micro exam #3 poliomyelitis (polio) document

advantages of sabin over salk vaccine

ease of administration on a sugar cube or in a sugary liquid longer lasting immunity (salk did not produce immunity in all recipients) reduced the fecal oral transmission route through the GI tract

diagnosis for polio

isolation and culturing of virus from pharynx and feces immunological testing of blood serum for antibiotics

factors which increase the severity of the disease include (polio)

malnutrition, physical exhaustion, corticosteroids, radiation, pregnancy, immune deficiency, removal of tonsils

symptoms for polio

most infected people (90%) have no symptoms or very mild symptoms and usually go unrecognized initial symptoms: fever, fatigue, headache, vomiting, stiffness in the neck, and pain in the limbs key symptoms: paralysis, without losing the sensation

prevention for polio

no cure best protection is prevention for as little as $0.60 worth of vaccine a child can be protected against this disease for life

types of polio

non paralytic: no symptoms or mild "flu like" symptoms spinal paralytic: can lead to leg paralysis bulbar: could result in a victim spending the rest of his life in an "iron lung" although most poliovirus infections are unapparent or mild and non paralytic the virus reached the CNS in 1-2% of the cases high fever, back pain, and muscle spasms result in less than 1% of cases, the symptoms are accompanied by partial or complete paralysis of muscles in a relaxed state the nature and degree of paralysis depends on: which neurons in the spinal cord and brain are infected, how severely the neurons are damaged, and if the neurons are lyzed the very young and very old are likely to suffer paralysis as a result of polio virus infection

incidence and eradication efforts for polio

polio cases have decreased by over 99% since 1988, from an estimated 350,000 cases then, to 650 reported cases in 2011. the reduction is the result of the global effort to eradicate polio. type 2 has been reported eradicated and type 3 case numbers are down to lowest ever levels in 2010 only 4 countries remain polio endemic, down from more than 125 in 1988: Afghanistan, India(polio stopped in Jan. 2011), Nigeria, and Pakistan , Seria pockets of transmission in these areas are the current focus of the polio eradication initiative. 1988: global polio eradication initiative began: spearheaded by national governments, WHO, rotary international, CDC, UNICEF, and supported by many partners, including the Bill and Melinda Gates foundation as long as a single child remains infected children in all countries are at risk of contracting polio failure to eradicate polio from these last remaining strongholds could result in as many as 200,000 new cases every year, within 10 years all over the world

causal agent for poliomyelitis (polio)

polio virus there are 3 serotypes of the virus. these serotypes have a strong affinity for the motor neurons of the spinal cord and brain it has been reported that type 2 was eradicated in 2000

combination polio vaccines (1995)

recommended to reduce the incidence of vaccine related polio reschedule for combination vaccine: infants: shots of inactivated vaccine at 2 and 4 months; toddlers: oral doses of the attenuated vaccine at 6 months and up to 18 months older children: 4-6 years of age the oral vaccine is needed b/c it is effective against "wild" polio virus that, although eradicated from U.S. could be brought in from other areas by travelers or immigrants before salk vaccine in 1955 only non specific public health measures were available to prevent the spread of polio schools, swimming pools, and other places where crowds (especially children) gathered were closed application of large amounts of insecticides, b/c it was incorrectly believed that insects played a role in transmission of this disease b/c insufficient vaccine was available early on clinic were set up to immunize pregnant women and young children

transmission for polio

spread through person to person contact by saliva or other body fluids, fecal oral route, by food, water, and hands contaminated with infected feces when a child is infected with wild polio virus, the virus enters the body through the mouth, invades the throat and digestive system where it multiplies in the intestines. it eventually spreads throughout the immune system through the bloodstream it is then shed into the environment through the feces where it can spread rapidly through the community, especially in situations of poor hygiene and sanitation if a sufficient number of children are fully immunized against polio, the virus is unable to find susceptible children to infect and it dies out

incubation period for polio

usually 6-20 days but symptoms can be noticed as early as 3 days to as late as 35 days after contracting the virus

people most at risk for polio

children under 5 years of age but adults can also contract

NOTE:

90% of the cases, mostly in children, recover within a few weeks. polio strikes adults more severely (ex. Franklin D Roosevelt was afflicted with polio as an adult and had to wear braces and use a wheelchair for the remainder of his life) 1 in 200 infections leads to irreversible paralysis, usually in the legs. the virus destroys the neurons that activate the muscle, so the limbs become "floppy". this is referred to as "AFP (acute Flaccid Paralysis) with bulbar polio there is more extensive paralysis, involving the trunk and muscles of the thorax and abdomen. this can result in the person becoming a quadriplegic also with the most severe cases (bulbar polio) the virus attacks the nerve cells of the brain stem, reducing breathing capacity and causing difficulty in swallowing and speaking. among those paralyzed 5-10% die when their breathing muscles become immobilized (iron lung patients)

salk vaccine (1955)

IPV (series of intramuscular injections usually inactivated virus) about 70-90% effective

sabin vaccine (1963)

OPV (oral dose containing attenuated virus) almost 100% effective

post polio syndrome

a condition in which people who survived polio, years before, suffer waking of paralysis of muscles (crutches and braces again needed) not a recurrence of the disease and is not contagious in this form believed to be due to the overuse of compensating muscles that have been overused for too many years and can no longer function properly

poliomyelitis (polio)

a crippling and potentially fatal, highly contagious disease an ancient disease (Egyptian wall paintings) as well as a dreaded disease in the early 1950s (1952 peak year) parents feared coming of summer, as well as the diagnosis of a case of paralytic polio