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n of a testing approach in countries of WHO regions h WPV circulation that reduces poliovirus confirmation he by 50% (to 21 days), compared with previous thods. The percentage of stool specimens tested from $$ io-endemic regions in laboratories with capacity for both is isolation in cell culture and differentiation of wild or cine-like viruses increased from 57% in 2006 to 69% 2007.

PV Incidence

As of April 30, 2008, a total of 1,310 polio cases with set of paralysis in 2007 had been reported worldwide ble), a decrease of 34% from the 1,997 cases reported 2006. With the strategic emphasis on WPV1 elimina1, WPV1 cases decreased 81% from 1,666 in 2006 to I cases in 2007; however, WPV3 cases tripled from 331 2006 to 989 in 2007 (Figure 1). The reported number polio-affected districts in all countries decreased 26% m 463 in 2006 to 342 in 2007. A total of 106 (8%)

dditional information available at http://www.who.int/immunization_ monitoring/Supplement_polio_lab_manual.pdf.

cases in 2007 were in countries where WPV was reintroduced through importation, compared with 1,301 (40%) of 3,234 cases during 2004-2005 (9). As of April 30, a total of 134 WPV1 cases and 220 WPV3 cases with onset of paralysis in 2008 had been reported (Figure 2), compared with 64 WPV1 cases and 66 WPV3 cases reported during the same period in 2007.

India. Reported WPV1 cases declined 87% in India, from 646 in 2006 to 83 in 2007, associated with expanded use of mOPV1 (3). Western Uttar Pradesh, which had been the primary reservoir of WPV1 circulation in recent years, reported five WPV1 cases in 2007. The number of WPV1affected districts declined 61%, from 114 in 2006 to 45 in 2007. However, a WPV3 outbreak involving Uttar Pradesh and spreading to Bihar resulted in an increase in WPV3 cases from 28 in 2006 to 787 in 2007; the number of WPV3-affected districts increased from seven in 2006 to 77 in 2007. Primary use of mOPV1 in SIAs during 2006-2008 has accelerated the decline in WPV1 cases; as of April 30, 2008, only four cases had been reported in 2008 (in New Delhi, Orissa, Bihar, and West Bengal), compared with 26 cases during the same period in 2007.

BLE. Number and rate of acute flaccid paralysis (AFP) cases in 2007 and number of wild poliovirus (WPV)-confirmed cases of iomyelitis in 2007, January-April 2007, and January-April 2008, by World Health Organization (WHO) region and country*

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ata reported to WHO as of April 30, 2008. Only countries with WPV in 2007 are included. Central African Republic has reported a WPV1 case in 2008. Then averaging global, regional, or national surveillance indicators, suboptimal performance-quality indicators in smaller areas might be masked. er 100,000 persons aged <15 years.

wo stool specimens collected at an interval of >24 hours within 14 days of paralysis onset and adequately shipped to a WHO-accredited laboratory. ountries where WPV transmission has never been interrupted.

ending final allocation of case.

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* Data reported for 2008 to the World Health Organization as of April 30, 2008 (N = 354).

† Excludes polioviruses detected by environmental surveillance and vaccine-derived polioviruses.

§ Central African Republic.

1 Democratic Republic of the Congo.

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_onthly reported WPV3 cases decreased from a peak of 5 cases in December 2007 to 32 cases in March 2008; netheless, 199 cases of WPV3 had been reported in 2008, marily in Bihar, compared with 13 during the same iod in 2007.

Nigeria. Reported WPV1 cases declined 86% in Nigefrom 843 in 2006 to 116 in 2007, and reported WPV3 es declined 39%, from 277 in 2006 to 169 in 2007. e number of WPV1-affected districts declined 62%, from 3 in 2006 to 78 in 2007. The number of WPV3-afted districts declined 14%, from 125 in 2006 to 108 in 07; however, WPV3 outbreaks and isolated cases occurred districts in certain previously polio-free southern states. of April 30, 2008, a total of 113 WPV1 cases and 13 'V3 cases with onset in 2008 had been reported, comed with 15 WPV1 cases and 46 WPV3 cases reported the same period in 2007.

