Characteristics and preparation of the last-minute traveler: analysis of vaccine usage in the Global TravEpiNet Consortium

BACKGROUND

Last-minute travellers (LMTs) present challenges for health care providers because they may have insufficient time for recommended vaccinations or pre-travel preparation. Our objective was to obtain a better understanding of LMTs in order to help travel medicine providers develop improved strategies to decrease the number of LMTs and potentially reduce travel-related morbidity.

METHODS

We defined LMTs as travellers with a departure date of 7 days or fewer from the medical encounter. We analysed the characteristics and health preparation of 12 494 LMTs who presented to a network of US clinical practices for pre-travel health advice between January 2009 and December 2015.

RESULTS

LMTs comprised 16% of all travellers. More LMTs than non-LMTs travelled for business or to visit friends and relatives (VFR) (26% vs 16% and 15% vs 8%, respectively; P < 0.0001). More LMTs also travelled for longer than 1 month (27% vs 21%; P < 0.0001) and visited only urban areas (40% vs 29%; P < 0.0001). At least one travel vaccine was deferred by 18% of LMTs because of insufficient time before departure. Vaccines that required multiple vaccinations, such as Japanese encephalitis and rabies, were the most likely to be deferred because of time constraints.

CONCLUSION

Interventions to improve the timing of pre-travel health consultations should be developed, particularly for business and VFR travellers. Recently endorsed accelerated vaccine schedules for Japanese encephalitis and rabies may help some LMTs receive protection against these infections despite late presentation for pre-travel health care.

Water quality, availability, and acute gastroenteritis on the Navajo Nation - a pilot case-control study

The Navajo Nation includes approximately 250,000 American Indians living in a remote high desert environment with limited access to public water systems. We conducted a pilot case-control study to assess associations between acute gastroenteritis (AGE) and water availability, use patterns, and quality. Case patients with AGE and non-AGE controls who presented for care to two Indian Health Service hospitals were recruited. Data on demographics and water use practices were collected using a standard questionnaire. Household drinking water was tested for presence of pathogens, coliforms, and residual chlorine. Sixty-one subjects (32 cases and 29 controls) participated in the study. Cases and controls were not significantly different with respect to water sources, quality, or patterns of use. Twenty-one percent (n = 12) of study participants resided in dwellings not connected to a community water system. Eleven percent (n = 7) of subjects reported drinking hauled water from unregulated sources. Coliform bacteria were present in 44% (n = 27) of household water samples, and 68% (n = 40) of samples contained residual chlorine concentrations of <0.2 mg/L. This study highlights issues with water availability, quality, and use patterns within the Navajo Nation, including sub-optimal access to community water systems, and use of water hauled from unregulated sources.

Potentially Serious Drug Interactions Resulting From the Pretravel Health Encounter

Travelers seen for pretravel health encounters are frequently prescribed new travel-related medications, which may interact with their previously prescribed medications. In a cohort of 76 324 travelers seen at 23 US clinics, we found that 2650 (3.5%) travelers were prescribed travel-related medications with potential for serious drug interactions.

Infectious diseases acquired by international travellers visiting the USA

BACKGROUND

Estimates of travel-related illness have focused predominantly on populations from highly developed countries visiting low- or middle-income countries, yet travel to and within high-income countries is very frequent. Despite being a top international tourist destination, few sources describe the spectrum of infectious diseases acquired among travellers to the USA.

METHODS

We performed a descriptive analysis summarizing demographic and travel characteristics, and clinical diagnoses among non-US-resident international travellers seen during or after travel to the USA at a GeoSentinel clinic from 1 January 1997 through 31 December 2016.

RESULTS

There were 1222 ill non-US-resident travellers with 1393 diagnoses recorded during the 20-year analysis period. Median age was 40 (range 0-86 years); 52% were female. Patients visited from 63 countries and territories, most commonly Canada (31%), Germany (14%), France (9%) and Japan (7%). Travellers presented with a range of illnesses; skin and soft tissue infections of unspecified aetiology were the most frequently reported during travel (29 diagnoses, 14% of during-travel diagnoses); arthropod bite/sting was the most frequently reported after travel (173 diagnoses, 15% after-travel diagnoses). Lyme disease was the most frequently reported arthropod-borne disease after travel (42, 4%). Nonspecific respiratory, gastrointestinal and systemic infections were also among the most frequently reported diagnoses overall. Low-frequency illnesses (<2% of cases) made up over half of diagnoses during travel and 41% of diagnoses after travel, including 13 cases of coccidioidomycosis and mosquito-borne infections like West Nile, dengue and Zika virus diseases.

CONCLUSIONS

International travellers to the USA acquired a diverse array of mostly cosmopolitan infectious diseases, including nonspecific respiratory, gastrointestinal, dermatologic and systemic infections comparable to what has been reported among travellers to low- and middle-income countries. Clinicians should consider the specific health risks when preparing visitors to the USA and when evaluating and treating those who become ill.

Leptospirosis among Returned Travelers: A GeoSentinel Site Survey and Multicenter Analysis-1997-2016

Leptospirosis is a potentially fatal emerging zoonosis with worldwide distribution and a broad range of clinical presentations and exposure risks. It typically affects vulnerable populations in (sub)tropical countries but is increasingly reported in travelers as well. Diagnostic methods are cumbersome and require further improvement. Here, we describe leptospirosis among travelers presenting to the GeoSentinel Global Surveillance Network. We performed a descriptive analysis of leptospirosis cases reported in GeoSentinel from January 1997 through December 2016. We included 180 travelers with leptospirosis (mostly male; 74%; mostly tourists; 81%). The most frequent region of infection was Southeast Asia (52%); the most common source countries were Thailand (N = 52), Costa Rica (N = 13), Indonesia, and Laos (N = 11 each). Fifty-nine percent were hospitalized; one fatality was reported. We also distributed a supplemental survey to GeoSentinel sites to assess clinical and diagnostic practices. Of 56 GeoSentinel sites, three-quarters responded to the survey. Leptospirosis was reported to have been most frequently considered in febrile travelers with hepatic and renal abnormalities and a history of freshwater exposure. Serology was the most commonly used diagnostic method, although convalescent samples were reported to have been collected infrequently. Within GeoSentinel, leptospirosis was diagnosed mostly among international tourists and caused serious illness. Clinical suspicion and diagnostic workup among surveyed GeoSentinel clinicians were mainly triggered by a classical presentation and exposure history, possibly resulting in underdiagnosis. Suboptimal usage of available diagnostic methods may have resulted in additional missed, or misdiagnosed, cases.

Multistate US Outbreak of Rapidly Growing Mycobacterial Infections Associated with Medical Tourism to the Dominican Republic, 2013-2014(1)

Infections in 6 states were linked to persons traveling to undergo cosmetic surgical procedures.

