Rodent-Proof Wall: An Efficient Physical Method for Controlling Rodents and its Efficiency Statistics.

Rodent damage poses a significant threat to crops, human life, and health. Compared to chemical rodent control, such as placing poisonous baits, it is more economical and environmentally friendly to use physical methods, such as building a rodent-proof wall. This study introduces a method of physically controlling harmful rodents and four methods of calculating the effect of rodents control. To understand the controlling effect of the rodent-proof wall, an investigation was conducted on the Dongting Lake beach and corresponding farmland in the embankment in April and July 2012. Our findings illustrated that the density of the reed vole Microtus fortis in the farmland with rodent-proof walls was 0.52%, significantly lower than that in the farmland without rodent-proof walls (1.76%) after artificial trapping and drug extermination (χ2 = 3.900, P = 0.048). The density of M. fortis that had migrated into the farmland in dikes with a rodent-proof wall decreased by 98.53%, significantly higher than the decrease of density in dikes without a rodent-proof wall (86.61%) (χ2 = 11.060, P = 0.01). The results demonstrated the effectiveness of rodent-proof wall control. Therefore, building a rodent-proof wall should be advocated and vigorously promoted to prevent the migration of rodents into the Dongting Lake area and similar environments, as they cause harm.

Defining the hidden burden of disease in rural communities in Bangladesh, Cambodia and Thailand: a cross-sectional household health survey protocol.

INTRODUCTION: In low-income and middle-income countries in Southeast Asia, the burden of diseases among rural population remains poorly understood, posing a challenge for effective healthcare prioritisation and resource allocation. Addressing this knowledge gap, the South and Southeast Asia Community-based Trials Network (SEACTN) will undertake a survey that aims to determine the prevalence of a wide range of non-communicable and communicable diseases, as one of the key initiatives of its first project-the Rural Febrile Illness project (RFI). This survey, alongside other RFI studies that explore fever aetiology, leading causes of mortality, and establishing village and health facility maps and profiles, will provide an updated epidemiological background of the rural areas where the network is operational. METHODS AND ANALYSIS: During 2022-2023, a cross-sectional household survey will be conducted across three SEACTN sites in Bangladesh, Cambodia and Thailand. Using a two-stage cluster-sampling approach, we will employ a probability-proportional-to-size sample method for village, and a simple random sample for household, selection, enrolling all members from the selected households. Approximately 1500 participants will be enrolled per country. Participants will undergo questionnaire interview, physical examination and haemoglobin point-of-care testing. Blood samples will be collected and sent to central laboratories to test for chronic and acute infections, and biomarkers associated with cardiovascular disease, and diabetes. Prevalences will be presented as an overall estimate by country, and stratified and compared across sites and participants' sociodemographic characteristics. Associations between disease status, risk factors and other characteristics will be explored. ETHICS AND DISSEMINATION: This study protocol has been approved by the Oxford Tropical Research Ethics Committee, National Research Ethics Committee of Bangladesh Medical Research Council, the Cambodian National Ethics Committee for Health Research, the Chiang Rai Provincial Public Health Research Ethical Committee. The results will be disseminated via the local health authorities and partners, peer-reviewed journals and conference presentations. TRIAL REGISTRATION NUMBER: NCT05389540.

Paper mulberry leaves as a potential sterilant: evidence from Microtus fortis-a laboratory study.

