Incidence and predictors of severe altitude illness symptoms in Mt. Kilimanjaro hikers: a prospective cohort study

BACKGROUND

Each year several Mt. Kilimanjaro hikers die due to altitude illness (AI) although urgent descent is technically easily possible. The objectives of this study were to determine the incidence and predictors of severe altitude illness (SAI) symptoms and of summit success in Mt. Kilimanjaro hikers, and the measures taken when AI symptoms develop.

METHODS

A prospective observational cohort study in Mt. Kilimanjaro hikers was conducted from December 2019 until March 2020. Participants were asked to complete a questionnaire at the entrance gate and one at the descend gate. A multivariate logistic regression was performed to study the relations between the variables.

RESULTS

A total of 1237 recreational hikers and 266 porters or guides were included. The incidence of severe symptoms was 8.6% in recreational hikers and 1.5% in porters and guides. One percent (1.1%) of hikers was hospitalized due to SAI. A history of SAI, young age, summit failure and lack of clear advice predicted the development of severe symptoms. Uhuru peak was reached by 87.9% of the hikers. Absence of severe symptoms, acetazolamide prophylaxis, climbing higher in daytime, young age and climbing in more days predicted summit success. The majority climbed further despite the presence of mild or severe symptoms. The only measure taken in case of mild symptoms that was associated with a lower incidence of severe symptoms was not climbing further.

CONCLUSION

The incidence of SAI symptoms in Mt. Kilimanjaro hikers was observed to be high. However, how hikers reacted during symptoms was not appropriate. Therefore, travel health counsellors should emphasize even more that hikers do not ascend higher until mild symptoms have resolved and that it is vital to descend immediately when severe symptoms develop. In addition, they can be informed on the measures, which improved summit success.

Rabies risk behaviour in a cohort of Dutch travel clinic visitors: A retrospective analysis

BACKGROUND

Travellers to rabies endemic countries should be counselled on rabies risk and, in case of high-risk, pre-exposure vaccination is advised. However, it is not clear which travellers exactly are at high risk. In this study we determined the incidence of possible rabies exposure in travel clinic visitors and compliance with pre-travel advice.

METHODS

Travellers to rabies endemic countries who visited a Dutch travel clinic between September 2017 and May 2018, were invited to participate.

RESULTS

Of 980 travellers, one percent was injured by a potentially rabid animal. Compliance with advice was low as 59% reported proximity to a potentially rabid animal and only half of those exposed sought medical advice. The most important predictors of proximity to a potentially rabid animal were young age, long travel duration, visiting a monkey forest and hiking for more than one day. Travel for business was associated with lower risk.

CONCLUSION

Despite pre-travel advice, rabies risk behaviour was high. Therefore, we would recommend to keep the threshold for pre-travel vaccination low. Pending more data on rabies exposure risk, the identified predictors of proximity to potentially rabid animals could be used to tailor indications for pre-travel rabies vaccination.

Time of administration of rabies immunoglobulins and adequacy of antibody response upon post-exposure prophylaxis: a descriptive retrospective study in Belgium

