Typhoid fever in group travelers: opportunity for studying vaccine efficacy

BACKGROUND: Typhoid fever (TF) is a rare disease among travelers to endemic areas, and little is known about its travel-related epidemiology. In addition, efficacy data on TF vaccines in travelers is scanty. During 3 months of 1994/95, six cases of TF were reported in The Netherlands among participants of four package tours to Indonesia provided by the same operator. The present study was designed to describe the epidemiology of TF in these groups, and to assess whether travel groups can be used for studying the efficacy of TF vaccines in travelers. METHOD: Questionnaire-based historical cohort study of participants of 4 groups that stayed in the same hotels along their tours (n=156). TF was defined as blood culture-confirmed Salmonella typhi infection. Submitted isolates were typed by antigen and phage typing. Immunization status was considered documented if ascertained by written records. RESULTS: Among 110 participants (71%), six cases of TF were identified (group specific attack rate AR 5.4%), three of which were from one travel group (AR 12.0%). There were no significant differences by age or sex. Three submitted S. typhi isolates showed three different types, two of which were in the same group. Eighty-three percent of respondents reported documented TF vaccination in the preceding 3 years. All cases occurred in recipients of the oral Ty21a vaccine (AR 10.2%, 95% CI 3.8-20.8%), but differences with nonvaccinees and recipients of the heat-inactivated whole cell or Vi-antigen polysaccharide vaccines were not significant. CONCLUSIONS: Although TF is rare in travelers, infections with different strains of S. typhi can occur in one travel group. Travel groups offer an opportunity for retrospective assessment of vaccine efficacy, provided that equal chance of exposure is largely guaranteed; case ascertainment is maximally specific and similar in the vaccine groups; vaccine status is ascertained accurately; and prior immunity by previous exposures to and use of antibiotics effective against the infection are excluded from, or controlled for in, the analysis.     

Incidence and precipitating factors of morbidity among Israeli travelers abroad

BACKGROUND: During recent years international travel, including visits to the developing world, has become increasingly popular. Many of these travelers suffer from some sort of health problem during their trip or after their return. Travelers clinics that give pretravel immunization and counseling have emerged. This study analyzes the incidence and risk factors for health problems among Israelis traveling abroad. METHODS: The study surveyed by telephone 200 people who visited the traveler's clinic at Soroka Medical Center in Beer-Sheva during the years 1998 to 1999. The travelers were questioned after returning from their journey about the type and duration of the trip, compliance with medical advice given in the travel clinic, and health problems during the trip. RESULTS: The mean age was 26.4 +/- 9.4 years, 7% went on an organized tour, 23% traveled alone, and 77% traveled with a friend. The mean duration of the trip was 14.7 +/- 13.4 weeks. Of the travelers, 70% reported some health impairment. Problems reported most frequently were gastrointestinal tract diseases (43%), respiratory tract diseases (25%), and injuries (10%). Only 4% were admitted to a hospital during their trip. After their return, 19.5% consulted a physician. Comparing the group of travelers who were sick with the rest, a correlation between noncompliance with the keeping of food hygiene and illness was found (p =.008). Additional risk factors for illness were long duration (p <.001), solitary trip (p =.04), and young age (p <.001). Of the people who were advised to take antimalaria chemoprophylaxis, 55% reported regular use of these drugs. Compliance with treatment correlated with older age (p <.001), short duration of stay (p =.01), previous experience, and travel to Africa (p <.001). CONCLUSIONS: Most of the travelers to developing countries are young, travel for long periods, and live in basic conditions during their stay abroad. For these reasons travelers are at increased risk for morbidity. High risk travelers should be identified and counseled in order to increase their compliance with the medical advice and immunizations. A screening program for returning travelers should be considered.     

Fatal Israeli spotted fever in a UK traveler to South Portugal

A 63-year-old previously healthy woman developed a severe systemic infection 5 days after returning from a holiday to Southern Portugal. She subsequently died, and polymerase chain reaction of a blood sample was positive for Rickettsia conorii ssp israeliensis . The prevalence of severe forms of this illness in the Mediterranean Basin is discussed.     

