Quantitative functional imaging of the pigeon brain: implications for the evolution of avian powered flight.

The evolution of flight is a rare event in vertebrate history, and one that demands functional integration across multiple anatomical/physiological systems. The neuroanatomical basis for such integration and the role that brain evolution assumes in behavioural transformations remain poorly understood. We make progress by (i) generating a positron emission tomography (PET)-based map of brain activity for pigeons during rest and flight, (ii) using these maps in a functional analysis of the brain during flight, and (iii) interpreting these data within a macroevolutionary context shaped by non-avian dinosaurs. Although neural activity is generally conserved from rest to flight, we found significant increases in the cerebellum as a whole and optic flow pathways. Conserved activity suggests processing of self-movement and image stabilization are critical when a bird takes to the air, while increased visual and cerebellar activity reflects the importance of integrating multimodal sensory information for flight-related movements. A derived cerebellar capability likely arose at the base of maniraptoran dinosaurs, where volumetric expansion and possible folding directly preceded paravian flight. These data represent an important step toward establishing how the brain of modern birds supports their unique behavioural repertoire and provide novel insights into the neurobiology of the bird-like dinosaurs that first achieved powered flight.

Parasitological and molecular characterization of Trypanosoma cruzi of triatomines and mammals from endemic areas for Chagas disease in Venezuela.

It is estimated that 6-7 million people worldwide are infected with Trypanosoma cruzi, the parasite that causes Chagas disease. In Venezuela, Chagas disease remains a public health problem. In this work, T. cruzi isolates from six species of triatomines and mammals of the orders Didelphimorphia and Xenarthra, captured in rural communities of Monagas, underwent parasitological and molecular characterization. A total of 471 triatomines and 17 mammals were captured, with a natural infection rate of 41.4% and 70.6%, respectively. In the male NMRI mouse model used for parasitological characterization (prepatent period, parasitemia curve, mouse mortality, and tissular parasitism), T. cruzi isolates exhibited high lethality due to their pronounced virulence, irrespective of the parasite load in each mouse, resulting in a mortality rate of 75%. Among the vector isolates, in the mouse model, only 2 out of 6 remained alive, while the rest perished during the evaluation. Conversely, the isolates from mammals proved fatal for all the inoculated mice. All isolates were identified as belonging to DTU TcI, based on the molecular markers such as the intergenic region of the miniexon, D7 divergent domain of the 24Sα rDNA, size-variable domain of the 18S rDNA, and hsp60-PCR-RFLP-EcoRV. This study demonstrates the presence of vectors and mammalian reservoirs naturally infected with T. cruzi in communities of Monagas, the 9th largest and 9th most populous state in Venezuela. This situation represents a neglected epidemiological problem demanding urgent attention and imperative health care intervention.

Detection of Trypanosoma cruzi DNA in false negative samples of collected triatomines, xenodiagnosis material, and biopsies of experimentally infected animals.

Direct test over the gut material from triatomine vectors and xenodiagnosis over mammalian hosts are classical techniques for Trypanosoma cruzi parasitological diagnosis. Nevertheless, negative results can be a source of uncertainty. Experimental models have allowed evaluating the tissue invasion of different strains of T. cruzi, but conventional techniques for tissue biopsies involve time-consuming and elaborated procedures and have low sensitivity. Gut material of collected triatomines (microscopically negative) (n = 114), material of mammal xenodiagnoses (microscopically negative) (n = 138), and biopsy material (microscopically negative) from experimentally infected animals (n = 34) with isolates from endemic areas of Chagas' disease from Venezuela were used for DNA extraction and PCR for the amplification of kinetoplast DNA (kDNA) and satellite DNA (sDNA) of T. cruzi. Positive PCR was observed in 53.6% of collected triatomine material, 15.8% of parasitological negative xenodiagnosis material, and 70.6% in biopsies, revealing underestimation by the parasitological tests and the valour of this analysis with preserved material. Anzoátegui was the state with the highest percentage of infection, and the triatomine species Rhodnius prolixus and Panstrongylus geniculatus had the highest percentages of infection. Didelphis marsupialis and Canis familiaris were the most infected by T. cruzi revealed by PCR of xenodiagnosis material. In addition, the PCR technique allowed demonstrating the invasion of T. cruzi in all tissues analyzed, constituting a molecular marker of tissue invasion.

