The Implementation of CDC COVID-19 Recommendations for Testing, Isolation, Quarantine and Movement at Emergency Intake Sites of Unaccompanied Children in the United States, April 1-May 31, 2021

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 and bed capacity across EIS from April 1-May 31, 2021. Results: Of 11 EIS sites analyzed, 54% implemented the recommended ZP. The overall % positivity was 2.47% (95% CI 2.39-2.55). The % positivity at EIS with the ZP, 1.83% (95% CI 1.71-1.95), was lower than that at EIS without the ZP, 2.83%, ( 95% CI 2.72-2.93), and showed a lower 7-day moving average of % positivity. Conclusion: Results showed a possible effect of the ZP on % positivity when controlling for venue type and bed capacity in a specific EIS group comparison, indicating that all three variables could have had effect on % positivity. They also showed that smaller intake facilities may be recommendable during public health emergencies.

Using spatial and population mobility models to inform outbreak response approaches in the Ebola affected area, Democratic Republic of the Congo, 2018-2020

The Democratic Republic of the Congo's (DRC) 10th known Ebola virus disease (EVD) outbreak occurred between August 1, 2018 and June 25, 2020, and was the largest EVD outbreak in the country's history. During this outbreak, the DRC Ministry of Health initiated traveller health screening at points of control (POC, locations not on the border) and points of entry (POE) to minimize disease translocation via ground and air travel. We sought to develop a model-based approach that could be applied in future outbreaks to inform decisions for optimizing POC and POE placement, and allocation of resources more broadly, to mitigate the risk of disease translocation associated with ground-level population mobility. We applied a parameter-free mobility model, the radiation model, to estimate likelihood of ground travel between selected origin locations (including Beni, DRC) and surrounding population centres, based on population size and drive-time. We then performed a road network route analysis and included estimated population movement results to calculate the proportionate volume of travellers who would move along each road segment; this reflects the proportion of travellers that could be screened at a POC or POE. For Beni, the road segments estimated to have the highest proportion of travellers that could be screened were part of routes into Uganda and Rwanda. Conversely, road segments that were part of routes to other population centres within the DRC were estimated to have relatively lower proportions. We observed a posteriori that, in many instances, our results aligned with locations that were selected for actual POC or POE placement through more time-consuming methods. This study has demonstrated that mobility models and simple spatial techniques can help identify potential locations for health screening at newly placed POC or existing POE during public health emergencies based on expected movement patterns. Importantly, we have provided methods to estimate the proportionate volume of travellers that POC or POE screening measures would assess based on their location. This is critical information in outbreak situations when timely decisions must be made to implement public health interventions that reach the most individuals across a network.

Modelling airport catchment areas to anticipate the spread of infectious diseases across land and air travel

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 geographic extent from which the airport derives most of its patronage. While airport catchment areas can provide a simple decision-support tool to help delineate the spatial extent of infectious disease spread at a local scale, observed data for airport catchment areas are rarely made publicly available. Therefore, we evaluated a probabilistic choice behavior model, the Huff model, as a potential methodology to estimate airport catchment areas in the United States in data-limited scenarios. We explored the impact of varying input parameters to the Huff model on estimated airport catchment areas: distance decay exponent, distance cut-off, and measures of airport attractiveness. We compared Huff model catchment area patterns for Miami International Airport (MIA) and Harrisburg International Airport (MDT). We specifically compared our model output to observed data sampled for MDT to align model parameters with an established, observed catchment area. Airport catchment areas derived using the Huff model were highly sensitive to changes in model parameters. We observed that a distance decay exponent of 2 and a distance cut-off of 500 km represented the most realistic spatial extent and heterogeneity of the MIA catchment area. When these parameters were applied to MDT, the Huff model produced similar spatial patterns to the observed MDT catchment area. Finally, our evaluation of airport attractiveness showed that travel volume to the specific international destinations of interest for infectious disease importation risks (i.e., Brazil) had little impact on the predicted choice of airport when compared to all international travel. Our work is a proof of concept for use of the Huff model to estimate airport catchment areas as a generalizable decision-support tool in data-limited scenarios. While our work represents an initial examination of the Huff model as a method to approximate airport catchment areas, an essential next step is to conduct a quantitative calibration and validation of the model based on multiple airports, possibly leveraging local human mobility data such as call detail records or online social network data collected from mobile devices. Ultimately, we demonstrate how the Huff model could be potentially helpful to improve the precision of early warning systems that anticipate infectious disease spread, or to incorporate when local public health decision makers need to identify where to mobilize screening infrastructure or containment strategies at a local level.

An immunization program for US-bound refugees: Development, challenges, and opportunities 2012-present

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 and the US Department of State developed and co-funded a global immunization program for US-bound refugees, implemented in 2012 in collaboration with the International Organization for Migration.

