First external quality assurance program for bloodstream Real-Time PCR monitoring of treatment response in clinical trials of Chagas disease

Real-Time PCR (qPCR) testing is recommended as both a diagnostic and outcome measurement of etiological treatment in clinical practice and clinical trials of Chagas disease (CD), but no external quality assurance (EQA) program provides performance assessment of the assays in use. We implemented an EQA system to evaluate the performance of molecular biology laboratories involved in qPCR based follow-up in clinical trials of CD. An EQA program was devised for three clinical trials of CD: the E1224 (NCT01489228), a pro-drug of ravuconazole; the Sampling Study (NCT01678599), that used benznidazole, both conducted in Bolivia; and the CHAGASAZOL (NCT01162967), that tested posaconazole, conducted in Spain. Four proficiency testing panels containing negative controls and seronegative blood samples spiked with 1, 10 and 100 parasite equivalents (par. eq.)/mL of four Trypanosoma cruzi stocks, were sent from the Core Lab in Argentina to the participating laboratories located in Bolivia and Spain. Panels were analyzed simultaneously, blinded to sample allocation, at 4-month intervals. In addition, 302 random blood samples from both trials carried out in Bolivia were sent to Core Lab for retesting analysis. The analysis of proficiency testing panels gave 100% of accordance (within laboratory agreement) and concordance (between laboratory agreement) for all T. cruzi stocks at 100 par. eq./mL; whereas their values ranged from 71 to 100% and from 62 to 100% at 1 and 10 par. eq./mL, respectively, depending on the T. cruzi stock. The results obtained after twelve months of preparation confirmed the stability of blood samples in guanidine-EDTA buffer. No significant differences were found between qPCR results from Bolivian laboratory and Core Lab for retested clinical samples. This EQA program for qPCR analysis of CD patient samples may significantly contribute to ensuring the quality of laboratory data generated in clinical trials and molecular diagnostics laboratories of CD

Prospective multicenter evaluation of real time PCR Kit prototype for early diagnosis of congenital Chagas disease

