Pinniped populations around the world increased rapidly after hunting and culling during the nineteenth and twentieth centuries ended. Some believe that pinnipeds are now preventing the recovery of certain fish populations, and that controlling pinniped population abundance using lethal measures such as harvesting or by non-lethal means like contraception could recover fish populations. It is unclear, however, how effective and how long it would take for such methods of population control to bring numbers of pinnipeds down to target levels. We used sex- and age-structured population models to estimate how quickly harbor seal (Phoca vitulina) abundance in British Columbia, Canada, could be reduced by 50%, through combinations of lethal removals and sterilization of adult females. Models were fit to seal abundance, demographic, and harvest data collected between 1879 and 2014. Simulation modeling suggests reliance on contraception exclusively is unlikely to reduce the current harbor seal population (numbering ~100,000) by 50% within 25 years, and would result in more variable outcomes, compared to lethal removals. Contraception could be combined with harvesting to maintain a target abundance of harbor seals (although captive studies with harbor seals are needed to confirm the efficacy of contraception). Our simulation modeling approach provides a useful framework to assess how non-lethal measures could be integrated into policies that promote active population control of harbor seal numbers. 

https://onlinelibrary.wiley.com/doi/pdfdirect/10.1002/jwmg.22400

Comparing lethal and non‐lethal methods of active population control for harbor seals in British Columbia

The overabundant populations of wildlife have caused many negative impacts, such as human‐wildlife conflicts and ecological degradation. The existing approaches like injectable immunocontraceptive vaccines and lethal methods have limitations in many aspects, which has prompted the advancement of oral immunocontraceptive vaccine. There is growing interest in oral immunocontraceptive vaccines for reasons including high immunization coverage, easier administration, frequent boosting, the ability to induce systemic and mucosal immune responses, and cost‐effectiveness. Delivery systems have been developed to protect oral antigens and enhance the immunogenicity, including live vectors, microparticles and nanoparticles, bacterial ghosts, and mucosal adjuvants. However, currently, no effective oral immunocontraceptive vaccine is available for field trials because of the enormous development challenges, including biological and physicochemical barriers of the gastrointestinal tract, mucosal tolerance, pre‐existing immunity, antigen residence time in the small intestine, species specificity and other safety issues. To overcome these challenges, this article summarizes achievements in delivery systems and contraceptive antigens in oral immunocontraceptive vaccines and explores the potential barriers for future vaccine design and application.

Oral immunocontraceptive vaccines: A novel approach for fertility control in wildlife

Simple Summary Microsporidia are obligatory intracellular fungi that cause infection in a broad variety of eukaryotes. However, there are few epidemiological studies on microsporidia in red pandas in China. Therefore, we conducted an epidemiological survey of microsporidia in red pandas from six zoos in Sichuan Province, China. In 198 fecal samples, Enterocytozoon bieneusi was detected in 24 samples (12.1%), while Encephalitozoon spp. was detected in 8 fecal samples (4.0%). Further analysis revealed the presence of genotypes of E. bieneusi with zoonotic concerns. Interestingly, we also observed that the infection rate of microsporidia was higher in semi-free red pandas with more frequent contact with other animals or humans. This is the first report on the occurrence and genotypes of E. bieneusi and Encephalitozoon spp. in red pandas in Sichuan Province, China, contributing to our understanding of the worldwide distribution and genetic diversity of this pathogen. Abstract Enterocytozoon bieneusi and Encephalitozoon spp. are microsporidian pathogens with zoonotic potential that pose significant public health concerns. To ascertain the occurrence and genotypes of E. bieneusi and Encephalitozoon spp., we used nested PCR to amplify the internal transcribed spacer (ITS) gene and DNA sequencing to analyze 198 fecal samples from red pandas from 6 zoos in China. The total rate of microsporidial infection was 15.7% (31/198), with 12.1% (24/198), 1.0% (2/198), 2.0% (4/198) and 1.0% (2/198) for infection rate of E. bieneusi, Encephalitozoon cuniculi, Encephalitozoon intestinalis and Encephalitozoon hellem, respectively. One red panda was detected positive for a mixed infection (E. bieneusi and E. intestinalis). Red pandas living in semi-free conditions are more likely to be infected with microsporidia (χ2 = 6.212, df = 1, p < 0.05). Three known (SC02, D, and PL2) and one novel (SCR1) genotypes of E. bieneusi were found. Three genotypes of E. bieneusi (SC02, D, SCR1) were grouped into group 1 with public health importance, while genotype PL2 formed a separate clade associated with group 2. These findings suggest that red pandas may serve as a host reservoir for zoonotic microsporidia, potentially allowing transmission from red pandas to humans and other animals.