METHODS

We describe the Vaccination Program for US-bound Refugees, including vaccination schedule development, program implementation and procedures, and responses to challenges. We estimate 2019 immunization coverage rates using the number of age-eligible refugees who received ≥1 dose of measles-containing vaccine during overseas health assessment, and calculated hepatitis B infection prevalence using hepatitis B surface antigen testing results. We report descriptive data on adverse events following immunization.

RESULTS

By September 2019, the program was active in >80 countries on five continents. Nearly 320,000 examined refugees had ≥1 documented vaccine doses since program inception. During federal fiscal year 2019, 95% of arriving refugees had ≥1 documented measles-containing vaccine. The program's immunization schedule included eleven vaccines preventing fourteen diseases. In 2015-2019, only two vaccine preventable disease-associated refugee group travel cancellations occurred, compared to 2-8 cancellations annually prior to program initiation. To maintain uniform standards, dedicated staff and program-specific protocols for vaccination and monitoring were introduced.

CONCLUSIONS

An overseas immunization program was successfully implemented for US-bound refugees. Due to reductions in refugee movement cancellation, lower cost of immunization overseas, and likely reductions in vaccine preventable disease-associated morbidity, we anticipate significant cost savings. Although maintaining uniform standards across diverse settings is challenging, solutions such as introduction of dedicated staff, protocol development, and ongoing technical support have ensured program cohesion, continuity, and advancement. Lessons learned can benefit similar programs implemented in the migration setting.

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 Check and Report Ebola (CARE+) Program to Monitor Travelers for Ebola After Arrival to the United States, 2014-2016

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 Ebola while continuing to allow travel from West Africa. This case study describes a new initiative, the Check and Report Ebola (CARE+) program that engaged travelers arriving to the United States from countries with Ebola outbreaks. The Centers for Disease Control and Prevention employed CARE ambassadors, who quickly communicated with incoming travelers and gave them practical resources to boost their participation in monitoring for Ebola. The program aimed to increase travelers' knowledge of Ebola symptoms and how to seek medical care safely, increase travelers' awareness of monitoring requirements, reduce barriers to monitoring, and increase trust in the US public health system. This program could be adapted for use in future outbreaks that involve the potential importation of disease and require the education and active engagement of travelers to participate in post-arrival monitoring.

International travel between global urban centres vulnerable to yellow fever transmission

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 transmission. Using a global ecological model of dengue virus transmission, we predicted the suitability of cities in non-endemic areas for yellow fever transmission. We obtained information on national entry requirements for yellow fever vaccination at travellers' destination cities.

FINDINGS

In 2016, 45.2 million international air travellers departed from yellow fever-endemic areas of the world. Of 11.7 million travellers with destinations in 472 cities where yellow fever was not endemic but which were suitable for virus transmission, 7.7 million (65.7%) were not required to provide proof of vaccination upon arrival. Brazil, China, India, Mexico, Peru and the United States of America had the highest volumes of travellers arriving from yellow fever-endemic areas and the largest populations living in cities suitable for yellow fever transmission.

CONCLUSION

Each year millions of travellers depart from yellow fever-endemic areas of the world for cities in non-endemic areas that appear suitable for viral transmission without having to provide proof of vaccination. Rapid global changes in human mobility and urbanization make it vital for countries to re-examine their vaccination policies and practices to prevent urban yellow fever epidemics.

Travel Volume to the United States from Countries and U.S. Territories with Local Zika Virus Transmission

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 countries and 3 U.S. territories with local Zika virus transmission.

Methods: Using data from five separate datasets from 2014 and 2015, we estimated the annual number of passenger journeys by air and land border crossings to the United States from the 33 countries and 3 U.S. territories listed in the CDC’s Zika travel notices as of March 8, 2016. We also estimated the annual number of passenger journeys originating in and returning to the United States (primarily on cruises) with visits to seaports in areas with local Zika virus transmission. Because of the adverse pregnancy and birth outcomes that have been associated with Zika virus disease, the number of passenger journeys completed by women of childbearing age and pregnant women was also estimated.

Results: An estimated 216.3 million passenger journeys by air, land, and sea are made annually to the United States from areas with local Zika virus transmission (as of March 8). The destination states with the largest numbers of arrivals were Texas (by land) and Florida (by air and sea). An estimated 51.7 million passenger journeys were made by women of childbearing age and an estimated 2.3 million were made by pregnant women.

Conclusion: Travel volume analyses provide important information that can be used to effectively target public health interventions as well as direct public health resources and efforts at local, regional, and country-specific levels.

