Isolation of Naegleria fowleri from a domestic water tank associated with a fatal encephalitis in a 4 month-old Venezuelan child

This study describes the association of household water system contamination with the pathogenic Free-Living Amoeba (FLA) Naegleria fowleri and a case of fatal Primary Amoebic Meningoencephalitis (PAM) in a child from the state of Monagas in Venezuela. Amoebae were initially identified by microscopy from a sample of cerebrospinal fluid (CSF) from the child. Direct DNA extraction and specific PCR/sequencing for N. fowleri was also carried out from the same CSF sample. In order to determine a possible environmental source of infection, water samples from the water tank of the child's home and also water bodies recently visited by the child and his family, were examined for the presence of N. fowleri by culture and PCR/sequencing. The results obtained from the collected water samples revealed that only the water tank of the house was positive for N. fowleri. PCR/sequencing showed that the strains isolated from the patient and the water tanks were 100 % identical. Therefore, the house water tank was confirmed as the source of infection in this case, possibly as a result of the occasional immersion of the child´s head under the water while bathing. This case highlights a novel source of thermally polluted water and another threat of N. fowleri infection.

Oral transmission of Chagas disease: typing of Trypanosoma cruzi from five outbreaks occurred in Venezuela shows multiclonal and common infections in patients, vectors and reservoirs

In Venezuela six episodes of oral transmission of Chagas disease (OChD) have been described, being the one reported in 2007 with a total of 103 people infected the largest worldwide. This work shows the use of three molecular markers (mini-exon gene and domains 24Sα and 18S of the ribosomal RNA) to characterize the infecting Trypanosoma cruzi strain of patients, reservoirs and vectors involved in five of the six OChD outbreaks. For this, 28 T. cruzi isolates were characterized by PCR, and the products of these reactions cloned and sequenced to reveal the existence of different TcI SL-IR genotypes. We also describe a new PCR assay able to discriminate between TcIb and TcId parasite populations. In summary, we have identified mostly parasites with the TcId haplotype and multiclonal populations with predominance of haplotype TcId (65.2%). Additionally, populations of haplotypes TcIb, TcIa and mixtures (TcId+TcIb, TcId+TcIa, TcIb+TcIa) are recurrent in samples obtained from children. The analysis of the SL-IR motif showed two clones depicting a different motif that could be an evidence for a possible hybrid haplotype between TcIa and TcIb (haplotype TcIa/Ib). Interestingly, in a single patient haplotype differences between T.cruzi isolates obtained pre and post-treatment were found. In conclusion, our findings show that in order to understand the pathogenic mechanisms involved in the orally acquired Chagas disease there is a need to join efforts to study T. cruzi haplotypes, their tissue tropisms and their susceptibility to chemoteraphy.

Identification of genotypes of Giardia intestinalis of human isolates in Egypt

In Egypt, the genotyping study of Giardia intestinalis in human is limited. To determine the prevalence of G. intestinalis, faecal samples were collected from Egypt. Samples were concentrated using density gradient centrifugation. The samples were subjected to PCR and DNA sequence analysis for TPI gene. Prevalence of Giardia infection was 34.6% of 52 examined. DNA sequence showed that the Assemblage B was the most prevalent (80%) genotype, the 15% of the positive samples belonged to Assemblage E, and the 5% of them belonged to Assemblage A. Certainly, both genotypes A and B are highly common in human worldwide. However, up to now, Assemblage E had not been known to be infectious for humans. Therefore, this is the first time that Assemblage E is reported in human. However, further analyses of a second locus are required to confirm this result. The extent to which Giardia-infected cattle in Egypt might pose a risk of human infection is unknown.

