• JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
 
  Bookmark and Share
 
 
Master's Dissertation
DOI
10.11606/D.10.2016.tde-07102015-114224
Document
Author
Full name
Andressa Ferrari Arévalo
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 2015
Supervisor
Committee
Maiorka, Paulo César (President)
Cunha, Elenice Maria Sequetin
Mori, Claudia Madalena Cabrera
Title in Portuguese
Susceptibilidade de hamsters frente à infecção pelo herpesvirus equino tipo 1 causando encefalite e doença respiratória
Keywords in Portuguese
Hamster
Herpesvírus equino tipo 1
Infecção intranasal
Lavado broncoalveolar
Susceptibilidade ao EHV-1
Abstract in Portuguese
Este trabalho teve por objetivo avaliar as alterações respiratórias e neurológicas resultantes da infecção por via intranasal das diferentes estirpes nacionais do herpesvírus equino tipo 1 (EHV-1) em hamsters comparando sua susceptibilidade com estudos sobre infecção do EHV-1 em camundongos e equinos. Para isso, hamsters sírios machos, três semanas de idade, foram infectados por via intranasal com as estirpes do EHV-1 obtidas a partir de fetos abortados e potro neonato infectados (A4/72, A9/92, A3/97 e Iso/72). Os animais foram pesados e examinados diariamente em busca de sinais clínicos e neurológicos. Conforme os sintomas neurológicos apareceram, grupos de cinco hamsters foram eutanasiados por overdose de isoflurano na primeira etapa do projeto, e, de cetamina/xilazina por via intraperitoneal na segunda etapa. Na necropsia, sistema nervoso central (SNC), pulmão, fígado, baço e timo foram coletados para isolamento viral em cultura de células E-dermal e para análise histopatológica. Na segunda etapa do projeto, a lavagem broncoalveolar (LBA) com 3 ml de PBS por hamsters foi realizada para determinar a resposta inflamatória pulmonar através da contagem total e diferencial de leucócitos. Similar aos experimentos com camundongos, hamsters desafiados com as estirpes virais A4/72 e A9/92 apresentaram manifestações clínicas severas no terceiro dia pós-inoculação (dpi), tais como perda de peso aguda, dispnéia, desidratação, decúbito e morte. Observou-se também sinais neurológicos como hiperexcitabilidade, paralisia, espasmos, perda de propriocepção, andar em círculos e convulsões. Ao contrário dos camundongos, que não desenvolveram a doença; hamsters inoculados com as estirpes virais A3/97 e Iso/72 manifestaram sintomas respiratórios e neurológicos agudos entre quarto e quinto dpi, sendo as alterações respiratórias as mais evidentes, principalmente hemoptise e conjuntivite. O isolamento do vírus a partir do SNC foi positivo em todos os animais infectados; no entanto, todas as amostras de pulmões foram positivas apenas nos grupos infectado pelas estirpes virais A9/92 e A4/72. Todas as estirpes do EHV-1 foram isoladas a partir do baço, no entanto, a partir do timo foram isoladas apenas as estirpes A9/92 e A4/72, e, de fígado somente a estirpe viral Iso/72 não foi isolada. No LBA, a contagem total de leucócitos não demonstrou diferenças de valores significativas entre os grupos experimentais, sendo apenas evidente a presença de eritrócitos, macrófagos e neutrófilos na maioria dos esfregaços dos hamsters infectados. Porém, na contagem diferencial de leucócitos observou-se um aumento significativo de neutrófilo com consequente diminuição significativa de macrófagos nos hamsters infectados pelas estirpes virais A3/97, Iso/72 e A4/72 quando comparados ao grupo controle. Os hamsters infectados pela estirpe viral A9/92 mantiveram valores próximos aos do grupo controle. Ao avaliar microscopicamente o SNC, fígado e pulmão dos hamsters infectados foi observado infiltrado inflamatório, necrose e manguito perivascular em SNC; leucocitose e necrose no parênquima hepático com discreta pericolangite e proliferação de ducto biliar; e em pulmão observou inflamação, necrose, edema e hemorragia em bronquíolos e alvéolos. Concluindo, os resultados apontaram o hamster como a espécie mais susceptível à infecção pelo EHV-1 servindo como um modelo experimental complementar para estudos de doenças respiratória e neurológica provocadas por este agente em equinos
