Micro-computed tomographic assessment of dentinal microcrack formation in straight and curved root canals in extracted teeth prepared with hand, rotary and reciprocating instruments.

AIM: To compare microcrack formation in roots of extracted teeth after the shaping of straight and curved root canals with hand, rotary and reciprocating files using micro-computed tomographic (micro-CT) analysis. METHODOLOGY: Thirty straight mandibular incisors and 30 severely curved mesial roots of mandibular molars were randomly divided into 6 experimental groups (n = 10) according to the systems used for the root canal preparation and the root canal curvature: ProTaper Universal for Hand Use (Dentsply Sirona, Ballaigues, Switzerland), HyFlex EDM (Coltene-Whaledent, Altstätten, Switzerland) and Reciproc Blue (VDW, Munich, Germany) files used in mandibular incisors (straight canals) and mesial roots of mandibular molars (curved canals). The roots were imaged with micro-CT scanning at an isotropic resolution of 14 µm before and after root canal preparation, and the cross-sectional images generated were assessed to detect microcracks. RESULTS: All dentinal defects identified after root canal preparation were already present before instrumentation, and no new microcracks were detected. Dentinal microcracks were present in 19% (ProTaper Universal for Hand Use), 11% (Hyflex EDM) and 23% (Reciproc Blue) of the cross-sections when the instrumentation was performed in mandibular incisors. Instrumentation of mandibular molars revealed microcracks in 15% (ProTaper Universal for Hand Use), 16% (Hyflex EDM) and 17% (Reciproc Blue) of the cross-sections. CONCLUSIONS: Preparation of straight and curved root canals with ProTaper Universal for Hand Use, HyFlex EDM and Reciproc Blue systems did not produce microcracks in extracted teeth when evaluated with micro-CT.

Primary gastric rupture in 20 horses from Midwestern Brazil: case report / Ruptura gástrica primária em 20 equinos no Centro-Oeste do Brasil: relato de caso

An 11-year (2007-2018) survey of epidemiological, clinical and pathological findings of horses with primary gastric rupture (PGR) was conducted. Twenty horses presented PGR, nine (45%) horses were clinically evaluated, eleven (55%) were sent dead, and all animals were necropsied. PGR contributed to a prevalence of 0.31% (9/2,868) of all equid attendances, 1.83% (9/491) of colic cases, and 4.1% (20/487) of all equid necropsies. Highly fermentable feed (n=7), gastric impaction (n=4), and perforating gastric ulcer (n=1) were the main causes of PGR; whilst eight horses presented idiopathic gastric rupture. Clinically evaluated horses were tachycardic, tachypneic, febrile, dehydrated, with increased abdominal tension, abnormal mucous membranes and reduced to absent intestinal borborygmi. Improper dietary management, such as the ingestion of low-quality roughage and highly fermentable feedstuffs were detected as the main factors associated with PGR in Midwestern Brazil. It is important to raise awareness in horse owners about proper feed management to minimize PGR.(AU)

Foi realizado um levantamento de 11 anos (2007-2018) dos achados epidemiológicos, clínicos e patológicos de equinos com ruptura gástrica primária (RGP). Vinte equinos apresentaram RGP, dos quais nove (45%) foram avaliados clinicamente e 11 (55%) foram enviados mortos, sendo todos os animais necropsiados. A RGP contribuiu com prevalência de 0,31% de todos os atendimentos de equídeos (9/2.868), 1,83% (9/491) dos casos de cólica, e 4,1% (20/487) das necropsias em equídeos. Alimentos altamente fermentáveis (n=7), compactação gástrica (n=4) e perfuração de úlcera gástrica (n=1) foram as principais causas de RGP, enquanto oito equinos tiveram ruptura gástrica idiopática. Os equinos avaliados clinicamente apresentaram-se taquicárdicos, taquipneicos, febris, desidratados, com mucosas anormais, aumento da tensão abdominal e motilidade intestinal reduzida. O manejo inadequado da dieta, como a ingestão de forragens de baixa qualidade e alimentos altamente fermentáveis, foi o principal fator de risco associado à RGP no Centro-Oeste do Brasil. É importante aumentar a conscientização dos proprietários de equinos sobre o manejo alimentar adequado para minimizar a RGP.(AU)

