Dogs on the move: Estimating the risk of rabies in imported dogs in the United States, 2015-2022.

BACKGROUND: Dog-mediated rabies virus variant (DMRVV), a zoonotic pathogen that causes a deadly disease in animals and humans, is present in more than 100 countries worldwide but has been eliminated from the United States since 2007. In the United States, the U.S. Centers for Disease Control and Prevention has recorded four instances of rabies in dogs imported from DMRVV-enzootic countries since 2015. However, it remains uncertain whether the incidence of DMRVV among imported dogs from these countries significantly surpasses that of domestically acquired variants among domestic U.S. dogs. AIM: This evaluation aimed to estimate the number of dogs imported from DMRVV-enzootic countries and compare the risk of rabies between imported dogs and the U.S. domestic dog population. MATERIALS AND METHODS: Data from the CDC's dog import permit system (implemented during 2021 under a temporary suspension of dog importation from DMRVV-enzootic countries) and U.S. Customs and Border Protection's Automated Commercial Environment system, each of which records a segment of dogs entering the U.S. from DMRVV-enzootic countries, was analysed. Additionally, we estimated the incidence rate of rabies in dogs imported from DMRVV-enzootic countries and compared it to the incidence rate within the general U.S. dog population, due to domestically acquired rabies variants, over the eight-year period (2015-2022). RESULTS: An estimated 72,589 (range, 62,660-86,258) dogs were imported into the United States annually between 2015 and 2022 from DMRVV-enzootic countries. The estimated incidence rate of rabies was 16 times higher (range, 13.2-19.4) in dogs imported from DMRVV-enzootic countries than that estimated for domestically acquired rabies in the general U.S. dog population. CONCLUSIONS: Preventing human exposure to dogs with DMRVV is a public health priority. The higher risk of rabies in dogs imported from DMRVV-enzootic countries supports the need for importation requirements aimed at preventing the reintroduction of DMRVV into the United States.

Human exposures to Brucella canis from a pregnant dog during an international flight: Public health risks, diagnostic challenges and future considerations.

AIMS: This report documents the exposure of passengers and crew of a commercial international flight to the zoonotic pathogen Brucella canis after an infected dog aborted in the passenger cabin of the aircraft. This case demonstrates the challenges associated with brucellosis screening and the risks that airline personnel, airport employees and travellers face when animals with unrecognized zoonotic infections are transported. METHODS/RESULTS: The public health investigation of this case was conducted by the Centers for Disease Control, the Illinois Department of Health and the Illinois Department of Agriculture, in collaboration with a local veterinary clinic and several academic and federal diagnostic laboratories. It included an extensive diagnostic evaluation of the dam and aborted foetuses to confirm a diagnosis of canine brucellosis. Passengers, airline personnel and staff from the veterinary clinic where the dogs were treated underwent risk assessments, and clinic staff also received detailed guidance regarding infection prevention practices. CONCLUSIONS: Animal shelters and breeding programs are recommended to screen dogs routinely for brucellosis, but it is not unusual for domestic or imported animals to have unknown health histories, including the dog's brucellosis status, at the time of purchase, adoption, or re-homing. Testing recommendations and requirements vary by state, making it challenging for state public health and animal health agencies to monitor and respond appropriately. This case highlights the importance of Brucella spp. screening in sexually intact dogs prior to breeding, purchase, or domestic or international transportation of the dogs. The transportation of pregnant dogs may present a previously unrecognized public health threat in addition to contributing to unnecessary stress and health risks for pregnant animals.

Outbreak of Mycobacterium orygis in a Shipment of Cynomolgus Macaques Imported from Southeast Asia - United States, February-May 2023.

