[Poliomyelitis--why we must continue to vaccinate!]

The eradication of polio--that is the worldwide elimination of the wild poliovirus--is now within reach. The current success of this international project is due largely to the rigorous immunization of the general population. Both live oral polio vaccine (OPV) and inactivated vaccine (IPV) administered by injection are applied, the pros and cons of each having to be weighed up. Since 1998, only the dead IPV vaccine has been recommended in Germany. It is essential that the acceptance of the need for immunization should not decline, and that the inoculation rate in countries in which polio has apparently been eliminated, should not fall below the critical threshold of about 85-80%. If in the future this figure is not reached, the population would be put at risk by the re-introduction of the polio virus into the country. Even when global elimination has been achieved, vaccination must be continued for several years. The recommended immunization schedule covers three vaccinations for basic immunization plus a booster vaccination in adolescence.

Acute flaccid paralysis surveillance systems for expansion to other diseases, 2003-2004

Since the 1988 World Health Assembly resolution to eradicate poliomyelitis, the number of countries where polio is endemic has decreased from 125 in 1988 to six at the end of 2003. As part of the eradication strategy, a global surveillance system was established to 1) identify acute flaccid paralysis (AFP) cases in children aged < or =15 years and 2) deploy a network of accredited laboratories to perform virologic testing of stool specimens to determine whether the paralysis resulted from poliovirus infection. As AFP surveillance systems matured, countries increasingly applied AFP surveillance strategies and infrastructure to detect other diseases. This report describes the status of global AFP surveillance, including its expansion or use as a model in 131 (66%) of 198 countries for the reporting of measles and other vaccine-preventable diseases. As poliomyelitis is eradicated, AFP surveillance systems in these and other countries might be further expanded and adapted to improve the detection of and response to other diseases.

Laboratory surveillance for wild and vaccine-derived polioviruses, January 2003-June 2004

In 1988, the World Health Assembly resolved to eradicate poliomyelitis globally by 2000. Progress toward achieving this goal has been reported from countries where polio is endemic, and three World Health Organization (WHO) regions (Americas, Europe, and Western Pacific) appear to be free of indigenous wild poliovirus (WPV) transmission. One key strategy for eradicating polio is establishing sensitive polio surveillance systems by investigating acute flaccid paralysis (AFP) cases. To ensure that specimens from persons with AFP undergo appropriate processing for viral isolation, WHO established a global polio laboratory network in 1988. This report updates previous publications, summarizes the laboratory network's performance, and describes the location and characterization of WPV and vaccine-derived poliovirus (VDPV) during January 2003-June 2004.

Notification of patients with acute flaccid paralysis since certification of Australia as polio-free

OBJECTIVE

Surveillance of patients presenting with acute flaccid paralysis (AFP) is the World Health Organization (WHO) recommended method for the detection of incident cases of poliovirus infection. Australia was certified free of circulating poliovirus in 2000 but is required to continue AFP surveillance until global certification. Although Australia reached the WHO nominated surveillance target in 2000 and 2001, it was not reached in 2002. Notification rates between states have been variable. We aim to investigate the difference in notification rates by state to determine whether different rates reflect different patterns of disease or different approaches to reporting.

METHODS

Notification rates were reviewed by state for the years 1997-2002. The completeness of case ascertainment was reviewed from published studies. Key informants described differences in AFP reporting in states with consistent differences in notification rates.

RESULTS

Australia achieved 75% of the WHO surveillance target for AFP cases between 1997 and 1999 and 98% between 2000 and 2002. After 2000, Queensland achieved 150% of its target while Victoria achieved less than 50%. New South Wales reached its target over the entire 6 years but other states and territories were not as consistent. Although the formal process for AFP reporting is uniform throughout Australia, many differences in approach were identified between Victoria and Queensland.

CONCLUSION

Maintaining AFP surveillance at the required WHO standard will be more likely in Australia if the populous states are able to notify cases at the same rate as Queensland (since 2000) and New South Wales (in general).

Progress toward poliomyelitis eradication--Afghanistan and Pakistan, January 2003-May 2004

Since the 1988 World Health Assembly resolution to eradicate poliomyelitis, the number of countries where polio is endemic decreased from approximately 125 to six by the end of 2003. In 2003, poliovirus importations were reported in 10 countries, including eight in West and Central Africa, one in Southern Africa (Botswana), and one in the Middle East (Lebanon). Two countries where poliovirus remains endemic are Afghanistan and Pakistan, which are analyzed together because of their geographic proximity, frequent cross-border population movements, and genetically similar wild poliovirus (WPV) lineages. This report describes intensified polio eradication activities in Afghanistan and Pakistan during January 2003-May 2004, summarizes progress made toward eradication, and highlights the remaining challenges to interrupting poliovirus transmission.

