West Nile virus is a widely spread arthropod-born virus, which has mosquitoes as vectors and birds as reservoirs. Humans, as dead-end hosts of the virus, may suffer West Nile Fever (WNF), which sometimes leads to death. In Europe, the first large-scale epidemic of WNF occurred in 1996 in Romania. Since then, human cases have increased in the continent, where the highest number of cases occurred in 2018. Using the location of WNF cases in 2017 and favorability models, we developed two risk models, one environmental and the other spatio-environmental, and tested their capacity to predict in 2018: 1) the location of WNF; 2) the intensity of the outbreaks (i.e. the number of confirmed human cases); and 3) the imminence of the cases (i.e. the Julian week in which the first case occurred). We found that climatic variables (the maximum temperature of the warmest month and the annual temperature range), human-related variables (rain-fed agriculture, the density of poultry and horses), and topo-hydrographic variables (the presence of rivers and altitude) were the best environmental predictors of WNF outbreaks in Europe. The spatio-environmental model was the most useful in predicting the location of WNF outbreaks, which suggests that a spatial structure, probably related to bird migration routes, has a role in the geographical pattern of WNF in Europe. Both the intensity of cases and their imminence were best predicted using the environmental model, suggesting that these features of the disease are linked to the environmental characteristics of the areas. We highlight the relevance of river basins in the propagation dynamics of the disease, as outbreaks started in the lower parts of the river basins, from where WNF spread towards the upper parts. Therefore, river basins should be considered as operational geographic units for the public health management of the disease.

Dengue is a viral disease transmitted by mosquitoes. The rapid spread of dengue could lead to a global pandemic, and so the geographical extent of this spread needs to be assessed and predicted. There are also reasons to suggest that transmission of dengue from non-human primates in tropical forest cycles is being underestimated. We investigate the fine-scale geographic changes in transmission risk since the late 20th century, and take into account for the first time the potential role that primate biogeography and sylvatic vectors play in increasing the disease transmission risk. We apply a biogeographic framework to the most recent global dataset of dengue cases. Temporally stratified models describing favorable areas for vector presence and for disease transmission are combined. Our models were validated for predictive capacity, and point to a significant broadening of vector presence in tropical and non-tropical areas globally. We show that dengue transmission is likely to spread to affected areas in China, Papua New Guinea, Australia, USA, Colombia, Venezuela, Madagascar, as well as to cities in Europe and Japan. These models also suggest that dengue transmission is likely to spread to regions where there are presently no or very few reports of occurrence. According to our results, sylvatic dengue cycles account for a small percentage of the global extent of the human case record, but could be increasing in relevance in Asia, Africa, and South America. The spatial distribution of factors favoring transmission risk in different regions of the world allows for distinct management strategies to be prepared.