Revision to CDC's Zika Travel Notices: Minimal Likelihood for Mosquito-Borne Zika Virus Transmission at Elevations Above 2,000 Meters

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 Level 2 alert travel notice* for the 37 countries and U.S. territories (at the national and territorial level) that have reported recent Zika virus transmission as of March 11, 2016. In addition to mosquito bite precautions for all travelers, CDC advises that pregnant women postpone travel to affected countries and U.S. territories. Within a nation's borders, ecologic characteristics, which determine the distribution of mosquito vectors, can vary considerably. CDC conducted a spatial analysis, focusing on the probability of occurrence of Ae. aegypti, to support the demarcation for subnational travel alerts. Based on results of this analysis, travel that is limited to elevations higher than 2,000 m (6,562 ft) above sea level is considered to have minimal (approximately 1%) likelihood for mosquito-borne Zika virus transmission, even within countries reporting active transmission. Women who are pregnant should avoid travel to elevations <2,000 m in countries with active Zika virus transmission.

Assessing the origin of and potential for international spread of chikungunya virus from the Caribbean

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, they could potentially introduce it into the United States, where there are competent Aedes mosquito vectors, with the possibility of local transmission.

METHODS

We analyzed historical data on airline travelers departing areas of the Caribbean and South America, where locally acquired cases of chikungunya have been confirmed as of May 12th, 2014. The final destinations of travelers departing these areas between May and July 2012 were determined and overlaid on maps of the reported distribution of Aedes aeygpti and albopictus mosquitoes in the United States, to identify potential areas at risk of autochthonous transmission.

RESULTS

The United States alone accounted for 52.1% of the final destinations of all international travelers departing chikungunya indigenous areas of the Caribbean between May and July 2012. Cities in the United States with the highest volume of air travelers were New York City, Miami and San Juan (Puerto Rico). Miami and San Juan were high travel-volume cities where Aedes aeygpti or albopictus are reported and where climatic conditions could be suitable for autochthonous transmission.

CONCLUSION

The rapidly evolving outbreak of chikungunya in the Caribbean poses a growing risk to countries and areas linked by air travel, including the United States where competent Aedes mosquitoes exist. The risk of chikungunya importation into the United States may be elevated following key travel periods in the spring, when large numbers of North American travelers typically vacation in the Caribbean.

First confirmed cases of Middle East respiratory syndrome coronavirus (MERS-CoV) infection in the United States, updated information on the epidemiology of MERS-CoV infection, and guidance for the public, clinicians, and public health authorities - May 2014

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 of countries that have reported them to the World Health Organization (WHO) have also increased. The first case of MERS in the United States, identified in a traveler recently returned from Saudi Arabia, was reported to CDC by the Indiana State Department of Health on May 1, 2014, and confirmed by CDC on May 2. A second imported case of MERS in the United States, identified in a traveler from Saudi Arabia having no connection with the first case, was reported to CDC by the Florida Department of Health on May 11, 2014. The purpose of this report is to alert clinicians, health officials, and others to increase awareness of the need to consider MERS-CoV infection in persons who have recently traveled from countries in or near the Arabian Peninsula. This report summarizes recent epidemiologic information, provides preliminary descriptions of the cases reported from Indiana and Florida, and updates CDC guidance about patient evaluation, home care and isolation, specimen collection, and travel as of May 13, 2014.

School closures during the 2009 influenza pandemic: national and local experiences

BACKGROUND

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 the A(H1N1)pdm09 pandemic. Our intention is not to make a systematic review of country experiences; rather, it is to present the diversity of school closure experiences and provide examples from national and local perspectives.

METHODS

Data were gathered during and following a meeting, organized by the European Centres for Disease Control, on school closures held in October 2010 in Stockholm, Sweden. A standard data collection form was developed and sent to all participants. The twelve participating countries and administrative regions (Bulgaria, China, France, Hong Kong Special Administrative Region (SAR), Italy, Japan, New Zealand, Serbia, South Africa, Thailand, United Kingdom, and United States) provided data.

RESULTS

Our review highlights the very diverse national and local experiences on school closures during the A(H1N1)pdm09 pandemic. The processes including who was in charge of making recommendations and who was in charge of making the decision to close, the school-based control strategies, the extent of school closures, the public health tradition of responses and expectations on school closure varied greatly between countries. Our review also discusses the many challenges associated with the implementation of this intervention and makes recommendations for further practical work in this area.

CONCLUSIONS

The single most important factor to explain differences observed between countries may have been the different public health practises and public expectations concerning school closures and influenza in the selected countries.