Nonhuman primates (NHP) can become infected with the same species of Mycobacteria that cause human tuberculosis. All NHP imported into the United States are quarantined and screened for tuberculosis; no confirmed cases of tuberculosis were diagnosed among NHP during CDC-mandated quarantine during 2013-2020. In February 2023, an outbreak of tuberculosis caused by Mycobacterium orygis was detected in a group of 540 cynomolgus macaques (Macaca fascicularis) imported to the United States from Southeast Asia for research purposes. Although the initial exposure to M. orygis is believed to have occurred before the macaques arrived in the United States, infected macaques were first detected during CDC-mandated quarantine. CDC collaborated with the importer and U.S. Department of Agriculture's National Veterinary Services Laboratories in the investigation and public health response. A total of 26 macaques received positive test results for M. orygis by culture, but rigorous occupational safety protocols implemented during transport and at the quarantine facility prevented cases among caretakers in the United States. Although the zoonotic disease risk to the general population remains low, this outbreak underscores the importance of CDC's regulatory oversight of NHP importation and adherence to established biosafety protocols to protect the health of the United States research animal population and the persons who interact with them.

Demographic and travel characteristics and self-reported predeparture SARS-CoV-2 testing behavior in air passengers entering the United States from foreign destinations from July to September 2021.

INTRODUCTION: From January 2021 to June 2022, the United States Centers for Disease Control and Prevention required predeparture SARS-CoV-2 testing for all air passengers arriving into the United States from a foreign country. METHODS: Using data collected during a surveillance project, we described predeparture testing behavior among a convenience sample of international air passengers entering the United States from July to September 2021 at six US ports of entry. We analyzed pairwise relationships between self-reported test type, test timing, demographic and travel characteristics, and COVID-19 vaccination status using chi-square and Fisher's exact tests. RESULTS: Participants were more likely to get a NAAT versus antigen test if they identified as non-Hispanic Asian or Pacific Islander (68.2%, n = 173), non-Hispanic Black (62.6%, n = 147), or if they preferred not to report race and ethnicity (60.8%, n = 209) when compared to those who identified as non-Hispanic White (47.1%, n = 1086, all p < 0.05). Those who identified as Hispanic or Latino (n = 671) were less likely to get a NAAT than the non-Hispanic White group (39.5% vs. 47.1%, p < 0.05). Participants arriving in the US from the Americas were less likely to get a NAAT (38.5%, n = 871) compared to those arriving from Europe (45.5%, n = 1165, p < 0.05). Participants who reported receiving their predeparture test 2 days or 3 or more days before departure were more likely to report receiving a NAAT (52.2%, n = 879, and 60.2%, n = 410, respectively) than those who reported testing within 1 day (41.4%, n = 1040, all p < 0.001) of departure. DISCUSSION: Test type was significantly associated with race and ethnicity, departure region, and test timing. Differences likely reflected regional disparities in the availability of tests at the time of the activity. Discrepancies in predeparture test timing and type worldwide may have consequences for the effectiveness and equity of travel requirements in future pandemics.

SARS-CoV-2 Cases Reported on International Arriving and Domestic Flights: United States, January 2020-December 2021.

Objectives. To describe trends in the number of air travelers categorized as infectious with SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2; the virus that causes COVID-19) in the context of total US COVID-19 vaccinations administered, and overall case counts of SARS-CoV-2 in the United States. Methods. We searched the Quarantine Activity Reporting System (QARS) database for travelers with inbound international or domestic air travel, a positive SARS-CoV-2 lab result, and a surveillance categorization of SARS-CoV-2 infection reported during January 2020 to December 2021. Travelers were categorized as infectious during travel if they had arrival dates from 2 days before to 10 days after symptom onset or a positive viral test. Results. We identified 80 715 persons meeting our inclusion criteria; 67 445 persons (83.6%) had at least 1 symptom reported. Of 67 445 symptomatic passengers, 43 884 (65.1%) reported an initial symptom onset date after their flight arrival date. The number of infectious travelers mirrored the overall number of US SARS-CoV-2 cases. Conclusions. Most travelers in the study were asymptomatic during travel, and therefore unknowingly traveled while infectious. During periods of high community transmission, it is important for travelers to stay up to date with COVID-19 vaccinations and consider wearing a high-quality mask to decrease the risk of transmission. (Am J Public Health. 2023;113(8):904-908. https://doi.org/10.2105/AJPH.2023.307325).