Background: Data on rabies post-exposure prophylaxis (PEP) and the use of human rabies immunoglobulins (HRIG) in Belgium are scarce. The main objective of this study was to evaluate the timely administration of HRIG after rabies exposure. The secondary objective was to evaluate the adequate antibody response following PEP.Methods: We reviewed all medical records from July 2017 to June 2018 of patients seeking care at, or referred to, the Institute of Tropical Medicine and the University Hospital, Antwerp for the administration of human rabies immunoglobulins following potential rabies exposure abroad or in Belgium.A timely response was defined as starting HRIG with a delay of ≤48 h and rabies vaccination in the first 7 days after exposure.Adequate antibody response was defined as a titer of >5.0 IU/mL in case of bat-related exposure and >3.0 IU/mL in case of exposure to other animals. Titers were measured 10 days after the last PEP vaccine dose, using the rapid fluorescent focus inhibition test (RFFIT).Results: Of the 92 cases treated with HRIG, 75 were evaluated.The majority of injuries were acquired in Asia (n = 26,34%) and in Western Europe (n = 18, 24%), of which 17 in Belgium. The five most frequently recorded countries overseas were Indonesia (n = 13), Thailand (n = 7), Morocco (n = 4), Peru (n = 3) and Costa Rica (n = 3). Administration of immunoglobulins was related to injuries by dogs (36%), monkeys (25%) or bats (22%).A timely response was observed in 16 (21,33%) and in 55 (73,33%) of subjects receiving HRIG (≤48 h) or rabies vaccine (<7days) respectively. The mean time between exposure and the first administered dose of rabies vaccine and HRIG was 7.7 and 8.7 days, respectively. The mean delay for HRIG administration was 9.6 days and 6 days for abroad and inland risks, respectively.In 15 of 16 (94%) bat-related cases the antibody titer after full PEP was >5.0 IU/ml. In 38 of 47 (81%) cases related to other animals the RFFIT titer was >3.0 IU/ml. All low-responders received additional rabies injections.Conclusion: This study showed a substantial time delay between the animal-related risk and the administration of HRIG, in particular when the injury occurred abroad. More targeted communication about the risks of rabies and preventable measures may reduce this delay.Furthermore, the antibody response was inadequate in some cases following full PEP administration according to the Belgian recommendation.

Simplified rabies pre-exposure prophylaxis in last-minute travellers

Less can be more: simplified two-visit rabies pre-exposure prophylaxis once in a lifetime will certainly increase compliance in last-minute travellers and ease the post-exposure procedures after animal risks in endemic countries. Different arguments are being put forward to shorten this vaccination scheme even further into an effective one-day scheme.

A risk scoring system to identify travellers who qualify for pre-exposure rabies vaccination

We want to introduce a free online scoring system to identify high risk travellers who qualify for pre-travel rabies vaccination. The system uses evidence based risk predictors and the probable availability of HRIG at the destination.

Increase in imported malaria in the Netherlands in asylum seekers and VFR travellers

Background

Malaria is a notifiable disease in the Netherlands, a non-endemic country. Imported malaria infections occur regularly among travellers, migrants and visitors. Surveillance data were analysed from 2008 to 2015. Trends in amounts of notifications among risk groups were analysed using Poisson regression. For asylum seekers, yearly incidence was calculated per region of origin, using national asylum request statistics as denominator data. For tourists, denominator data were used from travel statistics to estimate incidence per travel region up to 2012.

Results

A modest increase in overall imported malaria notifications occurred in 2008–2015 (from 222 in 2008 to 344 in 2015). Notably, in 2014 and 2015 sharp increases were seen in malaria among travellers visiting friends and relatives (VFR), and in asylum seekers. Of all Plasmodium falciparum infections, most (1254/1337; 93.8%) were imported from Africa; 1037/1337 (77.6%) were imported from Central and West Africa. Malaria in VFR was mostly caused by P. falciparum infection after visiting Ghana (22%) or Nigeria (19%). Malaria in asylum seekers was mostly caused by Plasmodium vivax infection from the Horn of Africa. The large number of notifications in asylum seekers resulted from both an increase in number of asylum seekers and a striking increase of malaria incidence in this group. Incidence of malaria in asylum seekers from the Horn of Africa ranged between 0.02 and 0.3% in 2008–2013, but rose to 1.6% in 2014 and 1.3% in 2015. In 2008–2012, incidence in tourists visiting Central and West Africa dropped markedly.

Conclusions

Imported malaria is on the rise again in the Netherlands, most notably since 2013. This is mostly due to immigration of asylum seekers from the Horn of Africa. The predominance of P. vivax infection among asylum seekers warrants vigilance in health workers when a migrant presents with fever, as relapses of this type of malaria can occur long after arrival in the Netherlands.

Electronic supplementary material

The online version of this article (doi:10.1186/s12936-017-1711-5) contains supplementary material, which is available to authorized users.

