Overall Volume of Upper Gastrointestinal Surgery Positively Impacts Gastric Cancer Outcomes at Centers with Low Gastrectomy Volume.

BACKGROUND: The relationship between hospital volume and surgical mortality is well documented. However, complete centralization of surgical care is not always feasible. The present study investigates how overall volume of upper gastrointestinal surgery at hospitals influences patient outcomes following resection for gastric adenocarcinoma. PATIENTS AND METHODS: National Cancer Database (2010-2019) patients with pathologic stage 1-3 gastric adenocarcinoma who underwent gastrectomy were identified. Three cohorts were created: low-volume hospitals (LVH) for both gastrectomy and overall upper gastrointestinal operations, mixed-volume hospital (MVH) for low-volume gastrectomy but high-volume overall upper gastrointestinal operations, and high-volume gastrectomy hospitals (HVH). Chi-squared tests were used to analyze sociodemographic factors and surgical outcomes and Kaplan-Meier method for survival analysis. RESULTS: In total, 26,398 patients were identified (LVH: 20,099; MVH: 539; HVH: 5,760). The 5-year survival was equivalent between MVH and HVH for all stages of disease (MVH: 56.0%, HVH 55.6%; p = 0.9866) and when stratified into early (MVH: 69.9%, HVH: 65.4%; p = 0.1998) and late stages (MVH: 24.7%, HVH: 32.0%; p = 0.1480), while LVH had worse survival. After matching patients, postoperative outcomes were worse for LVH, but there was no difference between MVH and HVH in terms of adequate lymphadenectomy, margin status, readmission rates, and 90-day mortality rates. CONCLUSIONS: Despite lower gastrectomy volume for cancer, postoperative gastrectomy outcomes at centers that perform a high number of upper gastrointestinal cancer surgeries were similar to hospitals with high gastrectomy volume. These hospitals offer a blueprint for providing equivalent outcomes to high volume centers while enhancing availability of quality cancer care.

Improved reference genome of Aedes aegypti informs arbovirus vector control.

Female Aedes aegypti mosquitoes infect more than 400 million people each year with dangerous viral pathogens including dengue, yellow fever, Zika and chikungunya. Progress in understanding the biology of mosquitoes and developing the tools to fight them has been slowed by the lack of a high-quality genome assembly. Here we combine diverse technologies to produce the markedly improved, fully re-annotated AaegL5 genome assembly, and demonstrate how it accelerates mosquito science. We anchored physical and cytogenetic maps, doubled the number of known chemosensory ionotropic receptors that guide mosquitoes to human hosts and egg-laying sites, provided further insight into the size and composition of the sex-determining M locus, and revealed copy-number variation among glutathione S-transferase genes that are important for insecticide resistance. Using high-resolution quantitative trait locus and population genomic analyses, we mapped new candidates for dengue vector competence and insecticide resistance. AaegL5 will catalyse new biological insights and intervention strategies to fight this deadly disease vector.

Releasing incompatible males drives strong suppression across populations of wild and Wolbachia-carrying Aedes aegypti in Australia.

Releasing sterile or incompatible male insects is a proven method of population management in agricultural systems with the potential to revolutionize mosquito control. Through a collaborative venture with the "Debug" Verily Life Sciences team, we assessed the incompatible insect technique (IIT) with the mosquito vector Aedes aegypti in northern Australia in a replicated treatment control field trial. Backcrossing a US strain of Ae. aegypti carrying Wolbachia wAlbB from Aedes albopictus with a local strain, we generated a wAlbB2-F4 strain incompatible with both the wild-type (no Wolbachia) and wMel-Wolbachia Ae. aegypti now extant in North Queensland. The wAlbB2-F4 strain was manually mass reared with males separated from females using Verily sex-sorting technologies to obtain no detectable female contamination in the field. With community consent, we delivered a total of three million IIT males into three isolated landscapes of over 200 houses each, releasing ∼50 males per house three times a week over 20 wk. Detecting initial overflooding ratios of between 5:1 and 10:1, strong population declines well beyond 80% were detected across all treatment landscapes when compared to controls. Monitoring through the following season to observe the ongoing effect saw one treatment landscape devoid of adult Ae. aegypti early in the season. A second landscape showed reduced adults, and the third recovered fully. These encouraging results in suppressing both wild-type and wMel-Ae. aegypti confirms the utility of bidirectional incompatibility in the field setting, show the IIT to be robust, and indicate that the removal of this arbovirus vector from human-occupied landscapes may be achievable.