Primary gastric rupture in 20 horses from Midwestern Brazil: case report / Ruptura gástrica primária em 20 equinos no Centro-Oeste do Brasil: relato de caso

An 11-year (2007-2018) survey of epidemiological, clinical and pathological findings of horses with primary gastric rupture (PGR) was conducted. Twenty horses presented PGR, nine (45%) horses were clinically evaluated, eleven (55%) were sent dead, and all animals were necropsied. PGR contributed to a prevalence of 0.31% (9/2,868) of all equid attendances, 1.83% (9/491) of colic cases, and 4.1% (20/487) of all equid necropsies. Highly fermentable feed (n=7), gastric impaction (n=4), and perforating gastric ulcer (n=1) were the main causes of PGR; whilst eight horses presented idiopathic gastric rupture. Clinically evaluated horses were tachycardic, tachypneic, febrile, dehydrated, with increased abdominal tension, abnormal mucous membranes and reduced to absent intestinal borborygmi. Improper dietary management, such as the ingestion of low-quality roughage and highly fermentable feedstuffs were detected as the main factors associated with PGR in Midwestern Brazil. It is important to raise awareness in horse owners about proper feed management to minimize PGR.(AU)

Foi realizado um levantamento de 11 anos (2007-2018) dos achados epidemiológicos, clínicos e patológicos de equinos com ruptura gástrica primária (RGP). Vinte equinos apresentaram RGP, dos quais nove (45%) foram avaliados clinicamente e 11 (55%) foram enviados mortos, sendo todos os animais necropsiados. A RGP contribuiu com prevalência de 0,31% de todos os atendimentos de equídeos (9/2.868), 1,83% (9/491) dos casos de cólica, e 4,1% (20/487) das necropsias em equídeos. Alimentos altamente fermentáveis (n=7), compactação gástrica (n=4) e perfuração de úlcera gástrica (n=1) foram as principais causas de RGP, enquanto oito equinos tiveram ruptura gástrica idiopática. Os equinos avaliados clinicamente apresentaram-se taquicárdicos, taquipneicos, febris, desidratados, com mucosas anormais, aumento da tensão abdominal e motilidade intestinal reduzida. O manejo inadequado da dieta, como a ingestão de forragens de baixa qualidade e alimentos altamente fermentáveis, foi o principal fator de risco associado à RGP no Centro-Oeste do Brasil. É importante aumentar a conscientização dos proprietários de equinos sobre o manejo alimentar adequado para minimizar a RGP.(AU)

HLA-G 14-bp Ins/Ins Genotype in Patients Harbouring Helicobacter pylori Infection: A Potential Risk Factor?

H. pylori is a potent pathogen due to its capacity to successfully evade host defence mechanisms. Despite inducing immune responses in infected individuals, sometimes these responses fail to clear the infection and the bacterium establishes a persistent infection leading to chronic inflammation. In this context, we hypothesized that human leucocyte antigen G (HLA-G), a non-classical major histocompatibility complex molecule that has the ability to regulate immune responses both in physiological and in pathological conditions, may play an important role in promoting tolerance and helping H. pylori to subvert host defence and consequently establish a chronic infection. Therefore, we evaluated the expression of HLA-G 14-bp Ins/Del polymorphism in patients harbouring H. pylori infection, as well as their relationship with histological and demographic variables, to gain a better understanding of the actual role of HLA-G and its genetic polymorphisms in bacterial infection. Sixty-eight patients with clinical symptoms suggestive of H. pylori infection were enrolled to assess HLA-G 14-bp Ins/Del polymorphism allele and genotype frequencies. After adjustment for covariates (age and gender), the odds of having the genotype Ins/Ins, compared to Del/Del, were 3.77 times greater among HP+ cases than among controls. These findings suggest that the 14-bp Ins/Ins genotype, already associated with inflammatory and autoimmune diseases as well as some viral and parasitic infections, could confer a greater risk of developing H. pylori infection.

