Progress Toward Poliomyelitis Eradication - Pakistan, January 2022-June 2023.

Since the establishment of the Global Polio Eradication Initiative in 1988, Pakistan remains one of only two countries (along with Afghanistan) with continued endemic transmission of wild poliovirus (WPV). This report describes Pakistan's progress toward polio eradication during January 2022-June 2023. During 2022, Pakistan reported 20 WPV type 1 (WPV1) cases, all of which occurred within a small geographic area encompassing three districts in south Khyber Pakhtunkhwa. As of June 23, only a single WPV1 case from Bannu district in Khyber Pakhtunkhwa province has been reported in 2023, compared with 13 cases during the same period in 2022. In addition, 11 WPV1 isolates have been reported from various environmental surveillance (ES) sewage sampling sites to date in 2023, including in Karachi, the capital of the southern province of Sindh. Substantial gaps remain in the quality of supplementary immunization activities (SIAs), especially in poliovirus reservoir areas. Despite the attenuation and apparently limited geographic scope of poliovirus circulation in Pakistan, the isolation of WPV1 from an ES site in Karachi is cause for concern about the actual geographic limits of transmission. Interrupting WPV1 transmission will require meticulous tracking and sustained innovative efforts to vaccinate children who are regularly missed during SIAs and rapidly responding to any new WPV1 isolations.

Polio vaccination activities in conflict-affected areas.

Conflict poses a threat to the stability of health-care systems around the world. Within the context of immunization service delivery, conflict-affected geographies are often dogged by recurrent disease outbreaks due to the inability to administer life-saving vaccines to children residing in these areas. Essential immunization coverage is often poor in conflict-affected geographies, and within the specific context of the Global Polio Eradication Initiative (GPEI), multiple rounds of supplementary immunization activities are often needed to compensate for the inability to provide adequate immunization services. In order to implement polio vaccination activities, GPEI has often resorted to innovative approaches to reach and vaccinate children in security-compromised areas. This article examines the approaches adopted by the global polio program in conducting vaccination activities in conflict-affected geographies with the aim of understanding how they have influenced the successes and setbacks of the program in its bid to eradicate all polioviruses.

Progress Toward Poliomyelitis Eradication - Pakistan, January 2021-July 2022.

After reporting a single wild poliovirus (WPV) type 1 (WPV1) case in 2021, Pakistan reported 14 cases during April 1-July 31, 2022. Pakistan and Afghanistan are the only countries where endemic WPV transmission has never been interrupted (1). In its current 5-year strategic plan, the Global Polio Eradication Initiative (GPEI) has set a goal of interrupting all WPV1 transmission by the end of 2023 (1-3). The reemergence of WPV cases in Pakistan after 14 months with no case detection has uncovered transmission in southern Khyber Pakhtunkhwa province, the most historically challenging area. This report describes Pakistan's progress toward polio eradication during January 2021-July 2022 and updates previous reports (4,5). As of August 20, 2022, all but one of the 14 WPV1 cases in Pakistan during 2022 have been reported from North Waziristan district in Khyber Pakhtunkhwa. In underimmunized populations, excretion of vaccine virus can, during a period of 12-18 months, lead to reversion to neurovirulence, resulting in circulating vaccine-derived polioviruses (cVDPVs), which can cause paralysis and outbreaks. An outbreak of cVDPV type 2 (cVDPV2), which began in Pakistan in 2019, has been successfully contained; the last case occurred in April 2021 (1,6). Despite program improvements, 400,000-500,000 children continue to be missed during nationwide polio supplementary immunization activities (SIAs),* and recent isolation of poliovirus from sewage samples collected in other provinces suggests wider WPV1 circulation during the ongoing high transmission season. Although vaccination efforts have been recently complicated by months of flooding during the summer of 2022, to successfully interrupt WPV1 transmission in the core reservoirs in southern Khyber Pakhtunkhwa and reach the GPEI goal, emphasis should be placed on further improving microplanning and supervision of SIAs and on systematic tracking and vaccination of persistently missed children in these reservoir areas of Pakistan.

