Gregory David Hawley

Dr. Gregory David Hawley

University of Toronto, Toronto, Ontario, Canada
orcid

Research Focus & Metrics

Academic Career Length

2Years (2025-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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AOArghavan Omidi
Arghavan Omidi
GHGregory David Hawley
Gregory David Hawley
DKDylan Kain
Dylan Kain
FJFarah Jazuli
Farah Jazuli
MMMilca Meconnen
Milca Meconnen
ABAndrea K Boggild
Andrea K Boggild
Wilderness medicine is a rapidly evolving field and has benefited from expanded research efforts. Moreover, with an escalating occurrence of severe and cataclysmic global climatologic events, human illness arising from interaction with wilderness and recreational environments warrants increasing consideration. Within the last decade, the Wilderness Medical Society (WMS) has aggregated research findings and created guidelines on prevention measures and therapeutic options for acute altitude illness, frostbite injuries, and avalanche and non-avalanche snow burials. As new research emerges, some guidelines have been updated to reflect the most current and sound scientific conclusions. In this review, we have synthesized the evidence-based guidelines and have reviewed the quality of the guidelines according to the Appraisal of Guidelines for Research and Evaluation (AGREE) II framework. Further research efforts can expand the scope of evidence-based practice in travel medicine and ideally standardize the implementation of recommendations within both pre-travel and post-travel medical practices.

19 June 2026 in Infectious Disease Reports
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Journal Article
Open access
PDF file
AHAmanda Hempel
Amanda Hempel
GHGregory David Hawley
Gregory David Hawley
JHJahmar Hewitt
Jahmar Hewitt
MBMaxime Billick
Maxime Billick
ASAdrienne J. Showler
Adrienne J. Showler
ABAndrea K Boggild
Andrea K Boggild
In 2025, tropical medicine was shaped by advances in diagnostic technology, expanding arboviral epidemics, rapid progress in filovirus vaccine development, evolving regulatory responses to newly licensed vaccines, and translational breakthroughs addressing neglected tropical diseases. This review discusses five select developments that significantly influenced clinical practice and global health policy over the past year, highlighting the implications of each for clinicians, researchers, and public health systems.

1 September 2025 in Insects
Verified
Journal Article
Open access
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GHGregory David Hawley
Gregory David Hawley
MKMichael Klowak
Michael Klowak
SASyed Zain Ahmad
Syed Zain Ahmad
CMCandice Madakadze
Candice Madakadze
JHJahmar Hewitt
Jahmar Hewitt
ABAndrea K Boggild
Andrea K Boggild
Disinsection of aircraft and other conveyances is recommended to prevent the international spread of disease-carrying mosquitoes. A systematic review synthesized the effectiveness of adult mosquito disinsection aboard international air, marine, and land conveyances, using literature available up to 31 May 2025. Nineteen experimental trials, nine of which included an unexposed control arm, were synthesized. The studies were generally of poor quality with high risk of bias, and adherence to WHO guidelines was 33.30% (range: 18.20–60.5%). Across comparator trials of aircraft disinsection, the odds of mosquito mortality in the treated groups compared to control groups was 163.60 (95% CI 147–182), and the relative risk of mosquito death was 14.24 (95% CI 12.99–15.63). The direction of effect was consistent across mosquito species, methods of disinsection, types of aircraft, and insecticides, though the magnitude of the effect varied widely. The only WHO-recommended insecticide tested in a controlled trial was 2% d-phenothrin, which demonstrated an odds ratio of 171.70 (95% CI 139.10–212) and a relative risk of 20.08 (95% CI 16.53–24.43) for mosquito mortality. The lack of adherence to WHO guidelines raises uncertainty about the real-world effectiveness of disinsection.

