Plague deaths reported in Ambohidratrimo district: There have been reports of three deaths in the last week of December, and the total cases are 5. The suspicion of plague is based on symptoms, no confirmatory tests have been done with no official reports.
The previous outbreak was reported in the Arivonimamo district in the municipality of Miandrandra in September 2021. Out of the confirmed cases, 19 were of pneumonic plague, and 3 were of bubonic plague. Despite the frequency, every outbreak is a cause of concern. The outbreak triggered an animal surveillance drive by the Health Authorities in collaboration with the Pasteur Institute of Madagascar. The alert threshold for carriage of Yersinia pestis in rats is 1% but it was found to be 1.3% during the surveillance with a below threshold pullicidal index of 1.7 (pullicidal index is the ratio between the total number of fleas collected from rats captured over the total number of rats captured). The close contacts were given chemoprophylaxis with Doxycycline or Cotrimoxazole.
However, in the year 2017, the country experienced an epidemic of the deadly pneumonic plague affecting major cities of the country. It is transmitted by droplets or if an untreated bubonic plague case experiences bacteremia affecting the lungs. The main reservoir is the black rat (Rattus rattus), and two main flea species (Xenopsylla cheopsis, which is found all over the world, and Synopsyllus fonquerniei, an endemic species). The disease affinity in highlands is linked to the absence of S. fonquerniei below 800m altitude.
Madagascar has experienced several outbreaks of bubonic and pneumonic plague in the 21st century and is counted under countries endemic for plague by WHO because of frequent outbreaks. It follows a seasonal trend with recrudescence from September to April. Between 200 to 400 cases are notified each year and they are limited to the central highlands of the country. Its National Strategy for the prevention and control of plague has been in place since 1993, leading to a steady decline in incidence rate over the years.
The temporal intersection of such instances with COVID-19 puts a burden on the health system. The country has been experiencing a food crisis due to instabilities brought about by the pandemic adding to the ongoing financial stress and health inequities.
Plague is a notifiable disease as per International Health Regulations 2005 and is also known as Black Death. The risk stratification for the last outbreak was categorized to be low risk at the global level. However, a recent instance of mpox virus jumping continental borders points to not taking endemicity for granted.