During 2013, the Maryland Department of Health and Mental Hygiene in Baltimore, MD, USA, received report of 2 Maryland residents whose surgical sites were infected with rapidly growing mycobacteria after cosmetic procedures at a clinic (clinic A) in the Dominican Republic. A multistate investigation was initiated; a probable case was defined as a surgical site infection unresponsive to therapy in a patient who had undergone cosmetic surgery in the Dominican Republic. We identified 21 case-patients in 6 states who had surgery in 1 of 5 Dominican Republic clinics; 13 (62%) had surgery at clinic A. Isolates from 12 (92%) of those patients were culture-positive for Mycobacterium abscessus complex. Of 9 clinic A case-patients with available data, all required therapeutic surgical intervention, 8 (92%) were hospitalized, and 7 (78%) required ≥3 months of antibacterial drug therapy. Healthcare providers should consider infection with rapidly growing mycobacteria in patients who have surgical site infections unresponsive to standard treatment.

Business travel-associated illness: a GeoSentinel analysis

Background

Analysis of a large cohort of business travelers will help clinicians focus on frequent and serious illnesses. We aimed to describe travel-related health problems in business travelers.

Methods

GeoSentinel Surveillance Network consists of 64 travel and tropical medicine clinics in 29 countries; descriptive analysis was performed on ill business travelers, defined as persons traveling for work, evaluated after international travel 1 January 1997 through 31 December 2014.

Results

Among 12 203 business travelers seen 1997-2014 (14 045 eligible diagnoses), the majority (97%) were adults aged 20-64 years; most (74%) reported from Western Europe or North America; two-thirds were male. Most (86%) were outpatients. Fewer than half (45%) reported a pre-travel healthcare encounter. Frequent regions of exposure were sub-Saharan Africa (37%), Southeast Asia (15%) and South Central Asia (14%). The most frequent diagnoses were malaria (9%), acute unspecified diarrhea (8%), viral syndrome (6%), acute bacterial diarrhea (5%) and chronic diarrhea (4%). Species was reported for 973 (90%) of 1079 patients with malaria, predominantly Plasmodium falciparum acquired in sub-Saharan Africa. Of 584 (54%) with malaria chemoprophylaxis information, 92% took none or incomplete courses. Thirteen deaths were reported, over half of which were due to malaria; others succumbed to pneumonia, typhoid fever, rabies, melioidosis and pyogenic abscess.

Conclusions

Diarrheal illness was a major cause of morbidity. Malaria contributed substantial morbidity and mortality, particularly among business travelers to sub-Saharan Africa. Underuse or non-use of chemoprophylaxis contributed to malaria cases. Deaths in business travelers could be reduced by improving adherence to malaria chemoprophylaxis and targeted vaccination for vaccine-preventable diseases. Pre-travel advice is indicated for business travelers and is currently under-utilized and needs improvement.

Malaria after international travel: a GeoSentinel analysis, 2003-2016

BACKGROUND

More than 30,000 malaria cases are reported annually among international travellers. Despite improvements in malaria control, malaria continues to threaten travellers due to inaccurate perception of risk and sub-optimal pre-travel preparation.

METHODS

Records with a confirmed malaria diagnosis after travel from January 2003 to July 2016 were obtained from GeoSentinel, a global surveillance network of travel and tropical medicine providers that monitors travel-related morbidity. Records were excluded if exposure country was missing or unascertainable or if there was a concomitant acute diagnosis unrelated to malaria. Records were analyzed to describe the demographic and clinical characteristics of international travellers with malaria.

RESULTS

There were 5689 travellers included; 325 were children <18 years. More than half (53%) were visiting friends and relatives (VFRs). Most (83%) were exposed in sub-Saharan Africa. The median trip duration was 32 days (interquartile range 20-75); 53% did not have a pre-travel visit. More than half (62%) were hospitalized; children were hospitalized more frequently than adults (73 and 62%, respectively). Ninety-two per cent had a single Plasmodium species diagnosis, most frequently Plasmodium falciparum (4011; 76%). Travellers with P. falciparum were most frequently VFRs (60%). More than 40% of travellers with a trip duration ≤7 days had Plasmodium vivax. There were 444 (8%) travellers with severe malaria; 31 children had severe malaria. Twelve travellers died.

CONCLUSION

Malaria remains a serious threat to international travellers. Efforts must focus on preventive strategies aimed on children and VFRs, and chemoprophylaxis access and preventive measure adherence should be emphasized.

Elevation as a proxy for mosquito-borne Zika virus transmission in the Americas

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 quality, timely surveillance data made it difficult to confidently demarcate infection risk at a sub-national level. In the absence of reliable data on ZIKV activity, a pragmatic approach was needed to identify subnational geographic areas where the risk of ZIKV infection via mosquitoes was expected to be negligible. To address this urgent need, we evaluated elevation as a proxy for mosquito-borne ZIKV transmission.

Methods

For sixteen countries with local ZIKV transmission in the Americas, we analyzed (i) modelled occurrence of the primary vector for ZIKV, Aedes aegypti, (ii) human population counts, and (iii) reported historical dengue cases, specifically across 100-meter elevation levels between 1,500m and 2,500m. Specifically, we quantified land area, population size, and the number of observed dengue cases above each elevation level to identify a threshold where the predicted risks of encountering Ae. aegypti become negligible.

Results

Above 1,600m, less than 1% of each country’s total land area was predicted to have Ae. aegypti occurrence. Above 1,900m, less than 1% of each country’s resident population lived in areas where Ae. aegypti was predicted to occur. Across all 16 countries, 1.1% of historical dengue cases were reported above 2,000m.

Discussion

These results suggest low potential for mosquito-borne ZIKV transmission above 2,000m in the Americas. Although elevation is a crude predictor of environmental suitability for ZIKV transmission, its constancy made it a pragmatic input for policy decision-making during this public health emergency.

Clostridium difficile infection in returning travellers

Background

There is increasing recognition of the contribution of community-acquired cases to the global burden of Clostridium difficile infection (CDI). The epidemiology of CDI among international travellers is poorly understood, and factors associated with international travel, such as antibiotic use and changes in gut microbiota, could potentially put travellers at higher risk.

Methods

We summarized demographic, travel-associated and geographic characteristics of travellers with CDI in the GeoSentinel database from 1997 to 2015. We also surveyed GeoSentinel sites to compare various testing indications, approaches, and diagnostic modalities.

Results

We identified 260 GeoSentinel records, including 187 that satisfied criteria for analysis (confirmed cases in non-immigrant travellers aged >2 years, seen <12 weeks post-travel). CDI was reported in all age groups and in travellers to all world regions; the largest proportions of cases having destinations in Asia (31%), Central/South America or the Caribbean (30%) and Africa (24%). Our site survey revealed substantial heterogeneity of testing approaches between sites; the most commonly used test was the C. difficile toxin gene PCR.

