Liver fibrosis progression in HIV/hepatitis C virus coinfected patients with normal aminotransferases levels

INTRODUCTION: Approximately 30% of hepatitis C virus (HCV) monoinfected patients present persistently normal alanine aminotransferase (ALT) levels. Most of these patients have a slow progression of liver fibrosis. Studies have demonstrated the rate of liver fibrosis progression in hepatitis C virus-human immunodeficiency virus (HCV-HIV) coinfected patients is faster than in patients infected only by HCV. Few studies have evaluated the histological features of chronic hepatitis C in HIV-infected patients with normal ALT levels. METHODS: HCV-HIV coinfected patients (HCV-RNA and anti-HIV positive) with known time of HCV infection (intravenous drugs users) were selected. Patients with hepatitis B surface antigen (HBsAg) positive or hepatitis C treatment before liver biopsy were excluded. Patients were considered to have a normal ALT levels if they had at least 3 normal determinations in the previous 6 months prior to liver biopsy. All patients were submitted to liver biopsy and METAVIR scale was used. RESULTS: Of 50 studied patients 40 (80%) were males. All patients were treated with antiretroviral therapy. The ALT levels were normal in 13 (26%) patients. HCV-HIV co-infected patients with normal ALT levels had presented means of the liver fibrosis stages (0.77±0.44 versus 1.86±1.38; p<0.001) periportal inflammatory activity (0.62±0.77 versus 2.24±1.35; p<0.001) and liver fibrosis progression rate (0.058±0.043 fibrosis unit/year versus 0.118±0.102 fibrosis unit/year) significantly lower as compared to those with elevated ALT. CONCLUSIONS: HCV-HIV coinfected patients with persistently normal ALTs showed slower progression of liver fibrosis. In these patients the development of liver cirrhosis is improbable.

Aminotransferases activity in the hemolymph of Bradybaena similaris (Gastropoda, Xanthonychidae) under starvation

Aminotransferases (GOT and GPT) activities in the hemolymph of Bradybaena similaris under experimental condition of starvation were studied. At the 10th day of starvation, GOT activity was 416.6% higher than that observed in the fed snails, being reduced and ranging values near to that shown by the control group onwards. GPT activity only varied significantly at the day-30 of starvation. The results were discussed.

Enzyme engineering of aminotransferases for improved activity and thermostability