Taenia spp.: 18S rDNA microsatellites for molecular systematic diagnosis

The 18S rDNA gene of adult worms of Taenia parva found in Genetta genetta in the Iberian Peninsula and larval stages of T. pisiformis from the wild rabbit (Oryctolagus cuniculus) in Tenerife (Canary Islands) were amplified and sequenced. The sequences of the 18S rDNA gene of T. parva (1768 bp) and T. pisiformis (1760 bp) are reported for the first time (GenBank accession nos. AJ555167–AJ555168 and AJ555169–AJ555170, respectively). In 168 alignment positions microsatellites in the 18S rDNA of both taxa were detected for the first time (TGC in T. parva and TGCT in T. pisiformis) and differences in their sequences with different repetition numbers were observed. The use of nucleotide sequences of this gene in the resolution of systematic problems in cestodes is discussed with reference to the systematic status of Taenia spp. and mainly in human taeniids such as T. solium, T. saginata, and Asian human isolates of Taenia.

The sera from individuals suffering from cutaneous leishmaniasis due to Leishmania brazilensis present antibodies against parasitic conserved proteins, but not their human counterparts

Sera from individuals suffering from leishmaniasis have been shown to strongly react against conserved proteins from the parasite, such as ribosomal, histones and heat-shock proteins. Some of these proteins have also been described as immunogenic in several auto-immune syndromes, and the detection of antibodies against them is considered to be indicative of disorder of the immune system. In this paper, we investigate whether there is any relationship between the recognition of some conserved proteins from leishmania braziliensis by individuals suffering from cutaneous (CL) and mucocutaneous (MCL) leishmaniasis, and the recognition of the human homologues of these antigens found in sufferers from autoimmune diseases. Our findings reveal that the immune response generated during CL and MCL is elicited specifically by the parasitic histone H1 and Hsp70, since the CL and MCL sera do not react against their human counterparts. In addition, evidence is presented showing the specific recognition of human proteins by the autoimmune sera, showing only a weak cross-reaction with the most divergent regions of the parasitic proteins.

Pathogenic Acanthamoeba strains from water sources in Jamaica, West Indies

In 2004, samples of tap water and of river and sea water associated with human activities were collected in Jamaica, West Indies, and checked for free-living Acanthamoeba. The morphologies of the cysts and trophozoites observed and the results of PCR-based amplifications with a genus-specific primer pair were used to identify the Acanthamoeba isolates. The potential of each isolate as a human pathogen was then evaluated using thermotolerance and osmotolerance assays and two PCR-based assays for Acanthamoeba pathogenesis. Acanthamoeba were identified in 36.1%, 26.4% and 49.6% of the tap-, river- and sea-water samples collected, respectively. Pathogenic potential was shown by 60.0% of the Acanthamoeba strains isolated from tap water, 68.4% of the strains from river water, and 40.4% of the seawater strains. Sequencing of ribosomal DNA revealed the T1, T2, T4, T5, T7, T9 and T11 genotypes. Isolates of the T4 genotype were collected from tap, rain and sea water and, as expected, exhibited the most pathogenic traits; most were osmotolerant, thermotolerant and expressing extracellular serine protease. This is the first study of the occurrence and distribution of Acanthamoeba in water in the West Indies, and the results confirm the presence of potentially pathogenic strains in Jamaica.

Raillietiella morenoi sp. n. (Pentastomida) from Gallotia atlantica (Peters and Doria, 1882) (Lacertidae) in the Canary Islands

Raillietiella morenoi sp. n., a new cephalobaenid pentastomid found in the lungs of Gallotia atlantica collected in the Canary Islands, is described. The new species belongs to the sharp-tipped posterior-hook type. The annulus number, morphology, and dimensions of copulatory spicules and the dimensions of anterior and posterior hooks separate Raillietiella sp. n. from the other raillietiedid sharp-tipped posterior-hook species of small lizard parasites in Africa. The host character of endemic protected species of G. atlantica in Alegranza Island posed great difficulty in obtaining more parasite materials. However, more studies are required to state the variability of this species and its possible distribution in other species in the Canary Islands, as well as in other Gallotia spp.

