The influence of temperature on the seasonality of historical plague outbreaks

Abstract

Modern plague outbreaks exhibit a distinct seasonal pattern. By contrast, the seasonality of historical outbreaks and its drivers has not been studied systematically. Here, we investigate the seasonal pattern, the epidemic peak timing and growth rates, and the association with latitude, temperature, and precipitation using a large, novel dataset of plague- and all-cause mortality during the Second Pandemic in Europe and the Mediterranean. We show that epidemic peak timing followed a latitudinal gradient, with mean annual temperature negatively associated with peak timing. Based on modern temperature data, the predicted epidemic growth of all outbreaks was positive between 11.7°C and 21.5°C with a maximum around 17.3°C. Hence, our study provides evidence that the growth of plague epidemics across the whole study region depended on similar absolute temperature thresholds. Here, we present a systematic analysis of the seasonality of historical plague in the Northern Hemisphere, and we show consistent evidence for a temperature-related process influencing the epidemic peak timing and growth rates of plague epidemics.

Climate Change Drives the Transmission and Spread of Vector-Borne Diseases: An Ecological Perspective

“…For example, the survival and reproduction range of rodents is generally 10.0–30.0 °C, while 20.0–30.0 °C is the suitable temperature range for rodent-borne disease transmission [ 35 ]. The predicted epidemic growth of plague outbreaks is positive between 11.7 °C and 21.5 °C, with a maximum around 17.3 °C [ 36 ]. With regard to mosquito-borne diseases, temperature can affect the development and survival of mosquitoes, and there is a thermal optimum which will be suppressed at either heat or cold [ 37 ]; including malaria, dengue and Zika, temperature and climate change are reported to have strong nonlinear effects on ectothermic vectors and parasites.…”

Using cementochronology to assess the seasonality of catastrophic events in medieval mass graves (Kutná Hora-Sedlec, Czechia, 14th century): Preliminary results

“…We can also get closer to interpreting the cause of mass graves by linking the results of seasonality estimation to the fact that several diseases have specific seasonal dynamics. Plague, in particular, is greatly influenced by seasonal factors [ 22 , 23 ]. Famine is usually defined as a discrete mass starvation event triggered by a food shortage [ 24 , 25 ].…”

“…These sources show that demographic crises caused by widespread and severe food scarcity culminate in the Northern Hemisphere in the winter or early spring months. Plague is the only medieval epidemic for which the temporal and geographical propagation characteristics have been studied and described [ 23 , 31 ]. The temperature plays a significant role in the timing and growth of epidemics [ 32 ].…”

“…The data composed during the time of the Medieval Black Death suggest that mortality peaked mostly during the warmer weather months between April and October [ 33 ]. This peak mortality coincides with a seasonal peak in travel and trade during this period [ 23 ] investigated seasonal patterns and the epidemic peak timing of historical plague outbreaks (mainly from the 16-19 th centuries) together with its association with latitude as a rough proxy measure for climatic conditions. They found that the typical plague season differed by latitude, and that the more northerly the location, the later the epidemic mortality peak occurred.…”

“…They found that the typical plague season differed by latitude, and that the more northerly the location, the later the epidemic mortality peak occurred. Based on the findings of [ 23 ] and the city’s latitude (49°56′54″N), Kutná Hora would fall into the category of having August–September plague mortality peaks.…”