Progress Toward Poliomyelitis Eradication - Pakistan, January 2020-July 2021.

When the Global Polio Eradication Initiative began in 1988, wild poliovirus (WPV) transmission was occurring in 125 countries; currently, only WPV type 1 (WPV1) transmission continues, and as of August 2021, WPV1 transmission persists in only two countries (1,2). This report describes Pakistan's progress toward polio eradication during January 2020-July 2021 and updates previous reports (3,4). In 2020, Pakistan reported 84 WPV1 cases, a 43% reduction from 2019; as of August 25, 2021, Pakistan has reported one WPV1 case in 2021. Circulating vaccine-derived poliovirus (cVDPV) emerges as a result of attenuated oral poliovirus vaccine (OPV) virus regaining neurovirulence after prolonged circulation in underimmunized populations and can lead to paralysis. In 2019, 22 cases of cVDPV type 2 (cVDPV2) were reported in Pakistan, 135 cases were reported in 2020, and eight cases have been reported as of August 25, 2021. Because of the COVID-19 pandemic, planned supplementary immunization activities (SIAs)* were suspended during mid-March-June 2020 (3,5). Seven SIAs were implemented during July 2020-July 2021 without substantial decreases in SIA quality. Improving the quality of polio SIAs, vaccinating immigrants from Afghanistan, and implementing changes to enhance program accountability and performance would help the Pakistan polio program achieve its goal of interrupting WPV1 transmission by the end of 2022.

Stopping a polio outbreak in the midst of war: Lessons from Syria.

BACKGROUND: Outbreaks of circulating vaccine-derived polioviruses (cVDPVs) pose a threat to the eventual eradication of all polioviruses. In 2017, an outbreak of cVDPV type 2 (cVDPV2) occurred in the midst of a war in Syria. We describe vaccination-based risk factors for and the successful response to the outbreak. METHODS: We performed a descriptive analysis of cVDPV2 cases and key indicators of poliovirus surveillance and vaccination activities during 2016-2018. In the absence of reliable subnational coverage data, we used the caregiver-reported vaccination status of children with non-polio acute flaccid paralysis (AFP) as a proxy for vaccination coverage. We then estimated the relative odds of being unvaccinated against polio, comparing children in areas affected by the outbreak to children in other parts of Syria in order to establish the presence of poliovirus immunity gaps in outbreak affected areas. FINDINGS: A total of 74 cVDPV2 cases were reported, with paralysis onset ranging from 3 March to 21 September 2017. All but three cases were reported from Deir-ez-Zor governorate and 84% had received < 3 doses of oral poliovirus vaccine (OPV). After adjusting for age and sex, non-polio AFP case-patients aged 6-59 months in outbreak-affected areas had 2.5 (95% CI: 1.1-5.7) increased odds of being unvaccinated with OPV compared with non-polio AFP case-patients in the same age group in other parts of Syria. Three outbreak response rounds of monovalent OPV type 2 (mOPV2) vaccination were conducted, with governorate-level coverage mostly exceeding 80%. INTERPRETATION: Significant declines in both national and subnational polio vaccination coverage, precipitated by war and a humanitarian crisis, led to a cVDPV2 outbreak in Syria that was successfully contained following three rounds of mOPV2 vaccination.

Using Nonpolio Enterovirus Detection to Assess the Integrity of Stool Specimens Collected From Acute Flaccid Paralysis Cases in Somalia During 2014-2017.