Potential for the international spread of middle East respiratory syndrome in association with mass gatherings in saudi arabia

Background: A novel coronavirus (MERS-CoV) causing severe, life-threatening respiratory disease has emerged in the Middle East at a time when two international mass gatherings in Saudi Arabia are imminent. While MERS-CoV has already spread to and within other countries, these mass gatherings could further amplify and/or accelerate its international dissemination, especially since the origins and geographic source of the virus remain poorly understood. Methods: We analyzed 2012 worldwide flight itinerary data and historic Hajj pilgrim data to predict population movements out of Saudi Arabia and the broader Middle East to help cities and countries assess their potential for MERS-CoV importation. We compared the magnitude of travel to countries with their World Bank economic status and per capita healthcare expenditures as surrogate markers of their capacity for timely detection of imported MERS-CoV and their ability to mount an effective public health response. Results: 16.8 million travelers flew on commercial flights out of Saudi Arabia, Jordan, Qatar, and the United Arab Emirates between June and November 2012, of which 51.6% were destined for India (16.3%), Egypt (10.4%), Pakistan (7.8%), the United Kingdom (4.3%), Kuwait (3.6%), Bangladesh (3.1%), Iran (3.1%) and Bahrain (2.9%). Among the 1.74 million foreign pilgrims who performed the Hajj last year, an estimated 65.1% originated from low and lower-middle income countries. Conclusion: MERS-CoV is an emerging pathogen with pandemic potential with its apparent epicenter in Saudi Arabia, where millions of pilgrims will imminently congregate for two international mass gatherings. Understanding global population movements out of the Middle East through the end of this year's Hajj could help direct anticipatory MERS-CoV surveillance and public health preparedness to mitigate its potential global health and economic impacts.

Selecting nonpharmaceutical strategies to minimize influenza spread: the 2009 influenza A (H1N1) pandemic and beyond

Shortly after the influenza A (H1N1) 2009 pandemic began, the U.S. government provided guidance to state and local authorities to assist decision-making for the use of nonpharmaceutical strategies to minimize influenza spread. This guidance included recommendations for flexible decision-making based on outbreak severity, and it allowed for uncertainty and course correction as the pandemic progressed. These recommendations build on a foundation of local, collaborative planning and posit a series of questions regarding epidemiology, the impact on the health-care system, and locally determined feasibility and acceptability of nonpharmaceutical strategies. This article describes -recommendations and key questions for decision makers.

Spectrum of illness in international migrants seen at GeoSentinel clinics in 1997-2009, part 1: US-bound migrants evaluated by comprehensive protocol-based health assessment

BACKGROUND

Many nations are struggling to develop structured systems and guidelines to optimize the health of new arrivals, but there is currently no international consensus about the best approach.

METHODS

Data on 7792 migrants who crossed international borders for the purpose of resettlement and underwent a protocol-based health assessment were collected from the GeoSentinel Surveillance network. Demographic and health characteristics of a subgroup of these migrants seen at 2 US-based GeoSentinel clinics for protocol-based health assessments are described.

RESULTS

There was significant variation over time in screened migrant populations and in their demographic characteristics. Significant diagnoses identified in all migrant groups included latent tuberculosis, found in 43% of migrants, eosinophilia in 15%, and hepatitis B infection in 6%. Variation by region occurred for select diagnoses such as parasitic infections. Notably absent were infectious tuberculosis, soil-transmitted helminths, and malaria. Although some conditions would be unfamiliar to clinicians in receiving countries, universal health problems such as dental caries, anemia, ophthalmologic conditions, and hypertension were found in 32%, 11%, 10%, and 5%, respectively, of screened migrants.

CONCLUSIONS

Data from postarrival health assessments can inform clinicians about screening tests to perform in new immigrants and help communities prepare for health problems expected in specific migrant populations. These data support recommendations developed in some countries to screen all newly arriving migrants for some specific diseases (such as tuberculosis) and can be used to help in the process of developing additional screening recommendations that might be applied broadly or focused on specific at-risk populations.

Spectrum of illness in international migrants seen at GeoSentinel clinics in 1997-2009, part 2: migrants resettled internationally and evaluated for specific health concerns

BACKGROUND

Increasing international migration may challenge healthcare providers unfamiliar with acute and long latency infections and diseases common in this population. This study defines health conditions encountered in a large heterogenous group of migrants.

METHODS

Migrants seen at GeoSentinel clinics for any reason, other than those seen at clinics only providing comprehensive protocol-based health screening soon after arrival, were included. Proportionate morbidity for syndromes and diagnoses by country or region of origin were determined and compared.

RESULTS

A total of 7629 migrants from 153 countries were seen at 41 GeoSentinel clinics in 19 countries. Most (59%) were adults aged 19-39 years; 11% were children. Most (58%) were seen >1 year after arrival; 27% were seen after >5 years. The most common diagnoses were latent tuberculosis (22%), viral hepatitis (17%), active tuberculosis (10%), human immunodeficiency virus (HIV)/AIDS (7%), malaria (7%), schistosomiasis (6%), and strongyloidiasis (5%); 5% were reported healthy. Twenty percent were hospitalized (24% for active tuberculosis and 21% for febrile illness [83% due to malaria]), and 13 died. Tuberculosis diagnoses and HIV/AIDS were reported from all regions, strongyloidiasis from most regions, and chronic hepatitis B virus (HBV) particularly in Asian immigrants. Regional diagnoses included schistosomiasis (Africa) and Chagas disease (Americas).

