PARTNERSHIP: BACILLUS THURINGIENSIS CRYSTAL PROTEINS FOR CONTROL OF GASTROINTESTINAL NEMATODES IN LIVESTOCK

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: ACTIVE
• Funding Source: AFRI COMPETITIVE GRANT
• Reporting Frequency: Annual
• Accession No.: 1026159
• Grant No.: 2021-67015-34574
• Cumulative Award Amt.: $646,000.00
• Proposal No.: 2020-06538
• Project Start Date: Jul 1, 2021
• Project End Date: Jun 30, 2025
• Grant Year: 2021
• Program Code: [A1221]- Animal Health and Production and Animal Products: Animal Health and Disease

Recipient Organization
UNIVERSITY OF RHODE ISLAND
19 WOODWARD HALL 9 EAST ALUMNI AVENUE
KINGSTON,RI 02881

Performing Department
Fish-Animal-Vet-Science

Non Technical Summary
Gastrointestinal nematode (GIN) parasites are common and serious infectious parasites of livestock. GIN infections have serious health and production consequences and include manifestations such as diarrhea, lethargy, weight loss and growth stunting, meat/wool/milk production loss, reduced reproductive rates, and colic manifestations. Routine deworming is a mainstay in livestock practice. However, parasite resistance to all deworming drugs (anthelmintics) is rampant, and new anthelmintics are urgently needed. This project proposes a new approach for deworming--a paraprobiotic that expresses vertebrate-safe proteins, Cry5B and/or Cry14A, with activity against nematodes. Cry5B and Cry14A are crystal (Cry) proteins produced by the bacterium Bacillus thuringiensis. Cry5B has demonstrated activity against strongylid parasites of sheep in vivo and horses in vitro and Cry14A is highly active in vitro against developing larval stages of key parasites. The aims of this project are (1) produce and test in fistulated animals new formulations to protect the paraprobiotic from premature degradation; (2) compare the efficacy of formulated Cry5B and Cry14A against key parasites of sheep (ruminants) and horses (monogastrics); and (3) perform dose-response studies of the best therapies identified. At the conclusion of this study, our goal is to have optimized a new potent and commercially viable formulated anthelmintic therapy with broad activity against GIN parasites of farm animals

Animal Health Component

50%

Research Effort Categories

Basic

(N/A)

Applied

50%

Developmental

50%

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
313	3810	1110	50%
313	3610	1110	50%

Knowledge Area
313 - Internal Parasites in Animals;

Subject Of Investigation
3610 - Sheep, live animal; 3810 - Horses, ponies, and mules;

Field Of Science
1110 - Parasitology;

Keywords

anthelmintic

bt crystal proteins

haemonchus contortus

cyathostomins

gastrointestinal nematodes

Goals / Objectives
Gastrointestinal nematodes (GIN) have a tremendous negative impact on the U.S. livestock industry. The long-term goal of this project is to establish Bacillus thuringiensis (Bt) crystal (Cry) proteins broadly as a new therapeutic modality for treating GIN parasites of livestock. Given that there are potentially many Bt Cry proteins that target GIN parasites, these studies have the potential to open up a major, new source of multiple GIN therapies.This grant has two main goals: 1. Develop formulations for delivery of anthelmintic Cry proteins against GIN parasites in ruminants and monogastric livestock.2. Compare the efficacy of two related Bt Cry proteins, Cry5B and Cry14A, against key GIN parasites of sheep (ruminant) and horses (monogastric). As part of these studies, we will also perform dose-ranging to narrow in on the minimum dose required for high anthelmintic efficacy and to establish lead candidate(s) for commercial development.The objectives of this project are as follows:1. Optimization of Cry protein delivery and stability in ruminant (sheep) and monogastric(horse) gastrointestinal tracts using ruminally fistulated sheep and cecally fistulatedhorses.2. Test the efficacy of formulated Cry5B and Cry14A in vivo against H. contortus parasitesin lambs and cyathostomin parasites in horses.3. Perform a dose-ranging study of formulation-optimized Cry(s) proteins to narrow inon the single dose required for high anthelmintic efficacy in vivo against H. contortus inlambs and cyathostomins in horses