BACKGROUND: Despite insecurity challenges in Somalia, key indicators for acute flaccid paralysis (AFP) surveillance have met recommended targets. However, recent outbreaks of vaccine-derived polioviruses have raised concerns about possible gaps. We analyzed nonpolio enterovirus (NPEV) and Sabin poliovirus isolation rates to investigate whether comparing these rates can inform about the integrity of stool specimens from inaccessible areas and the likelihood of detecting circulating polioviruses. METHODS: Using logistic regression, we analyzed case-based AFP surveillance data for 1348 cases with onset during 2014-2017. We assessed the adjusted impacts of variables including age, accessibility, and Sabin-like virus isolation on NPEV detection. RESULTS: NPEVs were more likely to be isolated from AFP case patients reported from inaccessible areas than accessible areas (23% vs 15%; P = .01). In a multivariable model, inaccessibility and detection of Sabin-like virus were positively associated with NPEV detection (adjusted odds ratio [AOR], 1.75; 95% confidence interval [CI], 1.14-2.65; and AOR, 1.79; 95% CI, 1.07-2.90; respectively), while being aged ≥5 years was negatively associated (AOR, 0.42; 95% CI, 0.20-0.85). CONCLUSIONS: Rates of NPEV and Sabin poliovirus detection in inaccessible areas suggest that the integrity of fecal specimens tested for AFP surveillance in Somalia can generate useful AFP data, but uncertainties remain about surveillance system quality.

Progress Toward Poliomyelitis Eradication - Afghanistan, January 2018-May 2019.

Since October 2016, Afghanistan and Pakistan have been the only countries with reported cases of wild poliovirus type 1 (WPV1) (1). In Afghanistan, although the number of cases had declined during 2013-2016, the polio eradication program experienced challenges during 2017-2019. This report describes polio eradication activities and progress in Afghanistan during January 2018-May 2019 and updates previous reports (2,3). During May-December 2018, insurgent groups (antigovernment elements) banned house-to-house vaccination in most southern and southeastern provinces, leaving approximately 1 million children inaccessible to oral poliovirus vaccine (OPV) administration. During January-April 2019, vaccination targeting children at designated community sites (site-to-site vaccination) was permitted; however, at the end of April 2019, vaccination campaigns were banned nationally. During 2018, a total of 21 WPV1 cases were reported in Afghanistan, compared with 14 during 2017. During January-May 2019, 10 WPV1 cases were reported (as of May 31), compared with eight during January-May 2018. Sewage sample-testing takes place at 20 sites in the highest-risk areas for poliovirus circulation; 17 have detected WPV1 since January 2017, primarily in the southern and eastern provinces. Continued discussion with antigovernment elements to resume house-to-house campaigns is important to achieving polio eradication in Afghanistan. To increase community support for vaccination, collaboration among humanitarian service agencies to address other urgent health and basic needs is critical.

Update on Vaccine-Derived Poliovirus Outbreaks - Democratic Republic of the Congo and Horn of Africa, 2017-2018.

Widespread use of live attenuated (Sabin) oral poliovirus vaccine (OPV) has resulted in marked progress toward global poliomyelitis eradication (1). However, in underimmunized populations, extensive person-to-person transmission of Sabin poliovirus can result in genetic reversion to neurovirulence and paralytic vaccine-derived poliovirus (VDPV) disease (1). This report updates (as of February 26, 2019) previous reports on circulating VDPV type 2 (cVDPV2) outbreaks during 2017-2018 in the Democratic Republic of the Congo (DRC) and in Somalia, which experienced a concurrent cVDPV type 3 (cVDPV3) outbreak* (2,3). In DRC, 42 cases have been reported in four cVDPV2 outbreaks; paralysis onset in the most recent case was October 7, 2018 (2). Challenges to interrupting transmission have included delays in outbreak-response supplementary immunization activities (SIAs) and difficulty reaching children in all areas. In Somalia, cVDPV2 and cVDPV3 were detected in sewage before the detection of paralytic cases (3). Twelve type 2 and type 3 cVDPV cases have been confirmed; the most recent paralysis onset dates were September 2 (cVDPV2) and September 7, 2018 (cVDPV3). The primary challenge to interrupting transmission is the residence of >300,000 children in areas that are inaccessible for vaccination activities. For both countries, longer periods of surveillance are needed before interruption of cVDPV transmission can be inferred.

Progress Toward Poliomyelitis Eradication - Afghanistan, January 2017-May 2018.

