Scielo RSS <![CDATA[Journal of Venomous Animals and Toxins including Tropical Diseases]]> vol. 20 num. lang. en <![CDATA[SciELO Logo]]> <![CDATA[Current challenges for confronting the public health problem of snakebite envenoming in Central America]]> Snakebite envenoming is a serious public health problem in Central America, where approximately 5,500 cases occur every year. Panama has the highest incidence and El Salvador the lowest. The majority, and most severe, cases are inflicted by the pit viper Bothrops asper (family Viperidae), locally known as ‘terciopelo’, ‘barba amarilla’ or ‘equis’. About 1% of the bites are caused by coral snakes of the genus Micrurus (family Elapidae). Despite significant and successful efforts in Central America regarding snakebite envenomings in the areas of research, antivenom manufacture and quality control, training of health professionals in the diagnosis and clinical management of bites, and prevention of snakebites, much remains to be done in order to further reduce the impact of this medical condition. This essay presents seven challenges for improving the confrontation of snakebite envenoming in Central America. Overcoming these challenges demands a coordinated partnership of highly diverse stakeholders though inter-sectorial and inter-programmatic interventions. <![CDATA[A historical approach to scorpion studies with special reference to the 20 <sup>th</sup> and 21st centuries]]> This work provides historical context about scorpion studies from the end of the 19 th century to the present day. The content is mainly addressed to non-zoologists, working in research fields that embrace scorpion biology, notably to those working with venoms and toxins. The historical aspects described include academic professional scholars who worked on scorpion classification and general distribution patterns; and to a lesser extent, on studies of ecology and natural history. The aim is not to provide an exhaustive description of all scholars who in one way or another became involved with scorpions, but rather of those who greatly contributed during a given period to the research of these organisms. No critical analysis of the work of previous researchers is undertaken, but some comments are proposed to bring clarification on ‘who’s who’. Since a global consensus in relation to classification and/or distribution patterns has not been reached among modern experts, these different approaches are also presented without judgment. Consequently, distinct approaches remain open for discussion. <![CDATA[Purification and characterization of a hyaluronidase from venom of the spider <em>Vitalius dubius </em> (Araneae, Theraphosidae)]]> Background Venom hyaluronidase (Hyase) contributes to the diffusion of venom from the inoculation site. In this work, we purified and characterized Hyase from the venom of Vitalius dubius (Araneae, Theraphosidae), a large theraphosid found in southeastern Brazil. Venom obtained by electrical stimulation of adult male and female V. dubius was initially fractionated by gel filtration on a Superdex® 75 column. Active fractions were pooled and applied to a heparin-sepharose affinity column. The proteins were eluted with a linear NaCl gradient. Results Active fractions were pooled and assessed for purity by SDS-PAGE and RP-HPLC. The physicochemical tests included optimum pH, heat stability, presence of isoforms, neutralization by flavonoids and assessment of commercial antivenoms. Hyase was purified and presented a specific activity of 148 turbidity-reducing units (TRU)/mg (venom: 36 TRU/mg; purification factor of ~4). Hyase displayed a molecular mass of 43 kDa by SDS-PAGE. Zymography in hyaluronic-acid-containing gels indicated an absence of enzyme isoforms. The optimum pH was 4-5, with highest activity at 37°C. Hyase was stable up to 60°C; but its activity was lost at higher temperatures and maintained after several freeze-thaw cycles. The NaCl concentration (up to 1 M) did not influence activity. Hyase had greater action towards hyaluronic acid compared to chondroitin sulfate, and was completely neutralized by polyvalent antiarachnid sera, but not by caterpillar, scorpion or snakes antivenoms. Conclusion The neutralization by arachnid but not scorpion antivenom indicates that this enzyme shares antigenic epitopes with similar enzymes in other spider venoms. The biochemical