Background: Current algorithm for Congenital Chagas Disease (cCD) diagnosis is unsatisfactory due to low sensitivity of the parasitological methods. Moreover, loss to follow-up precludes final serodiagnosis after nine months of life in many cases. A duplex TaqMan qPCR kit for Trypanosoma cruzi DNA amplification was prospectively evaluated in umbilical cord (UCB) and peripheral venous blood (PVB) of infants born to CD mothers at endemic and non-endemic sites of Argentina. Methods: We enrolled and followed-up 370 infants; qPCR was compared to gold-standard cCD diagnosis following studies of diagnostic accuracy guidelines. Findings: Fourteen infants (3·78%) had cCD. The qPCR sensitivity and specificity were higher in PVB (72·73%, 99·15% respectively) than in UCB (66·67%, 96·3%). Positive and negative predictive values were 80 and 98·73% and 50 and 98·11% for PVB and UCB, respectively. The Areas under the Curve (AUC) of ROC analysis for qPCR and micromethod (MM) were 0·81 and 0·67 in UCB and 0·86 and 0·68 in PVB, respectively. Parasitic loads ranged from 37·5 to 23,709 parasite equivalents/mL. Discrete typing Unit Tc V was identified in five cCD patients and in six other cCD cases no distinction among Tc II, Tc V or Tc VI was achieved. Interpretation: This first prospective field study demonstrated that qPCR was more sensitive than MM for early cCD detection and more accurate in PVB than in UCB. Its use, as an auxiliary diagnostic tool to MM will provide more accurate records on cCD incidence. Funding: FITS SALUD 001-CHAGAS (FONARSEC, MINCyT, Argentina) to the Public-Private Consortium (INGEBI-CONICET, INP-ANLIS MALBRAN and Wiener Laboratories); ERANET-LAC-HD 328 to AGS and PICT 2015-0074 (FONCYT, MinCyT) to AGS and FA.Fil: Benatar, Alejandro Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Danesi, Emmaría. Dirección Nacional de Instituto de Investigación.Administración Nacional de Laboratorios e Institutos de Salud "Dr. Carlos G. Malbrán"; ArgentinaFil: Besuschio, Susana Alicia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Bortolotti, Santiago. Wiener Laboratorios SAIC; ArgentinaFil: Cafferata, María Luisa. Instituto de Efectividad Clínica y Sanitaria; ArgentinaFil: Ramirez Gomez, Juan Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Lopez Albizu, Maria Constanza. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud “Dr. C. G. Malbrán”. Instituto Nacional de Parasitología "Dr. Mario Fatala Chaben”; ArgentinaFil: Scollo, Karenina. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud “Dr. C. G. Malbrán”. Instituto Nacional de Parasitología "Dr. Mario Fatala Chaben”; ArgentinaFil: Baleani, María. Wiener Laboratorios SAIC; ArgentinaFil: Lara, Laura. Instituto de Maternidad y Ginecología ''Nuestra Señora de las Mercedes''; ArgentinaFil: Agolti, Gustavo. Gobierno de la Provincia de Chaco. Hospital Julio César Perrando; ArgentinaFil: Seu, Sandra. Gobierno de la Provincia de Santiago del Estero. Hospital Regional Dr. Ramón Carrillo; ArgentinaFil: Adamo, Elsa. Provincia de Santiago del Estero. Centro Integral de Salud La Banda; ArgentinaFil: Lucero, Raul Horacio. Universidad Nacional del Nordeste. Instituto de Medicina Regional; ArgentinaFil: Irazu, Lucía. Dirección Nacional de Instituto de Investigación.Administración Nacional de Laboratorios e Institutos de Salud "Dr. Carlos G. Malbrán"; ArgentinaFil: Rodriguez, Marcelo. Dirección Nacional de Instituto de Investigación.Administración Nacional de Laboratorios e Institutos de Salud "Dr. Carlos G. Malbrán"; ArgentinaFil: Poeylaut Palena, Andrés Alberto. Wiener Laboratorios SAIC; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Longhi, Silvia Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Esteva, Mónica Inés. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud “Dr. C. G. Malbrán”. Instituto Nacional de Parasitología "Dr. Mario Fatala Chaben”; ArgentinaFil: Althabe, Fernando. Instituto de Efectividad Clínica y Sanitaria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rojkin, Federico. Wiener Laboratorios SAIC; ArgentinaFil: Bua, Jacqueline Elena. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud “Dr. C. G. Malbrán”. Instituto Nacional de Parasitología "Dr. Mario Fatala Chaben”; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Sosa-Estani, Sergio Alejandro. Instituto de Efectividad Clínica y Sanitaria; Argentina. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud “Dr. C. G. Malbrán”. Instituto Nacional de Parasitología "Dr. Mario Fatala Chaben”; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Schijman, Alejandro Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Congenital Chagas Disease Study Group. No especifíca

The classical Bordetella species and MALDI-TOF technology: a brief experience

Fil: Zintgraff, Jonathan. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Bacteriología. Servicio de Bacteriología Clínica; Argentina.Fil: Irazu, Lucía. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Bacteriología. Servicio de Bacteriología Clínica; Argentina.Fil: Lara, Claudia. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Bacteriología. Servicio de Bacteriología Clínica; Argentina.Fil: Rodriguez, Marcelo. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Bacteriología. Servicio de Bacteriología Clínica; Argentina.Fil: Santos, Mauricio. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Bacteriología. Servicio de Bacteriología Clínica; Argentina.The aim of this work was to evaluate and optimize the identification of Bordetella pertussis, Bordetella parapertussis and Bordetella bronchiseptica (usually known as the classical Bordetella species) using Bruker Biotyper matrix-assisted laser desorption ionization/time-of-flight mass spectrometry (MALDI-TOF MS)

Contribution of the PCR assay to the diagnosis of Mansonella ozzardi in endemic areas of Argentina

Fil: Degese, María Fernanda. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Parasitología; Argentina.Fil: Cabrera, Marta Graciela. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Parasitología; Argentina.Fil: Krivokapich, Silvio. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Parasitología; Argentina.Fil: Irazu, Lucia. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Parasitología; Argentina.Fil: Rodríguez, Marcelo. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Parasitología; Argentina.Fil: Guarnera, Eduardo. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Parasitología; 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