Afghanistan, Pakistan, and Nigeria remain the only countries where transmission of endemic wild poliovirus type 1 (WPV1) continues (1). This report describes polio eradication activities, progress, and challenges to eradication in Afghanistan during January 2017-May 2018 and updates previous reports (2, 3). Fourteen WPV1 cases were confirmed in Afghanistan in 2017, compared with 13 in 2016; during January-May 2018, eight WPV1 cases were reported, twice the number reported during January-May 2017. To supplement surveillance for acute flaccid paralysis (AFP) and laboratory testing of stool samples, environmental surveillance (testing of sewage samples) was initiated in 2013 and includes 20 sites, 15 of which have detected WPV1 circulation. The number of polio-affected districts increased from six in 2016 to 14 in 2017 (including WPV1 cases and positive environmental samples). Access to children for supplementary immunization activities (SIAs) (mass campaigns targeting children aged <5 years with oral poliovirus vaccine [OPV], regardless of vaccination history), which improved during 2016 to early 2018, worsened in May 2018 in security-challenged areas of the southern and eastern regions. To achieve WPV1 eradication, measures to maintain and regain access for SIAs in security-challenged areas, strengthen oversight of SIAs in accessible areas to reduce the number of missed children, and coordinate with authorities in Pakistan to track and vaccinate mobile populations at high risk in their shared transit corridors must continue.

Strategic Response to an Outbreak of Circulating Vaccine-Derived Poliovirus Type 2 - Syria, 2017-2018.

Since the 1988 inception of the Global Polio Eradication Initiative (GPEI), progress toward interruption of wild poliovirus (WPV) transmission has occurred mostly through extensive use of oral poliovirus vaccine (OPV) in mass vaccination campaigns and through routine immunization services (1,2). However, because OPV contains live, attenuated virus, it carries the rare risk for reversion to neurovirulence. In areas with very low OPV coverage, prolonged transmission of vaccine-associated viruses can lead to the emergence of vaccine-derived polioviruses (VDPVs), which can cause outbreaks of paralytic poliomyelitis. Although WPV type 2 has not been detected since 1999, and was declared eradicated in 2015,* most VDPV outbreaks have been attributable to VDPV serotype 2 (VDPV2) (3,4). After the synchronized global switch from trivalent OPV (tOPV) (containing vaccine virus types 1, 2, and 3) to bivalent OPV (bOPV) (types 1 and 3) in April 2016 (5), GPEI regards any VDPV2 emergence as a public health emergency (6,7). During May-June 2017, VDPV2 was isolated from stool specimens from two children with acute flaccid paralysis (AFP) in Deir-ez-Zor governorate, Syria. The first isolate differed from Sabin vaccine virus by 22 nucleotides in the VP1 coding region (903 nucleotides). Genetic sequence analysis linked the two cases, confirming an outbreak of circulating VDPV2 (cVDPV2). Poliovirus surveillance activities were intensified, and three rounds of vaccination campaigns, aimed at children aged <5 years, were conducted using monovalent OPV type 2 (mOPV2). During the outbreak, 74 cVDPV2 cases were identified; the most recent occurred in September 2017. Evidence indicates that enhanced surveillance measures coupled with vaccination activities using mOPV2 have interrupted cVDPV2 transmission in Syria.

Strengthening Acute Flaccid Paralysis Surveillance Through the Village Polio Volunteers Program in Somalia.

Background: Surveillance for cases of acute flaccid paralysis (AFP) is a key strategy adopted for the eradication of polio. Detection of poliovirus circulation is often predicated on the ability to identify AFP cases and test their stool specimens for poliovirus infection in a timely manner. The Village Polio Volunteers (VPV) program was established in 2013 in a bid to strengthen polio eradication activities in Somalia, including AFP surveillance, given the country's vulnerability to polio outbreaks. Methods: To assess the impact of the VPV program on AFP surveillance, we determined case counts, case-reporting sources, and nonpolio AFP rates in the years before and after program introduction (ie, 2011-2016). We also compared the stool specimen adequacy rates and timeliness of cases reported by VPVs to those reported by other sources. Results: In the years after program introduction, VPVs accounted for a high proportion of AFP cases reported in Somalia. AFP case counts rose from 148 cases in 2012, the year before program introduction, to 279 cases in 2015, when VPVs accounted for 40% of reported cases. Further, from 2012 to 2015, the nonpolio AFP rate improved from 2.8 to 4.8 cases per 100000 persons aged <15 years. Stool specimen adequacy rates have been consistently high, and AFP cases have been detected in a timelier manner since the program was introduced. Conclusions: Given the impact of the VPV program on improving AFP surveillance indicators in Somalia, similar community-based programs could play a crucial role in enhancing surveillance activities in countries with limited healthcare infrastructure.