CONCLUSIONS

Eliciting a migration history is important at every encounter; migrant patients may have acute illness or chronic conditions related to exposure in their country of origin. Early detection and treatment, particularly for diagnoses related to tuberculosis, HBV, Strongyloides, and schistosomiasis, may improve outcomes. Policy makers should consider expansion of refugee screening programs to include all migrants.

A randomized, double-blind, controlled trial of the 17D yellow fever virus vaccine given in combination with immune globulin or placebo: comparative viremia and immunogenicity

We evaluated whether coadministration of the yellow fever (YF) virus vaccine with human immunoglobulin (Ig) that contained YF virus-neutralizing antibodies would reduce post-vaccination viremia without compromising immunogenicity and thus, potentially mitigate YF vaccine-associated adverse events. We randomized 80 participants to receive either YF vaccine and Ig or YF vaccine and saline placebo. Participants were followed for 91 days for safety and assessments of viremia and immunogenicity. There were no differences found between the two groups in the proportion of vaccinated participants who developed viremia, seroconversion, cluster of differentiation (CD)-8(+) and CD4(+) T-cell responses, and cytokine responses. These results argue against one putative explanation for the increased reporting of YF vaccine side effects in recent years (i.e., a change in travel clinic practice after 1996 when hepatitis A prophylaxis with vaccine replaced routine use of pre-travel Ig, thus potentially removing an incidental YF vaccine-attenuating effect of anti-YF virus antibodies present in Ig).

Neurologic disease associated with 17D-204 yellow fever vaccination: a report of 15 cases

Yellow fever (YF), can be prevented by an attenuated vaccine (YEL). We reviewed neurologic adverse events (AE) following YEL that were reported to the national Vaccine Adverse Events Reporting System (VAERS). VAERS is a passive reporting system with inherent limitations for causality assessment. Based on defined criteria, five cases of encephalitis were classified as 'definitely' and one of acute disseminated encephalomyelitis (ADEM) as 'probably' caused by YEL. Six cases of Guillain-Barre Syndrome (GBS), one of encephalitis, and two of ADEM, were classified as 'suspect' vaccine-associated disease. Laboratory and epidemiological evidence suggests that YEL caused encephalitis. Additional studies will be required to confirm whether YEL can rarely result in GBS and/or ADEM.

Improved sensitivity of sputum smear microscopy after processing specimens with C18-carboxypropylbetaine to detect acid-fast bacilli: a study of United States-bound immigrants from Vietnam

The goal of this study was to evaluate the effect of the specimen-processing method that uses the detergent C18-carboxypropylbetaine (CB-18) on the sensitivity of acid-fast bacillus (AFB) staining. Vietnamese immigrants with abnormal chest radiographs provided up to three sputum specimens, which were examined for acid-fast bacilli by use of direct auramine and Ziehl-Neelsen staining. The remaining sputum was split; half was cultured, and the other half was incubated with CB-18 for 24 h, centrifuged, and examined for AFB by both staining methods. CB-18 processing improved the sensitivity of AFB staining by 20 to 30% (only differences in auramine sensitivity were statistically significant) but reduced specificity by approximately 20% (P < 0.05). These findings have direct utility for overseas migrant tuberculosis screening programs, for which maximizing test sensitivity is a major objective.

Schistosome infection among river rafters on Omo River, Ethiopia

BACKGROUND

Adventure trips to Africa have become more frequent, and rafting on some of the great rivers has become almost commonplace. We describe three rafting trips on the Omo River in Ethiopia, after which most of the participants were diagnosed with schistosomiasis.

METHODS

After index cases from the three groups came to medical attention, active surveillance detected outbreaks of illness in a group of American travelers (n = 18 ) in 1993 and in two groups of Israeli travelers in 1997 (n = 26).

RESULTS

Of 44 travelers, 37 were screened and 28 (76%) were infected, all with Schistosoma mansoni. Among the infected patients, 16 of 28 (57%) were symptomatic, the most frequent manifestation being fever, which occurred in 14 of 25 (56%); cough occurred in 6 of 18 (33%). Diagnosis was based on FAST-enzyme-linked immunosorbent assay, with confirmation by immunoblot. Other rafting trips on the Omo River sponsored by the same tour companies did not result in symptomatic infection. Investigation of the rafting itineraries suggested the route may have been altered from the usual for these three groups, exposing them to a part of the river that is wider, slower moving, and more densely populated.