African tick-bite fever: four cases among Swiss travelers returning from South Africa

BACKGROUND: African tick-bite fever (ATBF) is a recently described disease belonging to the spotted fever group. It is caused by Rickettsia africae, and cases are mainly diagnosed in travelers returning from sub-Saharan Africa. METHODS: We report four cases of ATBF among Swiss travelers returning from a 1-month trip in rural South Africa. Diagnosis was made on the basis of clinical, epidemiologic and serologic findings that we describe in detail. Serology was performed using microimmunofluorescence (MIF) assay 2 weeks, 6 weeks and 14 months after the commencement of symptoms. RESULTS: All patients developed the typical eschar and a rash; two had a local lymphadenopathy and one a lymphangitic reaction. Two patients developed transient neuropsychiatric symptoms such as headache, irritability and depressed mood. All four patients had rises in both IgM and IgG classes of anti-R. africae antibodies. After 1 year, only two patients still had measurable circulating antibodies. Cross-reactions with R. conorii were noted. Three patients were cured after a short course of doxycycline; one required 15 days of treatment. CONCLUSIONS: ATBF is a benign disease increasingly being diagnosed in travelers. After ruling out malaria, ATBF diagnosis relies upon a detailed travel history and the classical findings of influenza-like symptoms, fever, one or more necrotic eschars, and rash. Serologic tests usually help to confirm the diagnosis. Neuropsychiatric symptoms specifically associated with ATBF are reported here for the first time.     

Prospective observational study of fever in hospitalized returning travelers and migrants from tropical areas, 1997-2001

BACKGROUND: An estimated 50 million people each year from industrialized countries visit tropical areas: 3% to 11% of these travelers report a febrile illness on their return. We conducted a 5-year prospective observational study on the causes of fever in patients admitted to a university teaching hospital after returning from the tropics. METHODS: We enrolled in this study all consecutive patients admitted to the Division of Infectious Diseases of the University of Milan, Italy, between January 1997 and December 2001 presenting with fever (oral temperature > or =37.5 degrees C) and a history of travel to a tropical country in the previous 6 months. RESULTS: Seven percent (147/2,074) of all hospital admissions in the study period were due to fever in travelers and migrants returning from the tropics. Malaria accounted for 47.6 % of all admissions (70/147), followed by presumed self-limiting viral infections (12%). Pretravel screening and vaccination strategies could have prevented a considerable number of hospitalizations (e.g., hepatitis A and typhoid fever). The most useful investigations were blood examination and PCR for malaria, which gave positive results in 65% of cases in which they were performed. CONCLUSIONS: During a 5-year period, the number of patients returning from tropical areas who were admitted with fever to a university hospital in northern Italy remained stable; malaria was the most frequent diagnosis, and should be considered in any febrile patient returning from the tropics. With the exception of hepatitis A and dengue fever infections, in a real-world setting serology is of modest utility and is probably overused.     

Illnesses in travelers returning from the tropics: a prospective study of 622 patients

BACKGROUND: Although between 8 and 19% of travelers consult a doctor after returning from the tropics, the full spectrum of health complaints is unknown. METHODS: We analyzed the relative frequency of travel-associated health complaints in all travelers (immigrants returning from visiting their home countries, expatriates, business travelers, and tourists) consulting our department between November 2002 and May 2003. RESULTS: A total of 622 patients were studied (256 women, 366 men; median age 38 yr; 45.3% tourists, 33.8% immigrants, 14.1% expatriates, 6.7% business travelers). The median duration of travel was 36.9 days. The main destinations were Africa (57.6%) and Asia (26.4%). A total of 637 diseases were diagnosed, distributed as follows: skin diseases (23.4%), gastrointestinal infections (19.1%), respiratory tract infections (11.5%), malaria (8.8%), schistosomiasis (7.2%), viral hepatitis (4.1%), urinary tract infections (3.5%), sexually transmitted infections (3.5%), tuberculosis (2.7%), dengue fever (2.5%), and others (13.8%). Malaria and intestinal tract infections accounted for 21% and 23% of diagnoses in the 257 febrile travelers, respectively. Overall, 230 diagnoses (36.1%) corresponded to imported tropical diseases, the main imported diseases being malaria, schistosomiasis, amebiasis, gastrointestinal disorders caused by intestinal nematodes, and dengue fever. CONCLUSIONS: Tropical diseases are not the leading cause of consultation in travelers returning from the tropics. Immigrants are the travelers most at risk of common tropical diseases, with the noteworthy exceptions of dengue fever and invasive schistosomiasis.     

