Rickettsia spp. in bats of Romania: high prevalence of Rickettsia monacensis in two insectivorous bat species

Background

Spotted fever group rickettsiae represent one of the most diverse groups of vector-borne bacteria, with several human pathogenic species showing an emerging trend worldwide. Most species are vectored by ticks (Ixodidae), with many zoonotic reservoir species among most terrestrial vertebrate groups. While the reservoir competence of many different vertebrate species is well known (e.g. birds, rodents and dogs), studies on insectivorous bats have been rarely performed despite their high species diversity, ubiquitous urban presence and importance in harboring zoonotic disease agents. Romania has a high diversity and ubiquity of bats. Moreover, seven out of eight SFG rickettsiae species with zoonotic potential were previously reported in Romania. Based on this, the aim of this study was to detect Rickettsia species in tissue samples in bats.

Methods

Here we report a large-scale study (322 bats belonging to 20 species) on the presence of Rickettsia spp. in Romanian bat species. Tissue samples from insectivorous bats were tested for the presence of Rickettsia DNA using PCR detection amplifying a 381 bp fragment of the gltA gene. Positive results were sequenced to confirm the results. The obtained results were statistically analyzed by chi-squared independence test.

Results

Positive results were obtained in 14.6% of bat samples. Sequence analysis confirmed the presence of R. monacensis in two bat species (Nyctalus noctula and Pipistrellus pipistrellus) in two locations.

Conclusion

This study provides the first evidence of a possible involvement of these bat species in the epidemiology of Rickettsia spp., highlighting the importance of bats in natural cycles of these vector-borne pathogens.

The absence of the drhm gene is not a marker for human-pathogenicity in European Anaplasma phagocytophilum strains

BACKGROUND

Anaplasma phagocytophilum is a Gram-negative obligate intracellular bacterium that replicates in neutrophil granulocytes. It is transmitted by ticks of the Ixodes ricinus complex and causes febrile illness in humans and animals. The geographical distribution of A. phagocytophilum spans the Americas, Europe, Africa and Asia. However, human disease predominantly occurs in North America but is infrequently reported from Europe and Asia. In North American strains, the absence of the drhm gene has been proposed as marker for pathogenicity in humans whereas no information on the presence or absence of the drhm gene was available for A. phagocytophilum strains circulating in Europe. Therefore, we tested 511 European and 21 North American strains for the presence of drhm and compared the results to two other typing methods: multilocus sequence typing (MLST) and ankA-based typing.

RESULTS

Altogether, 99% (478/484) of the analyzable European and 19% (4/21) of the North American samples from different hosts were drhm-positive. Regarding the strains from human granulocytic anaplasmosis cases, 100% (35/35) of European origin were drhm-positive and 100% (14/14) of North American origin were drhm-negative. Human strains from North America and Europe were both part of MLST cluster 1. North American strains from humans belonged to ankA gene clusters 11 and 12 whereas European strains from humans were found in ankA gene cluster 1. However, the North American ankA gene clusters 11 and 12 were highly identical at the nucleotide level to the European cluster 1 with 97.4% and 95.2% of identity, respectively.

CONCLUSIONS

The absence of the drhm gene in A. phagocytophilum does not seem to be associated with pathogenicity for humans per se, because all 35 European strains of human origin were drhm-positive. The epidemiological differences between North America and Europe concerning the incidence of human A. phagocytophilum infection are not explained by strain divergence based on MLST and ankA gene-based typing.

A review on the eco-epidemiology and clinical management of human granulocytic anaplasmosis and its agent in Europe

