Wild Poliovirus Transmission in Bordering Areas of Iran, Iraq, Syria, and Turkey, 1997-June 1998

The European and Eastern Mediterranean regions of the World Health Organization (WHO) have made substantial progress toward the goal of eradicating poliomyelitis by 2000 (1-3). As of June 1998, only two foci of known wild poliovirus transmission remained in the border areas of these two WHO regions: southeastern Turkey/northern Iraq and Tadjikistan/Afghanistan. This report summarizes progress toward interruption of wild poliovirus transmission in the bordering areas of the Islamic Republic of Iran, the Republic of Iraq, the Syrian Arab Republic, and Turkey.

Iran. Since 1992, Iran has consistently reported high routine vaccination coverage of infants (greater than or equal to 94%) with three doses of oral poliovirus vaccine (OPV3). Annual National Immunization Days (NIDs) * since 1994 achieved high coverage (greater than 98%) among children aged less than 5 years. Supplementary rounds in selected high-risk provinces covered approximately 3 million children in 1996 and 1997. During October-November 1997, approximately 200,000 children were targeted during cross-border mopping-up vaccination campaigns ** in the three Iranian provinces bordering Turkey and northern Iraq (West Azarbaijan, Kordestan, and Kermanshah) (Figure_1).

Since 1995, the rate of reported cases of nonpolio acute flaccid paralysis (AFP) in Iran has exceeded 1.0 case per 100,000 children aged less than 15 years, the WHO-established minimum nonpolio AFP rate (4). The three border provinces achieved nonpolio AFP rates of 0.9-1.3 cases per 100,000 in 1997. In the same year, the percentage of persons with AFP from whom adequate stool specimens *** were collected was 73% in Iran overall and 81% in the three border provinces (Table_1).

The number of reported virologically confirmed cases of wild poliovirus was 12 in 1996, 13 in 1997, and two as of June 1998. During 1997-June 1998, a total of 13 of 15 wild-virus associated cases were reported from southeastern Iranian provinces and were frequently linked epidemiologically to Afghanistan and Pakistan. Wild poliovirus type 1 (P1) was isolated from one case in 1997 reported from West Azarbaijan, bordering Turkey and northern Iraq, and from one case in Teheran. Wild P1 strains isolated from Iran in 1997, including the isolate from West Azarbaijan, were closely related genetically to isolates obtained during 1997 in Pakistan.

Iraq. Since 1995, routine OPV3 coverage in Iraq has been greater than 90%. Dohuk, Erbil, Ninevah, Suleymaniyah, and Tamim governorates in northern Iraq border with Iran, Syria, and Turkey. Since 1993, routine OPV3 coverage in Dohuk, Erbil, and Suleymaniyah has been 60%-70%, and coverage in Ninevah and Tamim has been 80%-90%. Since 1995, reported annual NIDs coverage has been greater than 90% in Iraq. In Erbil, Dohuk, and Suleymaniyah, reported NIDs coverage was 70%-80% during 1995-1997 and greater than 80% for the 1998 NIDs. During November-December 1997, two rounds of cross-border vaccination in these three northern governorates achieved coverage of 58% and 73%, respectively.

Iraq reported a nonpolio AFP rate of 1.5 in 1997, compared with 0.4 in 1996. Three of the five northern governorates (Erbil, Ninevah, and Tamim) met or exceeded a rate of 1.0; AFP surveillance in Dohuk and Suleymaniyah is not yet functional (Table_1). In 1997, adequate stool specimens were collected from 76% of persons with AFP nationwide and from 62% of persons with AFP in the northern governorates.

All 24 polio cases reported from Iraq in 1996 were confirmed clinically. Two of 28 cases reported in 1997 were confirmed by isolation of wild P1; one of these two cases was reported from Ninevah governorate in the north and was linked genetically with 1997 isolates from Mardin province, southeastern Turkey. As of mid-June 1998, no cases of polio or wild poliovirus isolates had been reported from Iraq.

Syria. Routine OPV3 coverage in Syria has been reported at greater than 90% since 1995, and high coverage (greater than 95%) has been achieved during annual NIDs since 1993. Supplementary rounds of OPV vaccination were conducted in four high-risk governorates during 1996-1997. As part of cross-border vaccination activity during October-November 1997, Syria conducted extensive house-to-house mopping-up vaccination campaigns in selected districts of four governorates bordering Turkey and Iraq. In 1997, of these four governorates, only Aleppo reported a nonpolio AFP rate of less than 1.0 (Table_1). In 1997, the percentage of AFP cases with adequate stool specimens collected was 55% overall and 78% in the four border governorates. No cases of polio have been reported from Syria during 1996, 1997, and through mid-June 1998.