Trends in access to minimally invasive pancreaticoduodenectomy for pancreatic cancers.

BACKGROUND: Minimally invasive pancreaticoduodenectomy (MIPD), including robotic (RPD) and laparoscopy (LPD), is becoming more frequently employed in the management of pancreatic ductal adenocarcinoma (PDAC), though the majority of operations are still performed via open approach (OPD). Access to technologic advances often neglect the underserved. Whether disparities in access to MIPD exist, remain unclear. METHODS: The National Cancer Database (NCDB) was queried (2010-2020) for patients who underwent pancreatoduodenectomy for PDAC. Cochran-Armitage tests assessed for trends over time. Social determinants of health (SDH) were compared between approaches. Multinomial logistic models identified predictors of MIPD. RESULTS: Of 16,468 patients, 80.03 % underwent OPD and 19.97 % underwent MIPD (22.60 % robotic; 77.40 % laparoscopic). Black race negatively predicted LPD (vs white (OR 0.822; 95 % CI 0.701-0.964)). Predictors of RPD included Medicare/other government insurance (vs uninsured or Medicaid (OR 1.660; 95 % CI 1.123-2.454)) and private insurance (vs uninsured or Medicaid (OR 1.597; 95 % CI 1.090-2.340)). Early (2010-2014) vs late (2015-2020) diagnosis, stratified by race, demonstrated an increase in Non-White patients undergoing OPD (13.15 % vs 14.63 %; p = 0.016), but not LPD (11.41 % vs 13.57 %;p = 0.125) or RPD (14.15 % vs 15.23 %; p = 0.774). CONCLUSION: SDH predict surgical approach more than clinical stage, facility type, or comorbidity status. Disparities in race and insurance coverage are different between surgical approaches.

The Impact of the COVID-19 Pandemic on Hepatocellular Carcinoma Time to Treatment Initiation: A National Cancer Database Study.

BACKGROUND: The COVID-19 pandemic strained oncologic care access and delivery, yet little is known about how it impacted hepatocellular carcinoma (HCC) management. Our study sought to evaluate the annual effect of the COVID-19 pandemic on time to treatment initiation (TTI) for HCC. METHODS: The National Cancer Database was queried for patients diagnosed with clinical stages I-IV HCC (2017-2020). Patients were categorized based on their year of diagnosis as "Pre-COVID" (2017-2019) and "COVID" (2020). TTI based on stage and type of treatment first received was compared by the Mann-Whitney U test. A logistic regression model was used to evaluate factors of increased TTI and treatment delay (> 90 days). RESULTS: In total, 18,673 patients were diagnosed during Pre-COVID, whereas 5249 were diagnosed during COVID. Median TTI for any first-line treatment modality was slightly shorter during the COVID year compared with Pre-COVID (49 vs. 51 days; p < 0.0001), notably in time to ablation (52 vs. 55 days; p = 0.0238), systemic therapy (42 vs. 47 days; p < 0.0001), and radiation (60 vs. 62 days; p = 0.0177), but not surgery (41 vs. 41 days; p = 0.6887). In a multivariate analysis, patients of Black race, Hispanic ethnicity, and uninsured/Medicaid/Other Government insurance status were associated with increased TTI by factors of 1.057 (95% CI: 1.022-1.093; p = 0.0013), 1.045 (95% CI: 1.010-1.081; p = 0.0104), and 1.088 (95% CI: 1.053-1.123; p < 0.0001), respectively. Similarly, these patient populations were associated with delayed treatment times. CONCLUSIONS: For patients diagnosed during COVID, TTI for HCC, while statistically significant, had no clinically significant differences. However, vulnerable patients were more likely to have increased TTI.

Impact of the COVID-19 Pandemic on Delays to Breast Cancer Surgery: Ripples or Waves?