Anaplasma phagocytophilum is the agent of tick-borne fever, equine, canine and human granulocytic anaplasmosis. The common route of A. phagocytophilum transmission is through a tick bite, the main vector in Europe being Ixodes ricinus. Despite the apparently ubiquitous presence of the pathogen A. phagocytophilum in ticks and various wild and domestic animals from Europe, up to date published clinical cases of human granulocytic anaplasmosis (HGA) remain rare compared to the worldwide status. It is unclear if this reflects the epidemiological dynamics of the human infection in Europe or if the disease is underdiagnosed or underreported. Epidemiologic studies in Europe have suggested an increased occupational risk of infection for forestry workers, hunters, veterinarians, and farmers with a tick-bite history and living in endemic areas. Although the overall genetic diversity of A. phagocytophilum in Europe is higher than in the USA, the strains responsible for the human infections are related on both continents. However, the study of the genetic variability and assessment of the difference of pathogenicity and infectivity between strains to various hosts has been insufficiently explored to date. Most of the European HGA cases presented as a mild infection, common clinical signs being pyrexia, headache, myalgia and arthralgia. The diagnosis of HGA in the USA was recommended to be based on clinical signs and the patient’s history and later confirmed using specialized laboratory tests. However, in Europe since the majority of cases are presenting as mild infection, laboratory tests may be performed before the treatment in order to avoid antibiotic overuse. The drug of choice for HGA is doxycycline and because of potential for serious complication the treatment should be instituted on clinical suspicion alone.

Diversity of Flea (Siphonaptera) Parasites on Red Foxes (Vulpes vulpes) in Romania

Red foxes (Vulpes vulpes (L.)) are widespread across Europe, tolerant of synanthropic ecosystems, and susceptible to diseases potentially shared with humans and other animals. We describe flea fauna on red foxes in Romania, a large, ecologically diverse country, in part because fleas may serve as an indicator of the risk of spillover of vector-borne disease. We found 912 individual fleas of seven species on the 305 foxes assessed, for an infestation prevalence of 49.5%. Mean flea load per fox was 5.8 (range 0-44 fleas), and flea detections were most abundant in fall and early spring. Fleas included generalists (Ctenocephalides canis (Curtis), 32.6% of all fleas), Ct. felis (Bouché, 0.1%), and Pulex irritans L. (29.9%), the fox specialist Chaetopsylla globiceps (Taschenberg, 32.5%), mesocarnivore fleas Paraceras melis Walker (3.2%) and Ch. trichosa Kohaut (1.5%), and the small mammal flea Ctenophthalmus assimilis (Taschenberg, 0.1%), which is rarely or never reported from carnivores. There were significantly more female than male Ch. globiceps, Ct. canis, and Pu. irritans, and these three species were the most broadly distributed geographically. Diversity indices suggested reduced diversity in mountainous areas above 700 m. When compared to other flea studies on foxes in Europe, Romania had flea diversity near the median of reports, which was unexpected given Romania's high ecological diversity. Notably absent prey specialists, compared to other studies, include Archaeopsylla erinacei (Bouché) and Spilopsyllus cuniculi (Dale). Further studies of possible disease agents in fox fleas could help elucidate possible risks of vector-borne disease in foxes, domestic animals, and humans as well.

Angiostrongylus vasorum in Romania: an extensive survey in red foxes, Vulpes vulpes

Background

Angiostrongylus vasorum is the causative agent of canine angiostrongylosis, a severe snail-borne disease of dogs. Red foxes are important natural reservoirs of infection, and surveys of foxes provide a more objective picture of the parasite distribution. Our aim was to investigate the possibility of the presence of A. vasorum in red foxes from the western part of Romania and to analyse the risk factors related to the sex, age and geographic origin of the foxes. Between July 2016 and April 2017, 567 hunted red foxes from 10 counties of western Romania were examined by necropsy for the presence of lungworms.

Results

Overall, the infection with A. vasorum has been found in 24 red foxes (4.2%) originating in four counties (Mureș, Hunedoara, Sălaj and Cluj). There was no significant difference between the prevalence in males and females, between juveniles and adults and between counties.

Conclusions

This is the first report of autochthonous infections of A. vasorum in Romania, showing a relatively low prevalence and extending eastwards the known distributional range of this parasite in Europe. The presence of autochthonous cases in domestic dogs in Romania remains to be confirmed by further studies.

