Abstract in English:Clostridium is an anaerobic bacterial genus. The clostridia produce more protein toxins than any other bacterial genus and are a rich reservoir of toxins for research and medicinal uses. Clostridia are widely spread in the environment: soil, dust and water, presenting more than 120 described species, although few can cause diseases. Diseases can grossly be divided into neurotropic disorders (nervous system is primarily affected), enterotoxemias (affecting intestinal tract and parenchymatous organs), and gas gangrene (myonecrosis with toxemia). Undoubtedly the most widely recognized infection due to anaerobes was clostridial myonecrosis, but recently interest has arisen for the role of clostridia in intestinal diseases. This report describes the most important species, the diseases caused by them, and their occurrence in Brazil, focusing on cattle raising.
Abstract in English:Botulinum toxin is the most potent toxin known. It is readily absorbed from mucosal surfaces. If dispersed as an aerosol or mixed in the food or water it can lead to a large outbreak of botulism. The disease presents as a symmetric descending paralysis in an afebrile patient. Cranial nerve involvement with diplopia, dysarthria, dysphonia, dysphagia and respiratory paralysis is seen after a variable incubation period. The treatment is mainly supportive. The source of the toxin is Clostridium botulinum, an anaerobic gram-positive spore-forming organism. Some other species of Clostridium like C. butyricum and C. baratii also produce the toxin. The toxin is heat labile and can be inactivated by heating at 100°C for 10 minutes. The toxin acts at the peripheral cholinergic nerve terminals at the neuromuscular junctions, postganglionic parasympathetic ganglia, etc, and affects neurotransmitter release by inhibiting exocytosis. Clinical uses in various medical fields were found for it.
Abstract in English:Injuries caused by venomous snakes are considered a problem of public health in Brazil, and further studies for a better knowledge are very important. The aim of this work is to describe clinical and epidemiological characteristics that were observed from 1995 to 2000 in the Hospital for Tropical Diseases of Araguaína, Tocantins State, Brazil, which is a unit of health that takes care of patients suffering from tropical diseases. We studied 440 individuals and the most common characteristics observed were masculine sex, age among 15-45 years, bite in low members, and injuries caused by snakes of the Bothrops genus. The signs and symptoms more frequently observed were edema, pain, erythema, and bleeding. The most observed systemic manifestation was alteration of blood coagulation. The most frequent complications were abscess, necrosis, bacterial infection, and renal failure. The mortality rate was 3%. These data are very important for the evaluation of the problem.
Abstract in English:The aim of this study was to evaluate the effect of snake venom derived fibrin glue on the healing of the deep digital flexor tendon, during three periods. The tendon of the 2nd digit of 30 thoracic limbs of dogs was partially sectioned for glue application. Biopsies were performed 7, 15, and 30 days post surgery for the clinical and morphological study of tendons. Analysis of the results showed that 73.3% of the tendons showed stump retraction and 16.6% moderate to excessive adherence, which affected sliding. There was a significant difference in the number of inflammatory cells among the three studied periods, being the highest on day 15. The morphological analysis revealed a typical tendon healing process with a lower level of inflammation in the acute phase, facilitating the cicatricial maturation phase. Snake venom derived fibrin glue promotes the healing in dog flexor tendon.
Abstract in English:ELISA was used to evaluate, accompany, and compare the humoral immune response of Swiss mice during hyperimmunization with native and Cobalt-60-irradiated (60Co) venoms of Bothrops jararaca, Bothrops jararacussu and Bothrops moojeni. Potency and neutralization were evaluated by in vitro challenges. After hyperimmunization, immunity was observed by in vivo challenge, and the side effects were assessed. The animals immunization with one LD50 of each venom occurred on days 1, 15, 21, 30, and 45, when blood samples were collected; challenges happened on the 60th day. Results showed that ELISA was efficient in evaluating, accompanying and comparing mouse immune response during hyperimmunization. Serum titers produced with natural venom were similar to those produced with irradiated venom. Immunogenic capacity was maintained after 60Co-irradiation. The sera produced with native venom showed neutralizing potency and capacity similar to those of the sera produced with irradiated venom. All antibodies were able to neutralize five LD50 from these venoms. Clinical alterations were minimum during hyperimmunization with irradiated venom, however, necrosis and death occurred in animals inoculated with native venom.
