SFTSV infection in rodents and their ectoparasitic chiggers.

SFTSV, a tick-borne bunyavirus causing a severe hemorrhagic fever termed as severe fever with thrombocytopenia syndrome (SFTS). To evaluate the potential role of rodents and its ectoparasitic chiggers in the transmission of SFTSV, we collected wild rodents and chiggers on their bodies from a rural area in Qingdao City, Shandong Province, China in September 2020. PCR amplification of the M and L segments of SFTSV showed that 32.3% (10/31) of rodents and 0.2% (1/564) of chiggers (Leptotrombidium deliense) from the rodents were positive to SFTSV. Our results suggested that rodents and chiggers may play an important role in the transmission of SFTSV, although the efficiency of chiggers to transmit SFTSV needs to be further investigated experimentally.

Rickettsia japonica and Novel Rickettsia Species in Ticks, China.

PCR amplification indicated the minimum infection rate of Rickettsia spp. was 0.66% in Haemaphysalis longicornis ticks collected from Shandong Province, China. Phylogenetic analysis based on the rrs, gltA, ompA, and ompB genes indicated that the ticks carried R. japonica, Candidatus Rickettsia longicornii, and a novel Rickettsia species related to R. canadensis.

Anaplasma species detected in Haemaphysalis longicornis tick from China.

Anaplasma are tick-borne obligatory intracellular bacteria, which infect humans and other animals. The Anaplasma species carried by ticks in China are not well studied. We collected 3145 questing Haemaphysalis longicornis ticks including 120 larvae, 2460 nymphs and 565 adults from vegetation in Jiaonan County, Shandong Province, China from 2013 to 2015. All ticks were examined for the presence of Anaplasma species by nested PCR amplification of the 16S rRNA gene. For further differentiation of A. capra from A. centrale, gltA and msp2 genes were sequenced for A. capra. Three Anaplasma species were detected in the nymph and/or adult ticks with the minimum infection rate of ticks as follows: 1.55% for A. bovis, 0.10% for A. phagocytophilum, and 0.03% for A. capra. These results indicated that the H. longicornis tick in Jiaonan County carried multiple Anaplasma species, which may be a challenge for public health in the studying area.

Seroprevalence of Severe Fever with Thrombocytopenia Syndrome Virus in Hedgehog from China.

Severe fever with thrombocytopenia syndrome, an emerging hemorrhagic fever, is caused by severe fever with thrombocytopenia syndrome virus (SFTSV), a tick-borne bunyavirus. Information regarding SFTSV animal hosts is very limited. In this study, we showed that 64% (9/14) of hedgehogs in Shandong Province, China were seropositive to SFTSV antibody, suggesting that hedgehog could be a vertebrate parasitifer for SFTSV.

Detection of Imjin Virus and Seoul Virus in Crocidurine Shrews in Shandong Province, China.

INTRODUCTION: Recently, hantaviruses have been discovered in insectivores in Europe, Asia, Africa, and North America. Imjin virus (MJNV) was first isolated from the lung tissues of Ussuri white-toothed shrew (Crocidura lasiura) from South Korea in 2009. We aim to detect the species and prevalence of insectivore- and rodent-borne hantaviruses in shrews and rodents. MATERIALS AND METHODS: Shrews and rodents were captured in Jiaonan County of Shandong Province, China, in 2014. RT-PCR was used to amplify viral RNA of Hantavirus species, including insectivore-borne Imjin virus (MJNV), rodent-borne Hantaan virus (HTNV), and Seoul virus (SEOV) from shrews and rodents. RESULTS AND DISCUSSION: We found that MJNV infected 10.7% (19/178) of Crocidura shrews, but it infected none of rodents (0/475); we also found that 2 of 178 (1.1%) Crocidura shrews were PCR positive to SEOV. This study indicated that the major animal hosts of Imjin virus are shrews, and rodent-borne SEOV can infect shrews.

Haemaphysalis longicornis Ticks as Reservoir and Vector of Severe Fever with Thrombocytopenia Syndrome Virus in China.

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging hemorrhagic fever in East Asia caused by SFTS virus (SFTSV), a newly discovered phlebovirus. The Haemaphysalis longicornis tick has been suspected to be the vector of SFTSV. To determine whether SFTSV can be transmitted among ticks, from ticks to animals, and from animals to ticks, we conducted transmission studies between developmental stages of H. longicornis ticks and between ticks and mice. Using reverse transcription PCR, we also analyzed the prevalence of SFTSV infection among H. longicornis ticks collected from vegetation in Shandong Province, China. Our results showed a low prevalence of SFTSV among collected ticks (0.2%, 8/3,300 ticks), and we showed that ticks fed on SFTSV-infected mice could acquire the virus and transstadially and transovarially transmit it to other developmental stages of ticks. Furthermore, SFTSV-infected ticks could transmit the virus to mice during feeding. Our findings indicate ticks could serve as a vector and reservoir of SFTSV.

Prevalence of SFTSV among Asian house shrews and rodents, China, January-August 2013.

To evaluate the role of small mammals as hosts of severe fever with thrombocytopenia syndrome virus (SFTSV), we tested serum samples from rodents and shrews in China, collected in 2013. SFTSV antibodies and RNA were detected, suggesting that rodents and shrews might be hosts for SFTSV.