Do travel clinic visitors read information on sexual risk abroad in travel health brochures?

BACKGROUND

A substantial proportion of travel clinic visitors have sexual encounters while abroad. Hence, guidelines on travel health recommend discussing sexual risk in a pre-travel consultation. However, previous studies showed that it often is not discussed. Although travel clinic visitors usually do receive written information on sexual risk abroad, few data are available on whether this information is read. Therefore, this prospective cohort study in travel clinic visitors was performed.

METHODS

Travel clinic visitors were invited to complete a questionnaire after return from their journey.

RESULTS

A total of 130 travellers (55%) responded. Half of them recorded they read the information on sexual risk. Male gender (OR 9.94 95% CI 3.12 - 31.63) and 'travelling with others' (OR 2.7 95% CI 1.29 - 5.78) were significant independent predictors of reading the information on sexual risk. High risk travellers, i.e. those travelling without a steady partner, were less likely to have read it. Although websites and apps were mentioned as better methods of providing information, none of the participants visited the websites on sexual behaviour and sexually transmitted infections recommended in the travel health brochure.

CONCLUSION

Only half of travel clinic visitors read information on sexual risk in the health brochure received in the clinic and none of them visited the related websites mentioned in the brochure. Further research to identify the most effective way to inform travellers about sexual risk is needed.

Serious altitude illness in travelers who visited a pre-travel clinic

BACKGROUND

Few data are available on the incidence and predictors of serious altitude illness in travelers who visit pre-travel clinics. Travel health consultants advise on measures to be taken in case of serious altitude illness but it is not clear if travelers adhere to these recommendations.

METHODS

Visitors to six travel clinics who planned to travel to an altitude of ≥3,000 m were asked to complete a diary from the first day at 2,000 m until 3 days after reaching the maximum sleeping altitude. Serious altitude illness was defined as having symptoms of serious acute mountain sickness (AMS score ≥ 6) and/or cerebral edema and/or pulmonary edema.

RESULTS

The incidence of serious altitude illness in the 401 included participants of whom 90% reached ≥4,000 m, was 35%; 23% had symptoms of serious AMS, 25% symptoms of cerebral edema, and 13% symptoms of pulmonary edema. Independent predictors were young age, the occurrence of dark urine, travel in South America or Africa, and lack of acclimatization between 1,000 and 2,500 m. Acetazolamide was brought along by 77% of the responders of whom 41% took at least one dose. Of those with serious altitude illness, 57% had taken at least one dose of acetazolamide, 20% descended below 2,500 m on the same day or the next, and 11% consulted a physician.

CONCLUSIONS

Serious altitude illness was a very frequent problem in travelers who visited pre-travel clinics. Young age, dark urine, travel in South America or Africa, and lack of acclimatization nights at moderate altitude were independent predictors. Furthermore, we found that seriously ill travelers seldom followed the advice to descend and to visit a physician.

The effect of pre-travel advice on sexual risk behavior abroad: a systematic review

BACKGROUND

Travelers often have casual sex abroad and the risk of acquiring a sexually transmitted infection (STI) associated with casual travel sex is considered to be threefold higher compared to the risk of casual sex in the home country. Consequently, international guidelines recommend including STI advice in the pre-travel consultation. We performed a systematic review on the effect of a pre-travel STI intervention on sexual risk behavior abroad.

METHODS

In September 2012, a systematic analysis and meta-analysis of peer reviewed literature were performed on the relation between pre-travel STI advice for travelers and sexual risk behavior abroad. Primary outcome measure consisted of the number of travelers with a new sexual partner abroad; secondary outcome measure entailed the proportion of consistent condom use.