The production by biosynthesis of optically active amino acids and amines satisfies the pharmaceutical industry in its demand for chiral building blocks for the synthesis of various pharmaceuticals. Among several enzymatic methods that allow the synthesis of optically active aminoacids and amines, the use of minotransferase is a promising one due to its broad substrate specificity and no requirement for external cofactor regeneration. The synthesis of chiral compounds by aminotransferases can be done either by asymmetric synthesis starting from keto acids or ketones, and by kinetic resolution starting from racemic aminoacids or amines. The asymmetric synthesis of substituted (S)-aminotetralin, an active pharmaceutical ingredient (API), has shown to have two major factors that contribute to increasing the cost of production. These factors are the raw material cost of biocatalyst used to produce it and product loss during biocatalyst separation. To minimize the cost contribution of biocatalyst and to minimize the loss of product, two routes have been chosen in this research: 1. To engineer the aminotransferase biocatalyst to have greater specific activity, and 2. Improve the engineering of the process by immobilization of biocatalyst in calcium alginate and addition of cosolvents. An (S)-aminotransferase (Mutant CNB03-03) was immobilized, not as purified enzyme but as enzyme within spray dried cells, in calcium alginate beads and used to produce substituted (S)-aminotetralin at 50 °C and pH 7 in experiments where the immobilized biocatalyst was recycled. Initial rate of reaction for cycle 1 (6 hr duration) was determined to be 0.258 mM/min, for cycle 2 (20 hr duration) it decreased by ~50% compared to cycle 1, and for cycle 3 (20 hr duration) it decreased by ~90% compared to cycle 1 (immobilized preparation consisted of 50 mg of spray dried cells per gram of calcium alginate). Conversion to product for each cycle decreased as well, from 100% in cycle 1 (About 50 mM), 80% in cycle 2, and 30% after cycle 3. This mutant was determined to be deactivated at elevated temperatures during the reaction cycle and was not stable enough to allow multiple cycles in its immobilized form. A new mutant aminotransferase was isolated by applying error-prone polymerase chain reaction (PCR) on the gene coding for this enzyme and screening/selection: CNB04-01. This mutant showed a significant improvement in thermostability in comparison to CNB03-03. The new mutant was immobilized and tested under similar reaction conditions. Initial rate remained fairly constant (0.2 mM/min) over four cycles (each cycle with a duration of about 20 hours) with the mutant retaining almost 80% of initial rate in the fourth cycle. The final product concentrations after each cycle did not decrease during recycle experiments. Thermostability of CNB04-01 was much improved compared to CNB03-03. Under the same reaction conditions as stated above, the addition of co-solvents was studied in order to increase substituted tetralone solubility. Toluene and sodium dodecylsulfate (SDS) were used. SDS at 0.01% (w/v) allowed four recycles of the immobilized spray dried cells of CNB04-01, always reaching higher product concentration (80-85 mM) than the system with toluene at 3% (v/v) -70 mM-. The long term activity of immobilized CNB04-01 in a system with SDS 0.01% (w/v) at 50 °C, pH 7 was retained for three cycles (20 to 24 hours each one), reaching always final product concentration between 80-85 mM, but dropping precipitously in the fourth cycle to a final product concentration of 50 mM. Although significant improvement of immobilization on productivity and stability were observed using CNB04-01, another observation demonstrated the limitations of an immobilization strategy on reducing process costs. After analyzing the results of this experiment it was seen that a sudden drop occurred on final product concentration after the third recycle. This was due to product accumulation inside the immobilized preparation. In order to improve the economics of the process, research was focused on developing a free enzyme with an even higher activity, thus reducing raw material cost as well as improving biomass separation. A new enzyme was obtained (CNB05-01) using error-prone PCR and screening using as a template the gene derived from the previous improved enzyme. This mutant was determined to have 1.6 times the initial rate of CNB04-01 and had a higher temperature optimum (55°). This new enzyme would allow reducing enzyme loading in the reaction by five-fold compared to CNB03-03, when using it at concentration of one gram of spray dried cells per liter (completing the reaction after 20-24 hours). Also this mutant would allow reducing process time to 7-8 hours when used at a concentration of 5 grams of spray dried cells per liter compared to 24 hours for CNB03-03, assuming that the observations shown before are scalable. It could be possible to improve the economics of the process by either reducing enzyme concentration or reducing process time, since the production cost of the desired product is primarily a function of both enzyme concentration and process time.

Serum Aminotransferases in Thai Children With Dengue Infection

Background: Hepatic manifestations are one of the unusual manifestations of dengue infection. Objectives: We conducted this study in order to study the pattern of serum aminotransferases and sequential changes before and after shock in Thai children with dengue infection. Patients and Methods: Children who were clinically and serologically diagnosed as dengue infection and were admitted to King Chulalongkorn Memorial Hospital during a peroid of one year were enrolled. They were clinically classified into a non-shock group and a shock group. The majority of serum aminotransferases including aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were obtained within a week after the onset of fever and until 3 days after shock in the shock group. Student t-test and median in boxplot form were used for statistical analysis. Results: We enrolled 127 children with a mean age of 7.6 ± 3.6 years. The incidence of abnormal AST and ALT levels was 97.4% and 50.0% in the shock group, and 91.8% and 44.9% in the non-shock group respectively. 29% and 15.4% of the patients in shock group and only 10.2% and 4.1% in non-shock group had the respective AST and ALT levels > 200 U/L. Serum aminotransferase levels were significantly higher in the shock group when compared to the non-shock group. AST tended to increase starting from one day before shock and continued to increase within a few days whereas ALT was less likely to be affected. Conclusions: Elevated serum aminotransferases are a common finding in children with dengue infection and the levels of AST are higher than those of ALT. Patients with shock have significantly higher aminotransferase levels that increase up to 3 days after shock.

