Spatial risk analysis on occurrences and dispersal of Biomphalaria straminea in and endemic area for schistosomiasis.

BACKGROUND & OBJECTIVES: : Schistosomiasis is a rural endemic disease that has been expanding to urban and coastal areas in the state of Pernambuco, Brazil. The aim of this study was to characterize the distribution of breeding sites of the causative vector, Biomphalaria straminea in an endemic municipality for schistosomiasis and to present the predictive models for occurrences and dispersal of this vector snail to new areas. METHODS: : A malacological survey was conducted during January to December 2015 in the municipality of São Lourenço da Mata, Pernambuco, Brazil to identify the breeding sites of Biomphalaria. Faecal contamination was determined by means of the Colitag™ diagnostic kit. Rainfall data were collected, and correlated with snail distribution data. Kernel density estimation, kriging and maximum entropy (MaxEnt) modeling were used for spatial data analysis, by means of the spatial analysis software packages. RESULTS: : Out of the 130 demarcated collection points, 64 were classified as breeding sites for B. straminea. A total of 5,250 snails were collected from these sites. Among these 64 sites, four were considered as foci of schistosomiasis transmission and 54 as potential transmission foci. An inverse relationship between rainfall and snail density was observed. Kernel spatial analysis identified three areas at higher risk of snail occurrence, which were also the areas of highest faecal contamination and included two transmission foci. Kriging and MaxEnt modeling simulated the scenarios obtained through the kernel analyses. INTERPRETATION & CONCLUSION: : Use of geostatistical tools (Kriging and MaxEnt) is efficient for identifying areas at risk and for estimating the dispersal of Biomphalaria species across the study area. Occurrence of B. straminea in the study area is influenced by the rainy season, as it becomes more abundant during the period immediately after the rainy season, increasing the risk of dispersal and the appearance of new transmission foci.

Nested polymerase chain reaction in cerebrospinal fluid for diagnosing spinal cord schistosomiasis: A promising method.

INTRODUCTION: Spinal cord schistosomiasis is a neglected, disabling neurological disease commonly identified in patients from northeast Brazil. The methods currently available for its diagnosis need improvement. PCR in feces and urine is a sensitive diagnostic tool for diagnosis of schistosomiasis, but its value in the cerebrospinal fluid (CSF) is still unknown. OBJECTIVE: The objective of this study was to detect Schistosoma mansoni DNA in CSF from patients with spinal cord schistosomiasis, using the nested PCR (NPCR) assay. METHODS: This was a cross-sectional study carried out from March 2013 to January 2014 at the Aggeu Magalhães Research Center/FIOCRUZ (Pernambuco state, Brazil). NPCR was used to detect Schistosoma mansoni DNA in CSF samples from 20 patients with spinal cord schistosomiasis and 30 controls. RESULTS: NPCR was positive in 16 patients with spinal cord schistosomiasis and none from the control group (sensitivity 80%; specificity 100%, positive predictive value 100%; negative predictive value 88.2%). CONCLUSION: The NPCR technique is highly sensitive and specific for diagnosis of spinal cord schistosomiasis and can be an important diagnostic tool, particularly in cases with negative CSF serology.

Cerebral toxoplasmosis in patients with acquired immune deficiency syndrome in the neurological emergency department of a tertiary hospital.

INTRODUCTION: Cerebral toxoplasmosis is the most common cause of space occupying brain lesion in patients with HIV/AIDS in Brazil. In the post-HAART era, it is responsible for high rates of morbidity and mortality worldwide. MATERIALS AND METHODS: This study consists of a case series of 56 patients diagnosed with cerebral toxoplasmosis whose clinical features, brain imaging and cerebrospinal fluid aspects were analyzed. RESULTS: Cerebral toxoplasmosis led to the diagnosis of infection by the human immunodeficiency virus (HIV) in 27 (48.2%) of the patients, while 29 (51.2%) others already knew to be HIV seropositive. However, at the time of diagnosis of cerebral toxoplasmosis, only 9 (16.6%) reported being under antiretroviral therapy and 5 (8.9%) were receiving primary prophylaxis for toxoplasmosis. Headache, strength deficit and fever were the most frequent signs and symptoms throughout the study. Fifty-three patients showed changes consistent with toxoplasmosis in CT or MRI. Thirty-four (60.7%) CSF samples were positive in the indirect haemagglutination test and for the reaction of Toxoplasma gondii IgG ELISA, while 31 (55.4%) were positive in the direct haemagglutination test. Fifty (89.3%) patients underwent first-line treatment for toxoplasmosis. CONCLUSION: Cerebral toxoplasmosis is still a very relevant neurological disease in individuals with AIDS admitted to neurology emergency departments. Early diagnosis and initiation of empiric treatment and antiretroviral therapy are important for good prognosis.

