Rat Infestation Research Articles

TomFi: Small Object Tracking Using Commodity WiFi

Rodent infestation has always been one of the most severe threats to humans, which to solve consumes massive manpower and resources. People usually use traps or poisons to treat rat infestation. Such passive countermeasures are inefficient. Damage often occurs when the rats are finally trapped or killed, not to mention the potential risk to injure humans or cause pollution. In this article, we propose a WiFi-based active small object tracking system named TomFi . The core components of TomFi include several deep learning techniques that bridge rat locations/motions and WiFi signal variations (represented by the channel state information). TomFi first employs a detection model to detect the appearance of the rat and then localize it based on a two-branch localization model. Through the design of the two-branch localization model, to our best knowledge, we are the first to solve the information loss and distortion problem. We conducted extensive experiments in both the laboratory environment and real-world kitchen scenarios. The results show that TomFi can achieve a detection success rate of 99%+ and a centimeter-level localization accuracy in real time.

Growing crisis of urban rat infestation in Karaj city, Iran: Insights from hotspot mapping and social network analysis

To control the increasing growth of rat populations in metropolitan areas, several factors need to be considered to mitigate the risks posed by rats. Identifying rat density hotspots with more efficient methods and assessing people's experiences and attitudes toward them can be useful in prioritizing rat control efforts. We focused on the two most common species of rats (Rattus rattus and Rattus norvegicus) in the metropolis of Karaj, the fourth most populous and the largest immigrant-friendly city in Iran. The urban rat infestation is one of the problems caused by the high population growth in Karaj and the insufficient development of urban infrastructure and waste collection. It has led to discontent and public concern about rat infestations and there is a need to address the associated threats. We applied the Kernel Density Function and Optimized Hotspot Analysis to the presence points of the aforementioned types of rats and found that while Optimized Hotspot projects a macro view of hotspots at the city level, the Kernel Density Function prioritizes neighborhoods for initial actions. In addition, social network analysis with complementary regression models was conducted to determine people's experiences. The results show that fear of rats and concern about their presence form the basis of people's attitudes toward rats and lead to feelings of hatred. Moreover, economic harm reinforces people's motivation to control or eliminate this species. Despite their unpleasant feelings toward rats, people have a great influence on the growth of rat infestations by creating food sources through improper waste disposal. They prefer to use traps and poison instead of disposing of household waste and following the principles of cleanliness as preventive measures and believe that the lack of proper garbage collection by the municipality is the most important reason for the growth of rat populations. They are not sufficiently aware of their position in addressing this crisis. Our findings argue for the formation of a stronger network between the relevant authorities and residents, especially those living in the hotspots, to educate them about their role in rat control and to gain their cooperation in improving the city's waste management system.

Associations between Rat Infestations and Mental Health Vary by Gender, Race, and Income in Chicago.

Rats are an understudied stressor for people in urban environments around the world but the effects may not be distributed equally among residents. In this study, we examined associations between residential rat sightings and mental health in Chicago, where rat complaints are the highest of any American city. We examined how this relationship varied by frequency of rat sightings, race, ethnicity, income, home ownership, and gender and explored potential psychosocial pathways (e.g., feelings about the home) between rat sightings and mental distress. We conducted a randomized household survey along an income gradient in 2021 and asked about depressive symptoms in the past week (i.e., Center for Epidemiologic Studies Depression scale), frequency of rat sightings in/around the home, perceptions of rats, neighborhood conditions, and socio-demographic characteristics. We used logistic regression to assess relationships among these variables for our entire sample and for specific demographics using stratified models. Respondents (n = 589; 409 complete cases) who saw rats in/around the home daily/almost daily had 5.5 times higher odds of reporting high depressive symptoms relative to respondents who saw rats less frequently after accounting for socio-demographics and neighborhood conditions. This relationship was significant for men and respondents with lower incomes or race or ethnicity other than white. Our results show that rat infestations should be considered a threat to mental health among urban residents. Increased mental health support for residents living in rat-infested housing may improve public health in cities.