COVID-19 on the Nile: a cross-sectional investigation of COVID-19 among Nile River cruise travellers returning to the United States, February-March 2020.

BACKGROUND: Early in the pandemic, cruise travel exacerbated the global spread of SARS-CoV-2. We report epidemiologic and molecular findings from an investigation of a cluster of travellers with confirmed COVID-19 returning to the USA from Nile River cruises in Egypt. METHODS: State health departments reported data on real-time reverse transcription-polymerase chain reaction-confirmed COVID-19 cases with a history of Nile River cruise travel during February-March 2020 to the Centers for Disease Control and Prevention (CDC). Demographic and epidemiologic data were collected through routine surveillance channels. Sequences were obtained either from state health departments or from the Global Initiative on Sharing Avian Flu Data (GISAID). We conducted descriptive analyses of epidemiologic data and explored phylogenetic relationships between sequences. RESULTS: We identified 149 Nile River cruise travellers with confirmed COVID-19 who returned to 67 different US counties in 27 states: among those with complete data, 4.7% (6/128) died and 28.1% (38/135) were hospitalized. These individuals travelled on 20 different Nile River cruise voyages (12 unique vessels). Fifteen community transmission events were identified in four states, with 73.3% (11/15) of these occurring in Wisconsin (as the result of a more detailed contact investigation in that state). Phylogenetic analyses supported the hypothesis that travellers were most likely infected in Egypt, with most sequences in Nextstrain clade 20A 93% (87/94). We observed genetic clustering by Nile River cruise voyage and vessel. CONCLUSIONS: Nile River cruise travellers with COVID-19 introduced SARS-CoV-2 over a very large geographic range, facilitating transmission across the USA early in the pandemic. Travellers who participate in cruises, even on small river vessels as investigated in this study, are at increased risk of SARS-CoV-2 exposure. Therefore, history of river cruise travel should be considered in contact tracing and outbreak investigations.

Review of CDC's Suspension of and Advance Written Approval Process for Dogs Entering the United States from Egypt - May 2019-December 2020.

Dog-maintained rabies virus variant (DMRVV) was eliminated in the United States in 2007. During 2015­2019, three dogs with rabies were imported into the United States from Egypt, where DMRVV is endemic. CDC developed a risk mitigation strategy, in consultation with a diverse group of subject matter experts, that permitted 296 dogs to be imported from Egypt during May 10, 2019­December 31, 2020, minimizing the risk for future rabid dog importations. The broadly vetted risk mitigation strategy, which included serologic testing for rabies antibody titer, improved CDC's ability to ensure that imported dogs from Egypt posed no public health risk in the United States. This strategy could be used to guide future policy decisions regarding dog importations.

Rabies in a Dog Imported from Azerbaijan - Pennsylvania, 2021.

On June 16, 2021, rabies virus infection was confirmed in a dog included in a shipment of rescue animals imported into the United States from Azerbaijan. A multistate investigation was conducted to prevent secondary rabies cases, avoid reintroduction of a dog-maintained rabies virus variant (DMRVV), identify persons who might have been exposed and would be recommended to receive rabies postexposure prophylaxis, and investigate the cause of importation control failures. Results of a prospective serologic monitoring (PSM) protocol suggested that seven of 32 (22%) animals from the same shipment as the dog with confirmed rabies virus infection and who had available titer results after rabies vaccine booster had not been adequately vaccinated against rabies before importation. A requirement for rabies vaccination certificates alone will not adequately identify improper vaccination practices or fraudulent paperwork and are insufficient as a stand-alone rabies importation prevention measure. Serologic titers before importation would mitigate the risk for importing DMRVV.