Introduction: The Yangtze vole (Microtus fortis) is a small herbivorous rodent that usually causes damage to crops and forests in China. Various measures were used to control their population including chemical rodenticides. However, rodenticides may cause secondary damage to the environment and the ecosystem. Therefore, the development of new rodent sterilants is urgent. Considering that some compounds of paper mulberry leaves have been verified that can inhibit the biosynthesis of sexual hormone, we aimed to explore the antifertility effect of paper mulberry leaves on M. fortis. Methods: In this study, voles were divided into three groups including a male group, a female group, and a breeding group, and paper mulberry leaves were added into basal fodder of voles maintained in laboratory, of which the proportion of leaf weight was 50%. In each group, voles were fed with mixed fodder as treatment (BP) and voles were fed with basal fodder as contrast (CK). Results and discussion: After feeding for more than 1 month, the results indicated that paper mulberry leaves attracted voles to feed, but inhibited their growth and reproduction. Since the second week, food intakes of BP have been significantly higher than CK (p< 0.05). However, weights of voles in male and female groups were 72.283 ± 7.394 g and 49.717 ± 2.278 g in the fifth week, and both were significantly reduced compared with their original weight (p< 0.05). Meanwhile, testicular volumes of male voles fed with BP were significantly smaller than CK (former: 318.000 ± 44.654 mm3, latter: 459.339 ± 108.755 mm3); the testosterone level, sperm number, and vitality of BP were obviously weaker than CK. Female uteruses and oophoron of BP grew slower, and the organ coefficients of uterus and oophoron fed BP were both significantly lower than CK (p< 0.05). The first reproduction of BP couple voles spent 45 days, while CK spent only 21 days. These results suggest that paper mulberry leaves could be the potential resource to produce sterilants to control rodent populations by delaying their sexual growth and reproduction. If it was practical, the apparent advantages of paper mulberry are that it is an abundant resource and the inhibitory effect could be effective in both male and female individuals. Our conclusion also supports the transformation of rodent management from lethal management to fertility control, which would be more ecologically friendly to agriculture and the ecosystem.

Cellular vimentin promotes the nuclear transport of the HBoV1 structural protein VP1u.

Human bocavirus 1 (HBoV1) is an important pathogen causing lower respiratory tract infection. The VP1 unique region (VP1u), consisting of 129 amino acids at the N-terminus of the HBoV1 structural protein VP1, is an important component of virus infection. Bioinformatics analysis predicted that HBoV1 VP1u exhibits two bipartite nuclear localization signals (NLS) and contains four basic regions (BRs). The two potential bipartite NLSs consist of BR2 and 3 and BR3 and 4, respectively. In this study, we inserted the truncated vp1u sequences into a double EGFP fusion expression vector and confirmed the vimentin (VIM)-HBoV1 VP1u interaction by mass spectrometry and immunoprecipitation. The results of our IFA analysis showed that all four VP1u BRs displayed strong nuclear transport functions. We further demonstrated that VP1u interacted with VIM and that they colocalized in the cytoplasm. VP1u expression in the cells enhanced the VIM expression, and the VP1u expression also increased upon VIM overexpression, although it was not affected by VIM knockdown. Upon VIM overexpression, VP1u nucleation was significantly enhanced, but was inhibited by VIM downregulation. These results indicate that the VP1u-VIM interaction could be involved in the nuclear transport of VP1u. VP1u nucleation might further affect HBoV1 replication and infection. This study could potentially help clarify the function of VP1u by further revealing the HBoV1 nuclear transport mechanism and provide a new approach for elucidating the molecular mechanism of HBoV1 replication.

Assessment of non-target toxicity effects of synthetic estradiol, quinestrol, in chickens.

Fertility control agents for the management of rodent populations are developing and maturing. Investigating the impacts on non-target species of consumption of these agents is essential. The present study assessed the non-target toxicity effects of quinestrol, a synthetic estrogen-based antifertility agent for managing rodent populations. Various quinestrol doses administered to male and female (n = 60 each) chickens through single oral gavage were 0 (A), 10 (B), 50 (C), and 150 (D) mg/kg body weight. Chickens were assessed for effect on body weight, weight of vital and reproductive organs, reproductive hormones, histology of reproductive organs and egg laying rates after 15, 30, and 135 days of treatment. Quinestrol did not induce mortality in chickens and its effects were time and dose dependent. The 90% egg-laying rates were delayed by 30, 60 for groups B and C compared with the control group, and group D did not reach the 90% egg-laying rate by 135 days. Reproductive organs in males and females returned to normal levels within 30 and 135 days, respectively. With the exception of the FSH concentration in group D, reproductive hormones of both sexes were similar to controls by 30 days. No other significant effects were found. The present research demonstrated the safety of quinestrol on non-target species and facilitates recommendations for the general administration of quinestrol for rodent pest management.

The impact of pulse oximetry on diagnosis, management and outcomes of acute febrile illness in low-income and middle-income countries: a systematic review.

