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January 1996 - present
July 1994 - present
July 1992 - present
Publications
Publications (271)
Background
Over 1 million people traveled to Qatar and surrounding countries during the World Cup 2022 soccer tournament, a mass gathering that could enhance transmission of SARS-CoV-2 variants. Minimal information about circulating variants in World Health Organization (WHO) Eastern-Mediterranean region (EMRO) which includes Qatar, United Arab Emi...
In March 2021, Emergency Intake Sites (EIS) were created to address capacity shortfalls during a surge of Unaccompanied Children at the Mexico-United States land border. The COVID-19 Zone Plan (ZP) was developed to decrease COVID-19 transmission. COVID-19 cumulative percent (%) positivity was analyzed to evaluate the impact of the ZP, venue type an...
Beginning December 6, 2021, all international air passengers boarding flights to the United States were required to show either a negative result from a SARS-CoV-2 viral test taken ≤1 day before departure or proof of recovery from COVID-19 within the preceding 90 days (1). As of June 12, 2022, predeparture testing was no longer mandatory but remain...
Background
International travel facilitates SARS-CoV-2 spread globally. Early detection of variants among arriving international travelers could provide viral information about introduction of variants with differing infectivity, virulence, and vaccine effectiveness, enabling adjustments to treatment and prevention strategies. We initiated a genomi...
The Democratic Republic of the Congo's (DRC) 10th known Ebola virus disease (EVD) outbreak was the largest in the country's history and occurred from August 1, 2018 to June 25, 2020. During this outbreak, the DRC Ministry of Health initiated traveler health screening at points of control (POC, locations not on the border) and points of entry (POE)...
We enrolled arriving international air travelers in SARS-CoV-2 genomic surveillance, using molecular testing of pooled nasal swabs, and sequencing positive samples for viral sublineage. Traveler-based genomic surveillance provided early warning variant detection; we reported the first U.S. Omicron BA.2 and first BA.3 in North America, weeks before...
On August 29, 2021, the United States government oversaw the emergent establishment of Operation Allies Welcome (OAW), led by the U.S. Department of Homeland Security (DHS) and implemented by the U.S. Department of Defense (DoD) and U.S. Department of State (DoS), to safely resettle U.S. citizens and Afghan nationals from Afghanistan to the United...
We enrolled arriving international air travelers in SARS-CoV-2 genomic surveillance, using molecular testing of pooled nasal swabs, and sequencing positive samples for viral lineage. Traveler-based genomic surveillance provided early warning variant detection; we reported the first U.S. Omicron BA.2 and first BA.3 in North America, weeks before nex...
In February 2020, during the early days of the COVID-19 pandemic, 232 evacuees from Wuhan, China, were placed under federal 14-day quarantine upon arrival at a US military base in San Diego, California. We describe the monitoring of evacuees and responders for symptoms of COVID-19, case and contact investigations, infection control procedures, and...
Rationale:
Approximately two-thirds of new cases of tuberculosis (TB) in the United States are among non-U.S.-born persons. Culture-based overseas TB screening in U.S.-bound immigrants and refugees has substantially reduced the importation of TB into the United States, but it is unclear to what extent this program prevents the importation of multi...
Background
Cruise travel contributed to SARS-CoV-2 transmission when there were relatively few cases in the United States. By March 14, 2020, the Centers for Disease Control and Prevention (CDC) issued a No Sail Order suspending U.S. cruise operations; the last U.S. passenger ship docked on April 16.
Methods
We analyzed SARS-CoV-2 outbreaks on cru...
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...
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 Februar...
Air travel is an increasingly important conduit for the worldwide spread of infectious diseases. However, methods to identify which airports an individual may use to initiate travel, or where an individual may travel to upon arrival at an airport is not well studied. This knowledge gap can be addressed by estimating airport catchment areas: the geo...
Background
US-bound refugees undergo required health assessments overseas to identify and treat communicable diseases of public health significance—such as pulmonary tuberculosis—before migration. Immunizations are not required, leaving refugees at risk for vaccine-preventable diseases. In response, the US Centers for Disease Control and Prevention...