Impairment of Interleukin-17A Expression in Canine Visceral Leishmaniosis is Correlated with Reduced Interferon-γ and Inducible Nitric Oxide Synthase Expression.

Dogs are the primary urban reservoir of Leishmania infantum and play a crucial role in the transmission of this parasite to man via sandflies. The spleen and liver are the main target organs of L. infantum infection, but few studies have evaluated the immune response to this infection in the canine liver. To identify the immunological mediators involved in resistance and/or susceptibility to canine visceral leishmaniosis (CVL), we selected 21 dogs naturally infected by L. infantum and classified as asymptomatic or symptomatic. Immunological parameters were analysed and correlations with clinical signs were determined. Symptomatic dogs showed higher numbers of parasites and less leucocyte infiltration in the liver compared with asymptomatic dogs. The progression of this disease was characterized not only by the down regulation of T helper (Th) 1-related cytokines, such as interferon (IFN)-γ and tumour necrosis factor (TNF)-α, but also by the down regulation of genes encoding interleukin (IL)-17A, inducible nitric oxide synthase (iNOS) and IL-10 in the spleen and liver in symptomatic dogs compared with asymptomatic dogs. Importantly, IL-17A gene transcription level was positively correlated with mRNA expression for iNOS and IFN-γ. Th1- and Th17-related cytokines therefore appear to play a role in restricting parasite growth via iNOS activation and decrease susceptibility of dogs to CVL.

Effect of burst TENS and conventional TENS combined with cryotherapy on pressure pain threshold: randomised, controlled, clinical trial.

OBJECTIVE: To assess the immediate effect of conventional and burst transcutaneous electrical nerve stimulation (TENS) in combination with cryotherapy on pain threshold and tolerance in healthy individuals. DESIGN: Randomised, controlled trial. SETTING: University laboratory. PARTICIPANTS: One hundred and twelve healthy women. INTERVENTIONS: Volunteers were allocated at random to seven groups (n=16): (1) control, (2) placebo TENS, (3) conventional TENS, (4) burst TENS, (5) cryotherapy, (6) cryotherapy in combination with burst TENS, and (7) cryotherapy in combination with conventional TENS. Pain threshold and tolerance were measured by applying a pressure algometer at the lateral epicondyle of the humerus, before and after each intervention. MAIN OUTCOME MEASURES: The primary outcome measure was pressure pain threshold. RESULTS: A significant increase in pain threshold and tolerance at the 5% level of significance was recorded as follows: burst TENS {pain threshold: mean difference 1.3 [95% confidence interval (CI) 1.4 to 1.2]; pain tolerance: mean difference 3.8 (95% CI 3.9 to 3.7)}, cryotherapy [pain threshold: mean difference 1.3 (95% CI 1.4 to 1.2); pain tolerance: mean difference 1.9 (95% CI 1.8 to 2.0)] and cryotherapy in combination with burst TENS [pain threshold: mean difference 2.6 (95% CI 2.4 to 2.8); pain tolerance: mean difference 4.9 (95% CI 5.0 to 4.8)]. Cryotherapy in combination with burst TENS provided greater analgesia compared with the other groups (P<0.001). CONCLUSION: These results support the use of cryotherapy in combination with burst TENS to reduce induced pain, and suggest a potentiating effect when these techniques are combined. No such association was found between cryotherapy and conventional TENS.

Concurrent detection of other respiratory viruses in children shedding viable human respiratory syncytial virus.

