Lack of Neisseria meningitidis among pilgrims during the 2017, 2018 and 2019 Grand Magal of Touba, Senegal

Travel-related respiratory symptoms and infections in travellers (2000-22): a systematic review and meta-analysis

BACKGROUND

Respiratory tract infections (RTIs) are common in travellers due to the year-round or seasonal presence of respiratory pathogen and exposure to crowded environments during the itinerary. No study has systematically examined the burden of RTI infections among travellers. The aim of this systematic review and meta-analysis is to evaluate the prevalence of RTIs and symptoms suggestive of RTIs among travellers according to risk groups and/or geographic region, and to describe the spectrum of RTIs.

METHODS

The systematic review and meta-analysis was registered in PROSPERO (CRD42022311261). We searched Medline, Embase, Scopus, Cochrane Central, Web of Science, Science Direct and preprint servers MedRxiv, BioRxiv, SSRN and IEEE Xplore on 1 February 2022. Studies reporting RTIs or symptoms suggestive of RTIs in international travellers after 1 January 2000 were eligible. Data appraisal and extraction were performed by two authors, and proportional meta-analyses were used to obtain estimates of the prevalence of respiratory symptoms and RTIs in travellers and predefined risk groups.

FINDINGS

A total of 429 articles on travellers' illness were included. Included studies reported 86 841 symptoms suggestive of RTIs and 807 632 confirmed RTIs. Seventy-eight percent of reported respiratory symptoms and 60% of RTIs with available location data were acquired at mass gatherings events. Cough was the most common symptom suggestive of respiratory infections, and the upper respiratory tract was the most common site for RTIs in travellers. The prevalence of RTIs and respiratory symptoms suggestive of RTIs were 10% [8%; 14%] and 37% [27%; 48%], respectively, among travellers. Reporting of RTIs in travellers denoted by publication output was found to correlate with global waves of new respiratory infections.

INTERPRETATION

This study demonstrates a high burden of RTIs among travellers and indicates that travellers' RTIs reflect respiratory infection outbreaks. These findings have important implications for understanding and managing RTIs among travellers.

Epidemiological Investigations of Infectious Diseases among Mobile Populations at the University Hospital Institute Mediterranean Infection in Marseille, France

We review the most recent work conducted by our group on the circulation of infectious agents in mobile populations, including pilgrims participating in the Hajj (Mecca, Saudi Arabia) and the Grand Magal of Touba (Senegal) pilgrimages, homeless people, and medical students participating in an elective abroad. Using a similar epidemiological study design with standardized questionnaires and molecular assays allows comparison of different populations of travelers. The main infectious pathogens and antibiotic resistance genes linked to travel were identified in certain specific populations of travelers, as well as in a group of homeless migrant people in Marseille. The role of several risk factors has also been demonstrated, allowing identifying individuals at increased risk of disease or pathogen carriage on which to base targeted preventive measures. Such results, together with those obtained through international surveillance networks allow better description of the epidemiology of travel-associated infectious diseases.

Respiratory infections among pilgrims at the Grand Magal of Touba: A comparative cohort controlled survey

BACKGROUND

The Grand Magal of Touba (GMT) is a large event gathering around 4-5 million participants every year. A pilot study conducted in 2017 among GMT pilgrims showed that 41.8% of participants reported respiratory symptoms, mostly due to rhinovirus (13.0%), coronaviruses (16.0%) and adenovirus (4.6%).

METHODS

A PCR-based prospective cohort study was conducted among GMT pilgrims and controls (who did not participate to the event) in two rural villages in South Senegal, in 2019.

RESULTS

93 pilgrims and 84 controls were included in the study. There were no significant differences between pilgrims and controls regarding demographic characteristics and chronic conditions. 60.2% of pilgrims reported respiratory symptoms during their stay in Touba, or soon after their return. By contrast, only 8.3% of controls reported respiratory symptoms after the GMT. The acquisition of rhinovirus, coronaviruses, Streptococcus pneumoniae and Moraxella catarrhalis was 22.6%, 6.5%, 17.2% and 6.8% respectively in pilgrims and was significantly higher than in controls (3.6%, 0%, 4.8% and 1.2% respectively). Respiratory symptoms post-GMT were five times more frequent in S. pneumoniae carriers (aOR = 5.18, 95%CI = [1.98-13.57]).

CONCLUSION

This study demonstrates that individuals who participated in the GMT were at higher risk of suffering from respiratory symptoms and that this was linked to the acquisition of S. pneumoniae.