Project Methods
YEAR 1 (YR1)Optimization of Cry protein delivery and stability in ruminant (sheep) and monogastric (horse) gastrointestinal tracts using ruminally fistulated sheep and cecally fistulated horses The aim of these studies will be to optimize formulation (enteric coating) of Cry5B IBaCC to protect from premature degradation in the digestive tract while allowing appropriate release where target parasites reside. Separate strategies will be utilized for ruminants (sheep; two different layer sizes of polymer coating Eudragit E®) and monogastrics (horses; polymer coating Eudragit® S vs. Eudragit® L) will be pursued.Production of Cry5B formulated (coated) IBaCC for monogastric and rumen stability (University of MA Medical School, UMMS): Cry5B IBaCC will be produced and bioactivity of the unformulated and formulated material validated as described below. To protect Cry5B IBaCC during passage through the monogastric (horse) and ruminant (sheep) digestive tracts, we built upon IBaCC enteric coating strategies developed for humans. We have developed scalable process methods to coat individual IBaCC particles or agglomerated particles with Eudragit®enteric controlled release polymers specific for release either into the sheep abomasum or the horse cecem.Test the stability and persistence of varying formulations of Cry5B IBaCC in the rumen of fistulated sheep (University of Rhode Island, URI): Ruminally fistulated sheep will be allocated to one of three treatments according to a 3 x 3 Latin Square design repeated twice. A 5-day washout period will follow each experimental period. During each experimental period fistulated sheep will be administered one of three Cry5 IBaCC formulations (30 mg/kg BW): 1) untreated Cry5 IBaCC, 2) Eudragit E acid-release coating of individual Cry5 IBaCC particles and 3) double Eudragit E acid-release coating of agglomerated particles. Rumen contents will be sampled at time 0, 0.5, 1, 2, 4, 6, 12, 18, 24, 36 and 48 hours. At each sampling time point rumen fluid will be collected from multiple sections of the rumen and the stability and persistence of the Cry5 IBaCC formulations in the rumen will be assessed at UMMS as described below.Test the anthelmintic efficacy of direct administration of Cry5B IBaCC into the pony cecum against cyathostomins as well as the stability of and delivery to the large intestine of varying oral formulations of Cry5B IBaCC (University of Kentucky, UK): Three cecally fistualed ponies, naturally infected with cyathostomin parasites, will be administered a single dose of Cry5B IBaCC directly into the cecum at 10 mg/kg, to determine the efficacy of Cry5B IBaCC when delivered to the target site. Fecal samples will be collected at the day of treatment and with weekly intervals for the next three weeks for determination of strongylid fecal egg counts. After a washout period of four weeks, one pony each will then be dosed orally at 30 mg/kg with 1) unformulated Cry14A, IBaCC 2). S-Eudragit Cry5B IBaCC and 3) S-Eudragit Cry14A IBaCC. Cecal content will be sampled at 0, 0.5, 1, 2, 4, 6, 12, 18, 24, 36 and 48 hours and the stability and persistence of the Cry5 IBaCC formulations will be assessed at UMMS. A Latin Square design will be used similar to the sheep study described above with a five-day washout period in between.Analysis of degradation products (UMMS). Samples will be processed for Cry5B protein gel electrophoresis. Cry5B and Cry5B degradation products can be detected via Coomassie staining or by Western blotting using an abundant rabbit polyclonal antibody to Cry5B available in the Aroian laboratory.YEAR 2 (YR2)Test the efficacy of formulated and unformulated Cry5B and Cry14A in vivo against H. contortus in lambs and cyathostomins in horses The aim of these studies will be to determine which Cry protein, Cry5B or Cry14A, is best for treating H. contortus in sheep and cyathostomins in horses using the optimized