CONCLUSIONS

Schistosomiasis should be considered in febrile patients following rafting trips in schistosome-endemic areas. As asymptomatic schistosomiasis in travelers is also common (43% in this series), all travelers exposed to freshwater in endemic areas should be encouraged to undergo serologic screening.

Severe histoplasmosis in travelers to Nicaragua

We investigated an outbreak of unexpectedly severe histoplasmosis among 14 healthy adventure travelers from the United States who visited a bat-infested cave in Nicaragua. Although histoplasmosis has rarely been reported to cause serious illness among travelers, this outbreak demonstrates that cases may be severe among travelers, even young, healthy persons.

Delayed onset of malaria--implications for chemoprophylaxis in travelers

BACKGROUND

Most antimalarial agents used by travelers act on the parasite's blood stage and therefore do not prevent late-onset illness, particularly that due to species that cause relapsing malaria. We examined the magnitude of this problem among Israeli and American travelers.

METHODS

We examined malaria surveillance data from Israel and the United States to determine the traveler's destination, the infecting species, the type of chemoprophylaxis used, and the incubation period.

RESULTS

In Israel, from 1994 through 1999, there were 300 cases of malaria among returning travelers in which one species of plasmodium could be identified. In 134 of these cases (44.7 percent), the illness developed more than two months after the traveler's return; nearly all of these cases were due to infection with Plasmodium vivax or P. ovale. In 108 of the 134 cases (80.6 percent), the patient had used an antimalarial regimen according to national guidelines. In the United States, from 1992 through 1998, there were 2822 cases of malaria among travelers in which the cause could be evaluated. Late illness developed in 987 (35.0 percent) of these travelers. The infection was due to P. vivax in 811 travelers, P. ovale in 66, P. falciparum in 59, and P. malariae in 51; 614 (62.2 percent) of those with late-onset illness had appropriately taken an effective antimalarial agent.

CONCLUSIONS

In more than one third of malaria-infected travelers, the illness developed more than two months after their return. Most of these late-onset illnesses are not prevented by the commonly used and effective blood schizonticides. Agents that act on the liver phase of malaria parasites are needed for more effective prevention of malaria in travelers.

The U.S.-Mexico Border Infectious Disease Surveillance project: establishing bi-national border surveillance

In 1997, the Centers for Disease Control and Prevention, the Mexican Secretariat of Health, and border health officials began the development of the Border Infectious Disease Surveillance (BIDS) project, a surveillance system for infectious diseases along the U.S.-Mexico border. During a 3-year period, a binational team implemented an active, sentinel surveillance system for hepatitis and febrile exanthems at 13 clinical sites. The network developed surveillance protocols, trained nine surveillance coordinators, established serologic testing at four Mexican border laboratories, and created agreements for data sharing and notification of selected diseases and outbreaks. BIDS facilitated investigations of dengue fever in Texas-Tamaulipas and measles in California-Baja California. BIDS demonstrates that a binational effort with local, state, and federal participation can create a regional surveillance system that crosses an international border. Reducing administrative, infrastructure, and political barriers to cross-border public health collaboration will enhance the effectiveness of disease prevention projects such as BIDS.

Increasing prevalence of multidrug-resistant Streptococcus pneumoniae in the United States

BACKGROUND

The emergence of drug-resistant strains of bacteria has complicated treatment decisions and may lead to treatment failures.

METHODS

We examined data on invasive pneumococcal disease in patients identified from 1995 to 1998 in the Active Bacterial Core Surveillance program of the Centers for Disease Control and Prevention. Pneumococci that had a high level of resistance or had intermediate resistance according to the definitions of the National Committee for Clinical Laboratory Standards were defined as "resistant" for this analysis.

RESULTS

During 1998, 4013 cases of invasive Streptococcus pneumoniae disease were reported (23 cases per 100,000 population); isolates were available for 3475 (87 percent). Overall, 24 percent of isolates from 1998 were resistant to penicillin. The proportion of isolates that were resistant to penicillin was highest in Georgia (33 percent) and Tennessee (35 percent), in children under five years of age (32 percent, vs. 21 percent for persons five or more years of age), and in whites (26 percent, vs. 22 percent for blacks). Penicillin-resistant isolates were more likely than susceptible isolates to have a high level of resistance to other antimicrobial agents. Serotypes included in the 7-valent conjugate and 23-valent pneumococcal polysaccharide vaccines accounted for 78 percent and 88 percent of penicillin-resistant strains, respectively. Between 1995 and 1998 (during which period 12,045 isolates were collected), the proportion of isolates that were resistant to three or more classes of drugs increased from 9 percent to 14 percent; there also were increases in the proportions of isolates that were resistant to penicillin (from 21 percent to 25 percent), cefotaxime (from 10 percent to 15 percent), meropenem (from 10 percent to 16 percent), erythromycin (from 11 percent to 16 percent), and trimethoprim-sulfamethoxazole (from 25 percent to 29 percent). The increases in the frequency of resistance to other antimicrobial agents occurred exclusively among penicillin-resistant isolates.

