Correction: A hidden deadly venomous insect: First eco-epidemiological assessment and risk mapping of lonomism in Argentina.

[This corrects the article DOI: 10.1371/journal.pntd.0009542.].

Epidemiological characterization of lonomism in South America.

Lonomism is the envenomation caused by accidental contact with Lonomia caterpillars, and this is a public health priority in South America since it is relatively common but remains underestimated. This study presents an updated and integrative analysis of reliable global data from 1960 to 2020 on the epidemiology of this envenomation in the whole continent. A total of 13,186 notifications were recorded for South America: 13,056 (99.01%) in Brazil, 49 (0.37%) in Argentina, 43 (0.33%) in Colombia, 29 (0.22%) in Venezuela, 6 (0.05%) in Peru and 3 (0.02%) in French Guiana. The number of new locations reporting accidents has increased since the first formally notifications at the middle of the last century. Most of these locations are situated in Brazil, the pioneer in deeply researching the Lonomia genus and its impacts in public health. Most victims were males, in the economically productive age group, and accidental contact occurred more frequently in the upper limbs while doing activities outdoors in urban/rural areas. Regarding the determinants of clinical outcome, countries where patients received delayed medical care were associated with a higher number of moderate and/or severe cases, as well as a higher chance of progressing to death. Additionally, the longer the delay for accessing medical care, the higher the risk of developing systemic complications, thereby increasing the need for specific treatment. Our study also shows that accidents globally occurred more frequently in the summer months and in the beginning of autumn. Although having identified several shortcomings in the documents selected and verified that notifications are strongly biased by public policies adopted by each South American country, this study provides the first comprehensive assessment of lonomism in South America, demonstrating the increase in the number of accidents, and their expansion to other areas of the continent over time. Our findings will undoubtedly help guide the appropriate allocation of resources and implementation of prevention strategies and define priority criteria for epidemiological surveillance of this neglected tropical disease.

Shedding Light on the Dentition and Venom Delivery System of the Rear-Fanged Snake, Galvarinus chilensis chilensis (Serpentes: Dipsadidae: Tachymenini) from Chile.

Although the rear-fanged snake Galvarinus chilensis chilensis (formerly named Tachymenis ch. chilensis) causes ophidian accidents with clinical importance in Chile, the anatomical and histological characterizations of the venom delivery system (venom gland and fang) of this species still remain unknown. This study describes the dentition and characteristics of fangs and their ontogenetic variations in G. ch. chilensis. Moreover, histological and histochemistry analyses of the venom glands of this species are presented. Using micro-computed tomography and scanning electron microscopy, the dentitions of neonates, juveniles, and adults were analyzed, and no ontogenetic variations in teeth length and number present in the dentary and maxilla were observed. Moreover, we found three types of basic teeth, with distributional patterns conserved in all ontogenetic categories. The fangs exhibited a groove from the base to the middle. At the end of the groove, prominent ridges are formed. The fang and groove lengths were significantly distinct between ontogenetic categories. No differences between females and males were observed. Histologically, we found that the venom gland is close to the fangs and has a seromucous composition. Our results describe, for the first time, the distributional pattern and characteristics of the dentition and venom delivery system of the poorly studied snake G. ch. chilensis.

[Resistance to antibiotics of clinical relevance in a hospital of Corrientes city]. / Resistencia a antibióticos de relevancia clínica en un hospital de Corrientes.

Carbapenemaseproducing bacteria are involved in infections and colonizations and associated with high morbidity and mortality. Their identification facilitates the design and implementation of interventions aimed at reducing the risk of infections and deaths. The objective of this study was to determine the prevalence of carbapenemase-producing microorganisms in the main public hospital in the city of Corrientes, Argentina, and to determine their susceptibility to antibiotics commonly used in clinical practice. We analyzed 674 clinical samples from the same number of adults admitted to different inpatient units of the Hospital Escuela Gral. José Francisco de San Martín during the period September-December 2018. The bacterial identification was carried out through manual biochemical tests and the susceptibility to antimicrobials was evaluated according to the recommendations of the Clinical and Laboratory Standards Institute. We identified 115 carbapenemase-producing bacteria of the following types: KPC (90, 78%), OXA-ACI (24, 21%) and OXA-163 (≈1%). Among the microorganisms involved in infections (n = 56; 49%), most of those of the KPC type (n = 32; 57%) showed sensitivity only against amikacin (27/32; 84%), while most of those of the OXA-ACI type ( 24; 43%) showed significant sensitivity only against minocycline (17/24; 71%) and colistin (n = 19/24; 79%). This study demonstrated the presence of carbapenemase-producing microorganisms in all the investigated hospital units and a high frequency of resistance to antimicrobials commonly used in clinical practice. This information is relevant to adapt the therapeutic schemes and hygienic-sanitary measures to the local reality.

