Emerging tick-borne infections in mainland China: an increasing public health threat.
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ABSTRACT:
SUBMITTER: Fang LQ
PROVIDER: S-EPMC4870934 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Most tick-related studies in Europe have been conducted in nonurban areas, but ticks and tick-borne pathogens also occur in urban green spaces. From a public health perspective, risks regarding tick-borne infections should be studied in these urban areas, where contacts between infected ticks and humans may be more frequent than elsewhere, due to high human activity. We examined the risk of encountering an infected tick in urban green spaces in Helsinki, Finland. We collected ticks at nine sites throughout Helsinki, recorded the prevalence of several pathogens and identified areas with a high potential for contacts between infected ticks and humans. Moreover, we explored the relationship between the density of Borrelia burgdorferi sensu lato-infected ticks and locally diagnosed cases of borreliosis and compared the potential for human-tick encounters in Helsinki to those in nonurban areas in south-western Finland. During 34.8 km of cloth dragging, 2,417 Ixodes ricinus were caught (402 adults, 1,399 nymphs and 616 larvae). From analysed nymphs, we found 11 distinct tick-borne pathogens, with 31.5% of nymphs carrying at least one pathogen. Tick activity was highest in August and September, leading to the density of nymphs infected with B. burgdorferi s.l., and concurrently infection risk, to also be highest during this time. Nymph densities varied between the sampling sites, with obvious implications to spatial variation in infection risk. While ticks and tick-borne pathogens were found in both Helsinki and nonurban areas in south-western Finland, the estimates of human activity were generally higher in urban green spaces, leading to a higher potential for human-tick contacts therein. The presence of ticks and tick-borne pathogens and high local human activity in urban green spaces suggest that they form potential foci regarding the acquisition of tick-borne infections. Risk areas within cities should be identified and knowledge regarding urban ticks increased.
| S-EPMC7702030 | biostudies-literature
Project description: Not available
| S-EPMC10017848 | biostudies-literature
Project description:Babesiosis is a typical zoonotic, emerging disease caused by a tick-borne intraerythrocytic protozoan of Babesia spp. that also can be transmitted by blood transfusion. Babesiosis imposes an increasing public-health threat. We reviewed and mapped epidemiological studies on Babesia in vectors and/or rodents in the People's Republic of China (P.R. China) and found that B. microti was the predominant species detected in the investigated regions such as Heilongjiang, Zhejiang, Fujian provinces and Taiwan island. We reviewed a series of sporadic human babesiosis cases collected from 1940's to 2013, in Yunnan, Inner Mongolia, Taiwan and Zhejiang and other regions including a main endemic area of malaria on the China-Myanmar border areas in P.R. China. Clinical manifestations of human babesiosis were also reviewed. Human babesiosis may have previously been overlooked in P.R. China due to a lack of medical awareness and the limitation of clinical diagnostic methods.
| S-EPMC4254216 | biostudies-literature
Project description:BackgroundDengue Fever (DF) is a viral disease primarily transmitted by Aedes (Ae.) aegypti mosquitoes. Outbreaks in Eastern Ethiopia were reported during 2014-2016. In May 2017, we investigated the first suspected DF outbreak from Kabridahar Town, Somali region (Eastern Ethiopia) to describe its magnitude, assess risk factors, and implement control measures.MethodsSuspected DF cases were defined as acute febrile illness plus ≥2 symptoms (headache, fever, retro-orbital pain, myalgia, arthralgia, rash, or hemorrhage) in Kabridahar District residents. All reported cases were identified through medical record review and active searches. Severe dengue was defined as DF with severe organ impairment, severe hemorrhage, or severe plasma leakage. We conducted a neighborhood-matched case-control study using a subset of suspected cases and conveniently-selected asymptomatic community controls and interviewed participants to collect demographic and risk factor data. We tested sera by RT-PCR to detect dengue virus (DENV) and identify serotypes. Entomologists conducted mosquito surveys at community households to identify species and estimate larval density using the house index (HI), container index (CI) and Breteau index (BI), with BI≥20 indicating high density.ResultsWe identified 101 total cases from May 12-31, 2017, including five with severe dengue (one death). The attack rate (AR) was 17/10,000. Of 21 tested samples, 15 (72%) were DENV serotype 2 (DENV 2). In the case-control study with 50 cases and 100 controls, a lack of formal education (AOR [Adjusted Odds Ratio] = 4.2, 95% CI [Confidence Interval] 1.6-11.2) and open water containers near the home (AOR = 3.0, 95% CI 1.2-7.5) were risk factors, while long-lasting insecticide treated-net (LLITN) usage (AOR = 0.21, 95% CI 0.05-0.79) was protective. HI and BI were 66/136 (49%) and 147 per 100 homes (147%) respectively, with 151/167 (90%) adult mosquitoes identified as Ae. aegypti.ConclusionThe epidemiologic, entomologic, and laboratory investigation confirmed a DF outbreak. Mosquito indices were far above safe thresholds, indicating inadequate vector control. We recommended improved vector surveillance and control programs, including best practices in preserving water and disposal of open containers to reduce Aedes mosquito density.