BACKGROUND: Acute fever is a common presenting symptom in low/middle-income countries (LMICs) and is strongly associated with sepsis. Hypoxaemia predicts disease severity in such patients but is poorly detected by clinical examination. Therefore, including pulse oximetry in the assessment of acutely febrile patients may improve clinical outcomes in LMIC settings. METHODS: We systematically reviewed studies of any design comparing one group where pulse oximetry was used and at least one group where it was not. The target population was patients of any age presenting with acute febrile illness or associated syndromes in LMICs. Studies were obtained from searching PubMed, EMBASE, CABI Global Health, Global Index Medicus, CINAHL, Cochrane CENTRAL, Web of Science and DARE. Further studies were identified through searches of non-governmental organisation websites, snowballing and input from a Technical Advisory Panel. Outcomes of interest were diagnosis, management and patient outcomes. Study quality was assessed using the Cochrane Risk of Bias 2 tool for Cluster Randomised Trials and Risk of Bias in Non-randomized Studies of Interventions tools, as appropriate. RESULTS: Ten of 4898 studies were eligible for inclusion. Their small number and heterogeneity prevented formal meta-analysis. All studies were in children, eight only recruited patients with pneumonia, and nine were conducted in Africa or Australasia. Six were at serious risk of bias. There was moderately strong evidence for the utility of pulse oximetry in diagnosing pneumonia and identifying severe disease requiring hospital referral. Pulse oximetry used as part of a quality-assured facility-wide package of interventions may reduce pneumonia mortality, but studies assessing this endpoint were at serious risk of bias. CONCLUSIONS: Very few studies addressed this important question. In LMICs, pulse oximetry may assist clinicians in diagnosing and managing paediatric pneumonia, but for the greatest impact on patient outcomes should be implemented as part of a health systems approach. The evidence for these conclusions is not widely generalisable and is of poor quality.

Decentralised hepatitis C testing and treatment in rural Cambodia: evaluation of a simplified service model integrated in an existing public health system.

BACKGROUND: Direct-acting antiviral treatment for hepatitis C virus (HCV) has provided the opportunity for simplified models of care delivered in decentralised settings by non-specialist clinical personnel. However, in low-income and middle-income countries, increasing overall access to HCV care remains an ongoing issue, particularly for populations outside of urban centres. We therefore aimed to implement a simplified model of HCV care via decentralised health services within a rural health operational district in Battambang province, Cambodia. METHODS: The study cohort included adult residents (≥18 years) of the health operational district of Moung Russei who were voluntarily screened at 13 local health centres. Serology testing was done by a rapid diagnostic test using SD Bioline HCV (SD Bioline HCV, Standard Diagnostics, South Korea) with capillary blood. HCV viral load testing was done by GeneXpert (Cepheid, Sunnyvale, CA, USA). Viraemic patients (HCV viral load ≥10 IU/mL) received pretreatment assessment by a general physician and minimal treatment evaluation tests at the health operational district referral hospital. Viraemic patients who did not have additional complications received all HCV care follow-up at the local health centres, provided by nursing staff, and patients who had decompensated cirrhosis, previously treated with a direct-acting antiviral, HBV co-infection, or other comorbidities requiring observation continued receiving care at the referral hospital with a general physician. Patients deemed eligible for treatment were prescribed oral sofosbuvir (400 mg) and daclatasvir (60 mg) once a day for 12 weeks, or 24 weeks for patients with decompensated cirrhosis or those previously treated with a direct-acting antiviral. HCV cure was defined as sustained virological response at 12 weeks after treatment (HCV viral load <10 IU/mL). Patients were assessed for serious and non-serious adverse events at any time between treatment initiation and 12 weeks post-treatment testing. FINDINGS: Between March 12, 2018, and Jan 18, 2019, 10 425 residents (ie, 7·6% of the estimated 136 571 adults in the health operational district of Moung Russei) were screened. Of those patients screened, the median age was 44 years (IQR 31-55) and 778 (7·5%) were HCV-antibody positive. 761 (97·8%) of 778 antibody-positive patients received HCV viral load testing, and 540 (71·0%) of those tested were HCV viraemic. Among these 540 patients, linkage to treatment and follow-up care was high, with 533 (98·7%) attending a baseline consultation at the HCV clinic, of whom 530 (99·4%) initiated treatment. 485 (91·5%) of 530 patients who initiated treatment received follow-up at a health centre and 45 (8·5%) were followed up at the referral hospital. Of the 530 patients who initiated direct-acting antiviral therapy, 515 (97·2%) completed treatment. Subsequently, 466 (90·5%) of 515 patients completed follow-up, and 459 (98·5%) of 466 achieved a sustained virological response at 12 weeks after treatment. Two (0·4%) adverse events (fatigue [n=1] and stomach upset [n=1]) and five (0·9%) serious adverse events (infection [n=2], cardiovascular disease [n=1], and panic attack [n=1], with data missing for one of the causes of serious adverse events) were reported among patients who initiated treatment. All serious adverse events were deemed to be unrelated to therapy. INTERPRETATION: This pilot project showed that a highly simplified, decentralised model of HCV care can be integrated within a rural public health system in a low-income or middle-income country, while maintaining high patient retention, treatment efficacy, and safety. The project delivered care via accessible, decentralised primary health centres, using non-specialist clinical staff, thereby enhancing the efficient use of limited resources and maximising the potential to test and treat individuals living with HCV infection. FUNDING: Médecins Sans Frontières.

