The poliomyelitis is an acute infection produced by the polio virus that affects the human central nervous system. It is transmitted by fecal-oral and respiratory contact.There are two types of vaccine, OPV （live att...The poliomyelitis is an acute infection produced by the polio virus that affects the human central nervous system. It is transmitted by fecal-oral and respiratory contact.There are two types of vaccine, OPV （live attenuated virus） and IPV （inactivated polio virus）. Currently, there is a plan of vaccination until the age of 5 with OPV. The children vaccinated expel a virus （derived from the vaccine） to the environment, and some of the people that have oral contact with them, get vaccinated by the herd behavior. Nevertheless, taking into account the lately observed facts about the reversion to virulence of the oral polio vaccine during its circulation in the environment, a change in the current vaccination schedule is being contemplated, where the oral polio vaccine can be replaced by the inactivated vaccine. Nowadays, In Colombia the inactivated oral polio vaccine is recommended for children presenting immune deficiency who are vaccinated with IPV. These children do not expel poliovirus to the environment. This work presents a mathematical model that describes the dynamics of the infection in a population where the two types of vaccination are carried out. The population is divided into two groups of age and Michaelis-Menten interactions. Different strategies of vaccination are simulated and analyzed.展开更多
Eight strains of nervous necrosis virus （NNV） isolated in Vietnam were used to detect the pathogenicity and immune response in sea bass （SB）. All strains induced cytopathic effect in SB cell line, complete destruc...Eight strains of nervous necrosis virus （NNV） isolated in Vietnam were used to detect the pathogenicity and immune response in sea bass （SB）. All strains induced cytopathic effect in SB cell line, complete destruction of monolayer of cells appeared after seven days post infection （dpi）. Virus titer was different for each strain, TCIDso ranged from 102.7 to 1069, and LDs0 from 1015 to 1075. Five NNV strains named QN 02, QN 05, QN 07, ND 11 and KH 05 had higher virulence than the other three, the first causing 100% mortality in experimental fish 3-5 dpi. NNV KH 05 had the highest antigenic similarity, and it was inactivated completely by 0.2% formalin, 0.002 mol/L binary ethylenimine （BEI） and 0.1% beta-propiolactone. The neutralization antibody titer obtained in fish of groups immunized by BEI 0.002 M and beta-propiolactone 0.1% inactivated virus was four to eight times higher than that of the group treated with the formalin inactivated virus. The antibody titer in fish immunized with beta-propiolactone inactivated virus was more persistent. The efficacy of vaccines developed from beta-propiolactone inactivated virus and aluminium hydroxide （AH） or aluminum phosphate （AP） was observed by intramuscularly immunizing Epinephelusfuscoguttatus size 1.5 cm. Neutralizing antibodies appeared in vaccinated fish on 10th day post-immunization （dpi） at a dilution of 1：16; 1：32 and highest levels were reached on 30-45 dpi, at dilutions of 1：256 and 1：512, after treatment with AH and AP vaccine, respectively. The relative percent of survival （RPS） of vaccine at 30 dpi was highest with challenge doses 0.2-1 × 10^6.8 TCIDs0, the RPS varied from 80%-83.3% in both groups of AH and AP immunization. This result provides the basis for developing a vaccine against NNA disease.展开更多
文摘The poliomyelitis is an acute infection produced by the polio virus that affects the human central nervous system. It is transmitted by fecal-oral and respiratory contact.There are two types of vaccine, OPV （live attenuated virus） and IPV （inactivated polio virus）. Currently, there is a plan of vaccination until the age of 5 with OPV. The children vaccinated expel a virus （derived from the vaccine） to the environment, and some of the people that have oral contact with them, get vaccinated by the herd behavior. Nevertheless, taking into account the lately observed facts about the reversion to virulence of the oral polio vaccine during its circulation in the environment, a change in the current vaccination schedule is being contemplated, where the oral polio vaccine can be replaced by the inactivated vaccine. Nowadays, In Colombia the inactivated oral polio vaccine is recommended for children presenting immune deficiency who are vaccinated with IPV. These children do not expel poliovirus to the environment. This work presents a mathematical model that describes the dynamics of the infection in a population where the two types of vaccination are carried out. The population is divided into two groups of age and Michaelis-Menten interactions. Different strategies of vaccination are simulated and analyzed.
文摘Eight strains of nervous necrosis virus （NNV） isolated in Vietnam were used to detect the pathogenicity and immune response in sea bass （SB）. All strains induced cytopathic effect in SB cell line, complete destruction of monolayer of cells appeared after seven days post infection （dpi）. Virus titer was different for each strain, TCIDso ranged from 102.7 to 1069, and LDs0 from 1015 to 1075. Five NNV strains named QN 02, QN 05, QN 07, ND 11 and KH 05 had higher virulence than the other three, the first causing 100% mortality in experimental fish 3-5 dpi. NNV KH 05 had the highest antigenic similarity, and it was inactivated completely by 0.2% formalin, 0.002 mol/L binary ethylenimine （BEI） and 0.1% beta-propiolactone. The neutralization antibody titer obtained in fish of groups immunized by BEI 0.002 M and beta-propiolactone 0.1% inactivated virus was four to eight times higher than that of the group treated with the formalin inactivated virus. The antibody titer in fish immunized with beta-propiolactone inactivated virus was more persistent. The efficacy of vaccines developed from beta-propiolactone inactivated virus and aluminium hydroxide （AH） or aluminum phosphate （AP） was observed by intramuscularly immunizing Epinephelusfuscoguttatus size 1.5 cm. Neutralizing antibodies appeared in vaccinated fish on 10th day post-immunization （dpi） at a dilution of 1：16; 1：32 and highest levels were reached on 30-45 dpi, at dilutions of 1：256 and 1：512, after treatment with AH and AP vaccine, respectively. The relative percent of survival （RPS） of vaccine at 30 dpi was highest with challenge doses 0.2-1 × 10^6.8 TCIDs0, the RPS varied from 80%-83.3% in both groups of AH and AP immunization. This result provides the basis for developing a vaccine against NNA disease.