properties of this Hyase are comparable to others described. <![CDATA[Identification of two novel cytolysins from the hydrozoan <em>Olindias sambaquiensis</em> (Cnidaria)]]> Background : Although the hydrozoan Olindias sambaquiensis is the most common jellyfish associated with human envenomation in southeastern and southern Brazil, information about the composition of its venom is rare. Thus, the present study aimed to analyze pharmacological aspects of O. sambaquiensis venom as well as clinical manifestations observed in affected patients. Crude protein extracts were prepared from the tentacles of animals; peptides and proteins were sequenced and submitted to circular dichroism spectroscopy. Creatine kinase, cytotoxicity and hemolytic activity were evaluated by specific methods. Results : We identified two novel cytolysins denominated oshem 1 and oshem 2 from the tentacles of this jellyfish. The cytolysins presented the amino acid sequences NEGKAKCGNTAGSKLTFKSADECTKTGQK (oshem 1) and NNSKAKCGDLAGWSKLTFKSADECTKTGQKS (oshem 2) with respective molecular masses of 3.013 kDa and 3.375 kDa. Circular dichroism revealed that oshem 1 has random coils and small α-helix conformation as main secondary structure whereas oshem 2 presents mainly random coils as its main secondary structure probably due to the presence of W (13) in oshem 2. The hemolysis levels induced by oshem 1 and oshem 2 using a peptide concentration of 0.2 mg/mL were, respectively, 51.7 ± 6.5% and 32.9 ± 8.7% (n = 12 and p ≤ 0.05). Oshem 1 and oshem 2 showed significant myonecrotic activity, evaluated by respective CK level measurements of 1890.4 ± 89 and 1212.5 ± 103 (n = 4 and p ≤ 0.05). In addition, myonecrosis was also evaluated by cell survival, which was measured at 72.4 ± 8.6% and 83.5 ± 6.7% (n = 12 and p ≤ 0.05), respectively. The structural analysis showed that both oshem 1 and oshem 2 should be classified as a small basic hemolytic peptide. Conclusion : The amino acid sequences of two peptides were highly similar while the primary amino acid sequence analysis revealed W (22th) as the most important mutation. Finally oshem 1 and oshem 2 are the first cytolytic peptides isolated from the Olindias sambaquiensis and should probably represent a novel class of cytolytic peptides. <![CDATA[Comparative analysis of the venom proteome of four important Malaysian snake species]]> Background Naja kaouthia, Ophiophagus hannah, Bungarus fasciatus and Calloselasma rhodostoma are four venomous snakes indigenous to Malaysia. In the present study, their proteomic profile by two-dimensional gel electrophoresis (2-DE) have been separated and compared. Results The 2-DE of venoms of the four species snake demonstrated complexity and obvious interspecies differences in proteome profiles. A total of 63 proteins were identified in the four species: C. rhodostoma - 26, N. kaouthia - 16, O. hannah - 15 and B. fasciatus - 6. Conclusions Despite the identifications of major proteins in the four snake species, a large number of protein spots from the 2-DE were unidentified even though the spots displayed high-quality MALDI-TOF-MS spectra. Those identified included phospholipase A2 proteins in all four venoms, long neurotoxins in both cobra species and the C. rhodostoma venom found with the most varied types of peptidases, i.e. metalloproteinase kistomin, halystase and L-amino acid oxidase. <![CDATA[Association among <em>H. pylori </em> virulence markers <em>dupA, cagA</em> and <em>vacA</em> in Brazilian patients]]> Background: Only a few Helicobacter pylori-infected individuals develop severe gastric diseases and virulence factors of H. pylori appear to be involved in such clinical outcomes. Duodenal ulcer promoting gene A (dupA) is a novel virulence factor of Helicobacter pylori that is associated with duodenal ulcer development and reduced risk for gastric carcinoma in some populations. The aims of the present study were to determine the presence of dupA gene and evaluate the association among dupA and other virulence factors including cagA and vacA in Brazilian patients. Gastric biopsies were obtained from 205 dyspeptic patients (100 children and 105 adults). DNA was extracted and analyzed for the presence of H. pylori and its virulence factors using the polymerase chain reaction method. Results: Patients with gastritis tested positive for H. pylori more