A specific primer pair for the diagnosis and identification of Acanthamoeba astronyxis by random amplified polymorphic DNA-polymerase chain reaction

Random amplified polymorphic DNA (RAPD) is a useful tool for species identification. The obtained band patterns can be used for specific primer pair design that is useful for species identification. In this study, a distinctive 485-bp band in Acanthamoeba astronyxis band patterns was found, using the OPC20 primer (ACTTCGCCAC). The band specificity was confirmed by hybridization, using it as a probe, against all OPC20 amplifications from different Acanthamoeba species. Once the fragment was sequenced, we used it to design a specific primer pair that was useful for the identification of different isolates as A. astronyxis species.

Parasites of Columba livia (Aves: Columbiformes) in Tenerife (Canary Islands) and their role in the conservation biology of the laurel pigeons

The prevalence and intensity of the parasites from 50 wild doves (Columba livia) from the city of Santa Cruz de Tenerife, in the island of Tenerife (Canary Archipelago), were studied. The following ectoparasites were found in apparently healthy pigeons (prevalences are shown in percentage (%) and mean intensities with their standard deviations): the acari Dermanyssus gallinae (De Geer, 1778) (6, 241.0 +/- 138.9) and Tinaminyssus melloi Fain, 1962 (10%, 218.3 +/- 117.3); the louses, Columbicola columbae Linnaeus, 1758 (100%, 111.4 +/- 76.8) and Campanulotes bidentatus Scopoli, 1763 (94%, 48.4 +/- 26.6); and the pigeon fly, Pseudolynchia canariensis Macquart, 1839 (36%, 6.2 +/- 1.6). The endoparasites we found were: a haemoprotozoan species, Haemoproteus columbae Kruze, 1890 (82%, 14.8 +/- 10.3 per 1000); coccidian oocysts, Eimeria sp. (50%, 0.2 x 10(3) +/- 1.7 x 10(3) per gr); a cestode species Raillietina micracantha (Fuhrmann, 1909) López Neyra, 1947 (44%, 12.3 +/- 9.4); and four nematode species, Tetrameres (Tetrameres) fissispina (Diesing, 1861) Travassos, 1915 (4%, 99.5 +/- 34.1), Synhimantus (Dispharynx) spiralis (Molin, 1858) (8%, 46.8 +/- 11.6), Ascaridia columbae (Gmelin, 1790) Travassos, 1913 (40%, 8.4 +/- 8.8) and Aonchotheca sp. (18%, 6.0 +/- 3.1). Several species detected in our study can be pathogens for C. bollii and C. junoniae, which are endemic pigeons of the Canary Islands, considered endangered species. Parasites (ectoparasites, protozoa and helminths) of C. livia found in Tenerife and others from wild and farm birds in the island were considered as healthy controls.

Molecular Characterization of the Leishmania braziliensis L6 Ribosomal Protein

By screening a Leishmania braziliensis complementary DNA library with a pool of sera from leishmaniasis patients, the gene coding for L6 ribosomal protein was isolated. The sequence, genomic organization, and transcription of this gene are described in this article. The sequence analysis of the L. braziliensis L6 gene shows a single open reading frame, which codes for a protein of 192 amino acids (aa) with a hypothetical molecular mass of 20.9 kDa. The protein exhibits significant sequence similarity to L6 ribosomal proteins from higher eukaryotes and yeast. Thus, the L. braziliensis L6 protein contains 4 functional motifs, which are located at equivalent positions in other L6 ribosomal proteins described previously. Interestingly, the L6 ribosomal protein from L. braziliensis contains a specific region of 14 aa and a tyrosine kinase motif, which is absent in human and C. elegans L6 protein. The locus coding the L. braziliensis L6 ribosomal protein is formed by 2 gene copies arranged in tandem and located in a chromosome of approximately 0.9. Mb. The genes are actively transcribed as 2 polyadenylated transcripts of approximately 1.15 and 0.85 kb, which differ in their steady-state level and stability.

