Exposure to enteroviruses and hepatitis A virus among divers in environmental waters in France, first biological and serological survey of a controlled cohort

Illnesses Associated with Freshwater Recreation During International Travel

PURPOSE OF REVIEW

International travel, adventure travel, and eco-tourism are increasing over the past few decades. This review aims to summarize the spectrum of infections associated with recreational freshwater activities and international travel.

RECENT FINDINGS

Recreational water activities can be associated with a wide range of infections. Acute febrile illnesses due to leptospirosis and schistosomiasis are not uncommon in travelers following extensive freshwater exposure. Aeromonas and other water-associated pathogens are important to consider in a traveler presenting with a skin and soft tissue infection. Recreational water activities are often associated with diarrheal illnesses, especially in children, and the range of enteric pathogens includes bacterial pathogens such as Escherichia coli O157:H7 and Shigella species and the protozoan parasites Cryptosporidium and Giardia duodenalis. Infections due to free-living amebas though rare can lead to fulminant central nervous system infections. A diverse range of infections may be associated with freshwater exposure, and it is important that these entities are considered in a returning traveler presenting with an acute illness.

Hepatitis A seroprevalence in public school children in Campos dos Goytacazes, Rio de Janeiro State, Brazil, prior to the introduction of the hepatitis A universal childhood vaccination

This cross-sectional study was carried out between August 2011 and July 2012 in the city of Campos dos Goytacazes in Rio de Janeiro State, Brazil. Dried blood spot samples were collected on filter paper from 919 individuals between the ages of 1 and 19 and were tested for antibodies against the hepatitis A virus (anti-HAV). The total prevalence was 20.7%, while 94.7% of children under the age of 5 were found to be susceptible to HAV infection. The prevalence of anti-HAV increased with age, reaching 33.3% among individuals aged between 15 and 19, thereby indicating that this municipality has a low level of endemicity for hepatitis A. Age, non-white skin color, accustomed to swimming in the river and more than five people living at home were the factors that were associated with an increase in the chance of a positive anti-HAV result. Mother's education level (secondary or tertiary) was considered a protective factor for HAV infection. The data obtained showed that a large proportion of the children from Campos dos Goytacazes were at risk of HAV infection, which should be minimized with the introduction of the vaccination program against hepatitis A that was launched in the municipality in 2011.

A survey of diving behaviour and accidental water ingestion among Dutch occupational and sport divers to assess the risk of infection with waterborne pathogenic microorganisms

Divers may run a higher risk of infection with waterborne pathogens than bathers because of more frequent and intense contact with water that may not comply with microbiologic water quality standards for bathing water. In this study we aimed to estimate the volume of water swallowed during diving as a key factor for infection risk assessment associated with diving. Using questionnaires, occupational and sport divers in the Netherlands were asked about number of dives, volume of swallowed water, and health complaints (nausea, vomiting, diarrhea, and ear, skin, eye, and respiratory complaints). Occupational divers, on average, swallowed 9.8 mL marine water and 5.7 mL fresh surface water per dive. Sport divers swallowed, on average, 9.0 mL marine water; 13 mL fresh recreational water; 3.2 mL river, canal, or city canal water; and 20 mL water in circulation pools. Divers swallowed less water when wearing a full face mask instead of an ordinary diving mask and even less when wearing a diving helmet. A full face mask or a diving helmet is recommended when diving in fecally contaminated water. From the volumes of swallowed water and concentrations of pathogens in fecally contaminated water, we estimated the infection risks per dive and per year to be as high as a few to up to tens of percents. This may explain why only 20% of the divers reported having none of the inquired health complaints within a period of 1 year. It is highly recommended that divers be informed about fecal contamination of the diving water.

Enteroviruses and bacteriophages in bathing waters

A new procedure for detecting and counting enteroviruses based on the VIRADEN method applied to 10 liters of seawater was examined. It improved the efficiency of detection by taking into account both the number of positive isolations and numbers found with traditional methods. It was then used to quantify viruses in bathing waters. A number of bacterial indicators and bacteriophages were also tested. Cultivable enteroviruses were detected in 55% of the samples, most of which complied with bacteriological criteria. In contrast, viral genomes were only detected in 20% of the samples by reverse transcription-PCR. Somatic coliphages outnumbered all other indicators. F-specific RNA phages were detected in only 15% of the samples, whereas phages infecting Bacteroides thetaiotaomicron were detected in 70% of samples. A numerical relationship between the numbers of enteroviruses and the numbers of enterococci and somatic coliphages was observed. In situ inactivation experiments showed that viruses persisted significantly longer than the bacterial indicators. Only somatic coliphages and bacteriophages infecting Bacteroides persisted longer than the viruses. These results explain the numbers of enteroviruses and indicators in bathing waters attending the numbers usually found in sewage in the area. Somatic coliphages show a very good potential to predict the risk of viruses being present in bathing waters.