Navegando por Autor "VASCONCELOS, Pedro Fernando da Costa"

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Acesso aberto (Open Access)
Environmental influences on antibody-enhanced dengue disease outcomes
(2012-12) DINIZ, Daniel Guerreiro; FÔRO, César Augusto Raiol; TURIEL, Maíra Catherine Pereira; SÓSTHENES, Márcia Consentino Kronka; DEMACHKI, Samia; GOMES, Giovanni Freitas; REGO, Carla M Damasceno; MAGALHÃES, Marina Cutrim; PINHO, Brunno Gomes; RAMOS, Juliana Pastana; CASSEB, Samir Mansour Moraes; BRITO, Maysa de Vasconcelos; SILVA, Eliana Vieira Pinto da; NUNES, Márcio Roberto Teixeira; DINIZ JUNIOR, José Antônio Picanço; CUNNINGHAM, Colm; PERRY, Victor Hugh; VASCONCELOS, Pedro Fernando da Costa; DINIZ, Cristovam Wanderley Picanço
Because an enriched environment (EE) enhances T-cell activity and T-lymphocytes contribute to immunopathogenesis during heterologous dengue virus (DENV) infections, we hypothesised that an EE increases dengue severity. To compare single serotype (SS) and antibody-enhanced disease (AED) infections regimens, serial intraperitoneal were performed with DENV3 (genotype III) infected brain homogenate or anti-DENV2 hyperimmune serum followed 24 h later by DENV3 (genotype III) infected brain homogenate. Compared AED for which significant differences were detected between the EE and impoverished environmental (IE) groups (Kaplan-Meyer log-rank test, p = 0.0025), no significant differences were detected between the SS experimental groups (Kaplan-Meyer log-rank test, p = 0.089). Survival curves from EE and IE animals infected with the AED regimen were extended after corticoid injection and this effect was greater in the EE than in the IE group (Kaplan-Meyer log-rank test, p = 0.0162). Under the AED regimen the EE group showed more intense clinical signs than the IE group. Dyspnoea, tremor, hunched posture, ruffled fur, immobility, pre-terminal paralysis, shock and death were associated with dominant T-lymphocytic hyperplasia and presence of viral antigens in the liver and lungs. We propose that the increased expansion of these memory T-cells and serotype cross-reactive antibodies facilitates the infection of these cells by DENV and that these events correlate with disease severity in an EE.
Acesso aberto (Open Access)
Persistence of experimental Rocio virus infection in the golden hamster (Mesocricetus auratus)
(2012-08) HENRIQUES, Daniele Freitas; QUARESMA, Juarez Antônio Simões; FUZII, Hellen Thais; NUNES, Márcio Roberto Teixeira; SILVA, Eliana Vieira Pinto da; CARVALHO, Valéria Lima; MARTINS, Lívia Carício; CASSEB, Samir Mansour Moraes; CHIANG, Jannifer Oliveira; VASCONCELOS, Pedro Fernando da Costa
Rocio virus (ROCV) is an encephalitic flavivirus endemic to Brazil. Experimental flavivirus infections have previously demonstrated a persistent infection and, in this study, we investigated the persistence of ROCV infection in golden hamsters (Mesocricetus auratus). The hamsters were infected intraperitoneally with 9.8 LD50/0.02 mL of ROCV and later anaesthetised and sacrificed at various time points over a 120-day period to collect of blood, urine and organ samples. The viral titres were quantified by real-time-polymerase chain reaction (qRT-PCR). The specimens were used to infect Vero cells and ROCV antigens in the cells were detected by immunefluorescence assay. The levels of antibodies were determined by the haemagglutination inhibition technique. A histopathological examination was performed on the tissues by staining with haematoxylin-eosin and detecting viral antigens by immunohistochemistry (IHC). ROCV induced a strong immune response and was pathogenic in hamsters through neuroinvasion. ROCV was recovered from Vero cells exposed to samples from the viscera, brain, blood, serum and urine and was detected by qRT-PCR in the brain, liver and blood for three months after infection. ROCV induced histopathological changes and the expression of viral antigens, which were detected by IHC in the liver, kidney, lung and brain up to four months after infection. These findings show that ROCV is pathogenic to golden hamsters and has the capacity to cause persistent infection in animals after intraperitoneal infection.