Background
While persons who receive immigrant and refugee visas are screened for active tuberculosis before admission into the United States, nonimmigrant visa applicants (NIVs) are not routinely screened and may enter the United States with infectious tuberculosis.
Objectives
We evaluated the costs and benefits of expanding pre-departure tubercu...
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, testing, and quarantine can be combined in multiple ways considering different trade-offs in feasibil...
These findings demonstrate that temperature and symptom screening at airports detected few COVID-19 cases and required considerable resources. The observed yield was approximately one identified case per 85,000 travelers screened. Reasons for the low yield were likely multifactorial and might have included an overall low COVID-19 prevalence in trav...
Background:
The Diamond Princess cruise ship was the site of a large outbreak of coronavirus disease 2019 (COVID-19). Of 437 Americans and their travel companions on the ship, 114 (26%) tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).
Methods:
We interviewed 229 American passengers and crew after disembarkation f...
Rationale:
U.S. health departments routinely conduct post-arrival evaluation of immigrants and refugees at risk for tuberculosis, but this important intervention has not been thoroughly studied.
Objectives:
To assess outcomes of the post-arrival evaluation intervention.
Methods:
We categorized at risk immigrants and refugees as: with recent co...
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 comp...
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 si...
The 2014-2016 Ebola epidemic in West Africa influenced how public health officials considered migration and emerging infectious diseases. Responding to the public’s concerns, the US government introduced enhanced entry screening and post-arrival monitoring by public health authorities to reduce the risk of importation and domestic transmission of E...
Migration and forced displacement are at record levels in today's geopolitical environment; ensuring the health of migrating populations and the health security of asylum and receiving countries is critically important. Overseas screening, treatment, and vaccination during planned migration to the United States represents one successful model. Thes...
Highlight:
The body of knowledge needed to effectively practice travel medicine has expanded since the 1990s, as migrants begin to comprise an increasing proportion of the world's population. We describe the unique needs of migrants and provide resources available to migration health practitioners. As the number of the world's migrants grows, coll...
Objective
To examine the potential for international travel to spread yellow fever virus to cities around the world.
Methods
We obtained data on the international flight itineraries of travellers who departed yellow fever-endemic areas of the world in 2016 for cities either where yellow fever was endemic or which were suitable for viral transmissi...
Histoplasmosis is known to be endemic to the Midwestern United States, but cases have been reported throughout much of the world. Somali, Hmong, and Burmese (ethnically Karen) persons make up some of the largest refugee populations coming the United States in recent years. Yet, information about risk of Histoplasma capsulatum infection amongst thes...
Setting:
In 2007, the US Centers for Disease Control and Prevention (CDC) revised its tuberculosis (TB) technical instructions for panel physicians who administer mandatory medical examinations among US-bound immigrants. Many US-bound immigrants come from the Philippines, a high TB prevalence country.
Objective:
To quantify economic and health i...
Yellow fever virus is a mosquito-borne flavivirus that causes yellow fever, an acute infectious disease that occurs in South America and sub-Saharan Africa. Most patients with yellow fever are asymptomatic, but among the 15% who develop severe illness, the case fatality rate is 20%-60%. Effective live-attenuated virus vaccines are available that pr...
Yellow Fever cases reported to GeoSentinel
Objective:
Despite increasing diversity in the US population, substantial gaps in collecting data on race, ethnicity, primary language, and nativity indicators persist in public health surveillance and monitoring systems. In addition, few systems provide questionnaires in foreign languages for inclusion of non-English speakers. We assessed (1) the...
65th Annual Meeting of the American-Society-of-Tropical-Medicine-and-Hygiene (ASTMH), Atlanta, GA, NOV 13-16, 2016
Introduction
When Zika virus (ZIKV) first began its spread from Brazil to other parts of the Americas, national-level travel notices were issued, carrying with them significant economic consequences to affected countries. Although regions of some affected countries were likely unsuitable for mosquito-borne transmission of ZIKV, the absence of high...
Recent manufacturing problems resulted in a shortage of the only U.S.-licensed yellow fever vaccine. This shortage is expected to lead to a complete depletion of yellow fever vaccine available for the immunization of U.S. travelers by mid-2017. CDC, the Food and Drug Administration (FDA), and Sanofi Pasteur are collaborating to ensure a continuous...
