Rodent hosts and flea vectors in Brazilian plague foci: a review

Abstract

Plague, caused by the Yersinia pestis bacterium, has several foci scattered throughout a large area from the Brazilian territory that ranges from the Northeastern State of Ceará to the Southeastern State of Minas Gerais and another separated area at the State of Rio de Janeiro. This review gathers data from plague control and surveillance programs on the occurrence and geographic distribution of rodent hosts and flea vectors in the Brazilian plague areas during the period of from 1952 to 2019. Furthermore, we discuss how the interaction between Y. pestis and some rodent host species may play a role in the disease dynamics. The absence of human cases nowadays in Brazil does not mean that it was eradicated. The dynamics of plague in Brazil and in other countries where it was introduced during the 3rd pandemic are quite alike, alternating epidemics with decades of quiescence. Hence, it remains an important epidemic disease of global concern. The existence of a large animal reservoir and competent vectors demonstrate a need for continuous surveillance to prevent new outbreaks of this disease in humans.

Spatiotemporal analysis of bubonic plague in Pernambuco, northeast of Brazil: Case study in the municipality of Exu

“…The few cases in the contiguous plains were limited to a 30-50 km zone neighboring the Chapada slopes. This is a congenial ecosystem for the coexistence of the wild rodent reservoirs of the bacteria, the flea vectors and the humans [21].…”

“…In the second epidemics, which counted the largest number of cases (193-72.3% of cases), the plague was already disseminated practically throughout all the municipality territory. In this period the plague was well established among the wild fauna [21]. The rodent Necromys lasiurus is the most common wild rodent, the most frequently infected by plague and carrying infected fleas (Polygenis bolhsi jordani and P. tripus) which played likely the more important role in the spread of plague and the human cases [9,18,20].…”

“…It was hypothesized that during the quiescence period the infection could remain in the nature in an enzootic form as a low-level circulation of the rodent-flea-rodent cycle with more time in the fleas' organism or in the rodents as a chronic form of the plague. It is also postulated that the bacteria would endure inside the burrows of certain rodent species, where the microclimate would allow its survival in debris from dead animals, in the soil contaminated with flea feces and in soil parasites [9,14,21,26].…”

Plague reservoir species throughout the world

“…2015; Reis Da Silva Fernandes et al . 2020), taxonomically outdated (Pollitzer 1960; Gratz 1999), or incomplete in their description of the systematic methodology used (Sludskyi 2014b; Dubyanskiy & Yeszhanov 2016). Different species, as well as different populations of particular species show a variance in susceptibility, mortality, and life history, and might play a different role in plague epidemiological cycles.…”

Reflections from the president of the International Society of Zoological Sciences: the zoology of zoonotic infectious diseases

“…2021; Reis da Fernandes et al . 2021). The special subsection on plague furthermore addresses questions regarding the effect of soil temperature and moisture on the suitability of sustaining the presence of a plague reservoir (Pauling et al .…”