A Bayesian Spatial Model to Correct Under-Reporting in Urban Crowdsourcing

Decision-makers often observe the occurrence of events through a reporting process. City governments, for example, rely on resident reports to find and then resolve urban infrastructural problems such as fallen street trees, flooded basements, or rat infestations. Without additional assumptions, there is no way to distinguish events that occur but are not reported from events that truly did not occur--a fundamental problem in settings with positive-unlabeled data. Because disparities in reporting rates correlate with resident demographics, addressing incidents only on the basis of reports leads to systematic neglect in neighborhoods that are less likely to report events. We show how to overcome this challenge by leveraging the fact that events are spatially correlated. Our framework uses a Bayesian spatial latent variable model to infer event occurrence probabilities and applies it to storm-induced flooding reports in New York City, further pooling results across multiple storms. We show that a model accounting for under-reporting and spatial correlation predicts future reports more accurately than other models, and further induces a more equitable set of inspections: its allocations better reflect the population and provide equitable service to non-white, less traditionally educated, and lower-income residents. This finding reflects heterogeneous reporting behavior learned by the model: reporting rates are higher in Census tracts with higher populations, proportions of white residents, and proportions of owner-occupied households. Our work lays the groundwork for more equitable proactive government services, even with disparate reporting behavior.

Tyto alba Cultivation in Balinese Cultural Perspective

Rat infestation (Rattus argentiventer) in Subak Pagi and Subak Bengkel, Tabanan regency, Bali has resulted in rice crop failure in both areas. Rice production decreased drastically to only about 10 - 20% of normal conditions. The utilization of Tyto alba as a biological control of rat pests, turns out to be able to play a very effective role in controlling pest attacks. In nature, Tyto alba population continues to decline due to hunting and agricultural land clearing. This research aims to study the cultivation of Tyto alba, especially from a cross-generational cultural perspective. Generations are grouped by year of birth with a range of 20 years, from 1960 - now, into generations X, Y and Z, respectively. The research used descriptive qualitative method, through depth interview approach and forced field analysis. The results showed that there are four supporting factors for the cultivation of Tyto alba as a rat pest control, namely first Tyto alba is very effective in controlling rat pests. Another supporting factor is that Tyto alba has actually been known for a long time by the people in the two subak and has a belief value system in the life of the subak community, as well as environmentally friendly and able to maintain the food chain. There are four inhibiting factors in Tyto alba conservation efforts, namely, the lack of committed breeding officers, availability and management of food, land for preservation and development and very limited financial support. Analysis forced field concludes that, cross-generational public perception in the acceptance of Tyto alba as a biological control of rat pests is very positive. However, preservation efforts with a breeding system cannot be done in both subak at this time. Efforts to preserve and develop Tyto alba are carried out by releasing it in nature with conservation protection through village regulations.

Rat composition and population in mature oil palm adjacent to paddy field

Rat is one of the main pests in an oil palm plantation, impacted at various types and stages of oil palm growth. Ungkaya estate has a historical & endemic infestation of rats, especially in several fields adjacent to paddy fields. This study aimed to find out the seasonal migration of rats from paddy fields to oil palm fields in Ungkaya Estate. Five plots were used for trapping, identifying rat species, monitoring of rat population, rat damage intensity, and rat habitat preference at each stage of the paddy season. Trapped rats were identified as Rattus tiomanicus (56.91%), Rattus argentiventer (36.17%), and Rattus tanezumi (6.91%). The intensity of rat damage to the palm was high during the vegetative phase of paddy season and the full moon phase. The regression analysis results showed that the number of trapped rats has a positive relationship to rat damage intensity for the vegetative and harvesting stage at full moon. The number of trapped R. argentiventer at vegetative stage was higher than the generative & harvesting phase of the paddy season. Moreover, there were rat footprints observed on the riverside leading to the oil palm field. The results of all observation parameters concluded that there was seasonal migration of rats between the oil palm fields and the paddy fields in Ungkaya estate. The information is pivotal in drawing up suitable mitigation measures to control and minimize rat damage to the oil palm.

