Venom Week organizing committee, speakers and poster abstract presenters who have submitted photos and/or bios are below.
Please refer to agenda page for agenda breakdown including additional topics on snake venoms, venomics, venom gland organoids, spider venoms, and clinical presentations.
Craig Woods DVM, MS, MBA (Organizing Chair)
Institute for Future Health, Arizona State University
Veterinary antivenoms & venom diagnostics: projected market size and development costs in the US
I am a clinical researcher and business developer with over 20 years of experience in conducting human and veterinary clinical trials, regulatory affairs (FDA, USDA), technology licensing, due diligence, and contract negotiations. Currently, I am the Director of Infectious Disease and Biosecurity Projects the Institute for Future Health, a joint venture between Arizona State University and the University of Arizona. From 2015-2021, I served as the Director of Midwestern University’s Institute for Healthcare Innovation where I directed the clinical research program with University clinics and external community hospitals; focused on human phase II-IV clinical trials, veterinary clinical studies, and translational research projects. During this time, I also served as a clinical investigator on infectious diseases (anti-infectives, SARS-CoV-2) and comparative & translational studies in the areas of envenomation, oncology, neurology, orthopedics, and cardiovascular disease. From 1998-2015, I was employed in the pharmaceutical industry where I was responsible for leading due diligence and licensing negotiations for various pharmaceuticals, biologics, and medical devices. I have founded several start-up companies which developed and commercialized first-in-class medical technologies. My work in comparative ophthalmology led to the development and approval of a novel subscleral glaucoma implant for humans. However, none of this could have been possible without a supportive family, great mentors and employers, and by standing on the shoulders of those before me.
Sean Bush MD, FACEP (Organizing co-Chair)
WakeMed Health, North Carolina
When it Really is a Spider Bite
Sean P. Bush, M.D., F.A.C.E.P., is an American emergency physician, researcher, author, and presenter on the topic of envenomation (venomous bites and stings). His work has spanned over 25 years and was the subject of the 11-part television series, Venom ER [https://www.youtube.com/watch?v=apvnqrvd9OE]. For his work, Dr. Bush received a certificate of appreciation from the White House Medical Unit and three Wilderness Medical Society Research Awards. He has been integrally involved in clinical trials evaluating the safety of antivenoms for snake and spider bites. In 2022, Dr. Bush was elected President of the North American Society of Toxinology. He also serves on the World Health Organization Snakebite Envenoming Roster of Experts and on the Data Safety Monitoring Board for an international clinical trial evaluating the safety and efficacy of an oral medication for snakebites. He is affiliated with the Asclepius Snakebite Foundation and plans to travel to Guinea this June for the opening of their snakebite clinic and to continue his work in snakebite challenged regions of the world. He is also the father of two thriving young people (in his words) “first and foremost.”
Michael Schaer DVM, DACVECC, DACVIM (Organizing co-Chair)
Professor Emeritus, College of Veterinary Medicine, University of Florida
Prospective Analysis of 95 Pit Viper Envenomations in Northcentral Florida
Michael Schaer received his D.V.M. degree from the University of Illinois in 1970. He then went to the Animal Medical Center (AMC) in New York City where he served as an intern and then as a medicine resident between 1970-73. After the residency, he remained at the AMC until 1977 before entering private small animal practice in New Jersey until late 1978 at which time he joined the faculty at the Univ. of FL, College of Veterinary Medicine where he has remained until the present time. He has published several papers and book chapters and he has lectured nationally and internationally. Dr Schaer is also the author of five textbooks: Clinical Medicine of the Dog and Cat 1st, 2nd, and 3rd editions and Clinical Signs in Small Animal Medicine, 1st and 2nd editions. At the U of F, Dr. Schaer functions mainly as a clinician and a teacher. He is currently Professor Emeritus and Adjunct Professor in Emergency and Critical Care Medicine, while still doing active teaching in the classroom and in the critical care unit. Dr. Schaer is board certified in internal medicine (ACVIM) and emergency and critical care (ACVECC).
