The presence of anti-erythrocyte autoantibodies in animals infected with various Babesia species is well reported. However, the pathogenesis of autoantibodies in babesiosis is poorly understood. Here, we demonstrated that anti-erythrocyte immunoglobulin (Ig) M and IgG were present in B. rodhaini-infected mice at 6 and 8 days after infection, respectively. Furthermore, we generated monoclonal antibodies against erythrocyte antigen from B. rodhaini-infected mice. Five clones were generated. By Western blotting analysis using whole erythrocyte antigens, one clone reacted with a broad band around 90–150 kDa, and the 2 clones reacted with a band larger than 150 kDa. B. rodhaini-infected mice and/or autoreactive monoclonal antibodies established in this study might be a powerful tool for in vivo pathogenesis studies of autoantibody development in infectious diseases.
Free-ranging cats are invasive species threatening biodiversity worldwide. They may also impose an environmental risk to humans and livestock through the transmission of zoonotic diseases. We investigated antibody levels against Toxoplasma gondii in free-ranging cats and black rats (definitive and representative intermediate hosts) by ELISA and determined their relationships with landscape environmental factors on Tokunoshima Island, Japan, the Natural World Heritage site. We found a higher seroprevalence (>70%) in both cats and black rats in landscapes where the cattle barn density was high. This was consistent with higher density of rats revealed in our trapping survey. The spatial scale of landscape factors affecting infection was broader in cats (1 km buffer radius) than in black rats (100 m buffer radius). Both cats and rats showed an increasing trend in optical density (OD) values with increasing body weight and landscape cattle barn density, suggesting that the antibody concentration increases as the chance of exposure to T. gondii in the environment increases. Thus, management actions to stop humans from feeding cats and to control rat populations without using cats are both necessary to reduce the human health risk as well as to conserve endangered species on the island.
Toxoplasma gondii is classified into 16 haplogroups based on a worldwide genotyping study of the parasite. However, only a few isolates from Japan were included in this analysis. To conduct more precise genotyping of T. gondii, we examined the genotypes of Japanese isolates in this study. DNA sequences of 6 loci were determined in 17 Japanese isolates and compared with those of strains of 16 haplogroups. As a result, Japanese isolates were classified into four groups. We investigated the virulence of some Japanese isolates and found a highly virulent strain in mice, comparable to that of RH strain, although this Japanese isolate was sister to strains of haplogroup 2, which show moderate virulence in mice. We further investigated whether this high virulence isolate had different virulence mechanism and strategy to adapt to Japanese host from other strains by comparing the virulence-related genes, ROP5, 18 and the immunomodulatory gene, ROP16 of the isolate with those of archetypical strains (GT1, ME49 and VEG). This analysis indicated the high virulence of the isolate in mice was partly explained by gene sequences of ROP5 and ROP16. These findings lead to the elucidation of biodiversity of T. gondii and have potential to optimize the diagnostic protocol.
Abstract Across Far East Asia, aspermic Fasciola forms are found endemically. They have abnormal spermatogenesis and oogenesis, and it is presumed that their progeny are produced parthenogenetically and clonally. Because of this, they are also termed parthenogenic Fasciola forms. Currently, there is no evidence that they do indeed reproduce parthenogenetically and clonally. In this study, the multilocus genetic type (MLG) in 12 microsatellite markers of adult flukes and their subsequent progeny larvae were analysed using two laboratory aspermic Fasciola triploid strains. The MLGs of adults and their larvae were identical for all markers evaluated, suggesting that these strains reproduce their progeny clonally. The deviation between theoretical and actual frequency within the larvae genotype of the Fh_6 locus resulted in the inability for self-fertilization within individual adult flukes. These findings strongly suggested that aspermic Fasciola forms reproduce their progeny by means of parthenogenesis, possibly gynogenesis.
The grasscutter (also known as the greater cane rat; Thryonomys swinderianus) is a large rodent native to West Africa that is currently under domestication process for meat production. However, little is known about the physiology of this species. In the present study, aiming to provide information about gut microbiota of the grasscutter and better understand its physiology, we investigated the intestinal microbiota of grasscutters and compared it with that of other livestock (cattle, goat, rabbit, and sheep) using 16S rRNA metagenomics analysis. Similar to the other herbivorous animals, bacteria classified as Bacteroidales, Clostridiales, Ruminococcaceae, and Lachnospiraceae were abundant in the microbiome of grasscutters. However, Prevotella and Treponema bacteria, which have fiber fermentation ability, were especially abundant in grasscutters, where the relative abundance of these genera was higher than that in the other animals. The presence of these genera might confer grasscutters the ability to easily breakdown dietary fibers. Diets for grasscutters should be made from ingredients not consumed by humans to avoid competition for resources and the ability to digest fibers may allow the use of fiber-rich feed materials not used by humans. Our findings serve as reference and support future studies on changes in the gut microbiota of the grasscutter as domestication progresses in order to establish appropriate feeding methods and captivity conditions.
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