frequently. The dupA gene was detected in 41.5% of them (85/205); cagA gene was found in 98 isolates (47.8%) and vacA genotype s1/m1 in 50.2%, s1/m2 in 8.3%, s2/m2 in 36.6%, s2/m1 in 0.5% and s1/s2/m1/m2 in 4.4%. We also verified a significant association between cagA and dupA genes [p = 0.0003, relative risk (RR) 1.73 and confidence interval [CI] = 1.3-2.3]. The genotypes s1/m1 were also associated with dupA gene (p = 0.0001, RR: 1.72 and CI: 1.3-2.2). The same associations were found when analyzing pediatric and adult groups of patients individually. Conclusion: Ours results suggest that dupA is highly frequent in Brazilian patients and is associated with cagA gene and vacA s1/m1 genotype, and it may be considered an important virulence factor in the development of gastric diseases in adults or children. <![CDATA[Clinical aspects of envenomation caused by <em>Tityus obscurus </em> (Gervais, 1843) in two distinct regions of Pará state, Brazilian Amazon basin: a prospective case series]]> Background : Scorpion envenomations are a major public health problem in Brazil, whose most dangerous cases are attributable to the genus Tityus. This study was designed to compare the clinical and demographic features of envenomations by 77tyus obscurus in two areas of the state of Pará located in the Amazon basin. Were compared demographic findings, local and systemic signs and symptoms of human envenomations caused by T. obscurus that occurred in western and eastern areas of the state. Results : Forty-eight patients with confirmed envenomation by T. obscurus were evaluated from January 2008 to July 2011. Most of them came from the eastern region, where male and female patients were present in similar numbers, while males predominated in the west. Median age groups were also similar in both areas. Most scorpion stings took place during the day and occurred significantly more frequently on the upper limbs. The time between the sting and admission to the health center was less than three hours in both areas. Most eastern patients had local manifestations while in the west, systemic manifestations predominated. Local symptoms were similar in both areas, but systemic signs and symptoms were more common in the west. Symptoms frequently observed at the sting site were local and radiating pain, paresthesia, edema, erythema, sweating, piloerection and burning. The systemic manifestations were significantly higher in patients from the west. Futhermore, neurological symptoms such as general paresthesia, ataxia, dysarthria, myoclonus, dysmetria, and electric shock-like sensations throughout the body were reported only by patients from the west. Conclusion : The present study shows that two regions of Para state differ in the clinical manifestations and severity of confirmed envenomation by T. obscurus which suggests a toxicity variation resulting from the diversity of T. obscurus venom in different areas of the Brazilian Amazon basin, and that T. serrulatus antivenom can be successfully used against T. obscurus. <![CDATA[Mild reproductive effects of the <em>Tityus bahiensis </em> scorpion venom in rats]]> Background Scorpion envenoming is a public health problem in Brazil, where Tityus serrulatus and T. bahiensis are considered the most dangerous scorpions. They are well adapted to urbanized environments, and there is an increasing probability of human exposure to these venoms, including during pregnancy. Not much is known about the effects of prenatal exposure to the venom, and no information is available to aid in the rational treatment of victims stung during pregnancy. Thus, this study aimed to investigate whether venom from the scorpion T. bahiensis administered once to pregnant female rats at a dose that causes a moderate envenomation may lead to deleterious effects on the reproductive performance of the dams and on the development of their offspring. This is the first work demonstrating that T. bahiensis venom, when administered experimentally to rats, alters maternal reproductive performance and the morphological development of fetuses. The venom was given to dams on the 5th (GD5) or on the 10th (GD10) gestational day. After laparotomy, on GD21, fetuses and placentas were counted, weighed and externally analyzed. The corpora lutea were counted. The sex and vitality of fetuses were evaluated, and each litter was then randomly divided