A country classification system to inform rabies prevention guidelines and regulations.

BACKGROUND: Assessing the global risk of rabies exposure is a complicated task requiring individual risk assessments, knowledge of rabies epidemiology, surveillance capacity and accessibility of rabies biologics on a national and regional scale. In many parts of the world, availability of this information is limited and when available is often dispersed across multiple sources. This hinders the process of making evidence-based health and policy recommendations to prevent the introduction and spread of rabies. METHODS: CDC conducted a country-by-country qualitative assessment of risk and protective factors for rabies to develop an open-access database of core metrics consisting of the presence of lyssaviruses (specifically canine or wildlife rabies virus variants or other bat lyssaviruses), access to rabies immunoglobulins and vaccines, rabies surveillance capacity and canine rabies control capacity. Using these metrics, we developed separate risk scoring systems to inform rabies prevention guidance for travelers and regulations for the importation of dogs. Both scoring systems assigned higher risk to countries with enzootic rabies (particularly canine rabies), and the risk scoring system for travelers also considered protective factors such as the accessibility of rabies biologics for post-exposure prophylaxis. Cumulative scores were calculated across the assessed metrics to assign a risk value of low, moderate or high. RESULTS: A total of 240 countries, territories and dependencies were assessed, for travelers, 116 were identified as moderate to high risk and 124 were low or no risk; for canine rabies virus variant importation, 111 were identified as high-risk and 129 were low or no risk. CONCLUSIONS: We developed a comprehensive and easily accessible source of information for assessing the rabies risk for individual countries that included a database of rabies risk and protective factors based on enzootic status and availability of biologics, provided a resource that categorizes risk by country and provided guidance based on these risk categories for travelers and importers of dogs into the United States.

Cross-sectional survey of SARS-CoV-2 testing at US airports and one health department's proactive management of travelers.

BACKGROUND: Many health departments and private enterprises began offering SARS-CoV-2 testing to travelers at US airports in 2020. Persons with positive SARS-CoV-2 test results who have planned upcoming travel may be subject to US federal public health travel restrictions. We assessed availability of testing for SARS-CoV-2 at major US airports. We then describe the management of cases and close contacts at Denver International Airport's testing site. METHODS: We selected 100 US airports. Online surveys were conducted during November-December 2020 and assessed availability of testing for air travelers, flight crew, and airport employees. Respondents included health department (HD) staff or airport directors. We analyzed testing data and management practices for persons who tested positive and their close contacts at one airport (Denver International) from 12/21/2020 to 3/31/2021. RESULTS: Among the 100 selected airports, we received information on 77 airports; 38 (49%) had a testing site and several more planned to offer one (N = 7; 9%). Most sites began testing in the fall of 2020. The most frequently offered tests were RT-PCR or other NAAT tests (N = 28). Denver International Airport offered voluntary SARS-CoV-2 testing. Fifty-four people had positive results among 5724 tests conducted from 12/21/2020 to 3/31/2021 for a total positivity of < 1%. Of these, 15 were travelers with imminent flights. The Denver HD issued an order requiring the testing site to immediately report cases and notify airlines to cancel upcoming flight itineraries for infected travelers and their traveling close contacts, minimizing the use of federal travel restrictions. CONCLUSIONS: As of December 2020, nearly half of surveyed US airports had SARS-CoV-2 testing sites. Such large-scale adoption of airport testing for a communicable disease is unprecedented and presents new challenges for travelers, airlines, airports, and public health authorities. This assessment was completed before the US and other countries began enforcing entry testing requirements; testing at airports will likely increase as travel demand returns and test requirements for travel evolve. Lessons from Denver demonstrate how HDs can play a key role in engaging airport testing sites to ensure people who test positive for SARS-CoV-2 immediately before travel do not travel on commercial aircraft.

Risk factors for death and illness in dogs imported into the United States, 2010-2018.

