Seasonal dynamics of typhoid and paratyphoid fever

Abstract

Typhoid and paratyphoid fever may follow a seasonal pattern, but this pattern is not well characterized. Moreover, the environmental drivers that influence seasonal dynamics are not fully understood, although increasing evidence suggests that rainfall and temperature may play an important role. We compiled a database of typhoid, paratyphoid, or enteric fever and their potential environmental drivers. We assessed the seasonal dynamics by region and latitude, quantifying the mean timing of peak prevalence and seasonal variability. Moreover, we investigated the potential drivers of the seasonal dynamics and compared the seasonal dynamics for typhoid and paratyphoid fever. We observed a distinct seasonal pattern for enteric and typhoid fever by latitude, with seasonal variability more pronounced further from the equator. We also found evidence of a positive association between preceding rainfall and enteric fever among settings 35°–11°N and a more consistent positive association between temperature and enteric fever incidence across most regions of the world. In conclusion, we identified varying seasonal dynamics for enteric or typhoid fever in association with environmental factors. The underlying mechanisms that drive the seasonality of enteric fever are likely dependent on the local context and should be taken into account in future control efforts.

Changes in historical typhoid transmission across 16 U.S. cities, 1889-1931: Quantifying the impact of investments in water and sewer infrastructures

“…Historically, typhoid fever cases peaked during late summer/early fall in the U.S. (6, 27). Yearly peaks of typhoid transmission coincide with warmer temperatures, similar to global trends (7, 28–30). This pattern may be related to the enhanced growth of the bacteria at warmer temperatures, seasonal changes in diet (i.e.…”

“…This pattern may be related to the enhanced growth of the bacteria at warmer temperatures, seasonal changes in diet (i.e. increased consumption of uncooked fruit and vegetables in summer and fall), or the increased abundance of flies that may serve as mechanical vectors of the bacteria (6, 7, 31, 32). Additional fluctuations in typhoid transmission seen in some cities might be explained by seasonal variation in rainfall, which typically peaks in spring and summer in the eastern U.S. and winter on the west coast, and can impact the water supply to a city (29, 30, 33).…”

“…In many countries, typhoid fever follows a seasonal pattern, with peak incidence occurring around the same time every year (6). Seasonality in typhoid exhibits distinct patterns by region and latitude, and can be influenced by rainfall, temperature, and climate (7). However, drivers of seasonal patterns in typhoid are not yet fully understood.…”

Early warning of some notifiable infectious diseases in China by the artificial neural network

“…In addition, the numbers of new confirmed cases of the four types of infectious diseases were used as inputs in the model. Because the numbers of cases of different diseases might have correlations and seasonal fluctuations [19][20][21][22][23][24], they were standardized in advance. After standardization was completed, the average value of each input variable should be approximately zero, there should be no correlation between variables, and covariances should be approximately equal.…”

Assessment and initial management of acute undifferentiated fever in tropical and subtropical regions

“…In many tropical areas, malaria occurs round the year. Seasonal dynamics of enteric fever are variable, with peaks after rainfall seen in northern latitudes 26. Information on ongoing outbreaks or a cluster of cases in a family or neighbourhood are useful clues to guide diagnosis.…”