Defining the burden of febrile illness in rural South and Southeast Asia: an open letter to announce the launch of the Rural Febrile Illness project.

In rural areas of South and Southeast Asia malaria is declining but febrile illnesses still account for substantial morbidity and mortality. Village health workers (VHWs) are often the first point of contact with the formal health system, and for patients with febrile illnesses they can provide early diagnosis and treatment of malaria. However, for the majority of febrile patients, VHWs lack the training, support and resources to provide further care. Consequently, treatable bacterial illnesses are missed, antibiotics are overused and poorly targeted, and patient attendance wanes along with declining malaria. This Open Letter announces the start of a new initiative, the Rural Febrile Illness (RFI) project, the first in a series of projects to be implemented as part of the South and Southeast Asian Community-based Trials Network (SEACTN) research programme. This multi-country, multi-site project will run in Bangladesh, Cambodia, Lao PDR, Thailand, and Myanmar. It will define the epidemiological baseline of febrile illness in nine remote and underserved areas of Asia where malaria endemicity is declining and access to health services is limited. The RFI project aims to determine the incidence, causes and outcomes of febrile illness; understand the opportunities, barriers and appetite for adjustment of the role of VHWs to include management of non-malarial febrile illnesses; and establish a network of community healthcare providers and facilities capable of implementing interventions designed to triage, diagnose and treat patients presenting with febrile illnesses within these communities in the future.

High sustained viral response rate in patients with hepatitis C using generic sofosbuvir and daclatasvir in Phnom Penh, Cambodia.

Safe and efficacious pan-genotypic direct-acting antiviral (DAA) regimens, such as sofosbuvir and daclatasvir (SOF + DCV), facilitate simplified models of care for hepatitis C virus (HCV). However, in Cambodia access to HCV testing and treatment has typically been low. In response, Médecins Sans Frontières (MSF) implemented a HCV testing and treatment pilot project in Phnom Penh, Cambodia in 2016. This project provides the first real-world evidence of SOF + DCV effectiveness across a large patient cohort using a simplified care model in Cambodia. Patients treated with SOF + DCV from September 2016 to June 2019 were included in the analysis. Medical standard operational procedures (SOPs) were simplified significantly across the study period. Treatment effectiveness was assessed by sustained viral response at 12 weeks post-treatment (SVR12) according to a modified intention-to-treat methodology. Treatment safety was assessed by clinical outcome and occurrence of serious and nonserious adverse events (S/AE). Of 9158 patients, median age was 57 years and 39.6% were male. At baseline assessment, 27.2% of patients had compensated cirrhosis and 2.9% had decompensated cirrhosis. Genotype 6 was predominant (53.0%). Among patients analysed according to modified intention to treat (n = 8525), treatment effectiveness was high, with 97.2% of patients achieving SVR12. Occurrence of SAE was low (0.7%). Treatment effectiveness and safety was not affected by the iterative simplification to treatment modality. In conclusion, in this large treatment cohort in Phnom Penh, Cambodia, the SOF + DCV regimen showed high rates of treatment effectiveness and safety across patient sub-groups and during progressive simplification.

Evidence for the paternal mitochondrial DNA in the crucian carp-like fish lineage with hybrid origin.

