Identification of Leptospira and Bartonella among rodents collected across a habitat disturbance gradient along the Inter-Oceanic Highway in the southern Amazon Basin of Peru

Abstract

BackgroundThe southern Amazon Basin in the Madre de Dios region of Peru has undergone rapid deforestation and habitat disruption, leading to an unknown zoonotic risk to the growing communities in the area.Methodology/Principal findingsWe surveyed the prevalence of rodent-borne Leptospira and Bartonella, as well as potential environmental sources of human exposure to Leptospira, in 4 communities along the Inter-Oceanic Highway in Madre de Dios. During the rainy and dry seasons of 2014–2015, we captured a total of 97 rodents representing 8 genera in areas that had experienced different degrees of habitat disturbance. Primarily by using 16S metagenomic sequencing, we found that most of the rodents (78%) tested positive for Bartonella, whereas 24% were positive for Leptospira; however, the patterns differed across seasons and the extent of habitat disruption. A high prevalence of Bartonella was identified in animals captured across both trapping seasons (72%–83%) and the relative abundance was correlated with increasing level of land disturbance. Leptospira-positive animals were more than twice as prevalent during the rainy season (37%) as during the dry season (14%). A seasonal fluctuation across the rainy, dry, and mid seasons was also apparent in environmental samples tested for Leptospira (range, 55%–89% of samples testing positive), and there was a high prevalence of this bacteria across all sites that were sampled in the communities.Conclusions/SignificanceThese data indicate the need for increased awareness of rodent-borne disease and the potential for environmental spread along the communities in areas undergoing significant land-use change.

Emerging zoonotic diseases originating in mammals: a systematic review of effects of anthropogenic land‐use change

“…urbanisation, agricultural conversion/intensification, deforestation, and fragmentation) have the potential to increase the risk of an emergence of a bacterial zoonotic disease across the globe. For example, the relative abundance of Bartonella in rodents has been correlated with the increasing level of land disturbance and deforestation in Peru (Cortez et al 2018), risk of brucellosis increases with agricultural intensification (Ducrotoy et al 2014), and the incidence of Borrellia spp. in mammals increases with habitat fragmentation across Europe (Millins et al 2018).…”

“…Conversion of forests to agricultural land results in decreased diversity of zoonotic microparasites and rodent‐borne pathogens in South‐East Asia; however, the consequent increase in synanthropic rodents favours pathogen spread (Morand et al 2019). In South America, where deforestation rates are high, there are instances of zoonotic EIDs including microsporidia (Pereira et al 2009), Bartonella , and Leptospira (Cortez et al 2018). However, it is not clear whether microsporidia spores found in wild mammal faeces are always the result of an infection, rather than simply passing through the gastrointestinal tract (Pereira et al 2009), and the methodology used for Bartonella and Leptospira identification has limitations (Cortez et al 2018).…”

The Presence of Rodents Infected With Leptospira Bacteria in Various Countries and the Leptospirosis Potential in Humans: A Systematic Review

“…Rattus norvegicus is a species that is widespread on roads, rivers, lakes, and beaches. Rattus norvegicus habitat is in agriculture, horticulture, grasslands, forests, inland areas, and places that are rarely planted 30 . Oligoryzomys microtis is found in tropical forests and the edges of forests.…”

Seroprevalence of leptospiral antibodies in rodents from riverside communities of Santa Fe, Argentina

“…Murid rodents of the species Mus musculus, Rattus norvegicus and Rattus rattus (Muridae: Murinae) are maintenance hosts of the serovars Icterohaemorrhagiae, Copenhageni and Ballum [4,5]. In recent years, some species of South American sigmodontine rodents (Cricetidae: Sigmodontinae) were also reported as renal carriers of Leptospira [6][7][8][9][10][11][12]. Introduced and native rodent species usually cohabit and seek food and shelter in the proximity of households, becoming an important source of infection for humans and domestic animals [4,6].…”

“…Introduced and native rodent species usually cohabit and seek food and shelter in the proximity of households, becoming an important source of infection for humans and domestic animals [4,6]. Some variables related to the biology of these rodents, such as species, sex, sexual maturity or body condition, as well as rodent community composition may affect the ecology of leptospires [4,9,13]. Environmental features also can play an important role in the dynamics of leptospires influencing both the behavior of maintenance hosts and the persistence of the pathogen in water and soil [4,6].…”