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Dermacentor nuttalli has been a focus of study because tick-borne pathogens have been widely identified in this tick from northern and southwestern China. The aim of this study was to characterize the life cycle of D. nuttalli under laboratory conditions and to detect spotted fever group (SFG) Rickettsia in the midgut and salivary glands of both field-collected and first laboratory generation adults. D. nuttalli ticks were collected in the field on the Qinghai-Tibetan Plateau from March to April 2021 and their life cycle was studied under laboratory conditions. Tick identify was molecularly confirmed, and SFG Rickettsia were detected in the midgut and salivary glands of males and females by PCR targeting different rickettsial genes. The results showed that the life cycle of D. nuttalli under laboratory conditions was completed in an average of 86.1 days. High positivity of Rickettsia spp. was detected in the midgut and salivary glands of both males (92.0%) and females (93.0%) of field-collected D. nuttalli ticks. However, a relatively lower positivity (4.0–6.0%) was detected in first laboratory generation adults. Furthermore, sequencing analysis showed that the Rickettsia sequences obtained in this study shared 98.6 to 100% nucleotide identity with Rickettsia slovaca and Rickettsia raoultii isolated from Dermacentor spp. in China. Phylogenetic analysis of Rickettsia spp. based on the gltA, ompA, ompB and sca4 genes revealed that the Rickettsia sequences obtained could be classified as belonging to R. slovaca and R. raoultii clades. This study described for the first time the life cycle of D. nuttalli from the Qinghai-Tibetan Plateau under laboratory conditions. Two species of SFG Rickettsia were detected in the midgut and salivary glands of males and females in both field-collected and first laboratory-generation adults of D. nuttalli. Our study provides new insights into pathogen detection in ticks in the Qinghai-Tibet Plateau, and the relationships among hosts, ticks, and pathogens.

Neosporosis is a worldwide infectious disease caused by intracellular parasite Neospora caninum that is a major pathogen of abortion in cattle and neurological disorders in other hosts. However, limited data are available on animals exposed to N. caninum in the Qinghai-Tibetan Plateau Area (QTPA), and little is known about whether animals in the plateau area play an important role in the epidemiology of N. caninum. Therefore, indirect ELISAs based on a combination of NcSAG1 and NcGRA7 antigens were developed to examine both N. caninum-specific IgG and IgM antibodies in Tibetan sheep, yak, cow, pig, cattle, horse, chicken, camel, and donkey from the QTPA in this study. The results showed that all current species present- IgG and IgM-positive animals, and that the overall seroprevalence of N. caninum were 18.6 (703/3,782) and 48.1% (1,820/3,782) for the IgG and IgM antibodies, respectively. Further analysis found significant differences from different altitudes in IgG in Tibetan sheep and IgM in the yak. Hence, the present serological results indicate that the tested animal populations in the QTPA are suffering from N. caninum infections or have become carriers of N. caninum antibodies. To the best of our knowledge, this is the first report on current N. caninum-infected animals in the QTPA, the first epidemiology of neosporosis in cow and camel in China, and the first record of N. caninum IgM antibodies in all the surveyed animals in China. This study provides the latest valuable data on the epidemiology of neosporosis in China and in plateau areas of the world.

Tick-borne diseases (TBDs) can cause serious economic losses and are very important to animal and public health. To date, research on TBDs has been limited in Qinghai-Tibet Plateau, China. This epidemiological investigation was conducted to evaluate the distribution and risk factors of Anaplasma spp. and Ehrlichia chaffeensis in livestock in Qinghai. A total of 566 blood samples, including 330 yaks (Bos grunniens) and 236 Tibetan sheep (Ovis aries) were screened. Results showed that A. bovis (33.3%, 110/330) and A. phagocytophilum (29.4%, 97/330) were most prevalent in yaks, followed by A. ovis (1.2%, 4/330), A. capra (0.6%, 2/330), and E. chaffeensis (0.6%, 2/330). While A. ovis (80.9%, 191/236) and A. bovis (5.1%, 12/236) infection was identified in Tibetan sheep. To our knowledge, it is the first time that A. capra and E. chaffeensis have been detected in yaks in China. Apart from that, we also found that co-infection of A. bovis and A. phagocytophilum is common in yaks (28.2%, 93/330). For triple co-infection, two yaks were infected with A. bovis, A. phagocytophilum, and A. capra, and two yaks were infected with A. bovis, A. phagocytophilum, and E. chaffeensis. Risk analysis shows that infection with A. bovis, A. phagocytophilum, and A. ovis was related to region and altitude. This study provides new data on the prevalence of Anaplasma spp. and E. chaffeensis in Qinghai, China, which may help to develop new strategies for active responding to these pathogens.

A number of studies have demonstrated that Babesia orientalis (B. orientalis) can only infect water buffalo (Bubalus bubalis) and not dairy cattle (Bos taurus) or beef cattle (Bos taurus), even though all three belong to the tribe Bovini and have close evolutionary relationships. In addition, Babesia species are intracellular protozoans that obligately parasitize in erythrocytes. This may indicate that the infection specificity is due to differences in erythrocyte proteins. Totals of 491, 1,143, and 1,145 proteins were identified from water buffalo, beef cattle, and dairy cattle, respectively, by searching the Uniprot and NCBI databases. The number of proteins identified for water buffalo was far lower than for beef cattle and dairy cattle, particularly in the range from 15 to 25 kDa. Remarkably, 290 identified proteins were unique to water buffalo, of which putative gamma-globin and putative epsilon-globin had a significant possibility of being relevant to the survival of B. orientalis only in water buffalo. A total of 2,222 proteins were annotated in terms of molecular function, biological process, and cellular component according to GO annotation. The number of proteins of water buffalo in oxygen binding was far higher than for beef cattle and dairy cattle. This is the first time that the protein profiles of water buffalo, beef cattle, and dairy cattle have been comparatively analyzed. The uniquely expressed proteins in water buffalo obtained in this study may provide new insights into the mechanism of B. orientalis infection exclusivity in water buffalo and may be a benefit for the development of strategies against B. orientalis.