Rodent Surveillance Research Articles

Rodent Ecology and Etiological Investigation in China: Results from Vector Biology Surveillance - Shandong Province, China, 2012-2022.

Rodents are hosts of a wide range of zoonotic disease pathogens which threaten human health. However, comprehensive investigations of rodent ecology and etiology in Shandong are lacking. Thus, we aimed to analyze rodent ecology and infection with relevant pathogens in Shandong Province, China. Rodent survey data collected from 2012 to 2022 in Shandong Province were used in this study. Rodents captured from 2020 to 2022 were identified to species and tested for pathogens. From 2012 to 2022, 4,145 rodents were captured, with an average capture rate of 0.70%. High capture rates were observed in rural residential areas and other habitats, such as farmland and forestland. Rattus norvegicus (R. norvegicus) was the dominant species, followed by Mus musculus (M. musculus). The regions with the highest capture rates of R. norvegicus were Dongying (0.82%) and Heze (0.63%), while M. musculus was more prevalent in Dongying (0.81%) and Weihai (0.56%). Rodent capture rates were highest between March and September. The positive detection rates of Hantavirus (HV), Leptospira interrogans (L. interrogans), Rickettsia typhi (R. typhi), Anaplasma phagocytophilum (A. phagocytophilum), and Francisella tularensis (F. tularensis) in rodents were 2.58%, 1.10%, 0.94%, 0.16%, and 0.19%, respectively. The rodent capture rate in human habitation environments has trended downward in Shandong Province, with R. norvegicus and M. musculus being the dominant species. Rodent infection risk from HV, L. interrogans, and R. typhi showed seasonal variation. Strengthening rodent surveillance and maintaining a low capture rate of host animals could be pivotal for preventing and controlling relevant rodent-borne diseases in high-risk areas.

Hantavirus Pulmonary Syndrome Outbreak Anticipation by a Rapid Synchronous Increase in Rodent Abundance in the Northwestern Argentina Endemic Region: Towards an Early Warning System for Disease Based on Climate and Rodent Surveillance Data.

Hantavirus pulmonary syndrome (HPS) is an American emerging disease caused by the rodent-borne virus genus Orthohantavirus (Family: Hantaviridae: Order: Elliovirales Class: Bunyaviricetes). In Argentina, almost half of the HPS infections occur in the northwestern endemic region. In this study, we monitored rodent abundance during 2022 and 2023 in three sites with different sampling methods (removal trapping, live trapping and hunted rodents by domestic cats) to evaluate their relationship with human infections. We found a similar pattern of variation in rodent abundance across time, and particularly a synchronous rise of rodent abundance that anticipated an HPS outbreak in 2023. Our dynamic regression models revealed a positive relationship between HPS cases and rodent abundance with a three-month lag, as well as rainfall with an eight-month lag. Our results provide a framework for the planning and implementation of public health prevention campaigns based on climatology and rodent monitoring. Domestic cats bringing rodents into houses can be an overlooked risk factor, particularly if viral shedding of infected rodents is magnified by stress. HPS is a disease of public health concern due to its high mortality rate, the lack of a specific therapeutic treatment and no vaccine. Thus, prevention of infections is of the utmost importance.

Evaluating climate-dependent distribution of orthohantaviruses with monitoring wild rodents: One Health Perspective†.

Orthohantaviruses, cause hemorrhagic fever with renal syndrome, nephropathia epidemica, and hantavirus pulmonary syndrome, are major public health problems all over the world. Wild rodent surveillance for orthohantaviruses is of great importance for the preparedness against these human infections and the prediction of possible outbreak regions. Thus, we aimed to screen orthohantaviruses in wild rodents in Southern Anatolia, where the area has some of the glacial period refugia in the Mediterranean Basin, and interpret their current epidemiology with climatic biovariables in comparison with previously positive regions.We trapped muroid rodents between 2015 and 2017, and screened for orthohantaviruses. Then, we evaluated the relationship between orthohantavirus infections and bioclimatic variables. In spite of the long-term and seasonal sampling, we found no evidence for Orthohantavirus infections. The probable absence of orthohantaviruses in the sampling area was further evaluated from the climatic perspective, and results led us suggest that Orthohantavirus epidemiology might be relatively dependent on precipitation levels in driest and warmest quarters, and temperature fluctuations.These initial data might provide necessary perspective on wild rodent surveillance for orthohantaviruses in other regions, and help to collect lacking data for a such habitat suitability study in a bigger scale in the future.