Análise morfológica e fisiológica dos fígados e rins de ratas prenhes e seus fetos tratados pela associação zidovudina, lamivudina e ritonavir durante toda a prenhez

OBJETIVO: avaliar os efeitos da administração da associação zidovudina-lamivudina-ritonavir nos fígados e rins de ratas prenhes e seus conceptos do ponto de vista morfológico e fisiológico. MÉTODOS: 40 ratas albinas prenhes foram aleatoriamente divididas em 4 grupos: 1 controle (Ctrl: controle de veículo) e 3 experimentais (Exp1x, Exp3x e Exp9x). Estes últimos foram tratados por solução oral de zidovudina/lamivudina/ritonavir (Exp1x: 10/5/20 mg/kg; Exp3x: 30/15/60 mg/kg; Exp9x: 90/45/180 mg/kg). As drogas e o veículo foram administrados por gavagem, desde o 1º até o 20º dia de prenhez. No último dia do experimento, todos os animais foram anestesiados e sangue foi retirado da cavidade cardíaca para avaliação sérica das enzimas aspartato aminotransferase (AST) e alanina aminotransferase (ALT), por método calorimétrico, bem como da ureia, determinada por método cinético-enzimático, e creatinina, por método cinético-colorimétrico. Em seguida, fragmentos dos fígados e rins maternos e fetais foram coletados, fixados em formol a 10% e processados segundo os métodos histológicos para inclusão em parafina. Cortes com 5 µm de espessura foram corados pela hematoxilina-eosina (HE) e analisados por microscopia de luz. Na leitura das lâminas, considerou-se o padrão de normalidade para fígado e rins, tais como: hepatócitos, espaço porta íntegros e veias hepáticas bem definidas. Nos rins, a presença de corpúsculos renais, túbulos contorcidos e alças de Henle típicos. Nos fígados fetais considerou-se, ainda, a morfologia das células da linhagem eritrocitária nas diferentes fases do desenvolvimento, bem como os megacariócitos. Quando houve alteração da coloração padrão estabelecida para as estruturas hepáticas e renais, alteração na morfologia de núcleos, rompimento de limites de alguma organela citoplasmática, presença de congestão vascular, tudo isso foi entendido como provavelmente provocado pelas drogas em sua(s) dose(s) de aplicação. A avaliação estatística foi realizada por análise de variância (ANOVA), completada pelo teste de Tukey-Kramer (p<0,05). RESULTADOS: os fígados maternos dos grupos Ctrl, Exp1x e Exp3x mostraram hepatócitos típicos, espaço porta íntegros e veias hepáticas com aspecto normal. No fígado materno do grupo Exp9x, foram encontrados hepatócitos com sinais de atrofia e apoptose (eosinofilia citoplasmática e núcleos picnóticos). Além disso, identificou-se vasodilatação dos capilares sinusoides (congestão). Os rins maternos dos grupos Ctrl e Exp1x apresentaram-se normais, com corpúsculos renais, túbulos contorcidos e alças de Henle típicos. Já nos grupos Exp3x e Exp9x, foram encontrados congestão vascular, glomérulos pequenos ricos em células contendo núcleos hipercromáticos, sendo mais intensos no Exp9x. Com relação aos fígados e rins fetais, não foram observadas alterações morfológicas ou fisiológicas nos grupos estudados. Encontrou-se aumento significante nos níveis da AST (305,70±55,80; p<0,05) e da creatinina (0,50±0,09; p<0,05) no grupo Exp9x. CONCLUSÕES: nossos resultados evidenciam que a administração da associação zidovudina/lamivudina/ritonavir a ratas prenhes em altas doses causa alterações morfológicas e funcionais nos fígados e rins maternos. Não houve alterações nem morfológicas nem fisiológicas nos fígados e rins fetais.

Combination of N-acetylcysteine and metformin improves histological steatosis and fibrosis in patients with non-alcoholic steatohepatitis

Aim: There is no proven medical therapy for the treatment of non-alcoholic steatohepatitis (NASH). Oxidative stress and insulin resistance are the mechanisms that seem to be mostly involved in its pathogenesis. The aim of our study was to evaluate the efficacy of N-acetylcysteine (NAC) in combination with metformin (MTF) in improving the aminotransferases and histological parameters (steatosis, inflammation, hepatocellular ballooning, and fibrosis) after 12 months of treatment. Methods: Twenty consecutive patients (mean age 53 +/- 2 years [36-68] and body mass index [BMI] 29 [25-35]) with biopsy-proven NASH were enrolled in the study. NAC (1.2 g/day) and MTF (850-1000 mg/day) were given orally for 12 months. All patients underwent evaluation of serum aminotransferases, fasting lipid profile and serum glucose, anthropometric parameters, and nutritional status at 0 and 12 months. A low calorie diet was prescribed for all patients. Results: Serum alanine aminotransferase, high-density lipoprotein, insulin, and glucose concentrations and thehomeostasis model assessment-insulin resistance (HOMA-IR) index were reduced significantly at the end of study (P < 0.05). The BMI declined, but without statistical significance. Aspartate aminotransferase, gamma-glutamyl transferase, alkaline phosphatase, cholesterol, and triglycerides levels were not altered with the treatment. Liver steatosis and fibrosis decreased (P < 0.05), but no improvement was noted in lobular inflammation or hepatocellular ballooning. The NASH activity score was significantly improved after treatment. Conclusion: Based on the biochemical and histological evidence in this pilot study, NAC in combination with MTF appears to ameliorate several aspects of NASH, including fibrosis. Further studies of this form of combination therapy are warranted to assess its potential efficacy.

