not-yet-known not-yet-known not-yet-known unknown Giardia duodenalis is a globally distributed zoonotic parasite primarily transmitted through the fecal-oral route, infecting various vertebrates, and the infection of which is prevalent in goats. Immune cells play a crucial role in pathogens invasion, and neutrophil extracellular traps (NETs) released by neutrophils serve as a non-specific defense mechanism against pathogens including parasites. In this study, we investigated the characteristics, components, and molecular mechanisms of goat NETs upon stimulation with G. duodenalis trophozoites. Scanning electron microscopy, immunofluorescence staining, and quantification of NETs revealed that typical goat NETs composed of DNA, citrullinated histone H3 (CitH3), and neutrophil elastase (NE) were induced by G. duodenalis trophozoites in a dose-dependent manner. Additionally, detection of reactive oxygen species (ROS) levels suggested simultaneous accumulation of ROS during Giardia infection. Furthermore, inhibitory experiments demonstrated that Giardia-induced NETs and ROS production were associated with TLR2/TLR4 signaling pathways along with NADPH oxidase (NOX), ERK 1/2 and p38 MAPK signaling pathways activation. In summary, the release of goat NETs triggered by Giardia was accompanied by ROS generation, and both processes were regulated via TLR2/TLR4, NOX, ERK 1/2, and p38 MAPK signaling pathways. This study highlights the role of NETs in immune responses to G. duodenalis infection while providing valuable insights for further investigations into the potential use of NETs-based strategies against this parasite.

The evolution of parasites is often directly affected by the host’s environment or behavior. Studies on the evolution of the same parasites in different hosts are extremely attractive and highly relevant to our understanding of divergence and speciation. Here we analyzed the genetic variation of Equus roundworm populations in different hosts (horses, zebras and donkeys), and presented the first molecular evidence of divergence in Equus roundworms (Parascaris univalens). At the genetic level, Equus roundworms were mainly separated into two clades (Horse-derived and Zebra & Donkey-derived). This divergence began at 600-1500 years ago, which interestingly coincided with the domestication history of horses. We found that compared with horse-derived roundworms, most of the key enzymes related to glycolysis were under strong positive selection in zebra & donkey-derived roundworms, indicating that the evolution of the metabolic level was one of the main reasons for the divergence. In addition, we conducted a selective scan of resistance-related genes and found that the three populations were under different degrees of selection. This prompted us to pay attention to the possible impact of drugs on divergence, not just the drug resistance. This work supports that divergence or speciation is a continuous and dynamic process, and continuous monitoring of environmental factors is conducive to further understanding the adaptive evolution of roundworms.

Ticks act as important vectors of infectious agents, and several emerging tick-borne viruses have recently been identified to be associated with human diseases in northeastern China. However, little is known about the tick virome in northeastern China. We used metatranscriptomics to investigate the virome diversity in Haemaphysalis japonica, H. concinna, Dermacentor silvarum, and Ixodes persulcatus ticks collected from northeastern China. In total, 22 RNA viruses were identified, including four each in the Nairoviridae and Phenuiviridae families, three each in the Flaviviridae, Rhabdoviridae, and Solemoviridae families, two in the Chuviridae family, and one each in the Partitiviridae, Tombusviridae families and an unclassified virus. Of these, eight viruses were novel species, belonging to the Nairoviridae (Ji’an nairovirus and Yichun nairovirus), Phenuiviridae (Mudanjiang phlebovirus), Rhabdoviridae (Tahe rhabdovirus 1-3), Chuviridae (Yichun mivirus), and Tombusviridae (Yichun tombus-like virus) families, and five members were established human pathogens, including Alongshan virus, tick-borne encephalitis virus, Songling virus, Beiji nairovirus, and Nuomin virus. I. persulcatus ticks had significant higher viral species than H. japonica, H. concinna, and D. silvarum ticks. Significant differences in tick viromes were observed among Daxing’an, Xiaoxing’an and Changbai mountains. These findings showed an extensive diversity of RNA viruses in ticks in northeastern China, revealing potential public health threats from the emerging tick-borne viruses. Further studies are needed to explain the natural circulation and pathogenicity of these viruses.

Helminth diseases have long been a threat to the health of humans and animals. Roundworms are important organisms for studying parasitic mechanisms, disease transmission and prevention. The study of parasites in the giant panda is of importance for understanding how roundworms adapt to the host. Here, we report a high-quality chromosome-scale genome of Baylisascaris schroederi with a genome size of 253.60 Mb and 19,262 predicted protein-coding genes. We found that gene families related to epidermal chitin synthesis and environmental information processes in the roundworm genome have expanded significantly. Furthermore, we demonstrated unique genes involved in essential amino acid metabolism in the B. schroederi genome, inferred to be essential for the adaptation to the giant panda-specific diet. In addition, under different deworming pressures, we found that four resistance-related genes (glc-1, nrf-6, bre-4 and ced-7) were under strong positive selection in a captive population. Finally, 23 known drug targets and 47 potential drug target proteins (essential homologues linked to lethal phenotypes) were identified. The genome provides a unique reference for inferring the early evolution of roundworms and their adaptation to the host. Population genetic analysis and drug sensitivity prediction provide insights revealing the impact of deworming history on population genetic structure of importance for disease prevention.

Helminth diseases have long been a threat to the health of humans and animals. Roundworms are important organisms for studying parasitic mechanisms, disease transmission and prevention. The study of parasites in the living fossil giant panda is of great significance for understanding the adaptation mechanism of roundworms to the host. Here, we report a high-quality chromosome-scale genome of Baylisascaris schroederi with a genome size of 262 Mb and 19,291 predicted protein-coding genes. We found a significant expansion of genes related to epidermal chitin synthesis and environmental information processing in roundworms genome. Furthermore, we demonstrated unique genes involved in essential amino acid metabolism in the B. schroederi genome, inferred to be essential for the adaptation to the giant panda-specific diet. In addition, under different deworming pressures, we found that four resistance-related genes (glc-1, nrf-6, bre-4 and ced-7) were under strong positive selection in captive population. Finally, 23 known drug targets and 47 potential target proteins were identified. The genome provides a unique reference for inferring the early evolution of roundworms and the mechanisms underlying adaptive. Population genetic analysis and drug prediction provide insights for revealing the impact of deworming history on population genetic structure and prevention.