Systematic surveillance tools to reduce rodent pests in disadvantaged urban areas can empower communities and improve public health

Rodents are notorious pests, known for transmitting major public health diseases and causing agricultural and economic losses. The lack of site-specific and national standardised rodent surveillance in several disadvantaged communities has rendered interventions targeted towards rodent control as often ineffective. Here, by using the example from a pilot case-study in the Bahamas, we present a unique experience wherein, through multidisciplinary and community engagement, we simultaneously developed a standardised national surveillance protocol, and performed two parallel but integrated activities: (1) eight days of theoretical and practical training of selected participants; and (2) a three-month post-training pilot rodent surveillance in the urban community of Over-the-Hill, Nassau, The Bahamas. To account for social and environmental conditions influencing rodent proliferation in the Bahamas, we engaged selected influential community members through a semi-structured interview and gathered additional site-specific information using a modified Centers for Diseases Control and Prevention (CDC) exterior and interior rodent evaluation form, along with other validated instruments such as tracking plates and snap trapping, to test and establish a standardised site-specific rodent surveillance protocol tailored for the Bahamas. Our engagement with community members highlighted poor disposal of animal and human food, irregular garbage collection, unapproved refuse storage, lack of accessible dumpsters, poor bulk waste management, ownership problems and structural deficiencies as major factors fuelling rodent proliferation in the study areas. Accordingly, results from our pilot survey using active rodent signs (that is, the presence of rodent runs, burrows, faecal material or gnawed material) as a proxy of rodent infestation in a generalized linear model confirmed that the variables earlier identified during the community engagement program as significantly correlated with rodent activities (and capturing) across the study areas. The successful implementation of the novel site-specific protocol by trained participants, along with the correlation of their findings with those recorded during the community engagement program, underscores its suitability and applicability in disadvantaged urban settings. This experience should serve as a reference for promoting a standardised protocol for monitoring rodent activities in many disadvantaged urban settings of the Global South, while also fostering a holistic understanding of rodent proliferation. Through this pilot case-study, we advocate for the feasibility of developing sustainable rodent control interventions that are acceptable to both local communities and public authorities, particularly through the involvement of a multidisciplinary team of professionals and community members.

Lessons from a Rodent Surveillance Training: A Standardized Way to Evaluate Rodent Proliferation towards a Sustainable Intervention

Lessons from a Rodent Surveillance Training: A Standardized Way to Evaluate Rodent Proliferation towards a Sustainable Intervention

Lessons from a Rodent Surveillance Training: A Standardized Way to Evaluate Rodent Proliferation towards a Sustainable Intervention

Lessons from a Rodent Surveillance Training: A Standardized Way to Evaluate Rodent Proliferation towards a Sustainable Intervention

Lessons from a Rodent Surveillance Training: A Standardized Way to Evaluate Rodent Proliferation towards a Sustainable Intervention

Lessons from a Rodent Surveillance Training: A Standardized Way to Evaluate Rodent Proliferation towards a Sustainable Intervention

Biological invasions in international seaports: a case study of exotic rodents in Cotonou

Black rat (Rattus rattus), brown rat (Rattus norvegicus), and house mouse (Mus musculus) are known to be among the most common anthropophilic rodent species in cities worldwide. These species are responsible for the destruction of domestic and industrial materials, considerable damage to food stocks as well as zoonotic pathogens circulation and transmission to humans and animals. These invasive species have disseminated in all continents following human-mediated exchanges, especially maritime transports. In particular, seaports appear as privileged rats and mice’s entry points into new regions, thus making them international regulations’ priorities for rodent surveillance and management. Yet, studies on seaport rodents are rare; in particular, investigations on their genetic structure are almost inexistent, thus precluding science-guided interventions. In order to fill such a gap, our study focused on the population genetics of R. rattus, R. norvegicus and M. musculus in the Autonomous Port of Cotonou, Benin. Nine different sites were surveyed for three years. In total, 366 R. rattus, 188 R. norvegicus and 244 M. musculus were genotyped using 18 microsatellites, 16 microsatellites and 17 microsatellites, respectively. Our results show very well-structured genetic clusters in all three species as well as limited impacts of rodent control campaigns. Using comparisons with genotypes from other European, Asian and African countries, we suggest for the first time that settlement of newly introduced individuals may be a rare event. Implications in terms of management units and control and monitoring are discussed.