Las bacterias productoras de carbapenemasas están involucradas en infecciones y colonizaciones y se asocian a elevada morbimortalidad. Su identificación facilita el diseño y la implementación de intervenciones dirigidas a reducir el riesgo de infecciones y óbitos. El objetivo de este estudio fue determinar la prevalencia de microorganismos productores de carbapenemasas en el principal hospital público de la ciudad de Corrientes, Argentina, y determinar sus perfiles de susceptibilidad a antibióticos comúnmente usados en la práctica clínica. Fueron incluidos 674 muestras clínicas provenientes del mismo número de adultos de las diferentes unidades de internación del Hospital Escuela Gral. José Francisco de San Martín durante el período septiembre-diciembre 2018. La identificación de las bacterias se realizó mediante pruebas bioquímicas manuales y la susceptibilidad a los antimicrobianos se evaluó según las recomendaciones del Clinical and Laboratory Standars Institute. Fueron identificadas 115 bacterias productoras de carbapenemasas de tipo KPC (90, 78%), OXA­ACI (24, 21%) y OXA-163 (≈1%). De los 56 (49%) microorganismos involucrados en infecciones, la mayoría de las del tipo KPC (n=32; 57%) mostró sensibilidad solo a amikacina (27/32; 84%), mientras que la mayoría de las del tipo OXA­ACI (n=24; 43%) solo frente a minociclina (17/24; 71%) y colistina (19/24; 79%). En todas las unidades de hospitalización investigadas se comprobó la presencia de microorganismos productores de carbapenemasas y alta frecuencia de resistencia a antimicrobianos de uso habitual en la práctica clínica. Esta información es relevante para adecuar los esquemas terapéuticos y las medidas higiénico-sanitarias a la realidad local.

Resistencia a antibióticos de relevancia clínica en un hospital de Corrientes / Resistance to antibiotics of clinical relevance in a hospital of Corrientes city

Resumen Las bacterias productoras de carbapenemasas están involucradas en infecciones y colonizaciones y se asocian a elevada morbimortalidad. Su identificación facilita el diseño y la implementación de intervenciones dirigidas a reducir el riesgo de infecciones y óbitos. El objetivo de este estudio fue determinar la prevalencia de microorganismos productores de carbapenemasas en el principal hospital público de la ciudad de Corrientes, Argentina, y determinar sus perfiles de susceptibilidad a antibióticos comúnmente usados en la práctica clínica. Fueron incluidos 674 muestras clínicas provenientes del mismo número de adultos de las diferentes unidades de internación del Hospital Escuela Gral. José Francisco de San Martín durante el período septiembre-diciembre 2018. La identificación de las bacterias se realizó mediante pruebas bioquímicas manua les y la susceptibilidad a los antimicrobianos se evaluó según las recomendaciones del Clinical and Laboratory Standars Institute. Fueron identificadas 115 bacterias productoras de carbapenemasas de tipo KPC (90, 78%), OXA-ACI (24, 21%) y OXA-163 (~1%). De los 56 (49%) microorganismos involucrados en infecciones, la mayoría de las del tipo KPC (n=32; 57%) mostró sensibilidad solo a amikacina (27/32; 84%), mientras que la mayoría de las del tipo OXA-ACI (n=24; 43%) solo frente a minociclina (17/24; 71%) y colistina (19/24; 79%). En todas las unidades de hospitalización investigadas se comprobó la presencia de microorganismos productores de carbapenemasas y alta frecuencia de resistencia a antimicrobianos de uso habitual en la práctica clínica. Esta información es relevante para adecuar los esquemas terapéuticos y las medidas higiénico-sanitarias a la realidad local.