/pdf/occurrence-and-molecular-characteristics-of-microsporidia-in-byfl2fci.pdf

Occurrence and Molecular Characteristics of Microsporidia in Captive Red Pandas (Ailurus fulgens) in China

This study evaluated the protective effect of Bacillus subtilis HH2 on beagles orally challenged with enterotoxigenic Escherichia coli (ETEC). We assessed the physiological parameters and the severity of diarrhea, as well as the changes in three serum immunoglobulins (IgG, IgA, and IgM), plasma diamine oxidase (DAO), D-lactate (D-LA), and the fecal microbiome. Feeding B. subtilis HH2 significantly reduced the severity of diarrhea after the ETEC challenge (p < 0.05) and increased serum levels of IgG, IgA, and IgM (p < 0.01). B. subtilis HH2 administration also reduced serum levels of DAO at 48 h after the ETEC challenge (p < 0.05), but no significant changes were observed in D-LA (p > 0.05). Oral ETEC challenge significantly reduced the richness and diversity of gut microbiota in beagles not pre-fed with B. subtilis HH2 (p < 0.05), while B. subtilis HH2 feeding and oral ETEC challenge significantly altered the gut microbiota structure of beagles (p < 0.01). Moreover, 14 days of B. subtilis HH2 feeding reduced the relative abundance of Deinococcus-Thermus in feces. This study reveals that B. subtilis HH2 alleviates diarrhea caused by ETEC, enhances non-specific immunity, reduces ETEC-induced damage to the intestinal mucosa, and regulates gut microbiota composition.

/pdf/protective-effects-of-bacillus-subtilis-hh2-against-oral-3c8sqtxd.pdf

Protective Effects of Bacillus subtilis HH2 against Oral Enterotoxigenic Escherichia coli in Beagles

Corynebacterium pseudotuberculosis is a zoonotic pathogen that causes lymphadenitis in humans, livestock, and wildlife. In this study, C. pseudotuberculosis biovar equi strains were isolated from three alpacas. Antibiotic susceptibility tests and pathogenicity tests were also conducted. Moreover, one strain was sequenced using DNBSEQ and Oxford Nanopore technology. The three strains exhibited resistance to aztreonam, fosfomycin, and nitrofurantoin. The median lethal doses (LD50) of strains G1, S2 and BA3 in experimentally infected mice was 1.66 × 105 CFU, 3.78 × 105 CFU and 3.78 × 105 CFU, respectively. The sequencing of strain G1 resulted in the assembly of a chromosomal scaffold comprising 2,379,166 bp with a G + C content of 52.06%. Genome analysis of strain G1 revealed the presence of 48 virulence genes and 5 antibiotic resistance genes (ARGs). Comparative genomic analysis demonstrates a high degree of genetic similarity among C. pseudotuberculosis strains, in contrast to other Corynebacterium species, with a clear delineation between strains belonging to the two biovars (ovis and equi). The data of the present study contribute to a better understanding of the properties of C. pseudotuberculosis biovar equi strains and the potential risk they pose to alpacas and other livestock, as well as the necessity of ongoing surveillance and monitoring of infectious diseases in animals.

/pdf/isolation-characterization-and-pathogenicity-assessment-of-1hx1kny9.pdf

Isolation, characterization, and pathogenicity assessment of Corynebacterium pseudotuberculosis biovar equi strains from alpacas (Vicugna pacos) in China

Jinpeng Yang

Papers

Oral immunocontraceptive vaccines: A novel approach for fertility control in wildlife

Occurrence and Molecular Characteristics of Microsporidia in Captive Red Pandas (Ailurus fulgens) in China

Protective Effects of Bacillus subtilis HH2 against Oral Enterotoxigenic Escherichia coli in Beagles

Isolation, characterization, and pathogenicity assessment of Corynebacterium pseudotuberculosis biovar equi strains from alpacas (Vicugna pacos) in China