Vector and rodent surveillance for Orientia tsutsugamushi in north India.

Scrub typhus or chigger borne typhus, caused by Orientia tsutsugamushi is an emerging vector-borne disease as large numbers of cases have been reported in various tropical countries. It is transmitted to humans through bites of infected chiggers (larval mites). The knowledge about the vector, its distribution, density and habitat are important so as to understand the epidemiology of scrub typhus in a given area. To control rickettsial infections, regular rodent-vector surveillance should be planned in areas where the disease transmission is occurring and it will also help to strengthen the existing entomological data related to the vector of scrub typhus in northern India. In the present study, rodent-vector surveillance was planned for one whole year, covering both mite active and non-active seasons (October 2019-December 2020) in selected areas of Chandigarh and Punjab in north India. Rodent tissues and mites were also examined for the presence of O. tsutsugamushi by nested PCR for 56 kDa gene and real-time PCR for 47 kDa outer membrane protein gene. 18S gene PCR was performed for molecular identification of mites. In the surveillance, three types of ectoparasite, viz. mites, fleas and ticks were obtained in rodents. All mites found were of Laelapidae family. None of the pooled rodent tissue samples as well as mite samples were found positive for O. tsutsugamushi by nested PCR for rickettsial DNA. In the present study, we did not get any evidence of carriage of O. tsutsugamushi in either mites or rodents collected and sampled in selected regions in Chandigarh and Punjab. We need to strengthen the entomological surveillance over a broader region and increase the frequency of trapping rodents to increase clarity on vector-reservoir dynamics in this geographical region.

Long-term retrospective observation reveals stabilities and variations of hantavirus infection in Hebei, China

BackgroundHemorrhagic fever with renal syndrome (HFRS) is an emerging zoonotic infectious disease caused by hantaviruses which circulate worldwide. So far, it was still considered as one of serious public health problems in China. The present study aimed to reveal the stabilities and variations of hantavirus infection in Hebei province located in North China through a long-term retrospective observation.MethodsThe epidemiological data of HFRS cases from all 11 cities of Hebei province since 1981 through 2016 were collected and descriptively analyzed. The rodent densities, species compositions and virus-carrying rates of different regions were collected from six separated rodent surveillance points which set up since 2007. The molecular diversity and phylogenetic relationship of hantaviruses circulating among rodents were analyzed based on partial viral glycoprotein gene.ResultsHFRS cases have been reported every year in Hebei province, since the first local case was identified in 1981. The epidemic history can be artificially divided into three phases and a total of 55,507 HFRS cases with 374 deaths were reported during 1981–2016. The gender and occupational factors of susceptible population were invarible throughout, however age of that was gradually aging. The annual outbreak peak always present in spring, while the main epidemic region had gradully altered from south to northeast. Surveillance of rodents revealed that residential rodents significantly possessed higher density and virus-carring rate than field rodents. The house rat, Rattus norvegicus, was the dominant rodent species and Seoul virus S3 sub-genotype which is continued but slightly evolving perhaps to be the sole pathogen for local HFRS cases of Hebei province.ConclusionsThis long-term province-wide surveillance and epidemiological analysis has revealed the stabilities and variations of hantavirus infection in North China. In order to improve current prevention and control strategies of HFRS in China, all surveillance should be continuously enhanced and variations should be paid more attentions.

A Review of Hantavirus Research in Indonesia: Prevalence in Humans and Rodents, and the Discovery of Serang Virus.