CDC estimates 1 million dogs are imported into the United States annually. With the movement of large numbers of animals into the United States the risk of disease importation, especially emerging diseases, and animal welfare issues are of concern. Dogs that arrive to the United States ill or dead are investigated by public health authorities to ensure dogs are not infected with diseases of concern (such as rabies). We identified factors associated with illness and death in imported dogs and estimated the initial investigation cost to public health authorities. Dog importation data from the CDC's Quarantine Activity Reporting System were reviewed from 2010 to 2018. The date of entry, country of origin, port of entry, transportation method and breed were extracted to examine factors associated with illness and death in dogs during international travel. Costs for public health investigations were estimated from data collected by the Bureau of Labor Statistics and Office of Personal Management. Death or illness was more likely to occur in brachycephalic breeds (aOR = 3.88, 95%CI 2.74-5.51). Transportation of dogs via cargo (aOR = 2.41, 95%CI 1.57-3.70) or as checked baggage (aOR = 5.74, 95%CI 3.65-9.03) were also associated with death or illness. On average, 19 dog illnesses or deaths were reported annually from 2010 to 2018. The estimated annual cost to public health authorities to conduct initial public health assessments ranged from $2,071 to $104,648. Current regulations do not provide adequate resources or mechanisms to monitor the rates of morbidity and mortality of imported dogs. There are growing attempts to assess animal welfare and communicable disease importation risks. However, because the responsibility for dogs' health and wellbeing is overseen by multiple agencies it is challenging to coordinate implementation and enforcement measures. A joint federal agency approach to identify interventions that reduce dog morbidity and mortality during flights while continuing to protect US borders from public health and foreign animal disease threats could be beneficial.

Cruise Ship Travel in the Era of Coronavirus Disease 2019 (COVID-19): A Summary of Outbreaks and a Model of Public Health Interventions.

BACKGROUND: Cruise travel contributed to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission when there were relatively few cases in the United States. By 14 March 2020, the Centers for Disease Control and Prevention (CDC) issued a No Sail Order suspending US cruise operations; the last US passenger ship docked on 16 April. METHODS: We analyzed SARS-CoV-2 outbreaks on cruises in US waters or carrying US citizens and used regression models to compare voyage characteristics. We used compartmental models to simulate the potential impact of 4 interventions (screening for coronavirus disease 2019 (COVID-19) symptoms; viral testing on 2 days and isolation of positive persons; reduction of passengers by 40%, crew by 20%, and reducing port visits to 1) for 7-day and 14-day voyages. RESULTS: During 19 January to 16 April 2020, 89 voyages on 70 ships had known SARS-CoV-2 outbreaks; 16 ships had recurrent outbreaks. There were 1669 reverse transcription polymerase chain reaction (RT-PCR)-confirmed SARS-CoV-2 infections and 29 confirmed deaths. Longer voyages were associated with more cases (adjusted incidence rate ratio, 1.10, 95% confidence interval [CI]: 1.03-1.17, P < .003). Mathematical models showed that 7-day voyages had about 70% fewer cases than 14-day voyages. On 7-day voyages, the most effective interventions were reducing the number of individuals onboard (43.3% reduction in total infections) and testing passengers and crew (42% reduction in total infections). All four interventions reduced transmission by 80.1%, but no single intervention or combination eliminated transmission. Results were similar for 14-day voyages. CONCLUSIONS: SARS-CoV-2 outbreaks on cruises were common during January-April 2020. Despite all interventions modeled, cruise travel still poses a significant SARS-CoV-2 transmission risk.

Melioidosis in Cynomolgus Macaques ( Macaca Fascicularis ) Imported to the United States from Cambodia.