formulation identified in YR1. Production, quantitation and bioactivity validation will be assessed as previously described for all fermented products (UMMS).Anthelmintic efficacy of formulated and unformulated Cry5B IBaCC and Cry14A IBaCC in experimentally infected lambs (URI):Twenty-five lambs will be experimentally infected using an oral drench with 10,000 infective third stage larvae of H. contortus. Animals will be stratified by FEC into treatment groups (n=5) and balanced for sex and weight. Lambs will be orally administered one of five treatments: Control, formulated and unformulated Cry5B and Cry14A with all treatments dosed at 30 mg/kg BW. Anthelmintic efficacy of treatment will be evaluated by determining the fecal egg count reduction over a two week period followed by determination of worm burden at necropsy. Anthelmintic efficacy of formulated Cry14A IBaCC and Cry5B IBaCC against cyathostomins in horses (UKY):Fifteen healthy yearling miniature horses, naturally infected with mixed-species cyathostomin parasites, will be blocked by sex, ranked by decreasing magnitude of the strongylid fecal egg counts and randomly assigned to one of three treatment groups: untreated control, formulated Cry5B and Cry14A at 30 mg/kg. Fecal samples will be collected rectally on days 0, 1, 3, 7, and 14 for determination of strongylid fecal egg counts. Worm burden will be determined at necropsy.YEAR 3Dose-ranging study of formulation-optimized Cry(s) proteins to narrow in on the single dose required for high anthelmintic efficacy in vivo against H. contortus in lambs and cyathostomins in horsesProduction of optimized Cry protein formulation (UMMS):For sheep, the Cry protein with the best anthelmintic efficacy from YR2 will be produced and validated as above. Two separate fermentations, one for each large animal will be produced.Anthelmintic efficacy of varying concentrations of formulation optimized Cry5B or Cry14A in experimentally infected lambs (URI):Twenty-five lambs will be experimentally infected with 10,000 infective third stage larvae of H. contortus. Animals will be stratified by FEC into treatment groups (n=5) and balanced for sex and weight. The formulated Cry protein IBaCC with the highest efficacy from YR2 will be administered at varying concentrations (30, 15, 7.5, 3.75 and 0 mg/kg BW). Anthelmintic efficacy of treatment will be evaluated by determining the fecal egg count reduction. Anthelmintic efficacy of treatment will be evaluated by determining the fecal egg count reduction over a two week period followed by determination of worm burden at necropsy.Anthelmintic efficacy of varying doses of formulation-optimized Cry protein in vivo against cyathostomins in horses (UKY):Fifteen, naturally infected, healthy yearling miniature horses will be blocked by sex, ranked by decreasing magnitude of the strongylid fecal egg counts and randomly assigned to one of three treatment groups: . The formulated Cry protein IBaCC with the highest efficacy from YR2 will be administered at varying concentrations (15, 7.5 and 0 mg/kg BW). Fecal samples will be collected rectally on days 0, 1, 3, 7, and 14 for determination of strongylid fecal egg counts. Worm burden will be determined at necropsy.PARASITOLOGICAL AND STATISTICAL METHODS OF ANALYSIS Fecal egg counts: Strongylid fecal egg counts will be determined with the Mini-FLOTAC technique with a saturated glucose-salt solution as the flotation medium (specific gravity of 1.25) and a detection limit of 5 eggs per gram (EPG). Parasite Recovery: Recovery, enumeration and identification of sheep and horse parasites will be performed following standard laboratory procedures. Statistical analysis: Data will be analyzed in SAS, version 9.4 (Cary, NC, USA). A mixed procedure model will be constructed with worm count as outcome variable and treatment and sex as explanatory variables. Data will be interpreted at the 0.05 significance level.