BACKGROUND: Adherence to current recommendations for optimal time from diagnosis to treatment for patients with breast cancer may have been disrupted by the COVID-19 pandemic. This study aimed to evaluate the impact of the pandemic on time to surgery or systemic treatment with chemotherapy or immunotherapy for patients diagnosed with breast cancer. METHODS: Using the National Cancer Database, patients diagnosed with breast cancer in 2020 were compared to those diagnosed from 2018-2019 (Pre-COVID). Sub-analyses were performed for patients who were tested for COVID-19 and those who had a positive result in 2020. Multivariate logistic regression was used assess odds ratios for delayed time to surgery (DTS, defined as > 90 days) or systemic therapy (defined as > 120 days). RESULTS: In total, 230,997 patients were diagnosed with breast cancer in 2018 and 2019 compared to 102,065 in 2020. Of the 2020 cohort, 47,659 (46.7%) received COVID-19 testing; of which, 3,158 (6.6%) resulted positive. A larger proportion of COVID-tested or COVID-positive patients had higher stage at diagnosis. DTS was more likely for patients who were diagnosed in 2020, uninsured or underinsured, non-white, Hispanic, less educated, or age < 70 years. Similar factors were predictive of delay to systemic therapy (less age < 70 years); however, diagnosis in 2020 was not. CONCLUSION: The COVID-19 pandemic was associated with significant DTS for breast cancer but spared time to systemic therapy. Delays disproportionately impacted vulnerable and underserved patient populations. The true clinical effects of these delays may yet be realized for breast cancer patients.

Combined High-Volume Common Complex Cancer Operations Safeguard Long-Term Survival in a Low-Volume Individual Cancer Operation Setting.

BACKGROUND: We previously demonstrated the importance of combined complex surgery volume on short-term outcomes of high-risk cancer operations. This study investigates the impact of combined common complex cancer operation volume on long-term outcomes at hospitals with low cancer-specific operation volumes. PATIENTS AND METHODS: A retrospective cohort of National Cancer Data Base (2004-2019) patients undergoing surgery for hepatocellular carcinoma, non-small cell lung cancers, or pancreatic, gastric, esophageal, or rectal adenocarcinomas was utilized. Three separate cohorts were established: low-volume hospitals (LVH), mixed-volume hospitals (MVH) with low-volume individual cancer operations and high-volume total complex operations, and high-volume hospitals (HVH). Survival analyses were performed for overall, early-, and late-stage disease. RESULTS: The 5 year survival was significantly better at MVH and HVH compared with LVH, for all operations except late-stage hepatectomy (HVH survival > LVH and MVH). The 5 year survival probability was similar between MVH and HVH for operations on late-stage cancers. Early and overall survival for gastrectomy, esophagectomy, and proctectomy were equivalent between MVH and HVH. While early and overall survival for pancreatectomy were benefited by HVH over MVH, the opposite was true for lobectomy/pneumonectomy, which were benefited by MVH over HVH; however, none of these differences were likely to have an effect clinically. Only hepatectomy patients demonstrated statistical and clinical significance in 5 year survival at HVH compared with MVH for overall survival. CONCLUSIONS: MVH hospitals performing sufficient complex common cancer operations demonstrate similar long-term survival for specific high-risk cancer operations to HVH. MVH provide an adjunctive model to the centralization of complex cancer surgery, while maintaining quality and access.

Close-kin mark-recapture methods to estimate demographic parameters of mosquitoes.

Close-kin mark-recapture (CKMR) methods have recently been used to infer demographic parameters such as census population size and survival for fish of interest to fisheries and conservation. These methods have advantages over traditional mark-recapture methods as the mark is genetic, removing the need for physical marking and recapturing that may interfere with parameter estimation. For mosquitoes, the spatial distribution of close-kin pairs has been used to estimate mean dispersal distance, of relevance to vector-borne disease transmission and novel biocontrol strategies. Here, we extend CKMR methods to the life history of mosquitoes and comparable insects. We derive kinship probabilities for mother-offspring, father-offspring, full-sibling and half-sibling pairs, where an individual in each pair may be a larva, pupa or adult. A pseudo-likelihood approach is used to combine the marginal probabilities of all kinship pairs. To test the effectiveness of this approach at estimating mosquito demographic parameters, we develop an individual-based model of mosquito life history incorporating egg, larva, pupa and adult life stages. The simulation labels each individual with a unique identification number, enabling close-kin relationships to be inferred for sampled individuals. Using the dengue vector Aedes aegypti as a case study, we find the CKMR approach provides unbiased estimates of adult census population size, adult and larval mortality rates, and larval life stage duration for logistically feasible sampling schemes. Considering a simulated population of 3,000 adult mosquitoes, estimation of adult parameters is accurate when ca. 40 adult females are sampled biweekly over a three month period. Estimation of larval parameters is accurate when adult sampling is supplemented with ca. 120 larvae sampled biweekly over the same period. The methods are also effective at detecting intervention-induced increases in adult mortality and decreases in population size. As the cost of genome sequencing declines, CKMR holds great promise for characterizing the demography of mosquitoes and comparable insects of epidemiological and agricultural significance.