'akistan and Afghanistan. WPV circulates between kistan and Afghanistan. WPV1 cases decreased in Paki1, from 20 in 2006 to 19 in 2007, whereas WPV3 cases reased 35%, from 20 in 2006 to 13 in 2007. Twelve ricts were affected with WPV1 in both 2006 and 2007, ereas the number of WPV3-affected districts declined %, from 14 in 2006 to nine in 2007. Transmission has ained confined to two known virus reservoirs along the kistan-Afghanistan border, with the southern reservoir -ending well into nonborder districts in southern Pakia provinces (4). By April 30, 2008, four WPV1 cases h onset in 2008 had been reported in Pakistan, comed with two WPV1 and five WPV3 cases during the ne period in 2007.

Although access during SIAS in Afghanistan did not ɔrove until late in 2007 in the areas with security prob1s, the number of WPV1 cases decreased 79%, from 29 es in 2006 to six in 2007; however, the number of WPV3 es increased from two cases in 2006 to 11 in 2007 (4). 'V1 and WPV3 transmission continued in the SouthRegion, and two cases of WPV1 were reported in the stern Region in areas bordering Pakistan. The number WPV1-affected districts decreased 65%, from 17 in 2006 six in 2007, whereas the number of WPV3-affected dists increased from two in 2006 to nine in 2007 (4). As April 30, 2008, four WPV1 cases and one WPV3 case h onset in 2008 had been reported in Afghanistan, comed with no WPV cases during the same period in 2007. Other countries. Thirteen countries, once polio-free, orted WPV cases in 2006 following WPV importation";

ngola, Bangladesh, Chad, Democratic Republic of the Congo, Ethiopia, idonesia, Kenya, Namibia, Nepal, Niger, Somalia, Sudan, and Yemen.

six of these countries reported polio cases in 2007 (Angola, Chad, Democratic Republic of the Congo [DRC], Nepal, Niger, and Somalia).*** In Angola and DRC, transmission in 2007 (with eight and 41 cases, respectively) followed importation of WPV1 originating in India; as of April 30, 2008, Angola and DRC each had reported one WPV1 case in 2008, compared with no cases and 12 cases, respectively, during the same period in 2007. In addition, two WPV3 cases were identified in Angola in 2008, both with onset in March, also genetically indicating origin in India. In Chad, circulation of WPV1 (18 cases) and WPV3 (three cases) in 2007 continued after introduction from Nigeria in past years and 2007. In Niger, with a total of 10 WPV1 cases and one WPV3 case, certain importations from neighboring Nigeria resulted in clusters of cases from internal transmission. As of April 30, 2008, two WPV3 cases had been reported in 2008 from Chad and five WPV1 cases from Niger. Nepal, bordering India, had five sporadic ttt WPV3 importations in 2007; as of April 30, 2008, three WPV3 cases had been reported in Nepal in 2008. Somalia reported eight WPV1 cases in 2007 but has had >1 year without detection of cases after an outbreak during July 2005-March 2007.

After several years without polio, Burma (Myanmar) had an outbreak of 11 WPV1 cases in 2007, with the last reported case occurring in May. Sudan, which had no reported polio cases in 2006, reported a single confirmed case of WPV1 circulating in Chad. However, as of April 30, 2008, a case with onset in February 2008 occurred on the Sudan-Ethiopia border; the exact location is under investigation. Genomic sequencing analysis indicates years of undetected WPV1 chains of transmission within Sudan, western Ethiopia, or both; the closest genetic relationship is with WPV1 isolated from a patient in Sudan in 2004. Reported by: Polio Eradication Dept, World Health Organization, Geneva, Switzerland. Div of Viral Diseases and Global Immunization Div, National Center for Immunization and Respiratory Diseases, CDC. Editorial Note: In 2007, substantial progress was made toward limiting the geographic extent and number of cases of WPV1 transmission in India as a result of intensive SIAS with increased use of mOPV1 in affected areas. However, WPV3 transmission increased in Uttar Pradesh and Bihar because of the intended focus on elimination of WPV1, limited mOPV3 supply in India, restricted tOPV use in

As determined by genetic lineage, 33 of 35 separate importations have been stopped (defined as lack of detection of related WPV cases since September 30, 2007) in 11 of the 13 countries; transmission of imported poliovirus lineages circulating in 2006 continues in Chad and Democratic Republic of the Congo. *** Additionally, Central African Republic, last reporting WPV1 in 2004 (9), has identified a WPV1 case in the capital, Bangui, with onset in April 2008.

SIAs in 2007, and underlying insufficient routine vaccination coverage (3). Combined use of mOPV1, mOPV3, and tOPV is expected to lead to interruption of WPV1 transmission and a substantial decrease in WPV3 transmission in India by the end of 2008.

