Control of Common Vole (Microtus arvalis) in Alfalfa Crops Using Reduced Content of Anticoagulants

The common vole, Microtus arvalis, which is prone to cyclic overpopulation, poses a significant threat to sustainable alfalfa production by either chewing shoots periodically or gnawing and damaging roots permanently. In areas with established vole colonies, the density of alfalfa plants was shown to decrease 55.3–63.4%. Simultaneously, the number of alfalfa shoots decreased by 60.9–71.7%. These experiments were conducted in compliance with an EPPO standard method in alfalfa fields at three geographically remote sites. The experiment tested the efficacy of the most widely used acute rodenticide zinc phosphide (2%), and anticoagulants applied at significantly reduced doses of active ingredients, i.e., bromadiolone (25 ppm) and brodifacoum (25 ppm), as well as a combination of these active ingredients at a low concentration (10 + 10 ppm). Three weeks after treatment, zinc phosphide and brodifacoum achieved the highest average efficacy, at 98.5% and 92.05%, respectively, while the average efficacy of the anticoagulant combination and bromadiolone was 87.2% and 75.5%, respectively. The achieved efficacy of baits based on brodifacoum and the combination of brodifacoum and bromadiolone in controlling common voles indicates their possible utilization in the field. Baits with 25 ppm of brodifacoum and the combination of bromadiolone and brodifacoum (10 + 10 ppm) showed satisfactory results and their introduction could significantly improve pest management programs for rodent control. At the same time, the use of anticoagulant rodenticides with reduced contents of active ingredients would significantly reduce their exposure to non-target animals, especially predators and vultures. By further improving the palatability of tested baits for target rodent species, their efficacy and safety of application would be significantly improved.

Investigation of methods of rodent control and analysis of existing devices constructed based on electrophysical control method

This article is considered used and newly developed rodent control devices, taking into account operating experience with patented structures, and analyzes the options for their use to control the pests. The analysis of the currently used methods for protection showed that there is a need not only to use devices for scaring and destruction, but also to design a device for research is required taking electrophysical methods for consideration. As a result, a model of an electrocontact grid has been proposed that plays the role of a stun gun to scare off rodents. Keywords: DERATIZATION, DERATIZER, ULTRASOUND, RODENTS, METHODS OF CONTROL, STUN GUN

Effectiveness of snap traps on capturing rodent and small mammals in rural area of two provinces (Yogyakarta and West Java) in Indonesia

The study was conducted to determine the effectiveness of snap traps on capturing the rodents and small mammals in two provinces (Yogyakarta and West Java). A small rural area surrounded by large scale ricecrops which indicate rodent damage seasonally was selected as the study site. The trappings were executed during the period of November 2018 – August 2020. Consecutive trappings were performed in two regions using snap traps baited with fresh salty fish and roasted coconut. Around 40-65 traps were set in West Java study sites and 60-65 traps in Yogyakarta for every single trap night, respectively. We checked the captured animals in the early morning and collected them for identification and sexing. In the late afternoon we continued with cleaning of the traps and put in the new same type of bait. A total of 517 animals were obtained with the proportion of the two sexes was almost the same (45.45% males:54.40% females). Based on the physical characteristics, those captured animals were three rodent species (Rattus argentiventer, Rattus tanezumi, Bandicota indica) and one species of insectivore (Suncus murinus). Regarding trapping rate of success, Yogyakarta denoted average values (21.38% in the first trapping and 26.04% from the second trapping) compared to West Java which was only accounted for half of them (11.31% and 11.24% from the first and second trapping, respectively). The heterogeneous habitat configuration probably allowed this situation to occur in Yogyakarta. Moreover, rodent control activities in West Java were implemented more intensively compared to Yogyakarta.

Occurrence of Multi-Drug-Resistant Escherichia coli in Chickens, Humans, Rodents and Household Soil in Karatu, Northern Tanzania

We investigated antibiotic resistance profiles of Escherichia coli among 960 samples obtained from chickens (236), humans (243), rodents (101) and soil (290). E. coli was isolated from 650 (67.7%) samples. Isolation frequency varied significantly between chickens, humans, rodents and soil samples, being 81.6%, 86.5%, 79.2% and 31.0%, respectively (p < 0.001). Resistance rates were particularly higher against imipenem (79.8%), cefotaxime (79.7%) and tetracycline (73.7%) and moderate against amoxicillin-clavulanate (49.4%). Overall, 78.8% of the isolates were multidrug-resistant (MDR) among which, 38.8%, 25.1%, 12.9% and 2.5% exhibited resistance to three, four, five and six different classes of antibiotics, respectively. Multidrug-resistant E. coli were observed in 27.7%, 30.3%, 10.8% and 10.0% of the isolates from chickens, humans, rodents and soil samples, respectively. Our results show high levels of antimicrobial resistance including MDR in E. coli isolated from chickens, humans, rodents and soil samples in Karatu, Northern Tanzania. Comprehensive interventions using a one-health approach are needed and should include improving (i) awareness of the community on judicious use of antimicrobial agents in humans and animals, (ii) house conditions and waste management and (iii) rodent control measures.

