Ticks and Tick-borne Diseases最新文献

Lyme borreliosis (LB) is the most common tick-borne disease (TBD) in Germany. In Bavaria, the average annual incidence of reported cases was 34.3 cases per 100,000 inhabitants between 2013 and 2020, although case numbers were presumed to be substantially higher. Since no vaccine against LB is currently available, prevention focuses on individual protection measures. This study aims to address knowledge, attitudes, and behaviours among LB cases, a population group at increased exposure to ticks, tick bites and repeated infections.

We invited Bavarian LB cases reported between weeks 23 and 35 in 2019 to participate in a questionnaire study. Questions included socio-demographic characteristics, experiences with TBDs, potential tick exposures, details of the recent episode of LB, and knowledge, attitudes, and behaviours regarding TBDs and protection measures.

Among the 377 participants, 300 were adults/adolescents, 77 were children (<14 years). Two third resided in rural areas. Although mostly well informed, a significant proportion of participants did not know or were misinformed about availability of repellents (48.5 %), risk of LB in their district (24.9 %), ticks not falling from trees (22.1 %) and non-availability of vaccination against LB (20.9 %). Even though a majority perceived checking for ticks after spending time outdoors, wearing long clothes, wearing closed shoes and tucking pants in socks as effective protection measures against tick bites, a much lower proportion applied those measures frequently (proportions perceived vs. applied: 99.2 % vs. 72.1%; 93.8 % vs. 40.2 %, 88.8 % vs. 51.1 % and 85.4 % vs. 16.8 %, respectively).

Identified lack of knowledge or misconception regarding risk factors, availability of protection measures and tick behaviour may hamper application of recommended protection measures. There appeared to be a discrepancy between perceived effectiveness and frequency of application of protection measures. Addressing identified gaps in education campaigns, specifically targeting people living in rural areas, and utilising physician-patient interactions for education are promising entry points to increase awareness and prevent TBDs. Moreover, motivators and barriers for the application of preventive behaviour should be subject of future studies.

The incidence of tick-borne infections other than Lyme borreliosis and tick-borne encephalitis is rising in Europe, including the Netherlands. Nature management workers, being highly exposed to ticks, serve as valuable sentinels for seroprevalence studies on tick-borne pathogens (TBPs). This study assessed nature management workers’ seropositivity to TBPs including Anaplasma phagocytophilum, Babesia divergens, B. microti, Borrelia burgdorferi s.l., Rickettsia conorii and R. typhi in the Netherlands. In addition, the study examined coexposure to multiple TBPs and identified risk factors for B. burgdorferi s.l.- and A. phagocytophilum-seropositivity.

The study included 525 nature management workers who donated serum and completed a questionnaire. Sera were analysed for exposure to A. phagocytophilum, B. divergens, B. microti, R. conorii and R. typhi using immunofluorescence assays. For B. burgdorferi s.l. antibody detection, the recommended two-tier testing strategy was used. Risk factor analysis was performed using logistic regression modelling.

Seropositivity was 30.9 % for B. burgdorferi s.l.; 16.4 % for A. phagocytophilum; 6.5 % for R. conorii; 2.3 % for R. typhi; 4.2 % for B. divergens; and 0.4 % for B. microti. Almost half (49.3 %) of the participants demonstrated seropositivity for one or more pathogens. Risk factors for B. burgdorferi s.l.-seropositivity included being male, increasing age and tick bite frequency. For A. phagocytophilum-seropositivity, increasing age and working in North Holland province were significant risk factors.

This study illustrates the exposure to TBPs in the Netherlands, emphasizing the need for ongoing vigilance and international collaborations to better understand and address the growing threat of TBPs in regions with demonstrated environmental TBP circulation.

Background

Neoehrlichia mikurensis infections can cause symptomatic disease, particular among immunosuppressed persons. Long-lasting asymptomatic carriage of N. mikurensis may be common in endemic areas. This study explores possible associations between carriage of N. mikurensis DNA and persistent health complaints in persons who attribute their symptoms to a tick-borne disease.

Methods

Eleven persons tested positive for N. mikurensis DNA by PCR in a study cohort of 285 persons reporting persistent health complaints. The 11 persons were tested again in a follow-up sample. Oral doxycycline treatment was given if the confirmatory PCR-test was positive. Treatment response was assessed by telephone interview. Demographics, clinical manifestations, tick exposure, physical health, somatic symptom burden and fatigue were compared to persons with negative N. mikurensis PCR (controls, N = 274).

Results

Six persons had detectable N. mikurensis DNA in a follow-up sample up to 9.5 months after the index sample. Seven persons (one without a positive confirmative test) received doxycycline treatment. Three reported symptom restitution after completed antibiotic treatment. However, their symptoms were not clearly attributed to infection by N. mikurensis. We did not find any significant differences between infected persons and non-infected controls regarding their clinical manifestations and health burdens.

Conclusions

We corroborate previous evidence of long-term carriage of N. mikurensis, but cannot infer that to be causative of persistent health complaints.

Accumulation of DNA sequence data and its use in systematics of the family Argasidae reveals new incongruencies between genera and subgenera, since several groups defined by classical taxonomy appear to be paraphyletic, which is the case of the subgenus Pavlovskyella. In order to identify morphological characters unique to one of the monophyletic groupings within Pavlovskyella and improve its system, we describe all active stages of Ornithodoros (Pavlovskyella) tartakovskyi, a species with an incomplete original description. Larvae, nymphs, males and females from Iran were examined with scanning electron microscopy (SEM). The larva of O. (P.) tartakovskyi lacks dorsal plate, posteromedian seta, postcoxal setae and a spinose area in palpal article I; the dorsal surface has 13 pairs of setae and the hypostome has two short rows of denticles in the apex only. The first nymphal instar (N1) has a micromammillated body with faint dorsal and ventral disks. The second nymphal instar (N2) shows mammillated body with an incipient hood, and dorsal disks outlined as in subsequent instars. Both N1 and N2 have a small patch of glabrous surface in the anterior margin of preanal groove, absent in posterior stages. Third nymphal instar (N3) has a small hood and lack cheeks, which are incipient in the fourth nymphal instar (N4). The four nymphal instars (N1–N4) have blunt hypostomes, striated capitula, non-mammillated legs, and 3 humps on tarsi I. Females and males of O. (P.) tartakovskyi have mammillated bodies, small cheeks not covering the capitulum, the anteromedian disk is placed anteriorly to anterior central disks, and a posterior median file of disks is merged with the median disk. We describe all postembryonic stages of O. (P.) tartakovskyi providing morphological characters that define Pavlovskyella sensu stricto and Theriodoros, a sister subgenus that includes similarly shaped species.