Background:
Zika virus has spread rapidly in the Americas and has been imported into many nonendemic countries by travelers.
Objective:
To describe clinical manifestations and epidemiology of Zika virus disease in travelers exposed in the Americas.
Design:
Descriptive, using GeoSentinel records.
Setting:
63 travel and tropical medicine clini...
The current global refugee crisis involves 65.3 million persons who have been displaced from their homes or countries of origin. While escaping immediate harm may be their first priority, displaced people go on to face numerous health risks, including trauma and injuries, malnutrition, infectious diseases, exacerbation of existing chronic diseases,...
Using data from travelers to 4 countries in the Middle East, we estimated 3,250 (95% CI 1,300-6,600) severe cases of Middle East respiratory syndrome occurred in this region during September 2012-January 2016. This number is 2.3-fold higher than the number of laboratory-confirmed cases recorded in these countries.
Middle East respiratory syndrome has been reported among travelers returning from the Arabian Peninsula, where most cases have been recorded. Using data from travelers, we estimated 3,250 (1,300-6,600) severe cases occurred in the Middle East during September 2012 January 2016. This estimate is 2.3-fold higher than the total laboratory-confirmed ca...
The only available vaccine in use against TB in humans today is BCG, a live attenuated vaccine derived from the bovine pathogen Mycobacterium bovis. BCG presents variable protection against pulmonary forms of TB. Genomic comparative studies have shown loss of a number of major mycobacterial antigens and about 23% of M. tuberculosis-specific human T...
Approximately 70,000-90,000 refugees are resettled to the United States each year, and during the next 5 years, 50,000 Congolese refugees are expected to arrive in the United States. The International Organization for Migration (IOM) performs refugee medical examinations overseas for the U.S. Refugee Resettlement Program. In 2014, IOM reported that...
Background:
Many U.S.-bound refugees travel from countries where intestinal parasites (hookworm, Trichuris trichuria, Ascaris lumbricoides, and Strongyloides stercoralis) are endemic. These infections are rare in the United States and may be underdiagnosed or misdiagnosed, leading to potentially serious consequences. This evaluation examined the c...
Estimated means and standard deviations for each uncertain parameter included in the analysis.
(DOCX)
Online Treeage analysis file.
(TREX)
Epidemiological and economic input parameters.
(DOCX)
Online Appendix.
(DOCX)
Zika virus belongs to the genus Flavivirus of the family Flaviviridae; it is transmitted to humans primarily through the bite of an infected Aedes species mosquito (e.g., Ae. aegypti and Ae. albopictus) (1). Zika virus has been identified as a cause of congenital microcephaly and other serious brain defects (2). As of June 30, 2016, CDC had issued...
During the 2014-2016 Ebola virus disease (Ebola) epidemic in West Africa, CDC implemented travel and border health measures to prevent international spread of the disease, educate and protect travelers and communities, and minimize disruption of international travel and trade. CDC staff provided in-country technical assistance for exit screening in...
Introduction: Air, land, and sea transportation can facilitate rapid spread of infectious diseases. In May 2015 the Pan American Health Organization (PAHO) issued an alert regarding the first confirmed Zika virus infection in Brazil. As of March 8, 2016, the U.S. Centers for Disease Control and Prevention (CDC) had issued travel notices for 33 coun...
Since May 2015, when Zika virus, a flavivirus transmitted primarily by Aedes aegypti mosquitoes, was reported in Brazil, the virus has rapidly spread across the Region of the Americas and the Caribbean. The association between maternal Zika virus infection and adverse fetal and reproductive outcomes, including microcephaly, prompted CDC to issue a...
Applying qualitative historical methods, we examined the consideration and implementation of school closures as a nonpharmaceutical intervention (NPI) in thirty US cities during the spring 2009 wave of the pA(H1N1) influenza pandemic. We gathered and performed close textual readings of official federal, state, and municipal government documents; me...
Background:
This study explored the effect of screening and treatment of refugees for latent tuberculosis infection (LTBI) before entrance to the United States as a strategy for reducing active tuberculosis (TB). The purpose of this study was to estimate the costs and benefits of LTBI screening and treatment in United States bound refugees prior t...