Ecopathogenic complexes of American trypanosomiasis in endemic areas of Venezuela: Diagnosis and variability of Trypanosoma cruzi.

BACKGROUND & OBJECTIVES: Trypanosoma cruzi, the causative agent of American trypanosomiasis, has been reported in 180 mammalian species and 154 triatomines species of Neotropic. This is a clonal parasite with variable biological behaviour, associated with the genetics of the parasite and its hosts. To know the eco-pathogenic complex of this zoonosis, it was proposed to characterize T. cruzi isolates obtained from triatomines and domestic, peridomestic and wild mammals of the eastern and central-western regions of Venezuela. METHODS: The positivity to T. cruzi was established and the isolates were genetically characterized by PCR amplification of the mini-exon gene, the DNA coding for 24Sa and 18S rRNA, and polymorphic sequences-RFLPs. The sampling sites were georeferenced using the MapSource Software and ArcGis 9.3 programs to generate distribution maps of the isolates. RESULTS: Of the 460 hosts (205 triatomines and 255 mammals), 49% were positive for the parasite. On the other hand, 38 isolates obtained from the triatomines and 23 isolates obtained from mammals were evaluated. The TcI genotype predominated in most of the isolates; however, in those obtained from triatomines the presence of the TcIII genotype in single infections and TcI + TcIII or TcI + TcIV in mixed infections was also evidenced. INTERPRETATION & CONCLUSION: There is a possibility that the triatomines act as biological syringes for these genotypes associated exclusively to them. The heterogeneity in T. cruzi isolates demonstrated the complexity of parasitosis in these regions, presenting its control and prevention as a challenge.

Short communication: Four cases of Taenia saginata taeniasis in urban Venezuelan communities.

We report four cases of Taenia saginata taeniasis in different urban communities of Aragua state, Venezuela. After subsequent treatment with praziquantel and a saline purge, adult tapeworms were collected from all four patients and demonstrated to be T. saginata by morphological and molecular characterization. The finding of T. saginata in four distinct and separate urban municipalities of the Aragua state indicates the pertinence of rigorous meat inspection, and the importance of establishing parasite prevalence in human and bovine Venezuelan populations.

Molecular typing reveals the co-existence of two transmission cycles of American cutaneous leishmaniasis in the Andean Region of Venezuela with Lutzomyia migonei as the vector.

BACKGROUND The transmission routes for American cutaneous leishmaniasis (ACL) are in flux, so studies examining its transmission in humans, mammalian hosts, and sand fly vectors are urgently needed. OBJECTIVES The aim of this work was understand the epidemiological cycles of Leishmania spp., which causes ACL in the Andean Region of Venezuela, by identifying the Leishmania and the sand fly species involved in human and dog infections. METHODS Thirty-one biopsies from patients in Mérida and Táchira states with suspected ACL were studied by both parasitological tests (cultures and hamster inoculation) and a molecular test [Internal transcribed spacer 1 (ITS1) nested polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP)]. We also conducted a survey to detect Leishmania infection in dogs (Immunifluorescence antibody test and ITS1 nested PCR-RFLP) and sand flies (ITS1 nested PCR-RFLP) from El Carrizal, a highly endemic focus of ACL in Venezuela. FINDINGS Three different Leishmania species were identified in the clinical samples from humans (Leishmania braziliensis, L. guyanensis, and L. mexicana) and dogs (L. guyanensis and L. mexicana). The predominant sand fly species found were those from the Verrucarum group (infected with L. mexicana) and Lutzomyia migonei (infected with L. guyanensis and L. mexicana). MAIN CONCLUSIONS We show that Lu. migonei may be the putative vector in two ACL epidemiological cycles, involving L. guyanensis and L. mexicana. We also report for the first time the presence of L. guyanensis in domestic animals.

Has the Earth's sixth mass extinction already arrived?

Palaeontologists characterize mass extinctions as times when the Earth loses more than three-quarters of its species in a geologically short interval, as has happened only five times in the past 540 million years or so. Biologists now suggest that a sixth mass extinction may be under way, given the known species losses over the past few centuries and millennia. Here we review how differences between fossil and modern data and the addition of recently available palaeontological information influence our understanding of the current extinction crisis. Our results confirm that current extinction rates are higher than would be expected from the fossil record, highlighting the need for effective conservation measures.