Fractional-Dose Inactivated Poliovirus Vaccine Campaign - Sindh Province, Pakistan, 2016.

Following the declaration of eradication of wild poliovirus (WPV) type 2 in September 2015, trivalent oral poliovirus vaccine (tOPV) was withdrawn globally to reduce the risk for type 2 vaccine-derived poliovirus (VDPV2) transmission; all countries implemented a synchronized switch to bivalent OPV (type 1 and 3) in April 2016 (1,2). Any isolation of VDPV2 after the switch is to be treated as a potential public health emergency and might indicate the need for supplementary immunization activities (3,4). On August 9, 2016, VDPV2 was isolated from a sewage sample taken from an environmental surveillance site in Hyderabad, Sindh province, Pakistan. Possible vaccination activities in response to VDPV2 isolation include the use of injectable inactivated polio vaccine (IPV), which poses no risk for vaccine-derived poliovirus transmission. Fractional-dose, intradermal IPV (fIPV), one fifth of the standard intramuscular dose, has been developed to more efficiently manage limited IPV supplies. fIPV has been shown in some studies to be noninferior to full-dose IPV (5,6) and was used successfully in response to a similar detection of a single VDPV2 isolate from sewage in India (7). Injectable fIPV was used for response activities in Hyderabad and three neighboring districts. This report describes the findings of an assessment of preparatory activities and subsequent implementation of the fIPV campaign. Despite achieving high coverage (>80%), several operational challenges were noted. The lessons learned from this campaign could help to guide the planning and implementation of future fIPV vaccination activities.

Progress Toward Poliomyelitis Eradication - Pakistan, January 2016-September 2017.

In 1988, the World Health Assembly launched the Global Polio Eradication Initiative. Among the three wild poliovirus serotypes, only wild poliovirus (WPV) type 1 (WPV1) has been detected since 2012. Since 2014, Pakistan, Afghanistan, and Nigeria remain the only countries with continuing endemic WPV1 transmission. This report describes activities conducted and progress made toward the eradication of poliovirus in Pakistan during January 2016-July 2017 and provides an update to previous reports (1,2). In 2016, Pakistan reported 20 WPV1 cases, a 63% decrease compared with 54 cases in 2015 (3). As of September 25, 2017, five WPV1 cases have been reported in 2017, representing a 69% decline compared with 16 cases reported during the same period in 2016 (Figure 1). During January-September 2017, WPV1 was detected in 72 of 468 (15%) environmental samples collected, compared with 36 of 348 (9%) samples collected during the same period in 2016. WPV1 was detected in environmental samples in areas where no polio cases are being reported, which indicates that WPV1 transmission is continuing in some high-risk areas. Interruption of WPV transmission in Pakistan requires maintaining focus on reaching missed children (particularly among mobile populations), continuing community-based vaccination, implementing the 2017-2018 National Emergency Action Plan (4), and improving routine immunization services.

Routine Immunization Service Delivery Through the Basic Package of Health Services Program in Afghanistan: Gaps, Challenges, and Opportunities.