WPV1 cases and affected districts also decreased substantially in Nigeria during 2007, compared with 2006. However, this decrease has not been sustained; more WPV1 cases have occurred in 2008 than during the same period in 2007. The proportion of children entirely missed during SIAS and routine vaccinations remains high (>10%) in certain states in Nigeria. Major efforts to strengthen routine vaccination services and the quality of SIA implementation are continuing (2).

The number of confirmed WPV1 cases decreased nearly 80% in Afghanistan but has not substantially decreased in Pakistan; security and access problems in border areas of Afghanistan and Pakistan are continuing, but improved access (compared with early 2007) in Afghanistan and continuing coordinated cross-border vaccination efforts might produce better results in 2008. Operational problems in vaccinating children in secure areas of Pakistan also are being addressed (4).

The WHO stakeholders meeting in February 2007 established three milestones for the end of 2007 (6). The first milestone was to reduce the number of affected districts in the four polio-endemic countries by >50% compared with 2006. A 59% reduction in WPV1-affected districts has occurred, but WPV3-affected districts have increased 37% (for a net 24% reduction in WPV-affected districts).

The second milestone, reducing the proportion of zerodose children in polio-affected areas to less than that in polio-free areas, has been met in India and major portions of affected areas in Afghanistan and Pakistan. However, this milestone has not been achieved in the high-risk areas of Nigeria and Afghanistan.

The third milestone involves interrupting transmission in all 13 countries with polio cases resulting from imported WPV in 2006. WPV transmission continued in Chad and DRC through 2007 and into 2008. New cases and transmission were reported in Angola and Niger during 2007, and Nepal experienced repeated WPV3 importations in 2007. However, Sudan or western Ethiopia, or both, have had longstanding WPV1 circulation since importation of WPV of Nigerian origin into Sudan in 2004 (9) without detection during 2006-2007, which indicates that surveillance quality should be monitored within each country by subnational area and strengthened where needed.

Ongoing WPV transmission in Angola, Chad, DRC, ar. Sudan and/or Ethiopia requires continuing efforts to ever come the operational impediments limiting the vaccin tion of children.

The technical feasibility of polio eradication has been der onstrated repeatedly by the ability to interrupt WPV trar. mission in some of the most difficult to access and insect areas in the world, including areas that have limited heat infrastructure, such as Somalia. In 2007, the feasibility polio eradication was highlighted by the substantial progres toward WPV1 interruption in India. The concerted effort: interrupt WPV1 transmission worldwide continues in 2005 with a focus on administering mOPV1 in SIAS, combinat with periodic use of mOPV3 and tOPV. Sustained comm ment by governments and international partners wit ongoing program evaluation and adaptation to changing cr cumstances is crucial for progress to continue.

References

1. CDC. Progress toward interruption of wild poliovirus transmissorworldwide, January 2006-May 2007. MMWR 2007;56:682-5.

2. CDC. Progress toward poliomyelitis eradication-Nigeria, 2005–20 MMWR 2007;56:278-81.

3. CDC. Progress toward poliomyelitis eradication-India, January 2006September 2007. MMWR 2007;56:1187-91.

4. CDC. Progress toward poliomyelitis eradication—Pakistan and Afghan stan, 2007. MMWR 2008;57:315–9.

5. CDC. Apparent global interruption of wild poliovirus type 2 transm sion. MMWR 2001;50:222-4.

6. World Health Organization. The case of completing polio eradicat 2007. Available at http://www.polioeradication.org/content/publicat_15 thecase_final.pdf.

7. World Health Organization. WHO vaccine-preventable diseases mettoring system: 2007 global summary. Geneva, Switzerland: Were Health Organization;2007. Available at http://whqlibdoc.who.int 2007/who_ivb_2007_eng.pdf.

8. World Health Organization. Advisory committee on polio erac tion-standing recommendations for responding to circulating po.. ruses in polio-free areas. Wkly Epidemiol Rec 2005;80:330–1. 9. CDC. Resurgence of wild poliovirus type 1 transmission and cers quences of importation-21 countries, 2002-2005. MMWR 200 55:145-50.

