Background Leishmania tarentolae is a protozoan isolated from geckoes (Tarentola annularis, Tarentola mauritanica), which is considered non-pathogenic and is transmitted by herpetophilic Sergentomyia spp. sand flies. This species occurs in sympatry with Leishmania infantum in areas where canine leishmaniasis is endemic. In the present study, we investigated the circulation of L. tarentolae and L. infantum in sand flies, dogs and lizards in a dog shelter in southern Italy, where canine leishmaniasis by L. infantum is endemic. Methods Sheltered dogs (n = 100) negative for Leishmania spp. (March 2020) were screened by immunofluorescence antibody test (IFAT) using promastigotes of both species at two time points (June 2020 and March 2021). Whole blood from dogs, tissues of Podarcis siculus lizards (n = 28) and sand flies (n = 2306) were also sampled and tested by a duplex real-time PCR (dqPCR). Host blood meal was assessed in sand flies by PCR. Results Overall, 16 dogs became positive for L. infantum and/or L. tarentolae by IFAT at one or both sampling periods. One canine blood sample was positive for L. infantum, whilst two for L. tarentolae by dqPCR. At the cytology of lizard blood, Leishmania spp. amastigote-like forms were detected in erythrocytes. Twenty-two tissue samples, mostly lung (21.4%), scored molecularly positive for L. tarentolae, corresponding to 10 lizards (i.e., 35.7%). Of the female Sergentomyia minuta sampled (n = 1252), 158 scored positive for L. tarentolae, four for L. infantum, and one co-infected. Two Phlebotomus perniciosus (out of 29 females) were positive for L. tarentolae. Engorged S. minuta (n = 10) fed on humans, and one P. perniciosus, positive for L. tarentolae, on lagomorphs. Conclusions Dogs and lacertid lizards (Podarcis siculus) were herein found for the first time infected by L. tarentolae. The detection of both L. tarentolae and L. infantum in S. minuta and P. perniciosus suggests their sympatric circulation, with a potential overlap in vertebrate hosts. The interactions between L. tarentolae and L. infantum should be further investigated in both vectors and vertebrate hosts to understand the potential implications for the diagnosis and control of canine leishmaniasis in endemic areas. Graphical abstract

We assessed the presence of Rickettsia spp., Coxiella burnetii and Anaplasma phagocytophilum in reptiles, their ectoparasites and in questing ticks collected in a nature preserve park in southern Italy, as well as in a peri-urban area in another region. We also investigated the exposure to these pathogens in forestry workers, farmers and livestock breeders living or working in the nature preserve park given the report of anecdotal cases of spotted fever rickettsioses. Rickettsia spp. were molecularly detected in Podarcis muralis and Podarcis siculus lizards (i.e., 3.1%), in Ixodes ricinus (up to 87.5%) and in Neotrombicula autumnalis (up to 8.3%) collected from them as well as in I. ricinus collected from the environment (up to 28.4%). Rickettsia monacensis was the most prevalent species followed by Rickettsia helvetica. An undescribed member of the family Anaplasmataceae was detected in 2.4% and 0.8% of the reptiles and ectoparasites, respectively. Sera from human subjects (n = 50) were serologically screened and antibodies to Rickettsia spp. (n = 4; 8%), C. burnetti (n = 8; 16%) and A. phagocytophilum (n = 11; 22%) were detected. Two ticks collected from two forestry workers were positive for spotted fever group (SFG) rickettsiae. Ixodes ricinus is involved in the transmission of SFG rickettsiae (R. monacensis and R. helvetica) in southern Europe and lizards could play a role in the sylvatic cycle of R. monacensis, as amplifying hosts. Meanwhile, N. autumnalis could be involved in the enzootic cycle of some SFG rickettsiae among these animals. People living or working in the southern Italian nature preserve park investigated are exposed to SFG rickettsiae, C. burnetii and A. phagocytophilum.