William Hayes PhD (Organizing co-Chair)
Director – Center for Biodiversity and Environmental Studies, Loma Linda University
Presentation Topic – pending
William Hayes PhD is a professor of biology and the director of the Center for Environmental Studies and Stewardship at Loma Linda University, California. He and his students study a variety of venomous animals, including rattlesnakes, spiders, scorpions, and centipedes, focusing especially on their behavioral use of venom and venom composition variation. They also examine the behavior, ecology, and conservation of endangered reptiles and birds, with emphases in the California, Caribbean Islands, and Galapagos Islands biodiversity hotspots. In addition to publications in scientific journals, he has co-edited several volumes, including The Biology of Rattlesnakes, The Biology of Rattlesnakes II, and Iguanas: Biology and Conservation. He has also written articles about environmental stewardship in an effort to promote a stronger conservation ethic among faith groups.
SPEAKERS - who have submitted profiles; alphabetical by LAST NAME
Karin Allenspach Dr.med.vet, PhD
College of Veterinary Medicine; Iowa State University
Organoids from venom gland of the Western Diamondback- a new tool to study snake envenomation
Matyas Bittenbinder MSc
Department of Chemistry and Pharmaceutical Sciences, Amsterdam Institute of Molecular and Life Sciences (AIMMS)
Development of an in vitro profiling platform for the mechanistic assessment of cytotoxic activities of (Crotalid) snake venoms
As a biologist and toxicologist affiliated with Naturalis and the VU Amsterdam, I study the way in which snake venom affects the human body. Snakebites cause a major health problem on a global scale, claiming more than 100,000 deaths each year. With this research I am part of an international group of scientists that is trying to find a way to reduce the number of deaths from snakebites.
Nicklaus Brandehoff MD
The Aesclepius Snakebite Foundation
Clinical Implications of Venomic Variations in Colorado and Beyond
Dr. Brandehoff is board certified in emergency medicine, medical toxicology, and addiction medicine with a focus on envenomation research. He has an appointment as Assistant Clinical Professor of Emergency Medicine at the University of Colorado School of Medicine and is faculty at the Rocky Mountain Poison and Drug Center. He is also the President and Medical Director for the Asclepius Snakebite Foundation, a 501(c)3 non-profit, that focuses on improving snakebite education and management in West Africa.
Gena Broussard DVM
Consulting Veterinarian – MT Venom LLC
Clinical trial and ELISA efficacy testing results for a novel equine F[AB’]2 antivenom in veterinary medicine
Gena C. Broussard, DVM received her BS degree in Zoology and DVM degree at the University of California at Davis, graduating in 1988. She practiced clinical companion animal medicine for 6 years at a 24-hour, multidoctor practice in Southern California, as well as locum veterinary services at numerous day and emergency practices throughout the region. She and a veterinary classmate established a small animal private practice in Oak Park, California which they successfully managed for 25 years before it was purchased by a veterinary corporation in 2019. Dr. Broussard currently lives in Northern California and is employed as the consultant veterinarian for the MT Venom corporation, as well as volunteering year-round as a mentor in the UC Davis School of Veterinary Medicine Communication and Professional Skills course.
Juan J. Calvete PhD
Evolutionary and Translational Venomics Laboratory, Instituto de Biomedicina de Valencia, CSIC, 46010 Valencia, Spain
The Evils of Quantification in Venomics
Juan J. Calvete (Valencia, 1957) is Professor of the Spanish National Research Council and PI and Director of the Evolutionary and Translational Venomics Laboratory at the Biomedicine Institute of Valencia. Dr. Calvete is an expert in Structural Biology and Biological Mass Spectrometry. His research group has developed proteomic platforms to study the composition and evolution of snake venoms (“venomics”) and the effectiveness of antivenoms (“antivenomics”), with the aim of contributing to alleviate the neglected pathology of snakebite envenoming. Published papers (ORCID 0000-0001-5026-3122) accumulate more than 27000 citations, with an H index of 90 (https://scholar.google.ca/
Fernanda Cardoso PhD
University of Queensland
High-throughput bioassays applied to phylogenetic and envenomation studies of spider and snake venoms
Fernanda Cardoso PhD is a Brazil-born Australian researcher with passion for venoms, pharmacology and therapeutics development. Cardoso was awarded MSc in Molecular Pharmacology and PhD in Immunology and is part of the Institute for Molecular Bioscience at The University of Queensland where she studies venoms from a diverse range of organisms including spider, snake and cone snail. Her strong background in high throughput bioassays, drug discovery and development, and interdisciplinary training in the fields of pharmacology, immunology, and neuroscience provides Dr Cardoso with the skills to identify naturally occurring bioactive molecules, and to study their effects in human physiology with applications in novel therapies for severe envenomation, and to identify novel drug candidates to treat neurologic disorders such as chronic pain and neurodegenerative diseases.