Genetic variability of Trypanosoma cruzi TcI isolates from rural and urban areas of Venezuela.

BACKGROUND & OBJECTIVES: Several studies have demonstrated genetic heterogeneity in populations of Trypanosoma cruzi that allowed the identification of six different discrete typing units (DTU) classified as TcI, TcII, TcIII, TcIV, TcV and TcVI. Furthermore, some characterization studies have described genetic variability within TcI isolates from endemic regions. The objective of the present study was to analyze Venezuelan T. cruzi isolates, obtained from triatomine-vectors, mammal-hosts including infected humans, detected in both rural and urban areas from diverse geographic origins. METHODS: Molecular characterization of 44 Venezuelan T. cruzi isolates, obtained from triatomine-vectors, mammalian hosts and human patients from both rural and urban areas of different geographic origins, were carried out. Samples were analyzed by PCR amplification of the intergenic region of the mini-exon gene, 24Sα rDNA and 18S rDNA, followed by sequencing of the amplification products. RESULTS: The TcI amplification pattern was found in 42 out of 44 (95.5%) isolates; a TcIII strain and one possible TcIV were also found. The sequence analysis of the TcI Venezuelan isolates showed genetic variability among them. Urban isolates formed a homogeneous group, with differences in their sequences, when compared to rural isolates. INTERPRETATION & CONCLUSION: The results showed genetic heterogeneity in Venezuelan TcI strains, probably in response to different environmental conditions.

Chagas Disease and Leishmaniasis, Sympatric Zoonoses Present in Human from Rural Communities of Venezuela.

PURPOSE: Trypanosoma cruzi and Leishmania spp. coexist in several endemic areas, and there are few studies of Chagas disease and leishmaniasis coinfection worldwide; for this reason, the objective of this work was to determine the Chagas disease and leishmaniasis coinfection in several rural communities co-endemic for these diseases. METHODS: A total of 1107 human samples from six co-endemic rural communities of Cojedes state, Venezuela, were analyzed. Serum samples were evaluated by ELISA, indirect hemagglutination, and indirect immunofluorescence for Chagas disease diagnosis, and individuals were evaluated for leishmaniasis by leishmanin skin test (LST). Approximately, 30% of the individuals were also analyzed by PCR (blood clot samples) for T. cruzi and for Leishmania spp. RESULTS: The 14.7% of the individuals were positive to Trypanosoma cruzi infection by serology, and 25.8% were positive to Leishmania spp. current or past infection by LST. Among the group with PCR results, 7.8% were positive for T. cruzi, and 9.4% for Leishmania spp. The coinfection T. cruzi/Leishmania spp. was 6.5%. The T. cruzi DTUs of the positive blood clot samples were TcI, revealed using the molecular markers: (i) intergenic region of the miniexon, (ii) D7 divergent domain of the 24Sα rDNA, (iii) size-variable domain of the 18S rDNA, and (iv) hsp60-PCR-RFLP (EcoRV). The Leishmania species identified were L. (Leishmania) mexicana and L. (Viannia) braziliensis. CONCLUSION: A high prevalence was found for T. cruzi and Leishmania spp. single and coinfections in almost all communities studied, being these results of relevance for the implementation of control programs in co-endemic areas.

[Comparison between immunological and molecular techniques for the diagnosis of Chagas disease]. / Comparación entre técnicas inmunológicas y moleculares para el diagnóstico de la enfermedad de Chagas.

INTRODUCTION: Chagas disease is caused by the parasite Trypanosoma cruzi. The disease involves an acute and chronic phases. The diagnosis has limitations, both in parasitological and immunological techniques. Molecular assays are an alternative, but these must be evaluated to determine its diagnostic usefulness. The aim of this study was to compare the effectiveness of immunological techniques with molecular assays in the diagnosis of Chagas disease in its different phases. METHODS: The immunological techniques used were ELISA, HAI and IFI and the molecular techniques used were PCR for amplification of kinetoplast minicircles, and satellite DNA of T. cruzi. Thirty-nine blood samples from patients in the acute phase of Chagas disease, and 42 samples from patients in the chronic phase were evaluated. In addition, 20 samples from healthy individuals and 10 patients with other diseases were also studied. RESULTS: With immunological techniques were positive, 69.2% of samples from patients in the acute phase, while in the chronic phase were positive 95.2%. Using molecular techniques 79.5% of samples from patients in the acute phase were positive, while 23.8% of the samples from patients in the chronic phase were positive. None of the samples from healthy individuals was positive for any technique, while two samples from patients with other diseases were positive by the immunological assays. CONCLUSIONS: The diagnostic efficacy of molecular techniques is high in the acute phase of Chagas disease, while in the chronic phase the immunological techniques are more effective.

