Ongoing quiescence in the Borborema Plateau Plague focus (Paraiba, Brazil)

Abstract

Plague is a zoonosis caused by Yersinia pestis, whose cycle is based on a reservoir system composed of mammals and their fleas. Its transmission cycle presents long enzootic periods with undetected cases, sometimes misleading that the cycle is extinct. While surveillance activities in Brazil are being carried out only in some focal areas, the serologic results confirm the persistence of Y. pestis in all monitored areas. We studied the small mammal assembly and Y. pestis presence in the Borborema Plateau Focus within the state of Paraíba, which staged the last Brazilian plague outbreak (1986-1987), through an inventory and Y. pestis detection survey of small mammals in peridomestic and sylvatic areas from two municipalities in the state of Paraíba. The field sampling captured 45 specimens (27 marsupials, 18 rodents), of 10 species. Only two species (one marsupial, one rodent) were captured in both peridomestic and sylvatic ecotopes. The sylvatic ecotope had higher richness and abundance. No evidence of circulation of the pathogen was detected, however, this result does not discard the necessity of continuous epidemiological surveillance due to the risk of rekindling the foci after long dormant periods, especially given the current epidemiological transition occurring on a Global scale.

Spatial and Temporal Distribution of Rodents during the Epizootic and Enzootic Periods of Plague, with a Focus on Exu, Northeastern Brazil

“…Practically since the arrival of the plague in Brazil in 1899, during the third pandemic, a surveillance and control program adjusted to the epidemiological situation, ecological and demographic characteristics and scientific and technological conditions has been carried out [7,10,17]. For several decades, the rodents were trapped for the detection of the plague bacillus and/or anti-plague antibodies [22,23,29]. The surveys among the rodents were discontinued in 2007 due to new evidence that the serological survey of plague antibodies among roaming dogs is a more efficient and cost-effective tool for plague surveillance [17,20].…”

“…The animal capture and handling methods varied according to the recommendations in each period, and further details can be found in the original publications. In short, the rodent and flea collection was carried out overnight, using rodent live traps (Chauvancy, Tomahawk, and Sherman); the trapped animals were brought to a field processing site for the collection of ectoparasites, sexing, and identification to species or genus, then they were either kept in quarantine until death or euthanized [ 18 , 19 , 20 , 21 , 22 , 23 ]. In the period between 1966 and 1995, only the data about the number of animals collected per year in the municipality was available, without specifying the locality.…”

Spatial and Temporal Distribution of Rodents During Active and Quiescent Periods in the Plague Focus in Exu, Northeastern Brazil

“…Practically since the arrival of the plague in Brazil in 1899, during the third pandemic, a surveillance and control program adjusted to the epidemiological situation, ecological and demographic characteristics and scientific and technological conditions has been carried out [7,10,17]. For several decades, the rodents were trapped for detection of the plague bacillus and/or antiplague antibodies [22][23][24]. The surveys among the rodents were discontinued in 2007 due to new evidences that serological survey of plague antibodies among roaming-dogs is a more efficient and cost effective tool for plague surveillance [17].…”

“…Data on rodent collection was obtained by consulting the original documents available at the Nacional Reference Service of Plague (Serviço de Referencia Nacional de Peste: SRP) from the Institute Aggeu Magalhães (IAM), FIOCRUZ PE located at Recife, PE, Brazil. Animal capture and handling methods were performed as previously described [18][19][20][21][22][23].…”

The changing triad of plague in Uganda: invasive black rats(Rattus rattus), indigenous small mammals, and their fleas

“…Over the interval from 2008–2016, a total of 255 suspected cases were reported in the WNR, of which about one‐third were later laboratory‐confirmed by bacterial culture with temperature specific bacteriophage lysis or by paired serology, with the remainder testing negative or not confirmed (i.e., no convalescent follow‐up serology obtained) (Forrester et al 2017). The number of reported human cases has dropped noticeably in recent years, presumably reflecting cyclic fluctuations or extended periods of localized quiescence within the human population that are typical of many plague foci (Pollitzer 1954, Pollitzer 1966, Dennis 1998, Carniel 2008, Zeppelini et al 2018).…”