Human respiratory syncytial virus (HRSV) is an important cause of respiratory disease. The majority of studies addressing the importance of virus co-infections to the HRSV-disease have been based on the detection of HRSV by RT-PCR, which may not distinguish current replication from prolonged shedding of remnant RNA from previous HRSV infections. To assess whether co-detections of other common respiratory viruses are associated with increased severity of HRSV illnesses from patients who were shedding viable-HRSV, nasopharyngeal aspirates from children younger than 5 years who sought medical care for respiratory infections in Ribeirão Preto (Brazil) were tested for HRSV by immunofluorescence, RT-PCR and virus isolation in cell culture. All samples with viable-HRSV were tested further by PCR for other respiratory viruses. HRSV-disease severity was assessed by a clinical score scale. A total of 266 samples from 247 children were collected and 111 (42%) were HRSV-positive. HRSV was isolated from 70 (63%), and 52 (74%) of them were positive for at least one additional virus. HRSV-positive diseases were more severe than HRSV-negative ones, but there was no difference in disease severity between patients with viable-HRSV and those HRSV-positives by RT-PCR. Co-detection of other viruses did not correlate with increased disease severity. HRSV isolation in cell culture does not seem to be superior to RT-PCR to distinguish infections associated with HRSV replication in studies of clinical impact of HRSV. A high rate of co-detection of other respiratory viruses was found in samples with viable-HRSV, but this was not associated with more severe HRSV infection.

Effectiveness of the ProTaper Universal Retreatment™ system for removing a 10-year-old filling material.

AIM: The aim of the present study was to evaluate the effectiveness of the ProTaper Universal Retreatment™ system and the manual technique for removing a 10-year-old filling material. METHODS: Twenty mesiobuccal canals of mandibular first molars with curvature degrees ranging from 20° to 35° were instrumented by the Double-Flared Instrumentation Technique with the NitiFlex files. The root canals were dried with sterile paper points and filled with gutta-percha and a zinc oxide-eugenol-based sealer using a cold lateral condensation technique. Accesses to the cavities were temporarily sealed with Cavit. The teeth were embedded in gauze containing saline solution, which was renewed every 2 weeks, and were stored at 37 °C in 100% humidity for 10 years. Buccolingual and mesiodistal radiographs were taken to evaluate the quality of the root canal filling. The radiographs were mounted in slide frames to allow them to be evaluated by the three examiners, who were specialists in endodontics. Only the specimens in whom there was agreement between the three evaluators were included in the study. The specimens were divided into 2 groups with 10 root canals each, according to gutta-percha removal techniques: Group 1: ProTaper Universal Retreatment™ system; Group 2: Hedström and K-files. Buccolingual and mesiodistal radiographs were taken and evaluated by three examiners who determined the effectiveness of the removal of the filling material. The presence of material was measured according to a score scale. Data were analyzed statistically by Fisher's exact test at 5% significance level. RESULTS: There were no statistical differences between the two methods in the coronal (P=0.211), and middle (P=0.266) thirds, but there were statistical differences between the two methods in the apical third (P=0.038). CONCLUSION: Not one of the experimental techniques promoted complete removal of the filling materials. The manual technique with K-file and Hedström files achieved better results than the ProTaper Universal Retreatment™ system.

Genetic analyses of Trypanosoma cruzi isolates from naturally infected triatomines and humans in northeastern Brazil.

Trypanosoma cruzi genetic diversity was investigated in 25 isolates (vectors and humans) from the semiarid zone of the State of Rio Grande do Norte, Brazil. Molecular markers (3' region of the 24Salpha rRNA; mitochondrial cytochrome oxidase subunit 2 (COII) gene; spliced leader intergenic region (SL-IR) gene; allelic size microsatellite polymorphism) identified 56% TcIII (100% Panstrongyluslutzi; 50% Triatomabrasiliensis); 40% TcII (91.7% humans; 50% T. brasiliensis) and 4% TcI (human). Microsatellite analysis revealed monoclonal and heterozygous patterns on one or more microsatellite loci in 64% of T. cruzi isolates (92.3% triatomines; 33.3% humans) and 36% putative polyclonal populations (66.7% humans; 7.7% triatomines) by loci SCLE10, SCLE11, TcTAT20, TcAAAT6, all belonging to TcII. Identical T. cruzi polyclonal profiles (88.9%) were detected, mostly from humans. The adaptative natural plasticity of TcII and TcIII and their potential for maintaining human infection in T. brasiliensis were confirmed. Intraspecific and phylogenetic T. cruzi diversity in the sylvatic and domestic transmission cycles in this specific region will provide exclusive control strategies.