| S-EPMC7845954 | biostudies-literature
Project description:BackgroundTick-borne relapsing fever (TBRF) is the most common vector-borne bacterial disease in humans in West Africa. It is frequently clinically confused with malaria. Our study aims to determine, on a micro-geographic scale, the conditions for the maintenance and spread of TBRF in the Niakhar district of Senegal.Methodology/principal findingsWe conducted clinical, entomological and animal reservoir investigations. Field surveys were carried out in order to investigate the presence of Ornithodoros sonrai vector ticks and to detect Borrelia spp. by qPCR using the 16S rRNA and glpQ genes, respectively. Micromammal trapping series were carried out inside homes and Borrelia infection was detected using brain tissue qPCR. Capillary blood samples from febrile patients were also tested for Borrelia using qPCR. More than 97% (40/41) of the villages surveyed were infested with O. sonrai ticks. The prevalence of Borrelia spp. infections in ticks was 13% (116/910), and over 73% (85/116) were positively confirmed as being Borrelia crocidurae. Borreliosis cases accounted for 12% (94/800) of episodes of fever and all age groups were infected, with children and young people between the ages of 8-14 and 22-28 being the most infected by the disease (16% and 18.4%). TBRF cases occurred in all seasons, with a peak in August. In two species of small rodents that were found to be infected (Arvicanthis niloticus, Mus musculus), the proportion of Borrelia infection was 17.5% (10/57), and the highest prevalence of infection (40.9%, 9/22) was observed in A. niloticus.Conclusion/significanceOur study indicates that TBRF is an endemic disease in the Niakhar district, where children and young people are the most infected. Arvicanthis niloticus and O. sonrai ticks are massively present and appear to be the main epidemiological reservoirs causing its extensive spread to humans.
| S-EPMC8096072 | biostudies-literature
Project description:Tularemia is a bacterial disease of humans, wild, and domestic animals. Francisella tularensis, which is a Gram-negative coccobacillus-shaped bacterium, is the causative agent of tularemia. Recently, an increase in the number of human tularemia cases has been noticed in several countries around the world. It has been reported mostly from North America, several Scandinavian countries, and certain Asian countries. The disease spreads through vectors such as mosquitoes, horseflies, deer flies, and ticks. Humans can acquire the disease through direct contact of sick animals, consumption of infected animals, drinking or direct contact of contaminated water, and inhalation of bacteria-loaded aerosols. Low infectious dose, aerosol route of infection, and its ability to induce fatal disease make it a potential agent of biological warfare. Tularemia leads to several clinical forms, such as glandular, ulceroglandular, oculoglandular, oropharyngeal, respiratory, and typhoidal forms. The disease is diagnosed through the use of culture, serology, or molecular methods. Quinolones, tetracyclines, or aminoglycosides are frequently used in the treatment of tularemia. No licensed vaccine is available in the prophylaxis of tularemia and this is need of the time and high-priority research area. This review mostly focuses on general features, importance, current status, and preventive measures of this disease.