CD8+ lymphocytes do not impact SIV reservoir establishment under ART.

Persistence of the human immunodeficiency virus type-1 (HIV-1) latent reservoir in infected individuals remains a problem despite fully suppressive antiretroviral therapy (ART). While reservoir formation begins during acute infection, the mechanisms responsible for its establishment remain unclear. CD8+ T cells are important during the initial control of viral replication. Here we examined the effect of CD8+ T cells on formation of the latent reservoir in simian immunodeficiency virus (SIV)-infected macaques by performing experimental CD8+ depletion either before infection or before early (that is, day 14 post-infection) ART initiation. We found that CD8+ depletion resulted in slower decline of viremia, indicating that CD8+ lymphocytes reduce the average lifespan of productively infected cells during acute infection and early ART, presumably through SIV-specific cytotoxic T lymphocyte (CTL) activity. However, CD8+ depletion did not change the frequency of infected CD4+ T cells in the blood or lymph node as measured by the total cell-associated viral DNA or intact provirus DNA assay. In addition, the size of the persistent reservoir remained the same when measuring the kinetics of virus rebound after ART interruption. These data indicate that during early SIV infection, the viral reservoir that persists under ART is established largely independent of CTL control.

Diagnostic epitope variability within Taenia solium 8 kDa antigen family: implications for cysticercosis immunodetection.

To study diagnostic epitopes within the Taenia solium 8 kDa antigen family, six overlapping synthetic peptides from an 8 kDa family member (Ts8B2) were synthesized and evaluated by ELISA and MABA with sera from patients with neurocysticercosis (NCC), from infected pigs and from rabbits immunized with recombinant Ts8B2 protein. The pre-immune rabbit sera and the Ts8B2 recombinant protein served as negative and positive controls, respectively. A similar analysis was done with the already described antigenic peptides from another member of the 8 kDa family, highly similar to Ts8B2, the CyDA antigen. Surprisingly, neither the Ts8B2 peptides nor the CyDA peptides were recognized by infected human and porcine sera. However, the entire Ts8B2 recombinant, as well as amino and carboxy-terminal halves were recognized by the positive serum samples. The observed lack of recognition of linear Ts8B2 peptides suggests that the principal serological response to the Ts8B2 family is focused on conformational epitopes in contrast to the previously observed antigenicity of the CyDA peptides. This differential antigenicity of 8 kDa family peptides could be related with parasite antigenic variability. The fact that rabbits experimentally immunized with Ts8B2 did make anti-peptide antibodies to peptides Ts8B2-6 and CyDA-6, located in the carboxy-terminal region demonstrated that the Ts8B2 peptides are not intrinsically non-immunogenic.

Evaluation of commercial kits for the immunological and molecular diagnosis of Chagas disease in endemic areas of Venezuela.

INTRODUCTION: The sensitivity and specificity of diagnostic techniques for Chagas disease depend largely on the antigens and targets used and on the immune response and characteristics of the infection of the population where it is applied, hence the need for evaluation of the diagnostic techniques available in a given area. So, the objective of this work was to evaluate two commercial kits for the immunological and molecular diagnosis of Chagas disease in endemic areas of Venezuela. METHODS: The evaluated kits were: Chagas ELISA IgG+IgM® and Speed Oligo Chagas® (Vircell®, Granada, Spain). They were evaluated with 129 samples (35 from patients in the acute phase, 33 in the chronic phase, 31 from patients with other diseases, and 30 from healthy individuals). The results were compared with those obtained in the conventional ELISA and PCR-satellite DNA tests for Trypanosoma cruzi. RESULTS: With Chagas ELISA IgG+IgM® a sensitivity of 94.1% and specificity of 93.4% were obtained, with Speed Oligo Chagas® a sensitivity of 92.6% and specificity of 100% were achieved, values similar to those showed by conventional ELISA and satDNA-PCR. CONCLUSION: The sensitivity and specificity of the commercial kits evaluated make them suitable for the diagnosis of Chagas disease in endemic areas of Venezuela.

