Morgan Walker

Ms. Morgan Walker


Research Focus & Metrics

Academic Career Length

7Years (2020-Present)

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

Representative Publications

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MNMichael H Norris
Michael H Norris
THTran Hang
Tran Hang
MWMorgan Walker
Morgan Walker
ABAndrew Bluhm
Andrew Bluhm
DZDiansy Zincke
Diansy Zincke
NHNguyen Thi Thu Hang
Nguyen Thi Thu Hang
(1) Background: Burkholderia pseudomallei is an environmentally mediated saprophytic pathogen that can cause severe disease in humans. It is well known that B. pseudomallei survives in tropical moist soil environments worldwide, but melioidosis is gaining recognition as a public and veterinary health issue in Vietnam. The contribution of animals to human disease is unknown, necessitating further investigation. (2) Methods: Swine sera were collected from two populations, one grazing and one commercially farmed, from three provinces in Vietnam. ELISAs utilizing B. pseudomallei capsular polysaccharide (CPS), outer polysaccharide (OPS), and Hcp1 protein were used to screen serum samples. Positive samples were mapped to the commune level. Seroprevalence calculations and pig population estimates were used to approximate number of swine exposures per commune. (3) Results: Grazing pigs from Hoa Binh had significantly higher seropositivity levels (11.4%, 95% CI: 9.7–13.1) compared to farmed pigs from Ha Tinh and Nghe An (4%, 95% CI: 3.3–4.7). Average swine seropositivity rates were ~6.3% (95% CI: 5–7.9), higher than previously identified in Vietnam (~0.88%). (4) Conclusions: Initial serological sampling identified a significant number of seropositive and potential melioidosis infections occurring in swine in Vietnam. This work is a critical step in understanding the role swine may play in the epidemiology of human melioidosis in Vietnam.

1 March 2023 in The American Journal of Tropical Medicine and Hygiene
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TLTan Luong
Tan Luong
TNTat Thang Nguyen
Tat Thang Nguyen
VTVan Binh Trinh
Van Binh Trinh
MWMorgan Walker
Morgan Walker
THThi Thu Ha Hoang
Thi Thu Ha Hoang
JBJason Blackburn
Jason Blackburn
: Anthrax, caused by Bacillus anthracis, has a nearly global distribution but is understudied in Southeast Asia, including Vietnam. Here, we used historical data from 1999 to 2020 in Ha Giang, a province in northern Vietnam. The objectives were to describe the spatiotemporal patterns and epidemiology of human and livestock anthrax in the province and compare livestock vaccine coverage with human and livestock anthrax incidence. Annual incidence rates (per 10,000) for humans, buffalo/cattle, and goats were used to explore anthrax patterns and for comparison with livestock annual vaccine variations. A data subset describes anthrax epidemiology in humans by gender, age, source of infection, type of anthrax, admission site, and season. Zonal statistics and SaTScan were used to identify spatial and space-time clusters of human anthrax. SaTScan revealed space-time clusters in 1999, 2004, and 2007–2008 in the province, including in the northeastern, eastern, and western areas. Most human anthrax was reported between July and October. Most patients were male, aged 15–59 years, who had handled sick animals and/or consumed contaminated meat. High case-fatality rates were reported with gastrointestinal or respiratory cases. Our data suggest that vaccination in buffalo and cattle reduces the disease burden in humans and vaccinated animals but does not reduce the incidence in unvaccinated animals (goats). This study identified spatial areas of high risk for anthrax and can inform One Health surveillance and livestock vaccination planning in contextual settings similar to Ha Giang province.