Clarice Weis Arns

Infection and apparent invasion of vero cells by Paracoccidioides brasiliensis

Paracoccidioides brasiliensis probably uses many different mechanisms to establish itself in the host and cause disease. In this work, we assess an in vitro model system which uses cultured mammalian cells to investigate the virulence factors of P. brasiliensis. We were able to demonstrate an invasion process of the yeast form of this fungus in Vero cell cultures. We deduced that the overall invasive process involved three steps: adhesion, followed by invasion of individual epithelial cells and spread to adjacent cells.

Respiratory syncytial virus (RSV) in infants hospitalized for acute lower respiratory tract disease: incidence and associated risks

Respiratory syncytial virus (RSV) is one of the main causes of acute lower respiratory tract infections worldwide. We examined the incidence and associated risks for RSV infection in infants hospitalized in two university hospitals in the state of São Paulo. We made a prospective cohort study involving 152 infants hospitalized for acute lower respiratory tract infections (ALRTI) in two university hospitals in Campinas, São Paulo, Brazil, between April and September 2004. Clinical and epidemiological data were obtained at admission. RSV was detected by direct immunofluorescence of nasopharyngeal secretions. Factors associated with RSV infection were assessed by calculating the relative risk (RR). The incidence of RSV infection was 17.5%. Risk factors associated with infection were: gestational age less than 35 weeks (RR: 4.17; 95% confidence interval (CI) 2.21-7.87); birth weight less than or equal to 2,500 grams (RR: 2.69; 95% CI 1.34-5.37); mothers educational level less than five years of schooling (RR: 2.28; 95% CI 1.13-4.59) and pulse oximetry at admission to hospital lower than 90% (RR: 2.19; 95% CI 1.10-4.37). Low birth weight and prematurity are factors associated with respiratory disease due to RSV in infants. Low educational level of the mother and poor socioeconomic conditions also constitute risk factors. Hypoxemia in RSV infections at admission indicates potential severity and a need for early oxygen therapy.

Characterization of bovine respiratory syncytial virus isolated in Brazil

This paper presents the first isolation of bovine respiratory syncytial virus in Brazil and its physicochemical, morphological and molecular characterization. The virus was isolated from 33 samples of nasotracheal secretions, successively inoculated into a Madin-Darby bovine kidney cell culture, which was characterized by physicochemical tests and morphological observation by electron microscopy. The Brazilian sample is an RNA pleomorphic, enveloped, thermolabile and non-hemagglutinating spicular virus. Reverse transcription, followed by nested polymerase chain reaction (nRT-PCR) assay was carried out using oligonucleotides B1, B2A, B3 and B4 for the fusion proteins (F) and B5A, B6A, B7A and B8 for the attachment protein (G). The nRT-PCR-F amplified a fragment of 481 bp corresponding to part of the gene that codes for protein F, whereas nRT-PCR-G amplified a fragment of 371 bp, in agreement with part of the G gene. The virus isolated from Brazilian samples in this study corresponded to the bovine respiratory syncytial virus, and RT-PCR proved to be useful for the diagnosis of bovine clinical samples.

Replication of classical infectious bursal disease virus in the chicken embryo related cell line.

Infectious bursal disease (IBD) is an acute, highly contagious viral disease. The diagnosis of IBD depends on time-consuming and costly procedures, like virus isolation on chick embryos and histopathological examination. A double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA), immunoperoxidase and reverse transcription polymerase chain reaction (RT-PCR) were applied in this study to detect classical IBD virus (IBDV) after three blind passages of the Lukert strain on chicken embryo related (CER) cell monolayer after different periods of infection: 6, 12, 24 and 48h. Cytophatic effects were most evident 12 h post-infection (p.i.) but were observed at 6 h p.i. The maximum discrimination between IBDV-infected and uninfected cell suspensions obtained by the use of DAS-ELISA for virus detection corresponded to 0.597 ± 0.02 and 0.010 ± 0.01 after 12 h p.i., respectively. The RT-PCR was performed using the set of primers A3.1 and A3.2 to amplify the VP2 region of the IBDV genome. This molecular technique demonstrated that from 6h p.i., it was possible to detect the viral RNA. The results show that the CER cell line can be used for classical IBDV propagation, confirmed by the DAS-ELISA, immunoperoxidase and RT-PCR assay.

Molecular characterization of Brazilian avian pneumovirus isolates: comparison between immunochemiluminescent Southern blot and nested PCR

Avian pneumovirus (APV) causes acute respiratory tract infection both in turkeys (turkey rhinotracheitis) and chickens (swollen head syndrome (SHS)) with sudden onset and rapid spread through the flocks. In this study, an immunochemiluminescent Southern blot RT-PCR assay was employed to detect a F gene transcript of the APV in two European turkey isolates and two Brazilian chicken isolates. Limiting dilution PCR was carried out to compare the sensitivity of immunochemiluminescent Southern blot assay and nested PCR assay (nPCR). The sensitivity and specificity of immunochemiluminescent Southern blot RT-PCR assay were comparable to that of nPCR, and at least 100 fold more sensitive than a single PCR amplification. Sequence analysis of the 175 bp product of the F gene revealed 100% identity with APV sequences described earlier.

Genetic variability in the G protein gene of human respiratory syncytial virus isolated from the Campinas metropolitan region, Brazil.