CONCLUSIONS

Multidrug-resistant pneumococci are common and are increasing. Because a limited number of serotypes account for most infections with drug-resistant strains, the new conjugate vaccines offer protection against most drug-resistant strains of S. pneumoniae.

Cruise ships: high-risk passengers and the global spread of new influenza viruses

In 1997, passengers on North American cruises developed acute respiratory illnesses (ARIs); influenza was suspected. We reviewed 1 ship's medical records for 3 cruises: cruise 1 (31 August to 10 September 1997), cruise 2 (11-20 September 1997), and cruise 3 (20-30 September 1997). Medically attended ARI was defined as any 2 of the following symptoms: fever (temperature, > or =37.8 degrees C) or feverishness, sore throat, cough, nasal congestion, chills, myalgia, and arthralgia. During cruise 2, we collected nasopharyngeal swabs for viral culture from people with ARI and surveyed passengers for self-reported ARI (defined as above except feverishness was substituted for fever). The outbreak probably began among Australian passengers on cruise 1 (relative risk, 3.3; 95% confidence interval, 1.89-5.77). Of 1284 passengers on cruise 2, 215 (17%) reported ARI, 994 (77%) were aged > or =65 years, and 336 (26%) had other risk factors for respiratory complications. An influenza strain not previously identified in North America was isolated. We concluded that an "off-season" influenza outbreak occurred among international travelers and crew on board this cruise ship.

Clinical outcomes of meningitis caused by Streptococcus pneumoniae in the era of antibiotic resistance

Limited data are available on clinical outcomes of meningitis due to cefotaxime-nonsusceptible Streptococcus pneumoniae. We analyzed data from 109 cases of pneumococcal meningitis in Atlanta, Baltimore, and San Antonio, which were identified through population-based active surveillance from November 1994 to April 1996. Pneumococcal isolates from 9% of the cases were resistant to cefotaxime, and isolates from 11% had intermediate susceptibility. Children were more likely to have cephalosporin-nonsusceptible pneumococcal meningitis, but mortality was significantly higher among adults aged 18-64 years. Vancomycin was given upon admission to 29% of patients, and within 48 h of admission to 52%. Nonsusceptibility to cefotaxime was not associated with the following outcomes: increased mortality, prolonged length of hospital or intensive care unit (ICU) stay, requirement of intubation or oxygen, ICU care, discharge to another medical or long-term-care facility, or neurological deficit. Empirical use of vancomycin, current prevalence of drug-resistant S. pneumoniae, and degree of nonsusceptibility to cefotaxime may have influenced these findings.

Risk factors for community-acquired pneumonia among persons infected with human immunodeficiency virus

Two hundred eleven adults with human immunodeficiency virus (HIV) infection hospitalized for community-acquired pneumonia, including Pneumocystis carinii pneumonia (PCP; patients), and 192 matched HIV-infected hospitalized patients without pneumonia (controls) were interviewed to determine risk factors for pneumonia. Multivariate logistic regression showed that patients were less likely than controls to have used trimethoprim-sulfamethoxazole (TMP-SMZ) prophylaxis (odds ratio [OR], 0.22; 95% confidence interval [CI], 0.12-0.41) and more likely to have been hospitalized previously with pneumonia (OR, 6.25; CI, 3.40-11.5). Patients were also more likely than controls to have gardened (OR, 2.24; CI, 1.00-5.02) and to have camped or hiked (OR, 4.95; CI, 1.31-18.7), but stratified analysis by etiologic agent showed this association only for PCP. These findings reconfirm the efficacy of TMP-SMZ in preventing community-acquired pneumonia. In addition, hospitalization for pneumonia might represent a missed opportunity to encourage HIV-infected patients to enter into regular medical care and to adhere to prescribed antiretroviral and prophylaxis medications.

A community outbreak of Legionnaires' disease linked to hospital cooling towers: an epidemiological method to calculate dose of exposure

BACKGROUND

From July to September 1994, 29 cases of community-acquired Legionnaires' disease (LD) were reported in Delaware. The authors conducted an investigation to a) identify the source of the outbreak and risk factors for developing Legionella pneumophila serogroup 1 (Lp-1) pneumonia and b) evaluate the risk associated with the components of cumulative exposure to the source (i.e. distance from the source, frequency of exposure, and duration of exposure).