Duplex realtime PCR method for Epstein-Barr virus and human DNA quantification: its application for post-transplant lymphoproliferative disorders detection

INTRODUCTION: The quantification of circulating Epstein-Barr virus (EBV) DNA is used to monitor transplant patients as an early marker of Post-Transplant Lymphoproliferative Disorders (PTLD). So far no standardized methodology exists for such determination.OBJECTIVE: Our purpose was to develop and validate a real-time PCR assay to quantify EBV DNA in clinical samples from transplant recipients.METHODS: A duplex real-time PCR method was developed to amplify DNA from EBV and from a human gene. The EBV load was determined in peripheral blood mononuclear cells (PBMC), plasma and oropharyngeal tissue from 64 non-transplanted patients with lymphoid-hypertrophy (Non-Tx), 47 transplant recipients without PTLD (Tx), 54 recipients with PTLD (Tx-PTLD), and 66 blood donors (BD). WinPEPI, version 11.14 software was used for statistical analysis.RESULTS:Analytical validation: the intra and inter-assays variation coefficients were less than 4.5% (EBV-reaction) and 3% (glyceraldehyde 3-phosphate dehydrogenase - GAPDH reaction). Linear ranges comprised 107-10 EBV genome equivalents (gEq) (EBV-reaction) and 500,000-32 human gEq (GAPDH-reaction). The detection limit was 2.9 EBV gEq (EBV-reaction). Both reactions showed specificity. Application to clinical samples: higher levels of EBV were found in oropharyngeal tissue from transplanted groups with and without PTLD, compared to Non-Tx (p < 0.05). The EBV load in PBMC from the groups of BD, Non-Tx, Tx and Tx-PTLD exhibited increasing levels (p < 0.05). In BD, PBMC and plasma, EBV loads were undetectable.CONCLUSIONS: The performance of the assay was suitable for the required clinical application. The assay may be useful to monitor EBV infection in transplant patients, in particular in laboratories from low-income regions that cannot afford to use commercial assays

Contribution of the PCR assay to the diagnosis of Mansonella ozzardi in endemic areas of Argentina

Fil: Degese, María Fernanda. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Parasitología; Argentina.Fil: Cabrera, Marta Graciela. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Parasitología; Argentina.Fil: Krivokapich, Silvio. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Parasitología; Argentina.Fil: Irazu, Lucia. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Parasitología; Argentina.Fil: Rodríguez, Marcelo. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Parasitología; Argentina.Fil: Guarnera, Eduardo. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Parasitología; 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

Utility of platforms Viteks MS and Microflex LT for the identification of complex clinical isolates that require molecular methods for their taxonomic classification

Fil: Rocca, María Florencia. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Bacteriología. Servicio de Bacteriología Especial; Argentina.Fil: Barrios, Rubén. Laboratorio de Bacteriología, Hospital Italiano de Buenos Aires, Ciudad Autónoma de Buenos Aires; Argentina.Fil: Zintgraff, Jonathan. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Bacteriología. Servicio de Bacteriología Clínica; Argentina.Fil: Martínez, Claudia. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Bacteriología. Servicio de Bacteriología Especial; Argentina.Fil: Irazu, Lucía. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas; Argentina.Fil: Vay, Carlos. Instituto de Fisiopatología y Bioquímica Clínica, Hospital de Clínicas José de San Martín, Facultad de Farmacia y Bioquímica, Ciudad Autónoma de Buenos Aires; Argentina.Fil: Prieto, Mónica A. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Bacteriología. Servicio de Bacteriología Especial; Argentina.Mass spectrometry has revolutionized the clinical microbiology field in America's and Europe's industrialized countries, for being a fast, reliable and inexpensive technique. Our study is based on the comparison of the performance of two commercial platforms, Microflex LT (Bruker Daltonics, Bremen, Germany) and Vitek MS (bioMérieux, Marcy l´Etoile, France) for the identification of unusual and hard-to-diagnose microorganisms in a Reference Laboratory in Argentina. During a four-month period (February-May 2018) the diagnostic efficiency and the concordance between both systems were assessed, and the results were compared with the polyphasic taxonomic identification of all isolates. The study included 265 isolates: 77 Gram-Negative Bacilli, 33 Gram-Positive Cocci, 40 Anaerobes, 35 Actinomycetales, 19 Fastidious Microorganisms and 61 Gram-Positive Bacilli. All procedures were practiced according to the manufacturer's recommendations in each case by duplicate, and strictly in parallel. Other relevant factors, such as the utility of the recommended extraction protocols, reagent stability and connectivity were also evaluated. Both systems correctly identified the majority of the isolates to species and complex level (82%, 217/265). Vitex MS achieved a higher number of correct species-level identifications between the gram-positive microorganisms; however, it presented greater difficulty in the identification of non-fermenting bacilli and a higher number of incorrect identifications when the profile of the microorganism was not represented in the commercial database. Both platforms showed an excellent performance on the identification of anaerobic bacteria and fastidious species. Both systems enabled the fast and reliable identification of most of the tested isolates and were shown to be very practical for the user