Effectiveness and costs of interventions to reduce the within-farm Toxoplasma gondii seroprevalence on pig farms in the Netherlands

Background The parasite Toxoplasma gondii (T. gondii) is recognized as one of the major foodborne pathogens with a high human disease burden. To control T. gondii infections in pigs, European Food Safety Agency (EFSA) advises serological testing of pigs and audits of pig farms to identify risk factors for T. gondii infection. In line with this approach, the aim of the current study was to assess the effectiveness and costs of intervention measures implemented to reduce the T. gondii seroprevalence on finishing pig farms in the Netherlands. A crossover clinical trial was conducted at five case farms were their own control and the cross-over moment was the implementation of interventions to reduce risk factors. Each of the case farms had a farm-specific intervention strategy with one principal intervention measure (neutering of cats, professional rodent control or covering food storage). Results All finishing pig farms (n = 5) showed a reduction in T. gondii seroprevalence within one year of implementing the intervention strategy. Cat neutering (n = 3) and feed coverage (n = 1) showed statistically significant reductions in seroprevalence. Rodent control (n = 1) did not show a statistically significant reduction. The estimated reduction in seroprevalence in response to the neutering of cats and feed coverage were 67 and 96 %, respectively. Conclusions Our work demonstrates that it is possible to reduce the within-farm T. gondii seroprevalence within one year after interventions were implemented to reduce T. gondii risk factors. This information is essential and encouraging for policy makers, food business operators, and farmers to implement in their risk assessment and to apply to food safety control systems.

Single Nucleotide Polymorphisms (SNPs) Within Vkorc1 in Rodent Populations in a Tropical City-state: Implications for Anticoagulant Rodenticide Use for Rodent Control

Anticoagulant rodenticides are commonly used in rodent control because they are economical and have great deployment versatility. However, rodents with Single Nucleotide Polymorphism (SNP) mutations within the Vkorc1 gene are resistant to the effects of anticoagulant rodenticide use and this influences the effectiveness of control strategies that rely on such rodenticides. This study examined the prevalence of rat SNP mutations in Singapore to inform the effectiveness of anticoagulant rodenticide use. A total of 130 rat tail samples, comprising 83 Rattus norvegicus (63.8%) and 47 Rattus rattus spp. (36.2%) were conveniently sampled from November 2016 to December 2019 from urban settings and sequenced at exon 3 of Vkorc1. Sequencing analysis revealed 4 synonymous and 1 non-synonymous mutations in Rattus rattus spp. samples. A novel synonymous mutation of L108L was identified and not previously reported in other studies. Non-synonymous SNPs were not detected in the notable codons of 120, 128 and 139 in Norway rats, where these regions are internationally recognised to be associated with resistance from prior studies. Our findings suggest that the prevalence of anticoagulant rodenticide resistance in Singapore is low. Continued monitoring of rodenticide resistance is important for informing rodent control strategies aimed at reducing rodent-borne disease transmission.

Assessment of Biosecurity in Confined Pig Farms in Urban and Peri-Urban Areas of Abidjan (Ivory Coast)

The purpose of this study is to assess the status of biosecurity measures in confined pig farms in the urban and peri-urban areas of Abidjan in order to make recommendations for improving their sanitary conditions. This study was conducted in 76 confined pig farms in order to assess biosecurity practices. It consisted of administering a questionnaire to farmers in the urban and peri-urban areas of Abidjan. The analysis of the implementation of external biosecurity measures showed that 46.67% of the farms were not fenced, 85.20% were adjacent to other pig farms and the distance between them was less than 200m in 75.40% of cases. Similarly, 35.80% of the farms were located less than 100m from houses. Barriers to entry existed in 37.5% but only 2.8% and 8.82% of farms had signs for visitors and trucks and a vehicle disinfection device at the entrance respectively. Only 6.8% of the farms had foot baths at the entrance of the buildings. The vast majority of farmers stated that they quarantine new animals. The principles of internal biosecurity are very little respected. Workers wear work clothes on the majority of farms, but more than half of them go outside with them. The same working equipment is used in the different lodges without distinction of the age of the subjects and very little cleaned and disinfected. The disinfectants used are bleach and cresyl without any dilution standard. The presence of other animal species was noted and rodent control was not practised. The pathologies encountered are predominantly diarrhoea, and postweaning animals are the most affected.

“I don’t feel safe sitting in my own yard”: Chicago resident experiences with urban rats during a COVID-19 stay-at-home order

Background Encounters with rats in urban areas increase risk of human exposure to rat-associated zoonotic pathogens and act as a stressor associated with psychological distress. The frequency and nature of human-rat encounters may be altered by social distancing policies to mitigate the COVID-19 pandemic. For example, restaurant closures may reduce food availability for rats and promote rat activity in nearby residential areas, thus increasing public health risks during a period of public health crisis. In this study, we aimed to identify factors associated with increased perceived exposure to rats during a stay-at-home order, describe residents’ encounters with rats relevant to their health and well-being, and identify factors associated with increased use of rodent control. Methods Urban residents in Chicago, a large city with growing concerns about rats and health disparities, completed an online questionnaire including fixed response and open-ended questions during the spring 2020 stay-at-home order. Analyses included ordinal multivariate regression, spatial analysis, and thematic analysis for open-ended responses. Results Overall, 21% of respondents (n = 835) reported an increase in rat sightings around their homes during the stay-at-home order and increased rat sightings was positively associated with proximity to restaurants, low-rise apartment buildings, and rat feces in the home (p ≤ 0.01). Many respondents described feeling unsafe using their patio or yard, and afraid of rats entering their home or spreading disease. Greater engagement with rodent control was associated with property ownership, information about rat control, and areas with lower incomes (p ≤ 0.01). Conclusions More frequent rat encounters may be an unanticipated public health concern during periods of social distancing, especially in restaurant-dense areas or in low-rise apartment buildings. Rat presence may also limit residents’ ability to enjoy nearby outdoor spaces, which otherwise might buffer stress experienced during a stay-at-home order. Proactive rat control may be needed to mitigate rat-associated health risks during future stay-at-home orders.