Infectious diseases : Poliomyelitis

Confirmed Poliomyelitis areas in the world - 1999/2000

Poliomyelitis (polio) or infantile paralysis is a highly infectious disease caused by a virus that can cause paralysis in a matter of hours. Human beings are the reservoir of this disease and the transmission mechanism is mainly through person to person contact, through feces to mouth, or mouth to mouth, contact. The virus enters the organism through the mouth and multiplies in the intestine. The incubation period of the disease is usually from seven to twelve days, but can vary from two to thirty days. Initial symptoms are fever, tiredness, headaches, vomiting, rigidity in the back of the neck and pain in the arms and legs. The disease is most prevalent among younger children, under five years old. No cure is available and vaccine application is the best means of prevention.

Polio is one of the diseases that can be eradicated of the world because it affects human beings exclusively (it does not have an animal source or reservoir). An effective vaccine exists, which produces life-long immunity and the virus survives in the environment only for a short period.

The last case of polio registered in Brazil was in 1989, after various countrywide vaccination campaigns. By 1994, the wild poliovirus was considered to have been eradicated in the country. However, circulation of the virus continues to affect other countries, which means that continued and permanent surveillance is fundamental here in order to avoid the reintroduction of the virus into Brazil. This necessarily involves a high level of vaccination coverage and active surveillance of acute flaccid paralyses (AFP), characterized by a decrease in muscle tone.

The vaccine adopted in Brazil is tri-active: it consists of three poliovirus types (1, 2 and 3). It is easy to administer, is well accepted by patients and is relatively efficient. The possibility of post-vaccine reaction is rare.
Children with congenital or acquired immunologic deficiency , children that are in contact at home with an immunodeficient person and those requiring anti-polio vaccine and bone marrow transplants, must receive the deactivated vaccine (in injectable form) against poliomyelitis.

Measures should be taken in respect of travelers in order to restrict the circulation and transmission of the wild poliovirus:

1.The following measures must apply to people arriving in Brazil from areas where wild poliovirus is circulating:

• Adults and children, regardless of previous immunization history, must receive a dose of oral vaccine against poliomyelitis immediately upon arrival.
  
• People under 15 years old must complete the basic anti-polio vaccination schedule in accordance with the record of previously received doses as detailed in the relevant certificates, regardless of the situation in the countries that issued the certificates.
  

2. The measures below apply to people travelling to countries where the wild poliovirus is in circulation:

• Adults and children, regardless of their age and of their immunization record, they should receive the dose of oral vaccine before the trip.
  
• People who do not possess a full vaccination certificate or do not carry complete proof of their immunization record must bring their certificates up to date by obtaining vaccination in the destination country as soon as possible after arrival.

Point to note: All the vaccination places in ports, airports and border crossing facilities should be supplied with the oral vaccine against poliomyelitis.

Using the recommendations of the Brazilian National Epidemiology Centre as a basis, the measures must also be applied to the drivers and crews of ships, aircraft and land vehicles arriving in Brazilian territory from countries where the wild poliovirus is known to be in circulation (see table in annex).

Confirmed areas of poliomyelitis by country and region (1999/2000).