Drug abuse in travelers to southeast Asia: an on-site study

BACKGROUND: Drug abuse constitutes a major sociomedical problem throughout the world. A unique subgroup with a higher potential of drug abuse are young travelers to Southeast Asia. Less than a handful of studies have focused on this population, and even fewer have been carried out on site. Our aim was to characterize the phenomenon of drug abuse among Israelis and other nationals, and to define risk factors that would predict which travelers are prone to abusing drugs. METHODS: Data was collected through questionnaires that were distributed in Southeast Asia to 430 travelers. Medical students administered the questionnaires across India, Thailand, Nepal, Vietnam, and Laos during 2002 and 2003. RESULTS: Questionnaires from 231 Israelis and 199 other nationals (mostly from the United Kingdom, Sweden, Australia, and Germany) were analyzed. These travelers had a mean age of 25.3 years. We found that 54.3% of the travelers abused drugs during the trip. Israelis (66.2%) abused drugs more frequently than did non-Israelis (40.7%, p < .001). Males abused drugs significantly more than females did, as did secular more than religious people; however, those with an academic degree abused drugs less than others. For 23.5% of the Israelis, the trip was their first encounter with drugs. Of the entire cohort, 72% abused cannabis products, and most of them (49.6%) did it on daily basis. The use of "hard" drugs (eg, lysergic acid diethylamide) was more common among non-Israelis than among the Israelis (37% and 20%, respectively; p < .006). Much higher rates of drug abuse (70.1%) were found in India than in other Southeast Asian countries. Logistic regression identified that prior use of drugs, Israeli nationality, travel to India, cigarette smoking, and traveling alone were significant predictors of drug abuse. CONCLUSIONS: There is a disturbingly high rate of drug abuse in travelers to certain Southeast Asian countries, both among Israeli and other nationals. For many youngsters, this is their first encounter with drugs, and many plan to continue abusing drugs upon their repatriation. Travelers to Southeast Asia should be a major target group for primary, preventive, antidrug campaigns worldwide.     

Adverse drug reaction-related hospitalisations: a nationwide study in The Netherlands.

BACKGROUND: The incidence of adverse drug reaction (ADR)-related hospitalisations has usually been assessed within hospitals. Because of the variability in results and methodology, it is difficult to extrapolate these results to a national level. OBJECTIVES: To evaluate the incidence and characteristics of ADR-related hospitalisations in The Netherlands in 2001. METHODS: We conducted a nationwide study of all hospital admissions in 2001. Data were retrieved from a nationwide computer database for hospital discharge records. All acute, non-planned admissions to all Dutch academic and general hospitals in 2001 were included in the study (n = 668 714). From these admissions we selected all hospitalisations that were coded as drug-related, but intended forms of overdose, errors in administration and therapeutic failures were excluded. Hence, we extracted all ADR-related hospitalisations. We compared age, sex and the risk of a fatal outcome between patients admitted with ADRs and patients admitted for other reasons, as well as the most frequent main diagnoses in ADR-related hospitalisations and which drugs most frequently caused the ADRs. In addition, we evaluated to what extent these ADRs were reported to the Netherlands Pharmacovigilance Centre Lareb for spontaneous ADR reporting. RESULTS: In 2001, 12 249 hospitalisations were coded as ADR related. This was 1.83% of all acute hospital admissions in The Netherlands (95% CI 1.80, 1.86). The proportion increased with age from 0.8% (95% CI 0.75, 0.85) in the <18 years group to 3.2% in the >/=80 years group (95% CI 3.08, 3.32). The most frequent ADR-related diagnoses of hospitalisations were bleeding (n = 1048), non-specified 'unintended effect of drug' (n = 438), hypoglycaemia (n = 375) and fever (n = 347). The drugs most commonly associated with ADR-related hospitalisations were anticoagulants (n = 2185), cytostatics and immunosuppressives (n = 1809) and diuretics (n = 979). Six percent of the ADR-related hospitalisations had a fatal outcome (n = 734). Older age and female gender were associated with ADR-related hospitalisations. Only approximately 1% of the coded ADRs causing hospitalisation were reported to our national centre for spontaneous ADR reporting. CONCLUSION: The proportion of ADR-related hospitalisations is substantial, especially considering the fact that not all ADRs may be recognised or mentioned in discharge letters. Under-reporting of ADRs that result in hospital admission to our national centre for spontaneous ADR reporting was considerable.