Atividade de três drogas antivirais sobre os herpesvírus bovino tipos 1, 2 e 5 em cultivo celular

A atividade de três fármacos antivirais (Aciclovir [ACV], Ganciclovir [GCV] e Foscarnet [PFA]) foi testada in vitro frente aos herpesvírus bovino tipos 1 (BoHV-1), 2 (BoHV-2) e 5 (BoHV-5). Para isso, utilizou-se o teste de reducao de placas virais em cultivo celular, testando-se diferentes concentracoes dos farmacos frente a 100 doses infectantes para 50% dos cultivos celulares (DICC50) dos respectivos virus. Pelo teste de MTT (3-(4,5-Dimethylthiazol- 2-yl)-2,5-diphenyltetrazolium bromide), verificou-se que concentracoes inferiores a 200ƒÊg/mL dos tres antivirais resultaram em indices de viabilidade de celulas MDBK e Hep2 superiores a 80%. Com base na concentracao citotoxica para 50% das celulas (CC50) e na concentracao dos farmacos efetiva para inibir em 50% o numero de placas virais (EC50), calculou-se o indice de seletividade (IS) dos antivirais para os tres herpesvirus. Assim, o ACV demonstrou ser moderadamente ativo frente ao BoHV-1 (EC50: 112,9ƒÊg/mL e IS: 4,5), ao BoHV-2 (EC50: 114,2 ƒÊg/mL e IS: 4,5) e BoHV-5 (EC50: 96,9ƒÊg/mL e IS: 5,3). O GCV apresentou atividade moderada frente ao BoHV-2 (EC50: 33,5ƒÊg/mL e IS: 16,6) e, em menor grau, contra o BoHV-5 (EC50: 123,2ƒÊg/mL e IS: 4,5), sendo ineficaz frente ao BoHV-1 (EC50: 335,8ƒÊg/mL e IS: 1,7). O PFA apresentou atividade antiviral mais pronunciada, sendo o unico farmaco que, na concentracao de 100ƒÊg/mL, inibiu completamente a producao de placas pelos tres virus testados. O PFA foi o mais efetivo in vitro frente ao BoHV-1 (EC50: 29,5ƒÊg/mL e IS: 42,2), ao BoHV-2 (EC50: 45,2ƒÊg/mL e IS: 27,6) e ao BoHV-5 (EC50: 7,8ƒÊg/mL e IS: 160,6). Portanto, os resultados obtidos indicam que o PFA pode se constituir em um candidato para terapia experimental de infeccoes pelos herpesvirus de bovinos in vivo.The activity of three anti-herpetic drugs (Acyclovir [ACV], Gancyclovir [GCV] and Foscarnet [PFA]) was tested against bovine herpesvirus 1 (BoHV-1), 2 (BoHV-2) and 5 (BoHV-5) in vitro using the plaque reduction assay. Different drug concentrations were tested against one hundred 50% tissue culture infectious dose (TCID50) of the respective viruses. Drug concentrations lower than 200μg/mL resulted in viability rates of more than 80% for MDBK and Hep2 cells in the MTT test (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide). The selectivity index (IS) of the drugs was calculated dividing the concentration of the drug that is cytotoxic for 50% of the cells (CC50) by the concentration of the drug that was effective in reducing by 50% the number of viral plaques (EC50) for the three herpesviruses. Thus, ACV was shown to be moderately active against BoHV-1 (EC50: 112.9μg/mL; IS: 4.5), BoHV-2 (EC50: 114.2μg/mL; IS: 4.5) and BoHV-5 (EC50: 96.9μg/mL; IS: 5.3). GCV was effective against BoHV-2 (EC50: 33.5μg/mL; IS: 16.6), moderately effective against BoHV-5 (EC50: 123.2μg/mL; IS: 4.5) and poorly active against BoHV-1 (EC50: 335.8μg/mL; IS: 1.7). PFA exhibited the highest antiviral activity, being the only drug that, at concentration of 100μg/mL, completely inhibited plaque formation by all three viruses. PFA was the most effective in vitro against BoHV-1 (EC50: 29.5μg/mL; IS: 42.2), BoHV-2 (EC50: 45.2μg/mL; IS: 27.6) and BoHV-5 (EC50: 7.8μg/mL; IS: 160.6). Thus, the results indicate that PFA is a promising candidate for experimental therapeutic testing in vivo against bovine herpesviruses

Susceptibility of the dromedary (Camelus dromedarius) to rotavirus infection

Camelus dromedarius) is susceptible to rotavirus infection. Among 55 dromedary sera collected in Morocco, 27, it is to say about half of them, possessed anti-rotavirus antibodies. The dromedary is the refore susceptible to rotavirus infection, like many other animal species.Camelus dromedarius) est réceptif à l’infection par rotavirus. Sur 55 sérums de chamelons récoltés au Maroc, 27, soit la moitié à peu près, contenaient des anticorps dirigés contre ce virus. Le dromadaire est réceptif a l’infection par le rotavirus, comme la plupart des autres espèces animales