Background: Camel production in Saudi Arabia is severely affected by various diseases and by inadequate veterinary services. Ticks and tick-borne pathogens (TBPs) affect the health and wellbeing of camels consequently diminishing their productivity and performances. In addition, camels may act as hosts for TBPs (e.g. Anaplasma phagocytophilum) causing diseases in humans. The current study aimed to determine the prevalence of ixodid ticks and molecularly investigate the associated pathogens in camels from Saudi Arabia. Methods: Blood and tick samples were collected from camels (n = 170) in Riyad Province of Saudi Arabia. Ticks were morphologically identified, and blood of camels were molecularly screened for apicomplexan (i.e. Babesia spp., Theileria spp., Hepatozoon spp.) and rickettsial parasites (i.e. Ehrlichia spp. and Anaplasma spp.). Results: Of the 170 camels examined, 116 (68.2%; 95% CI: 60.9-75.1%) were infested by ticks with a mean intensity of 2.53 (95% CI: 2.4-2.6). In total of 296 ticks collected, Hyalomma dromedarii was the most prevalent (76.4%), followed by Hyalomma impeltatum (23.3%) and Hyalomma excavatum (0.3%). Of the tested animals, 13 (7.6%; 95% CI: 4.3-12.8%) scored positive to at least one TBP, with Anaplasma platys (5.3%; 95% CI: 2.7-9.9%) being the most prevalent species, followed by Anaplasma phagocytophilum, Anaplasma sp., Ehrlichia canis and Hepatozoon canis (0.6% each; 95% CI: 0.04-3.4%). None of the camels were found to be co-infected with more than one pathogen. All samples tested negative for Babesia spp. and Theileria spp. Conclusions: The present study reveals the occurrence of different tick species and TBPs in camels from Saudi Arabia. Importantly, these camels may carry A. phagocytophilum and A. platys, representing a potential risk to humans.

Tick-borne diseases (TBDs) are of increasing concern in public health worldwide (Otranto et al., 2015). Several sociodemographic factors, as agricultural strategies and wildlife management, deforestation and global warming are strongly involved in the alteration of ecosystems, affecting the tick-host interaction and the circulation of tick-borne pathogens (TBPs) (Dantas-Torres et al., 2013;Estrada-Peña & de la Fuente, 2014). Due to the restriction of natural habitats, urbanization may seriously change the composition of wildlife communities and their associated tick populations (Faeth et al., 2011). Human-induced environmental changes may inadvertently select for synanthropic wild mammals, driving the rise of emerging infectious diseases (EIDs) (McFarlane et al., 2012). In this scenario, wild boars (Sus scrofa) have increased in terms of density throughout Europe, with high occurrence in several countries, including Italy (Pittiglio et al., 2018). The abundance of this mammal may seriously contribute to the maintenance of ticks in the environment in urban and peri-urban areas (Rizzoli et al., 2014) leading to a high risk of human exposure to them and the pathogens they transmit (Pfäffle et al., 2013).

Background Wolbachia is an obligate intracellular maternally transmitted, gram-negative bacterium which forms a spectrum of endosymbiotic relationships from parasitism to obligatory mutualism in a wide range of arthropods and onchocercid nematodes, respectively. In arthropods Wolbachia produces reproductive manipulations such as male killing, feminization, parthenogenesis and cytoplasmic incompatibility for its propagation and provides an additional fitness benefit for the host to protect against pathogens, whilst in onchocercid nematodes, apart from the mutual metabolic dependence, this bacterium is involved in moulting, embryogenesis, growth and survival of the host. Methods This review details the molecular data of Wolbachia and its effect on host biology, immunity, ecology and evolution, reproduction, endosymbiont-based treatment and control strategies exploited for filariasis. Relevant peer-reviewed scientic papers available in various authenticated scientific data bases were considered while writing the review. Conclusions The information presented provides an overview on Wolbachia biology and its use in the control and/or treatment of vectors, onchocercid nematodes and viral diseases of medical and veterinary importance. This offers the development of new approaches for the control of a variety of vector-borne diseases. Graphic Abstract