A nationwide propensity score analysis comparing ablation and resection for hepatocellular carcinoma.

BACKGROUND AND OBJECTIVES: Studies have reported ambiguous results regarding the efficacy of ablation for early-stage hepatocellular carcinoma (HCC). Our study compared outcomes of ablation versus resection for HCC ≤50 mm to identify tumor sizes that would most benefit from ablation in terms of long-term survival. METHODS: The National Cancer Database was queried for patients with stage I and II HCC ≤50 mm who underwent ablation or resection (2004-2018). Three cohorts were created based on tumor size: ≤20, 21-30, and 31-50 mm. A propensity score-matched survival analysis was performed using the Kaplan-Meier method. RESULTS: In total, 36.47% (n = 4263) and 63.53% (n = 7425) of patients underwent resection and ablation, respectively. After matching, resection was associated with a significant survival benefit compared to ablation (3-year survival: 78.13% vs. 67.64%; p < 0.0001) in patients with HCC of ≤20 mm. The impact of resection was even more striking among patients with HCC of 21-30 mm (3-year survival: 77.88% vs. 60.53%; p < 0.0001) and 31-50 mm (3-year survival: 67.21% vs. 48.55%; p < 0.0001). CONCLUSIONS: While resection offers a survival benefit over ablation in the treatment of early-stage HCC ≤50 mm, ablation may provide a feasible bridging strategy in patients awaiting transplantation.

Disparities in the Receipt of Recommended Curative Treatment for Patients with Early-Stage Hepatocellular Carcinoma.

BACKGROUND: In early-stage hepatocellular carcinoma (HCC), the receipt of recommended care is critical for long-term survival. Unfortunately, not all patients decide to undergo therapy. We sought to identify factors associated with the decision to decline recommended intervention among patients with early-stage HCC. METHODS: The National Cancer Database was queried for patients diagnosed with clinical stages I and II HCC (2004-2017). Cohorts were created based on the receipt or decline of recommended interventions-hepatectomy, liver transplantation, and ablation. Multivariable logistic regression identified predictors for declining intervention, and propensity score analysis was used to calculate the respective odds. Survival analysis was performed using the Kaplan-Meier method. RESULTS: Of 20,863 patients, 856 (4.1%) declined intervention. Patients who were documented as having declined intervention were more often Black (vs. other: OR, 1.3; 95% CI, 1.1-1.6; p = 0.0038), had Medicaid or no insurance (vs. Private, Medicare, or other government insurance): OR, 1.9; 95% CI, 1.6-2.3; p < 0.0001), lived in a low-income area (vs. other: OR, 1.4; 95% CI, 1.2-1.7; p < 0.0001), and received treatment at a non-academic center (vs. academic: OR, 2.1; 95% CI, 1.9-2.5; p < 0.0001). Patients who declined recommended interventions had worse survival compared to those who received treatment (22.9 vs. 59.2 months; p < 0.0001, respectively). CONCLUSIONS: Racial and socioeconomic disparities persist in the decision to undergo recommended treatment. Underutilization of treatment acts as a barrier to addressing racial and socioeconomic disparities in early-stage HCC outcomes.

A high-quality de novo genome assembly based on nanopore sequencing of a wild-caught coconut rhinoceros beetle (Oryctes rhinoceros).