Demystifying re-emergence zoonotic threat: A 5-year epidemiology of leptospirosis in Negeri Sembilan, Malaysia

IntroductionLeptospirosis is a re-emergence of zoonotic disease with significant morbidity and mortality. As a tropical country, there is a concerning trend of leptospirosis infection in Malaysia. However, the epidemiological study of the infection remains scarce and does not reflect the current information. Therefore, the study aimed to describe its epidemiology within the last 5-year in the state of Negeri Sembilan. MethodsA cross-sectional study was done using dataset from national electronic surveillance registry from year 2018–2022. Descriptive statistics method was applied to build the epidemiological narrative of leptospirosis infection. All data was kept confidential and abide to Helsinki declaration. ResultsA total of 1290 cases of leptospirosis was registered and included in the analysis. Majority of the cases were from adults’ group (68.4 %), male (68.4 %), of Malay ethnicity (69.8 %), unemployed (56.7 %), and from rural area (54.4 %). The possible risk exposure was from rat infestation (15.1 %), water-based activity (12.5 %), and contact with contaminated soil (7.7 %). The proportion of cases registered in the densely populated areas were comparable among those who are employed and unemployed There were overall 21 (1.6 %) mortality cases from the data. ConclusionLeptospirosis is a public health threat and need to be approached holistically. Awareness of the disease need to be continuously advocated to the public as well as to the healthcare providers. Strengthening the surveillance system at the local and national level is important as it can act as an early warning system to prevent outbreak to happen.

Simplified sewerage to prevent urban leptospirosis transmission: a cluster non-randomised controlled trial protocol in disadvantaged urban communities of Salvador, Brazil

IntroductionLeptospirosis is a globally distributed zoonotic and environmentally mediated disease that has emerged as a major health problem in urban slums in developing countries. Its aetiological agent is bacteria of...

Twin Research and Human Genetics - News, Views & Comments: Memoirs and Autobiographies by Twins: Research Angles and Human Interest/Twin Research Reviews: Fetal Reduction in Twin Pregnancy; Twins' Personality and Military Service; Growth Restriction in Twins; Advances in Conjoined Twin Separation/Media Reports: Update on Scientist Who Performed Gene Editing on Twins; Twins From 33-Year-Old Embryos; Twins' Outcomes From Dietary Differences;

Twins' memoirs and autobiographies both enlighten and entertain. These works, often overlooked by researchers, may suggest new avenues for investigation, such as nonshared environmental events that propel twins in different directions. Of course, MZ twins' generally parallel experiences and DZ twins generally criss-crossing paths are the bases of fascinating life stories. The following sections examined recent research on fetal reduction in twin pregnancy, twins' personality and military service, growth restriction in twins, and advances in conjoined twin separation. This article closes with reports of a scientist who performed gene editing on twins, a twin conception from 33-year-old embryos, twins' physical outcomes from dietary differences, fraternal twins with the world's largest height difference and the Twin Home Experts who conquer rat infestation in New York.

The Indoors/Outdoors Divide: Homelessness, Rat Infestation, and Spatial Management in Downtown Los Angeles

In 2019, Los Angeles, California's City Hall was reported to be infested with rats. LA's pest control contractor later drew a link between this rat problem and nearby encampments of unhoused residents. I use these connected cases of homelessness and rat control in Los Angeles to investigate the spatial and symbolic logics that guide urban social processes. Using computational and qualitative text analysis, interviews, and participant observation, I argue that rats and homelessness are issues tied to the proper place of nature in cities. While urban nature is central to the aspirational goals of urbanization, where institutions craft a desirable, recognizably urban life, I argue that managing it means not just introducing “good” nature (parks, street trees, etc.) to cities, but also keeping “bad” nature at bay. Practically, this entails guarding public faith in the boundary between “indoors” and “outdoors.” Homelessness and rat infestations present challenges to this goal because they represent inverse spatial transgressions of the indoors/outdoors divide. Rats bring the outdoors inside, compromising safety and security. Homeless encampments, meanwhile, represent domestic, indoor life spilling over into the outdoors. City institutions materially maintain the indoors/outdoors divide and symbolically attend to it by removing meaningful indications of these spatial transgressions.