Abstract Carbapenemase-producing bacteria are involved in infections and colonizations and associated with high morbidity and mortality. Their identification facilitates the design and implementation of interventions aimed at reducing the risk of infections and deaths. The objective of this study was to determine the prevalence of carbapenemase-producing microorganisms in the main public hospital in the city of Corrientes, Argentina, and to determine their susceptibil ity to antibiotics commonly used in clinical practice. We analyzed 674 clinical samples from the same number of adults admitted to different inpatient units of the Hospital Escuela Gral. José Francisco de San Martín during the period September-December 2018. The bacterial identification was carried out through manual biochemical tests and the susceptibility to antimicrobials was evaluated according to the recommendations of the Clinical and Laboratory Standards Institute. We identified 115 carbapenemase-producing bacteria of the following types: KPC (90, 78%), OXA-ACI (24, 21%) and OXA-163 (~1%). Among the microorganisms involved in infections (n = 56; 49%), most of those of the KPC type (n = 32; 57%) showed sensitivity only against amikacin (27/32; 84%), while most of those of the OXA-ACI type ( 24; 43%) showed significant sensitivity only against minocycline (17/24; 71%) and colistin (n = 19/24; 79%). This study demonstrated the presence of carbapenemase-producing microorgan isms in all the investigated hospital units and a high frequency of resistance to antimicrobials commonly used in clinical practice. This information is relevant to adapt the therapeutic schemes and hygienic-sanitary measures to the local reality.

Pharmaceutical biotechnological potential of filamentous fungi isolated from textile industry.

The need for more effective drugs for the treatment of infectious diseases as well as for general applications including wound healing and burn surgery, has guided efforts for the discovery of new compounds of medical interest. Microorganisms found in textile industrial waste have the ability to produce a variety of enzymes and/or secondary metabolites including molecules of pharmaceutical interest. The present work investigated the biotechnological potential of filamentous fungi isolated from textile industry wastewater for the production of collagenase and antimicrobial metabolites. From 28 isolates assayed, Sarocladium sp. ITF33 showed specific collagenolytic activity with values of 7.62 and 9.04 U mg-1 for the intracellular and extracellular fractions, respectively. The isolate Penicillium sp. ITF28 showed the best antimicrobial activity, reaching MIC ranging from 1.0 to 0.0625 mg mL-1 against five pathogenic bacteria. Molecular analyzes suggest that the isolate Sarocladium sp. ITF 33 can be considered a species not yet described. The results of the present work encourage studies of characterization and purification of the enzymes and secondary metabolites produced by the isolates found aiming future applications in the medical and pharmaceutical fields.

Lonomia envenomation in Brazil: an epidemiological overview for the period 2007-2018.

BACKGROUND: Among the Lepidoptera with medical importance in Brazil, larvae of Lonomia moth (Saturniidae: Hemileucinae) stand out by being the etiological agent of the lonomism, a form of erucism in which the most troubling symptoms include systemic hemorrhage that can lead to death. METHODS: This study provides an epidemiological overview of accident notifications with Lonomia registered by the Brazilian Reportable Disease Information System (SINAN) between 2007 and 2018. The categories of sociodemographic aspects of the victim, accident characteristics, and clinical data (6,636 records) were analysed by the chi-square test for goodness of fit (α=0.05). By the same test, accident frequencies by month, year, and state were also compared. To explore the spatial distribution of notifications and to identify significant space-time and purely spatial clusters, a spatial scan statistic (SaTScan) was used. RESULTS: The epidemiological profile of most of the victims had at least one of the following characteristics: male, >50 y of age, ethnically classified as white, and with a low level of education. Accidents in urban areas were as frequent as in rural areas. A higher frequency of non-work-related accidents was detected. Victims were mostly stung on the upper limbs. Most victims received medical care within the first 3 h after the accident. Most cases were classified as mild, although 12 deaths were reported. The south states of Brazil concentrate the highest frequencies of notifications. Summer was the season with the greatest number of cases, and the majority of the notifications occurred between 2017 and 2018. CONCLUSION: These results provide an overall and current situation assessment of the lonomism in Brazil, and they should enable health authorities to improve the management of this envenomation in states/regions that share the high epidemiological risk of exposure to Lonomia.