Neotropical Zoonotic Parasites in Bush Dogs (Speothos venaticus) from Upper Paraná Atlantic Forests in Misiones, Argentina

Fil: Vizcaychipi, Katherina A. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Parasitología. Servicio de Inmunología Parasitaria; Argentina.Fil: Rinas, Miguel. Ministerio de Ecología y Recursos Naturales Renovables, Misiones; Argentina.Fil: Irazu, Lucia. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Parasitología. Servicio de Inmunología Parasitaria; Argentina.Fil: Miyagi, Adriana. ANLIS Dr.C.G.Malbrán. Unidad Operativa Centro de Contención Biológica; Argentina.Fil: Argüelles, Carina F. GIGA IBS Nodo Posadas (UNaM-CONICET), Posadas; Argentina.Fil: DeMatteo, Karen E. Washington University. Department of Biology. Saint Louis Zoo WildCare Institute, San Luis; Misuri.Wildlife remains an important source of zoonotic diseases for the most vulnerable groups of humans, primarily those living in rural areas or coexisting with forest. The Upper Paraná Atlantic forest of Misiones, Argentina is facing ongoing environmental and anthropogenic changes, which affect the local biodiversity, including the bush dog (Speothos venaticus), a small canid considered Near Threatened globally and Endangered locally. This project aimed to expand the knowledge of zoonotic parasites present in the bush dog and the potential implications for human health and conservation medicine. From May to August 2011, a detection dog located 34 scats that were genetically confirmed as bush dog and georeferenced to northern Misiones. Of these 34 scats, 27 had sufficient quantity that allowed processing for zoonotic parasites using morphological (sedimentation and flotation) and antigen (coproantigen technique) analyses. Within these 27 scats, we determined that the parasitic prevalence was 63.0% (n = 17) with 8 (47.1%) having mixed infections with 2-4 parasitic genera. No significant differences (p > 0.05) between sampling areas, sex, and parasite taxa were found. We were able to summarize the predominant nematodes (Ancylostoma caninum, Toxocara canis, and Lagochilascaris spp.), cestodes (Taenia spp. and Spirometra spp.), and apicomplexa (Cystoisospora caninum) found in these bush dogs. With the copro-ELISA technique, 14.8% (n = 4) of the samples were positive for Echinococcus spp. This study represents the first comprehensive study about parasitic fauna with zoonotic potential in the free-ranging bush dog. This information combined with the innovative set of techniques used to collect the samples constitute a valuable contribution that can be used in control programs, surveillance of zoonotic diseases, and wildlife conservation, both regionally and across the bush dog's broad distribution

Utility of platforms Viteks MS and Microflex LT for the identification of complex clinical isolates that require molecular methods for their taxonomic classification

