas de Knott, de gota gruesa y de extendido hemático fino, en 92 muestras de sangre de pacientes de zona endémica. La técnica de PCR seguida de la secuenciación del producto amplificado presentó una sensibilidad del 100 % frente al método de Knott, considerado como referencia, e incluso permitió identificar 7 casos más de la parasitosis.

Mansonella ozzardi is a tissue-dwelling parasitic nematode, the causative agent of mansonelliasis in almost all Latin American countries. It has been described along the Argentine Yungas region. The microscopic diagnosis can yield false-negative test results at low microfilaremia levels. The aim of this study was to optimize the molecular diagnostic technique and compare it with the Knott's method and standard blood smear procedures (thin blood films and thick smears) in 92 blood samples of individuals from an endemic area. The PCR technique followed by the sequencing of the amplified product yielded 100 % sensitivity compared to the Knott's test, which is considered a reference method. Seven more cases of this parasitosis could only be identified with the molecular technique.

Systemic sarcocystosis in a patient with acquired immune deficiency syndrome.

Sarcocystis sp is a tissue coccidian parasite in humans that causes intestinal and muscular sarcocystosis in immunocompetent patients. Intestinal sarcocystosis can be diagnosed at the tissue level in the lamina propria of the small bowel and by fecal examination. Muscular sarcocystosis is diagnosed by microscopic examination of muscle biopsies. This report describes a case of systemic sarcocystosis in an HIV-infected patient. We studied a 31-year-old patient with AIDS, chronic diarrhea, cholestatic hepatitis, and musculoskeletal pain by stool analysis and endoscopy with duodenal and liver biopsy specimens that were processed for routine histology. The microgamete and macrogamete stages of Sarcocystis sp were present in the lamina propria, with sporulated oocysts in feces. Schizont stages of the protozoa were found in liver biopsy. In summary, sarcocystosis should be considered another opportunistic infection in HIV-infected patients.

Identification and characterization of an interspersed repetitive DNA fragment in Plasmodium vivax with potential use for specific parasite detection.

We cloned and characterized a Plasmodium vivax repeat element of 7872bp named PvRE7.8. Several internal tandem repeats were found along the sequence. The repetitive nature of the PvRE7.8 element was confirmed by hybridization of a P. vivax YAC library. Based on the data bank analysis and the presence of two contiguous putative genes that may encode proteins related to DNA metabolism, PvRE7.8 could be considered an inactivated transposon-LINE element. By using Pv79 as probe or primers derived from Pv79-flanking sequences, P. vivax DNA Could be detected from whole blood and mosquito samples. We consider that the repeat element described here has potential for P. vivax malaria diagnosis and for epidemiological analysis of P. vivax transmission areas.