Potential distribution and ecological conditions of Lonomia obliqua Walker 1855 (Saturniidae: Hemileucinae) in Brazil.

Lonomia obliqua Walker 1855 (Lepidoptera: Saturniidae) is a species of moth which larvae are responsible for the lonomism, a form of envenomation that has been occurring in Brazil since the 1980s. Despite the importance in public health, the geographical distribution and their ecological aspects are unknown. Therefore, in the present study, we present a potential geographical distribution map for L. obliqua in Brazil, based on the combination of different Ecology Niche Modelling (ENM) algorithms. A total of 38 occurrence points were distributed in the southern/ southeastern regions of Brazil and in the province of Misiones (Argentina), which were divided for calibration and evaluation of the model. Eight continuous climatic and soil variables were selected from 16 previously calculated for model calibration. The final model-map is composed of a combination of four algorithms (Gower, Mahalanobis, MAXENT and SVM), with samples of pseudo-absences outside a Bioclimatic Envelope (BIOCLIM) in quantity equal to the presences. This model-map was binarized from the Low Presence Threshold (LPT) and cut only to the Brazilian area. According to this map, the areas predicted as suitable for L. obliqua are restricted between latitudes ˜12° and ˜32°, and longitudes ˜39° and ˜57°, with extension of 1,181,604 km². The model-map was also validated with external data from samples of the species, at municipality level, in the state of Rio Grande do Sul (Brazil). From this information, we extracted the values of variables related to climate and soil, and with additional variables related to the land use and type of vegetation, in order to contribute to the ecological knowledge of the species. In general, the map and the ecological information obtained can serve as a tool for public health agents in Brazil to adequately guide preventive strategies and attention to lonomism in the country, and with addendum on habitat loss and accident conditions with the species.

Understanding toxicological implications of accidents with caterpillars Megalopyge lanata and Podalia orsilochus (Lepidoptera: Megalopygidae)

Megalopygids Megalopyge lanata and Podalia orsilochus are common causative agents of accidents in agricultural workers. These accidents are provoked by dermal contact at their larval stage and are characterized by cutaneous reactions, such as burning pain, edema and erythema, typically mild and self-limited. There is very little information about their venoms and their toxicological implications on human health. Thus, we employed proteomic techniques and biological assays to characterize venoms (bristle extracts) from caterpillars of both species collected from Misiones, Argentina. The electrophoretic profiles of both venoms were substantially different, and they presented proteins related to toxicity, such as serinepeptidases, serpins and lectins. P. orsilochus venom exhibited higher caseinolytic activity than M. lanata venom, agreeing with the fact that only P. orsilochus venom hydrolyzed human fibrin(ogen). In addition, the latter shortened the clotting time triggered by calcium. While the venom of M. lanata induced a mild inflammatory lesion in mouse skin, P. orsilochus venom caused prominent necrosis, inflammatory infiltration and hemorrhage at the site of venom injection. On the other hand, P. orsilochus venom was better recognized by Lonomia obliqua antivenom, although many of its proteins could not be cross-reacted, what may explain the difference in the clinical manifestations between accidents by Podalia and those by Lonomia. Altogether, this study provides relevant information about the pathophysiological mechanisms whereby both caterpillars can induce toxicity on human beings, and paves the way for novel discovery of naturally occurring bioactive compounds.