| S-EPMC7521936 | biostudies-literature
Project description:Tick-borne encephalitis (TBE) is one of the most important viral zoonosis transmitted by the bite of infected ticks. In this study, all tick-borne encephalitis virus (TBEV) E gene sequences available in GenBank as of June 2019 with known date of isolation (n = 551) were analyzed. Simulation studies showed that a sample bias could significantly affect earlier studies, because small TBEV datasets (n = 50) produced non-overlapping intervals for evolutionary rate estimates. An apparent lack of a temporal signal in TBEV, in general, was found, precluding molecular clock analysis of all TBEV subtypes in one dataset. Within all subtypes and most of the smaller groups in these subtypes, there was evidence of many medium- and long-distance virus transfers. These multiple random events may play a key role in the virus spreading. For some groups, virus diversity within one territory was similar to diversity over the whole geographic range. This is best exemplified by the virus diversity observed in Switzerland or Czech Republic. These two countries yielded most of the known European subtype Eu3 subgroup sequences, and the diversity of viruses found within each of these small countries is comparable to that of the whole Eu3 subgroup, which is prevalent all over Central and Eastern Europe. Most of the deep tree nodes within all three established TBEV subtypes dated less than 300 years back. This could be explained by the recent emergence of most of the known TBEV diversity. Results of bioinformatics analysis presented here, together with multiple field findings, suggest that TBEV may be regarded as an emerging disease.
| S-EPMC7077300 | biostudies-literature
Project description:ImportanceTick-borne diseases (TBDs) other than Lyme disease, such as spotted fever group rickettsiosis, ehrlichiosis, and galactose-α-1,3-galactose (α-gal) syndrome, are an emerging public health issue. Long-term sequelae secondary to Ehrlichia or Rickettsia infection are uncommon; however, musculoskeletal symptoms are often attributed to prior tick exposure.ObjectiveTo evaluate the potential associations between prior exposure to TBDs and musculoskeletal symptoms, including radiographic osteoarthritis.Design, setting, and participantsThis cross-sectional study analyzed serum samples from the fourth visit (2017-2018) of the Johnston County Osteoarthritis (JoCo OA) project, an ongoing longitudinal, population-based study in Johnston County, North Carolina. Biospecimen testing and analysis were performed between May 2022 and November 2023. Participants in the JoCo OA project are noninstitutionalized White and Black Johnston County residents 45 years or older.Main outcome and measuresThe primary outcome was seropositivity with Ehrlichia IgG, Rickettsia IgG, and/or α-gal IgE and musculoskeletal symptoms. Secondary outcomes included risk factors associated with elevated α-gal IgE and weighted population point prevalence rates. Participants completed questionnaires, underwent physical assessments, and provided biospecimens for serological testing. Multivariable models were used to estimate associations of interest.ResultsOf the 605 participants who completed the fourth visit of the JoCo OA project, 488 (80.7%) had serum samples available for testing. The 488 participants had a median (IQR) age of 72 (68-78) years and included 336 females (68.9%) and 161 Black (33.0%) and 327 White (67.0%) individuals. The overall weighted point prevalence was 8.6% (95% CI, 5.9%-11.3%) for Ehrlichia IgG, 17.1% (95% CI, 12.6%-21.5%) for Rickettsia IgG, and 19.6% (95% CI, 15.3%-23.8%) for α-gal IgE level greater than 0.1 IU/mL. Only α-gal IgE was associated with knee pain, aching or stiffness (mean ratio, 1.30; 95% CI, 1.09-1.56). Antibodies to Rickettsia, Ehrlichia, and α-gal were not associated with symptomatic radiographic knee osteoarthritis. Male sex (odds ratio [OR], 2.63; 95% CI, 1.55-4.47), current smoker status (OR, 3.55; 95% CI, 1.38-9.18), and an attached tick bite in the past 5 years (OR, 3.99; 95% CI, 2.22-7.15) were all risk factors that were associated with α-gal IgE level greater than 0.1 IU/mL. Despite only 84 individuals (17.2%) recalling a tick bite in the past 5 years, 178 (36.5%) had evidence of prior tick-borne exposure, suggesting frequent human-tick interactions.Conclusions and relevanceResults of this cross-sectional study indicate no association between Ehrlichia or Rickettsia seropositivity and chronic musculoskeletal symptoms or osteoarthritis. Further investigation is needed into the pathogenesis of α-gal syndrome and interventions to reduce human-tick interactions.