W est Nile virus (WNV) is one of the most widespread of the arboviruses because of the translocation of the virus by migratory birds (1-3). Since its initial detection in Uganda in 1937 (4), WNV has spread throughout much of Africa (5,6), Europe (7), West Asia (8), Oceania (9), and the Americas (10,11). The enzootic cycle is maintained between birds (the reservoirs) and mainly mosquitoes (the vectors), whereas humans are accidental dead-end hosts (Figure 1). Other mammals such as horses, dogs, camels, and goats are also accidental dead-end hosts for WNV (12). The role of animal monitoring in the surveillance of WNV outbreaks is critical because detecting the virus in animals can help to anticipate its transmission to humans. Moreover, domestic animals such as horses (13) and poultry ( 14) have been used as sentinels for human cases. Furthermore, wild birds such as crows have been used to define the geographic and temporal limits of WNV in North America (15).Because WNV does not produce specific clinical symptoms, WNV infection can be mistaken for other infectious diseases and toxins ( 16). WNV outbreaks can easily be attributed to other arbovirus diseases that are more common and result in greater human illness in an area. For this reason, any evidence regarding the presence of WNV in an area is important to ensure monitoring of the risk for humans contracting the disease caused by WNV. Thus, all WNV reports should serve as suitable input data for pathogeographic analyses (17) aimed at mapping the areas at risk for WNV transmission to humans.We conducted a bibliographic review of the detection of WNV in animals in Africa. Next, we applied biogeographic methods to create empirical models on the basis of the virus lifecycle to identify zones that are environmentally favorable for the circulation of WNV in Africa. Moreover, the models were used to ascertain the potential risk for transmission of WNV to animals (epizootic processes) and humans (epidemic processes), even in regions where WNV has not yet been detected. Materials and Methods Data Sources and Search StrategyWe performed a literature search in the GIDEON database (18) for 48 countries and territories of Africa (Figure 2), using "West Nile fever" and country names as keywords. For countries that had name changes since 1937, when WNV was first described, we also searched for the ancient names or names that they were otherwise known by; for example, Equatorial Guinea (formerly Spanish Guinea), Saharawi Arab Democratic Republic (Western Sahara), and Côte d'Ivoire (Ivory Coast). We excluded the island countries and territories of Africa from this analysis because WNV probably would be enzootic and independent of the annual movements of migratory birds. The size and isolation of some of these island countries and territories would deserve an independent approach to study WNV (19). We complemented

Crises and disasters affect the numbers of people traveling either for tourism or other reasons. Many studies have been published on the effects of such events on travel, especially on tourism, and based on the arrivals or departures of travelers to or from countries. Our aim was to assess the influence of these events on the demand for pre-travel medical consultation in an International Vaccination Centre (IVC). Data on 94683 international travelers who visited 113529 international destinations attended at the IVC of Malaga (Spain) during 2000–2017 were studied. A descriptive and time series analyses was conducted. The demand to IVC was 3.47 times higher in 2017 than in 2000. The increase has not been the same for all destinations: Travel to South-East Asia and Western Pacific World Health Organization (WHO) regions has multiplied by 10, while in the same period, Africa WHO region has declined from 36% to 20% of total demand. Thailand, India and Brazil were the countries with the highest demand (21% of all pre-travel consultations). We found out three periods, concurrent with some socioeconomic or health events, in which the number of travellers attend decline with respect to the previous years, or the growth was very slow. Growth in the demand for pre-travel medical advice in parallel with a foreseeable increase in the number of travelers is expected. Pre-travel medical services must be adapted to this increase. This study of the trend of demand for pre-travel medical information should new related problems to travel to be identified and quantified, and should assist improvement of policies and programs aimed at care of travelers.

Travelers with preexisting diseases or chronic conditions may be more susceptible to travel-related health risks. They may, therefore, require more attention from specialist travel medicine providers. Our objective was to examine a group of international travelers in Malaga, Spain, quantify the proportion of travelers suffering from chronic conditions, and understand the characteristics of this group. A representative sample of travelers requesting pretravel medical advice at one travel clinic were asked about their preexisting chronic conditions and any immunosuppression. Additional demographic variables were used in an analysis of bivariate correlations. We used a binary logistic regression analysis to identify relationships between independent variables (age, gender, type of trip, travel duration, and destination) and the presence or absence of chronic conditions in travelers. Of the sample of 1,196 travelers, 258 (21.6%) reported having preexisting chronic conditions and 72 (6%) had two or more chronic conditions. Twenty-four of the travelers with chronic conditions (9%) were immunocompromised because of the disease or treatment. The two most common chronic conditions were cardiovascular disease and chronic respiratory conditions (36.8% and 17.1%, respectively). The chronic condition increased by 6.7% for every year of increased age. Travelers with chronic conditions are older, travel mainly to visit friends and relatives, and take shorter trips. More than half of travelers visiting (55.8%) needed more attention from the travel medicine practitioner because of their preexisting chronic conditions, age, or type of travel. Surveillance data based on the population of people traveling would be helpful to provide better advice to travelers.