Conclusions

CDI is encountered in returning international travellers, although there is considerable variability in testing practices. These data underscore the importance of awareness of C. difficile as a potential cause of travel-associated diarrhoea.

Characteristics of US Travelers to Zika Virus-Affected Countries in the Americas, March 2015-October 2016

Zika virus has recently been introduced to the Americas and is spreading rapidly. We evaluated the characteristics of US travelers to Zika virus–affected countries who were seen at Global TravEpiNet sites during March 2015–October 2016. Nearly three quarters of travelers were men or women of reproductive age.

Interagency and Commercial Collaboration During an Investigation of Chikungunya and Dengue Among Returning Travelers to the United States

Public health investigations can require intensive collaboration between numerous governmental and nongovernmental organizations. We describe an investigation involving several governmental and nongovernmental partners that was successfully planned and performed in an organized, comprehensive, and timely manner with several governmental and nongovernmental partners.

Travel-Associated Zika Virus Disease Acquired in the Americas Through February 2016: A GeoSentinel Analysis

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 clinics in 30 countries.

PATIENTS

Ill returned travelers with a confirmed, probable, or clinically suspected diagnosis of Zika virus disease seen between January 2013 and 29 February 2016.

MEASUREMENTS

Frequencies of demographic, trip, and clinical characteristics and complications.

RESULTS

Starting in May 2015, 93 cases of Zika virus disease were reported. Common symptoms included exanthema (88%), fever (76%), and arthralgia (72%). Fifty-nine percent of patients were exposed in South America; 71% were diagnosed in Europe. Case status was established most commonly by polymerase chain reaction (PCR) testing of blood and less often by PCR testing of other body fluids or serology and plaque-reduction neutralization testing. Two patients developed Guillain-Barré syndrome, and 3 of 4 pregnancies had adverse outcomes (microcephaly, major fetal neurologic abnormalities, and intrauterine fetal death).

LIMITATION

Surveillance data collected by specialized clinics may not be representative of all ill returned travelers, and denominator data are unavailable.

CONCLUSION

These surveillance data help characterize the clinical manifestations and adverse outcomes of Zika virus disease among travelers infected in the Americas and show a need for global standardization of diagnostic testing. The serious fetal complications observed in this study highlight the importance of travel advisories and prevention measures for pregnant women and their partners. Travelers are sentinels for global Zika virus circulation and may facilitate further transmission.

PRIMARY FUNDING SOURCE

Centers for Disease Control and Prevention, International Society of Travel Medicine, and Public Health Agency of Canada.

Profile of illness in Syrian refugees: A GeoSentinel analysis, 2013 to 2015

Screening of 488 Syrian unaccompanied minor refugees (< 18 years-old) in Berlin showed low prevalence of intestinal parasites (Giardia, 7%), positive schistosomiasis serology (1.4%) and absence of hepatitis B. Among 44 ill adult Syrian refugees examined at GeoSentinel clinics worldwide, cutaneous leishmaniasis affected one in three patients; other noteworthy infections were active tuberculosis (11%) and chronic hepatitis B or C (9%). These data can contribute to evidence-based guidelines for infectious disease screening of Syrian refugees.

Local and International Implications of Schistosomiasis Acquired in Corsica, France

We report 11 cases of schistosomiasis in international travelers who had bathed in rivers in Corsica, France, during 2012–2014. The infections were diagnosed in 2014 and reported to the GeoSentinel Surveillance Network and European Travel Medicine Network. Travelers can be sentinels for emerging infections; thus, this situation warrants a concerted human and veterinary epidemiologic response.

Chikungunya and Dengue Virus Infections Among United States Community Service Volunteers Returning from the Dominican Republic, 2014

Chikungunya spread throughout the Dominican Republic (DR) after the first identified laboratory-confirmed cases were reported in April 2014. In June 2014, a U.S.-based service organization operating in the DR reported chikungunya-like illnesses among several staff. We assessed the incidence of chikungunya virus (CHIKV) and dengue virus (DENV) infection and illnesses and evaluated adherence to mosquito avoidance measures among volunteers/staff deployed in the DR who returned to the United States during July-August 2014. Investigation participants completed a questionnaire that collected information on demographics, medical history, self-reported illnesses, and mosquito exposures and avoidance behaviors and provided serum for CHIKV and DENV diagnostic testing by reverse transcription polymerase chain reaction and IgM enzyme-linked immunosorbent assay. Of 102 participants, 42 (41%) had evidence of recent CHIKV infection and two (2%) had evidence of recent DENV infection. Of the 41 participants with evidence of recent CHIKV infection only, 39 (95%) reported fever, 37 (90%) reported rash, and 37 (90%) reported joint pain during their assignment. All attended the organization's health trainings, and 89 (87%) sought a pretravel health consultation. Most (∼95%) used insect repellent; however, only 30% applied it multiple times daily and < 5% stayed in housing with window/door screens. In sum, CHIKV infections were common among these volunteers during the 2014 chikungunya epidemic in the DR. Despite high levels of preparation, reported adherence to mosquito avoidance measures were inconsistent. Clinicians should discuss chikungunya with travelers visiting areas with ongoing CHIKV outbreaks and should consider chikungunya when diagnosing febrile illnesses in travelers returning from affected areas.

Measles in the 21st Century, a Continuing Preventable Risk to Travelers: Data From the GeoSentinel Global Network

Measles remains a risk for travelers, with 94 measles diagnoses reported to the GeoSentinel network from 2000 to 2014, two-thirds since 2010. Asia was the most common exposure region, then Africa and Europe. Efforts to reduce travel-associated measles should target all vaccine-eligible travelers, including catch-up vaccination of susceptible adults.

Animal-associated exposure to rabies virus among travelers, 1997-2012

No demographic characteristics identified who might benefit most from pretravel counseling.

Among travelers, rabies cases are rare, but animal bites are relatively common. To determine which travelers are at highest risk for rabies, we studied 2,697 travelers receiving care for animal-related exposures and requiring rabies postexposure prophylaxis at GeoSentinel clinics during 1997–2012. No specific demographic characteristics differentiated these travelers from other travelers seeking medical care, making it challenging to identify travelers who might benefit from reinforced pretravel rabies prevention counseling. Median travel duration was short for these travelers: 15 days for those seeking care after completion of travel and 20 days for those seeking care during travel. This finding contradicts the view that preexposure rabies vaccine recommendations should be partly based on longer travel durations. Over half of exposures occurred in Thailand, Indonesia, Nepal, China, and India. International travelers to rabies-endemic regions, particularly Asia, should be informed about potential rabies exposure and benefits of pretravel vaccination, regardless of demographics or length of stay.

Differential diagnosis of illness in travelers arriving from Sierra Leone, Liberia, or Guinea: a cross-sectional study from the GeoSentinel Surveillance Network

BACKGROUND

The largest-ever outbreak of Ebola virus disease (EVD), ongoing in West Africa since late 2013, has led to export of cases to Europe and North America. Clinicians encountering ill travelers arriving from countries with widespread Ebola virus transmission must be aware of alternate diagnoses associated with fever and other nonspecific symptoms.