Human respiratory syncytial virus (hRSV) is recognized as the most important viral agent of serious respiratory tract diseases in the pediatric population worldwide. A prospective study for hRSV was conducted in children ageing less than 1 year admitted in two university hospitals in Campinas, São Paulo, Brazil. The aim of the present study was to investigate the genetic variability of both A and B subgroups of hRSV isolated during an epidemic period in the Campinas metropolitan region, Brazil, by sequencing a variable region of the G protein gene. Phylogenetic trees were constructed from alignments of sequences available in the GenBank database and Brazil isolates for hRSV A and B. The data demonstrate that Brazilian isolates clusters together with A and B viruses from Kenya, New Zealand, South Africa, West Virginia, United States (CH, Rochester), and other Brazilian isolates. Phylogenetic analysis of subgroup A isolates showed that the sequences obtained on the present study falls on three clusters, namely GA2, GA5, and SAA1 that co‐circulate during the analyzed period. Subgroup B isolates detected belongs to three genotypes, GB3 (SAB3) and BA (BAIII). Different subgroup B genotypes were detected and BA isolates present in our samples showed some degree of genetic variability. This is one of the first reports on the molecular epidemiology of hRSV strains from the Campinas metropolitan region, São Paulo state, Brazil. And is also the first description of the circulation pattern of hRSV genotypes in two university hospitals, revealing interesting differences between the two subgroups of the virus. J. Med. Virol. 80:1653–1660, 2008.

Presence of Vaccine-Derived Newcastle Disease Viruses in Wild Birds

Our study demonstrates the repeated isolation of vaccine-derived Newcastle disease viruses from different species of wild birds across four continents from 1997 through 2014. The data indicate that at least 17 species from ten avian orders occupying different habitats excrete vaccine-derived Newcastle disease viruses. The most frequently reported isolates were detected among individuals in the order Columbiformes (n = 23), followed in frequency by the order Anseriformes (n = 13). Samples were isolated from both free-ranging (n = 47) and wild birds kept in captivity (n = 7). The number of recovered vaccine-derived viruses corresponded with the most widely utilized vaccines, LaSota (n = 28) and Hitchner B1 (n = 19). Other detected vaccine-derived viruses resembled the PHY-LMV2 and V4 vaccines, with five and two cases, respectively. These results and the ubiquitous and synanthropic nature of wild pigeons highlight their potential role as indicator species for the presence of Newcastle disease virus of low virulence in the environment. The reverse spillover of live agents from domestic animals to wildlife as a result of the expansion of livestock industries employing massive amounts of live virus vaccines represent an underappreciated and poorly studied effect of human activity on wildlife.

Antiviral Activity of Bacillus sp. Isolated from the Marine Sponge Petromica citrina against Bovine Viral Diarrhea Virus, a Surrogate Model of the Hepatitis C Virus

The Hepatitis C virus causes chronic infections in humans, which can develop to liver cirrhosis and hepatocellular carcinoma. The Bovine viral diarrhea virus is used as a surrogate model for antiviral assays for the HCV. From marine invertebrates and microorganisms isolated from them, extracts were prepared for assessment of their possible antiviral activity. Of the 128 tested, 2 were considered active and 1 was considered promising. The best result was obtained from the extracts produced from the Bacillus sp. isolated from the sponge Petromica citrina. The extracts 555 (500 µg/mL, SI>18) and 584 (150 µg/mL, SI 27) showed a percentage of protection of 98% against BVDV, and the extract 616, 90% of protection. All of them showed activity during the viral adsorption. Thus, various substances are active on these studied organisms and may lead to the development of drugs which ensure an alternative therapy for the treatment of hepatitis C.

PREVALENCE OF NEWCASTLE DISEASE VIRUS IN BROILER CHICKENS (Gallus gallus) IN BRAZIL

This study was carried out during 2002/2003, aiming to determine the prevalence of virulent Newcastle disease virus strains (NDV) in Brazilian commercial poultry farms. Clinical samples were obtained from the Southeastern, Southern and Central-Western regions, which comprise the main area of the Brazilian poultry production. Serum samples and tracheal and cloacal swabs of 23,745 broiler chickens from 1,583 flocks, including both vaccinated chickens and those with no vaccination information, were tested for NDV using a diagnostic ELISA kit. The seropositivity was 39.1%, and the isolation percentage by flock varied from 1.0 to 7.6%, and by region from 6.5 to 58.4%. Higher isolation rates (74.3-83.3%) were obtained after three passages in embryonated chicken eggs. All isolates preliminarily identified as NDV were characterized as nonpathogenic strains, as their Intracerebral Pathogenicity Index (ICPI) was below 0.7. Based on results of this study, Brazil can claim a virulent NDV-free status for commercial flocks.

Variant isolates of human metapneumovirus subgroup B genotype 1 in Campinas, Brazil

BACKGROUND Human metapneumovirus (HMPV) is a paramyxovirus associated with respiratory illness. The genotypes of HMPV isolates in Brazil have not been well characterized. OBJECTIVES To investigate the presence of HMPV in clinical samples collected from pediatric patients of two university hospitals in the region of Campinas (São Paulo, Brazil) and to genotype them by partial sequencing of the HMPV F gene. STUDY DESIGN Nasopharyngeal aspirates were collected from children hospitalized between April and September, 2004 because of acute respiratory infections (ARI). RESULTS We identified HMPV in 8 of 142 (5.6%) clinical samples. We determined through phylogenetic analysis that HMPV isolates in Campinas during the study were clustered within subgroup B genotype 1. Two of the isolates analyzed showed significant differences from previously isolated B1 viruses, when compared to HMPV isolated in South Africa and Canada, and clustered in a separate branch within this genotype. CONCLUSIONS In 2004 in our geographic region all HMPV isolates from pediatric patients were in the B1 HMPV genetic group, with two variant isolates.