Understanding toxicological implications of accidents with caterpillars Megalopyge lanata and Podalia orsilochus (Lepidoptera: Megalopygidae)

Megalopygids Megalopyge lanata and Podalia orsilochus are common causative agents of accidents in agricultural workers. These accidents are provoked by dermal contact at their larval stage and are characterized by cutaneous reactions, such as burning pain, edema and erythema, typically mild and self-limited. There is very little information about their venoms and their toxicological implications on human health. Thus, we employed proteomic techniques and biological assays to characterize venoms (bristle extracts) from caterpillars of both species collected from Misiones, Argentina. The electrophoretic profiles of both venoms were substantially different, and they presented proteins related to toxicity, such as serinepeptidases, serpins and lectins. P. orsilochus venom exhibited higher caseinolytic activity than M. lanata venom, agreeing with the fact that only P. orsilochus venom hydrolyzed human fibrin(ogen). In addition, the latter shortened the clotting time triggered by calcium. While the venom of M. lanata induced a mild inflammatory lesion in mouse skin, P. orsilochus venom caused prominent necrosis, inflammatory infiltration and hemorrhage at the site of venom injection. On the other hand, P. orsilochus venom was better recognized by Lonomia obliqua antivenom, although many of its proteins could not be cross-reacted, what may explain the difference in the clinical manifestations between accidents by Podalia and those by Lonomia. Altogether, this study provides relevant information about the pathophysiological mechanisms whereby both caterpillars can induce toxicity on human beings, and paves the way for novel discovery of naturally occurring bioactive compounds.

Stinging caterpillars from the genera Podalia, Leucanella and Lonomia in Misiones, Argentina: A preliminary comparative approach to understand their toxicity.

Dermal contact with Lepidoptera specimens at their larval stage (caterpillar) may cause systemic and/or local envenomation. There are multiple venomous species of them in Argentina, but their overall venom composition is poorly known. Lately, several cases of envenomation have been reported in the Misiones province, Northeastern Argentina. Thus, this work aimed to compare the protein composition, and the enzymatic properties of bristle extracts from caterpillars belonging to the families Megalopygidae (Podalia ca. fuscescens) and Saturniidae (Leucanella memusae and Lonomia obliqua) - the most common causative agents of accidents in Misiones -, and additionally to test their cross-reactivity with the L. obliqua antivenom produced in Brazil. Saturniidae venoms exhibited striking similarity in both their electrophoretic protein profile, and antigenic cross-reactivity. All venoms degraded azocasein - with the highest proteolytic activity observed in the P. ca. fuscescens bristle extract -, and hyaluronic acid, but the latter at low levels. Lonomia obliqua venom exhibited the highest level of phospholipase A2 activity. Bristle extracts from P. ca. fuscescens and L. obliqua both degraded human fibrin(ogen) and shortened the clotting time triggered by calcium, while L. memusae venom inhibited plasma coagulation. Proteins related to the coagulation disturbance were identified by mass spectrometry in all samples. Altogether, our findings show for the first time a comparative biotoxinological analysis of three genera of caterpillars with medical relevance. Moreover, this study provides relevant information about the pathophysiological mechanisms whereby these caterpillar bristle extracts can induce toxicity on human beings, and gives insight into future directions for research on them.

Patagonfibrase modifies protein expression of tissue factor and protein disulfide isomerase in rat skin.

Patagonfibrase is a hemorrhagic metalloproteinase isolated from the venom of the South American rear-fanged snake Philodryas patagoniensis, and is an important contributor to local lesions inflicted by this species. The tissue factor (TF)-factor VIIa complex, besides triggering the coagulation cascade, has been demonstrated to be involved in inflammatory events. Our aim was to determine whether patagonfibrase affects the expression of TF and protein disulfide isomerase (PDI), an enzyme that controls TF biological activity, at the site of patagonfibrase injection, and thus if they may play a role in hemostatic and inflammatory events induced by snake venoms. Patagonfibrase (60 µg/kg) was administered s.c. to rats, and after 3 h blood was collected to evaluate hemostasis parameters, and skin fragments close to the site of injection were taken to assess TF and PDI expression. Patagonfibrase did not alter blood cell counts, plasma fibrinogen levels, or levels of TF activity in plasma. However, by semiquantitative Western blotting, patagonfibrase increased TF expression by 2-fold, and decreased PDI expression by 3-fold in skin samples. In agreement, by immunohistochemical analyses, prominent TF expression was observed in the subcutaneous tissue. Thus, patagonfibrase affects the local expression of TF and PDI without inducing any systemic hemostatic disturbance, although that they may be involved in the local inflammatory events induced by hemorrhagic metalloproteinases. Once antivenom therapy is not totally effective to treat the local injury induced by snake venoms, modulation of the activity and expression of TF and/or PDI might become a strategy for treating snake envenomation.