OBJECTIVE

To define the spectrum of illness observed in persons returning from areas of West Africa where EVD transmission has been widespread.

DESIGN

Descriptive, using GeoSentinel records.

SETTING

57 travel or tropical medicine clinics in 25 countries.

PATIENTS

805 ill returned travelers and new immigrants from Sierra Leone, Liberia, or Guinea seen between September 2009 and August 2014.

MEASUREMENTS

Frequencies of demographic and travel-related characteristics and illnesses reported.

RESULTS

The most common specific diagnosis among 770 nonimmigrant travelers was malaria (n = 310 [40.3%]), with Plasmodium falciparum or severe malaria in 267 (86%) and non-P. falciparum malaria in 43 (14%). Acute diarrhea was the second most common diagnosis among nonimmigrant travelers (n = 95 [12.3%]). Such common diagnoses as upper respiratory tract infection, urinary tract infection, and influenza-like illness occurred in only 26, 9, and 7 returning travelers, respectively. Few instances of typhoid fever (n = 8), acute HIV infection (n = 5), and dengue (n = 2) were encountered.

LIMITATION

Surveillance data collected by specialist clinics may not be representative of all ill returned travelers.

CONCLUSION

Although EVD may currently drive clinical evaluation of ill travelers arriving from Sierra Leone, Liberia, and Guinea, clinicians must be aware of other more common, potentially fatal diseases. Malaria remains a common diagnosis among travelers seen at GeoSentinel sites. Prompt exclusion of malaria and other life-threatening conditions is critical to limiting morbidity and mortality.

PRIMARY FUNDING SOURCE

Centers for Disease Control and Prevention.

Travel-associated disease among US residents visiting US GeoSentinel clinics after return from international travel

BACKGROUND

US residents make 60 million international trips annually. Family practice providers need to be aware of travel-associated diseases affecting this growing mobile population.

OBJECTIVE

To describe demographics, travel characteristics and clinical diagnoses of US residents who present ill after international travel.

METHODS

Descriptive analysis of travel-associated morbidity and mortality among US travellers seeking care at 1 of the 22 US practices and clinics participating in the GeoSentinel Global Surveillance Network from January 2000 to December 2012.

RESULTS

Of the 9624 ill US travellers included in the analysis, 3656 (38%) were tourist travellers, 2379 (25%) missionary/volunteer/research/aid workers (MVRA), 1580 (16%) travellers visiting friends and relatives (VFRs), 1394 (15%) business travellers and 593 (6%) student travellers. Median (interquartile range) travel duration was 20 days (10-60 days). Pre-travel advice was sought by 45%. Hospitalization was required by 7%. Compared with other groups of travellers, ill MVRA travellers returned from longer trips (median duration 61 days), while VFR travellers disproportionately required higher rates of inpatient care (24%) and less frequently had received pre-travel medical advice (20%). Illnesses of the gastrointestinal tract were the most common (58%), followed by systemic febrile illnesses (18%) and dermatologic disorders (17%). Three deaths were reported. Diagnoses varied according to the purpose of travel and region of exposure.

CONCLUSIONS

Returning ill US international travellers present with a broad spectrum of travel-associated diseases. Destination and reason for travel may help primary health care providers to generate an accurate differential diagnosis for the most common disorders and for those that may be life-threatening.

Acute muscular sarcocystosis: an international investigation among ill travelers returning from Tioman Island, Malaysia, 2011-2012

BACKGROUND

Through 2 international traveler-focused surveillance networks (GeoSentinel and TropNet), we identified and investigated a large outbreak of acute muscular sarcocystosis (AMS), a rarely reported zoonosis caused by a protozoan parasite of the genus Sarcocystis, associated with travel to Tioman Island, Malaysia, during 2011-2012.

METHODS

Clinicians reporting patients with suspected AMS to GeoSentinel submitted demographic, clinical, itinerary, and exposure data. We defined a probable case as travel to Tioman Island after 1 March 2011, eosinophilia (>5%), clinical or laboratory-supported myositis, and negative trichinellosis serology. Case confirmation required histologic observation of sarcocysts or isolation of Sarcocystis species DNA from muscle biopsy.

RESULTS

Sixty-eight patients met the case definition (62 probable and 6 confirmed). All but 2 resided in Europe; all were tourists and traveled mostly during the summer months. The most frequent symptoms reported were myalgia (100%), fatigue (91%), fever (82%), headache (59%), and arthralgia (29%); onset clustered during 2 distinct periods: "early" during the second and "late" during the sixth week after departure from the island. Blood eosinophilia and elevated serum creatinine phosphokinase (CPK) levels were observed beginning during the fifth week after departure. Sarcocystis nesbitti DNA was recovered from 1 muscle biopsy.

CONCLUSIONS

Clinicians evaluating travelers returning ill from Malaysia with myalgia, with or without fever, should consider AMS, noting the apparent biphasic aspect of the disease, the later onset of elevated CPK and eosinophilia, and the possibility for relapses. The exact source of infection among travelers to Tioman Island remains unclear but needs to be determined to prevent future illnesses.

Rabies in nonhuman primates and potential for transmission to humans: a literature review and examination of selected French national data

BACKGROUND

The nonhuman primate (NHP)-related injuries in rabies-enzootic countries is a public health problem of increasing importance. The aims of this work are to collect data concerning rabies transmission from NHPs to humans; to collate medical practices regarding rabies postexposure prophylaxis (PEP) in different countries, and to provide an evidence base to support the decision to apply rabies PEP in this context.

METHODOLOGY

To retrieve information, we conducted a literature search from 1960 to January 2013. All reports of rabies in NHPs and rabies transmission to humans by infected NHPs were included. Also included were studies of travelers seeking care for rabies PEP in various settings. Data collected by the French National Reference Centre for Rabies concerning NHPs submitted for rabies diagnosis in France and human rabies exposure to NHPs in travelers returning to France were analyzed for the periods 1999-2012 and 1994-2011, respectively.

PRINCIPAL FINDINGS

A total of 159 reports of rabies in NHPs have been retrieved from various sources in South America, Africa, and Asia, including 13 cases in animals imported to Europe and the US. 134 were laboratory confirmed cases. 25 cases of human rabies following NHP-related injuries were reported, including 20 from Brazil. Among more than 2000 international travelers from various settings, the proportion of injuries related to NHP exposures was about 31%. NHPs rank second, following dogs in most studies and first in studies conducted in travelers returning from Southeast Asia. In France, 15.6% of 1606 travelers seeking PEP for exposure to any animal were injured by monkeys.

CONCLUSIONS/SIGNIFICANCE

Although less frequently reported in published literature than human rabies, confirmed rabies cases in NHPs occur. The occurrence of documented transmission of rabies from NHPs to human suggests that rabies PEP is indicated in patients injured by NHPs in rabies-enzootic countries.