Background: The Basic Package of Health Services (BPHS) program has increased access to immunization services for children living in rural Afghanistan. However, multiple surveys have indicated persistent immunization coverage gaps. Hence, to identify gaps in implementation, an assessment of the BPHS program was undertaken, with specific focus on the routine immunization (RI) component. Methods: A cross-sectional survey was conducted in 2014 on a representative sample drawn from a sampling frame of 1858 BPHS health facilities. Basic descriptive analysis was performed, capturing general characteristics of survey respondents and assessing specific RI components, and χ2 tests were used to evaluate possible differences in service delivery by type of health facility. Results: Of 447 survey respondents, 27% were health subcenters (HSCs), 30% were basic health centers, 32% were comprehensive health centers, and 12% were district hospitals. Eighty-seven percent of all respondents offered RI services, though only 61% of HSCs did so. Compared with other facility types, HSCs were less likely to have adequate stock of vaccines, essential cold-chain equipment, or proper documentation of vaccination activities. Conclusions: There is an urgent need to address manpower and infrastructural deficits in RI service delivery through the BPHS program, especially at the HSC level.

Progress Toward Poliomyelitis Eradication - Afghanistan, January 2016-June 2017.

Afghanistan, Pakistan, and Nigeria remain the only countries where the transmission of endemic wild poliovirus type 1 (WPV1) continues (1). This report describes polio eradication activities, progress, and challenges in Afghanistan during January 2016-June 2017 and updates previous reports (2,3). Thirteen WPV1 cases were confirmed in Afghanistan in 2016, a decrease of seven from the 20 cases reported in 2015. From January to June 2017, five WPV1 cases were reported, compared with six during the same period in 2016. The number of affected districts declined from 23 (including WPV1-positive acute flaccid paralysis [AFP] cases and positive environmental sewage samples) in 2015 to six in 2016. To achieve WPV1 eradication, it is important that Afghanistan's polio program continue to collaborate with that of neighboring Pakistan to track and vaccinate groups of high-risk mobile populations and strengthen efforts to reach children in security-compromised areas.

Response to a Large Polio Outbreak in a Setting of Conflict - Middle East, 2013-2015.

As the world advances toward the eradication of polio, outbreaks of wild poliovirus (WPV) in polio-free regions pose a substantial risk to the timeline for global eradication. Countries and regions experiencing active conflict, chronic insecurity, and large-scale displacement of persons are particularly vulnerable to outbreaks because of the disruption of health care and immunization services (1). A polio outbreak occurred in the Middle East, beginning in Syria in 2013 with subsequent spread to Iraq (2). The outbreak occurred 2 years after the onset of the Syrian civil war, resulted in 38 cases, and was the first time WPV was detected in Syria in approximately a decade (3,4). The national governments of eight countries designated the outbreak a public health emergency and collaborated with partners in the Global Polio Eradication Initiative (GPEI) to develop a multiphase outbreak response plan focused on improving the quality of acute flaccid paralysis (AFP) surveillance* and administering polio vaccines to >27 million children during multiple rounds of supplementary immunization activities (SIAs).† Successful implementation of the response plan led to containment and interruption of the outbreak within 6 months of its identification. The concerted approach adopted in response to this outbreak could serve as a model for responding to polio outbreaks in settings of conflict and political instability.

Progress Toward Poliomyelitis Eradication - Afghanistan, January 2015‒August 2016.

Only 74 cases of wild poliovirus (WPV) were reported globally in 2015, the lowest number of cases ever reported worldwide (1,2). All of the reported cases were WPV type 1 (WPV1), the only known WPV type still circulating; WPV type 2 has been eradicated, and WPV type 3 has not been detected since November 2012 (1). In 2015 in Afghanistan, WPV detection also declined from 2014, and trends observed in 2016 suggest that circulation of the virus is limited to a few localized areas. Despite the progress, there are concerns about the ability of the country's Polio Eradication Initiative (PEI) to meet the goal of interrupting endemic WPV transmission by the end of 2016 (3). The deteriorating security situation in the Eastern and Northeastern regions of the country considerably limits the ability to reach and vaccinate children in these regions. Furthermore, because of frequent population movements to and from Pakistan, cross-border transmission of WPV1 continues (4). Although the national PEI has taken steps to improve the quality of supplementary immunization activities (SIAs),* significant numbers of children living in accessible areas are still being missed during SIAs, and routine immunization services remain suboptimal in many parts of the country. This report describes polio eradication activities and progress in Afghanistan during January 2015‒August 2016 and updates previous reports (5,6). During 2015, a total of 20 WPV1 cases were reported in Afghanistan, compared with 28 cases in 2014; eight cases were reported during January‒August 2016, compared with nine cases reported during the same period in 2015. To achieve interruption of poliovirus transmission in Afghanistan, it is important that the 2016-2017 National Emergency Action Plan† for polio eradication be systematically implemented, including 1) improving the quality of SIAs and routine immunization services, 2) ensuring ongoing dialogue between PEI leaders and local authorities, 3) adopting innovative strategies for reaching children in security-compromised and inaccessible areas, and 4) strengthening cross-border coordination of polio vaccination and surveillance activities with Pakistan.