Matthew Cordes PhD
University of Arizona
Recruitment and evolution of brown spider phospholipase D toxin
Matthew Cordes PhD is an Associate Professor of Biochemistry at the University of Arizona. Dr Cordes received his Ph.D in organic chemistry under Dr. Jerome Berson at Yale and followed with a postdoctoral fellowship in structural biology under Dr. Robert Sauer at MIT. Current research interests in the Cordes lab center on protein evolution and include the evolution of de novo protein coding genes, venom toxins, and new protein folds. To probe questions in these areas, the lab utilizes NMR spectroscopy, X-ray crystallography, experimental biochemistry, bioinformatics, and phylogenetics. Contributions of note include the use of transitive homology to track the evolution of new protein folds, the discovery of a compact folded structure in a de novo-evolved yeast protein, and several findings regarding the origin, evolution, chemistry, mechanism, and substrate specificity of dermonecrotic phospholipase D toxins in sicariid spiders.
Jeffrey Ettling PhD
Jacksonville Zoo and Gardens
The Trials and Tribulations of Antivenom Acquisition for Association of Zoos & Aquariums Facilities in the 21st Century.
Jeff Ettling PhD is the President & CEO of the Jacksonville Zoo and Gardens in Jacksonville, Fl. He holds a B.S. and an M.S. in Biology from Southern Illinois University – Edwardsville. He received his Ph.D. in Biology at the University of Missouri – St. Louis. Jeff’s dissertation was based on his work in Armenia where he investigated the spatial ecology, genetic diversity and population structure of the Armenian Viper. Jeff is a native of the St. Louis metro area. His zoo career started 35 years ago. From 1987–1991 he was a reptile keeper and head keeper in the Herpetarium at the Saint Louis Zoo. He moved to the Sedgwick County Zoo in 1991 where he served as curator of herpetology. Jeff returned to the Saint Louis Zoo in 1995 as associate curator of herpetology and aquatics and was promoted to curator in March 1996, a position he held for 21 years. Jeff also served as Director of both the Center for Conservation in Western Asia and the Ron Goellner Center for Hellbender Conservation for the Saint Louis Zoo’s WildCare Institute. In 2017 he returned to the Sedgwick County Zoo as President & CEO, a position he held for five years before moving to the Jacksonville Zoo and Gardens. He is a member of the Association of Zoos & Aquariums (AZA) Field Conservation Committee and serves as a member of AZA accreditation site visit teams. Jeff also served as an adjunct assistant biology professor at the University of Missouri – St. Louis where he taught both undergraduate and graduate courses and served on graduate student committees. In Wichita he taught a herpetology course at Friends University.
Bryan Fry PhD
University of Queensland, Australia
The right tools for the trade: High-throughput methods for venom research
Jacob Galan PhD
Department of Chemistry; Texas A&M University – Kingsville
Snake Venom -Omics: From Biomarker Discovery to Next Generation Therapeutics
Jacob Galan PhD is an Assistant Professor in Biochemistry and Chemistry at the National Natural Toxins Research Center (NNTRC) and Department of Chemistry at Texas A&M University-Kingsville. His research focuses on using the application of high-throughput technologies for the discovery of toxins for potential therapeutic applications and the discovery of novel biologicals and next generation antivenom for the treatment of snakebites. He is particularly interested in understanding snake venom toxicity using novel analytical/omics approaches, snake bite biomarker and structure-guided development of mAb targeting snake venom metalloproteinases. Recently, his work is focused on antivenom/antidote development using the integration of omics, machine-learning computation, and toxin bioengineering.
Charles Gerardo MD, MHS
School of Medicine; Duke University
Using Community Health Centers & Geospatial-AI to Impact Snakebite in the Brazilian Amazon
Charles Gerardo MD is Professor and Chief in the Division of Emergency Medicine; Duke University School of Medicine. Dr. Gerardo graduated with honors from Stanford University with a Bachelors of Science in Biology, and received his MD degree from University of California, Davis. He went on to complete his residency training in Emergency Medicine at Loma Linda University Medical Center. He completed his Masters of Health Sciences from the Duke University Clinical Research and Training Program. In 2000, he joined Emergency Medicine faculty at Duke University and has served in numerous educational, research and administrative leadership roles. His current research focuses on US and global snake envenomation using a variety of methodologies from transitional science and clinical trials to advanced modeling and implementation science. He has published in JAMA, Annals of Emergency Medicine, Academic Emergency Medicine and Clinical Toxicology.