Progress 07/01/23 to 06/30/24

Outputs
Target Audience:Small ruminant producers, veterinarians, extension agents and researchers in the field of Animal Science. Undergraduates and graduate students in the field of animal science. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?This project has provided opportunities for the training of graduate and undergraduate students in parasitological methods and provided professional development to graduate students participating in scientific meetings and presenting their results to both scientific and lay audiences. How have the results been disseminated to communities of interest?Results from these studies have been presented at scientific meetings and through educational presentations. What do you plan to do during the next reporting period to accomplish the goals?A study will be conducted to analyze the anthelmintic efficacy of a single dose treatment of Bacillus thuringiensisCrystal protein (Cry)in CryH18, Cry14Ab, and CryH18 in combination with cry14Ab, in vivo against Haemonchus contortus in lambs.

Impacts
What was accomplished under these goals? Objective 1: Nothing to report Objective 2: The anti-parasiticefficacy of Bacillus thuringiensis CryH18 and Cry14Ab in vivo against Haemonchus contortus in lambs was evaluated in this study. Objectives: This study analyzed the anthelmintic efficacy of a single dose treatment of Bacillus thuringiensis (Bt) Crystal (Cry) protein CryH18, Cry14Ab, and CryH18 in combination with Cry14Ab, in vivo against Haemonchus contortus in lambs.Cry proteins from Bt are being developed as novel anthelmintics with excellent efficacy of Cry5Ba demonstrated in many infection models. The aim here is to expand the list of anthelmintic proteins beyond Cry5Ba. Methods: A paraprobiotic form (IBaCC) of the Bt CryH18 and Cry14Ab was utilized in this experiment, maintaining full antiparasitic activity while unable to reproduce in the environment. Five month old Dorset lambs were infected with 10,000 H. contortus infective larvae. Once the infection was patent, lambs were stratified by fecal egg count (FEC) into one of five treatment groups (n=6). Lambs were orally administered either: Group (G)1) CryH18 (12 mg/kg BW), G2) CryH18 (6 mg/kg BW), G3) Cry14Ab (10 mg/kg BW), G4) a combination of Cry14Ab (10 mg/kg BW) and CryH18 (6 mg/kg BW), or G5) untreated control (water). FEC was measured for seven days then lambs were euthanized and their abomasums were removed. Abomasal worm burdens were quantified and characterized by sex . Results: Within 24 hours of dosing there was a reduction in FEC by 38% (95% credible interval (CI): 37-39), 30% (95% CI: 29-31), 55% (95% CI: 54-56), and 58% (95% CI: 58-59), and by the conclusion of the study there was a reduction in FEC by 57% (95% CI: 55-59), 44% (95% CI: 43-45), 63% (95% CI: 62-64), and 69% (95% CI: 69-70) in FEC for lambs in G1 through G4 versus the control (G5) lambs. respectively. Conclusions: A single dose of CryH18 (12, 6 mg/kg BW), Cry14Ab (10 mg/kg BW), and combination of Cry14Ab (10 mg/kg BW) and CryH18 (6 mg/kg BW) demonstrated anti-parasitic efficacy as evidenced by a reduction in FEC. Further studies to optimize combination treatments and identify new novel anti-parasitic Cry proteins is warranted. Objective 3: Nothing to report.

Publications

• Type: Conference Papers and Presentations Status: Published Year Published: 2023 Citation: Kass, E., Flanagan, K., Cazeault, N., Hoang, D., Li, H., Ding, Q., Caldwell, I., Rus, F., Soto, E., Ostroff, G., Aroian, R., Nielsen, M., Petersson, K. Anthelmintic efficacy of Bacillus thuringiensis crystal protein CryH18 against monogastric and ruminant gastrointestinal nematodes. American Association of Veterinary Parasitologists (AAVP), Lexington, Ky. June 10-13, 2023. Abstract No. 75 Oral Presentation
• Type: Conference Papers and Presentations Status: Published Year Published: 2024 Citation: Katherine H. Petersson, Elizabeth P. Kass, Kelly Flanagan, Duy Hoang, Nicholas Cazeault, Hanchen Li, Qian Ding, Florentina Rus, Ernesto Soto, Martin Nielsen, Gary Ostroff, Raffi Aroian. Efficacy of Bacillus thuringiensis crystal proteins against monogastric and ruminant gastrointestinal nematodes. Conference for Research Workers in Animal Disease (CRWAD), Chicago, IL. January 20-23, 2024. Abstract No. P059. Poster.

Progress 07/01/22 to 06/30/23

Outputs
Target Audience:Small ruminant producers, veterinarians, extension agens and researchers in the field of Animal Science. Undergraduate and graduate students in the field of Animal Science. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?This project has provided opportunities for the training of graduate and undergraduate students in parasitological methods and provided professional development to graduate students participating in scientific meetings and presenting their results to both scientific and lay audiences. How have the results been disseminated to communities of interest?Results from these studies have been presented at scientific meetings and through educational presentations. What do you plan to do during the next reporting period to accomplish the goals?Dose ranging studies of other novel BtCry proteins will commence.