Notes from the field: rapidly growing nontuberculous Mycobacterium wound infections among medical tourists undergoing cosmetic surgeries in the Dominican Republic--multiple states, March 2013-February 2014

In August 2013, the Maryland Department of Health and Mental Hygiene (MDHMH) was notified of two persons with rapidly growing nontuberculous mycobacterial (RG-NTM) surgical-site infections. Both patients had undergone surgical procedures as medical tourists at the same private surgical clinic (clinic A) in the Dominican Republic the previous month. Within 7 days of returning to the United States, both sought care for symptoms that included surgical wound abscesses, clear fluid drainage, pain, and fever. Initial antibiotic therapy was ineffective. Material collected from both patients' wounds grew Mycobacterium abscessus exhibiting a high degree of antibiotic resistance characteristic of this organism.

Diarrheal illness among US residents providing medical services in Haiti during the cholera epidemic, 2010 to 2011

Although nosocomial transmission of cholera is rare, two US healthcare workers (HCW) became ill with cholera after providing medical services during the Haiti cholera epidemic. To assess the incidence of diarrheal illness and explore preventive health behaviors practiced by US residents who provided medical services in Haiti, we conducted a cross-sectional, anonymous, web-based survey. We e-mailed 896 participants from 50 US-based, health-focused non-governmental organizations (NGOs), of whom 381 (43%) completed the survey. Fifty-six percent of respondents (n = 215) reported providing some care for patients with cholera. Diarrhea was reported by 31 (8%) respondents. One person was diagnosed with cholera by serologic testing. NGOs responding to international emergencies should ensure ample access to basic hygiene supplies and should promote their use to reduce the incidence of diarrheal illness among HCW working overseas.

Analyzing GeoSentinel surveillance data: a comparison of methods to explore acute gastrointestinal illness among international travelers

GeoSentinel is a global surveillance network of travel medicine clinics that collect data from ill international travelers. Analyses have relied on proportionate morbidity calculations, but proportionate morbidity cannot estimate disease risk because healthy travelers are not included in the denominator. The authors evaluated the use of a case-control design, controlling for GeoSentinel site and date of clinic visit, to calculate a reporting odds ratio (ROR). The association between region of travel and acute gastrointestinal illness was evaluated. All analyses found that the association with acute gastrointestinal illness was greatest among those who traveled to North Africa and South-Central Asia. There was consistency in the magnitude of the ROR and proportionate morbidity ratio (PMR) in regions such as the Caribbean. However, in other regions, the matched ROR was noticeably different than the PMR. The case-control ROR may be preferred for single-disease/syndrome analytical studies using GeoSentinel surveillance data or other surveillance data.

Surveillance for travel-related disease--GeoSentinel Surveillance System, United States, 1997-2011

PROBLEM/CONDITION

In 2012, the number of international tourist arrivals worldwide was projected to reach a new high of 1 billion arrivals, a 48% increase from 674 million arrivals in 2000. International travel also is increasing among U.S. residents. In 2009, U.S. residents made approximately 61 million trips outside the country, a 5% increase from 1999. Travel-related morbidity can occur during or after travel. Worldwide, 8% of travelers from industrialized to developing countries report becoming ill enough to seek health care during or after travel. Travelers have contributed to the global spread of infectious diseases, including novel and emerging pathogens. Therefore, surveillance of travel-related morbidity is an essential component of global public health surveillance and will be of greater importance as international travel increases worldwide.

REPORTING PERIOD

September 1997-December 2011.

DESCRIPTION OF SYSTEM

GeoSentinel is a clinic-based global surveillance system that tracks infectious diseases and other adverse health outcomes in returned travelers, foreign visitors, and immigrants. GeoSentinel comprises 54 travel/tropical medicine clinics worldwide that electronically submit demographic, travel, and clinical diagnosis data for all patients evaluated for an illness or other health condition that is presumed to be related to international travel. Clinical information is collected by physicians with expertise or experience in travel/tropical medicine. Data collected at all sites are entered electronically into a database, which is housed at and maintained by CDC. The GeoSentinel network membership program comprises 235 additional clinics in 40 countries on six continents. Although these network members do not report surveillance data systematically, they can report unusual or concerning diagnoses in travelers and might be asked to perform enhanced surveillance in response to specific health events or concerns.

RESULTS

During September 1997-December 2011, data were collected on 141,789 patients with confirmed or probable travel-related diagnoses. Of these, 23,006 (16%) patients were evaluated in the United States, 10,032 (44%) of whom were evaluated after returning from travel outside of the United States (i.e., after-travel patients). Of the 10,032 after-travel patients, 4,977 (50%) were female, 4,856 (48%) were male, and 199 (2%) did not report sex; the median age was 34 years. Most were evaluated in outpatient settings (84%), were born in the United States (76%), and reported current U.S. residence (99%). The most common reasons for travel were tourism (38%), missionary/volunteer/research/aid work (24%), visiting friends and relatives (17%), and business (15%). The most common regions of exposure were Sub-Saharan Africa (23%), Central America (15%), and South America (12%). Fewer than half (44%) reported having had a pretravel visit with a health-care provider. Of the 13,059 diagnoses among the 10,032 after-travel patients, the most common diagnoses were acute unspecified diarrhea (8%), acute bacterial diarrhea (5%), postinfectious irritable bowel syndrome (5%), giardiasis (3%), and chronic unknown diarrhea (3%). The most common diagnostic groupings were acute diarrhea (22%), nondiarrheal gastrointestinal (15%), febrile/systemic illness (14%), and dermatologic (12%). Among 1,802 patients with febrile/systemic illness diagnoses, the most common diagnosis was Plasmodium falciparum malaria (19%). The rapid communication component of the GeoSentinel network has allowed prompt responses to important health events affecting travelers; during 2010 and 2011, the notification capability of the GeoSentinel network was used in the identification and public health response to East African trypanosomiasis in Eastern Zambia and North Central Zimbabwe, P. vivax malaria in Greece, and muscular sarcocystosis on Tioman Island, Malaysia.

INTERPRETATION

The GeoSentinel Global Surveillance System is the largest repository of provider-based data on travel-related illness. Among ill travelers evaluated in U.S. GeoSentinel sites after returning from international travel, gastrointestinal diagnoses were most frequent, suggesting that U.S. travelers might be exposed to unsafe food and water while traveling internationally. The most common febrile/systemic diagnosis was P. falciparum malaria, suggesting that some U.S. travelers to malarial areas are not receiving or using proper malaria chemoprophylaxis or mosquito-bite avoidance measures. The finding that fewer than half of all patients reported having made a pretravel visit with a health-care provider indicates that a substantial portion of U.S. travelers might not be following CDC travelers' health recommendations for international travel.