Contribution of Contact Sampling in Increasing Sensitivity of Poliovirus Detection During A Polio Outbreak-Somalia, 2013.

Background. In May 2013, a wild poliovirus type 1 (WPV1) outbreak reported in Somalia provided an opportunity to examine the contribution of testing contacts to WPV detection. Methods. We reviewed acute flaccid paralysis (AFP) case-patients and linked contacts reported in the Somalia Surveillance Database from May 9 to December 31, 2013. We restricted our analysis to AFP case-patients that had ≥3 contacts and calculated the contribution of each contact to case detection. Results. Among 546 AFP cases identified, 328 AFP cases had ≥3 contacts. Among the 328 AFP cases with ≥3 contacts, 93 WPV1 cases were detected: 58 cases (62%; 95% confidence interval [CI], 52%-72%) were detected through testing stool specimens from AFP case-patients; and 35 cases (38%; 95% CI, 28%-48%) were detected through testing stool specimens from contacts, including 19 cases (20%; 95% CI, 14%-30%) from the first contact, 11 cases (12%; 95% CI, 7%-20%) from the second contact, and 5 cases (5%; 95% CI, 2%-12%) from the third contact. Among the 103 AFP cases with ≥4 contacts, 3 (6%; 95% CI, 2%-16%) of 52 WPV1 cases were detected by testing the fourth contact. No additional WPV1 cases were detected by testing >4 contacts. Conclusions. Stool specimens from 3 to 4 contacts of persons with AFP during polio outbreaks are needed to maximize detection of WPV cases.

Transmission of Balamuthia mandrillaris by Organ Transplantation.

BACKGROUND: During 2009 and 2010, 2 clusters of organ transplant-transmitted Balamuthia mandrillaris, a free-living ameba, were detected by recognition of severe unexpected illness in multiple recipients from the same donor. METHODS: We investigated all recipients and the 2 donors through interview, medical record review, and testing of available specimens retrospectively. Surviving recipients were tested and treated prospectively. RESULTS: In the 2009 cluster of illness, 2 kidney recipients were infected and 1 died. The donor had Balamuthia encephalitis confirmed on autopsy. In the 2010 cluster, the liver and kidney-pancreas recipients developed Balamuthia encephalitis and died. The donor had a clinical syndrome consistent with Balamuthia infection and serologic evidence of infection. In both clusters, the 2 asymptomatic recipients were treated expectantly and survived; 1 asymptomatic recipient in each cluster had serologic evidence of exposure that decreased over time. Both donors had been presumptively diagnosed with other neurologic diseases prior to organ procurement. CONCLUSIONS: Balamuthia can be transmitted through organ transplantation with an observed incubation time of 17-24 days. Clinicians should be aware of Balamuthia as a cause of encephalitis with high rate of fatality, and should notify public health departments and evaluate transplant recipients from donors with signs of possible encephalitis to facilitate early diagnosis and targeted treatment. Organ procurement organizations and transplant centers should be aware of the potential for Balamuthia infection in donors with possible encephalitis and also assess donors carefully for signs of neurologic infection that may have been misdiagnosed as stroke or as noninfectious forms of encephalitis.