Melioidosis, a potentially fatal infectious disease of humans and animals, including nonhuman primates (NHPs), is caused by the high-consequence pathogen Burkholderia pseudomallei. This environmental bacterium is found in the soil and water of tropical regions, such as Southeast Asia, where melioidosis is endemic. The global movement of humans and animals can introduce B. pseudomallei into nonendemic regions of the United States, where environmental conditions could allow establishment of the organism. Approximately 60% of NHPs imported into the United States originate in countries considered endemic for melioidosis. To prevent the introduction of infectious agents to the United States, the Centers for Disease Control and Prevention (CDC) requires newly imported NHPs to be quarantined for at least 31 d, during which time their health is closely monitored. Most diseases of public health concern that are transmissible from imported NHPs have relatively short incubation periods that fall within the 31-d quarantine period. However, animals infected with B. pseudomallei may appear healthy for months to years before showing signs of illness, during which time they can shed the organism into the environment. Melioidosis presents diagnostic challenges because it causes nonspecific clinical signs, serologic screening can produce unreliable results, and culture isolates are often misidentified on rapid commercial testing systems. Here, we present a case of melioidosis in a cynomolgus macaque (Macaca fascicularis) that developed a subcutaneous abscess after importation from Cambodia to the United States. The bacterial isolate from the abscess was initially misidentified on a commercial test. This case emphasizes the possibility of melioidosis in NHPs imported from endemic countries and its associated diagnostic challenges. If melioidosis is suspected, diagnostic samples and culture isolates should be submitted to a laboratory in the CDC Laboratory Response Network for conclusive identification and characterization of the pathogen.

U.S. dog importations during the COVID-19 pandemic: Do we have an erupting problem?

Dog importation data from 2018-2020 were evaluated to ascertain whether the dog importation patterns in the United States changed during the COVID-19 pandemic, specifically with regard to denial of entry. Dog denial of entry reports from January 1, 2018, to December 31, 2020, stored within the Centers for Disease Control and Prevention (CDC) Quarantine Activity Reporting System (QARS), were reviewed. Basic descriptive statistics were used to analyze the data. Reason for denial, country of origin, and month of importation were all examined to determine which countries of origin resulted in the largest number of denials, and whether there was a seasonal change in importations during the COVID-19 pandemic (2020), compared to previous years (2018 and 2019). During 2020, CDC denied entry to 458 dogs. This represents a 52% increase in dogs denied entry compared to the averages in 2018 and 2019. Dogs were primarily denied entry for falsified rabies vaccination certificates (56%). Three countries exported 74% of all dogs denied entry into the United States, suggesting that targeted interventions may be needed for certain countries. Increased attempts to import inadequately vaccinated dogs from countries with canine rabies in 2020 may have been due to the increased demand for domestic pets during the COVID-19 pandemic. Educational messaging should highlight the risk of rabies and the importance of making informed pet purchases from foreign entities to protect pet owners, their families, and the public.

Reducing travel-related SARS-CoV-2 transmission with layered mitigation measures: symptom monitoring, quarantine, and testing.

BACKGROUND: Balancing the control of SARS-CoV-2 transmission with the resumption of travel is a global priority. Current recommendations include mitigation measures before, during, and after travel. Pre- and post-travel strategies including symptom monitoring, antigen or nucleic acid amplification testing, and quarantine can be combined in multiple ways considering different trade-offs in feasibility, adherence, effectiveness, cost, and adverse consequences. METHODS: We used a mathematical model to analyze the expected effectiveness of symptom monitoring, testing, and quarantine under different estimates of the infectious period, test-positivity relative to time of infection, and test sensitivity to reduce the risk of transmission from infected travelers during and after travel. RESULTS: If infection occurs 0-7 days prior to travel, immediate isolation following symptom onset prior to or during travel reduces risk of transmission while traveling by 30-35%. Pre-departure testing can further reduce risk, with testing closer to the time of travel being optimal even if test sensitivity is lower than an earlier test. For example, testing on the day of departure can reduce risk while traveling by 44-72%. For transmission risk after travel with infection time up to 7 days prior to arrival at the destination, isolation based on symptom monitoring reduced introduction risk at the destination by 42-56%. A 14-day quarantine after arrival, without symptom monitoring or testing, can reduce post-travel risk by 96-100% on its own. However, a shorter quarantine of 7 days combined with symptom monitoring and a test on day 5-6 after arrival is also effective (97--100%) at reducing introduction risk and is less burdensome, which may improve adherence. CONCLUSIONS: Quarantine is an effective measure to reduce SARS-CoV-2 transmission risk from travelers and can be enhanced by the addition of symptom monitoring and testing. Optimal test timing depends on the effectiveness of quarantine: with low adherence or no quarantine, optimal test timing is close to the time of arrival; with effective quarantine, testing a few days later optimizes sensitivity to detect those infected immediately before or while traveling. These measures can complement recommendations such as social distancing, using masks, and hand hygiene, to further reduce risk during and after travel.