Avaliação da especificidade dos primers RV1 e RV2 para o diagnóstico molecular da leishimaniose visceral / Evaluation of the specificity of the primers RV1 and RV2 for the molecular diagnosis of visceral leishimaniose

A Leishmaniose Visceral (LV) é uma endemia de grande expansão geográfica e, na maioria das áreas endêmicas, co-existe com outras doenças. No Brasil há descrição, em vários municípios, de co-endemias tais como esquistossomose, tuberculose, doença de chagas e leishmaniose tegumentar americana, e estas apresentam manifestações clínicas semelhantes à LV, o que pode interferir na especificidade dos métodos diagnósticos convencionais. O minicírculo do kDNA é o alvo mais estudado e aplicado nas pesquisas da leishmaniose humana. Dentre os primers que tem o kDNA como alvo estão o RV1 e RV2, que já foram aplicados com sucesso em diversas amostras biológicas. Este trabalho teve como objetivo estudar a especificidade dos primers RV1 e RV2, através da técnica de PCR, utilizando DNA de diferentes organismos. Para isto, utilizou-se a ferramenta Primer-BLAST (NCBI), para observar, teoricamente, quais os organismos que possuem regiões para o anelamento dos primers; e, em laboratório, foram testados DNA genômico purificado de diversos organismos. A sensibilidade dos primers foi testada através de uma curva de diluição seriada utilizando o DNA genômico de Leishmania (Leishmania) chagasi para dois sistemas de volumes diferentes. O Sistema de PCR 2, com 50 ?L, apresentou uma sensibilidade de 0,1fg, enquanto que o Sistema de PCR 1, com 25 ?L, alcançou apenas 1 pg. Testando os primers dos sistemas de forma teórica (Primer-BLAST), estes mostraram-se específicos para Leishmania (Leishmania) major, Leishmania (Leishmania) donovani e Leishmania. (Leishmania) infantum. Porém ao testar, em laboratório, o DNA dos organismos com o sistema de PCR 2, observou-se inespecificidade dos primers, que se anelaram frente ao DNA de Schistosoma mansoni e Trypanosoma cruzi, para as mesmas condições de ciclagem. Os resultados encontrados demonstram que os primers RV1 e RV2 não devem ser utilizados em regiões onde estes parasitos estão presentes, pois podem levar a resultados falso-positivos.

The Visceral Leishmaniasis (VL) is endemic to a large geographic spread and, in most endemic areas, co-exist with other diseases. In Brazil there are descriptions, in various municipalities, of co-endemic diseases such as schistosomiasis, tuberculosis, chagas disease and american tegumentary leishmaniasis, and those with clinical symptoms similar to VL, which can interfere with the specificity of conventional diagnostic methods.The minicircle kDNA is the target most studied and applied in research of human leishmaniasis. Among the primers that target the kDNA, are RV1 and RV2, which has already been successfully applied in various biological samples. This work aimed to study the specificity of the primers RV1 and RV2, by PCR, using DNA from different organisms. For this, we used the Primer-BLAST tool (NCBI), to observe, theoretically, which organisms have regions for annealing ofprimers, and in the laboratory were tested purified genomic DNA of various organisms. The sensitivity of primers was tested by a serial dilution curve using genomic DNA from Leishmania (Leishmania) chagasi for two systems with different volumes. The PCR System2, with 50 ìL, showed a sensitivity of 0.1 fg, whereas the PCR System 1, with 25 ìL, reached only 1 pg. Testing primers in a theoretical way (Primer-BLAST), they showed specificity forLeishmania (Leishmania) major, Leishmania (Leishmania) donovani and Leishmania (Leishmania) infantum. But when testing, in laboratory, the DNA of the organisms using the PCR system 2, was observed inspecificity of the primers, which showed amplification against the DNA of Schistosoma mansoni and Trypanosoma cruzi, using the same cycling conditions. The results show that the primers RV1 and RV2 must not be used in regions where theseparasites are present, because they may lead to false positive results.