Resistance to pyrethroids and the relationship between adult resistance and knockdown resistance (kdr) mutations in Aedes albopictus in dengue surveillance areas of Guizhou Province, China.

The Ae. albopictus mosquito has gained global attention due to its ability to transmit viruses, including the dengue and zika. Mosquito control is the only effective way to manage dengue fever, as no effective treatments or vaccines are available. Insecticides are highly effective in controlling mosquito densities, which reduces the chances of virus transmission. However, Ae. albopictus has developed resistance to pyrethroids in several provinces in China. Pyrethroids target the voltage-gated sodium channel gene (VGSC), and mutations in this gene may result in knockdown resistance (kdr). Correlation studies between resistance and mutations can assist viruses in managing Ae. albopictus, which has not been studied in Guizhou province. Nine field populations of Ae. albopictus at the larval stage were collected from Guizhou Province in 2022 and reared to F1 to F2 generations. Resistance bioassays were conducted against permethrin, beta-cypermethrin, and deltamethrin for both larvae and adults of Ae. albopictus. Kdr mutations were characterized by PCR and sequencing. Additionally, the correlation between the kdr allele and pyrethroid resistance was analyzed. All nine populations of Ae. albopictus larvae and adults were found to be resistant to three pyrethroid insecticides. One kdr mutant allele at codon 1016, one at 1532 and three at 1534 were identified with frequencies of 13.86% (V1016G), 0.53% (I1532T), 58.02% (F1534S), 11.69% (F1534C), 0.06% (F1534L) and 0.99% (F1534P), respectively. Both V1016G and F1534S mutation mosquitoes were found in all populations. The kdr mutation F1534S was positively correlated with three pyrethroid resistance phenotypes (OR > 1, P < 0.05), V1016G with deltamethrin and beta-cypermethrin resistance (OR > 1, P < 0.05) and F1534C only with beta-cypermethrin resistance (OR > 1, P < 0.05). Current susceptibility status of wild populations of Ae. albopictus to insecticides and a higher frequency of kdr mutations from dengue-monitored areas in Guizhou Province are reported in this paper. Outcomes of this study can serve as data support for further research and development of effective insecticidal interventions against Ae. albopictus populations in Guizhou Province.

Epidemiological and clinical characteristics of scrub typhus in Guizhou Province, China: An outbreak study of scrub typhus.

The reported cases of scrub typhus (ST) have continued to escalate, with outbreaks occurring regionally in China. These pose an increasing public health threat at a time when public health has been overwhelmed. During the period from July to August 2022, in Rongjiang County, Guizhou Province, China, 13 out of 21 fever patients were diagnosed with scrub typhus, based on epidemiological investigation and blood test analysis. The major clinical symptoms of these patients showed fever, chills, headache, eschar, fatigue and pneumonia, which were accompanied by a rise in C-reactive protein, neutrophils, alanine transaminase (ALT) and aspartate aminotransferase (AST). Furthermore, nearly half of them exhibited abnormal electrocardiogram activity. Through semi-nested PCR, Sanger sequencing and phylogenetic tree construction, the Karp strain of Orientia tsutsugamushi (O. tsutsugamushi) was confirmed as the pathogen causing ST in Rongjiang County, which shared the same evolutionary branch with O. tsutsugamushi isolated from wild mouse liver or spleen, indicating that the wild mouse plays an important role in transmitting the disease. In contrast to the sporadic cases in the past, our study is the first to disclose an epidemic and the corresponding clinical characteristics of ST in Guizhou province, which is of great significance for the prevention and treatment of regional illnesses.

Characterization of bacterial communities in ticks parasitizing cattle in a touristic location in southwestern China.