Impacts
What was accomplished under these goals? Gastrointestinal nematodes (GIN) have a tremendous negative impact on the U.S. livestock industry. The long-term goal of this project is to establish Bacillus thuringiensis (Bt) crystal (Cry) proteins broadly as a new therapeutic modality for treating GIN parasites of livestock. Given that there are potentially many Bt Cry proteins that target GIN parasites, these studies have the potential to open a major, new source of multiple GIN therapies. Objective 1: Optimization of BtCry protein delivery and stability in ruminant (sheep) and monogastric (horse)gastrointestinal tracts using ruminally fistulated sheep and cecally fistulated horses. Nothing to report. Objective 2: Test the efficacy of formulated Cry5B and Cry14A in vivo against H. contortus parasites in lambs and cyathostomin parasites in horses. A newly discovered active, Bacillus thuringiensis crystal (Cry) protein CryH18, formerly referred to as Cry14A, was evaluated in this study. The objectives of this study were to analyze anthelmintic efficacy of Bt CryH18: 1) In vitro against equine cyathostomins, ovine Haemonchus contortus, and swine Ascaris suum; 2) In vivo against Ancylostoma ceylancium and Heligmosomoides polygyrus in rodents; and 3) In vivo against H. contortus in ovine. All animal studies were approved by IACUC. For objective 1, larval development inhibition assays were performed against cyathostomins and H. contortus at concentrations ranging from 1100 to 0.0011 ng/ml Bt CryH18. Larval motility of A. suum was determined at 40 μg/ml Bt CryH18. BtCryH18 demonstrated robust AH activity in vitro. For objective 2, hamsters infected with A. ceylanicum and mice infected with H. polygyrus were stratified into treatment groups (n=5) and orally administered 20 mg/kg Bt Cry1H18 or 50 mg/kg Bt CryH18, respectively, on day (d) 0. Fecal egg counts (FEC) and worm burdens determined on d5 were significantly reduced in both hamsters and mice. For objective 3, lambs (n=15) were experimentally infected with 10,000 H. contortus L3i and stratified sequentially by FEC into one of three treatment groups: CryH18-15 (15 mg/kg BW), CryH18-30 (30 mg/kg BW) or control. CryH18-30 and control treatment were orally administered on d0. CryH18-15 was administered on d4. FEC were monitored daily until d7 when lambs were euthanized, and total abomasal worm counts were determined. Both CryH18-15 and CryH18-30 demonstrated reduced FECs of 84% and 95% and total worm burden reduction of 69% and 93%, respectively. In conclusion, the demonstrated antiparasitic efficacy of Bt CryH18 in both monogastric and ruminants warrants further optimization of Cry proteins. Objective 3: Perform a dose-ranging study of formulation-optimized Cry(s) proteins to narrow in on the single dose required for high anthelmintic efficacy in vivo against H. contortus in lambs and cyathostomins in horses. Nothing to report.

Publications

• Type: Conference Papers and Presentations Status: Published Year Published: 2023 Citation: Kass, E., Flanagan, K., Caldwell, I., Cazeault, N., Li, L., Rus, F., Soto, E., Nielsen, M., Ostroff, G., Aroian, R., Petersson, K. Efficacy of Bacillus thuringiensis crystal protein X against monogastric and ruminant gastrointestinal nematodes. 103rd Conference of Research Workers in Animal Diseases (CRWAD), Chicago, Il, January 22-24, 2023. Abstract No. 123. Poster presentation.
• Type: Conference Papers and Presentations Status: Published Year Published: 2023 Citation: Kass, E., Flanagan, K., Cazeault, N., Hoang, D., Li, H., Ding, Q., Caldwell, C., Rus, F., Soto, E., Ostroff, G., Aroian, R., Nielsen, M., Petersson, K. Anthelmintic efficacy of Bacillus thuringiensis crystal protein CryH18 against monogastric and ruminant gastrointestinal nematodes. 68th Association of Veterinary Parasitologists (AAVP), Lexington, KY. June 10-13, 2023. Abstract No. 75 Oral presentation.

Progress 07/01/21 to 06/30/22

Outputs
Target Audience:Small ruminant producers, veterinarians, extension agents and researchers in the field of Animal Science. Undergraduate and graduate students in the field of Animal Science. Changes/Problems:The establishment of research ponies with cannulated ceca has been discontinued. Cannulae were successfully installed in three ponies, and one research experiment was completed. However, the ponies were losing weight despite being fed with high-quality supplements and hay. Independently of each other, they each developed a large intestinal impaction, which did not resolve despite appropriate veterinary attention and care. Each of the ponies were euthanized at different dates over the course of the spring and summer, and the colon impactions were confirmed at necropsy. Given these challenges, it has been decided to abandon the cecal cannulation for this project. Instead, different treatment formulations will be evaluated using ponies and foals naturally infected with cyathostomin parasites and evaluating treatment efficacy by means of the fecal egg count reduction test. What opportunities for training and professional development has the project provided?This project has provided opportunities for the training of graduate and undergraduate students in parasitological methods and provided professional development to graduate students participatingin scienctific meetings and presenting their results to both scientific and lay audiences. How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals? Continue work on optimization of formulations to protect the integrity of the Cry proteins in the digestive tract of livestock. Dose ranging studies of optimally formulated BtCry5B and other novel BtCry proteins will commence.

