Secondary replication Occurs in systemic infections when a virus reaches other tissues in which it is capable of replication, e. g. Poliovirus (gut epithelium -neurons in brain spinal cord)or Lentiviruses(macrophages-CNs many other tissues). If a virus can be prevented from reaching tissues where secondary replication can occur, generally no disease results
Secondary Replication • Occurs in systemic infections when a virus reaches other tissues in which it is capable of replication, e.g. Poliovirus (gut epithelium - neurons in brain & spinal cord) or Lentiviruses (macrophages - CNS + many other tissues). If a virus can be prevented from reaching tissues where secondary replication can occur, generally no disease results
Localized infections. Ⅴirus: Primary replication Rhinoviruses U.R.T Rotaviruses Intestinal epithelium Papillomavirus epidermis Systemic Infections Ⅴirus Primary replication Secondary Replication: Enteroviruses Intestinal epithelium Lymphoid tissue CN.S Herpesviruses Oropharynx or GUtract Lymphoid cells, C.N.S
: Localized Infections: Virus: Primary Replication: Rhinoviruses U.R.T. Rotaviruses Intestinal epithelium Papillomavirus es Epidermis Systemic Infections: Virus: Primary Replication: Secondary Replication: Enteroviruses Intestinal epithelium Lymphoid tissues, C.N.S. Herpesviruses Oropharynx or G.U.tract Lymphoid cells, C.N.S
Incubation periods of viral infections Influenza -2d Chickenpox 13-17d Common cold 1-3d Mumps 16-20d Bronchiolitis, croup 3-5d Rubella 7-20d Acute respiratory 5-7d Mononucleosis 30-50d disease Dengue 5-8d He epi atitis a 5-40d Herpes simplex 5-8d Hepatitis B 50-150d Enteroviruses 6-12d Rabies 30-100d poliomyelitis 5-20d Papilloma 50-150d Measles 9-12d HIV
Incubation periods of viral infections Influenza 1-2d Chickenpox 13-17d Common cold 1-3d Mumps 16-20d Bronchiolitis,croup 3-5d Rubella 17-20d Acute respiratory disease 5-7d Mononucleosis 30-50d Dengue 5-8d Hepatitis A 15-40d Herpes simplex 5-8d Hepatitis B 50-150d Enteroviruses 6-12d Rabies 30-100d poliomyelitis 5-20d Papilloma 50-150d Measles 9-12d HIV 1-10y
Types of Infection Inapparent infection( Subclinical infection) ° Apparent infection ● Acuteinfection Persistent nfection Chronic infections Latent Infection Slow virus infections
Types of Infection • Inapparent infection( Subclinical infection) . • Apparent infection: • Acute infection • Persistent Infection Chronic infections Latent Infection Slow virus infections
Chronic Infection Virus can be continuously detected mild or no clinical symptoms may be evident Chronic infection late disease HTLV-I leukemia Disease episode Shedding Chronic infection apatites Disease episode
Chronic Infection • Virus can be continuously detected ; mild or no clinical symptoms may be evident