Fil: Rocca, María Florencia. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Bacteriología. Servicio de Bacteriología Especial; Argentina.Fil: Barrios, Rubén. Laboratorio de Bacteriología, Hospital Italiano de Buenos Aires, Ciudad Autónoma de Buenos Aires; Argentina.Fil: Zintgraff, Jonathan. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Bacteriología. Servicio de Bacteriología Clínica; Argentina.Fil: Martínez, Claudia. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Bacteriología. Servicio de Bacteriología Especial; Argentina.Fil: Irazu, Lucía. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas; Argentina.Fil: Vay, Carlos. Instituto de Fisiopatología y Bioquímica Clínica, Hospital de Clínicas José de San Martín, Facultad de Farmacia y Bioquímica, Ciudad Autónoma de Buenos Aires; Argentina.Fil: Prieto, Mónica A. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Bacteriología. Servicio de Bacteriología Especial; Argentina.Mass spectrometry has revolutionized the clinical microbiology field in America's and Europe's industrialized countries, for being a fast, reliable and inexpensive technique. Our study is based on the comparison of the performance of two commercial platforms, Microflex LT (Bruker Daltonics, Bremen, Germany) and Vitek MS (bioMérieux, Marcy l´Etoile, France) for the identification of unusual and hard-to-diagnose microorganisms in a Reference Laboratory in Argentina. During a four-month period (February-May 2018) the diagnostic efficiency and the concordance between both systems were assessed, and the results were compared with the polyphasic taxonomic identification of all isolates. The study included 265 isolates: 77 Gram-Negative Bacilli, 33 Gram-Positive Cocci, 40 Anaerobes, 35 Actinomycetales, 19 Fastidious Microorganisms and 61 Gram-Positive Bacilli. All procedures were practiced according to the manufacturer's recommendations in each case by duplicate, and strictly in parallel. Other relevant factors, such as the utility of the recommended extraction protocols, reagent stability and connectivity were also evaluated. Both systems correctly identified the majority of the isolates to species and complex level (82%, 217/265). Vitex MS achieved a higher number of correct species-level identifications between the gram-positive microorganisms; however, it presented greater difficulty in the identification of non-fermenting bacilli and a higher number of incorrect identifications when the profile of the microorganism was not represented in the commercial database. Both platforms showed an excellent performance on the identification of anaerobic bacteria and fastidious species. Both systems enabled the fast and reliable identification of most of the tested isolates and were shown to be very practical for the user

Venom yield and its relationship with body size and fang separation of pit vipers from Argentina

Fil: de Roodt, Adolfo R. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Producción de Biológicos; Argentina.Fil: Boyer, Leslie. VIPER Institute and Department of Pathology, College of Medicine, University of Arizona Health Sciences, Tucson, AZ; Estados Unidos.Fil: Lanari, Laura Cecilia, ANLIS Dr.C.G.Malbrán. Instituto Nacional de Producción de Biológicos; Argentina.Fil: Irazu, Lucía. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Parasitología; Argentina.Fil: Laskowicz, Rodrigo Daniel. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Producción de Biológicos; Argentina.Fil: Sabattini, Paula Leticia. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Producción de Biológicos; Argentina.Fil: Damin, Carlos Fabián. First Cathedra of Toxicology, Faculty of Medicine, University of Buenos Aires, Buenos Aires; Argentina.The amount of venom that a snake can inject is related to its body size. The body size is related to head size and to the distance between fangs. To correlate snake body size, distance between fangs and distance between puncture wounds with the venom yield (and consequently with the venom dose potentially injected in a single snakebite), we studied these variables in two species of public health importance in South America, Bothrops (Rhinocerophis) alternatus, and Crotalus durissus terrificus. In all cases a positive correlation was observed between body length, fang separation distance, distance between puncture wounds and venom yield, with a regression coefficient over 0.5 for Bothrops alternatus and over 0.6 for Crotalus durissus terrificus in all cases, being the relation distance between punctures wounds and venom yield of 0.54 and 0.69 respectively. The difference between fang separation and puncture separation was never greater than 30%, with a mean difference around 13%. The strong relationships between body size, fang separation and venom yield may be useful for planning potential venom production in serpentariums. In addition, because puncture mark separation gives an approximate idea of the size of the snake, this provides a rough idea of the size of the snake that produced a bite and the potential amount of venom that could have been injected