Dengue and other common tropical infectious diseases of similar clinical presentation are endemic in Indonesia, which may lead to an underestimation of the prevalence of hantavirus (HTV) infection in the country. To better understand the current burden of HTV infection, this study aimed to both identify acute HTV infection among hospitalized patients with fever and to determine the overall seroprevalence of HTV. These results were further considered within the context of previously reported HTV infection in humans and animals in Indonesia by conducting a review of published literature. As part of an observational cohort study of acute febrile illness, this sub-study retrospectively analyzed blood specimens obtained during admission, during the 2–4-week convalescent period, and three months after admission. Convalescent specimens from patients with clinical signs and symptoms of HTV infection were first screened for HTV IgG. When positive, convalescent specimens and paired acute specimens were screened for HTV IgM, and paired acute specimens were tested for HTV by Reverse Transcription Polymerase Chain Reaction (RT-PCR). A literature review of HTV in Indonesia was conducted on manuscripts manually reviewed for relevance after identification from a search using the terms “hantavirus/Seoul virus” and “Indonesia”. From patients at eight hospitals in seven provincial capitals, HTV IgG seroprevalence was 11.6% (38/327), with the highest being in Denpasar (16.3%, 7/43) and the lowest being in Yogyakarta (3.4%, 1/31). Anti-HTV IgG was most prevalent in adults (13.5%, 33/244) and males (15.6%, 29/186). Acute HTV infections were identified in two subjects, both of whom had Seoul virus. In Indonesia, HTVs have been studied in humans and animals since 1984. Over the past 35 years, the reported seroprevalences in rodents ranged from 0% to 34%, and in humans from 0% to 13%. Fourteen acute infections have been reported, including one in a tourist returning to Germany, but only two have been confirmed by RT-PCR. Almost all rodent and human surveillance results demonstrated serological and molecular evidence of Seoul virus infection. However, in Semarang, anti-Puumala virus IgM has been detected in humans and Puumala RNA in one rodent. In Serang, a new virus named Serang virus was identified due to its differences from Seoul virus. In Maumere, HTV and Leptospira spp. were identified simultaneously in rodents. The burden of HTV infection in Indonesia is underestimated, and additional studies are needed to understand the true prevalence. Seroprevalence data reported here, previous observations of HTV co-infections in rodents, and the prevalence of rodent-borne bacterial infections in Indonesia suggest that the population may be routinely encountering HTVs. While Seoul virus appears to be the most prevalent HTV in the country, further studies are needed to understand which HTVs are circulating.

Seroconversion of 1-year-old Mice to Murine Norovirus.

Rodent sentinel screening for adventitious pathogens is an integral part of many biomedical research institutes and universities that use rodents in research. Typical screening programs involving live sentinel animals typically purchase young SPF sentinel animals that are sampled and replaced quarterly. Previous reports suggest that mice as old as 6 mo are effective sentinels for various agents. In efforts to reduce the number of animals used in our sentinel program, we wanted to investigate the possibility of keeping sentinel animals inhouse for 12 mo at a time. We exposed mice (age, 40 to 48 wk) to murine norovirus (MNV) to test whether they could reliably produce detectable levels of antibodies (similar to younger mice) to this adventitious pathogen. Mice first exposed to MNV at 40 to 48 wk of age seroconverted to MNV after both direct inoculation (through gavage) and indirect exposure (from soiled-bedding transfer) at the same or greater frequency than mice first exposed at 8 to 12 wk of age. These findings indicate that, at least for MNV, sentinel residence time can be extended from 3 to 12 mo without compromising the reliability of seroconversion, thus ultimately reducing sentinel animal numbers. This practice, combined with nonanimal testing modalities (for example, exhaust duct sampling), can increase the sensitivity and specificity of rodent surveillance programs and minimize the use of live animals.

Novel Focus of Sin Nombre Virus in Peromyscus eremicus Mice, Death Valley National Park, California, USA.

The deer mouse (Peromyscus maniculatus) is the primary reservoir for Sin Nombre virus (SNV) in the western United States. Rodent surveillance for hantavirus in Death Valley National Park, California, USA, revealed cactus mice (P. eremicus) as a possible focal reservoir for SNV in this location. We identified SNV antibodies in 40% of cactus mice sampled.

Urban Rodent Surveillance, Climatic Association, and Genomic Characterization of Seoul Virus Collected at U.S. Army Garrison, Seoul, Republic of Korea, 2006-2010.

