Browsing by Author "Tompkins DM"

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    Home range overlaps of the brushtail possum (Trichosurus vulpecula): implications for disease transmission
    (Springer Verlag, 2024-08-01) Tobajas J; Richardson KS; French NP; Buddle B; Jewell C; Tompkins DM; Rouco C
    Understanding how bovine tuberculosis (TB) is maintained in wildlife reservoirs is critical for the management of this disease impacting cattle in many countries. For the primary wildlife reservoir of the disease in New Zealand, the brushtail possum (Trichosurus vulpecula), transmission of this contagious bacterial disease among possums is often assumed to be linked to home range overlap. Identifying drivers of possum home range, and home range overlap between individuals, is thus important for informing wildlife reservoir TB management in New Zealand. We monitored four sub-populations of free-living possums in New Zealand native forests during 10 consecutive months using live trapping, to give the first direct insight into how the frequency and area of overlaps alters with density, sex and age. A total of 832 individuals were captured (average 9.3, range from 1 to 40 captures per animal with a median value of 7) and 35,820 home range overlaps were recorded. Both the number and area of overlaps were significantly associated with age class, with 66.6% of overlaps occurring between adults, 30% between adults and juveniles, and only 3.4% between juveniles. Overall, adult males showed significantly higher numbers of overlaps than expected, while adult and juvenile females showed significantly lower numbers of overlaps than expected and no differences were observed in juvenile males. In addition, males exhibited more and larger overlaps than females. The number and size of overlaps per individual decreased with increasing local population density. Understanding shared areas of activity among individuals can provide insights into the interactions occurring and potential pathways for diseases transmitted by contact such as TB. These results can inform to develop effective strategies for the control of diseases carried and dispersed by possums.
  • Thumbnail Image
    Item
    New insight into avian malaria vectors in New Zealand
    (BioMed Central Ltd, 2024-03-22) Schoener ER; Tompkins DM; Howe L; Castro IC
    BACKGROUND: Mosquitoes (Culicidae) are vectors for most malaria parasites of the Plasmodium species and are required for Plasmodium spp. to complete their life cycle. Despite having 16 species of mosquitoes and the detection of many Plasmodium species in birds, little is known about the role of different mosquito species in the avian malaria life cycle in New Zealand. METHODS: In this study, we used nested polymerase chain reaction (PCR) and real-time PCR to determine Plasmodium spp. prevalence and diversity of mitochondrial cytochrome b gene sequences in wild-caught mosquitoes sampled across ten sites on the North Island of New Zealand during 2012-2014. The mosquitoes were pooled by species and location collected, and the thorax and abdomens were examined separately for Plasmodium spp. DNA. Akaike information criterion (AIC) modeling was used to test whether location, year of sampling, and mosquito species were significant predictors of minimum infection rates (MIR). RESULTS: We collected 788 unengorged mosquitoes of six species, both native and introduced. The most frequently caught mosquito species were the introduced Aedes notoscriptus and the native Culex pervigilans. Plasmodium sp DNA was detected in 37% of matched thorax and abdomen pools. When considered separately, 33% of abdomen and 23% of thorax pools tested positive by nested PCR. The MIR of the positive thorax pools from introduced mosquito species was 1.79% for Ae. notoscriptus and 0% for Cx. quinquefasciatus, while the MIR for the positive thorax pools of native mosquito species was 4.9% for Cx. pervigilans and 0% for Opifex fuscus. For the overall MIR, site and mosquito species were significant predictors of Plasmodium overall MIR. Aedes notoscriptus and Cx. pervigilans were positive for malaria DNA in the thorax samples, indicating that they may play a role as avian malaria vectors. Four different Plasmodium lineages (SYAT05, LINN1, GRW6, and a new lineage of P (Haemamoeba) sp. AENOT11) were identified in the pooled samples. CONCLUSIONS: This is the first detection of avian Plasmodium DNA extracted from thoraxes of native Culex and introduced Aedes mosquito species in New Zealand and therefore the first study providing an indication of potential vectors in this country.
  • Thumbnail Image
    Item
    Practitioner perspectives on informing decisions in One Health sectors with predictive models
    (Springer Nature Limited, 2025-12-01) Pepin KM; Carlisle K; Chipman RB; Cole D; Anderson DP; Baker MG; Benschop J; Bunce M; Binny RN; French N; Greenhalgh S; O’Neale DRJ; McDougall S; Morgan FJ; Muellner P; Murphy E; Plank MJ; Tompkins DM; Hayman DTS
    The continued emergence of challenges in human, animal, and environmental health (One Health sectors) requires public servants to make management and policy decisions about system-level ecological and sociological processes that are complex, poorly understood, and change over time. Relying on intuition, evidence, and experience for robust decision-making is challenging without a formal assimilation of these elements (a model), especially when the decision needs to consider potential impacts if an action is or is not taken. Models can provide assistance to this challenge, but effective development and use of model-based evidence in decision-making (‘model-to-decision workflow’) can be challenging. To address this gap, we examined conditions that maximize the value of model-based evidence in decision-making in One Health sectors by conducting 41 semi-structured interviews of researchers, science advisors, operational managers, and policy decision-makers with direct experience in model-to-decision workflows (‘Practitioners’) in One Health sectors. Broadly, our interview guide was structured to understand practitioner perspectives about the utility of models in health policy or management decision-making, challenges and risks with using models in this capacity, experience with using models, factors that affect trust in model-based evidence, and perspectives about conditions that lead to the most effective model-to-decision workflow. We used inductive qualitative analysis of the interview data with iterative coding to identify key themes for maximizing the value of model-based evidence in One Health applications. Our analysis describes practitioner perspectives for improved collaboration among modelers and decision-makers in public service, and priorities for increasing accessibility and value of model-based evidence in One Health decision-making. Two emergent priorities include establishing different standards for development of model-based evidence before or after decisions are made, or in real-time versus preparedness phases of emergency response, and investment in knowledge brokers with modeling expertise working in teams with decision-makers.