METHODS

A case-control study matched 21 patients to three controls per case by known risk factors for acquiring LD. Controls were selected from patients who attended the same clinic as the respective case-patients. Water samples taken at the hospital, from eight nearby cooling towers, and from four of the patient's homes were cultured for Legionella. Isolates were subtyped using monoclonal antibody (Mab) analysis and arbitrarily primed polymerase chain reaction (AP-PCR).

RESULTS

Eleven (52%) of 21 case-patients worked at or visited the hospital compared with 17 (27%) of 63 controls (OR 5.0, 95% CI : 1.1-29). For those who lived, worked, or visited within 4 square miles of the hospital, the risk of illness decreased by 20% for each 0.10 mile from the hospital; it increased by 80% for each visit to the hospital; and it increased by 8% for each hour spent within 0.125 miles of the hospital. Lp-1 was isolated from three patients and both hospital cooling towers. Based on laboratory results no other samples contained Lp-1. The clinical and main-tower isolates all demonstrated Mab pattern 1,2,5,6. AP-PCR matched the main-tower samples with those from two case-patients.

CONCLUSION

The results of our investigation suggested that the hospital cooling towers were the source of a community outbreak of LD. Increasing proximity to and frequency of exposure to the towers increased the risk of LD. New guidelines for cooling tower maintenance are needed. Knowing the location of cooling towers could facilitate maintenance inspections and outbreak investigations.

Health problems of corporate travelers: risk factors and management

BACKGROUND

Numerous studies have been done regarding health problems experienced by tourists in developing countries; however, little data exist about these health risks and illnesses experienced by corporate travelers.

METHODS

The authors examined by electronic survey the health risks encountered, compliance with pretravel health recommendations, and illnesses and injuries experienced by employees of the Coca-Cola Company who travel internationally.

RESULTS

Two hundred twenty-six travelers responded. Although most travelers ate meals at their hotels and chose foods that were cooked and still hot, over half also ate foods that remained at room temperature for prolonged periods and/or ate from cold salad bars. Almost half drank untreated tap water. Thirty-five percent of travelers developed diarrhea and 29% reported respiratory illnesses, with 12% seeking medical attention for their problems. Forty-three percent of those traveling to malarious regions admitted to noncompliance with antimalarial recommendations. Health kits provided were used by only 51% of travelers.

CONCLUSIONS

Although many corporate travelers followed pretravel health recommendations, some did not. Injuries, fever, and illnesses such as diarrhea and respiratory infections occurred. Strategies to improve access to the travel clinic and the acquisition of health information and travel health kits are being implemented. The health risks and behaviors of corporate travelers, including the potential impact of psychosocial stressors, need greater attention.

Knowledge and attitudes of hospital-based physicians and trainees about HIV infection in the United States, Canada, India, and Thailand

OBJECTIVE

To examine the attitudes and knowledge of health care professionals regarding human immunodeficiency virus (HIV) infection in countries with a varying prevalence of HIV infection to assist in the development of acquired immunodeficiency syndrome (AIDS) educational programs.

DESIGN

Anonymous questionnaire with four sections: demographics, attitudes, knowledge, and an open-ended question investigating feelings about the potential impact that HIV infection may have on respondents' practices.

PARTICIPANTS

Final-year medical students, house staff, and attending physicians at teaching hospitals in India, Thailand, Canada, and the United States.

RESULTS

From January to October 1992, 819 health care professionals completed the questionnaire: 340 from India, 196 from Canada, 155 from the United States, and 128 from Thailand. The percentage of respondents who had previous contact with patients with HIV/AIDS varied from 30% to 98%; it was lowest in India, followed by Thailand and then Canada, and highest in the United States. Percentages of respondents uncomfortable performing a physical examination on a patient with HIV/AIDS were 24%, 25%, 9%, and 4%, respectively. Mean HIV/AIDS knowledge scores were 83%, 84%, 92%, and 93%, respectively. Most respondents correctly identified modes of transmission of HIV infection. Only 67% of Indian health care professionals understood the concept of a false-negative screening serologic test, compared with 98% of Canadian health care professionals. In Canada and the United States, only 78% and 76%, respectively, understood the concept of a false-positive screening serologic test. Awareness of an asymptomatic stage of HIV infection ranged from 32% in India to 74% in Canada. Despite their concerns of becoming infected, health care professionals in countries with a lower prevalence of HIV infection reported a strong ethical duty to care for these patients.

CONCLUSIONS

Level of comfort in caring for HIV-infected patients and HIV/AIDS knowledge scores varied directly with the amount of previous contact with these patients. Disturbing numbers of health care professionals from all four countries did not understand the potential problems of the enzyme-linked immunosorbent assay serologic test and a significant percentage were unaware of the asymptomatic stage of HIV infection. There is a universal need for increased education of health care professionals about HIV infection and AIDS.