Inflammatory effects of patagonfibrase, a metalloproteinase from Philodryas patagoniensis (Patagonia Green Racer; Dipsadidae) venom.

Patagonfibrase is a P-III class metalloproteinase isolated from the venom of Philodryas patagoniensis, a South-American, rear-fanged 'colubrid' snake responsible for accidents with clinical significance. Since local inflammatory reactions are conspicuous signs of snakebites inflicted by this species and taking into consideration that most snake venom metalloproteinases exhibit inflammatory activity, this study deals with the proinflammatory effects evoked by patagonfibrase. Herein, we demonstrate that patagonfibrase causes a time- and dose-dependent hemorrhagic edema when injected into mouse hind paws. The peak of edema occurred at 30 min after injection, and the minimum edematogenic dose was 0.021 µg. By histological analysis, the presence of moderate to marked edema and hemorrhage, and a mild inflammatory infiltrate was observed. When injected subcutaneously into the scrotal bag of mice, patagonfibrase induced cell recruitment with a significant alteration in physiological parameters of leukocyte-endothelium interaction. The presence of 1 mmol/L o-phenanthroline, which chelates metal ions, significantly inhibited the proinflammatory effects induced by patagonfibrase. Taken together, these results imply that patagonfibrase is an important contributor to local inflammation elicited by P. patagoniensis envenomation, which may pave the way for novel therapeutic strategies to treat this snakebite. Moreover, our findings demonstrate for the first time that a venom metalloproteinase from a rear-fanged snake elicits proinflammatory effects mainly mediated by its catalytic activity.

Inflammatory effects of patagonfibrase, a metalloproteinase from Philodryas patagoniensis (Patagonia Green Racer; Dipsadidae) venom

Patagonfibrase is a P-III class metalloproteinase isolated from the venom of Philodryas patagoniensis, a South-American, rear-fanged 'colubrid' snake responsible for accidents with clinical significance. Since local inflammatory reactions are conspicuous signs of snakebites inflicted by this species and taking into consideration that most snake venom metalloproteinases exhibit inflammatory activity, this study deals with the proinflammatory effects evoked by patagonfibrase. Herein, we demonstrate that patagonfibrase causes a time- and dose-dependent hemorrhagic edema when injected into mouse hind paws. The peak of edema occurred at 30 min after injection, and the minimum edematogenic dose was 0.021 ìg. By histological analysis, the presence of moderate to marked edema and hemorrhage, and a mild inflammatory infiltrate was observed. When injected subcutaneously into the scrotal bag of mice, patagonfibrase induced cell recruitment with a significant alteration in physiological parameters of leukocyte-endothelium interaction. The presence of 1 mmol/L o-phenanthroline, which chelates metal ions, significantly inhibited the proinflammatory effects induced by patagonfibrase. Taken together, these results imply that patagonfibrase is an important contributor to local inflammation elicited by P. patagoniensis envenomation, which may pave the way for novel therapeutic strategies to treat this snakebite. Moreover, our findings demonstrate for the first time that a venom metalloproteinase from a rear-fanged snake elicits proinflammatory effects mainly mediated by its catalytic activity.

Systemic pathological alterations caused by Philodryas patagoniensis colubrid snake venom in rats.