Use of US Public Health Travel Restrictions during COVID-19 Outbreak on Diamond Princess Ship, Japan, February-April 2020.

Public health travel restrictions (PHTR) are crucial measures during communicable disease outbreaks to prevent transmission during commercial airline travel and mitigate cross-border importation and spread. We evaluated PHTR implementation for US citizens on the Diamond Princess during its coronavirus disease (COVID-19) outbreak in Japan in February 2020 to explore how PHTR reduced importation of COVID-19 to the United States during the early phase of disease containment. Using PHTR required substantial collaboration among the US Centers for Disease Control and Prevention, other US government agencies, the cruise line, and public health authorities in Japan. Original US PHTR removal criteria were modified to reflect international testing protocols and enable removal of PHTR for persons who recovered from illness. The impact of PHTR on epidemic trajectory depends on the risk for transmission during travel and geographic spread of disease. Lessons learned from the Diamond Princess outbreak provide critical information for future PHTR use.

Risk Assessment and Management of COVID-19 Among Travelers Arriving at Designated U.S. Airports, January 17-September 13, 2020.

In January 2020, with support from the U.S. Department of Homeland Security (DHS), CDC instituted an enhanced entry risk assessment and management (screening) program for air passengers arriving from certain countries with widespread, sustained transmission of SARS-CoV-2, the virus that causes coronavirus disease 2019 (COVID-19). The objectives of the screening program were to reduce the importation of COVID-19 cases into the United States and slow subsequent spread within states. Screening aimed to identify travelers with COVID-19-like illness or who had a known exposure to a person with COVID-19 and separate them from others. Screening also aimed to inform all screened travelers about self-monitoring and other recommendations to prevent disease spread and obtain their contact information to share with public health authorities in destination states. CDC delegated postarrival management of crew members to airline occupational health programs by issuing joint guidance with the Federal Aviation Administration.* During January 17-September 13, 2020, a total of 766,044 travelers were screened, 298 (0.04%) of whom met criteria for public health assessment; 35 (0.005%) were tested for SARS-CoV-2, and nine (0.001%) had a positive test result. CDC shared contact information with states for approximately 68% of screened travelers because of data collection challenges and some states' opting out of receiving data. The low case detection rate of this resource-intensive program highlighted the need for fundamental change in the U.S. border health strategy. Because SARS-CoV-2 infection and transmission can occur in the absence of symptoms and because the symptoms of COVID-19 are nonspecific, symptom-based screening programs are ineffective for case detection. Since the screening program ended on September 14, 2020, efforts to reduce COVID-19 importation have focused on enhancing communications with travelers to promote recommended preventive measures, reinforcing mechanisms to refer overtly ill travelers to CDC, and enhancing public health response capacity at ports of entry. More efficient collection of contact information for international air passengers before arrival and real-time transfer of data to U.S. health departments would facilitate timely postarrival public health management, including contact tracing, when indicated. Incorporating health attestations, predeparture and postarrival testing, and a period of limited movement after higher-risk travel, might reduce risk for transmission during travel and translocation of SARS-CoV-2 between geographic areas and help guide more individualized postarrival recommendations.