Impacts
What was accomplished under these goals? Gastrointestinal nematodes (GIN) have a tremendous negative impact on the U.S. livestock industry. The long-term goal of this project is to establishBacillus thuringiensis(Bt) crystal (Cry) proteins broadly as a new therapeutic modality for treating GIN parasites of livestock. Given that there are potentially many Bt Cry proteins that target GIN parasites, these studies have the potential to open up a major, new source of multiple GIN therapies. During this reporting period studies were initiated to optimize formulations for delivery of the BtCry5B into digestive tracts of varying length and complexity. Successful development of these formulations will provide the livestock industry with much needed tools to manage gastrointestinal parasites, a major constraint to the health and productivity of grazing livestock. Objective 1: Optimization of BtCry protein delivery and stability in ruminant (sheep) and monogastric(horse) gastrointestinal tracts using ruminally fistulated sheep and cecally fistulatedhorses. This year we performed at 350 liter run of BtCry5B IBaCC at Utah, quantitated (16 mg/mL), and validated the material using in vitro and in vivo assays (Ancylstoma ceylanicum hookworms in hamsters). Eudragit K and E coated capsules were prepared, loading dry BtCry5B IBaCC into both and then coated at MCPHS, for horse and sheep studies and sent to University of Kentucky and the University of Rhode Island. Western blots of material tested using the Daisy incubator system were performed to examine BtCry5B stability. Results suggested the protein is stable in sheep rumen but the material was not well behaved on the gel, suggesting that it had clogged up in the dialysis tubing. Eudragit E coated capsules did not maintain their integrity in the Daisy incubator system, simulating the rumen environment nor did the capsules maintain integrity in the rumen of fistulated sheep. Additional formulation work is underway. Previous studies had documented 0 % efficacy of orally administered BtCry5B against equine cyathostomin parasites. The working hypothesis was that the BtCry5B was being degraded during the passage through the small intestine and that this could explain the lack of efficacy against cyathostomins, which reside in the large intestines. Three cannulated ponies were treated by administration of 10 mg/kg of iBaCC-formulated BtCry5B crystal proteins directly into the Cecum. Strongylid fecal egg counts were determined using the Parasight System (Parasight System, Inc., Lexington, KY, USA). Counts were determined in triplicate for each pony on the day of treatment and daily for the following eight days. No clear treatment effect was observed in this experiment. Objective 2: Test the efficacy of formulated Cry5B and Cry14Ain vivoagainstH. contortusparasitesin lambs and cyathostomin parasites in horses. Nothing to report Objective 3: Perform a dose-ranging study of formulation-optimized Cry(s) proteins to narrow inon the single dose required for high anthelmintic efficacy in vivoagainstH. contortusinlambs and cyathostomins in horses Nothing to report

Publications

• Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: Kass, E, Smith, D, Li, H, Garceau, C, Chicca, J, Rus, F, Flanagan, K , Ostroff, G, Aroian, R. Petersson, K. Efficacy of Bacillus thuringiensis crystal protein 5B IBaCC against an experimental infection of Haemonchus contortus in lambs. World Association for the Advancement of Veterinary Parasitology (WAAVP), Dublin, Ireland, Virtual meeting. July 19-22, 2021. Oral presentation.
• Type: Books Status: Published Year Published: 2022 Citation: Kass, E., Li, H., Smith, D., Chicca, J., Rus, F., Flanagan, K, Garceau, C., Ostroff, G., Aroian, R., Nielsen, M., Petersson, K. Efficacy of various Bacillus thuringiensis crystal proteins IBaCC against ovine Haemonchus contortus and equine Cyathostomins. American Association of Veterinary Parasitologists (AAVP), Snowbird, UT. June 24-28, 2022. Abstract No. 17 Poster presentation.
• Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: Flanagan, KA, Kass, E, Smith, D, Gazzola, D, Li, H, Rus, F, Chicca, J, Garceau, C, Ostroff, G, Aroian, RV and Petersson, KH. Optimization studies of a new modality of deworming: Cry5B IBaCC. Association of Veterinary Parasitologists (AAVP), Lexington, KY. June 19-22, 2021. Abstract No. 14 Oral presentation.