Human bocavirus respiratory infections in children.

Human bocavirus (HBoV) was recently identified in respiratory samples from patients with acute respiratory infections and has been reported in different regions of the world. To the best of our knowledge, HBoV has never been reported in respiratory infections in Brazil. Nasopharyngeal aspirates were collected from patients aged <5 years hospitalized in 2005 with respiratory infections in Ribeirão Preto, southeast Brazil, and tested by polymerase chain reaction (PCR) for HBoV. HBoV-positive samples were further tested by PCR for human respiratory syncytial virus, human metapneumovirus, human coronaviruses 229E and OC43, human influenza viruses A and B, human parainfluenza viruses 1, 2 and 3, human rhinovirus and human adenovirus. HBoV was detected in 26/248 (10.5%) children of which 21 (81%) also tested positive for other respiratory viruses. Despite the high rates of co-infections, no significant differences were found between HBoV-positive patients with and without co-infections with regard to symptoms.

Type 2 dens invaginatus in a maxillary lateral incisor: a case report of a conventional endodontic treatment.

Dens invaginatus is a rare malformation of the teeth resulting from the invagination of the tooth crown before biological mineralization occurs. In most cases, the thin or incomplete enamel lining of the invagination cannot prevent the entry of bacteria into the pulp, which leads to pulp necrosis with an eventual periapical inflammatory response. The treatment options include preventive sealing or filling of the invagination, root canal treatment, endodontic apical surgery and extraction. The root canal treatment of such teeth is often complicated because of their anatomical complexity. This case describes a successful non-surgical endodontic treatment of a maxillary lateral incisor with type 2 dens invaginatus with a large periradicular lesion. At follow-up examinations after 6 and 12-months, the tooth was asymptomatic and the healed lesion was evident radiographically

Avaliação neuropsicológica de crianças com hemiparesia congênita e adquirida--resultados preliminares / Neuropsicologic evaluation of children with congenital and acquired hemyparesis--early results

PURPOSE: To present the preliminary results of neuropsychological assessment for children with congenital and acquired hemiparesis with or not seizures. METHODS: Nine children at a age of 5 and 14 years old, were studied individually by one battery of test to neuropsychological assessment of cognitive function, language, gnosia, praxia visuo-motor and memory processing and emotional aspect. RESULTS: Children with hemiparesis demonstrated minimal or severe cognitive dysfuctions, impaired language abilities, poor visuo-motor and memory processing and alteration in emotional aspect. Acquired hemiparesis with seizures in childhood had a severe cognitive deficits, but congenital hemiparesis with or not seizures the neuropsychological assessment demonstrate minimal or moderate cortical deficits. CONCLUSIONS: Theses preliminary results demonstrated that congenital or acquired hemiparesis associated or not with seizures present cortical dysfuctions. The worst results was observed in acquired hemiparesis with epileptic seizures.

[Etiological profile of bacterial meningitis in a small hospital] / Perfil etiológico das meningites bacterianas em um hospital de pequeno porte.

OBJECTIVE: To determine the etiologic profile of cases of meningitis treated at a small hospital in Ribeirão Preto, State of São Paulo, and to compare it to those reported for other communities.METHODS: a retrospective study was conducted on 103 patients admitted from January 1992 to July 1996 with clinical and laboratory diagnosis of bacterial meningitis. The clinical criteria for diagnosis were based on patient history and physical signs and symptoms, and the laboratory criteria were based on cerebrospinal fluid examination (aspect, cytology, biochemistry, Gram staining, culture and countercurrent immunoelectrophoresis) and blood culture.RESULTS: The etiologic agent was identified in 81.5% of cases: Haemophilus influenzae type b in 32%, Neisseria meningitides in 25.2%, Streptococcus pneumoniae in 8.7%, Staphylococcus aureus and epidermidis in 8.7%, and others agents in 6.9%. CONCLUSIONS: The study showed that the cases of bacterial meningitis treated at the Santa Lydia Hospital of Ribeirão Preto are caused by the same agents detected in other places, with Haemophilus influenzae type b being the predominant one. The study also suggests that when many people are involved in the collection of material for laboratory tests, recovery of the agent may become difficult.