Standardization of the PCR Technique for the Detection of the Toxoplasma gondii B1 Gene in Meat and Water Samples and Cloning of the Product for Use as Control.

INTRODUCTION: Toxoplasmosis is caused by the parasite Toxoplasma gondii. The infection is generally asymptomatic and the most severe cases occur in immunosuppressed patients. The main route of transmission is the ingestion of water or food contaminated with cysts of the parasite. The objective of this work was the standardization of the PCR for the detection of the T. gondii B1 gene in meat and water samples and cloning of the product for use as a control. METHODS: The optimal reaction conditions of the different components of the PCR were determined and the technique was used to detect DNA from meat and water samples. Bands were purified and cloned into a pGEM-T-Easy vector and used as a control in the PCR. RESULTS: Optimal PCR conditions were; 100 µM dNTP, 0.4 µM primers, and 0.5 U Taq polymerase. The product obtained from the PCR was cloned with a simple cloning strategy with efficient results. With the standardized PCR and using the cloned DNA as a control, T. gondii DNA was detected in 90% of the positives samples of meat and water and there was no amplification in the negative samples. CONCLUSIONS: The PCR assay standardized in this study was demonstrated to be an effective technique to detect T. gondii DNA in meat and water samples. The cloning of PCR product and its application as a control in molecular diagnosis of toxoplasmosis might improve the reproducibility of this method and avoid the use of patient samples or cultures, which present several limitations.

Infections and Coinfections by Trypanosomatid Parasites in a Rural Community of Venezuela.

INTRODUCTION: Trypanosoma cruzi, Trypanosoma rangeli and Leishmania spp. are parasites that coexist in several endemic areas. The identification of these parasites in hosts is important for the control programs. METHODS: 216 samples from human blood (101), blood of other mammals (45) and triatomine intestinal content and hemolymph (70), from an endemic area of Venezuela, were analysed. The samples were evaluated by; serology (only humans) and PCR for T. cruzi in human, other mammals and triatomines, PCR for T. rangeli in mammals-including human and triatomines and PCR for Leishmania in mammals-including human. RESULTS: The 9.9% of the human samples were positive for T. cruzi by serology, 11.9% by PCR, 4% for T. rangeli PCR and none for Leishmania spp. PCR. 60% of the samples of other mammals showed DNA amplification for T. cruzi, 42.2% for T. rangeli and 4.4% for Leishmania spp. 61.4% of the triatomine samples showed DNA amplification for T. cruzi and 10% for T. rangeli. CONCLUSIONS: High T. cruzi infection was detected in mammals and triatomines compared with T. rangeli. Low leishmanial infection was detected in other mammals. It is the first time that T. cruzi/T. rangeli coinfection, in humans, Canis familiaris (dog), and Bos Taurus (cow), were reported world-wide, and that this coinfection was described in Tamandua tetradactyla (anteater) from Venezuela. The coinfection T. cruzi/T. rangeli in mammals-including humans and triatomines, and coinfection T. cruzi/Leishmania spp. in non-human mammals, show the risk for trypanosomic zoonoses in this endemic area.

Multiple-bead assay for the differential serodiagnosis of neglected human cestodiases: Neurocysticercosis and cystic echinococcosis.