Abstract in English:Numerous plants are used as snakebite antidotes in Brazilian folk medicine, including Casearia sylvestris Swartz, popularly known as guaçatonga. In this study, we examined the action of a hydroalcoholic extract from C. sylvestris on the neuromuscular blockade caused by bothropstoxin-I (BthTX-I), a myotoxin from Bothrops jararacussu venom, in mouse isolated phrenic nerve-diaphragm (PND) preparations. Aqueous (8 and 12 mg/ml, n=4 and 5, respectively) and hydroalcoholic (12 mg/ml, n=12) extracts of the leaves of C. sylvestris caused facilitation in PND preparations followed by partial neuromuscular blockade. BthTX-I (20 µg/ml, n=4) caused 50% paralysis after 65±15 min (mean ± S.E.M). Preincubation (30 min at 37° C) of BthTX-I (20 µg/ml, n=4) with a concentration of the hydroalcoholic extract (4 mg/ml) that had no neuromuscular activity, such as the control (n=5), prevented the neuromuscular blockade caused by the toxin. This protection may be mediated by compounds such as flavonoids and phenols identified by thin-layer chromatography and colorimetric assays.
Abstract in English:The epidemiology and clinical findings of scorpion stings in Sanliurfa region of Turkey, from May to September 2003, were evaluated in this study. Mesobuthus eupeus (M. eupeus) plays a role on 25.8% of the scorpionism cases. This study also showed that intoxications caused by M. eupeus in the southeast of Anatolia region were seen in hot months of the summer, especially on July. Females and people above 15 years old were mostly affected and stung on extremities. Intense pain in the affected area was observed in 98.7% cases, hyperemia in 88.8%, swelling in 54.6%, burning in 19.7%, while numbness and itching were seen less frequently. In our study, the six most frequently observed symptoms were local pain, hyperemia, swelling, burning, dry mouth, thirst, sweating, and hypotension. In this study involving 152 M. eupeus toxicity cases, patients showed local and systemic clinical effects but no death was seen. Autonomic system and local effects characterized by severe pain, hyperemia and edema were dominantly seen in toxicity cases.
Abstract in English:Among domestic animals, dogs are considered to be the major reservoirs of trypanosomatids and, due to their proximity to man, the presence of these parasites in dogs is an alert to actions aiming at triatomine control. Fifty dogs (26 males and 24 females), aged from 2 months to 15 years, belonging to 30 chronic Chagas’ disease individuals from 15 different municipalities in the western region of São Paulo State, Brazil, were subjected to blood collection for the following tests: artificial xenodiagnosis, blood culture, and Polymerase Chain Reaction (PCR). Forty-three (86%) out of 50 dogs were positive to at least one of the tests performed; 34 (68%) were positive to xenodiagnosis, 30 (60%) to blood culture, and 25 (50%) to PCR for T. cruzi and/or T. rangeli. Although triatomines were not detected during the intra and peridomiciliary inspections in the dog owners’ residences, the results obtained demonstrate that there is a transmission cycle whereby triatomine vector may be participating in the infection epidemiological chain.
