During the past three decades, since the 1988 World Health Assembly resolution to eradicate polio, the Global Polio Eradication Initiative (GPEI) efforts have decreased global polio incidence by 99.9%. GPEI efforts have benefitted over 16 million people who would otherwise have been paralysed, and approximately 1.5 million people whose lives would otherwise have been lost [1]. Now the task remains to tackle poliovirus transmission in its last few strongholds through parallel pursuits of wild poliovirus (WPV) eradication and vaccine-derived poliovirus (VDPV) transmission elimination [2,3]. There are 23 GPEI priority countries: 3 WPV-endemic (Afghanistan, Pakistan, Nigeria), 5 circulating VDPV (cVDPV) outbreak/active transmission, and 15 at-risk countries. Conflict, political instability, hard-to-reach populations, and poor infrastructure continue to pose challenges to eradicating the disease [2,3] (Photo 1). About half of all polio cases during 2009–2011 occurred due to international spread from endemic to polio-free countries [4]. In May 2014 the World Health Organization (WHO) declared the international spread of wild poliovirus as a Public Health Emergency of International Concern (PHEIC) per the IHR (2005) [4], and reiterated the concern during the 2018 the WHO IHR Emergency Committee meeting as the number of VDPV cases greatly exceeded the number of WPV cases in 2017 (96 vs. 22).

After the declaration of eradication of wild poliovirus type 2 in 2015, all countries using oral poliovirus vaccine (OPV) switched from using trivalent OPV (tOPV) (containing vaccine virus types 1, 2, and 3) to bivalent OPV (bOPV) (containing types 1 and 3) in April 2016 (1). Vaccine-derived polioviruses (VDPVs), strains that have diverged from the live vaccine virus during prolonged circulation, can emerge rarely in areas with inadequate OPV coverage and can cause outbreaks of paralysis. Before the global switch from tOPV to bOPV, many circulating VDPV (cVDPV) outbreaks identified globally were caused by type 2 cVDPV (cVDPV2). After the switch, two large cVDPV2 outbreaks occurred in 2017 in the Democratic Republic of the Congo (continuing in 2018) and Syria (2,3).

In the United States, Bacillus anthracis is a select agent and is subject to select agent requirements under the U.S. Code of Federal Regulations.* On April 20, 2015, samples of B. anthracis spores considered inactivated were shipped from a U.S. Department of Defense (DoD) laboratory at Dugway Proving Ground, Utah, to various laboratories for routine collaborative diagnostics research. On May 22, 2015, CDC was notified of live B. anthracis in one sample received by a private company and initiated a response. On May 29, 2015, DoD began reviewing safety practices for generating and handling inactivated B. anthracis spores. By June 1, 2015, the Office of the Assistant Secretary of Defense for Nuclear, Chemical, and Biological Defense Programs had established a task force to coordinate the DoD response (1). | The DoD Comprehensive Anthrax Laboratory Review (2) was completed within 30 days and addressed five main objectives: 1) conduct root cause analysis for incomplete inactivation of B. anthracis; 2) investigate the lack of effective postinactivation sterility testing for detection of live B. anthracis; 3) review DoD laboratory biohazard safety procedures/protocols; 4) determine laboratory adherence to established procedures/protocols; and 5) identify systemic problems and corresponding solutions. The DoD investigation identified 194 commercial companies, academic institutions, and federal laboratories that had received potentially live B. anthracis samples across 50 states, the District of Columbia, three U.S. territories, and nine foreign countries. | In South Korea, the Joint U.S. Forces Korea Portal and Integrated Threat Recognition program works on detection of biologic agents in the environment. A sample of B. anthracis was sent to Osan Air Base from the Dugway Proving Ground shipment for research, and 22 DoD personnel were exposed to the sample. Immediately after the event was discovered, these personnel were assessed for the need for emergency postexposure prophylaxis (PEP). On May 27, 2015, all 22 potentially exposed personnel began a PEP regimen tailored to their individual vaccination history. Persons lacking prior anthrax vaccination or with expired vaccination history received the standard emergency use protocol for PEP: 3 anthrax vaccine doses over 4 weeks plus 60 days of oral ciprofloxacin (500 mg twice a day) or doxycycline (100 mg twice a day) (3,4). Persons current for B. anthracis vaccination received emergency PEP: 30 days of oral ciprofloxacin or doxycycline (3,4) (Table).

Disease outbreaks of international public health importance continue to occur regularly; detecting and tracking significant new public health threats in countries that cannot or might not report such events to the global health community is a challenge. The Centers for Disease Control and Prevention's (CDC) Global Disease Detection (GDD) Operations Center, established in early 2007, monitors infectious and non-infectious public health events to identify new or unexplained global public health threats and better position CDC to respond, if public health assistance is requested or required. At any one time, the GDD Operations Center actively monitors approximately 30-40 such public health threats; here we provide our perspective on five of the top global infectious disease threats that we were watching in 2012: 1 avian influenza A (H5N1), 2 cholera, 3 wild poliovirus, 4 enterovirus-71, and 5 extensively drug-resistant tuberculosis.