| S-EPMC10784854 | biostudies-literature
Project description:BACKGROUND: Rickettsioses are one of the most important causes of systemic febrile illness among travelers from developed countries, but little is known about their incidence in indigenous populations, especially in West Africa. METHODOLOGY/PRINCIPAL FINDINGS: Overall seroprevalence evaluated by immunofluorescence using six rickettsial antigens (spotted fever and typhus group) in rural populations of two villages of the Sine-Saloum region of Senegal was found to be 21.4% and 51% for spotted fever group rickettsiae for Dielmo and Ndiop villages, respectively. We investigated the role of tick-borne rickettsiae as the cause of acute non-malarial febrile diseases in the same villages. The incidence of rickettsial DNA in 204 blood samples from 134 (62M and 72F) febrile patients negative for malaria was studied. DNA extracted from whole blood was tested by two qPCR systems. Rickettsial DNA was found in nine patients, eight with Rickettsia felis (separately reported). For the first time in West Africa, Rickettsia conorii was diagnosed in one patient. We also tested 2,767 Ixodid ticks collected in two regions of Senegal (Niakhar and Sine-Saloum) from domestic animals (cows, sheep, goats, donkeys and horses) by qPCR and identified five different pathogenic rickettsiae. We found the following: Rickettsia aeschlimannii in Hyalomma marginatum rufipes (51.3% and 44.8% in Niakhar and Sine-Saloum region, respectively), in Hyalomma truncatum (6% and 6.8%) and in Rhipicephalus evertsi evertsi (0.5%, only in Niakhar); R. c. conorii in Rh. e. evertsi (0.4%, only in Sine-Saloum); Rickettsia massiliae in Rhipicephalus guilhoni (22.4%, only in Niakhar); Rickettsia sibirica mongolitimonae in Hyalomma truncatum (13.5%, only in Sine-Saloum); and Rickettsia africae in Rhipicephalus evertsi evertsi (0.7% and 0.4% in Niakhar and Sine-Saloum region, respectively) as well as in Rhipicephalus annulatus (20%, only in Sine-Saloum). We isolated two rickettsial strains from H. truncatum: R. s. mongolitimonae and R. aeschlimannii. CONCLUSIONS/SIGNIFICANCE: We believe that together with our previous data on the high prevalence of R. africae in Amblyomma ticks and R. felis infection in patients, the presented results on the distribution of pathogenic rickettsiae in ticks and the first R. conorii case in West Africa show that the rural population of Senegal is at risk for other tick-borne rickettsioses, which are significant causes of febrile disease in this area.
| S-EPMC2939048 | biostudies-literature
Project description:BACKGROUND: Ticks can transmit a number of pathogens to humans and domestic animals. Tick borne diseases (TBDs), which may lead to organ failure and death have been recently reported in China. 98.75% of the total cases (>1000) in Henan provinces have been reported in Xinyang city. Therefore, the aims of this study were to investigate the fauna of ticks and detect the potential pathogens in ticks in Xinyang, the region of central China. METHODS: Ticks were collected from 10 villages of Xinyang from April to December 2012, from domestic animals including sheep, cattle and dogs. Then identification of ticks and detection of tick-borne pathogens, including Babesia spp., Theileria spp., Anaplasma spp., Ehrlichia spp., Rickettsia spp., tick-borne encephalitis virus (TBEV), Borrelia burgdorferi sensu lato, Leishmania infantum, were undertaken by using polymerase chain reaction assay (PCR) and sequence analysis. Moreover, the co-infection patterns of various pathogens were compared among locations where ticks were collected. RESULTS: A total of 308 ticks were collected. Two species of Ixodidae were found, namely Haemaphysalis longicornis (96.75%) and Rhipicephalus microplus (3.25%). Five genera of pathogens, namely Theileria spp. (3.25%), Anaplasma spp. (2.92%), Babesia spp. (1.95%), Ehrlichia spp. (2.92%) and Rickettsia spp. (0.65%), were detected in 7 villages. Co-infections by two pathogens were diagnosed in 11.11% of all infected ticks. CONCLUSIONS: Both human and animal pathogens were abundant in ticks in the study areas. Humans and animals in these regions were at a high risk of exposure to piroplasmosis, since piroplasm had the highest rates of infection and co-infection in positive ticks.
| S-EPMC4045914 | biostudies-literature