Abstract in English:The aim of this study was to evaluate the morphology of the species Sticholecitha serpentis Prudhoe, 1949 by means of histological procedures. Helminths were previously fixed in Railliet & Henry solution, uncompressed and were included in 2-hydroxyethyl-methacrylate. Longitudinal and transverse serial sections with a 4-mum thickness were performed in a microtome (Leica RM 2165), stained with haematoxylin-eosin and then analyzed in a computerized image analysis system (Qwin Lite 2.5, Leica). Structures of systematic value, such as oral sucker, acetabulum, prepharynx, pharynx, esophagus, intestinal caeca, vitelline glands, ovary, uterus, cirrus pouch and testicles were described. Structures that were poorly visible in total preparations were also observed and described, such as efferent ducts, ejaculatory duct, prostate, seminal vesicle, seminal receptacle, Laurer’s channel, Mehlis’ gland, vitelline ducts, metraterm, genital atrium, digestive glands and excretory vesicle. We demonstrated that histological analysis can supply important data regarding the morphological characterization of S. serpentis and will be able to contribute to systematic studies of trematodes.
Abstract in English:In human and canine renal histological studies of visceral leishmaniasis (VL), the etiological agent is rarely found in situ. The objective of this study was to evaluate PCR in identifying the etiological agent in spleen, liver, lymph node, and kidneys of VL-seropositive dogs. Twenty-five symptomatic (case group) and 15 asymptomatic (control group) VL-seropositive dogs of different breeds, sexes, and ages from Teresina, Piauí State, Brazil, were used. Serologic diagnosis was made by enzyme-linked immunosorbent assay and indirect immunofluorescence test. Animals were subjected to euthanasia and necropsy. Renal fragments were immersed in buffered formaldehyde solution. Spleen, liver, lymph node, and kidney samples were collected and frozen at -70ºC until DNA extraction. After dehydration and diaphanization, renal fragments were infiltrated and embedded in paraffin, cut at 3 µm, and stained with hematoxylin-eosin (HE). DNA amplification used an automatic thermocycler with specific Leishmania primers. All case-group dogs and 2 controls showed positive results in spleen, liver, or lymph node PCRs. There was a significant difference by Fisher exact test. In symptomatic seropositive dogs, renal histopathological evaluation showed one animal (4%) with amastigote forms of Leishmania in inflammatory infiltrate, and kidney PCRs detected Leishmania DNA in eight animals (32%). The conclusion was that PCR is more precise than the conventional histopathology in detecting the Leishmania parasite in kidney.
Abstract in English:Acute infection by Toxoplasma gondii leads to suppression of cell-mediated immunity, facilitating chronic infection. One of the causes of immunosuppression is Interleukin-10 (IL-10) production. Glucan is used to stimulate phagocytosis. Our objective was to study IL-10 induction in male BALB/c mice with acute T. gondii BTU-2 strain infection, glucan immunostimulation, and sulfadiazine treatment. Animals were distributed into 7 groups: G1: infected with T. gondii; G2: infected with T. gondii and treated with sulfadiazine; G3: infected with T. gondii and immunostimulated with glucan; G4: infected with T. gondii, immunostimulated with glucan, and treated with sulfadiazine; G5: imunostimulated with glucan; G6: treated with saline; and G7: treated with sulfadiazine. IL-10 levels were determined by ELISA; the highest levels were found in G2, G3 and G4, and the lowest in G1 (p<0.001). Groups G1 to G5 and G7 had substantially higher levels than G6 (p<0.001). In this study, the highest IL-10 levels were found in groups treated with glucan.
Abstract in English:Snake venom (sv) C-type lectins encompass a group of hemorrhagic toxins, which are able to interfere with hemostasis. They share significant similarity in their primary structures with C-type lectins of other animals, and also present a conserved carbohydrate recognition domain (CRD). A very well studied sv C-type lectin is the heterodimeric toxin, convulxin (CVX), from the venoms of South American rattlesnakes, Crotalus durissus terrificus and C. d. cascavella. It consists of two subunits, alfa (CVXalpha , 13.9 kDa) and beta (CVXbeta , 12.6 kDa), joined by inter and intra-chain disulfide bounds, and is arranged in a tetrameric alpha4beta4 conformation. Convulxin is able to activate platelet and induce their aggregation by acting via p62/GPVI collagen receptor. Several cDNA precursors, homolog of CVX subunits, were cloned by PCR homology screening. As determined by computational analysis, one of them, named crotacetin beta subunit, was predicted as a polypeptide with a tridimensional conformation very similar to other subunits of convulxin-like snake toxins. Crotacetin was purified from C. durissus venoms by gel permeation and reverse phase high performance liquid chromatography. The heterodimeric crotacetin is expressed in the venoms of several C. durissus subspecies, but it is prevalent in the venom of C. durissus cascavella. As inferred from homology modeling, crotacetin induces platelet aggregation but noticeably exhibits antimicrobial activity against Gram-positive and Gram-negative bacteria.