Very little is known about the systemic effects caused by Philodryas patagoniensis colubrid snake venom. In this work, this venom was tested for its ability to induce histopathological changes in rats after its intramuscular, subcutaneous or intravenous administration, by light microscopic examination of some organs (cerebellum, cerebrum, lung, liver, kidney and heart). Four rats were used for each dose of 0.23, 0.45 and 0.90 mg of venom in 0.3 ml of phosphate-buffered saline solution (pH 7.4). Aliquots of blood were withdrawn at different time intervals for enzymatic determination of alanine aminotransferase, aspartate aminotransferase and creatine kinase levels. After 2h the animals were killed by an overdose of anesthetic, and samples of kidney, heart, liver, lung, cerebrum and cerebellum were taken to microscopic examination (hematoxylin and eosin stain). Histologically, no abnormality was observed in heart tissue, in none of the administration routes of the venom used. However, histological observations showed multifocal hemorrhage in cerebellum, cerebrum and lung sections, severe peritubular capillary congestion in kidney sections and hydropic degeneration in liver sections, when venom was administrated intravenously. The subcutaneous route showed similar results to the previous one, with the exception of cerebellar hemorrhage. Intramuscularly, neither cerebral nor cerebellar hemorrhage was observed. Plasma alanine aminotransferase and aspartate aminotransferase increased levels were demonstrated, mainly when venom was administered intravenously or subcutaneously. Our results suggest that P. patagoniensis venom induces moderate histopathological changes in vital organs of rats. These changes are initiated at early stages of the envenomation and may be associated with a behavioral or functional abnormality of those organs during envenoming.

Edematogenic and myotoxic activities of the Duvernoy's gland secretion of Philodryas olfersii from the north-east region of Argentina.

Philodryas olfersii is found in South America, from Amazonas to Patagonia. It is important to characterize the venom of P. olfersii, who inhabits the North-East region of Argentina, since snake venoms are known to exhibit considerable variability in composition and biological activities. In this work, mice weighing 18-20 g (n = 4 for each experimental group) were used. For the edematogenic activity mice were injected s.c. in the right foot pad with 50 microl of solutions containing different amounts of venom, whereas the left foot pad was injected with 50 microl of PBS. Two hours after injection mice were killed by cervical dislocation and both feet were cut off and weighed individually. For the myotoxic activity mice were injected i.m. with 100 microl of solutions containing 40 microg of venom. Blood samples were extracted after 1, 3, 6, 8, 10, 12, 14, 16 and 24 h of venom injection to determinate serum CPK activity and mice were sacrificed at the same time intervals to obtain the inoculated gastrocnemius muscle. They were fixed with Bouin solution and stained with Hematoxylin-Eosin. Results showed that P. olfersii venom exhibits a high edematogenic activity (MED = 0.31 microg) and a moderate myotoxic activity. Myonecrosis reached its highest level after 12 h of venom injection as shown by plasmatic CPK levels (5,401 +/- 330 IU/l) and microscopic assay. It demonstrates the potential toxicity of the venom of P. olfersii, who inhabits the North-East region of Argentina. It also reinforces the original warning concerning the potential danger of bites by colubrids.

Edematogenic and myotoxic activities of the Duvernoys gland secretion of Philodryas olfersii from the north-east region of Argentina.

Philodryas olfersii is found in South America, from Amazonas to Patagonia. It is important to characterize the venom of P. olfersii, who inhabits the North-East region of Argentina, since snake venoms are known to exhibit considerable variability in composition and biological activities. In this work, mice weighing 18-20 g (n = 4 for each experimental group) were used. For the edematogenic activity mice were injected s.c. in the right foot pad with 50 microl of solutions containing different amounts of venom, whereas the left foot pad was injected with 50 microl of PBS. Two hours after injection mice were killed by cervical dislocation and both feet were cut off and weighed individually. For the myotoxic activity mice were injected i.m. with 100 microl of solutions containing 40 microg of venom. Blood samples were extracted after 1, 3, 6, 8, 10, 12, 14, 16 and 24 h of venom injection to determinate serum CPK activity and mice were sacrificed at the same time intervals to obtain the inoculated gastrocnemius muscle. They were fixed with Bouin solution and stained with Hematoxylin-Eosin. Results showed that P. olfersii venom exhibits a high edematogenic activity (MED = 0.31 microg) and a moderate myotoxic activity. Myonecrosis reached its highest level after 12 h of venom injection as shown by plasmatic CPK levels (5,401 +/- 330 IU/l) and microscopic assay. It demonstrates the potential toxicity of the venom of P. olfersii, who inhabits the North-East region of Argentina. It also reinforces the original warning concerning the potential danger of bites by colubrids.