BACKGROUND: An optimal starting point for relating genome function to organismal biology is a high-quality nuclear genome assembly, and long-read sequencing is revolutionizing the production of this genomic resource in insects. Despite this, nuclear genome assemblies have been under-represented for agricultural insect pests, particularly from the order Coleoptera. Here we present a de novo genome assembly and structural annotation for the coconut rhinoceros beetle, Oryctes rhinoceros (Coleoptera: Scarabaeidae), based on Oxford Nanopore Technologies (ONT) long-read data generated from a wild-caught female, as well as the assembly process that also led to the recovery of the complete circular genome assemblies of the beetle's mitochondrial genome and that of the biocontrol agent, Oryctes rhinoceros nudivirus (OrNV). As an invasive pest of palm trees, O. rhinoceros is undergoing an expansion in its range across the Pacific Islands, requiring new approaches to management that may include strategies facilitated by genome assembly and annotation. RESULTS: High-quality DNA isolated from an adult female was used to create four ONT libraries that were sequenced using four MinION flow cells, producing a total of 27.2 Gb of high-quality long-read sequences. We employed an iterative assembly process and polishing with one lane of high-accuracy Illumina reads, obtaining a final size of the assembly of 377.36 Mb that had high contiguity (fragment N50 length = 12 Mb) and accuracy, as evidenced by the exceptionally high completeness of the benchmarked set of conserved single-copy orthologous genes (BUSCO completeness = 99.1%). These quality metrics place our assembly ahead of the published Coleopteran genomes, including that of an insect model, the red flour beetle (Tribolium castaneum). The structural annotation of the nuclear genome assembly contained a highly-accurate set of 16,371 protein-coding genes, with only 2.8% missing BUSCOs, and the expected number of non-coding RNAs. The number and structure of paralogous genes in a gene family like Sigma GST is lower than in another scarab beetle (Onthophagus taurus), but higher than in the red flour beetle (Tribolium castaneum), which suggests expansion of this GST class in Scarabaeidae. The quality of our gene models was also confirmed with the correct placement of O. rhinoceros among other members of the rhinoceros beetles (subfamily Dynastinae) in a phylogeny based on the sequences of 95 protein-coding genes in 373 beetle species from all major lineages of Coleoptera. Finally, we provide a list of 30 candidate dsRNA targets whose orthologs have been experimentally validated as highly effective targets for RNAi-based control of several beetles. CONCLUSIONS: The genomic resources produced in this study form a foundation for further functional genetic research and management programs that may inform the control and surveillance of O. rhinoceros populations, and we demonstrate the efficacy of de novo genome assembly using long-read ONT data from a single field-caught insect.

Modeling confinement and reversibility of threshold-dependent gene drive systems in spatially-explicit Aedes aegypti populations.

BACKGROUND: The discovery of CRISPR-based gene editing and its application to homing-based gene drive systems has been greeted with excitement, for its potential to control mosquito-borne diseases on a wide scale, and concern, for the invasiveness and potential irreversibility of a release. Gene drive systems that display threshold-dependent behavior could potentially be used during the trial phase of this technology, or when localized control is otherwise desired, as simple models predict them to spread into partially isolated populations in a confineable manner, and to be reversible through releases of wild-type organisms. Here, we model hypothetical releases of two recently engineered threshold-dependent gene drive systems-reciprocal chromosomal translocations and a form of toxin-antidote-based underdominance known as UDMEL-to explore their ability to be confined and remediated. RESULTS: We simulate releases of Aedes aegypti, the mosquito vector of dengue, Zika, and other arboviruses, in Yorkeys Knob, a suburb of Cairns, Australia, where previous biological control interventions have been undertaken on this species. We monitor spread to the neighboring suburb of Trinity Park to assess confinement. Results suggest that translocations could be introduced on a suburban scale, and remediated through releases of non-disease-transmitting male mosquitoes with release sizes on the scale of what has been previously implemented. UDMEL requires fewer releases to introduce, but more releases to remediate, including of females capable of disease transmission. Both systems are expected to be confineable to the release site; however, spillover of translocations into neighboring populations is less likely. CONCLUSIONS: Our analysis supports the use of translocations as a threshold-dependent drive system capable of spreading disease-refractory genes into Ae. aegypti populations in a confineable and reversible manner. It also highlights increased release requirements when incorporating life history and population structure into models. As the technology nears implementation, further ecological work will be essential to enhance model predictions in preparation for field trials.

Using spatial genetics to quantify mosquito dispersal for control programs.