In terms of taxonomic status, common carp (Cyprinus carpio, Cyprininae) and crucian carp (Carassius auratus, Cyprininae) are different species; however, in this study, a newborn homodiploid crucian carp-like fish (2n=100) (2nNCRC) lineage (F1-F3) was established from the interspecific hybridization of female common carp (2n=100)×male blunt snout bream (Megalobrama amblycephala, Cultrinae, 2n=48). The phenotypes and genotypes of 2nNCRC differed from those of its parents but were closely related to those of the existing diploid crucian carp. We further sequenced the whole mitochondrial (mt) genomes of the 2nNCRC lineage from F1 to F3. The paternal mtDNA fragments were stably embedded in the mt-genomes of F1-F3 generations of 2nNCRC to form chimeric DNA fragments. Along with this chimeric process, numerous base sites of F1-F3 generations of 2nNCRC underwent mutations. Most of these mutation sites were consistent with the existing diploid crucian carp. Moreover, the mtDNA organization and nucleotide composition of 2nNCRC were more similar to those of the existing diploid crucian carp than those of the parents. The inheritable chimeric DNA fragments and mutant loci in the mt-genomes of different generations of 2nNCRC provided important evidence of the mtDNA change process in the newborn lineage derived from hybridization of different species. Our findings demonstrated for the first time that the paternal mtDNA were transmitted into the mt-genomes of homodiploid lineage, which provided new insights into the existence of paternal mtDNA in the mtDNA inheritance.

A spatiotemporal meta-analysis of HIV/syphilis epidemic among men who have sex with men living in mainland China.

BACKGROUND: Geographic differences in HIV, syphilis and condomless sex among men who have sex with men in China remained unknown. We aimed to elucidate these spatiotemporal changing patterns in China. METHODS: We conducted a spatiotemporal meta-analysis. We searched four databases for studies conducted between 2001 and 2015. We included studies that reported original data of HIV/syphilis prevalence in China, the study's area/province, and period of data collection. We grouped studies into six regions and four time periods. We examined the changing patterns of national and regional prevalence of HIV, syphilis and condomless sex. RESULTS: Search results yielded 2119 papers, and 272 were included in the meta-analysis. The sample sizes of the studies ranged from 19 to 47,231. National HIV prevalence increased from 3.8% (95% CI 3.0-4.8) in 2001-07 to 6.6% (5.6-7.7) in 2013-15. In most regions, the rise occurred before 2010 and the HIV prevalence remained relatively stable afterwards, except for the Northwest which showed a considerable increase since 2008. National syphilis prevalence decreased from 12.3% (10.2-14.9) in 2001-07 to 7.1% (5.6-8.9) in 2013-15. CONCLUSIONS: The trends of HIV and syphilis infections have been effectively curbed in MSM in most regions of China. Continuous efforts, particularly promotion of condom use, are needed to further reduce these infections.

[Impact of deep slow-wave sleep deprivation on oxidative stress response of the testis tissue in rats].

OBJECTIVE: To investigate the influence of deep slow-wave sleep deprivation on the oxidative stress of testicular tissue in rats. METHODS: Thirty-six 5-week-old male Wistar rats were equally randomized into deep slow-wave sleep deprivation group (SD1), deep slow-wave sleep and duration sleep deprivation group ( SD2), and a cage control group (CC). The rat model of deep slow-wave sleep deprivation was established using the flowerpot technique. The rats in the SD1 group were interfered every 24 minutes and deprived of 12 hours of sleep at night, those in the SD2 group deprived of 8 minutes of sleep at an interval of 24 minutes and 12 hours of sleep at night, and those in the CC group exposed to 12 hours of daylight and 12 hours of darkness. After 28 days, all the rats were executed for measurement of the testis volume and protein content, determination of the methane dicarboxylic aldehyde (MDA) level and activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and observation of the pathological changes in the testicular tissue under the microscope. RESULTS: Compared with the CC group, the rats in the SD1 and SD2 groups showed significantly reduced body weight (ï¼»268.5 ± 1.6ï¼½ vs ï¼»248.1 ± 25.1ï¼½andï¼»232.9 ± 10.1ï¼½g, P<0.05) and increased relative testis mass (ï¼»50.0 ± 1.3ï¼½ vs ï¼»57.9 ± 6.1ï¼½ and ï¼»54.9 ± 3.5ï¼½ ×10⁻², P<0.05). Statistically significant differences were found between the CC and SD2 groups in the contents of protein (ï¼»6.3 ± 1.4ï¼½ vs ï¼»4.5 ± 0.9ï¼½ gpro/L, P<0.05) and MDA (ï¼»1.1 ± 0.1ï¼½ vs ï¼»1.3 ± 0.3ï¼½ nmol/mgpro, P<0.05) and the activities of SOD (ï¼»104.3 ± 33.1ï¼½ vs ï¼»135.2 ± 26.9ï¼½ U/mgpro, P<0.05) and GSH-Px (ï¼»15.6 ± 4.0ï¼½ vs ï¼»21.7 ± 4.3ï¼½ U/mgpro, P<0.05), but not between the CC and SD1 groups (P>0.05). The lumens in the testis were narrowed, with obvious hyperplasia, hyperemia and edema in the peripheral interstitial tissue, but no significant pathologic changes were observed in the testis tissue of the SD1 group. CONCLUSIONS: Long-term deprivation of deep slow-wave sleep impairs the structure of the testis tissue and induces oxidative stress response in rats.

