Ticks and Tick-borne Diseases最新文献

Tick-borne encephalitis virus (TBEV) is a medically important orthoflavivirus endemic across Europe and Asia, transmitted primarily by Ixodes ticks but also through ingestion of unpasteurized milk from infected ruminants. While milk-borne human infections are well documented, experimental evidence for natural mother-to-offspring transmission in livestock remains scarce. Here, we experimentally assessed the potential for lactogenic transmission of TBEV in sheep. Eight ewes were infected subcutaneously with the European subtype TBEV strain Hochosterwitz and co-housed with 16 three-week-old lambs (two per ewe) for an 18-day observation period. Clinical parameters, hematology, and virological and serological profiles were monitored. All animals remained asymptomatic, with no hematological abnormalities. TBEV RNA was detected in ewes' serum and milk from day one post-infection, and in lamb serum from day five. Virus-specific antibodies emerged in ewes from day four and in lambs from day 13. These findings provide direct experimental evidence that TBEV can be transmitted via milk from ewes to their suckling lambs throughout the lactation period, underscoring a potential but underappreciated route for virus transmission in endemic areas.

Ticks occupy diverse habitats, increasing the risk of human exposure. Assessing the public health threat posed by ticks requires rigorous monitoring of their distribution and of the prevalence of tick-borne pathogens. In France since 2017, the citizen science program CiTIQUE monitors human tick bites through multiple complementary approaches. Citizens can report bites and submit biting ticks to a national tick bank for research and surveillance. This study aimed to investigate human exposure to tick-borne microorganisms including pathogens across France, using ticks submitted through the CiTIQUE program. In total, 2009 ticks were selected from the CiTIQUE tick bank, identified, and screened for microorganisms using a real-time microfluidic PCR method. Most bites involved Ixodes ricinus nymphs except in Mediterranean regions where Dermacentor and Rhipicephalus ticks were more common. Twenty-six microorganisms were detected, eighteen of which are potentially pathogenic to humans. These pathogens were widely distributed across the country. Borrelia spp. were the most frequently detected pathogens with spatial variation among regions. Anaplasma phagocytophilum infection rates varied from region to region. Neoehrlichia mikurensis was found in seven out of twelve French regions. Rickettsia species diversity was highest in the southeast, associated with a greater diversity of vectors. Five percent of ticks were infected with more than one pathogen. Although spatial heterogeneity was observed, no region was free of infected ticks. This study demonstrates the power of citizen science for nationwide surveillance of tick-borne pathogens, providing a large-scale overview of pathogen diversity and distribution across France from crowdsourced tick data.

Rickettsia conorii Indian tick typhus strain (R. conorii subsp. indica, ITTR) was detected in both a human patient and an attached Rhipicephalus turanicus tick that was removed from the patient in Yanqi County, Xinjiang Uygur Autonomous Region (XUAR), China. The molecular identification of the pathogen, along with previous reports, suggests it may be distributed across the area. A 55-year-old female farmer presented with fever, headache, eschar, and a maculopapular rash following a tick bite. Laboratory findings indicated thrombocytopenia, liver enzyme elevation, and proteinuria, which, combined with clinical symptoms, strongly suggested a rickettsial infection. PCR and sequencing of multiple rickettsial genes confirmed the presence of ITTR in both the patient and the tick. Furthermore, the genetic identity between these sequences provided evidence that R. turanicus can act as a vector of ITTR. This case provides valuable insights into the clinical manifestation, diagnosis, and treatment of ITTR infections. These findings highlight the need for improved surveillance and awareness of tick-borne rickettsial diseases in regions with high tick exposure.

The aim of this investigation was to analyze predilection sites of ticks on avian hosts according to tick species and developmental stages, as well as individual and ecological characters of bird species (i.e., their age, habitat type, seasonality). For this, 916 ticks were removed from 289 birds in Hungary at 23 different places in the course of one year. The location of ticks on birds was recorded whenever possible. Ticks were identified as Ixodes ricinus (n=595), Ixodes frontalis (n=34), Ixodes arboricola (n=21), Ixodes acuminatus (n=1), Haemaphysalis concinna (n=246), Haemaphysalis punctata (n=16) and Hyalomma rufipes (n=3). Several new tick-host associations were revealed. Tick infestation showed predominance on juvenile birds in comparison with older ones. Among ornithophilic ticks, I. arboricola was associated with the eyes, whereas most I. frontalis larvae were collected from the ear region. Considering generalist ticks, significantly more specimens of I. ricinus were collected in the spring than during the summer, in contrast to H. concinna-infestation of birds associated with the summer. Importantly, while I. ricinus predominated in the corner of the beaks in both forested and reedbed habitats, the predilection site of H. concinna was the throat region in reedbed but the corner of beaks on forest-dwelling bird species. These findings imply that the same tick species occurred at different predilection sites during the summer depending on the typical habitat of its avian hosts. By contrast, ornithophilic tick species usually infest a narrow range of avian hosts with particular spatiotemporal distribution, allowing them to be more site-specific.