Burden of typhoid fever and cholera: similarities and differences. Prevention strategies for European travelers to endemic/epidemic areas

Abstract

The burden of diarrheal diseases is very high, accounting for 1.7 to 5 billion cases per year worldwide. Typhoid fever (TF) and cholera are potentially life-threatening infectious diseases, and are mainly transmitted through the consumption of food, drink or water that have been contaminated by the feces or urine of subjects excreting the pathogen. TF is mainly caused by Salmonella typhi, whereas cholera is caused by intestinal infection by the toxin-producing bacterium Vibrio cholerae. These diseases typically affect low- and middle-income countries where housing is overcrowded and water and sanitation are poor, or where conflicts or natural disasters have led to the collapse of the water, sanitation and healthcare systems. Mortality is higher in children under 5 years of age. Regarding their geographical distribution, TF has a high incidence in sub-Saharan Africa, India and south-east Asia, while cholera has a high incidence in a few African countries, particularly in the Horn of Africa and the Arabian Peninsula. In the fight against these diseases, preventive measures are fundamental. With modern air travel, transmissible diseases can spread across continents and oceans in a few days, constituting a threat to global public health. Nowadays, people travel for many reasons, such as tourism and business. Several surveys have shown that a high proportion of travelers lack adequate information on safety issues, such as timely vaccination and prophylactic medications. The main objective of this overview is to provide information to help European travelers to stay healthy while abroad, and thus also to reduce the potential importation of these diseases and their consequent implications for public health and society. The preventive measures to be implemented in the case of travel to countries where these diseases are still endemic are well known: the adoption of safe practices and vaccinations. It is important to stress that an effective preventive strategy should be based both on vaccinations and on hygiene travel guidelines. Furthermore, the emergence of multidrug-resistant strains is becoming a serious problem in the clinical treatment of these diseases. For this reason, vaccination is the main solution.

Keywords: Cholera; Cholera vaccines; International travel; Salmonella Typhi; Travel medicine; Typhoid fever vaccines.

Fig. 1.

Typhoid incidence in low- and middle-income countries (risk-adjusted and corrected for blood culture sensitivity), adapted from Mogasale et al. [19]. Colors indicate different incidence values, with darker shades corresponding to higher incidence.

Fig. 2.

Incidence in the Global Burden of Disease regions and sub-regions made up of low- and middle-income countries. The incidence is per 100,000 person-years. Adapted from Antillón et al. [20].

Fig. 3.

Countries reporting cholera cases in 2017 (Adapted from WHO, 2018) [67]. The colors indicate different values of incidence; a darker shade corresponds to a higher incidence.