Jacob Glanville PhD
Broad elapid venom protection by broadly neutralizing antibody from a snakebite hyperimmune subject
Jacob Glanville PhD is an serial entrepreneur, and computational immuno-engineer. He built and sold his first company Distributed Bio from founding in March of 2012 to a 104M dollar sale to Charles River Laboratories in December of 2020. During that period, he developed the core business model, the research teams, and the technologies that enabled Distributed Bio to become profitable without investment. As part of the acquisition agreement, he founded Centivax Inc and spun-out his assets in COVID-19 therapeutics, broad-spectrum vaccines, antivenom antibodies, anti-wound pathogen antibodies, anti-CXCR5 autoimmunity therapeutics, and blood-brain barrier translation technologies into Centivax, where he is now CEO. He has developed multiple seminal methods in the fields of high-throughput antibody repertoire sequencing (PNAS 2009), repertoire decoding algorithms (Nature 2017), single-cell TCR receptor & phenotype sequencing (Nature Biotech, 2014), deconstructing genetic variation in the adaptive immune system (Nature Communications 2015, Nature Reports 2016, PNAS 2011, TI 2017), and computationally guided antibody library engineering (JMB 2011, JMB 2013, COSB 2015). He is the inventor of the Centivax Universal Vaccine technology, the SuperHuman discovery library technology, and the Tumbler technology. He is a Stanford University Scientific Advisory Committee member for the Sean Parker Center for Allergy and Asthma Research, a Scientific Advisory Board member for the University of San Francisco’s Biotechnology program, a repeat Gates Foundation/Stanford University Computational and Systems Immunology Grant Recipient while a PhD Candidate with Mark Davis at Stanford, a Recipient of Pfizer Achievement award 2010 while Principal Scientist at Pfizer, and has been a course-founding instructor and guest lecturer for multiple graduate-level applied computational and systems immunology courses at Stanford and USF. Growing up watching his parents grow a successful hotel and restaurant business (La Posada de Santiago) in Guatemala in a Tzutujil village during a civil war, he was happy to find running a biotechnology startup to be similar in many respects, with many of the lessons learned in team management, product refinement, client recruitment and haggling to be surprisingly translatable. From 2012-2019, he nurtured the vision of universal vaccines through the creation of a profitable business to support the work, the building of an animal facility in Guatemala to prove the technology, a collaboration with the University of San Carlos, supported an international research team over 4 years to prove the technology in-vivo, and managed to gather a team of remarkable scientists from USF, Pfizer, Genentech and other places who agreed to join and participate in manifesting the vision.
Spencer Greene MD, MS
HCA Houston Healthcare, Kingwood, TX
The Epidemiology, Clinical Features, and Management of Mojave Rattlesnake Envenomations Reported to the North American Snakebite Registry; and
Seasonal Variation of Agkistrodon Snakebite Severity in Texas
Spencer Greene, MD, MS, FACEP, FACMT, FAACT, FAAEM is the Director of Toxicology and an attending emergency physician at HCA Houston Healthcare-Kingwood. He is a Clinical Professor at the University of Houston College of Medicine. He has directed the Houston Venom Conference since 2013.
Jonas Jurgensen MSc
VenomAid Diagnostics, Denmark
Panelist: Therapeutics & Diagnostics Panel Discussion
Jonas Arnold Jürgensen, M.Sc., Co-founder & CEO of VenomAid Diagnostics. Jonas holds a Master’s in Molecular Biomedicine from University of Copenhagen, with specialization within recombinant antivenom development from the Tropical Pharmacology Lab at the Technical University of Denmark. Combining his scientific insight with his business acumen, he has co-founded VenomAid Diagnostics, a medtech company developing affordable and rapid snakebite diagnostics. He has been recognized with multiple awards, in and outside of academia, most recently being recognized as a Global Shaper by World Economic Forum.
Dan Keyler PharmD
University of Minnessota
Timber Rattlesnake (Crotalus horridus): Biology and Conservation in the Upper Mississippi River Valley .