Molecular systematics of several cyclophyllid families (Cestoda) based on the analysis of 18S ribosomal DNA gene sequences

The sequences of the 18S small subunit ribosomal DNA of five species of cyclophyllidean cestodes from the families Davaineidae, Anoplocephalidae and Dilepididae were determined. A species of tetrabothridid was also sequenced. These 18S sequences were combined with other available eucestode sequences in GenBank. From the 1,838 sites in the alignment, 375 bp (20%) were excluded from the analysis due to alignment issues inferred by manual inspection. Phylogenetic trees were obtained by maximum parsimony, neighbour-joining distance and maximum likelihood methods. Analyses showed that Cyclophyllidea is monophyletic and separate from Tetrabothrius spp. Lyruterina nigropunctata, which is now included in the family Paruterinidae, is more closely related to davaineids of the genus Raillietina than Pseudidiogenes nana (Davaineidae). P. nana and Choanotaenia infundibulum (Dilepididae) derive from the Davaineidae (or Raillietininae). The two species of Taenia (T. parva and T. pisiformis) formed a monophyletic sister group to the Davaineidae and Anoplocephalidae. The systematics of the Paruterinidae have been problematic and our results suggest a review of this family including other species with paruterine organ located in other families. The position of the Idiogeninae as a subfamily in the Davaineidae is also reviewed.

RAPD method useful for distinguishing Leishmania species: design of specific primers for L. braziliensis

The technique of Random Amplification Polymorphic DNA allows fragments of the genome to be amplified by means of polymerase chain reaction (PCR) without previous knowledge of their sequences. The protozoa of the genus Leishmania present great genetic variability, making it difficult to characterize the different species. A method is developed with a single 10-mers long primer, which allows the species L. braziliensis, L. mexicana, L. infantum, L. tropica, L. chagasi, L. amazonensis and L. major to be differentiated. These products amplified by RAPD have also facilitated the design of some primers that amplify L. braziliensis DNA exclusively.

Molecular and immunological characterization of L14 ribosomal protein from Leishmania braziliensis

The isolation and molecular characterization of the gene coding for L14 ribosomal protein from L. braziliensis is described. There are 2 copies of the gene per haploid genome, repeated in a head-to-tail tandem orientation and located in a single chromosome of approximately 950 kb. Northern blot analyses indicate the presence of a single transcript of 0.95 kb which is up-regulated when parasites reach the stationary growth phase. L. braziliensis L14 gene codes for a 175 amino acid long polypeptide showing 75-83% sequence identity with L14 proteins from trypanosomatids and approximately 25% with its counterparts from higher eukaryotic organisms. L14 ribosomal proteins from trypanosomatids and higher eukaryotes share along their molecules a similar distribution pattern of theoretically functional domains. L. braziliensis L14 recombinant protein is not recognized by sera from cutaneous leishmaniasis patients. Immunization of mice with one dose of L14 recombinant protein and a second dose of L14 protein covalently linked to the HSP70 from Trypanosoma cruzi induces a high antibody level against this L14 protein, which is mostly of the IgG2a subtype, as well as a strong increase in splenocyte proliferation index.

Helminths of the wild rabbit (Oryctolagus cuniculus) in Macaronesia

Two hundred and four rabbits from 8 Macaronesian islands (Pico, San Jorge, San Miguel, Terceira, and Flores from Azores Archipelago; Tenerife and Alegranza from Canary Islands; and Madeira from Madeira Archipelago) were examined for helminth parasites between 1995 and 2000. Three species of cestodes, Taenia pisiformis (larvae), Andrya cuniculi, and Mosgovoyia ctenoides, and 5 species of nematodes, Trichuris leporis, Graphidium strigosum, Trichostrongylus retortaeformis, Passalurus ambiguus, and Dermatoxys hispaniensis, were identified. Only 3 species (M. ctenoides, T. retortaeformis, and P. ambiguus) were regularly distributed over the 3 archipelagos. Taenia pisiformis was not collected in Madeira, nor was A. cuniculi in the Azores and G. strigosum in the Canary Islands. Trichuris leporis and D. hispaniensis were only found in Madeira. Significant differences in the general prevalence of the nematodes G. strigosum and T. retortaeformis were detected between Azores and Madeira. The prevalence of T. retortaeformis differs significantly between the Azores and the Canaries and that of P. ambiguus was higher in Madeira than in Azores and Canaries. The helminth richness found in the wild rabbit in these Macaronesian archipelagos was very low compared with the Palearctic helminth fauna of this host. The wild rabbit was introduced from the Iberian Peninsula into different Macaronesian islands. Helminths introduced with Oryctolagus cuniculus into these islands also are commonly found in Iberian wild rabbits, which are excellent colonizers, as demonstrated in this study.

