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Mosquitoes (Diptera: Culicidae) are one of the most studied groups of arthropods worldwide due to their high transmission capacity for pathogens, including viruses and parasites. During June to October 2022, the prevalence of mosquito species in 12 intensive pig farms from 12 representative administrative regions in Hunan province of China was investigated using traps with ultraviolet light. All collected mosquitoes were counted and identified to species according to morphological and molecular methods. A total of 4,443 mosquito specimens were collected in the pig farms, and they represented one family, four genera and nine species. Culex pipiens pipiens (24%) was the most common mosquito species, followed by Armigeres subalbatus (23.4%) and Culex tritaeniorhynchus (20.6%). Phylogenetic analyses based on mitochondrial cox1 sequences revealed all mosquito species from present study grouping into distinct monophyletic groups corresponding to nine known mosquito species with strongly supported. The results of the present investigation have implications for the ongoing control of mosquito infestation in pig farms in Hunan province, China. This is the first report of mosquito populations in intensive pig farms in Hunan province, China.Highlights: •This is the first report of mosquito populations in intensive pig farms in Hunan province, China. •A total of 4,443 mosquito specimens were collected and they represented one family, four genera and nine species. [ABSTRACT FROM AUTHOR]

Cattle ticks (Rhipicephalus microplus) are important economic ectoparasites causing direct and indirect damage to cattle and leading to severe economic losses in cattle husbandry. It is common knowledge that R. microplus is a species complex including five clades; however, the relationships within the R. microplus complex remain unresolved. In the present study, we assembled the complete mitochondrial genome of clade C by next-generation sequencing and proved its correctness based on long PCR amplification. It was 15,004 bp in length and consisted of 13 protein genes, 22 transfer genes, and two ribosomal genes located in the two strains. There were two copies of the repeat region (pseudo-nad1 and tRNA-Glu). Data revealed that cox1, cox2, and cox3 genes were conserved within R. microplus with small genetic differences. Ka/Ks ratios suggested that 12 protein genes (excluding nad6) may be neutral selection. The genetic and phylogenetic analyses indicated that clade C was greatly close to clade B. Findings in the current study provided more data for the identification and differentiation of the R. microplus complex and made up for the lack of information about R. microplus clade C. [ABSTRACT FROM AUTHOR]

The domestic pig louse Haematopinus suis (Linnaeus, 1758) (Phthiraptera: Anoplura) is a common ectoparasite of domestic pigs, which can act as a vector of various infectious disease agents. Despite its significance, the molecular genetics, biology and systematics of H. suis from China have not been studied in detail. In the present study, the entire mitochondrial (mt) genome of H. suis isolate from China was sequenced and compared with that of H. suis isolate from Australia. We identified 37 mt genes located on nine circular mt minichromosomes, 2.9 kb-4.2 kb in size, each containing 2-8 genes and one large non-coding region (NCR) (1,957 bp-2,226 bp). The number of minichromosomes, gene content, and gene order in H. suis isolates from China and Australia are identical. Total sequence identity across coding regions was 96.3% between H. suis isolates from China and Australia. For the 13 protein-coding genes, sequence differences ranged from 2.8%-6.5% consistent nucleotides with amino acids. Our result is H. suis isolates from China and Australia being the same H. suis species. The present study determined the entire mt genome of H. suis from China, providing additional genetic markers for studying the molecular genetics, biology and systematics of domestic pig louse. [ABSTRACT FROM AUTHOR]

Culex mosquitoes (Diptera: Culicidae) can transmit a variety of arthropod-borne viruses (arboviruses), causing human and animal diseases. Cx. vishnui, Cx. pseudovishnui, and Cx. tritaeniorhynchus are three representative species in Culex vishnui subgroup, which are widely distributed in southeast Asia, and they have been proved as the main vectors transmitting Japanese encephalitis virus (JEV) that could cause human infectious mosquito-borne disease across Asia. However, the epidemiology, biology, and even molecular information of those mosquitos remain poorly understood, and only the mitochondrial genome (mitogenome) of Cx. tritaeniorhynchus has been reported in these species. In the present study, we sequenced and annotated the complete mitogenome sequence of Cx. vishnui which was 15,587 bp in length, comprising 37 genes. Comparisons of nucleotide and amino acid sequences between Cx. vishnui and Cx. tritaeniorhynchus revealed that most genes within Culex vishnui subgroup were conserved, except atp8, nad1, atp6, and nad6, with differences of 0.4 (rrnS) — 15.1% (tRNAs) and 0 (nad4L) — 9.4% (atp8), respectively, interestingly suggesting the genes nad4L and rrnS were the most conserved but atp8 gene was the least. The results based on nucleotide diversity also supported a relatively uniform distribution of the intraspecific differences in Cx. vishnui and Cx. tritaeniorhynchus with only one highly pronounced peak of divergence centered at the control region. Phylogenetic analyses using concatenated amino acid sequences of 13 protein-coding genes supported the previous taxonomic classification of the family Culicidae and the monophyly of tribes Aedini, Culicini, Mansoniini, and Sabethini. The present study revealed detailed information on the subgroup Culex vishnui, reanalyzed the relationships within the family Culicidae, provided better markers to identify and distinguish Culex species, and offered more markers for studying the molecular epidemiology, population genetics, and molecular phylogenetics of Cx. vishnui. [ABSTRACT FROM AUTHOR]

The cattle tick (Rhipicephalus microplus) is one of the most common ticks parasitizing livestock, causing diseases as the vector of pathogens. In this study, we amplified and sequenced the complete mitochondrial (mt) genome of R. microplus from Hainan province of China and compared it with that of R. microplus from Guizhou province of China. The mt genome sequence of R. microplus from Hainan isolate was 15,163 bp in size, which was significantly longer (299 bp) than R. microplus from Guizhou isolate. Nucleotide sequence difference in the entire mt genome except for non-coding region was 5.6% between R. microplus from Hainan and Guizhou isolates. For the 13 protein-coding genes, this comparison revealed the sequence differences of nucleotide (3.8–10.1%) and amino acid (1.2–17.3%). Phylogenetic analysis of R. microplus indicated that R. microplus from Hainan isolate clustered in clade A, and R. microplus from Guizhou isolate clustered in clade B. Taken together, the findings support the recent proposal the existence of two lineages (clades A and B) of R. microplus in China. [ABSTRACT FROM AUTHOR]