Glenn King PhD
University of Queensland, Australia
Development of an orally-active spider-venom peptide for treatment of chronic visceral pain
Glenn King PhD completed his PhD at the University of Sydney before postdoctoral studies at the University of Oxford. After academic stints at the University of Sydney and the University of Connecticut Health Center, he joined the Institute for Molecular Bioscience at the University of Queensland in 2007. Glenn is a leader in the field of venoms-based drug and insecticide discovery. His early work on venoms led him to found an agricultural biotechnology company (Vestaron Corporation) that has successfully developed eco-friendly bioinsecticides. Glenn’s current research focuses on the development of drugs to treat nervous system disorders. He recently co-founded Infensa Bioscience, a biotech company that aims to develop venom-derived drugs for treating stroke and myocardial infarction. Glenn’s laboratory maintains one of the largest venom collections in the world, sourced from more than 500 species of invertebrates including ants, assassin bugs, caterpillars, centipedes, scorpions, spiders, and wasps. Glenn has published 3 books, 19 book chapters, and 300 peer-reviewed journal articles
Jeroen Kool PhD
Vrije Universiteit Amsterdam, Netherlands
High Throughput Venomics
Jeroen Kool PhD is an associate professor and a bio-analytical chemist with research interests in high resolution screening of biologically active mixtures. His research achievements allow full compatibility of analytical separations with biological assays (including cellular and zebrafish) and parallel MS detection for investigation of bioactive mixtures (such as natural product extracts, metabolic mixtures, venoms, environmental mixtures) using miniaturized analytical setups and nanospotting technologies. These techniques combining chromatography, mass spectrometry and bioassays in one analytical platform are now known as nanofractionation analytics. He developed hyphenated analytics for both LC and GC separations to bioassays for identification of biologically active toxicants in natural extracts, food and the environment. In case of GC fractionations, he developed, patented and commercialized an automated system for high resolution fractionation of complete GC chromatograms with parallel chemical detection, such as FID and MS. Dr. Kool also developed analytical methodologies for bioactivity profiling of metabolic mixtures from drugs and lead compounds targeting GPCRs, nuclear receptors, protein kinases and ion channels. Other analytics developed by his group allow for bioactivity profiling of biopharmaceutical products (such as monoclonal antibodies) with on-line post-column surface plasmon resonance-based bioassays. Of interest for this conference: his group worked on post-column microfluidics and nanospotting analytics for analysis of bioactive mixtures only available in low amounts. Insect and animal venoms are examples that contain many different, highly potent, and sometimes very selective peptide ligands for a large variety of medicinal targets. Recent years, he also started developing and applying analytics for characterization of venom induced pathologies in order to better understand snakebite envenoming and as such develop better treatment strategies based on antivenom & small molecular drugs. His most recent research efforts focus on two venom analytics research lines: 1) HTS venomics, which is able to rapidly and automatically (both the measurements and the data processing) characterize large numbers of venoms in terms of venom composition (which will be presented during this conference). 2) Venom metabolomics and venom toxin quantification studies which allows opening up large population studies on venom variation. This research is based on LC-MS analysis of many different venoms (interspecies and/or intraspecies) with script-based automated relative quantification of the toxins in each venom, retrieved from the LC-MS data. This analytical approach uses the HTS venomics data in parallel in order to bridge correlating toxin masses from LC-MS with toxin identities. Our most recent results show that measuring dozens of venoms in several days followed by fully automated script-based data processing yielded relative toxin abundances in each venom ready to be analyzed further by for example PCA analysis
Matthew Lewin MD, PhD
Update on sPLA2 inhibition for the treatment of snakebite envenoming
Matthew Lewin MD, PhD holds a PhD degree in the field of neurophysiology and is Board Certified in the field of Emergency Medicine. He is a Fellow of the California Academy of Sciences as well as the American College of Emergency Physicians. He recently served on the World Health Organization Snakebite Envenoming Working Group that produced a roadmap for the purpose of reducing death and disability from snakebite envenoming 50% by the year 2030. He earned his BSc in entomology from the University of California, Berkeley and MD and PhD at the University of Texas MD Anderson Cancer Center Graduate School of Biomedical Sciences where he was the 2020 Distinguished Alum. He is Director of the California Academy of Sciences Center for Exploration and Travel Health and is founder of the Public Benefit Company, Ophirex, Inc. developing lifesaving antidotes for neglected tropical diseases such as snakebite envenoming. The observation that many patients present to emergency care settings for injuries, signs or symptoms that are later attributed to Parkinson’s Disease mandates efforts to understand opportunities for early identification. He was the recipient of the 2017 UCSF John L. Ziegler Outstanding Mentorship in Global Health Sciences Award that is the origin of the project funded herein.
