Rodent-borne viruses survey in rural settlers from Central Brazil

Anthropogenic environmental changes arising from settlement and agriculture include deforestation and replacement of natural vegetation by crops providing opportunities for pathogen spillover from animals to humans. This study aimed to investigate the prevalence of rodent-borne virus infections in seven rural settlements from Midwestern Brazil. Of the 466 individuals tested 12 (2.57%) were reactive for orthohantavirus and 3 (0.64%) for mammarenavirus. These rural settlers lived under unfavorable infrastructure, socioeconomic disadvantages, and unsanitary conditions, representing a risk for rodent-borne infections. Development of public policies towards the improvement of health, sanitation and awareness of rodent-borne diseases in improvised camps and settlements is imperative, in order to reduce morbidity and mortality caused by these diseases.

Dynamics of Rodent and Rodent-borne Disease during Construction of the Three Gorges Reservoir from 1997 to 2012 / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To investigate the impact of impoundment and active public health interventions on rodent populations and rodent-borne diseases in the Three Gorges reservoir region from 1997 to 2012.</p><p><b>METHODS</b>Surveillance data from 1997 to 2012 were extracted from the Public Health Surveillance System of The Three Gorges established in 1997. Temporal changes in the incidences of hemorrhagic fever with renal syndrome (HFRS) and leptospirosis, rodent density, pathogen-carrying rates, and their correlations were analyzed.</p><p><b>RESULTS</b>The average indoor and outdoor rodent densities decreased overall from 1997 to 2012. The average densities decreased by 47.72% (from 4.38% to 2.29%) and 39.68% (from 4.41% to 2.66%), respectively, after impoundment (2003-2012) compared with before impoundment (1997-2002). The average annual incidence rates of HFRS and leptospirosis were 0.29/100,000 and 0.52/100,000, respectively, and decreased by 85.74% (from 0.68/100,000 to 0.10/100,000) and 95.73% (from 1.47/100,000 to 0.065/100,000), respectively, after impoundment compared with before impoundment. Incidences of HFRS and leptospirosis appear to be positively correlated with rodent density in the reservoir area.</p><p><b>CONCLUSION</b>This study demonstrated that rodent density and incidences of rodent-borne diseases decreased and were maintained at low levels during construction of the Three Gorges dam. Measures that reduce rodent population densities could be effective in controlling rodent-borne diseases during large-scale hydraulic engineering construction.</p>

Factors related to household rodent abundance in rodent-borne disease foci in western Yunnan / 中华流行病学杂志

Objective To analyze the factors related to the household abundance of rodents in rodent-borne disease foci in the western part of Yunnan province.Methods From July 2011 to October 2012,800 households (20 households in 1 village) were randomly selected in 40 natural villages of 10 counties in western Yunnan where rodent borne disease was endemic to conduct a study on relationship between rodent abundance and environmental factors.Five cages were placed in each household for 3 consecutive nights to capture rodents.The rodent species were identified based on their morphological characteristics.The data on potential factors related to rodent abundance were collected through questionnaires and field observation.A dataset was established by using EpiData software and the analysis was performed with hurdle regression model under R software.Results A total of 421 rodents were captured in 800 households,belonging to 9 species,6 genera,2 families,2 orders.Rattus tanezumi was the predominant species (66.03％).The final hurdle regression model showed that the probability of capturing rodents in the households where family member had high education level and the garbage was placed outside declined by 50％-68％ ; The probability of capturing rodents in the households of Dai and Yi ethnic groups increased by 2.16-2.87 times; The probability of capturing rodents in the households where rodents were observed or vegetables grown near houses increased by 1.54-1.59 times; In the households where many rodents were believed to exist,the probability of capturing rodents and the number of rodents captured increased by 1.59 and 1.84 times respectively.The number of rodents captured in the houses with cement or tile floor increased by 3.62 times.Conclusion The household abundance of rodents in the area in western Yunnan,where the rodent-borne disease survey was conducted,seemed to be closely related to the social economy status,human intervention and ecological environment.To control the abundance of rodents effectively,it is necessary to take these factors into consideration.