Risk Factors for Typhoid Fever in Travelers

Low and declining attack rates of imported typhoid fever in the Netherlands 1997-2014, in spite of a restricted vaccination policy

Background

Typhoid fever mainly occurs in (sub) tropical regions where sanitary conditions remain poor. In other regions it occurs mainly among returning travelers or their direct contacts. The aim of this study was to evaluate the current Dutch guidelines for typhoid vaccination.

Method

Crude annual attack rates (AR) per 100,000 Dutch travelers were calculated during the period 1997 to 2014 by dividing the number of typhoid fever cases by the estimated total number of travelers to a specific country or region. Regions of exposure and possible risk factors were evaluated.

Results

During the study period 607 cases of typhoid fever were reported. Most cases were imported from Asia (60%). Almost half of the cases were ethnically related to typhoid risk regions and 37% were cases visiting friends and relatives. The overall ARs for travelers to all regions declined significantly. Countries with the highest ARs were India (29 per 100,000), Indonesia (8 per 100,000), and Morocco (10 per 100,000). There was a significant decline in ARs among travelers to popular travel destinations such as Morocco, Turkey, and Indonesia. ARs among travelers to intermediate-risk areas according to the Dutch guidelines such as Latin America or Sub-Saharan Africa remained very low, despite the restricted vaccination policy for these areas compared to many other guidelines.

Conclusion

The overall AR of typhoid fever among travelers returning to the Netherlands is very low and has declined in the past 20 years. The Dutch vaccination policy not to vaccinate short-term travelers to Latin-America, Sub-Saharan Africa, Thailand and Malaysia seems to be justified, because the ARs for these destinations remain very low. These results suggest that further restriction of the Dutch vaccination policy is justified.

Enteric fever in Barcelona: Changing patterns of importation and antibiotic resistance

BACKGROUND

Enteric fever's incidence is decreasing among residents of high-income countries, although it's rising in travelers coming from low-resource endemic settings. The study's aim is to describe epidemiological, clinical and laboratory features of patients with enteric fever.

METHODS

Retrospective descriptive study of enteric fever cases diagnosed at a Tropical Medicine Unit in Barcelona, 1993-2012.

RESULTS

Out of 40 patients, 31(77,5%) were returning travelers, and 70% of them had been in Southern Asia. In the rest of patients without an antecedent of a recent travel, the infection occurred mainly before year 2000. The more frequently reported symptoms were fever and diarrhea, lacking significant differences between S. typhi and S. paratyphi infections. Quinolones were used as empiric treatment in 47.2% of patients, 36.1% received 3rd generation cephalosporins, 2.78% azithromycin and 13.89% other combinations. Resistance to quinolones in the S. paratyphi group (66.7%) was significantly higher compared with the S. typhi group (20%) (p:0.02). 22.5% of patients had treatment failure and 23.6% patients presented complications, none of them had been previously vaccinated.

CONCLUSIONS

The diagnosis of enteric fever was more frequent among travelers coming from Southern-East Asia. Quinolone resistance is widely spread, particularly in S. paratyphi serotypes and should not be considered as first choice treatment anymore.

Enteric fever in a UK regional infectious diseases unit: a 10 year retrospective review

INTRODUCTION

Enteric fever is an increasingly common diagnosis in returning travellers in the UK.

METHODS

We performed a retrospective descriptive study of culture-confirmed cases of enteric fever admitted to University Hospitals Leicester, UK between January 1999 and April 2009.

RESULTS

100 cases of enteric fever were identified in adults (n = 76) and children (n = 24). The median age of adult subjects was 38 (range 18-71) and 55% were male. Of the 61 adult cases with notes available, 60 (98.3%) were of Asian ethnicity and 56 (92%) had a recent travel history, principally to the Indian Subcontinent. Symptoms included fever (100%), headache (62%), diarrhoea (59%) and abdominal pain (44%). Common examination findings included pyrexia and mild generalized abdominal tenderness. Mild hyponatraemia, transaminitis and a normal white cell count were commonly identified. Reduced ciprofloxacin sensitivity was common and increased over the study period. Median fever clearance time was 6 days, and treatment failure occurred in 20% of cases. Relapse occurred in 2 patients. Complications were unusual, and one patient died.

DISCUSSION

Patients with enteric fever presented with a non-specific febrile illness within one month after returning from travel, and most had an uncomplicated clinical course. Increasing ciprofloxacin insensitivity was the likely explanation for a high treatment failure rate and this agent can no longer recommended as empirical treatment.

Tick-borne Encephalitis – a European Health Challenge Conference report of the 8th meeting of the International Scientific Working Group on Tick-borne Encephalitis (ISW TBE)

The annual 2006 meeting of the International Scientific Working Group on Tick-borne Encephalitis (ISW TBE) raised the topic "Tick-borne Encephalitis--a European Health Challenge". TBE incidence has more or less increased in all European countries with a TBE risk in the last years (excepting Austria). Additionally, TBE has become an international public health problem because of increasing mobility of people travelling to risk areas. TBE vaccination should be recommended when people travel to endemic regions and come into contact with nature, regardless of the duration of the stay. As no clear recommendations for travellers exist, it will be one of the major future challenges of the ISW TBE to increase problem awareness outside endemic regions and create general recommendations, which are valid for at least all European countries.