BACKGROUND: Neurocysticercosis (NCC), and cystic echinococcosis (CE) are two neglected diseases caused by cestodes, co-endemic in many areas of the world. Imaging studies and serological tests are used in the diagnosis of both parasitic diseases, but cross-reactions may confound the results of the latter. The novel multiplex bead-based assay with recombinant antigens has been reported to increases the diagnostic accuracy of serological techniques. METHODOLOGY: We set-up an immunoassay based on the multiplex bead-based platform (MBA), using the rT24H (against Cysticercus cellulosae, causing cysticercosis) and r2B2t (against Echinococcus granulosus sensu lato, causing CE) recombinant antigens, for simultaneous and differential diagnosis of these infections. The antigens were tested on 356 sera from 151 patients with CE, 126 patients with NCC, and 79 individuals negative for both diseases. Specificity was calculated including sera from healthy donors, other neurological diseases and the respective NCC or CE sera counterpart. The diagnostic accuracy of this assay was compared with two commercial ELISA tests, Novalisa and Ridascreen, widely used in the routine diagnosis of cysticercosis and CE, respectively. MAIN FINDINGS: For the diagnosis of NCC, sensitivity ranged from 57.94-63.49% for the rT24H-MBA, and 40.48-46.03% for Novalisa ELISA depending on exclusion or inclusion of sera having equivocal results on ELISA from the analysis; specificities ranged from 90.87-91.30% and 70.43-76.96%, respectively. AUC values of the ROC curve were 0.783 (rT24H) and 0.619 (Novalisa) (p-value < 0.001). For the diagnosis of CE, the sensitivity of the r2B2t-MBA ranged from 68.87-69.77% and of Ridascreen ELISA from 50.00-57.62%; specificities from 92.47-92.68% and from 74.15-80.98%, respectively. AUC values were 0.717 and 0.760, respectively. CONCLUSIONS/SIGNIFICANCE: Overall, the recombinant antigens tested with the bead-based technology showed better diagnostic accuracy than the commercial assays, particularly for the diagnosis of NCC. The possibility of testing the same serum sample simultaneously for the presence of antibodies against both antigens is an added value particularly in seroprevalence studies for cysticercosis linked to control programs in endemic areas where these two parasites coexist.

PI4K2A deficiency causes innate error in intracellular trafficking with developmental and epileptic-dyskinetic encephalopathy.

OBJECTIVE: Intracellular signaling networks rely on proper membrane organization to control an array of cellular processes such as metabolism, proliferation, apoptosis, and macroautophagy in eukaryotic cells and organisms. Phosphatidylinositol 4-phosphate (PI4P) emerged as an essential regulatory lipid within organelle membranes that defines their lipid composition and signaling properties. PI4P is generated by four distinct phosphatidylinositol 4-kinases (PI4K) in mammalian cells: PI4KA, PI4KB, PI4K2A, PI4K2B. Animal models and human genetic studies suggest vital roles of PI4K enzymes in development and function of various organs, including the nervous system. Bi-allelic variants in PI4KA were recently associated with neurodevelopmental disorders (NDD), brain malformations, leukodystrophy, primary immunodeficiency, and inflammatory bowel disease. Here, we describe patients from two unrelated consanguineous families with PI4K2A deficiency and functionally explored the pathogenic mechanism. METHODS: Two patients with PI4K2A deficiency were identified by exome sequencing, presenting with developmental and epileptic-dyskinetic encephalopathy. Neuroimaging showed corpus callosum dysgenesis, diffuse white matter volume loss, and hypoplastic vermis. In addition to NDD, we observed recurrent infections and death at toddler age. We further explored identified variants with cellular assays. RESULTS: This clinical presentation overlaps with what was previously reported in two affected siblings with homozygous nonsense PI4K2A variant. Cellular studies analyzing these human variants confirmed their deleterious effect on PI4K2A activity and, together with the central role of PI4K2A in Rab7-associated vesicular trafficking, establish a link between late endosome-lysosome defects and NDD. INTERPRETATION: Our study establishes the genotype-phenotype spectrum of PI4K-associated NDD and highlights several commonalities with other innate errors of intracellular trafficking.

[Ocular manifestations of toxocariasis in schoolchildren from the state from the Anzoátegui state in Venezuela]. / Manifestaciones oculares de la toxocariasis en escolares del estado Anzoátegui en Venezuela.

The objective of this study was to determine ocular manifestations of toxocariasis in schoolchildren. A study was conducted in two schools in the Anzoátegui state in Venezuela in 2019. The ELISA test was used to determine IgG antibodies against Toxocara spp. The families completed a questionnaire, and the children were clinically evaluated by pediatricians and ophthalmologists. 118 children participated, 18.6% presented anti-Toxocara spp. The clinical manifestations with a statistically significant association were allergic reactions, epiphora, and decreased visual acuity. The ophthalmological evaluation found keratitis, uveitis, iritis, retinal granuloma, endophthalmitis, amaurosis, leukocoria, retinal detachment and endotropia. The findings show a high frequency of eye disease in children with toxocariasis from a state of Venezuela.