Development of a rapid polymerase chain reaction-ELISA assay using polystyrene beads for the detection of Toxoplasma gondii DNA

AIMS

To develop a rapid colourimetric assay for the detection of Toxoplasma gondii DNA using polystyrene beads as solid support.

METHODS AND RESULTS

A nested-polymerase chain reaction (PCR)-ELISA assay for the detection of T. gondii DNA was standardized by optimizing the hybridization time and probe concentration. Its detection threshold was then determined and compared with Southern blotting hybridization. These were found to be equivalent, but the PCR-ELISA-beads test is easier to perform and the turnaround time is much shorter than with Southern blot.

CONCLUSIONS

The PCR-ELISA-beads assay is a valuable tool for the detection of T. gondii DNA.

SIGNIFICANCE AND THE IMPACT OF THE STUDY

Our results demonstrate that this PCR-ELISA assay, using polystyrene beads, can be used as a routine diagnostic test for the detection of T. gondii in clinical laboratories.

Analysis of NLS and rRNA binding motifs in the L25 ribosomal protein from Leishmania (viannia) braziliensis: investigation of its diagnostic capabilities

A cDNA clone codifying ribosomal protein L25 was isolated from a Leishmania braziliensis cDNA gene library. The alignment of the amino acid sequence deduced from this gene with other proteins revealed that this protein is related to the L23/25 rihosomal protein family. This is so because this protein shows, in its C-terminal end, the rRNA binding domains characteristic of these proteins and at the N-terminal end the NLS sequence necessary for its entry into the nucleus. Southern blot analysis showed 2 copies of gene L25 per genome arranged in tandem position and pointing in the same direction. Northern blot analysis showed that this gene is transcribed in 2 mRNAs when parasite promastigotes are in the logarithmic phase. In order to analyse the antigenic properties of L. braziliensis RPL25, it was purified as a recombinant protein and ELISA-tested against cutaneous, mucocutaneous and Chagasic sera. The results indicate that the recombinant RPL25 from L. braziliensis presents a non-specific reaction that disqualifies it for the diagnosis of cutaneous leishmaniasis. In contrast, some of the synthetic peptides derived from its sequence may serve as promising tools for the diagnosis of this disease.

Cloning and molecular characterization of the cDNA encoding histone H1 from Leishmania braziliensis

The isolation and molecular characterization of the histone H1-encoding gene from Leishmania braziliensis was carried out. The gene is present in the genome as a single copy and transcribed as a polyadenylated transcript of 830 nucleotides. The deduced amino acid sequence has in its central region the DNA binding K-[K/R]-A-A-[A/P] motif, which is repeated in tandem 9 times.

Small-scale isolation of high molecular weight DNA from Leishmania braziliensis

In this paper, we report a method for isolation of high molecular weight DNA from Leishmania promastigotes. This technique is especially indicated for small-scale purification of DNA suitable for the construction of highly representative genomic libraries. In our protocol, lysis buffer is compatible with RNase treatment, avoiding an additional precipitation step and consequent shearing of DNA. In order to prove the quality of the DNA isolated by this method, a Leishmania braziliensis genomic library was constructed, and an L. braziliensis KMP-11 gene was cloned after screening the library with a heterologous probe.

Validation of a rapid method for extraction of total RNA applied to Leishmania promastigotes

This report explains a rapid procedure (approximately 50 min) for the isolation of highly purified total RNA from Leishmania promastigotes based on extraction with acidic phenol. The simplicity of the manipulations required make this method ideal for processing multiple samples; the quality of the RNA obtained is suitable for reverse transcription polymerase chain reaction analysis.