Associations between psychological characteristics and indicators of metabolic syndrome among Chinese adults.

Current knowledge about the relationship between psychological characteristics and metabolic syndrome (MetS) components is limited in Asian populations. The purpose of this study is to investigate linkages between physiological markers of MetS and life satisfaction, hostility, and depression in Chinese adults. Secondary analyses were conducted using cross-sectional data from parents of randomly selected middle school students participating in a pilot study in Qingdao, China. Among 440 parents who consented to participate (237 women, 203 men), 368 provided valid responses in all three categories of psychological characteristics, and only those subjects were included in these analyses. General linear models and logistic regressions were run separately by gender, controlling for covariates. Among women, life satisfaction was inversely associated with triglyceride levels (p = .04), LDL-C (p < .01), risk of hypertriglyceridemia (OR[.53], p < .01), HDL-C (OR[.78], p = .03), and MetS (OR[.52], p = .03). No associations were found between life satisfaction and any psychological characteristics among men. Among women, hostility was positively associated with triglyceride level (p = .04) and risk of hypertriglyceridemia (OR[2.12], p < .05). Among men, hostility was positively associated with waist circumference (p = .04), waist-hip ratio (p < .05), and fasting plasma insulin (p < .01). Depression was not associated with any physiological measurement in either gender. These findings indicate that relationships exist between certain psychological characteristics and physiological indicators of MetS among Chinese adults, although there may be important differences between genders.

Reproductive characteristics of the Yangtze vole (Microtus fortis calamorum) under laboratory feeding conditions.

The reproductive characteristics of a laboratory population of the vole Microtus fortis calamorum were examined. Voles were allowed to breed under laboratory feeding conditions. Over a period of 3 months, 61.82% of the 110 vole pairs examined produced 3 or 4 litters. There were 1-9 voles in each litter and the mean litter size was 4.67±0.28 (mean±SE). Most litters included 3-7 young voles, accounting for 83.62% of all litters. The mean farrowing interval was 25.9 days (range from 19 to 95 days), and the most farrowing intervals were 20-25 days, accounting for 79.9% of the total. When based on litter size, the reproductive index was 6.23, but was 3.42 when based on pup survival. The survival rate of offspring to weaning was 55.03%. The high rate of infanticide that occurred after removal of males from cages indicates that, in the laboratory, both parents need to be present prior to weaning.

Habitat evaluation for outbreak of Yangtze voles (Microtus fortis) and management implications.

Rodent pests severely damage agricultural crops. Outbreak risk models of rodent pests often do not include sufficient information regarding geographic variation. Habitat plays an important role in rodent-pest outbreak risk, and more information about the relationship between habitat and crop protection is urgently needed. The goal of the present study was to provide an outbreak risk map for the Dongting Lake region and to understand the relationship between rodent-pest outbreak variation and habitat distribution. The main rodent pests in the Dongting Lake region are Yangtze voles (Microtus fortis). These pests cause massive damage in outbreak years, most notably in 2007. Habitat evaluation and ecological details were obtained by analyzing the correlation between habitat suitability and outbreak risk, as indicated by population density and historical events. For the source-sink population, 96.18% of Yangtze vole disaster regions were covered by a 10-km buffer zone of suitable habitat in 2007. Historical outbreak frequency and peak population density were significantly correlated with the proportion of land covered by suitable habitat (r = 0.68, P = 0.04 and r = 0.76, P = 0.03, respectively). The Yangtze vole population tends to migrate approximately 10 km in outbreak years. Here, we propose a practical method for habitat evaluation that can be used to create integrated pest management plans for rodent pests when combined with basic information on the biology, ecology and behavior of the target species.