Rodent-borne pathogens pose a critical public health threat in urban areas. An epidemiological survey of urban rodents was conducted from 2006 to 2010 at the U.S. Army Garrison (USAG), Seoul, Republic of Korea (ROK), to determine the prevalence of Seoul virus (SEOV), a rodent-borne hantavirus. A total of 1,950 rodents were captured at USAG, Yongsan, near/in 19.4% (234/1,206) of the numbered buildings. Annual mean rodent infestation rates were the highest for food service facilities, e.g., the Dragon Hill Lodge complex (38.0 rodents) and the Hartell House (18.8 rodents). The brown rat, Rattus norvegicus, accounted for 99.4% (1,939/1,950) of all the rodents captured in the urban area, whereas only 0.6% (11/1,950) of the rodents was house mice (Mus musculus). In November 2006, higher numbers of rats captured were likely associated with climatic factors, e.g., rainfall and temperatures as rats sought harborage in and around buildings. Only 4.7% (34/718) of the rodents assayed for hantaviruses was serologically positive for SEOV. A total of 8.8% (3/34) R. norvegicus were positive for SEOV RNA by reverse transcription polymerase chain reaction, of which two SEOV strains were completely sequenced and characterized. The 3' and 5' terminal sequences revealed incomplete complementary genomic configuration. Seoul virus strains Rn10-134 and Rn10-145 formed a monophyletic lineage with the prototype SEOV strain 80-39. Seoul virus Medium segment showed the highest evolutionary rates compared with the Large and Small segments. In conclusion, this report provides significant insights into continued rodent-borne disease surveillance programs that identify hantaviruses for analysis of disease risk assessments and development of mitigation strategies.

Norway Rat Sewer Baiting Program in the City of Oakland

Author(s): Why, Adena M.; James, David K; Gay, Robert B. | Abstract: The County Service Area (CSA) 1984-1 for Vector Control was established in June 1984 to serve the public’s needs for providing a comprehensive vector control program throughout Alameda County. In 1987, the City of Oakland recognized that it had a severe rat problem emanating from the sanitary sewers, and in an effort to control them the voters approved a supplemental assessment. For thirty years the CSA has implemented an urban rodent surveillance program focusing on monitoring and controlling commensal rats (Norway and roof rats) and mice in residential, commercial, and business properties. In 2017, the CSA received 2,917 Requests for Service from the public about domestic rodents (2,282 re: rats and 635 re: mice), representing 38.9% of overall service requests. Those 2,917 rodent service requests had staff biologists performing 16,722 field services operations related to rodents. The field service operations included performing smoke and dye tests of sewer lines for breaks; field and residential surveys for rodent activity; recommendations and follow-up evaluations of rodent control measures; and assistance with enforcement actions. In 2017, a total of 8,150 sewer inspections and 1,531 applications of Contrac rodenticide bait were made in the City of Oakland. The CSA is now looking at incorporating rodenticide resistance testing, GIS data analysis, pulse-baiting strategies, and disease surveillance as part of an Integrated Pest Management program as improvements in 2018.

Draft genome of the emerging pathogen, Kocuria marina, isolated from a wild urban rat.

Kocuria marina has recently emerged as a cause for catheter-related bloodstream infections in patients with underlying health complications. One K. marina strain was recently isolated from the lung tissues of a wild urban rat (Rattus rattus diardii) caught during rodent surveillance. Here, we present the draft genome of the first K. marina animal isolate, K. marina TRE150902.

Chigger Mite (Acari: Trombiculidae) Survey of Rodents in Shandong Province, Northern China.

Chigger mites are parasites of rodents and other vertebrates, invertebrates, and other arthropods, and are the only vectors of scrub typhus, in addition to other zoonoses. Therefore, investigating their distribution, diversity, and seasonal abundance is important for public health. Rodent surveillance was conducted at 6 districts in Shandong Province, northern China (114–112°E, 34–38°N), from January to December 2011. Overall, 225/286 (78.7%) rodents captured were infested with chigger mites. A total of 451 chigger mites were identified as belonging to 5 most commonly collected species and 3 genera in 1 family. Leptotrombidium scutellare and Leptotrombidium intermedia were the most commonly collected chigger mites. L. scutellare (66.2%, 36.7%, and 49.0%) was the most frequently collected chigger mite from Apodemus agrarius, Rattus norvegicus, and Microtus fortis, respectively, whereas L. intermedia (61.5% and 63.2%) was the most frequently collected chigger mite from Cricetulus triton and Mus musculus, respectively. This study demonstrated a relatively high prevalence of chigger mites that varied seasonally in Shandong Province, China.