Abstract in English:Visceral leishmaniasis (VL) is a zoonosis that affects both animals and man. Dogs are the etiological agent’s main reservoir. The aim of this study was to evaluate the clinical laboratory aspects and renal histopathology of VL dogs. Thirty-four symptomatic (case) and 17 asymptomatic (control) VL seropositive dogs of different breeds, sexes, and ages from Teresina, Piauí State, Brazil, were used. Diagnosis was confirmed by enzyme-linked immunosorbent assay and indirect immunofluorescence test. Clinical and laboratory tests included blood cell count and renal function analysis (urea and creatinine). Animals were subjected to euthanasia and necropsy. Renal fragments were prepared by the usual histological techniques and stained with hematoxylin-eosin and periodic acid-Schiff. Physical examination showed that lymph node hypertrophy (85.29%) and skin lesions (35.29%) were frequent in the case group. Anemia was found in 55.88% of the case and in 11.76% of the control group. There was a significant difference between groups by Fisher’s exact test. Two case-group dogs showed azotemia. Renal histopathological evaluation showed that 61.76% case and 17.65% control-group dogs had membranoproliferative glomerulonephritis. Mesangial proliferative glomerulonephritis was seen in 32.35% case and 64.70% control-group animals. There was a significant difference for both types of glomerulonephritis between groups. Amastigote forms of Leishmania were found in the renal parenchyma, in the inflammatory infiltrate of one case-group dog. We concluded that, in canine VL, regardless of the clinical signs at physical examination, the kidneys are frequently compromised.
Abstract in English:Scorpionism is a public health problem in some places in Mexico. The clinical symptoms of envenomation by scorpion sting are by sympathetic and parasympathetic stimulation, developing systemic and local symptoms. The Central Nervous System (CNS) is one of the organs that are affected. In some cases, cerebral edema develops. In this report we present two pediatric cases with the association of envenomation by scorpion sting and cerebral edema. The first case developed severe cerebral edema, which progressed to a fatal outcome; and the other case developed mild cerebral edema with a satisfactory evolution. The pathophysiology of this complication is not well known and probably is the consequence of hypoxia, secondary to respiratory failure, laryngospasm and seizures that are manifestations of envenomation by scorpion sting.
Abstract in English:A survey was carried out in a hospital of Nova Iguaçu, Rio de Janeiro, Brazil, in the period from July 1999 to March 2002, to determine the infection rate of Listeriamonocytogenes in HIV+ patients with diarrhea symptoms; 134 samples were processed by microbiological methods. The results demonstrated 12.68% of positive samples. However, no statistical differences were observed for age or sex in the studied group, suggesting that this microorganism should be regarded in the differential diagnosis of infectious processes in HIV+ patients in the area.
Abstract in English:Laboratory animals are fundamental to study immunological aspects and the efficacy of new drugs to treat leishmaniasis. However, we do not have practical and good animal models to study leishmaniasis caused by Leishmania (Viannia) braziliensis - L(V)b. In this study, thirty-two experimental animals (Cavia porcellus) were injected in the hind foot with 3x10(5) promastigote forms of L(V)b. The animals were followed for eight weeks. None of the experimental animals developed lesions or presented the parasite in any of the tests performed (histopathological exam, smears, culture, inoculation in hamsters, and polymerase chain reaction).