Influence of Biliary Drainage on the Repair of Hepatic Lesions in Biliary Fibrosis

Background. Bilioduodenal (BD) and biliojejunal (BJ) derivation induce enterobiliary reflux and bile stasis. Decompression of the excluded loop of the Roux-en-Y (BJD) was proposed to minimize these effects. The aim of this study was to compare the influence of these three modalities of biliary bypass on hepatic lesion repair in rats with secondary biliary fibrosis. Materials and Methods. Rats with 15 d of biliary obstruction underwent BD, BJ, and BJD drainage and were compared with a group submitted to simulated operation (SO) and biliary obstruction (CBO). The serum values of total and fractional bilirubin, alkaline phosphatase (ALP), and aminotransferases (AST and ALT), as well as hepatobiliointestinal excretion determined with (99m)Tc-Disida, were used for comparison. In addition, we used morphometric analyses to estimate the mass of the hepatocytes, bile ducts, and liver fibrosis. We also counted hepatic stellate cells (SC). Results. For each of the three modalities of biliary drainage, there were significant reductions in bilirubin, AST, ALP, and the number of SCs. The recovery of the estimated mass of all histologic components occurred only after BJ and BJD; in the BD group, the estimated hepatocyte mass was reduced compared with the SO group. The residual hepatic radioactivity of (99m)Tc-Disida was greater in the BJD group than in the SO group. Conclusions. The interposition of the jejunal loop between the biliary tree and the intestine may slow hepatobiliary clearance of radioactivity, even though it provides the resolution of cholestasis and is effective in recovering from hepatic lesions. (C) 2011 Elsevier Inc. All rights reserved.

Effect of NF kappa B Inhibition by CAPE on Skeletal Muscle Ischemia-Reperfusion Injury

Background/Aims. Nuclear factor kappa B (NF kappa B) plays important role in the pathogenesis of skeletal muscle ischemia/reperfusion (I/R) injury. Caffeic acid phenyl ester (CAPE), a potent NF kappa B inhibitor, exhibits protective effects on I/R injury in some tissues. In this report, the effect of CAPE on skeletal muscle I/R injury in rats was studied. Methods. Wistar rats were submitted to sham operation, 120-min hindlimb ischemia, or 120-min hindlimb ischemia plus saline or CAPE treatment followed by 4-h reperfusion. Gastrocnemius muscle injury was evaluated by serum aminotransferase levels, muscle edema, tissue glutathione and malondialdehyde measurement, and scoring of histological damage. Apoptotic nuclei were determined by a terminal uridine deoxynucleotidyl transferase dUTP nick end labeling assay. Muscle neutrophil and mast cell accumulation were also assessed. Lipoperoxidation products and NF kappa B were evaluated by 4-hydroxynonenal and NF kappa B p65 immunohistochemistry, respectively. Results. Animals submitted to ischemia showed a marked increase in aminotransferases after reperfusion, but with lower levels in the CAPE group. Tissue glutathione levels declined gradually during ischemia to reperfusion, and were partially recovered with CAPE treatment. The histological damage score, muscle edema percentage, tissue malondialdehyde content, apoptosis index, and neutrophil and mast cell infiltration, as well as 4-hydroxynonenal and NF kappa B p65 labeling, were higher in animals submitted to I/R compared with the ischemia group. However, the CAPE treatment significantly reduced all of these alterations. Conclusions. CAPE was able to protect skeletal muscle against I/R, injury in rats. This effect may be associated with the inhibition of the NF kappa B signaling pathway and decrease of the tissue inflammatory response following skeletal muscle I/R. (C) 2009 Elsevier Inc. All rights reserved.