9 November 2025 in Toxics
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Journal Article
Open access
PDF file
MKMichael Klowak
Michael Klowak
GHGregory David Hawley
Gregory David Hawley
SASyed Zain Ahmad
Syed Zain Ahmad
CMCandice Madakadze
Candice Madakadze
ARAquilla Reid-John
Aquilla Reid-John
ABAndrea K Boggild
Andrea K Boggild
Treatment of aircraft with insecticide in a procedure referred to as ‘disinsection’ is recommended to prevent the conveyance of arthropod vectors internationally and to mitigate the globalization of vector-borne infectious diseases. However, the full spectrum of human-based outcomes related to disinsection of conveyances has not been recently synthesized. A systematic review was conducted to evaluate the human safety and toxicity of insecticides used during the process of disinsecting international aircraft, marine vessels, rail, and ground transportation of mosquitoes. The systematic review was conducted according to the PRISMA guidelines and was registered in PROSPERO (CRD42024543998). The certainty of the evidence was rated, and key primary outcomes, including human health effects of conveyance disinsection, were synthesized. A total of 21 studies that described human health effects of conveyance disinsection and reported outcomes of safety, toxicity, and tolerability were included, and were of generally limited quality and high risk of bias, with low to very low certainty of estimates of effect. No high-quality studies investigating the safety, toxicity, or tolerability of disinsection were identified. Human health effects, including morbidity, including work days lost, adverse events including hospitalization, objective measures of insecticide toxicity, detectable and elevated urinary metabolites, and subjective reporting of symptoms consistent with acute insecticide poisoning, were reported by the small number of uncontrolled observational studies and public health surveillance reports included. Given the reports of significant morbidity, adverse events, and toxicity putatively attributable to aircraft disinsection, well-designed studies in exposed populations investigating the full range of human health impacts of disinsection on passengers and crew are urgently needed.

9 July 2026 in Parasitologia
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Journal Article
Open access
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JTJamal William Tarrabain
Jamal William Tarrabain
KAKeshini Abeyewardene
Keshini Abeyewardene
GHGregory David Hawley
Gregory David Hawley
ABAndrea K Boggild
Andrea K Boggild
Clonorchiasis is a parasitic infection caused by the trematode Clonorchis sinensis, which is endemic to East Asia but increasingly observed in non-endemic regions due to global migration. Chronic infection can lead to recurrent pyogenic cholangitis (RPC) and other hepatobiliary complications including cholangiocarcinoma. We herein review clonorchiasis and opisthorchiasis as potential contributory drivers of RPC in migrants from Southeast Asia through framing with a case of a Filipino woman residing in Canada who presented with a two-year history of intermittent right upper quadrant pain, liver enzyme derangement, and imaging features consistent with RPC. Despite negative stool ova and parasite (O&P) testing, empirical treatment with praziquantel (1800 mg three times daily for two days) led to clinical and biochemical improvement. Hepatobiliary trematodiasis, including clonorchiasis and opisthorchiasis, can be challenging to diagnose, and clonorchiasis and opisthorchiasis cannot be distinguished on clinical or radiographic grounds alone. Clonorchiasis can be challenging to diagnose in non-endemic areas due to low parasitologic test sensitivity and non-specific clinical features. Imaging findings and epidemiologic context are critical for raising clinical suspicion and guiding management. Healthcare providers in non-endemic regions should include clonorchiasis and opisthorchiasis in the differential diagnosis of unexplained cholestasis, particularly in migrants from areas endemic for clonorchiasis and opisthorchiasis. Negative stool tests do not exclude infection, and early empirical treatment may prevent irreversible hepatobiliary damage and reduce long-term malignancy risk.

Verified
Journal Article
Open access
PDF file
GHGregory David Hawley
Gregory David Hawley
CWChu Sandy Wang
Chu Sandy Wang
ABAndrea K Boggild
Andrea K Boggild
Marine envenomations are common non-infectious hazards for travelers. Lionfish, venomous fish native to Indo-Pacific waters, have become an invasive species in the Atlantic Ocean and threat to native marine ecosystems. Various control measures have been implemented in response to rapidly expanding lionfish populations, including licensed culling by recreational divers. We herein review lionfish envenomation through framing with a case that occurred during a diving trip to Curacao for the purpose of lionfish spearfishing. Following initial management in Curacao with hot water immersion, wound care, and antibiotic prophylaxis, the patient continued to have persistent swelling, bruising, and pain to the puncture site and was referred to our outpatient clinic for further evaluation. In addition to reviewing clinical syndromes and approach to management for common marine envenomations that may be encountered in the post-travel setting, we situate this case within the broader ecological context of expanding invasive species ranges with climate change and rising sea temperatures. Pre-travel providers should counsel patients at high risk for marine envenomations on preventative measures, along with how and when to seek care following exposure. Post-travel providers should be familiar with the immediate and long-term sequelae of non-infectious envenomations and intoxications, including marine exposures. Larger national and multinational collaborations are required to mitigate the effects of climate change and international marine movement on invasive species, especially those that incur risk to marine and human health alike.