Mark Mitchell
Director of Wildlife Hospital of Louisiana and Professor Louisiana State University
- Baton Rouge LA
Dr. Mitchell's research focus is on wildlife epidemiology, conservation medicine, and One Health.
Areas of Expertise
Research Focus
Wildlife Epidemiology & One Health
Dr. Mitchell’s research focuses on wildlife epidemiology, conservation medicine, and One Health, examining how diseases move among wildlife, people, and the environment. As director of LSU’s Wildlife Hospital of Louisiana, he combines clinical case data, field surveillance, and biostatistical modeling to guide rehabilitation, shape zoonotic-risk policy, and train future veterinarians.
Education
Louisiana State University
Ph.D.
2001
University of Illinois, Urbana-Champaign
M.S.
1996
University of Illinois, Urbana-Champaign
DVM
1992
University of Illinois, Urbana-Champaign
B.S.
1990
Accomplishments
LSU School of Veterinary Medicine Class of 2020 Commencement Speaker
2020
LSU Distinguished Thesis Award- Kimberly Boykin, Committee Chair
2020
Media Appearances
LSU zoology professor discusses bird flu, 1st human death
WHSV 3 tv
2025-01-08
Dr. Mark Mitchell is a professor of zoological medicine at LSU.
Articles
Determining the Effectiveness of Saccharomyces cerevisiae as a Postbiotic in Mass-Reared Acheta domesticus (House Cricket)
Insects2025
Pre-, pro-, and post-biotics have been used with success in several commercially grown insect species to increase yields and improve health outcomes. However, few studies have been published evaluating the use of nutritional supplements in Acheta domesticus. For this study, we fed day-old, farm-raised, A. domesticus a Saccharomyces cerevisiae postbiotic product at one of three different inclusion rates (0, 0.25, and 0.5%) for 32 days. Crickets were analyzed for differences in average weights, total biomass, percent survival, nutritional analyses, viral qPCR, and 16S/18S microbiomes. Crickets receiving the 0.5% inclusion feed trended towards having a higher total biomass (F = 3.823, p = 0.052) and a higher percent survival per bin (F = 3.667, p = 0.057) than the crickets receiving lower inclusion feeds. No significant differences were found in viral prevalences or loads. Significant changes to the microbiomes were mostly defined by increased abundances of presumed beneficial bacteria (Akkermansia, Catenibacillus, and Odoribacter) in the groups receiving postbiotics rather than by losses of harmful bacteria. For the 18S results, there was an increased abundance of a Gregarian apicomplexan, Leidyana erratica in the treatment groups. Overall, the 0.5% inclusion feed appeared to be beneficial and further study investigating other forms of feed additives is warranted.
Impact of Commercial Diets on the Nutritional Value and Mortality Rates of Dubia Roaches (Blaptica dubia)
Journal of Herpetological Medicine and Surgery2025
Dubia roaches ( Blaptica dubia ) are a popular feeder insect, but like most other insects have an inverse calcium to phosphorous (Ca:P) ratio. A plethora of insect diets claim to correct this inverse ratio, but limited evidence-based data exists. The goals of this study were to determine if diets claiming to correct the Ca:P ratio can do so, to determine the impact of diet on the nutritional value and mortality of dubia roaches, and to determine the fasting period required to empty the gut of dubia roaches. In phase one, nymphal roaches were fasted (24 hours) and randomly divided into a control group ( n = 6, baseline) and two experimental groups ( n = 6 each). Each cohort represented approximately 75-80 roaches. Roaches in the experimental groups were either fed 50 g of a high calcium diet or low calcium diet (24 hours). The Ca:P ratio was significantly higher ( P < 0.001) in the high calcium group compared to the control and low calcium diet groups. In phase two, adult roaches (25.4-31.8 mm) were fasted (24 hours) and then gut-loaded for 24 or 168 hours on a high calcium or low calcium diet ( n = 6/group). The Ca:P ratio was significantly higher ( P < 0.001) in the high calcium group compared to the low calcium diet group, regardless of time. There was no significant difference (all P > 0.06) in mortality across diets or overtime. In phase three, adult roaches were fasted (24 hours), gut loaded on the high calcium diet (24 hours), and then fasted for 24, 48, or 72 hours ( n = 3). The Ca:P ratio did not decrease over time ( P = 0.092). These results confirm that a high calcium diet can increase the Ca: P ratio in dubia roaches; however, not all gut-loading diets can alter the Ca:P ratio.
