Differences in population parameters of Rattus norvegicus in urban and rural habitats of central Argentina

BackgroundLeptospirosis is a bacterial zoonosis caused by pathogenic Leptospira for which rats are considered as the main reservoir. Disease incidence is higher in tropical countries, especially in insular ecosystems. Our objectives were to determine the current burden of leptospirosis in Seychelles, a country ranking first worldwide according to historical data, to establish epidemiological links between animal reservoirs and human disease, and to identify drivers of transmission.MethodsA total of 223 patients with acute febrile symptoms of unknown origin were enrolled in a 12-months prospective study and tested for leptospirosis through real-time PCR, IgM ELISA and MAT. In addition, 739 rats trapped throughout the main island were investigated for Leptospira renal carriage. All molecularly confirmed positive samples were further genotyped.ResultsA total of 51 patients fulfilled the biological criteria of acute leptospirosis, corresponding to an annual incidence of 54.6 (95% CI 40.7–71.8) per 100,000 inhabitants. Leptospira carriage in Rattus spp. was overall low (7.7%) but dramatically higher in Rattus norvegicus (52.9%) than in Rattus rattus (4.4%). Leptospira interrogans was the only detected species in both humans and rats, and was represented by three distinct Sequence Types (STs). Two were novel STs identified in two thirds of acute human cases while noteworthily absent from rats.ConclusionsThis study shows that human leptospirosis still represents a heavy disease burden in Seychelles. Genotype data suggests that rats are actually not the main reservoir for human disease. We highlight a rather limited efficacy of preventive measures so far implemented in Seychelles. This could result from ineffective control measures of excreting animal populations, possibly due to a misidentification of the main contaminating reservoir(s). Altogether, presented data stimulate the exploration of alternative reservoir animal hosts.

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“…rattus was absent [ 62 ] and with reports from other countries where R . norvegicus is distributed in all habitats including rural areas [ 63 ].…”

Section: Discussionmentioning

confidence: 99%

Human leptospirosis in Seychelles: A prospective study confirms the heavy burden of the disease but suggests that rats are not the main reservoir

et al. 2017

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“…Trap success (TS) was used to estimate the relative rodent abundance as follows: number of rats trapped − 100/(number of traps − number of nights) [41]. The non-parametric Mann–Whitney [ U -test was used to compare the TS between rodent species.…”

Section: Methodsmentioning

confidence: 99%

A survey of zoonotic pathogens carried by house mouse and black rat populations in Yucatan, Mexico

et al. 2017

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SUMMARY The house mouse (Mus musculus) and the black rat (Rattus rattus) are reservoir hosts for zoonotic pathogens, several of which cause neglected tropical diseases (NTDs). Studies of the prevalence of these NTD-causing zoonotic pathogens, in house mice and black rats from tropical residential areas are scarce. Three hundred and two house mice and 161 black rats were trapped in 2013 from two urban neighbourhoods and a rural village in Yucatan, Mexico, and subsequently tested for Trypanosoma cruzi, Hymenolepis diminuta and Leptospira interrogans. Using the polymerase chain reaction we detected T. cruzi DNA in the hearts of 4·9% (8/165) and 6·2% (7/113) of house mice and black rats, respectively. We applied the sedimentation technique to detect eggs of H. diminuta in 0·5% (1/182) and 14·2% (15/106) of house mice and black rats, respectively. Through the immunofluorescent imprint method, L. interrogans was identified in 0·9% (1/106) of rat kidney impressions. Our results suggest that the black rat could be an important reservoir for T. cruzi and H. diminuta in the studied sites. Further studies examining seasonal and geographical patterns could increase our knowledge on the epidemiology of these pathogens in Mexico and the risk to public health posed by rodents.

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“…Although the Norway rat has a worldwide distribution, most studies on rat populations have been focused in temperate areas [ 10 – 15 ]. These studies have shown that reproductive parameters vary significantly among seasons or habitats (e.g.…”

Section: Introductionmentioning

confidence: 99%

“…Seasonal differences are influenced by both biotic and abiotic factors of the environment (e.g. photoperiod, food supply, and weather) that interact to regulate their growth rate and reproductive development [ 15 ]. Additionally, morphometric differences between temperate and tropical rat populations, consistent with Bergmann’s rule, add a further complication to direct generalizations of rats sampled from different latitudes [ 18 ].…”

Section: Introductionmentioning

confidence: 99%

A Two-Year Ecological Study of Norway Rats (Rattus norvegicus) in a Brazilian Urban Slum

et al. 2016

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The Norway or brown rat (Rattus norvegicus) is among the most ubiquitous of rodents. However, the lack of studies describing Norway rat populations from tropical areas have limited our understanding regarding their demography and seasonal dynamics. In this study, we describe seasonal pattern in the abundance, reproductive parameters, and morphometrics of Norway rat populations in Salvador, Brazil. Rodents were trapped over four seasonal trapping periods (2013–2014) from three valleys. A total of 802 Norway rats were trapped over the course of the study over 7653 trap-nights. Norway rat abundance was high, but there was no significant differences between seasons. The reproductive parameters (e.g. frequency of pregnant and lactating females) did not show statistical differences between seasons. Female rats collected in the rainy season were heavier and older than females from the dry season. Salvador rats had a high incidence of pregnancy and birth rate (estimated birth rate of 79 young per year) compared to previous studies. The information generated is critical for the understanding of the ecology of Norway rat, the main reservoir of Leptospira in Salvador. However, future studies examining the effect of rodent control programs aimed at reducing populations, and determining rates of recovery, will further clarify our understanding of population dynamics.

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Differences in population parameters of Rattus norvegicus in urban and rural habitats of central Argentina

Abstract: Life history characteristics are influenced by both biotic and abiotic factors of the environment. The aim of this study was to compare the life history strategies of

Cited by 16 publications

References 26 publications

Human leptospirosis in Seychelles: A prospective study confirms the heavy burden of the disease but suggests that rats are not the main reservoir

Human leptospirosis in Seychelles: A prospective study confirms the heavy burden of the disease but suggests that rats are not the main reservoir

A survey of zoonotic pathogens carried by house mouse and black rat populations in Yucatan, Mexico

A Two-Year Ecological Study of Norway Rats (Rattus norvegicus) in a Brazilian Urban Slum

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