Turkey. OPV3 coverage was 79% in 1997, with substantial variation among the 80 provinces. In six southeastern provinces bordering Syria, Iraq, and Iran, OPV3 coverage increased overall in 1997, but ranged from 8% in Hakkari to 67% in Sanli Urfa. NIDs coverage greater than 80% was achieved in at least 58 of 80 provinces each year during 1995-1997. In 1998, NID coverage nationally was greater than or equal to 93% for each round, and in Mardin and Sanli Urfa provinces combined was 79% and 81% for each round, respectively. In October and November 1997, mopping-up campaigns were conducted in 28 provinces along the border and other high-risk provinces throughout Turkey, with overall reported coverage of greater than 80%. However, coverage was less than 80% in nine (32%) of the participating provinces.

In 1997, the nonpolio AFP rate was 0.6 overall and 1.1 in the border and other high-risk provinces (Table_1). Through June 1998, the national annualized nonpolio AFP rate was 1.1.

In 1997, six polio cases with wild P1 were reported in the southeast province of Mardin. Through June 1998, five additional cases with wild P1 were reported from Sanli Urfa. These isolates were genetically similar to the 1997 isolate from northern Iraq and the 1994 isolates from Turkey.

Reported by: Offices of the World Health Organization for the Eastern Mediterranean and European regions; Global Program for Vaccines and Immunization, Geneva, Switzerland. Diagnostic Laboratory for Infectious Diseases, National Institute of Public Health and the Environment, Bilthoven, Netherlands. Respiratory and Enteric Viruses Br, Div of Viral and Rickettsial Diseases, National Center for Infectious Diseases; Vaccine Preventable Disease Eradication Div, National Immunization Program, CDC.

Editorial Note

Editorial Note: Since 1995, Iran, Iraq, Syria, and Turkey have participated in Operation MECACAR, a concerted effort to synchronize NIDs among 18 contiguous countries of the European and Eastern Mediterranean regions (5). These four countries conducted supplementary vaccination campaigns in adjoining border provinces and governorates during October-December 1997. These coordinated efforts, along with improved AFP surveillance, have reduced substantially transmission of wild poliovirus. Within these four countries, one area of transmission remains in southeastern Turkey/northern Iraq.

Genomic sequencing data indicate that southeastern Turkey and northern Iraq share a common reservoir of wild P1 along their national borders. Challenges to polio eradication in this area include ongoing armed conflict, frequent population movements, difficult terrain, and poor access to health-care services. In addition to Turkey and Iraq, culturally linked population groups also reside in adjacent border areas of Iran and Syria. Despite improvements in AFP surveillance, particularly in the border governorates, wild poliovirus has not been isolated in Syria since 1995. Genetic analysis of viral isolates obtained from Iran during 1997 suggests that wild-virus-associated cases are associated with reintroduction of wild poliovirus from neighboring Afghanistan and Pakistan, where wild poliovirus circulation is still widespread.

In the border provinces of southeastern Turkey and the three governorates of northern Iraq, measures are being taken by the respective ministries of health, WHO, and United Nations Children's Fund (UNICEF) to increase the effectiveness of both routine and supplementary OPV vaccination and to strengthen AFP surveillance. Interruption of poliovirus transmission in this area will require high levels of commitment within the countries and among the coalition of partner agencies ****. Intensive, synchronized supplementary vaccination in these and other border areas with poliovirus transmission is necessary to eliminate remaining poliovirus reservoirs.

References

1. CDC. Progress toward poliomyelitis eradication -- Europe and Central Asian Republics, 1997-May 1998;47:504-8.

2. CDC. Progress toward poliomyelitis eradication -- Eastern Mediterranean Region, 1996-1997. MMWR 1997;46:793-7.

3. CDC. Progress toward poliomyelitis eradication -- Turkey, 1994-1997. MMWR 1998;47:116-20.

4. CDC. Progress toward global eradication of poliomyelitis, 1997. MMWR 1998;47:414-9.

5. CDC. Mass vaccination with oral polio vaccine -- Asia and Europe, 1995. MMWR 1995;44:234-6.

* Mass campaigns over a short period (days to weeks) in which two doses of oral poliovirus vaccine are administered to all children aged less than 5 years, regardless of prior vaccination history, with an interval of 4-6 weeks between doses.