Wild poliovirus importations--West and Central Africa, January 2003-March 2004

Since the 1988 World Health Assembly resolution to eradicate poliomyelitis, three World Health Organization (WHO) regions (Americas, European, and Western Pacific) have been certified polio-free, and the number of countries with endemic polio has decreased from 125 in 1988 to six in 2003 (Afghanistan, Egypt, India, Niger, Nigeria, and Pakistan). During January 2003-March 2004, importations of wild poliovirus (WPV) occurred in eight countries that were previously polio-free: five in the West African block (Benin, Burkina Faso, Cote d'Ivoire, Ghana, and Togo) and three in the Central African block (Cameroon, Central African Republic, and Chad), resulting in 63 polio cases. This report summarizes the 1) investigation and response to these WPV importations and 2) progress toward polio eradication in West and Central Africa.

Search for poliovirus carriers among people with primary immune deficiency diseases in the United States, Mexico, Brazil, and the United Kingdom

OBJECTIVE

To estimate the rate of long-term poliovirus excretors in people known to have B-cell immune deficiency disorders.

METHODS

An active search for chronic excretors was conducted among 306 persons known to have immunoglobulin G (IgG) deficiency in the United States, Mexico, Brazil, and the United Kingdom, and 40 people with IgA deficiency in the United States. Written informed consent or assent was obtained from the participants or their legal guardians, and the studies were formally approved. Stool samples were collected from participants and cultured for polioviruses. Calculation of the confidence interval for the proportion of participants with persistent poliovirus excretion was based on the binomial distribution.

FINDINGS

No individuals with long-term excretion of polioviruses were identified. Most participants had received oral poliovirus vaccine (OPV) and almost all had been exposed to household contacts who had received OPV. Polioviruses of recent vaccine origin were transiently found in four individuals in Mexico and Brazil, where OPV is recommended for all children.

CONCLUSION

Although chronic poliovirus excretion can occur in immunodeficient persons, it appears to be rare.

Laboratory surveillance for wild and vaccine-derived polioviruses, January 2002-June 2003

After the 1988 World Health Assembly resolution to eradicate poliomyelitis, the Global Laboratory Network for Poliomyelitis Eradication (the laboratory network) was established by the World Health Organization (WHO). The laboratory network is one component of an international surveillance system for detecting polioviruses through laboratory investigation of stool samples from persons with acute flaccid paralysis (AFP). This infrastructure is critical for guiding strategies to eradicate polio globally. This report summarizes the laboratory network's performance and describes the location and characterization of wild poliovirus (WPV) and vaccine-derived poliovirus (VDPV) during January 2002-June 2003. The achievement and maintenance of polio eradication globally requires the continued support of national governments and partner agencies.

Progress toward poliomyelitis eradication--Afghanistan and Pakistan, January 2002-May 2003

Since 1988, when the World Health Assembly resolved to eradicate poliomyelitis worldwide, the number of countries in which polio is endemic has decreased from 127 to seven, including Afghanistan and Pakistan. These two countries are considered one epidemiologic block because of their geographic proximity, frequent cross-border population movement, and the presence of genetically similar wild poliovirus (WPV) lineages. Although polio remains endemic in both countries, progress in interrupting poliovirus transmission has been substantial. This report describes intensified polio eradication activities in Afghanistan and Pakistan during January 2002-May 2003, summarizes progress made, and highlights the remaining challenges to interrupting poliovirus transmission.

West Nile virus infection: a new acute paralytic illness

OBJECTIVE

To determine the clinical, laboratory, electrodiagnostic, radiologic, and pathologic characteristics that define the spectrum of CNS disease caused by West Nile virus (WNV) infection.

METHODS

The records of all patients hospitalized at the Cleveland Clinic from August 2002 to September 2002 with WNV infection were reviewed.

RESULTS

Of 23 cases, the median age was 74 years old, and 74% were men. Symptoms included fever (100%), altered mental status (74%), gastrointestinal complaints (43%), back pain (35%), and rash (26%). In half, meningitis or encephalitis overlapped with flaccid weakness that progressed over 3 to 8 days, with a tendency to be proximal and asymmetric. Laboratory abnormalities included hyponatremia (30%) and initial CSF neutrophilic pleocytosis. Electrodiagnostic studies in two patients showed reduced motor amplitudes with normal conduction velocities and active denervation. In two other patients, reduced sensory amplitudes were also seen. MRI changes included cauda equina enhancement and parenchymal spinal cord signal abnormalities and parenchymal or leptomeningeal signal changes in the brain. Autopsy in three cases showed chronic perivascular inflammation in the brain and inflammatory changes with anterior horn cell loss in the spinal cord.

CONCLUSION

An overlapping spectrum of meningitis, encephalitis, and myeloradiculitis occurs in CNS WNV infection. Fever, rash, abdominal and back pain, preceding a proximal, asymmetric flaccid weakness, with CSF pleocytosis help distinguish the motor syndrome from Guillain-Barré syndrome. Pathologic changes in the CNS resembled poliomyelitis.