The stop-feed effect of cholecalciferol (vitamin D3) and the efficacy of brodifacoum combined with cholecalciferol in Y139C-resistant Norway rats (Rattus norvegicus)

Second-generation anticoagulant rodenticides potentially build persistent residues in animals and accordingly pose a risk of secondary poisoning. We examined the effect of a low concentration of cholecalciferol in brodifacoum bait on bait consumption by Norway rats (Rattus norvegicus Berkenhout 1769) and on the control success in a laboratory study and in field trials. Additionally, the efficacy of both baits was determined against resistant Y139C rats. Cholecalciferol caused a strong stop-feed effect after two days in the laboratory study. On two field study sites each, bait containing either 25 mg kg−1 brodifacoum or 25 mg kg−1 brodifacoum and 100 mg kg−1 cholecalciferol was applied to treat infestations of Norway rats. Infestations were assessed pre- and post-treatment. Rats were radio-tagged, and carcasses were searched for during the treatment period. DNA of each rat was genotyped to determine the resistance status conferred by the VKORC1 gene. On all farms, control success exceeded 90%. On farms treated with brodifacoum only, the ratio of total bait consumption to pre-treatment census was significantly higher (6.6 and 4.8 times) than on farms treated with the combination (2.7 and 2.9 times). 78.8% of 183 rats were confirmed Y139C resistant. Bait ingestion was reduced by almost fifty per-cent when cholecalciferol was added to the bait with no impact on control success. All treatments resulted in control levels exceeding 90%, despite a high proportion of anticoagulant-resistant rats. When the use of highly toxic compounds is required in resistance management, addition of cholecalciferol to these baits may reduce the transfer of residues to the environment.

Serological Surveillance of Zoonotic Pathogens in Rats in Markets in Bogor, Indonesia.

<b><i>Background:</i></b> Rats are a major carrier of several pathogens, including zoonotic pathogens that can cause fatal diseases in humans. Indonesia has one of the fastest growing populations, with high infestation of rats in urban areas. Therefore, this study aims to assess the seropositivity of zoonotic pathogens in rats from four markets in Bogor, Indonesia. <b><i>Materials and Methods:</i></b> A total of 80 brown rats (<i>Rattus norvegicus</i>) were captured from the markets and screened for the presence of some zoonotic pathogens, specifically hantavirus, <i>Leptospira</i> spp., <i>Orientia tsutsugamushi</i>, tick-borne encephalitis virus (TBEV), and lymphocytic choriomeningitis virus (LCMV) antibodies, using indirect fluorescence assay or enzyme-linked immunosorbent assay. <b><i>Results:</i></b> Among the 80 rats, 40% were seropositive for hantavirus, 36.3% for <i>Leptospira</i> spp., 11.3% for <i>O. tsutsugamushi</i>, 6.3% for TBEV, and 0% for LCMV. <b><i>Conclusion:</i></b> Overall, these results indicate that rats in Bogor pose a potential zoonotic risk to humans.

Determinants of diarrhoeal disease in children living in low-income households in a periurban community in Cape Town, South Africa

Background. Water, sanitation and hygiene are critically important in reducing morbidity and mortality from childhood diarrhoeal disease and malnutrition in low-income settings.Objectives. To assess the association of diarrhoeal disease with factors relating to domestic hygiene, the environment, sociodemographic status and anthropometry in children &lt;2 years of age.Methods. This was a case-control study conducted in a periurban community 35 km from the centre of Cape Town, South Africa. The study included 100 children with diarrhoeal disease and 100 age-matched controls without diarrhoea, who were recruited at primary healthcare clinics. Sociodemographic status, environmental factors and domestic hygiene were assessed using a structured questionnaire; anthropometry was assessed using the World Health Organization’s child growth standards. Univariate and multivariate logistic regression analyses were performed to identify the factors associated with diarrhoea. Results. The results of the univariate logistic regression showed significant susceptibility to diarrhoea in study cases compared with controls when the caregiver was ≥25 years old (odds ratio (OR) 1.82; 95% confidence interval (CI) 1.02 - 3.23; p=0.042); when children were in day care or cared for by a family member or a relative than when cared for by their mother (OR 1.97; 95% CI 1.06 - 3.65; p=0.032); and when the mothers were employed rather than at home (OR 2.23; 95% CI 1.21 - 4.12; p=0.01). Multivariate logistic regression analysis was used to identify predictors of diarrhoea, which entailed relaxing the inclusion criteria for the univariate analysis variables (p&lt;0.25). The predictors significantly associated with diarrhoea were household problems relating to rat infestation (OR 2.44; 95% CI 1.13 - 5.28; p=0.027); maternal employment (OR 2.47; 95% CI 1.28 - 4.76; p=0.007); and children in day care or cared for by a relative (OR 2.34; 95% CI 1.21 - 4.54; p=0.01). Significantly more of the mothers who were employed than those who were unemployed had children in day care or cared for by a relative.Conclusion. Practices relating to employment, childcare and the domestic environment were significant predictors of diarrhoea. Effective policy implementation on water, sanitation and domestic hygiene could prevent diarrhoeal disease and reduce its impact on children’s growth, especially during the annual diarrhoeal surge season in this and similar periurban communities.