** Focal mass campaign in high-risk areas over a short period (days to weeks) in which two doses of OPV are administered during house-to-house visits to all children in the target age group, regardless of previous vaccination history, with an interval of 4-6 weeks between doses.

*** Two stool specimens collected at an interval of at least 24 hours within 14 days of onset of paralysis. The WHO-recommended target is collection of adequate stool specimens from at least 80% of persons with AFP.

**** WHO, UNICEF, Rotary International, U.S. Agency for International Development, CDC, and other national and international organizations.

+------------------------------------------------------------------- -------+ |             | | Errata: Vol. 47, No. 28 | | ======================= | |             | | SOURCE:47(29);619 DATE:Jul 31 1998 | |             | | In the article "Wild Poliovirus Transmission in Bordering Areas of | | Iran, Iraq, Syria, and Turkey, 1997-June 1998," on page 589 in Figure | | 1, cases with onset in 1997 were omitted from provinces labeled A, F, | | I, and R. Following is the corrected figure Figure_1e. | |             | +------------------------------------------------------------------- -------+

TABLE 1. Number of reported cases of acute flaccid paralysis (AFP) and confirmed poliomyelitis*, nonpolio AFP rate, and
percentage of persons with reported AFP with two stool specimens, by year, country, and selected provinces/governorates
-- Iran, Iraq, Syria, and Turkey, January 1997-June 15, 1998
============================================================================================================================
                                          1997                                            1998
                       --------------------------------------------    -----------------------------------------------
                                                          % persons                                          % Persons
                                                          with AFP                                           with AFP
                                     No.                  with two                   No.      Annualized     with two
Country/                No. AFP   confirmed   Nonpolio     stool        No. AFP   confirmed     Nonpolio      stool
 Province/Governorate    cases      cases+    AFP rate&   specimens@    cases       cases+      AFP rate&    specimens
----------------------------------------------------------------------------------------------------------------------
Iran                     415       13 (13)       1.4         73%        155         2 (2)          1.3           68%
 Kermanshah                8        0            1.1         88%          2         0              0.9          100%
 Kordestan                 8        0            1.3        100%          2         0              1            100%
 W. Azarbaijan            16        1 ( 1)       0.9         69%          5         0              0.9           60%

Iraq                     162       21 ( 2)       1.5         76%         59         0              1.6           75%
 Dohuk                     1        0            0.3          0           0         0              0             --
 Erbil                     6        0            1           83%          1         0              0.5           100%
 Suleymaniyah              0        0            0           --           0         0              0             --
 Ninevah                  18       10 ( 1)       1           55%          5         0              1.5           100%
 Tamim                     4        1            1           75%          1         0              0.8           100%

Syria                     80        0            1.3         55%         38         0              1.4            75%
 Aleppo                   11        0            0.9         80%          5         0              1.2            80%
 Dar El Zour               3        0            1           67%          0         0              0              --
 Hasakah                   7        0            1.4         86%          0         0              0              --
 Raqqa                     2        0            1           50%          1         0              1.5             0

Turkey                   141        6 ( 6)       0.6         65%        105         5 (5)          1.1             71%
 Agri                      0        0            0           --           0         0              0               --
 Hakkari                   0        0            0           --           0         0              0               --
 Mardin                    9        6 ( 6)       1.4         22%           3        0              3.1             33%
 Sanli Urfa                7        0            1.7         71%          14        5 (5)          4.8             89%
 Sirnak                    0        0            0           --            2        0              4.2             50%
 Van                       1        0            0.4         100%          1        0              0.9            100%

Other high risk
 provinces/
 governorates              5        0            0.5          60%         13        --             2.6             50%
---------------------------------------------------------------------------------------------------------------------
* A confirmed case of polio is defined as AFP and at least one of the following: 1) laboratory- confirmed wild poliovirus infection     2) residual
  paralysis at 60 days  3) death, or 4) no follow up investigation at 60 days. In Turkey and Iran       a confirmed case was laboratory- confirmed
  wild poliovirus infection.
+ Numbers in paranthesis are laboratory-confirmed cases.
& Number of AFP cases per 100,000 population aged <15 years. Minimum expected rate is 1 case of nonpolio AFP per 100,000 per year.
@ Two stool specimens collected at an interval of at least 24 hours within 14 days of paralysis onset.
============================================================================================================================

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