PUBLIC HEALTH ACTION

GeoSentinel surveillance data have helped researchers define an evidence base for travel medicine that has informed travelers' health guidelines and the medical evaluation of ill international travelers. These data suggest that persons traveling internationally from the United States to developing countries remain at risk for illness. Health-care providers should help prepare travelers properly for safe travel and provide destination-specific medical evaluation of returning ill travelers. Training for health-care providers should focus on preventing and treating a variety of travel-related conditions, particularly traveler's diarrhea and malaria.

GeoSentinel surveillance of illness in returned travelers, 2007-2011

BACKGROUND

International travel continues to increase, particularly to Asia and Africa. Clinicians are increasingly likely to be consulted for advice before travel or by ill returned travelers.

OBJECTIVE

To describe typical diseases in returned travelers according to region, travel reason, and patient demographic characteristics; describe the pattern of low-frequency travel-associated diseases; and refine key messages for care before and after travel.

DESIGN

Descriptive, using GeoSentinel records.

SETTING

53 tropical or travel disease units in 24 countries.

PATIENTS

42 173 ill returned travelers seen between 2007 and 2011.

MEASUREMENTS

Frequencies of demographic characteristics, regions visited, and illnesses reported.

RESULTS

Asia (32.6%) and sub-Saharan Africa (26.7%) were the most common regions where illnesses were acquired. Three quarters of travel-related illness was due to gastrointestinal (34.0%), febrile (23.3%), and dermatologic (19.5%) diseases. Only 40.5% of all ill travelers reported pretravel medical visits. The relative frequency of many diseases varied with both travel destination and reason for travel, with travelers visiting friends and relatives in their country of origin having both a disproportionately high burden of serious febrile illness and very low rates of advice before travel (18.3%). Life-threatening diseases, such as Plasmodium falciparum malaria, melioidosis, and African trypanosomiasis, were reported.

LIMITATIONS

Sentinel surveillance data collected by specialist clinics do not reflect healthy returning travelers or those with mild or self-limited illness. Data cannot be used to infer quantitative risk for illness.

CONCLUSION

Many illnesses may have been preventable with appropriate advice, chemoprophylaxis, or vaccination. Clinicians can use these 5-year GeoSentinel data to help tailor more efficient pretravel preparation strategies and evaluate possible differential diagnoses of ill returned travelers according to destination and reason for travel.

PRIMARY FUNDING SOURCE

Centers for Disease Control and Prevention.

Ongoing outbreak of an acute muscular Sarcocystis-like illness among travellers returning from Tioman Island, Malaysia, 2011-2012

As of 4 November, 2012, 100 patients with an acute muscular Sarcocystis-like illness associated with travel to Tioman Island, Malaysia, have been identified. Thirty-five travelled there mostly during July and August 2011 and 65 mostly during July and August 2012, suggesting an ongoing outbreak. Epidemiological investigations are ongoing. Public health agencies and practicing clinicians should be aware of this rarely-reported disease in humans and consider it as differential diagnosis in travellers returning from Tioman Island.

Ongoing outbreak of an acute muscular Sarcocystis-like illness among travellers returning from Tioman Island, Malaysia, 2011-2012

As of 4 November, 2012, 100 patients with an acute muscular Sarcocystis-like illness associated with travel to Tioman Island, Malaysia, have been identified. Thirty-five travelled there mostly during July and August 2011 and 65 mostly during July and August 2012, suggesting an ongoing outbreak. Epidemiological investigations are ongoing. Public health agencies and practicing clinicians should be aware of this rarely-reported disease in humans and consider it as differential diagnosis in travellers returning from Tioman Island.

Impact of rotavirus vaccine on diarrhea-associated disease burden among American Indian and Alaska Native children

OBJECTIVE

Beginning in 2006, the Indian Health Service (IHS) began rotavirus vaccination of American Indian and Alaska Native (AI/AN) infants. To assess vaccine impact, we examined trends in IHS diarrhea-associated hospitalization and outpatient visits among AI/AN children in the pre- and postrotavirus vaccine era.

METHODS

Diarrhea-associated hospitalizations and outpatient visits among AI/AN children <5 years of age during 2001 through 2010 were examined by gender, age group, and region for prevaccine years 2001-2006 and postvaccine years 2008, 2009, and 2010. To account for secular declining trends observed in prevaccine years, expected diarrhea-associated hospitalization and outpatient rates for postvaccine years were generated by using Poisson regression analysis of the 2001-2006 annual rates.

RESULTS

Coverage with at least 1 dose of rotavirus vaccine among AI/AN infants aged 3 to 5 months in the first half of 2008, 2009, and 2010 ranged from 48% to 80% in various IHS regions. The prevaccine average annual diarrhea-associated hospitalization rates among AI/AN children <5 years of age was 63 per 10 000 persons (range: 57-75 per 10 000), and declined to 39, 31, and 27 per 10 000 in 2008, 2009, and 2010, respectively. Observed 2008, 2009, and 2010 rates were 24%, 37%, and 44% lower than expected rates, respectively. Decreases in diarrhea-associated hospitalizations and outpatient visits were observed in all IHS regions.

CONCLUSIONS

Diarrhea-associated hospitalization and outpatient visit rates among AI/AN children have declined after implementation of rotavirus vaccination in AI/AN populations.

Serologically confirmed household transmission of 2009 pandemic influenza A (H1N1) virus during the first pandemic wave--New York City, April-May 2009

BACKGROUND

Understanding transmissibility of influenza viruses within households is critical for guiding public health response to pandemics. We studied serologically confirmed infection and disease among household contacts of index case patients with 2009 pandemic influenza A (H1N1) virus (pH1N1) infection in a setting of minimal community pH1N1 transmission.

METHODS

We defined index case patients as students and staff of a New York City high school with laboratory-confirmed pH1N1 infection during the earliest phase of the pH1N1 outbreak in April 2009. We visited households of index case patients twice, once in early May and again in June/July 2009. At each visit, household members (both index case patents and household contacts) provided serum samples and completed questionnaires about illness and possible risk factors. Serologic testing was performed using microneutralization and hemagglutination-inhibition assays.

RESULTS

Of 79 eligible household contacts in 28 households, 19% had serologically confirmed pH1N1 infection, and 28% of those infected were asymptomatic. Serologically confirmed infection varied by age among household contacts: 36% of contacts younger than 10 years were infected, compared with 46% of contacts age 10-18 years, 8% of contacts aged 19-54 years, and 22% of contacts aged 55 years and older.

CONCLUSIONS

Infection rates were high for household contacts of persons with confirmed pH1N1, particularly for contacts aged 10-18 years, and asymptomatic infection was common. Efforts to reduce household transmission during influenza pandemics are important adjuncts to strategies to reduce community illness.

