Plague
Version: November 2025
Introduction
Plague is an infectious disease caused by the bacterium Yersinia pestis. Known for its historic influence, including the Black Death in the 14th century, plague primarily affects rodents and is transmitted to humans via flea bites. Human-to-human transmission can occur through direct contact or respiratory droplets in the case of pneumonic plague. There are three main forms: bubonic, septicemic, and pneumonic, each with distinct symptoms and severity levels. Bubonic is characterized by swollen lymph nodes, septicemic by bloodstream infection, and pneumonic by lung involvement. Prompt diagnosis and treatment with antibiotics are essential to reduce mortality.
Highlights
- A fluctuating pattern of plague cases was observed from 2016 to 2023, with sporadic outbreaks and varying numbers of fatalities, peaking primarily during mid-year months.
- A notable increase in cases occurred in 2023, with August recording the highest surge of four cases, demonstrating periodic upticks in transmission.
- From 2024 onwards, plague incidence markedly reduced, suggesting effective containment measures or natural ebbing of outbreaks, with no cases reported in 2025.
- Overall, the plague situation in mainland China appears stable post-2023, with the potential for occasional outbreaks necessitating continued vigilance.
Analysis
Cases Analysis
The data on plague in the Chinese mainland from 2015 to 2025 shows sporadic and low-level occurrences of the disease, with most months reporting zero cases and deaths, indicating effective control. Notable outbreaks occurred in June 2016, December 2017, September 2019, November 2019, and August 2023, among other isolated months. Cases in December 2017, September 2019, and August 2023 were accompanied by deaths, suggesting instances of lethal outbreaks. November 2019 saw a relatively higher occurrence with four cases but no deaths, indicating successful containment despite the sudden increase.
There is no consistent seasonal pattern for these outbreaks, appearing at various times without clear annual trends. Peaks in cases during November and December 2019, August 2020, and late summer months in 2022 and 2023 hint at environmental or social factors affecting outbreaks more than a seasonal cycle. Despite isolated months with higher incidences and occasional mortality, control measures have largely prevented widescale transmission. Increased vigilance is necessary where higher case numbers and deaths occur, underscoring the importance of continued monitoring and quick response to small outbreaks. The pattern reflects strong management overall while highlighting areas for potential improvement in anticipation of when localized outbreaks occur with greater severity.
Deaths Analysis
The reported data on plague in the Chinese mainland reveals a sporadic but low incidence of the disease from November 2015 to October 2025, with most months showing zero cases and deaths. When cases do appear, they sometimes lead to fatalities, highlighting the acute risk that accompanies outbreaks. Notably, in certain months, such as December 2017, September 2019, August 2020, and August 2023, reported cases coincided with deaths, illustrating the need for vigilance and rapid response to mitigate mortality risks.
The occurrence of deaths is not consistently linked to an increase in cases; however, instances like in November 2019 with four cases and August 2020 with three cases leading to two deaths, underscore periods where intensified exposure and transmission might have occurred. Despite some months reporting higher cases, such as August 2023 with four cases, the death rate did not show a proportional rise. This variability may be due to differences in transmission patterns, management strategies, or strain virulence influencing human outcomes during these periods.
Overall, while plague mortality remains low, the data underscores the importance of ongoing surveillance and robust public health strategies to swiftly address any outbreak potential, ensuring public safety and minimizing the impact when cases do arise.