Reconsidering the “War on Rats”: What We Know From Over a Century of Research Into Municipal Rat Management

To sustainably control urban rat infestations, management efforts need to encompass large areas of urban centers. Therefore, the objective of this review and narrative synthesis was to collate what is known about municipal-scale rat management. We explored the management frameworks that have been used at a large scale in cities and we describe the expectations of experts who have designed and implemented these frameworks. We found that there has been a persistent “war on rats” paradigm driving this literature since the early 1900s. Not only was there little quantitative evidence to support this paradigm and associated methodologies, but together, they failed to meet the expectations of those who designed and implemented them due to real-world constraints (i.e., limited resources). To improve the field of municipal management, we identify two distinct options. First, stakeholders may continue to wage the “war on rats” while improving existing strategies within this paradigm. Key pathways forward include developing evaluation metrics aligned with program objectives, establishing the cost-effectiveness of methodologies, and improving control efficacy. Second, we suggest a new paradigm, one that considers that rat management is a complex system that must be approached by first mapping its complexity to highlight and prioritize the many complex upstream determinants of infestations. This perspective highlights how rat management may be a wicked problem for which there is no overarching solution and instead can only be managed by making incremental gains in individual components of the problem over time. Importantly, we propose an alternative management objective that places a priority on improving the overall health of the community, instead of on eliminating rats, and we stress that management goals must address stakeholders’ goals as their investment is essential for a sustained program.

The effect of habitat condition of oil palm (Elaeis guineensis Jacq.) to arthropods and rat infestation

The research was conducted to evaluate the effect of oil palm (Elaeis guineensis Jacq.) plantation types on the diversity and abundance of arthropods, the population and percentage of rat infestation. The research was conducted at oil palm plantation in Cikasungka, Bogor Regency, West Java in 2015 with three different types of plantations i.e. clean cultivation, natural vegetation, and legume cover crop. This research used three sampling methods i.e. pitfall trap, swing net, direct observation. The research was carried out in an area of 100 m x 100 m with 20 sample plants for each habitat. Sampling technique, trapping, and observation of arthropods and rat infestation were done nine times with an interval of two weeks. The results indicated that legume cover crop habitat had the highest arthropods diversity index and the lowest rate of rat infestation, compared with those of the other habitat types of plantations.

Anaphylactic Reactions Due to Triatoma protracta (Hemiptera, Reduviidae, Triatominae) and Invasion into a Home in Northern California, USA.