for visceral or skeletal analyses. Data were analyzed by ANOVA followed by the Tukey-Kramer test and Fisher's exact test. The significance level for all tests was set at p &lt; 0.05. Results : GD5 group presented an increased number of pre-implantation losses. Weight gains in fetuses and placentas were observed in the GD5 and GD10 groups. Weights of the heart and lungs were elevated in GD5 and GD10 and liver weight in GD10. Conclusions : Moderate envenomation by T. bahiensis scorpion venom alters maternal reproductive performance and fetal development. However, these are preliminary results whose causes should be investigated more carefully in future studies. <![CDATA[Evaluation of canine and feline leishmaniasis by the association of blood culture, immunofluorescent antibody test and polymerase chain reaction]]> Background : This study aimed to evaluate the occurrence of Leishmania spp. in dogs and cats from Botucatu, São Paulo state, and Campo Grande, Mato Grosso do Sul state, Brazil, by the association of three diagnostic tests: blood culture in liver infusion tryptose medium, immunofluorescent antibody test and polymerase chain reaction. Fifty blood samples of dogs and cats from the Center for Zoonosis Control in Campo Grande, an area endemic for canine visceral leishmaniasis, were collected randomly, as well as canine and feline blood samples from the Municipal Kennel and Animal Protection Association in Botucatu, currently considered a transmission-free, non-endemic area. Results : Of the 50 dog blood cultures from Botucatu, three (6%) were positive and of the 50 cats, two (4%) were positive. In Campo Grande, 29 dog blood cultures (58%) were positive and all (100%) cats negative by this test. Polymerase chain reaction detected Leishmania spp. in 100% of dog and cat samples from Botucatu but found all the cats from Campo Grande to be negative. On the other hand, 36 dogs from Campo Grande were positive (72%) by the same technique. Immunofluorescent antibody test in Botucatu found 100% of dogs and cats non-reactive, while in Campo Grande, it detected positivity in 32 dogs (64%) and 15 cats (30%). Conclusions : The results show the importance of not only continuous epidemiological surveillance in areas not endemic for leishmaniasis, but also research for accurate diagnosis of this zoonosis. <![CDATA[A case of stings in humans caused by <em>Sclerodermus </em> sp. in Italy]]> In the last years, stings of Sclerodermus species in humans have been sporadically reported in Italy. In order to draw attention to these bethylid wasps of medical importance, we report the case of documented Sclerodermus sp. stings on the dorsum, abdomen, arms, and thighs of a 40-year-old man and his wife. The sting sites developed raised red itchy rash. The source of environmental contamination was identified in a worm-eaten sofa purchased from a used furniture dealer and placed in the living room about a month and half earlier. The lesions on the man and his wife rapidly healed within 3 to 4 days once they left the house and treatment for the lesions was instituted. Physicians, dermatologists, medical and public health entomologists, as well as specific categories of workers should be aware of the risk of exposure to Sclerodermus stings. <![CDATA[Seroprevalence of flaviviruses antibodies in water buffaloes <em>(Bubalus bubalis) </em>in Brazilian Amazon]]> Background The state of Pará encompasses 26% of Brazilian Amazon where an enormous diversity of arboviruses has been found. This study aimed to assess the prevalence and distribution of hemagglutination-inhibition antibodies against antigens of six Flavivirus (yellow fever virus, Ilheus virus, Saint Louis encephalitis virus, Cacipacore virus, Bussuquara virus and Rocio virus) in water buffaloes in Pará state, Brazil. The prevalence of antibodies in these farm animals is important to determine the circulating arboviruses. Findings All investigated arboviruses were detected in the species studied and our results indicate that water buffaloes are susceptible to Flavivirus infection. Furthermore, there is solid evidence of active circulation of these viruses in the Brazilian Amazon. Conclusions Water buffaloes showed higher prevalence of heterotypic antibody reactions and we hypothesized that they can serve as sentinels to detect the movement of such arboviruses in the Brazilian Amazon.