Measuring the Physiologic Effects of Tricaine Methanesulfonate Sedation in Juvenile Lemur Tree Frogs (Agalychnis lemur)
Journal of Herpetological Medicine and Surgery2025
Currently, there are more than 7700 described species of anurans. Unfortunately, amphibians are one of the most threatened classes of vertebrates. Because of this, anurans have become common in ex-situ programs. To provide a high level of care for these animals in captivity, sedation protocols are required to facilitate diagnostic and therapeutic procedures. Tricaine methanesulfonate (MS-222) has been used in anurans; however, research with this anesthetic is limited across anuran species, and dosages are highly variable. The purpose of this study was to: 1) perform a pilot study to determine a concentration of MS-222 for sedating lemur frogs ( Agalychnis lemur ), a critically endangered species, and 2) test the efficacy of this concentration for sedating 16 juvenile frogs for microcomputed tomography (mCT) scans. For the pilot study, 400 mg/L and 800 mg/L concentrations were selected. Based on rapid induction and recovery times, the 800 mg/L concentration was selected. For the sedation trial, baseline heart and gular rates and palpebral, escape, and righting reflexes were measured; these measurements were continued every 5 minutes until the frogs recovered. Frogs were induced within 5 minutes, and the mean recovery time was 38±12.6 minutes. While there was a transient reduction in heart rate after induction, it returned to baseline after the mCT scan. Gular movements decreased by 26% from baseline to recovery. All animals recovered without complications. The results of this study suggest 800 mg/L MS-222 is a safe and effective method of sedating lemur frogs for diagnostic imaging.
A Preliminary Investigation of the Gastrointestinal Bacterial Microbiomes of Barred Owls (Strix varia) Admitted to a Wildlife Hospital
Animals2025
Simple Summary Birds are vital to ecosystems, yet studies on their gut microbiome remain limited. Wildlife hospitals offer a unique opportunity to study wild birds as environmental sentinels during rehabilitation. Many receive antibiotics, but the impact on their gut bacteria and the potential spread of antibiotic-resistant bacteria after release is unclear. This study examined cloacal samples from barred owls (Strix varia), the most commonly admitted species to the Wildlife Hospital of Louisiana. Owls were randomly assigned to antibiotic-treated and non-treated groups, and their cloacal microbiomes were compared at admission and release. A significant shift in the microbiome was detected in antibiotic-treated owls compared to control owls, with a reduction in the richness and evenness of bacteria post-antibiotics. We also detected alterations in antibiotic resistance genes over time, with some acquiring new resistance genes during their hospitalization. These findings demonstrate that rehabilitating wildlife can have a minimal impact on their gastrointestinal microbiome in the absence of antibiotic treatment; however, antibiotic usage can significantly alter the microbiome and potentially increase the risk of translocating antibiotic resistance genes into naïve ecosystems. These findings can be used to guide better antibiotic practices and conservation efforts in wildlife rehabilitation.
Transcutaneous ultrasonography for visualization of the kidneys in captive Asian elephants (Elephas maximus): a quantitative assessment of echogenicity and echotexture in comparison with the [...]
BMC Veterinary Research2025
Background Kidney transcutaneous ultrasonography can be used to assess renal condition and is less invasive than transrectal ultrasonography, which typically requires intensive restraint, sedation, or general anesthesia. To date, this less invasive technique has not been evaluated in Asian elephants (Elephas maximus). The gray level histogram technique associated with transcutaneous ultrasonography is a quantitative approach to objectively measure echogenicity and echotexture. This study utilized gray-level histograms (GLH) to assess echogenicity and echotexture of the kidneys, spleen, and liver of 49 captive Asian elephants via transcutaneous ultrasonography, to obtain a baseline for healthy animals and to compare various internal organs as a reference for quantitative analyses. Results Retroperitoneal fat was the most hyperechoic region identified, followed by the spleen. The renal medullas and the left cortex were the three most homogenous tissues. No significant differences were found between the sexes or age groups. Conclusions This study found that transcutaneous ultrasonography could be used to quantitatively measure echogenicity and echotexture in captive Asian elephants using the GLH technique. Baseline GLH references were developed for healthy captive Asian elephants for renal, hepatic and splenic transcutaneous ultrasonography.
Affiliations
- Association of Reptilian and Amphibian Veterinarians : Past President
Research Grants
Determining the effects of exogenous human chorionic gonadotropin and pregnant mare serum gonadotropin on plasma testosterone and semen production in leopard geckos (Eublepharis macularius)
ACRES Grant
2020-2021
Investigating the transmission and prevalence of Acheta domesticus densovirus (AdDV) and other associated viruses within commercial cricket farms
USDA $7500
2019-2020
Developing Methods to Cryopreserve Semen in Squamates: Every Sperm is Sacred!!
LSU-Audubon Center for Research on Endangered Species
2019-2020
Media