The purpose of this study was to investigate tick species around Mount Fanjing and analyze bacterial communities in two species - Rhipicephalus microplus and Haemaphysalis longicornis - parasitizing cattle in Tongren, Guizhou province, Southwest China, using high-throughput sequencing methods. In April 2019, ticks were collected from five sites in Jiangkou County, Yinjiang County, and Songtao County. In total, 296 ticks were collected, comprising two genera and three species: H. longicornis, Haemaphysalis flava, and R. microplus. Rhipicephalus microplus was the most representative species (57.4%) within the collected group, being the dominant species in Tongren City, followed by H. longicornis (39.5%) and H. flava (3.0%). Beta-diversity analysis revealed differences in bacterial community composition among the tick species. The bacterial community structure of R. microplus collected in the three counties was highly similar. Chlorella and Bacillus were highly abundant in H. longicornis. Rickettsia was detected at high relative abundance in R. microplus but in low relative abundance in H. longicornis, suggesting that Rickettsia is more associated with R. microplus than with H. longicornis. More in-depth investigations are needed to determine the pathogenic risk of Rickettsia and its relationship with the host. This is the first survey on tick-borne bacterial communities in this area, which is of great significance for the prevention and control of tick-borne diseases locally.

Two new species of Achipteriidae (Acari, Oribatida) from China.

Two new species of Achipteriidae, Dentachipteria sidorchukae sp. nov. from moss and Cubachipteria clavata sp. nov. from soil in Yunnan Province, Southwest China are described and illustrated. Dentachipteria sidorchukae sp. nov. is most similar to Dentachipteria ringwoodensis but can be distinguished from the latter by the following characterstics: 3 or 4 pteromorphic denticles, seta in thickened, not reaching distal parts of lamellae. Cubachipteria clavata sp. nov. is most similar to Cubachipteria maxsellnicki, but can be distinguished from the latter by the following characterstics: seta in setiform, slightly barbed, not reaching distal parts of lamellae, seta le smooth, inserted ventrally on the lamellae.

A new species and two newly recorded species of the subgenus Pergalumna (Pergalumna) (Acari, Oribatida, Galumnidae) from China.

A new species, Pergalumna (Pergalumna) sidorchukae sp. nov., and two newly recorded species, Pergalumna (Pergalumna) jongkyui and Pergalumna (Pergalumna) amorpha, of oribatid mites of the subgenus Pergalumna (Pergalumna) from China, are described and illustrated in this study. The new species is similar to Pergalumna (Pergalumna) yurtaevi, but it differs from the latter by the surface of notogaster, the shape and size of notogastral porose areas, and the absence of postanal porose area.

New species and new records of the subgenus Galumnella (Galumnella) (Acari: Oribatida: Galumnellidae) from China.

Two new species of oribatid mites of the subgenus Galumnella (Galumnella) (Acari: Oribatida: Galumnellidae) are described from soil and litter of forest zones of China. Galumnella (G.) nonporosa sp. nov. differs from Galumnella (G.) nipponica by the falciform bothridial setae and obvious reticulate pattern in the anogenital region. Galumnella (G.) sidorchukae sp. nov. differs from Galumnella (G.) cellularis by the laciniate bothridial setae and by the absence of postanal porose area. Morphological additions to the description of Galumnella (G.) parageographica are presented based on Chinese specimens, which is recorded in China for the first time.

Two new species of the subgenus Papillacarus (Oribatida, Lohmanniidae, Papillacarus) from China.

Two new species of Lohmanniidae, Papillacarus (Papillacarus) retinervius sp. nov. from soil in Hainan Province, South China and Papillacarus (Papillacarus) mammilatus sp. nov. from moss and soil in Guizhou Province, Southwest China are described and illustrated. Papillacarus (P.) retinervius sp. nov. is most similar to Papillacarus (P.) polygonatus (Ermilov Anichkin, 2011), however, it can be distinguished from the latter by the following characterstics: 20-21 pairs of additional neotrichal setae, setae d2, e2, h1, p1 shorter, as long as d1, epimeral setal formula 10-8-4-3. Papillacarus (P.) mammilatus sp. nov. is most similar to Papillacarus (P.) angulatus (Wallwork, 1962), however, it can be distinguished from the latter by the following characterstics: transverse bands S3 complete, eight pairs of subcapitular setae, epimeral setal formula 10-6-3-4.