Typhoid and paratyphoid fever in travellers

Enteric fever--a more inclusive term for typhoid fever and paratyphoid fever--is a systemic infection caused by Salmonella enterica, including S enterica serotype Typhi (S typhi) and serotype Paratyphi (S paratyphi). In developed countries there have been two major changes in the pattern of the disease: a marked decline in its incidence and its characterisation as a predominantly travel-associated disease. The risk to travellers appears to vary by geographic region visited, with travel to the Indian subcontinent accounting for the greatest travel risk. Although the most common cause of enteric fever is S typhi, the incidence of disease caused by S paratyphi among travellers may be more important, since the available vaccines only protect against S typhi. Descriptions of the clinical presentation in travellers are scarce but severe complications and death are rare, probably due to rapid access to readily available medical care. Drug resistance reflects the situation in endemic countries, and shows a steady increase in multidrug-resistance patterns. Currently, the recommendation for first-line therapy is ceftriaxone and, where isolates have been found to be quinolone sensitive, fluoroquinolones can still be given. Preventive measures are educating travellers about hygiene precautions and vaccination. With an increase in multidrug-resistant strains, a more effective vaccine for S typhi and S paratyphi is urgently needed.

Clinical and bacteriological profiles of patients with typhoid fever treated during 1975-1998 in the Tokyo Metropolitan Komagome Hospital

Patients with typhoid fever presenting to the Tokyo Metropolitan Komagome Hospital during the period 1975-1998 were retrospectively investigated. All cases were diagnosed by a positive culture for Salmonella typhi in either of their clinical specimens. Of the total number of 130 patients, 57% contracted the disease abroad; this population increased in later years as the total numbers of cases decreased. The period from disease onset to diagnosis averaged 14 days with 20% of the cases requiring over three weeks to establish a diagnosis. As for symptomatology relative bradycardia was seen in less than half of the cases, and rose spots or splenomegaly in less than one third. A positive blood culture was the most frequent test establishing the diagnosis followed by a positive stool culture. Intestinal bleeding was recognized in as many as 35 cases (27%) and even intestinal perforation occurred in two cases (1.5%). Chloramphenicol was most commonly employed during the early study period, however, during the late period it was replaced by fluoroquinolones. The clinical cure rate was 98% with regimens that include fluoroquinolones/quinolone; however it was 87% with the other antimicrobial regimens. Bacteriological relapse occurred in 25% of the non-fluoroquinolone group while only in 2.0% in the fluoroquinolone/quinolone group. Four strains of Salmonella typhi that were multi-resistant to chloramphenicol, ampicillin and cotrimoxazole were isolated in travelers from Asia. Early diagnosis by appropriate bacteriological examination regardless of classical symptomatology should be stressed and the use of fluoroquinolones is warranted in the treatment of typhoid fever.

Concomitant vaccination against hepatitis A and typhoid fever

BACKGROUND

The purpose of this study was to evaluate the reactogenicity and immunogenicity of a hepatitis A vaccine (Havrix-1440TM) when administered simultaneously with a Vi polysaccharide typhoid vaccine.

METHODS

Two open, randomized studies were conducted using 2 and 4 treatment groups respectively, at the Clinique Notre-Dame de Grâce, Belgium (Study 1) and University Hospital of Hradec Kralové, Czech Republic (Study 2).

SUBJECTS

Healthy adults aged 18-50 years were administered either both vaccines concomitantly in separate arms or a single injection of the two vaccines mixed extemporaneously (Study 1), or one injection of each vaccine alone, or the combined vaccine, or both vaccines concomitantly in separate arms (Study 2). The study measured solicited and unsolicited signs and symptoms until 28 days post-vaccination. Anti-hepatitis A and anti-Vi titers were determined in pre- and post-vaccination sera.

RESULTS

The vast majority of local and general symptoms were mild to moderate and all resolved without sequelae. No serious adverse events were reported in either study. In study 1, geometric mean antibody titers (GMTs) were similar after extemporaneous syringe mixing of both vaccines (anti-Vi = 1159 EL.U/mL; anti-HAV = 302 EL.U/mL) and after concomitant vaccination (anti-Vi = 1331 EL.U/mL; anti-HAV = 367 EL. U/mL). In study 2, GMTs following vaccination with either vaccine alone, both vaccines administered concomitantly or as a combined vaccine (anti-Vi: 1307, 1247 and 942 EL.U/mL, respectively; anti-HAV: 462, 517 and 432 EL.U/mL, respectively) were not significantly different (p = .45 for anti-HAV, p = .18 for anti-Vi). Seroconversion rates were > 94.4% in all cases.

CONCLUSIONS

The inactivated hepatitis A and Vi polysaccharide typhoid vaccines are safe and well tolerated when administered simultaneously (mixed or concomitant) and as a combined vaccine. Subjects seroconverted to both antigens to the same extent as the monovalent vaccines and there was no cross-interference in the immune profiles of the vaccines.