El objetivo de este estudio fue determinar manifestaciones oculares de la toxocariasis en escolares. Se realizó un estudio en dos escuelas del estado Anzoátegui en Venezuela en el 2019. Se empleó la prueba de ELISA para determinar los anticuerpos IgG contra Toxocara spp. Las familias completaron un cuestionario y los niños fueron evaluados clínicamente por pediatras y oftalmólogos. Participaron 118 niños, el 18,6% presentó anticuerpos anti-Toxocara spp. Las manifestaciones clínicas con asociación estadísticamente significativa fueron las reacciones alérgicas, epífora y disminución de la agudeza visual. En la evaluación oftalmológica se encontró queratitis, uveítis, iritis, granuloma retiniano, endoftalmitis, amaurosis, leucocoria, desprendimiento de retina y endotropía. Los hallazgos muestran una alta frecuencia de enfermedad ocular en niños con toxocariasis de un estado de Venezuela.

Utility of a Fluid Library with Samples of Humans, Reservoirs and Vectors Collected in Filter Paper, for Retrospective Diagnosis of American Trypanosomiasis in Endemic Areas of Venezuela.

INTRODUCTION: We define a fluid library as a library of samples of different biological fluids (from humans, animals or vectors) collected and properly stored on filter paper, which allows retrospective studies, especially of diagnosis or detection of infectious agents in these samples, using different techniques. The objective of this work was the retrospective diagnosis of American trypanosomiasis by PCR in a Venezuelan endemic area using a fluid library. METHODS: A fluid library with samples that had been collected on filter paper, 5 years ago, was used for the detection of Trypanosoma cruzi DNA. 165 blood samples of humans, 30 samples of 25 animals (Didelphis marsupialis, Canis familiaris, Equus asinus and Felis catus) and 8 samples of vectors from endemic areas of Anzoátegui state, were analysed by PCR. RESULTS: The results revealed that 16.4% of the humans samples were positive, 11.1% of those detected positive were children younger than 10 years old, and 26.72% young people aged 11-20 years, suggesting that T. cruzi infection has been active for the past two decades. 56% of the animal samples showed amplification; Didelphis marsupialis 66%, Canis familiaris 54.5%, Equus asinus 50%, and Felis catus 33.3%. On the other hand, positivity (50%) was detected in the studied vectors, of which the 3 most important species in Venezuela (Rhodnius prolixus, Triatoma maculata and Panstrongylus geniculatus) were involved. CONCLUSIONS: The PCR using a fluid library allowed the detection of T. cruzi DNA in old samples from the three host of the epidemiological chain, suggesting that retrospective diagnosis can be made through this strategy and demonstrate that there has been active transmission, which helps to clarify the epidemiological situation in areas where there are no previous reports.

First molecular detection of Trypanosoma cruzi, T. rangeli and Leishmania spp. in capybaras.

Hydrochoerus hydrochaeris (capybara), is a widely distributed rodent in Latin America, with exploitation for food purposes and also used in leather industry products. The infection of this rodent by trypanosomatids may not be detected by parasitological methods, due to low parasitemias. The Capybaras blood samples from the Apure State were collected on filter paper, DNA was extracted and PCR was performed. The PCR technique was used for the detection of Trypanosoma cruzi satellite and kinetoplast DNA, T. rangeli miniexon, T. evansi RIME sequence, and DNA encoding ribosomal RNA and internal transcribed spacer 1 from Leishmania spp. Of the 16 evaluated samples, 12 (75%) were positive for T. cruzi, two for T. rangeli (12.5%), one for Leishmania spp. (6.3%) and none for T. evansi. Regarding coinfection, the two specimens infected with T. rangeli were also infected with T. cruzi (12.5%) and the positive sample for Leishmania spp. was also infected with T. cruzi (6.3%). The results shown in this study represent the first finding of T. cruzi infection, detected by molecular methods, world-wide and the first time that T. rangeli and Leishmania spp. have been found in capybaras. In addition, we report coinfections by T. cruzi/T. rangeli and T. cruzi/Leishmania spp. in H. hydrochaeris for the first time world-wide. Capybaras are widely managed as a source of animal protein, the results obtained require evaluating their possible role as a reservoir in trypanosomiasis and leishmaniasis. A 'One Health' approach through combination of ecological, veterinary and human health including the diagnosis and treatment of diseases of both humans and animals is essential for the development of more successful health programs.