RESULTS

Six studies were identified for inclusion in the review, of which three clinical trials on the effect of a motivational intervention compared to standard pre-travel STI advice qualified for the meta-analysis. Two of these trials were performed in US marines deployed abroad and one in visitors of a travel clinic. The extensive motivational training program of the marines led to a reduction in sexual risk behavior, while the brief motivational intervention in the travel clinic was not superior to standard advice. The meta-analysis established no overall effect on risk behavior abroad. No clinical trials on the effect of a standard pre-travel STI discussion were found, but a cohort study reported that no relation was found between the recall of a nonstructured pre-travel STI discussion and sexual risk behavior, while the recall of reading the STI information appeared to be related to more consistent condom use.

CONCLUSIONS

Motivational pre-travel STI intervention was not found to be superior to standard STI advice, while no clinical trials on the effect of standard pre-travel STI advice were found.

Acute mountain sickness in travelers who consulted a pre-travel clinic

BACKGROUND

The main objective of this study was to investigate the incidence and predictors of acute mountain sickness (AMS) in travelers who consulted a pre-travel clinic and the compliance with advices concerning this condition.

METHODS

A post-travel questionnaire was sent to clients of five travel clinics who planned to climb above 2,000 m.

RESULTS

The response was 77% and the data of all 744 respondents who stayed above 2,500 m were used for the analysis. Eighty-seven percent (646) read and understood the written advices on AMS. The incidence of AMS was 25% (184), and the predictors were previous AMS [odds ratio (OR) 2.2], female sex (OR 1.6), age (OR 0.98 per year), maximum sleeping altitude (OR 1.2 per 500 m), and the number of nights between 1,500 and 2,500 m (OR 0.9 per night). Eighty-seven percent of respondents understood the written advices about AMS but 21% did not read or understand the use of acetazolamide. Forty percent spent less than two nights between 1,500 and 2,500 m and 43% climbed more than 500 m/d once above 2,500 m. Acetazolamide was brought along by 541 respondents (72%) and 116 (16%) took it preventively. Of those with AMS 62 (34%) took acetazolamide treatment and 87 (47%) climbed higher despite AMS symptoms. The average preventive dose of acetazolamide was 250 mg/d, while the average curative dose was 375 mg/d. We found no relation between acetazolamide prevention and AMS (p = 0.540).

CONCLUSIONS

The incidence of AMS in travelers who stayed above 2,500 m was 25%. Predictors were previous AMS, female sex, age, maximum overnight altitude, and the number of nights between 1,500 and 2,500 m. Only half of these travelers followed the preventive and curative advices and 21% did not read or understand the use of acetazolamide. We found no preventive effect of a low dose of acetazolamide in this retrospective observational study.

Sexual risk behavior of travelers who consulted a pretravel clinic

OBJECTIVE

The objective of this study was to determine to which degree travelers who received pretravel advice at a travel clinic have protected or unprotected sexual contact with a new partner and what factors influence this behavior.

METHOD

An anonymous questionnaire was sent to travelers who came to a pretravel clinic between June 1 and August 31, 2005. Risk factors for casual travel sex and predictors of protected sex were studied in a multivariate model.

RESULTS

A total of 1,907 travelers were included (response rate 55%) in the study. Only 4.7% of the respondents had sexual contact with a new partner, and 63.1% of these new partners were from the country of destination. Of those who had casual travel sex, 52.4% did not expect this (women 75%), 30.9% did not always use condoms, and 41% were not protected against hepatitis B. Independent risk factors for casual travel sex were traveling without steady partner (OR 14.4), expecting casual travel sex (OR 9.2), having casual sexual contacts in the home country (OR 2.4), non-tourist journeys (OR 2.2), being male (OR 2.1), the fact that the information on sexually transmitted infections (STI) had been read (OR 2.0), and traveling to South and Central America (OR 2.0). Taking condoms along (OR 5.4) and reading the information on STI (OR 3.3) were identified as independent predictors of protected sex.

CONCLUSIONS

Travelers have substantial sexual risk behavior. Casual sex is usually not expected, and the most important predictor is traveling without a steady partner. We would advice every client of a travel clinic who will travel without a steady partner to read the STI information, to take condoms along, and to be vaccinated against hepatitis B.