PCR-ELISA for diagnosis of mucocutaneous leishmaniasis

In this work we demonstrate that the PCR-ELISA technique is sufficiently sensitive and specific for use as a diagnostic test in cases of mucocutaneous leishmaniasis. DNA was extracted from cultures of Leishmania braziliensis, Leishmania infantum, Leishmania tropica, Leishmania mexicana, Trypanosoma cruzi, and blood samples from individuals who presented a clinical diagnosis of leishmaniasis as well as from healthy individuals. The DNA was PCR amplified and the product obtained was hybridised with a biotin-labelled probe, the sequence of which was designed in our laboratory. The result of the hybridisation was visualised by means of an ELISA technique using antifluorescein antibody labelled with alkaline phosphatase and p-nitrophenylphosphate (pNFF) as chromogen. The optical density of the products of the pNFF hydrolysis was quantified in a spectrophotometer at a wavelength of 405 nm. Using this technique the percentage of detection was 83.3% in blood samples from patients clinically diagnosed as having mucocutaneous leishmaniasis. No false positive results were obtained.

A subtropical case of human babesiosis

This report constitutes the first well-documented case of symptomatic human babesiosis from a subtropical site, south of the 40th parallel. This paper describes the definitive identification of Babesia divergens infection in a splenectomized patient from the Canary Islands.

A serologic study of human toxocariasis in the Canary Islands (Spain): environmental influences

The presence of anti-Toxocara antibodies in the human population of the Canarian Archipelago was studied by means of an indirect enzyme-linked immunosorbent assay with excretory/secretory antigen of infective-stage larva. A total of 14,074 were analyzed, resulting in the following distribution and prevalence by location: southern Tenerife 6,435 (2.5% positive), northern Tenerife 1,710 (6.7% positive), La Palma 1,214 (4.5% positive), La Gomera 264 (6.8% positive), El Hierro 204 (3.9% positive), Gran Canaria 2,875 (2.3% positive). Fuerteventura 277 (1.8% positive), and Lanzarote 1,095 (2.9% positive). The weighted average of the entire Archipelago was 3.4% positive. Neither age nor sex was found to be significantly associated with positive serology. The influence of the different Canarian mesoclimates on the spreading of this zoonosis is demonstrated, with significant differences being found between humid and arid islands. Likewise, a significant positive correlation was found between De Martonne's humidity-aridity index and percentage of people with evidence of parasite exposure on the different islands.

Multiprimer PCR system for differential identification of mycobacteria in clinical samples

A novel multiprimer PCR method with the potential to identify mycobacteria in clinical samples is presented. The assay relies on the simultaneous amplification of three bacterial DNA genomic fragments by using different sets of oligonucleotide primers. The first set of primers amplifies a 506-bp fragment from the gene for the 32-kDa antigen of Mycobacterium tuberculosis, which is present in most of the species belonging to the genus Mycobacterium. The second set of primers amplifies a 984-bp fragment from the IS6110 insertion sequence of the bacteria belonging to the M. tuberculosis complex. The third set of primers, derived from an M. tuberculosis species-specific sequence named MTP40, amplifies a 396-bp genomic fragment. Thus, while the multiprimer system would render three amplification fragments from the M. tuberculosis genome and two fragments from the Mycobacterium bovis genome, a unique amplification fragment would be obtained from nontuberculous mycobacteria. The results obtained, using reference mycobacterial strains and typed clinical isolates, show that the multiprimer PCR method may be a rapid, sensitive, and specific tool for the differential identification of various mycobacterial strains in a single-step assay.

Massive breast hypertrophy in a young girl

A patient with massive virginal breast hypertrophy is reported in this study. A 16-year-old girl presented with abnormal growth of her breasts in 1 year. Due to the enormous breast volume, which caused her physical and psychological problems, she curtailed her social life. After a thorough gynecological and breast assessment, she was referred to the plastic surgery division for breast reduction. She underwent total subcutaneous mastectomy followed by immediate breast reconstruction by subpectoral prosthesis implantation.