Severe Acute Respiratory Syndrome Coronavirus 2 Prevalence, Seroprevalence, and Exposure among Evacuees from Wuhan, China, 2020.

To determine prevalence of, seroprevalence of, and potential exposure to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) among a cohort of evacuees returning to the United States from Wuhan, China, in January 2020, we conducted a cross-sectional study of quarantined evacuees from 1 repatriation flight. Overall, 193 of 195 evacuees completed exposure surveys and submitted upper respiratory or serum specimens or both at arrival in the United States. Nearly all evacuees had taken preventive measures to limit potential exposure while in Wuhan, and none had detectable SARS-CoV-2 in upper respiratory tract specimens, suggesting the absence of asymptomatic respiratory shedding among this group at the time of testing. Evidence of antibodies to SARS-CoV-2 was detected in 1 evacuee, who reported experiencing no symptoms or high-risk exposures in the previous 2 months. These findings demonstrated that this group of evacuees posed a low risk of introducing SARS-CoV-2 to the United States.

The Cost and Public Health System Effects of Active Monitoring and Illness Response for Ebola Virus Disease: A Case Evaluation of Georgia.

In August 2014, the World Health Organization declared the Ebola virus disease epidemic in West Africa a public health emergency of international concern. After 2 imported cases of the disease were identified in the United States in autumn 2014, the Centers for Disease Control and Prevention recommended that all jurisdictions begin active monitoring of travelers at risk of developing Ebola virus disease for 21 days from the last day of a potential exposure to minimize the risk of disease transmission. Here we describe the infrastructure development, monitoring processes, total planned expenditures, and effects on the public health system in Georgia associated with active monitoring and illness response of all travelers from Ebola-affected West African countries from October 2014 to March 2016. We conducted qualitative interviews with Georgia Department of Public Health (GDPH) staff. We identified state active monitoring and illness response infrastructure investments and monitoring activities and state and federal funds spent in both areas. And, we evaluated whether active monitoring and illness response enhanced Georgia's ability to respond to future infectious disease outbreaks. Developing the infrastructure to support the monitoring and response required investment in information technology, training of public health and medical personnel, increasing laboratory capacity, and securing personal protective equipment. Estimated total expenditures were $8.25 million, with 76% spent on infrastructure and 17% on daily monitoring. The GDPH leveraged internal resources and partnerships to implement active monitoring and illness response. Infrastructure investment increased surveillance capacity, strengthened relationships between the GDPH and medical providers, and led to the creation of infectious disease transport and hospital networks. Active monitoring and illness response increased outbreak preparedness, but it warrants comparison with other possible responses to determine its overall value.

Public Health Responses to COVID-19 Outbreaks on Cruise Ships - Worldwide, February-March 2020.

An estimated 30 million passengers are transported on 272 cruise ships worldwide each year* (1). Cruise ships bring diverse populations into proximity for many days, facilitating transmission of respiratory illness (2). SARS-CoV-2, the virus that causes coronavirus disease (COVID-19) was first identified in Wuhan, China, in December 2019 and has since spread worldwide to at least 187 countries and territories. Widespread COVID-19 transmission on cruise ships has been reported as well (3). Passengers on certain cruise ship voyages might be aged ≥65 years, which places them at greater risk for severe consequences of SARS-CoV-2 infection (4). During February-March 2020, COVID-19 outbreaks associated with three cruise ship voyages have caused more than 800 laboratory-confirmed cases among passengers and crew, including 10 deaths. Transmission occurred across multiple voyages of several ships. This report describes public health responses to COVID-19 outbreaks on these ships. COVID-19 on cruise ships poses a risk for rapid spread of disease, causing outbreaks in a vulnerable population, and aggressive efforts are required to contain spread. All persons should defer all cruise travel worldwide during the COVID-19 pandemic.