Quality of Plague Surveillance System in Pasuruan Regency Year 2014 Based on Surveillance Attributes

Plague which is the zoonosis quarantine disease remains occur in Pasuruan Regency. Plague suspect was still found until year 2013. Plague surveillance that still actively conducted in Pasuruan Regency is probably the only one plague surveillance in Indonesia. Plague surveillance consist of human and rodent surveillance. Evaluation of surveillance system is needed to improve its quality, efficiency, and usefulness. This research aimed to assess the quality of plague surveillance system in Pasuruan Regency year 2014 based on attributes which are simplicity, flexibility, acceptability, data quality, sensitivity, predictive value positive, representativeness, timeliness, and stability. The research design was evaluation study. Subjecct was plague surveillance system in Pasuruan Regency year 2014. Data were collected by interviews, observations, and document study. The obtained data and information were compared to the guidelines and recent theories then presented in narrations, tables, and figures. The research showed that the surveillance system was simple and flexible, lack of data quality and acceptability, unmeasurable sensitivity and predictive value positive, low representativeness and timeliness, and high stability. This research concluded that quality of plague surveillance system in Pasuruan Regency based on its attributes was not good enough. The suggestion given are conduct training, supply a sufficient budgetary fund, do monitoring and evaluation periodically, disseminate information to another program and sector, also to the community, send surveillance report by e-mail, use spreadsheet software for surveillance rodent reporting, improve the report by including information about damage serum, serum less than the total of captured rodent, and report about the missing trap. Keyword: plague, human surveillance, rodent surveillance, surveillance attributes, evaluation

Quality of Plague Surveillance System in Pasuruan Regency Year 2014 Based on Surveillance Attributes

Plague which is the zoonosis quarantine disease remains occur in Pasuruan Regency. Plague suspect was still found until year 2013. Plague surveillance that still actively conducted in Pasuruan Regency is probably the only one plague surveillance in Indonesia. Plague surveillance consist of human and rodent surveillance. Evaluation of surveillance system is needed to improve its quality, efficiency, and usefulness. This research aimed to assess the quality of plague surveillance system in Pasuruan Regency year 2014 based on attributes which are simplicity, flexibility, acceptability, data quality, sensitivity, predictive value positive, representativeness, timeliness, and stability. The research design was evaluation study. Subjecct was plague surveillance system in Pasuruan Regency year 2014. Data were collected by interviews, observations, and document study. The obtained data and information were compared to the guidelines and recent theories then presented in narrations, tables, and figures. The research showed that the surveillance system was simple and flexible, lack of data quality and acceptability, unmeasurable sensitivity and predictive value positive, low representativeness and timeliness, and high stability. This research concluded that quality of plague surveillance system in Pasuruan Regency based on its attributes was not good enough. The suggestion given are conduct training, supply a sufficient budgetary fund, do monitoring and evaluation periodically, disseminate information to another program and sector, also to the community, send surveillance report by e-mail, use spreadsheet software for surveillance rodent reporting, improve the report by including information about damage serum, serum less than the total of captured rodent, and report about the missing trap. Keyword: plague, human surveillance, rodent surveillance, surveillance attributes, evaluation

Effects of Humidity Variation on the Hantavirus Infection and Hemorrhagic Fever with Renal Syndrome Occurrence in Subtropical China.

Infection rates of rodents have a significant influence on the transmission of hemorrhagic fever with renal syndrome (HFRS). In this study, four cities and two counties with high HFRS incidence in eastern Hunan Province in China were studied, and surveillance data of rodents, as well as HFRS cases and related environmental variables from 2007 to 2010, were collected. Results indicate that the distribution and infection rates of rodents are closely associated with environmental conditions. Hantavirus infections in rodents were positively correlated with temperature vegetation dryness index and negatively correlated with elevation. The predictive risk maps based on multivariate regression model revealed that the annual variation of infection risks is small, whereas monthly variation is large and corresponded well to the seasonal variation of human HFRS incidence. The identification of risk factors and risk prediction provides decision support for rodent surveillance and the prevention and control of HFRS.