Anatomical study of the renal veins observed during 342 living-donor nephrectomies.

The anatomical variations of renal veins observed during 342 nephrectomies in living donors are described, 311 cases on the left side and 31 on the right. The following anatomy of the renocava veins was observed: 1. On the left side the renal vein was always unique (311/311) and had two tributaries (suprarenal and gonadal veins) in 100 per cent and one or more renolumbar veins in 65.27 per cent, encircling the aorta in 1.07 per cent, was retroaortic in 1.4 per cent; and the inferior vena cava was double in 0.64 per cent; B- on the right side the renal vein was double in 29 per cent (9/31) and had only one tributary (gonadal vein) in one case, for 3.22 per cent (1/31); three or more renal veins in 9.7 per cent (3/31). We concluded that the left renal vein is always unique, presenting variations principally in its tributaries and trajectory. On the right side, the renal vein was double or triple in 38.79 per cent.

Postnephrectomy arteriovenous fistula.

The development of the postnephrectomy arteriovenous fistula (PNAVF) between the renal vessels stumps is rare. Here we present a case report of PNAVF, and review the diagnosis, treatment and prevention. The most common clinical features include a loud murmur over the previous nephrectomy scar, and heart failure resistant to common medical treatment. A 58-year-old white woman was admitted to the hospital for a complete evaluation of an unexplained congestive heart failure with no response to common medical treatment. She had had a right nephrectomy for pyonephrosis 13 years before. The diagnosis of PNAVF was suspected because over the right lumbar region a definite trill was palpated, and on auscultation a harsh, machinery-like murmur was heard. The diagnosis was confirmed by aortogram and selective renal arteriography. In May 1989, the right arteriovenous was excised through a right subcostal transperitoneal approach. The renal vessel stumps were individually ligated and sutured separately close to aorta and vena cava. The patient's postoperative course was entirely uneventful in the following seven years. We conclude that during nephrectomy, the renal vessels should be ligated separately, and the transfixation in mass of the stumps avoided to prevent arteriovenous fistula.

Methamidophos: an anticholinesterase without significant effects on postsynaptic receptors or transmitter release.

Methamidophos (O,S-dimethyl phosphoroamidothiolate, Tamaron), an organophosphate (OP) anticholinesterase of limited toxicity, is widely used as an insecticide and acaricide. To provide additional insight into the molecular basis of its action, we have used electrophysiological and biochemical techniques to study the effects of methamidophos on the neuromuscular junction of rat and frog and on the central nervous system of rat. Methamidophos has a relatively weak inhibitory action on cholinesterases in rat diaphragm muscle, brain and hippocampal homogenates, with IC50 values on the order of 20-20 microM. An even weaker anticholinesterase activity was found in frog muscle homogenates, with the IC50 being above 300 microM. As further evidence of anticholinesterase activity, methamidophos (1-100 microM) was able to reverse the blockade by d-tubocurarine (0.5-0.7 microM) of neuromuscular transmission in rat phrenic nerve-hemidiaphragm preparations. Inhibition of cholinesterase activity by methamidophos was long lasting, which is consistent with the formation by the agent of a covalent bond with the enzyme's active serine residue. The action was also slowly reversible, which suggests spontaneous reactivation of the enzyme. electrophysiological studies at the rat neuromuscular junction showed that, due to its anticholinesterase activity, methamidophos increased the amplitude and prolonged the decay phase of nerve-evoked and spontaneous miniature end-plate potentials. In contrast to other OP compounds, e.g., paraoxon (Rocha et al., 1996a), methamidophos did not affect neurotransmitter release, nor did it interact directly with the muscle nicotinic acetylcholine receptor. Moreover, it contrast to paraoxon, methamidophos did not affect the whole-cell currents induced by application of acetylcholine, glutamate or gamma-aminobutyric acid recorded to cultured hippocampal neurons. Based on these data, methamidophos appears to have a selective effect on cholinesterase.