Simple SummaryKissing bugs are bloodsucking insects found throughout the Western Hemisphere, including the United States, but also within certain regions of the Western Pacific, India, the Middle East, and Africa. Within the Americas, these insects are known to harbor a parasite known as Trypanosoma cruzi, the causative agent of an infection in humans and other mammals known as Chagas disease. The infection can be spread through the fecal matter of the kissing bug when exposed to the skin or ingested from contaminated food or drink products. Kissing bugs will invade human homes and bite residents and their pets. The bite from a kissing bug can also lead to serious allergic reactions, including anaphylaxis. A potentially life-threatening allergic response typically needs emergency medical attention. We describe a home that was invaded by kissing bugs in northern California where the resident developed serious allergic reactions to the bite. The kissing bugs were identified and a blood meal investigation found the presence of human blood as well as the parasite, Trypanosoma cruzi. The resident was tested extensively for chronic Chagas disease due to his repeated exposure to the kissing bug but was found to not have the disease. Those who live in regions where kissing bugs are found naturally should be aware that their bites can be highly allergenic.Background: Triatoma protracta is a triatomine found naturally throughout many regions of California and has been shown to invade human dwellings and bite residents. A man living in Mendocino County, California, reported developing anaphylactic reactions due to the bite of an “unusual bug”, which he had found in his home for several years. Methods: We conducted environmental, entomological, and clinical investigations to examine the risk for kissing bug invasion, presence of Trypanosoma cruzi, and concerns for Chagas disease at this human dwelling with triatomine invasion. Results: Home assessment revealed several risk factors for triatomine invasion, which includes pack rat infestation, above-ground wooden plank floor without a concrete foundation, canine living in the home, and lack of residual insecticide use. Triatomines were all identified as Triatoma protracta. Midgut molecular analysis of the collected triatomines revealed the detection of T. cruzi discrete typing unit I among one of the kissing bugs. Blood meal PCR-based analysis showed these triatomines had bitten humans, canine and unidentified snake species. The patient was tested for chronic Chagas disease utilizing rapid diagnostic testing and laboratory serological testing, and all were negative. Conclusions: Triatoma protracta is known to invade human dwellings in the western portions of the United States. This is the first report of T. cruzi-infected triatomines invading homes in Mendocino County, California. Triatoma protracta is a known vector responsible for autochthonous Chagas disease within the United States, and their bites can also trigger serious systemic allergic reactions, such as anaphylaxis.

Rat Infestation in Gauteng Province: Lived Experiences of Kathlehong Township Residents.

Background: Rat infestation is a major public health issue globally, and particularly in poor urban communities in South Africa. Rats pose significant threats to residents in the form of disease spread and sustained physical injuries. The dearth of knowledge about the experiences of affected residents may curtail the initiation of rat control programs. This study aimed to explore the lived experiences of rat infestation among residents of Katlehong Township in Gauteng Province. Methods: This was a qualitative research study where data were gathered from selected community participants from Katlehong Township in Gauteng Province. A semi-structured interview guide was used to collect data through in-depth interviews. The interviews were digitally recorded and transcribed verbatim, and thematic data analysis was conducted using NVivo12 data processing software. The data were presented in themes and quotations that reflect the views of the participants. Results: Exactly 20 community members aged between 18 and 56 years participated in the study, 80% being females. Over half of the participants were unemployed (60%), inclusive of students. Majority of the participants were either Zulu or Xhosa speakers. Several themes emerged from the data, which included the residents’ experiences of rat infestation, troublesome rats, dirty rats, reasons for rat infestation, and sustained physical injuries. Participants intimated that waste in the environment and overcrowding in homes contributed to rodent infestation. Conclusion: Rat infestation remains a problem that causes severe distress among the residents of Katlehong Township. The experiences reported varied from psychological trauma to bite injuries and destruction of household property. Effective rodent control strategies need to be put in place to manage both the physical and mental risks posed by rat infestation in socially underprivileged communities.

Social distancing measures differentially affected rats in North America and Tokyo.

Because rats are commensal organisms that depend on human activities for food, shifts in human behavior will have pronounced effects on local rat populations. In the spring of 2020, social distancing measures were implemented globally to curtail the spread of SARS-CoV-2. This presented a unique opportunity to obtain information regarding the immediate effects of shifts in human behavior on rat populations in a variety of countries. In response to increased sightings of rats in the USA that were reported in American media, we analyzed the changes in the number of public service calls in Tokyo, Japan. We found that the number of calls increased after the implementation of social distancing measures, suggesting that rat sightings had also increased in Tokyo. We then surveyed the changes in the business activities of pest management professionals in the USA, Canada, and Tokyo. We found that the activities were increased in 50 to 60% of the respondents from the USA and Canada. In contrast, 60 to 70% of the respondents from Tokyo answered that their activities were not changed. These results implied that, following the implementation of social distancing measures, rat infestations increased in North America, but not in Tokyo. The survey also suggested that roof rats were considered to be the predominant rodent species in Tokyo. This may account for the limited infestations in Tokyo because roof rats are more sedentary than brown rats. Taken together, our findings suggest that social distancing measures differentially affected rat populations in North America and Tokyo.Supplementary InformationThe online version contains supplementary material available at 10.1007/s10340-021-01405-z.