Characteristics and spectrum of disease among ill returned travelers from pre- and post-earthquake Haiti: The GeoSentinel experience

To describe patient characteristics and disease spectrum among foreign visitors to Haiti before and after the 2010 earthquake, we used GeoSentinel Global Surveillance Network data and compared 1 year post-earthquake versus 3 years pre-earthquake. Post-earthquake travelers were younger, predominantly from the United States, more frequently international assistance workers, and more often medically counseled before their trip than pre-earthquake travelers. Work-related stress and upper respiratory tract infections were more frequent post-earthquake; acute diarrhea, dengue, and Plasmodium falciparum malaria were important contributors of morbidity both pre- and post-earthquake. These data highlight the importance of providing destination- and disaster-specific pre-travel counseling and post-travel evaluation and medical management to persons traveling to or returning from a disaster location, and evaluations should include attention to the psychological wellbeing of these travelers. For travel to Haiti, focus should be on mosquito-borne illnesses (dengue and P. falciparum malaria) and travelers' diarrhea.

Baseline estimates of diarrhea-associated mortality among United States children before rotavirus vaccine introduction

OBJECTIVES

Deaths due to diarrhea among US children declined substantially from the 1960s through the 1980s, but have not been recently assessed. We examined diarrhea-associated mortality among young US children from 1992 to 2006 to establish baseline estimates through which the effect of rotavirus vaccines, introduced in 2006, can be assessed.

METHODS

National Center for Health Statistics multiple cause-of-death mortality data were used to examine diarrhea-associated deaths and death rates among US children 1 to 59 months of age during 1992-2006. The winter residual method was used to indirectly estimate the annual number of diarrhea-associated deaths attributable to rotavirus.

RESULTS

An average of 369 diarrhea-associated deaths/year (3320 total deaths) occurred among US children 1 to 59 months of age during 1992-1998 and 2005-2006. The diarrhea-associated death rate increased 40% between the first 3 and last 2 years of the study period, from an average of 1.6 deaths per 100,000 to 2.3 deaths per 100,000. Black children died at almost 4 times the rate of white children. Diarrhea-associated deaths showed a winter seasonal pattern similar to that of rotavirus, particularly among children 4 to 23 months of age. Using indirect methods, we estimated 25 yearly rotavirus-associated deaths during the study period. Rotavirus vaccination could potentially prevent 21 of these deaths annually.

CONCLUSIONS

Diarrhea-associated mortality among US children stabilized but appears to be increasing in recent years. Rotavirus was associated with a small but significant number of preventable deaths. The national multiple cause-of-death data should prove useful for assessing mortality impact of rotavirus vaccination in the United States.

Projected impact and cost-effectiveness of a rotavirus vaccination program in India, 2008

BACKGROUND

To assess the value of rotavirus vaccination in India, we determined the potential impact and cost-effectiveness of a national rotavirus vaccination program.

METHODS

We compared the national rotavirus disease and cost burden with and without a vaccination program and assessed the cost-effectiveness of vaccination. Model inputs included measures of disease and cost burden, vaccine performance, and vaccination coverage and cost. We measured the annual number of health-related events and treatment costs averted, as well as the cost-effectiveness in US dollars per disability-adjusted life-year (DALY) and cost per death averted. One-way sensitivity analyses were performed by individually varying each model input.

RESULTS

With use of a vaccine that has an estimated effectiveness of 50%, a rotavirus vaccination program in India would prevent ~44,000 deaths, ~293,000 hospitalizations, and ~328,000 outpatient visits annually, which would avert $20.6 million in medical treatment costs. Vaccination would be cost-saving at the GAVI Alliance price of $0.15 per dose. At $1.00 per dose, a vaccination program would cost $49.8 million, which would result in an expenditure of $21.41 per DALY averted or $662.94 per life saved. Even at $7.00 per dose, vaccination would be highly cost-effective. In sensitivity analyses, varying efficacy against severe rotavirus disease and vaccine price had the greatest impact on cost-effectiveness.

CONCLUSIONS

A national rotavirus vaccination program in India would prevent substantial rotavirus morbidity and mortality and would be highly cost-effective at a range of vaccine prices. Public health officials can use this locally derived data to evaluate how this highly cost-effective intervention might fit into India's long-term health care goals.

Sustained decline in rotavirus detections in the United States following the introduction of rotavirus vaccine in 2006

BACKGROUND

Following implementation of the rotavirus vaccination program in 2006, rotavirus activity in the United States declined dramatically in 2007-2008 but increased slightly in 2008-2009, despite greater vaccine uptake. To further evaluate impact of the vaccine program, we assessed trends in rotavirus testing and detection during 2009-2010.

METHODS

We examined rotavirus testing data from July 2000 to June 2010 from the National Respiratory and Enteric Viruses Surveillance System to compare rotavirus season timing and peak activity in the pre- and postvaccine introduction eras. Rotavirus season onset was defined as the first of 2 consecutive weeks during which the percentage of specimens testing positive for rotavirus was ≥ 10%. To assess trends in rotavirus testing and detection, we restricted the analyses to 25 laboratories that reported for ≥ 26 weeks per season from 2000 to 2010.

RESULTS

During 2009-2010, the threshold for the start of the rotavirus season was never achieved nationally or in the North, Midwest, or West. Activity in the South met this threshold but the season duration was substantially shorter and of lower magnitude than in all previous pre- and postvaccine introduction seasons. Nationally and within each region, the peak week was more delayed and the peak proportion of positive tests was substantially lower than all previous seasons. The total number of tests performed declined by 23%, and the number of positive tests declined by 86%.

CONCLUSIONS

Rotavirus activity was substantially diminished during the 2009-2010 rotavirus season compared with the prevaccine baseline and the 2 previous postvaccine introduction seasons. These sustained declines over 3 rotavirus seasons reaffirm the health benefits of the US rotavirus vaccination program.

Outbreak of pneumonia associated with emergent human adenovirus serotype 14--Southeast Alaska, 2008

BACKGROUND

In September 2008, an outbreak of pneumonia associated with an emerging human adenovirus (human adenovirus serotype 14 [HAdV-14]) occurred on a rural Southeast Alaska island. Nine patients required hospitalization, and 1 patient died.

METHODS

To investigate the outbreak, pneumonia case patients were matched to control participants on the basis of age, sex, and community of residence. Participants in the investigation and their household contacts were interviewed, and serum samples and respiratory tract specimens were collected. Risk factors were evaluated by means of conditional logistic regression.

RESULTS

Among 32 pneumonia case patients, 21 (65%) had confirmed or probable HAdV-14 infection. None of 32 matched control participants had evidence of HAdV-14 infection (P<.001 for the difference). Factors independently associated with pneumonia included contact with a known HAdV-14-infected case patient (odds ratio [OR], 18.3 [95% confidence interval {CI}, >or=2.0]), current smoking (OR, 6.7 [95% CI, >or=0.9]), and having neither traveled off the island nor attended a large public gathering (OR, 14.7 [95% CI, >or=2.0]). Fourteen (67%) of 21 HAdV-14-positive case patients belonged to a single network of people who socialized and often smoked together and infrequently traveled off the island. HAdV-14 infection occurred in 43% of case-patient household contacts, compared with 5% of control-participant household contacts (P = .005).