The 2014–2015 Ebola virus disease (Ebola) outbreak in West Africa is the largest in history, and as of October 4, 2015, had claimed 11,297 lives in Guinea, Liberia, and Sierra Leone (1). On August 7, 2014, CDC first posted guidance on monitoring and movement of persons who might have been exposed to Ebola virus to prevent the spread of Ebola into t...
Funding to support research in wound care is scarce. The NINR has the smallest annual budget of all the National Institutes of Health at $136 million (4). Commercial industry could do more to supplement wound care research. Of the 10 leading manufacturers of products for evidence-based practices (for example, underpads, dressings, beds, and creams)...
The Centers for Disease Control and Prevention is considering implementation of overseas medical screening of student-visa applicants to reduce the numbers of active tuberculosis cases entering the United States.
To evaluate the costs, cases averted, and cost-effectiveness of screening for, and treating, tuberculosis in United States-bound students...
Before 2007, immigrants and refugees bound for the United States were screened for tuberculosis (TB) by a smear-based algorithm that could not diagnose smear-negative/culture-positive TB. In 2007, the Centers for Disease Control and Prevention implemented a culture-based algorithm.
To evaluate the effect of the culture-based algorithm on preventing...
The United Nations High Commission for Refugees (UNHCR) has estimated that over 40 million people [1] are currently displaced and have variable access to health care in the country in which they reside. Populations displaced by conflict are largely disenfranchised, and high prevalence of neglected tropical diseases (NTDs) has been documented [2]. N...
The WHO declared the 2014 west African Ebola epidemic a public health emergency of international concern in view of its potential for further international spread. Decision makers worldwide are in need of empirical data to inform and implement emergency response measures. Our aim was to assess the potential for Ebola virus to spread across internat...
In response to the largest recognized Ebola virus disease epidemic now occurring in West Africa, the governments of affected countries, CDC, the World Health Organization (WHO), and other international organizations have collaborated to implement strategies to control spread of the virus. One strategy recommended by WHO calls for countries with Ebo...
Mycobacterium tuberculosis, the causative agent of tuberculosis, induces apoptosis in infected macrophages in vitro and in vivo. However, the molecular mechanism controlling this process is not known. In order to study the involvement of the mitochondrial apoptotic pathway in M. tuberculosis-induced apoptosis, we analysed cell death in M. tuberculo...
Background: For the first time, an outbreak of chikungunya has been reported in the Americas. Locally acquired infections have been confirmed in fourteen Caribbean countries and dependent territories, Guyana and French Guiana, in which a large number of North American travelers vacation. Should some travelers become infected with chikungunya virus,...
Since mid-March 2014, the frequency with which cases of Middle East respiratory syndrome coronavirus (MERS-CoV) infection have been reported has increased, with the majority of recent cases reported from Saudi Arabia and United Arab Emirates (UAE). In addition, the frequency with which travel-associated MERS cases have been reported and the number...
Active tuberculosis (TB) is a reportable communicable disease in all 50 states, but nationwide, county-level data are not released publicly. The CDC’s Online Tuberculosis Information System (OTIS) provides public surveillance data only by state. Owing to an agreement with the states, the CDC cannot publicly release TB data at the county level, prec...
The U.S. fully implemented the International Health Regulations and submitted 59 potential Public Health Emergencies of International Concern (PHEIC) to WHO since 2007. The 2009 H1N1influenza pandemic, first notified as required notification of a novel strain of influenza by the U.S., is the only event determined to be a PHEIC by WHO to date. The p...
School closure is a non-pharmaceutical intervention that was considered in many national pandemic plans developed prior to the start of the influenza A(H1N1)pdm09 pandemic, and received considerable attention during the event. Here, we retrospectively review and compare national and local experiences with school closures in several countries during...
For more than two decades, as the number of tuberculosis (TB) cases overall in the United States has declined, the proportion of cases among foreign-born persons has increased. In 2013, the percentage of TB cases among those born outside the country was 64.6%. To address this trend, CDC has developed strategies to identify and treat TB in U.S.-boun...
