Causative Agent Of Plaque

Poliomyelitis is caused by three types of polioviruses, designated 1, 2, and 3, which are distinguished by using antisera. These small, non-enveloped, single-stranded, positive sense RNA viruses are members of the enterovirus subgroup of the picor-navirus family. They can be grown in vitro in cell cultures, where they cause cell destruction. With low concentrations of virus, the areas of cell destruction, termed plaques, are separated from one another and are readily seen with the unaided eye (figure 26.16).

Figure 26.15 Individual with Atrophy of the Left Leg Due to Poliomyelitis

Poliovirus Plaques

8 mm

Figure 26.16 Plaques Produced by Poliomyelitis Virus in a Cell Culture Monolayer Each plaque represents an area of the monolayer that has been destroyed by replicating poliovirus.

8 mm

Figure 26.15 Individual with Atrophy of the Left Leg Due to Poliomyelitis

Figure 26.16 Plaques Produced by Poliomyelitis Virus in a Cell Culture Monolayer Each plaque represents an area of the monolayer that has been destroyed by replicating poliovirus.

Nester-Anderson-Roberts: I IV. Infectious Diseases I 26. Nervous System I I © The McGraw-Hill

Microbiology, A Human Infections Companies, 2003

Perspective, Fourth Edition

678 Chapter 26 Nervous System Infections

Table 26.6 Epidemic Viral Encephalitis

© Infected mosquito introduces encephalitis virus.

@ Virus multiplies locally, establishes brief low-level viremia.

@ Virus crosses blood-brain barrier and preferentially attacks the brain.

@ Destruction of brain tissue causes death or permanent disabilities such as emotional instability, mental retardation, paralysis of face, arm, leg.

© Due to brief viremia, there is no exit for the virus, thus humans are the final host.

Symptoms Abrupt onset, fever, headache, vomiting, disorientation, paralysis, seizures, deafness, coma Incubation period First symptoms within a few days;

encephalitic symptoms often within the first week

Causative agents Usually caused by one of four arboviruses, LaCrosse, St. Louis, western equine, or eastern equine Pathogenesis Replication of virus at the site of the mosquito bite, further replication in lymph nodes, then viremia that seeds brain tissue. Nerve cells in the brain invaded, destroyed. Process halted by neutralizing antibody Epidemiology Viruses transmitted to humans from birds or rodents by mosquitoes Prevention and Chicken sentinels to warn of arbovirus treatment epidemics. Insecticides and other anti mosquito preventive measures. No accepted treatment for arboviral encephalitis

How To Deal With Rosacea and Eczema

How To Deal With Rosacea and Eczema

Rosacea and Eczema are two skin conditions that are fairly commonly found throughout the world. Each of them is characterized by different features, and can be both discomfiting as well as result in undesirable appearance features. In a nutshell, theyre problems that many would want to deal with.

Get My Free Ebook


Responses

  • Kaylin
    What is the causative agent of plaque?
    12 months ago

Post a comment