Antibodies against non-structural c100/3 and structural core antigen of hepatitis C virus (HCV) in hemodialysis patients

Two groups of patients undergoing hemodialysis (HD) maintenance were evaluated for their antibody response to non-structural c100/3 protein and structural core protein of hepatitis C virus (HCV). Forty-six patients (Group 1) never presented liver abnormalities during HD treatment, while 52 patients (Group 2) had either current or prior liver enzyme elevations. Prevalence rates of 32.6% and 41.3% were found for anti-c100/3 and anti-HCV core antibodies, respectively, in patients with silent infections (Group 1). The rate of anti-c100/3 in patients of Group 2 was 71.15% and reached 86.5% for anti-HCV core antibodies. The recognition of anti-c100/3 and anti-core antibodies was significantly higher in Group 2 than in Group 1. A line immunoassay composed of structural and non-structural peptides was used as a confirmation assay. HBV infection, measured by the presence of anti-HBc antibodies, was observed in 39.8% of the patients. Six were HBsAg chronic carriers and 13 had naturally acquired anti-HBs antibodies. The duration of HD treatment was correlated with anti-HCV positivity. A high prevalence of 96.7% (Group 2) was found in patients who underwent more than 5 years of treatment. Our results suggest that anti-HCV core ELISA is more accurate for detecting HCV infection than anti-c100/3. Although the risk associated with the duration of HD treatment and blood transfusion was high, additional factors such as a significant non-transfusional spread of HCV seems to play a role as well. The identification of infective patients by more sensitive methods for HCV genome detection should help to control the transmission of HCV in the unit under study.

Hepatitis B and C virus markers among patients with hepatosplenic mansonic schistosomiasis

PURPOSE: To evaluate the frequency and the consequences of the co-infection of hepatitis B and C viruses in patients with hepatosplenic schistosomiasis (HSS). METHODS: B and C serologic markers, exposure to risk factors, biochemical assays, upper gastrointestinal endoscopies, and abdominal ultrasonograms were evaluated in 101 patients with HSS from 1994 to 1997. Whenever possible, PCR was tested and histopathological studies were reviewed. RESULTS: At least one HBV virus marker was found in 15.8%, and anti-HCV was detected in 12.9% of the subjects. The seropositive subjects tended to be older than the seronegative ones. A history of blood transfusion was significantly related to the presence of anti-HCV. Three (18.75%) out of 16 subjects exposed to B virus were HBsAg positive. Eleven (84.6%) out of thirteen patients who were anti-HCV positive demonstrated viral activity. Patients with ongoing viral infection presented a higher average level of liver aminotransferases, a higher frequency of cell decompensation and a higher rate of chronic hepatitis. Portal hypertension parameters were not influenced by viral exposure. CONCLUSIONS: The rate of hepatitis B and C viruses serologic markers observed in the patients with HSS was higher than the control group. The co-infection was responsible for a higher frequency of cell decompensation.

Dapsone hypersensitivity syndrome in an adolescent during treatment during of leprosy

A 12 y old girl was admitted 24 days after start a WHO multidrug therapy scheme for multibacillary leprosy (dapsone, clofazimine and rifampicin) with intense jaundice, generalized lymphadenopathy, hepatoesplenomegaly, oral erosions, conjunctivitis, morbiliform rash and edema of face, ankles and hands. The main laboratory data on admission included: hemoglobin, 8.4 g/dL; WBC, 15,710 cells/mm³; platelet count, 100,000 cells/mm³; INR = 1.49; increased serum levels of aspartate and alanine aminotransferases, gamma-glutamyl transpeptidase, alkaline phosphatase, direct and indirect bilirubin. Following, the clinical conditions had deteriorated, developing exfoliative dermatitis, shock, generalized edema, acute renal and hepatic failure, pancytopenia, intestinal bleeding, pneumonia, urinary tract infection and bacteremia, needing adrenergic drugs, replacement of fluids and blood product components, and antibiotics. Ten days after admission she started to improve, and was discharged to home at day 39th, after start new supervised treatment for leprosy with clofazimine and rifampicin, without adverse effects. This presentation fulfils the criteria for the diagnosis of dapsone hypersensitivity syndrome (fever, generalized lymphadenopathy, exfoliative rash, anemia and liver involvement with mixed hepatocellular and cholestatic features). Physicians, mainly in geographical areas with high prevalence rates of leprosy, should be aware to this severe, and probably not so rare, hypersensitivity reaction to dapsone.