Ray Norton PhD
Monash University, Australia
Venom-derived inhibitors of microglial Kv1.3 potassium channels as therapeutic leads for autoimmune and neuroinflammatory diseases
Ray Norton PhD: Professor Ray Norton holds a personal chair at the Monash Institute of Pharmaceutical Sciences, Melbourne, Australia. He obtained his PhD in chemistry from the Australian National University and undertook postdoctoral studies in the US before returning to Australia as a QEII Fellow at the Roche Research Institute of Marine Pharmacology in Sydney. His lab at Monash employs a range of biophysical approaches, including NMR, SPR, ITC and X-ray crystallography, as well as molecular modelling and design, in studies of peptides and proteins from venomous organisms. One of the venom-derived peptides he works with has completed Phase 1 clinical trial for autoimmune diseases and another is the basis for development of ultra-rapid acting insulins that are currently undergoing preclinical evaluation. He is also designing small cyclic peptides that show promise as anti-infective agents with a novel mechanism of action. Ray Norton has published over 400 articles, received numerous national awards, and is an inventor on more than 10 patents. His h-factor is 72 and his papers have been cited > 20,050 times (Google Scholar). He is Chair of the Council of the International Conference on Magnetic Resonance in Biological Systems (ICMRBS) and a member of the Council of the International Society on Toxinology. He is Co-Editor-in-Chief of Toxicon and Toxicon: X, and an elected Fellow of the International Society of Magnetic Resonance.
Michelle Ruha MD, FACMT
University of Arizona; Banner Hospital
The North American Snakebite Registry
Anne-Michelle Ruha, MD is a Professor of Internal Medicine and Emergency Medicine at the University of Arizona College of Medicine – Phoenix. Her clinical practice is in medical toxicology at Banner – University Medical Center Phoenix (BUMCP) and Phoenix Children’s Hospital, where she cares for patients with various envenomations and toxic exposures. Her primary research focus is on rattlesnake envenomation. She is the Principal Investigator of the American College of Medical Toxicology’s (ACMT) Toxicology Investigator Consortium’s North American Snakebite Registry. She has published over 30 studies and case reviews in the peer-reviewed medical literature on the topic of envenomations as well as medical textbook chapters on snake, scorpion, and spider envenomations. She is also active in medical toxicology education, teaching fellows, residents and students about envenomations and poisonings.
Emelyn Salazar PhD
Texas A&M University – Kingsville
Evaluation of the modulatory effect of north american viper venoms on the innate immune response using an experimental model of monocyte-derived macrophages
Claire Sharp BVMS, MS
Murdoch University, Australia
Elapid envenomation in dogs and cats – The Australian experience
Claire Sharp BVMS, MS, DACVECC graduated veterinary school in Australia in 2002, before undertaking an internship and residency in emergency and critical care at the University of Missouri, where she was exposed to viper envenomated dogs and cats. Claire was then on Faculty at Tufts University for 6 years before returning to Australia in 2015. Claire has been very involved in the Australian veterinary SnakeMap initiative, a multi-institutional registry of envenomated dogs and cats in Australia, and conducts clinical research in the field of snake envenomation.
POSTER PRESENTERS - who have submitted photos
Timothy Beck MD
School of Medicine, Duke University
MAPPING RESOURCES FOR SNAKEBITES AND OTHER ANIMAL ENVENOMING CLINICAL MANAGEMENT IN THE BRAZILIAN AMAZON
Carmen Cayo MS
Texas A&M University-Kingsville
ANALYSIS OF THE NEUROTOXIC EFFECTS OF Naja kaouthia (MONOCLED COBRA) SNAKE VENOM USING MUSCLE AND GLIA CELL LINES
Aaron Gomez MSc
Instituto Clodomiro Picado
INTRAGENERIC CROSS-REACTIVITY BETWEEN MONOSPECIFIC RABBIT SERA AGAINST VENOMS OF THE MEDICALLY MOST IMPORTANT BITIS SPP. AND ECHIS SPP. AFRICAN SNAKES