Neonatal Anaplasma platys infection in puppies: Further evidence for possible vertical transmission

Anaplasma platys, the aetiological agent of infectious canine cyclic thrombocytopaenia, infects platelets of dogs, usually causing mild or asymptomatic disease. Although A. platys is transmitted by ticks, as for other Anaplasma species, alternative modes of transmission may be involved. The aim of the present study was to evaluate the occurrence of A. platys infection in litters of puppies, which could suggest possible vertical transmission. Twelve litters, together with the respective bitches, were included in the study for the detection of A. platys DNA by PCR, followed by sequencing. Five puppies, from 2/4 litters <28 days of age, tested positive for A. platys DNA. No puppies from eight litters 1-3 months of age tested positive for A. platys DNA. The identical sequences (16S rRNA and gltA partial gene), the absence of ticks on puppies at the time of collection and the young age of the five infected puppies suggest vertical transmission of A. platys. This mode of transmission might contribute to the maintenance and spread of the pathogen in canine populations.

Geographical distribution and prevalence of Borrelia burgdorferi genospecies in questing Ixodes ricinus from Romania: a countrywide study

The paper reports the prevalence and geographical distribution of Borrelia burgdorferi sensu lato (s.l.) and its genospecies in 12,221 questing Ixodes ricinus ticks collected at 183 locations from all the 41 counties of Romania. The unfed ticks were examined for the presence of B. burgdorferi s.l. by PCR targeting the intergenic spacer 5S-23S. Reverse line blot hybridization (RLB) and restriction fragment length polymorphism (RFLP) analysis were performed for identification of B. burgdorferi genospecies. The overall prevalence of infection was 1.4%, with an average local prevalence between 0.75% and 18.8%. B. burgdorferi s.l. was found in ticks of 55 of the 183 localities. The overall prevalence B. burgdorferi s.l. in ticks in the infected localities was 3.8%. The total infection prevalence was higher in female ticks than in other developmental stages. Three Borrelia genospecies were detected. The most widely distributed genospecies was B. afzelii, followed by B. garinii and B. burgdorferi sensu stricto (s.s.). The study is the first countrywide study and the first report of B. burgdorferi s.s. in Romania. The distribution maps show that higher prevalences were recorded in hilly areas, but Lyme borreliosis spirochetes were also present in forested lowlands, albeit with a lower prevalence.

Zoonotic pathogens associated with Hyalomma aegyptium in endangered tortoises: evidence for host-switching behaviour in ticks?

BACKGROUND

Hyalomma aegyptium is a hard-tick with a typical three-host life cycle. The main hosts are Palearctic tortoises of genus Testudo. However, other hosts can be used by immature ticks for feeding in natural conditions. Given this complex ecology and multiple host use, the circulation of pathogens by H. aegyptium between various hosts can be important from epidemiological point of view. The aim of this study was to evaluate the role of H. aegyptium as natural carrier of four important zoonotic pathogens.

METHODS

From 2008 to 2011, 448 H. aegyptium ticks were collected from 45 Spur-thighed tortoises, Testudo graeca in Romania. DNA was extracted individually from each tick using a commercial kit. DNA was examined for the presence of specific sequences of Borrelia burgdorferi s.l., Anaplasma phagocytophilum, Ehrlichia canis and Coxiella burnetii by PCR, according to previously described protocols.

RESULTS

PCR analysis of H. aegyptium revealed the presence of A. phagocytophilum (18.8%), E. canis (14.1%) and C. burnetii (10%). 32.4% of the ticks were infected with at least one pathogen and 9.8% had co-infections. The stages most frequently infected were nymphs (50%) followed by males (33.9%) and females (27%). The number of tortoises which harboured infected ticks was 27/45 examined (60%). From all tested T. graeca, 40% harboured ticks infected with A. phagocytophilum, 46.7% had ticks infected with E. canis and 33.3% had ticks with C. burnetii. This study reports for the first time the presence of A. phagocytophilum and E. canis in H. aegyptium.

CONCLUSIONS

The presence and relatively high prevalence of three important zoonotic pathogens in H. aegyptium raises the question of their epidemiologic importance in disease ecology. As tortoises are unlikely to be reservoir hosts for A. phagocytophilum and E. canis and both these pathogens are common in H. aegyptium, this is an important indication for (1) a possible increased host-switching behaviour of these ticks to competent reservoir hosts (i.e. hedgehogs) and (2) transstadial transmission. Furthermore, if we consider also the presence of C. burnetii, we conclude that T. graeca and its ticks should be evaluated more seriously when assessing the eco-epidemiology of zoonotic diseases.