CONCLUSIONS

During a community outbreak in Alaska, HAdV-14 appeared to have spread mostly among close contacts and not widely in the community. Demographic characteristics and illness patterns among the case patients were similar to those observed in other recent outbreaks of HAdV-14 infection in the United States.

Effectiveness of rotavirus vaccination against childhood diarrhoea in El Salvador: case-control study

OBJECTIVE

To evaluate the effectiveness of a monovalent rotavirus vaccine against severe rotavirus disease and to assess its impact on diarrhoea in children aged less than 2 years after national introduction in El Salvador, a low-middle income country in Central America.

DESIGN

Matched case-control study.

SETTING

Seven hospitals in cities across El Salvador, January 2007 to June 2009.

PARTICIPANTS

323 children aged less than 2 years admitted with laboratory confirmed rotavirus diarrhoea and 969 healthy controls matched for age and neighbourhood.

MAIN OUTCOME MEASURE

Effectiveness of rotavirus vaccination ((1-adjusted odds ratio of vaccination)x100) against rotavirus diarrhoea requiring hospital admission.

RESULTS

Cases and controls were similar for breast feeding, premature birth, maternal education, and socioeconomic variables. G1P[8] strains were identified in 92% of rotavirus cases. Effectiveness of two doses of vaccination against diarrhoea requiring hospital admission was 76% (95% confidence interval 64% to 84%). Protection was significantly lower (P=0.046) among children aged 12 months or more (59%, 27% to 77%) compared with children aged 6-11 months (83%, 68% to 91%). One dose of vaccine was 51% (26% to 67%) effective. At the sentinel hospitals, all admissions for diarrhoea among children under 5 declined by 40% in 2008 and by 51% in 2009 from the prevaccine year 2006.

CONCLUSIONS

A monovalent rotavirus vaccine was highly effective against admissions for rotavirus diarrhoea in children aged less than 2 years in El Salvador and substantially reduced the number of such admissions in this low-middle income setting. The impact on disease epidemiology after vaccination, particularly among older children, warrants future attention.

Tyrosine phosphorylation of the delta-opioid receptor. Evidence for its role in mitogen-activated protein kinase activation and receptor internalization*

The internalization of G-protein-coupled receptors (GPCRs), including the delta opioid receptor (delta-OR), has been shown to involve the phosphorylation of serine and threonine residues. However, recent studies suggest that these residues may not be the only ones phosphorylated in response to prolonged opioid exposure. Tyrosines also appear important for delta-OR signalling, but it remains unclear whether they undergo phosphorylation. We examined whether the delta-OR, stably expressed in Chinese hamster ovary (CHO-K1) cells, was tyrosine-phosphorylated during prolonged agonist treatment. The epitope-tagged delta-OR was purified by immunoprecipitation, and the presence of phosphorylated tyrosines was detected using anti-phosphotyrosine antibodies. Tyrosine residues in the delta-OR were phosphorylated after exposure to the high-affinity agonist [d-Thr(2)]-Leu-enkephalin-Thr (DTLET) in a time- and concentration-dependent manner. Tyrosine phosphorylation of the delta-OR appeared to require the actions of a Src-like protein tyrosine kinase, since the Src inhibitor 4-amino-5-(4-methylphenyl)-7-(t-butyl)-pyrazolo-[3,4-d]-pyrimidine (PP1) attenuated this response. PP1 also attenuated the DTLET-mediated activation of mitogen-activated protein kinase, as well as rapid delta-OR internalization, but not receptor down-regulation. Finally, only opioid agonists that induce receptor internalization via the clathrin-dependent endosomal pathway stimulated significant tyrosine phosphorylation of the delta-OR protein. Evidence is presented that the delta-OR is tyrosine-phosphorylated, and we suggest how this may have an active role in opioid receptor signalling and regulation.

Mutation of tyrosine 318 (Y318F) in the delta-opioid receptor attenuates tyrosine phosphorylation, agonist-dependent receptor internalization, and mitogen-activated protein kinase activation

Opioid receptors are known for their ability to activate diverse second messenger systems. Previously, we showed that selective delta-opioid agonists were able to induce the rapid tyrosine phosphorylation of delta-opioid receptors (delta-ORs) through Src. Src-dependent tyrosine phosphorylation of delta-ORs appears to be important for activation of the mitogen-activated protein kinase cascade and for receptor sequestration into clathrin-coated endosomes, as the Src antagonist, PP1, inhibited both. In an attempt to clarify the role of tyrosine phosphorylation in delta-OR signalling and regulation, we constructed a mutant receptor in which the tyrosine located in the conserved NPXXY motif of the C-terminus was replaced by a phenylalanine (Y318F-delta-OR). Mutation of Y318 resulted in a receptor that was comparable to the wild type in its expression level in HEK-293 cells and in its affinity for opioid ligands. Both receptors showed effective coupling to G proteins and were capable of inhibiting forskolin-stimulated cAMP accumulation with similar potencies. However, the mutant receptor was able to stimulate (35)S-GTPgammaS binding with a lower EC(50) than the wild type receptor. The stimulation of tyrosine phosphorylation in delta-ORs by [D-Thr(2)]-Leu-enkephalin-Thr (DTLET) was significantly less in cells expressing the Y318F-delta-OR than in cells expressing the wild type. In addition, both rapid receptor internalization and down-regulation were markedly attenuated in the mutant. Finally, the mutant receptor was unable to induce a robust activation of the MAPK pathway, suggesting that tyrosine phosphorylation of the delta-OR protein is important for this signalling pathway. These findings implicate tyrosine phosphorylation of Y318 in receptor signalling and agonist-mediated regulation.

The epidemiology of tuberculosis among North Carolina migrant farm workers

Although tuberculosis (TB) has been recognized as a significant health problem of migrant farm workers, the nature and extent of the problem have been poorly defined. We report the first population-based study of TB in a random sample of farm workers (n = 543) and the first use of recall antigens in an epidemiologic study of TB. Purified protein derivative positivity ranged from 33% in Hispanics to 54% in US-born blacks and 76% in Haitians. Active tubercular disease occurred in 3.6% of US-born blacks and 0.47% of Hispanics. Among US-born blacks, risk factors associated with farm work were most significant. Blacks born in the United States also had the highest prevalence of anergy. The use of recall antigens made possible a better description of the epidemiology of TB by excluding false negatives and clarifying associations between infection and risk factors. We conclude that TB among farm workers represents a serious public health problem with previously unrecognized risk factors. Additional resources for migrant health care, improvements in health care access, and fundamental changes in the system of migrant labor are all necessary to reduce the transmission of TB.