Diagnosis of abdominal angiostrongyliasis by PCR from sera of patients

Abdominal angiostrongyliasis is a zoonotic infection caused by an intra-vascular nematode parasitic of wild rodents, Angiostrongylus costaricensis. No parasitological diagnosis is currently available and immunodiagnosis presents several drawbacks. Primers constructed based on a congeneric species, A. cantonensis, were able to amplify a 232 bp fragment from serum samples of 3 patients with histopathological diagnosis. Extraction was better performed with DNAzol and the specificity of the primers was confirmed by Southern blot. This disease has been diagnosed with frequency in south of Brazil, thus, this method appears like the important and unpublished alternative to improve diagnostic of disease.

Comparison between immunomagnetic separation, coupled with immunofluorescence, and the techniques of Faust et al. and of Lutz for the diagnosis of Giardia lamblia cysts in human feces

In the present study, the performance of Immunomagnetic Separation technique, coupled with Immunofluorescence (IMS-IFA), was compared with the FAUST et al. and Lutz parasitological techniques for the detection of Giardia lamblia cysts in human feces. One hundred and twenty-seven samples were evaluated by the three techniques at the same time showing a rate of cyst detection of 27.5% by IMS-IFA and 15.7% by both Faust et al. and Lutz techniques. Data analysis showed a higher sensitivity of IMS-IFA for the detection of G. lamblia cysts in comparison with the techniques of FAUST et al. and Lutz. The use of this methodology as a routine procedure enables the processing of many samples simultaneously, in order to increase recovery rate of G. lamblia cysts and reduce the time of sample storage.

Molecular analysis of the dengue virus type 1 and 2 in Brazil based on sequences of the genomic envelope-nonstructural protein 1 junction region

The genomic sequences of the Envelope-Non-Structural protein 1 junction region (E/NS1) of 84 DEN-1 and 22 DEN-2 isolates from Brazil were determined. Most of these strains were isolated in the period from 1995 to 2001 in endemic and regions of recent dengue transmission in São Paulo State. Sequence data for DEN-1 and DEN-2 utilized in phylogenetic and split decomposition analyses also include sequences deposited in GenBank from different regions of Brazil and of the world. Phylogenetic analyses were done using both maximum likelihood and Bayesian approaches. Results for both DEN-1 and DEN-2 data are ambiguous, and support for most tree bipartitions are generally poor, suggesting that E/NS1 region does not contain enough information for recovering phylogenetic relationships among DEN-1 and DEN-2 sequences used in this study. The network graph generated in the split decomposition analysis of DEN-1 does not show evidence of grouping sequences according to country, region and clades. While the network for DEN-2 also shows ambiguities among DEN-2 sequences, it suggests that Brazilian sequences may belong to distinct subtypes of genotype III.

PCR - based diagnosis to evaluate the performance of malaria reference centers

Although the Giemsa-stained thick blood smear (GTS) remains the gold standard for the diagnosis of malaria, molecular methods are more sensitive and specific to detect parasites and can be used at reference centers to evaluate the performance of microscopy. The description of the Plasmodium falciparum, P. vivax, P. malariae and P. ovale ssrRNA gene sequences allowed the development of a polymerase chain reaction (PCR) that had been used to differentiate the four species. The objective of this study was to determine Plasmodium species through PCR in 190 positive smears from patients in order to verify the quality of diagnosis at SUCEN's Malaria Laboratory. Considering only the 131 positive results in both techniques, GTS detected 4.6% of mixed and 3.1% of P. malariae infections whereas PCR identified 19.1% and 13.8%, respectively.

Neurocryptococcosis: diagnosis by PCR method

Cryptococcus neoformans detection was optimized using PCR technique with the objective of application in the clinical laboratory diagnosis. The amplification area was ITS and 5,6S which encodes the ribosomal RNA (rRNA). A total of 72 cerebrospinal fluid (CSF) samples were used, obtained from cases with and without AIDS. The patients had cryptococcal meningitis (n = 56) and meningitis caused by other agents (n = 16). The results demonstrated that PCR test had the highest sensitivity rates, superior to culture (85.7%) and to India ink test (76.8%). PCR was found to be sensitive in detecting 1 cell/mL and highly specific since it did not amplify other fungal DNA. The comparative analysis of the methods showed that PCR is more sensitive and specific and is applicable as an important laboratorial resource for neurocryptococcosis diagnosis.

Dot-ELISA for the diagnosis of neurocysticercosis

The aim of the present study was to standardize and evaluate dot-Enzyme linked immunosorbent assay (Dot-ELISA), a simple and rapid test for the detection of cysticercus antibodies in the serum for the diagnosis of neurocysticercosis (NCC). The antigen used in the study was a complete homogenate of Cysticercus cellulosae cysts obtained from infected pigs and dotted on to nitrocellulose membrane. Test sera were collected from the patients of NCC, and control sera from patients with other diseases and healthy students and blood donors of the Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER) Hospital, Pondicherry, during a study period from 2001 to 2003. Dot-ELISA detected antibodies in 14 of 25 (56%) in clinically suspected cases of NCC, 13 of 23 (56.5%) in CT/MRI proven cases of NCC and 2 of 25 (8%) each in non-cysticercal CNS infection controls and healthy controls. The test showed a sensitivity of 56.25%, specificity of 92%, positive predictive value of 87.09%, and negative predictive value of 70.76%. Results of the present study shows that the Dot-ELISA as a simple test can be used in the field or poorly equipped laboratories for diagnosis of NCC .

Single step polymerase chain reaction (PCR) for the diagnosis of the Leishmania (Viannia) subgenus

In Brazil, the main etiologic agent of Leishmaniasis that frequently presents with mucosal involvement belongs to the Viannia subgenus. The therapeutic conduct in this disease depends on the parasitological diagnosis, and classical methods are restricted in identifying the agent. In this paper we describe a polymerase chain reaction (PCR), which uses primers designed from mini-exons repetitive sequences. The PCR amplifies a 177bp fragment that can distinguish (Viannia) from (Leishmania) subgenus. This test could be a useful diagnostic tool.

Disseminated nocardiosis due to Nocardia farcinica: diagnosis by thyroid abscess culture

A previously healthy 75-year-old white male dentist presented with a 6-month history of low-back pain treated with chronic steroid therapy had a Nocardia farcinica infection diagnosed by aspirate of thyroid abscess and six blood cultures. Despite the treatment with parenteral combination of trimethoprim/sulfamethoxazole, the patient failed to respond and died after two days of therapy. Autopsy revealed disseminated nocardiosis, involving lungs with pleural purulent exudate in both sides, heart, thyroid, kidneys, brain, bones, and lumbosacral soft tissue with destruction of L2-L4.