Acesso aberto (Open Access)
Prevalência de anticorpos contra arbovírus da família Bunyaviridae em búfalos de água
(Universidade Federal do Pará, 2015-09) CASSEB, Alexandre Rosário; SILVA, Sandro Patroca da; CASSEB, Livia Medeiros Neves; CHIANG, Jannifer Oliveira; MARTINS, Lívia Carício; VASCONCELOS, Pedro Fernando da Costa
The State of Pará comprises 26% of Brazilian Amazon region where a large diversity of arboviruses has been described. This study sought to assess the prevalence and distribution of haemagglutination-inhibition antibodies against antigens of nine different types of arbovirus of the Bunyaviridae family, where eight were Orthobunyavirus: Guaroa virus, Maguari virus, Tacaiuma virus, Utinga virus, Belem virus, Caraparu virus, Oropouche virus and Catu virus, and one Phlebovirus: Icoaraci virus in sera samples of water buffaloes in Pará State, Brazil. For all Arboviruses investigated there were antibodies, with the exception of Belem virus. Antibodies to Maguari viruswere more prevalent (7.33%). The water buffaloes of the present study showed variable levels of antibodies in monotypic and heterotypic reactions that may indicate there are movements from most bunyavirus studied in domestic buffaloes in the state of Pará, and the Maguari virus presents the largest circulation. Therefore, further studies are needed to investigate the role of water buffalo in the maintenance and dispersal of arboviruses, as well as whether these viruses can cause disease in that species, especially in cases of birth defects and abortions.
Acesso aberto (Open Access)
Virological and serological diagnosis of rabies in bats from an urban area in the brazilian Amazon
(Universidade Federal do Pará, 2015-12) OLIVEIRA, Rubens Souza de; COSTA, Lanna Jamile Corrêa da; ANDRADE, Fernanda Atanaena Gonçalves de; UIEDA, Wilson; MARTORELLI, Luzia Fatima Alves; KATAOKA, Ana Paula de Arruda Geraldes; ROSA, Elizabeth Salbé Travassos da; VASCONCELOS, Pedro Fernando da Costa; PEREIRA, Armando de Souza; FERNANDES, Marcus Emanuel Barroncas; CARMO, Antônio Ismael Barros do
The outbreaks of rabies in humans transmitted by Desmodus rotundus in 2004 and 2005, in the northeast of the Brazilian State of Para, eastern Amazon basin, made this a priority area for studies on this zoonosis. Given this, the present study provides data on this phenomenon in an urban context, in order to assess the possible circulation of the classic rabies virus (RABV) among bat species in Capanema, a town in the Amazon basin. Bats were collected, in 2011, with mist nets during the wet and dry seasons. Samples of brain tissue and blood were collected for virological and serological survey, respectively. None of the 153 brain tissue samples analyzed tested positive for RABV infection, but 50.34% (95% CI: 45.67-55.01%) of the serum samples analyzed were seropositive. Artibeus planirostris was the most common species, with a high percentage of seropositive individuals (52.46%, 95% CI: 52.31 52.60%). Statistically, equal proportions of seropositive results were obtained in the rainy and dry seasons (c2 = 0.057, d.f. = 1, p = 0.88). Significantly higher proportions of males (55.96%, 95% CI: 48.96-62.96%) and adults (52.37%, 95% CI: 47.35-57.39%) were seropositive. While none of the brain tissue samples tested positive for infection, the high proportion of seropositive specimens indicates that RABV may be widespread in this urban area.