Progress toward poliomyelitis eradication--Nigeria, January 2002--March 2003

Since 1988, when the World Health Assembly resolved to eradicate poliomyelitis globally, the annual estimated incidence of polio has decreased >99%. Nigeria is the most populous country in Africa (estimated 2000 population: 127 million) and a major poliovirus reservoir. This report summarizes progress toward polio eradication in Nigeria during January 2002--March 2003, highlighting progress in acute flaccid paralysis (AFP) surveillance and evidence of wild poliovirus (WPV) circulation in areas of lower vaccination coverage. The findings underscore the importance of achieving high-quality supplementary immunization activities (SIAs).

Progress toward poliomyelitis eradication--Southern Africa, 2001-March 2003

Since the 1988 World Health Assembly resolution to eradicate poliomyelitis globally, substantial progress has been made in all World Health Organization (WHO) regions, and three regions (Americas, European, and Western Pacific) are classified as polio-free. The African Region comprises four epidemiologic blocks (Central, Eastern, Southern, and Western). The Southern African block comprises 14 countries--10 on the mainland (Angola, Botswana, Lesotho, Malawi, Mozambique, Namibia, South Africa, Swaziland, Zambia, and Zimbabwe) and four in the Indian Ocean (Comoros, Madagascar, Mauritius, and Seychelles)--with a combined total population in 2002 of approximately 120 million persons. This report summarizes polio eradication efforts in the Southern African block during January 2001-March 2003, which indicate the possible interruption of wild poliovirus (WPV) transmission and underscore the need to sustain polio eradication efforts.

Paralytic poliomyelitis caused by a vaccine-derived polio virus in an antibody-deficient Argentinean child

We describe a case of poliomyelitis in a 3-year-old Argentinean boy with X-linked hypogammaglobulinemia. The child had no history of polio vaccination, but a poliovirus isolated from a stool sample had 97.2% genetic similarity to the Sabin 1 vaccine strain. According to the WHO definition, this is the first case reported of a vaccine-derived poliovirus infection recorded in continental Latin America.

Diagnosis of acute flaccid paralysis: injection injury or polio?

In many countries, the treatment of choice for all fevers is one or more injections. These injections are associated with a risk of nerve damage. If cases of poliomyelitis are not to be missed, the diagnosis of injection trauma or traumatic neuritis (TN) must be exact. The guides for distinguishing between TN and polio are not clear. It is probable that some cases of polio are misdiagnosed as TN. As three-quarters of children with paralytic polio receive injections just before the onset of paralysis, their paralysis may be mistaken for TN. Clearer guidelines are proposed, together with suggestions for better documentation of muscles injected and paralysed. All cases of reported TN should be monitored and new diagnostic guidelines published. To protect their children, mothers must be educated to understand that injections for fever can cause harm. This must be an important part of the eradication programme for poliomyelitis.

Amyotrophic lateral sclerosis and other motor neuron diseases

The anterior horn cell diseases, with the exception of polio, are progressive degenerative diseases of the motor neurons. These disorders include SMA types I to III in children and familial and sporadic ALS and its variants (PMA, PLS, and PBP), Kennedy's disease, and SMA type IV in adults. The electrodiagnostic study is a crucial step in the diagnostic process for all of these disorders. In general, motor NCS may be normal or reveal low CMAP amplitudes with relatively normal conduction velocities. Sensory NCS, except in the case of Kennedy's disease, are normal. The NEE is notable for the often abundant presence of abnormal spontaneous activity, including fibrillation potentials and positive sharp waves, fasciculation potentials, and complex repetitive discharges. Motor unit morphology is abnormal, with polyphasic motor units and large amplitude and duration MUAPs when the disease is slowly progressive. Recruitment in affected muscles is reduced with abnormally rapidly firing motor units. To diagnose a widespread disorder of the motor neurons, abnormalities must be present in multiple muscles with different nerve root and peripheral nerve innervation in multiple limbs. The Lambert Criteria and the El Escorial Criteria are the two most widely accepted sets of electrodiagnostic criteria for ALS. The electrodiagnostic diagnosis must be supported by appropriate history and physical examination findings and the exclusion, via neuroimaging and laboratory testing, of other diseases that may mimic a generalized disorder of the motor neurons.

Progress toward poliomyelitis eradication--Egypt, 2002

Since the World Health Assembly resolved in 1988 to eradicate poliomyelitis globally, the number of countries in which polio is endemic has declined 94% from 125 countries to seven. The estimated number of wild poliovirus-positive cases worldwide has decreased >99%, and three World Health Organization (WHO) regions (Americas, European, and Western Pacific) are now certified as polio-free. Substantial progress has been made in the Eastern Mediterranean Region, where poliovirus is endemic in four (Afghanistan, Egypt, Pakistan, and Somalia) of 23 countries. This report summarizes progress during 2002 toward polio eradication in Egypt, where several independent chains of wild poliovirus type 1 (P1) transmission continue to circulate despite a long history of eradication efforts. The findings indicate that surveillance and vaccination activities have improved substantially and highlight the need for further improvements to interrupt poliovirus transmission.