Acute inflammatory demyelinating polyradiculoneuropathy (Guillain-Barré syndrome) following dengue fever

This paper reports a case of dengue in a six-year-old female child who suddenly developed excruciating headaches, fever, myalgia and paresis. Laboratory examinations included blood count, platelet count, biochemical tests (BUN, creatinine, aminotransferases, and total bilirubin and bilirubin fractions) and specific IgM titers (enzyme-immunoassay with recombinant tetravalent dengue). After ten days of hospitalization and having already been in a home environment, a new clinical image emerged, characterized by dysphagia, dysphonia, weakness, peripheral facial palsy and paresthesia. The diagnosis of Guillain-Barré Syndrome was based on clinical findings, cerebrospinal fluid examination, electrophysiological findings and the exclusion of other pathologies. Our case, as some shown in previous reports, calls attention to the possibility that Guillain-Barré Syndrome may occur in association with dengue.

A clinico-pathological study of 163 untreated cases of chronic hepatitis C

We performed a clinico-pathological study of 163 untreated cases of chronic hepatitis C. Eighty five percent of the patients were clinically asymptomatic and their physical examinations sbowed unremarkable or minimal changes at the time of the liver biopsy Liver function tests tended to present slight abnormalities, involving mild elevations of the activity of the aminotransferases and gamma-glutamil transferase levels. In spite of these mild abnormalities advanced chronic liver disease ivas histologically detected in eighty nine percent of the patients, mainly showing chronic active hepatitis. The most characteristic histological finding ivas an interlobular bile duct damage which correlated with the presence of tymphoid aggregates in the portal tracts and with the development of fibrosis.

Estudo comparativo entre estibogluconato de sódio BP 88® e antimoniato de meglumina no tratamento da leishmaniose cutânea II. Toxicidade bioquímica e cardíaca

Foi avaliada a toxicidade de dois antimoniais pentavalentes em 111 pacientes com leishmaniose cutânea. Quarenta e sete pacientes receberam antimoniato de meglumina (Grupo I) e 64 pacientes, estibogluconato de sódio BP 88® (Grupo II), 20mg SbV/kg/dia por 20 dias. Realizou-se a avaliação de aminotransferases, fosfatase alcalina, amilase, creatinina, uréia, exame de urina e eletrocardiograma, antes do tratamento e no décimo e vigésimo dias. Observou-se maior freqüência de valores anormais de aminotransferases no décimo e vigésimo dias de tratamento no grupo II (p < 0,001) e maior proporção de valores anormais de amilase no décimo dia no mesmo grupo (p < 0,001). Houve maior variação dos níveis de aminotransferases, fosfatase alcalina e amilase nos primeiros dez dias no grupo II (p < 0,01). No vigésimo dia observou-se maior variação nos níveis de aminotransferases no grupo II (p = 0,02 e p = 0,03, respectivamente). Quarenta e três porcento dos pacientes do grupo I e 54% dos pacientes do grupo II apresentaram alterações eletrocardiográficas (p = 0,30).

Yellow fever virus isolated from a fatal post vaccination event: an experimental comparative study with the 17DD vaccine strain in the Syrian hamster (Mesocricetus auratus)

In order to investigate the pathogenicity of the virus strain GOI 4191 that was isolated from a fatal adverse event after yellow fever virus (YFV) vaccination, an experimental assay using hamsters (Mesocricetus auratus) as animal model and YFV 17DD vaccine strain as virus reference was accomplished. The two virus strains were inoculated by intracerebral, intrahepatic and subcutaneous routes. The levels of viremia, antibody response, and aminotransferases were determined in sera; while virus, antigen and histopathological changes were determined in the viscera. No viremia was detected for either strain following infection; the immune response was demonstrated to be more effective to strain GOI 4191; and no significant aminotransferase levels alterations were detected. Strain GOI 4191 was recovered only from the brain of animals inoculated by the IC route. Viral antigens were detected in liver and brain by immunohistochemical assay. Histothological changes in the viscera were characterized by inflammatory infiltrate, hepatocellular necrosis, and viral encephalitis. Histological alterations and detection of viral antigen were observed in the liver of animals inoculated by the intrahepatic route. These findings were similar for both strains used in the experiment; however, significant differences were observed from those results previously reported for wild type YFV strains.