Effect of population density on reproduction in Microtus fortis under laboratory conditions.

Between December 2011 and March 2012, the reproductive characteristics of Microtus fortis reared in the laboratory at different population densities were assessed. In all, 258 male and female voles were randomly divided into 4 groups and reared at densities of 2, 4, 6, and 8 animals per cage (sex ratio: 1:1). The results showed that the pregnancy rate (χ2 = 21.671, df = 3, P < 0.001) and first farrowing interval (F = 12.355, df = 3, P < 0.001) were significantly different among the different population density groups, but the mean litter size (mean ± SD) was not (F = 2.669, df = 3, P > 0.05). In particular, the reproductive index and sex hormone levels showed a significant difference among the different density groups studied.

Small mammal community succession on the beach of Dongting Lake, China after the Three Gorges Project.

Although the Three Gorges Project (TGP) may have affected the population structure and distribution of plant and animal communities, few studies have analyzed the effect of this project on small mammal communities. Therefore, the present paper compares the small mammal communities inhabiting the beaches of Dongting Lake using field investigations spanning a 20-year period, both before and after the TGP was implemented. Snap traps were used throughout the census. The results indicate that the TGP caused major changes to the structure of the small mammal community at a lake downstream of the dam. First, species abundance on the beaches increased after the project commenced. The striped field mouse (Apodemus agrarius) and the Norway rat (Rattus norvegicus), which rarely inhabited the beach before the TGP, became abundant (with marked population growth) once water was impounded by the Three Gorges Reservoir. Second, dominant species concentration indices exhibited a stepwise decline, indicating that the community structure changed from a single dominant species to a more diverse species mix after TGP implementation. Third, the regulation of water discharge release by the TGP might have caused an increase in the species diversity of the animal community on the beaches. A significant difference in diversity indices was obtained before and after the TGP operation. Similarity indices also indicate a gradual increase in species numbers. Hence, a long-term project should be established to monitor the population fluctuations of the Yangtze vole (Microtus fortis), the striped field mouse and the Norway rat to safeguard against population outbreaks (similar to the Yangtze vole outbreak in 2007), which could cause crop damage to adjacent farmland, in addition to documenting the succession process of the small mammal community inhabiting the beaches of Dongting Lake.

[Possible impacts of the Three Gorges Project and converting farmland into lake on the Microtus fortis population in Dongting Lake region].

The outbreak of Yantze vole (Microtus fortis) population in Dongting Lake region is closely related to the evolvement of lake beaches, because the deposition of lake sediments results in the expansion of lake beaches, which provides the possibility of the increase of the vole's population. Reclaiming farmland from lake via building cofferdams, eliminating snails by building cofferdams for eradicating schistosomiasis, and over-hunting predators in the region cause the voles becoming a pest after the 1970s. In recent years, the Three Gorges Project and the conversion from farmland into lake have had deep impacts on the environment in the Lake region. The dispatching of the down flow rate by the Project induces the expansion of the low and medium level beaches in the Lake region, while converting farmland into lake directly induces the increase of beach area, both of which expand the potential habitats of the vole's population. Therefore, more attention should be paid on the quantitative variation trend of the vole's population in the future.

[Population dynamics of Microtus fortis in Dongting Lake region and its forecasting].

The population dynamics of Microtus fortis in Yueyang, Hunan Province was studied from 1991 to 1996. M. fortis lived on the beach of the lake from early autumn to next spring, but moved to the farmland in summer when the beach was flooded. When lived on the beach, its population increased gradually. Usually, M. fortis made great damage on the crops when moved to the farmland. The population dynamics of M. fortis was different on the beach and on the farmland, and the key affecting factors were also different. Lake beach was the most suitable habitat for M. fortis. When it emerged in autumn, M. fortis moved back on it. The main breeding season of M. fortis inhabited on the beach was from October to May, and its population density increased gradually. The period between the beach emerged and been flooded determined the population size of the animal moved to farmland. Another factor was the rainfall in March. Farmland was not the suitable habitat for M. fortis. Because of the low breeding potential, high mortality and dispersal on farmland, its population density kept decreasing, and was very low in winter. The population density on farmland dropped dramatically when the lake beach emerged. The animal population was forecasted by means of regression analysis, and a linear regression equation was obtained. The predicted values matched with the real population densities of the animal in the field.