APPLICATION METHODS OF COUMATETRALYL BAITS TO CONTROL RATTUS RATTUS DIARDII IN HIGH INFESTATION AREAS

The most widely practiced method of rat control in oil palm plantations is by baiting with anticoagulant rat poisons. Two experiments were conducted to study the efficacy and susceptibility of first-generation anticoagulant rat bait, coumatetralyl (0.375%) to control Rattus rattus diardii. In the first experiment, a laboratory trial was conducted to test two commercial coumatetralyl 0.375 per cent rat baits (5 g and 6 g) and one brodifacoum bait (5 g) in comparison with an untreated control. All the three baits provided excellent kill of Rattus rattus diardii. The results indicated that, Rattus rattus diardii from the locality of Sampit in Central Kalimantan was susceptible to first-generation anticoagulant of coumatetralyl and coumatetralyl baits were highly palatable. The laboratory findings prompted to evaluate the efficacy of first-generation bait in the field. The second experiment was conducted in an 18-year-old mature oil palm field to evaluate coumatetralyl rat bait in three baiting treatments to control high rat infestation with high fresh damage (18%; 12%; 15%; 17%) of Rattus rattus diardii. The coumatetralyl wax bait was evaluated with one bait per palm (replacement at 4 days interval), three baits per palm (replacement at 7 days interval) and five baits per palm (replacement at 7 days interval); and an untreated control treatment was included. All the three baiting treatments provided successful control of rats and reduced the rat population to a negligible level. The standard baiting treatment required nine baiting rounds. The three baits per palm and five baits per palm treatments needed eight and five baiting rounds respectively. The fresh damage on fresh fruit bunches (FFB) in all the three treatments were observed to have reduced from high level to 0 per cent. The first-generation coumatetralyl anticoagulant bait was effective for the control of Rattus rattus diardii. Hence, it is good approach to use the first-generation baits (for example coumatetralyl bait) in susceptible rat population areas until such time the change to second generation rodenticide bait is required. Placements of more baits required fewer baiting rounds but may result in over application of baits which lead to high cost. Therefore, multiple bait application is not recommended for routine baiting campaigns. It is relatively an interim measure for quick reduction of rat populations especially in high infestation areas. Keywords: Oil palm, high rat population, baiting, first-generation anticoagulant, coumatetralyl, Rattus rattus diardii.

Household rat infestation in urban slum populations: Development and validation of a predictive score for leptospirosis.

Domestic rats are the principal reservoir for urban leptospirosis. However, few studies have identified infestation markers in slums and evaluated their predictivity for leptospirosis risk. We compared households with leptospirosis cases in Salvador, Brazil between 2007 and 2009 and their neighbors using a case control design, surveying for rodent infestation signs and environmental characteristics. With the 2007-2008 data, a conditional logistic regression modeling identified the peridomiciliar presence of rodent burrows (OR, 3.30; 95% CI, 1.50-7.26), rat feces (2.86; 1.24-6.59), runs (2.57; 1.06-6.22), households bordering abandoned houses (2.48; 1.04-6.02), and unplastered walls (2.22; 1.02-6.02) as risk factors and developed a predictive score for leptospirosis. With an independent data set from 2009, a receiver operating characteristic (ROC) curve analysis evaluated the prediction score performance, with the area under the curve being 0.70 (95% CI, 0.64-0.76) for score development and 0.71 (0.65-0.79) for validation. Results indicate that high proportions of urban slum households are infested with R. norvegicus. The score performed well when identifying high-risk households within slums. These findings need confirmation in other urban centers, but suggest that community-based screening for rodent infestation can allow to target rodent and environmental control measures in populations at highest risk for leptospirosis.