Title in English
Susceptibility of hamsters to equine herpesvirus type 1 infection causing encephalitis and respiratory disease
Keywords in English
Bronchoalveolar lavage
Equine herpesvirus type 1
Hamster
Intranasal route of infection
Susceptibility to EHV-1
Abstract in English
This study aimed to evaluate the respiratory and neurological disorders resulting from intranasal infection with different national strains of equine herpesvirus type 1 (EHV-1) in hamsters comparing their susceptibility to studies about EHV-1 infection in mice and horses. Therefore, male Syrian hamsters, three weeks of age, were infected via intransal with EHV-1 strains obtained from aborted fetuses and neonatal foal infected (A4/72, A9/92, A3/97 and Iso/72). The animals were weighed and examined daily for clinical search and neurological signs. As neurological symptoms appeared five hamsters groups were euthanized by isoflurane overdose in the first stage of the project, and ketamine/xylazine via intraperitoneal in the second stage. At necropsy, central nervous system (CNS), lung, liver, spleen and thymus were collected for virus isolation in E-dermal cell culture and histopathological analysis. In the second stage of the project, bronchoalveolar lavage (BAL) with 3 ml of PBS per hamsters was performed to determine the pulmonary inflammatory response through the total and differential leukocyte count. Similar to the experiments with mice, hamsters challenged with viral strains A4/72 and A9/92 had severe clinical manifestations in the third day post-inoculation (dpi), such as acute weight loss, dyspnea, dehydration, recumbency, and death. It was also observed neurological signs such as hyperexcitability, paralysis, spasms, loss of proprioception, circling and convulsions. Unlike mice, which did not develop disease; hamsters inoculated with viral strains A3/97 and Iso/72 showed acute respiratory and neurological symptoms between fourth and fifth dpi, and the most evident respiratory distress was hemoptysis and conjunctivitis. The virus isolation from CNS was positive in all infected animals; however, all lung samples were positive only in groups infected by A9/92 and A4/72 viral strains. All EHV-1 strains were recovered from spleen, however, only A9/92 and A4/72 viral strains were recovered from thymus, but only Iso/72 viral strain was not recovered from liver. BAL total leukocyte count showed no significant differences in values between the experimental groups but the presence of erythrocytes, macrophages and neutrophils were evident in most smears of infected hamsters. However, in the leukocyte differential count it was observed a significant increase in neutrophils with consequent significant reduction of macrophages in hamsters infected by viral strains A3/97, Iso/72 and A9/92 when compared with the control group. Hamsters infected with the A9/92 viral strain maintained values similar to the control group. When evaluating microscopically the CNS, liver and lungs of infected hamsters it was observed inflammatory infiltrate, necrosis and perivascular cuff in CNS; leukocytosis and necrosis in the liver parenchyma with discrete pericholangitis and bile duct proliferation; and inflammation, necrosis, edema and hemorrhage in the bronchioles and alveoli. Concluding, the results showed the hamster as the most susceptible species to EHV-1 infection serving as a complementary experimental model for studies of respiratory and neurological diseases caused by this agent in horses
 
WARNING - Viewing this document is conditioned on your acceptance of the following terms of use:
This document is only for private use for research and teaching activities. Reproduction for commercial use is forbidden. This rights cover the whole data about this document as well as its contents. Any uses or copies of this document in whole or in part must include the author's name.
Publishing Date
2016-04-15
 
WARNING: Learn what derived works are clicking here.
All rights of the thesis/dissertation are from the authors
CeTI-SC/STI
Digital Library of Theses and Dissertations of USP. Copyright © 2001-2021. All rights reserved.