polio

vector

this disease is only passed from person to person, but cockroaches and flies may serve as vectors for the subgroup enterovirus

vaccination

CDC recommends that children get four doses of polio vaccine. They should get one dose at each of the following ages: 2 months old 4 months old 6 through 18 months old 4 through 6 years old

reservoir

Humans are the only known reservoirs of poliovirus

mode of transmission

Most of the infections occur through the fecal-oral route, even though a small number of cases occur through the oral-oral route, though less common, through droplets from a sneeze or cough. An infected person may spread the virus to others immediately before and about 1 to 2 weeks after symptoms appear. The virus can live in an infected person's feces for many weeks. It can contaminate food and water in unsanitary conditions. People who don't have symptoms can still pass the virus to others and make them sick.

prevention

Polio vaccine protects children by preparing their bodies to fight the polio virus. Almost all children (99 children out of 100) who get all the recommended doses of vaccine will be protected from polio. There are two types of vaccine that can prevent polio: inactivated poliovirus vaccine (IPV) and oral poliovirus vaccine (OPV). Only IPV has been used in the United States since 2000; OPV is still used throughout much of the world.

control

Poliomyelitis can be prevented by the Salk-type (inactivated) and Sabin-type (live) attenuated poliovirus vaccines. Control may be achieved by public education on transmission modes and personal hygiene, proper sewage disposal, and supply of uncontaminated water supplies.

etiology

Poliomyelitis- Polio is caused by small RNA viruses. They are members of the enterovirus group of the Picornavirus family. still in Pakistan, Afghanistan, and Nigeria

gram stain

Poliovirus is neither gram-negative nor gram-positive because it is a virus and does not have a cell wall to stain.

virulence factor

Polioviruses attach to a plasma membrane protein, allowing the genome to be released into the cytoplasm. Local lymphoid tissues are targeted by the virus, allowing entry into the bloodstream. Central nervous system cells are then infected by the virus. "Replication of poliovirus in motor neurons of the anterior horn and brain stem results in cell destruction and causes the typical manifestations of poliomyelitis" . The neurological damage caused by the virus in the form of paralysis occurs when the nerve cells lyse from infestation of the virus.

disinfectants

Rubella virions are susceptible to ether, chloroform, sodium dodecyl sulphate (SDS), saponin, formaldehyde, ethylene oxide and beta- propiolactone. 1% sodium hypochlorite and 70% ethanol are also effective disinfectants

clinical signs and symptoms

Sore throat Fever Tiredness Nausea Headache Stomach pain These symptoms usually last 2 to 5 days then go away on their own. A smaller proportion of people with poliovirus infection will develop other more serious symptoms that affect the brain and spinal cord: Paresthesia (feeling of pins and needles in the legs) Meningitis (infection of the covering of the spinal cord and/or brain) occurs in about 1 out of 25 people with poliovirus infection Paralysis (can't move parts of the body) or weakness in the arms, legs, or both, occurs in about 1 out of 200 people with poliovirus infection

mortality

The death rate for polio varies from children to adults. In children, 2%-5% of all cases result in death, and in adults, 15%-30% of all cases result in death. The death rate increases to 25%-75%, when there is bulbar involvement

morphology

The poliovirus virion possesses icosahedral structure with 60 morphological units per virion, each unit consisting of four distinct viral proteins (VP1-VP4). VP1 faces outside and carries the major antigenic site for combination with serotype specific neutralizing antibodies.

treatment

There is no treatment that will cure polio. Early diagnosis and supportive treatments such as bed rest, pain control, good nutrition, and physical therapy to prevent deformities from occurring over time can help reduce the long-term symptoms due to muscle loss

diagnostic tests

Viral isolation is the recovery of poliovirus from the stool or throat of a person with poliomyelitis. Virus isolation from an acute flaccid paralysis case must be tested further, using oligonucleotide mapping (fingerprinting) or genomic sequencing. This secondary testing determines if the virus is "wild type" (causes polio disease) or vaccine type (could derive from a vaccine strain) (4). Serology is used to detect for antibodies during a suspected polio infection. Neutralizing antibodies appear early, in the disease, and may reach high levels by the time the infected patient is hospitalized. This means, a fourfold rise in antibody titer may not be demonstrated (4). Poliovirus isolation from the cerebrospinal fluid (CSF) rarely accomplished, but serves as a diagnostic tool. In a poliovirus infection, the CSF generally contains a significantly elevated number of white blood cells (10-200 cells/mm3, primarily lymphocytes) and a mildly elevated protein (40-50 mg/100 mL) (4)

morbidity

Wild poliovirus cases have decreased by over 99% since 1988, from an estimated 350 000 cases in more than 125 endemic countries then, to 22 reported cases in 2017.