BACKGROUND: Hundreds of millions of people get a mosquito-borne disease every year and nearly one million die. Transmission of these infections is primarily tackled through the control of mosquito vectors. The accurate quantification of mosquito dispersal is critical for the design and optimization of vector control programs, yet the measurement of dispersal using traditional mark-release-recapture (MRR) methods is logistically challenging and often unrepresentative of an insect's true behavior. Using Aedes aegypti (a major arboviral vector) as a model and two study sites in Singapore, we show how mosquito dispersal can be characterized by the spatial analyses of genetic relatedness among individuals sampled over a short time span without interruption of their natural behaviors. RESULTS: Using simple oviposition traps, we captured adult female Ae. aegypti across high-rise apartment blocks and genotyped them using genome-wide SNP markers. We developed a methodology that produces a dispersal kernel for distance which results from one generation of successful breeding (effective dispersal), using the distance separating full siblings and 2nd- and 3rd-degree relatives (close kin). The estimated dispersal distance kernel was exponential (Laplacian), with a mean dispersal distance (and dispersal kernel spread σ) of 45.2 m (95% CI 39.7-51.3 m), and 10% probability of a dispersal > 100 m (95% CI 92-117 m). Our genetically derived estimates matched the parametrized dispersal kernels from previous MRR experiments. If few close kin are captured, a conventional genetic isolation-by-distance analysis can be used, as it can produce σ estimates congruent with the close-kin method if effective population density is accurately estimated. Genetic patch size, estimated by spatial autocorrelation analysis, reflects the spatial extent of the dispersal kernel "tail" that influences, for example, the critical radii of release zones and the speed of Wolbachia spread in mosquito replacement programs. CONCLUSIONS: We demonstrate that spatial genetics can provide a robust characterization of mosquito dispersal. With the decreasing cost of next-generation sequencing, the production of spatial genetic data is increasingly accessible. Given the challenges of conventional MRR methods, and the importance of quantified dispersal in operational vector control decisions, we recommend genetic-based dispersal characterization as the more desirable means of parameterization.

Local introduction and heterogeneous spatial spread of dengue-suppressing Wolbachia through an urban population of Aedes aegypti.

Dengue-suppressing Wolbachia strains are promising tools for arbovirus control, particularly as they have the potential to self-spread following local introductions. To test this, we followed the frequency of the transinfected Wolbachia strain wMel through Ae. aegypti in Cairns, Australia, following releases at 3 nonisolated locations within the city in early 2013. Spatial spread was analysed graphically using interpolation and by fitting a statistical model describing the position and width of the wave. For the larger 2 of the 3 releases (covering 0.97 km2 and 0.52 km2), we observed slow but steady spatial spread, at about 100-200 m per year, roughly consistent with theoretical predictions. In contrast, the smallest release (0.11 km2) produced erratic temporal and spatial dynamics, with little evidence of spread after 2 years. This is consistent with the prediction concerning fitness-decreasing Wolbachia transinfections that a minimum release area is needed to achieve stable local establishment and spread in continuous habitats. Our graphical and likelihood analyses produced broadly consistent estimates of wave speed and wave width. Spread at all sites was spatially heterogeneous, suggesting that environmental heterogeneity will affect large-scale Wolbachia transformations of urban mosquito populations. The persistence and spread of Wolbachia in release areas meeting minimum area requirements indicates the promise of successful large-scale population transformation.

Fine-scale landscape genomics helps explain the slow spatial spread of Wolbachia through the Aedes aegypti population in Cairns, Australia.

The endosymbiotic bacterium Wolbachia suppresses the capacity for arbovirus transmission in the mosquito Aedes aegypti, and can spread spatially through wild mosquito populations following local introductions. Recent introductions in Cairns, Australia have demonstrated slower than expected spatial spread. Potential reasons for this include: (i) barriers to Ae. aegypti dispersal; (ii) higher incidence of long-range dispersal; and (iii) intergenerational loss of Wolbachia. We investigated these three potential factors using genome-wide single-nucleotide polymorphisms (SNPs) and an assay for the Wolbachia infection wMel in 161 Ae. aegypti collected from Cairns in 2015. We detected a small but significant barrier effect of Cairns highways on Ae. aegypti dispersal using distance-based redundancy analysis and patch-based simulation analysis. We detected a pair of putative full-siblings in ovitraps 1312 m apart, indicating long-distance female movement likely mediated by human transport. We also found a pair of full-siblings of different infection status, indicating intergenerational loss of Wolbachia in the field. These three factors are all expected to contribute to the slow spread of Wolbachia through Ae. aegypti populations, though from our results it is unclear whether Wolbachia loss and long-distance movement are sufficiently common to reduce the speed of spatial spread appreciably. Our findings inform the strategic deployment of Wolbachia-infected mosquitoes during releases, and show how parameter estimates from laboratory studies may differ from those estimated using field data. Our landscape genomics approach can be extended to other host/symbiont systems that are being considered for biocontrol.