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fewer than 150 cases reported per year since 1997 (1). ring 2000-2007,* a total of 29-116 measles cases ean: 62, median: 56) were reported annually. However, ing January 1-April 25, 2008, a total of 64 confirmed asles cases were preliminarily reported to CDC, the most orted by this date for any year since 2001. Of the - cases, 54 were associated with importation of measles Im other countries into the United States, and 63 of the patients were unvaccinated or had unknown or undocunted vaccination status. This report describes the 64 cases 1 provides guidance for preventing measles transmission 1 controlling outbreaks through vaccination, infection trol, and rapid public health response. Because these es resulted from importations and occurred almost lusively in unvaccinated persons, the findings underre the ongoing risk for measles among unvaccinated peris and the importance of maintaining high levels of cination.

Measles cases in the United States are reported by state lth departments preliminarily to CDC, and confirmed es are reported officially via the National Notifiable Dise Surveillance System, using standard case definitions 1 case classifications. Cases are considered importation ɔciated if they are 1) acquired outside the United States ., international importation) or 2) acquired inside the ited States and either epidemiologically linked via a chain transmission to an importation or accompanied by viroic evidence of importation (i.e., a chain of transmission m which a measles virus is identified that is not endemic the United States). Other cases in the United States are ssified as having an unknown source.

During January 1-April 25, 2008, a total of 64 prelimiy confirmed measles cases were reported from the folving areas: New York City (22 cases), Arizona (15), lifornia (12), Michigan and Wisconsin (four each), waii (three), and Illinois, New York state, Pennsylvania, 1 Virginia (one each) (Figure). Patients ranged in age m 5 months to 71 years; 14 patients were aged 2 months, 18 were aged 1-4 years, 11 were aged 19 years, 18 were aged 20-49 years, and three were aged ) years, including one U.S. resident born before 1957.$

sed on MMWR surveillance summaries (2000–2006) and CDC unpublished visional data as of December 31, 2007.

easles clinical case definition: an illness characterized by a generalized culopapular rash, a temperature of ≥101°F (≥38.3°C) and cough, coryza, or 1junctivitis. A case is considered confirmed if it is laboratory confirmed (using ologic or virologic methods) or if it meets the clinical case definition and is demiologically linked to a confirmed case.

e other two cases in persons aged ≥50 years occurred in a U.S. resident aged years and a visitor from Switzerland aged 71 years.

Fourteen (22%) patients were hospitalized; no deaths were reported. Transmission occurred in both health-care and community settings. One of the 44 patients for whom transmission setting was known was an unvaccinated healthcare worker who was infected in a hospital. Seventeen (39%) were infected while visiting a health-care facility, including a child aged 12 months who was exposed in a physician's office when receiving a routine dose of measles, mumps, and rubella (MMR) vaccine.

Fifty-four (84%) of the 64 measles cases were importation associated: 10 (16%) of the 64 were importations (five in visitors to the United States and five in U.S. residents traveling abroad) from Switzerland (three), Israel (three), Belgium (two), and India and Italy (one each); 29 (45%) cases were epidemiologically linked to importations; and 15 (23%) cases had virologic evidence of importation. The remaining 10 (16%) cases were from unknown sources; however, all occurred in communities with importationassociated cases. Specimens from 14 patients were genotyped at CDC, and four different genotypes were identified: three from Arizona (genotype D5), three from California (D5), five from New York City (one in a case epidemiologically linked to an imported case from Belgium and four in cases in communities where importations from Israel had occurred; all D4), two from Wisconsin (H1), and one from Michigan (D5).

Fifty-six of the 64 measles cases reported in 2008 have occurred in five outbreaks (defined as three or more cases linked in time or place). In New York City, an outbreak of 22 cases has been reported, including four importations and 18 other cases (10 importation associated). In Arizona, 15 cases have been reported; the index patient was an unvaccinated adult visitor from Switzerland. In San Diego, California, 11 cases have been reported, and an additional case spread to Hawaii; the index patient in the San Diego outbreak was an unvaccinated child who had traveled to Switzerland. In Michigan, four cases have been reported; the index patient was an unvaccinated youth aged 13 years with an unknown source of infection. In Wisconsin, four cases have been reported; the index patient was a person aged 37 years with unknown vaccination status who likely was exposed to a Chinese visitor with measlescompatible illness.

Sixty-three of the 64 patients were unvaccinated or had unknown or undocumented vaccination status, and one patient had documentation of receiving 2 doses of MMR vaccine. None of the five patients who were visitors to the

Two adults in the Arizona outbreak reported receipt of 1 and 2 vaccine doses, respectively, but lacked documentation.

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