[Presence of antibodies against Venezuelan equine encephalitis virus subtype VI in patients with acute febrile illness]. / Presencia de anticuerpos contra el virus de la encefalitis equina venezolana subtipo VI en pacientes con enfermedad aguda febril.

In Argentina, there is no record of human cases produced by Dengue virus (Flavivirus), but Paraguay and Brasil (neighbouring countries) have notified human outbreaks of Dengue Haemorrhagic Fever. In this report, we inform the serological results of a limited human outbreak of a Dengue-like acute illness that occurred in General Belgrano Island, Formosa, Argentina in April 1989. This island is 35 km far from Clorinda city of Paraguay river, with a human population of 150 inhabitants. The weather of this area is humid with abundant rainfall, favouring mosquitoes proliferation. Two samples of serum from 28 human notified cases were studied using hemagglutination inhibition test (HI), complement fixation (CF), and plaque reduction neutralization (NT) test in Vero cell cultures. All tested sera were negative to Dengue, St. Louis encephalitis, Yellow Fever, Bussuquara, Rocio, Eastern and Western Equine Encephalitis arboviruses as well as Influenza and Rubella viruses. By contrast, infection with Venezuelan equine encephalitis virus (VEE), subtype VI-AG80-663 strain was demonstrated (34.5% positive by HI, 39.1% by CF and 51.6% by NT). Seroconversion was detected by NT in six cases and only five were positive by CF. The 26.8% of the sera reacted also with VEE subtype I AB by NT. Considering that no cross reaction were detected in NT with these two subtypes, our results suggest that both viruses are concomitantly circulating in the studied area. Furthermore, the seroconversions detected with AG80-663 strain firmly indicate that during the outbreak this virus subtype was circulating in the island, although we could not assure that it was the causal agent of the acute disease.

Presencia de anticuerpos contra el virus de la encefalitis equina venezolana subtipo VI en pacientes con enfermedad aguda febril. / [Presence of antibodies against Venezuelan equine encephalitis virus subtype VI in patients with acute febrile illness]

In Argentina, there is no record of human cases produced by Dengue virus (Flavivirus), but Paraguay and Brasil (neighbouring countries) have notified human outbreaks of Dengue Haemorrhagic Fever. In this report, we inform the serological results of a limited human outbreak of a Dengue-like acute illness that occurred in General Belgrano Island, Formosa, Argentina in April 1989. This island is 35 km far from Clorinda city of Paraguay river, with a human population of 150 inhabitants. The weather of this area is humid with abundant rainfall, favouring mosquitoes proliferation. Two samples of serum from 28 human notified cases were studied using hemagglutination inhibition test (HI), complement fixation (CF), and plaque reduction neutralization (NT) test in Vero cell cultures. All tested sera were negative to Dengue, St. Louis encephalitis, Yellow Fever, Bussuquara, Rocio, Eastern and Western Equine Encephalitis arboviruses as well as Influenza and Rubella viruses. By contrast, infection with Venezuelan equine encephalitis virus (VEE), subtype VI-AG80-663 strain was demonstrated (34.5

positive by HI, 39.1

by CF and 51.6

by NT). Seroconversion was detected by NT in six cases and only five were positive by CF. The 26.8

of the sera reacted also with VEE subtype I AB by NT. Considering that no cross reaction were detected in NT with these two subtypes, our results suggest that both viruses are concomitantly circulating in the studied area. Furthermore, the seroconversions detected with AG80-663 strain firmly indicate that during the outbreak this virus subtype was circulating in the island, although we could not assure that it was the causal agent of the acute disease.