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•Human tick-borne diseases are overwhelmingly zoonotic and involve an animal host.•Major tick-borne infections are typically caused by infringement of a circulation between wildlife ...reservoirs and tick vectors.•Emerging tick-borne infections circulated among wildlife animal and tick populations before being recognised as clinical causes of disease.•Co-infection with tick-borne agents that augment disease severity is related to infections in local wild life reservoirs.•Control programs for tick-borne diseases require integration of data from several scientific disciplines.
A wide variety of pathogens is transmitted from ticks to vertebrates including viruses, bacteria, protozoa and helminths, of which most have a life cycle that requires passage through the vertebrate host. Tick-borne infections of humans, farm and companion animals are essentially associated with wildlife animal reservoirs. While some flying insect-borne diseases of humans such as malaria, filariasis and Kala Azar caused by Leishmania donovani target people as their main host, major tick-borne infections of humans, although potentially causing disease in large numbers of individuals, are typically an infringement of a circulation between wildlife animal reservoirs and tick vectors. While new tick-borne infectious agents are frequently recognised, emerging agents of human tick-borne infections were probably circulating among wildlife animal and tick populations long before being recognised as clinical causes of human disease as has been shown for Borrelia burgdorferi sensu lato. Co-infection with more than one tick-borne infection is common and can enhance pathogenic processes and augment disease severity as found in B. burgdorferi and Anaplasma phagocytophilum co-infection. The role of wild animal reservoirs in co-infection of human hosts appears to be central, further linking human and animal tick-borne infections. Although transmission of most tick-borne infections is through the tick saliva, additional routes of transmission, shown mostly in animals, include infection by oral uptake of infected ticks, by carnivorism, animal bites and transplacentally. Additionally, artificial infection via blood transfusion is a growing threat in both human and veterinary medicine. Due to the close association between human and animal tick-borne infections, control programs for these diseases require integration of data from veterinary and human reporting systems, surveillance in wildlife and tick populations, and combined teams of experts from several scientific disciplines such as entomology, epidemiology, medicine, public health and veterinary medicine.
Two species of
Hepatozoon are currently known to infect dogs and cause distinct diseases.
Hepatozoon canis prevalent in Africa, Asia, southern Europe, South America and recently shown to be present ...also in the USA causes infection mainly of hemolymphoid organs, whereas
Hepatozoon americanum prevalent in the southeastern USA causes myositis and severe lameness.
H. americanum is transmitted by ingestion of the Gulf Coast tick
Amblyomma maculatum and also by predation on infected prey.
H. canis is transmitted by
Rhipicephalus sanguineus, in South America also by
Amblyomma ovale, and has also been shown to be transmitted transplacentally. Hepatozoonosis of domestic cats has been described mostly from the same areas where canine infection is present and the exact identity of the species which infect cats, their pathogenicity and vectors have not been elucidated. The diagnosis of hepatozoonosis is made by observation of gamonts in blood smears, histopathology, PCR or serology. The main treatment for
H. canis is with imidocarb dipropionate whereas
H. americanum infection is treated with an initial combination of trimethoprim–sulfadiazine, pyrimethamine and clindamycin followed by maintenance with decoquinate. Treatment for both diseases has not been reported to facilitate complete parasite elimination and new effective drugs are needed for the management of these infections. Prevention of hepatozoonosis should be based on avoidance of oral ingestion of infected tick vectors and infected prey.
Canine babesiosis caused by different
Babesia species is a protozoal tick-borne disease with worldwide distribution and global significance. Historically,
Babesia infection in dogs was identified ...based on the morphologic appearance of the parasite in the erythrocyte. All large forms of
Babesia were designated
Babesia canis, whereas all small forms of
Babesia were considered to be
Babesia gibsoni. However, the development of molecular methods has demonstrated that other
Babesia species such as
Babesia conradae,
Babesia microti like piroplasm,
Theileria spp. and a yet unnamed large form
Babesia spp. infect dogs and cause distinct diseases.
Babesia rossi,
B. canis and
Babesia vogeli previously considered as subspecies are identical morphologically but differ in the severity of clinical manifestations which they induce, their tick vectors, genetic characteristics, and geographic distributions, and are therefore currently considered separate species. The geographic distribution of the causative agent and thus the occurrence of babesiosis are largely dependent on the habitat of relevant tick vector species, with the exception of
B. gibsoni where evidence for dog to dog transmission indicates that infection can be transmitted among fighting dog breeds independently of the limitations of vector tick infestation. Knowledge of the prevalence and clinicopathological aspects of
Babesia species infecting dogs around the world is of epidemiologic and medical interest. Babesiosis in domestic cats is less common and has mostly been reported from South Africa where infection is mainly due to
Babesia felis, a small
Babesia that causes anemia and icterus. In addition,
Babesia cati was reported from India and sporadic cases of
B. canis infection in domestic cats have been reported in Europe,
B. canis presentii in Israel and
B. vogeli in Thailand. Babesiosis caused by large
Babesia spp. is commonly treated with imidocarb dipropionate with good clinical response while small
Babesia spp. are more resistant to anti-babesial therapy. Clinical and parasitological cure are often not achieved in the treatment of small
Babesia species infections and clinical relapses are frequent. The spectrum of
Babesia pathogens that infect dogs and cats is gradually being elucidated with the aid of molecular techniques and meticulous clinical investigation. Accurate detection and species recognition are important for the selection of the correct therapy and prediction of the course of disease.
Sheltered and stray dogs, exposed to zoonotic parasites, including protozoa, helminths, and arthropods, may represent a major threat to public health. Resources for addressing health problems in ...these animals are not on the priority list of veterinary and public health authorities. Thus, dogs continue to represent an important reservoir for zoonotic parasites. In this article, we review the importance of sheltered and stray dogs as reservoirs of zoonotic parasites in different parts of the world, especially in the context of the current global political and economic crisis.
Sheltered and stray dogs represent reservoirs of zoonotic parasites worldwide, especially in the context of the current global changes and economic crisis.
Stray dog populations are an underestimated problem in several countries, and management policies are virtually nonexistent, or not applied, particularly in developing nations.
Relocation of stray dogs from southern to northern countries of Europe has contributed to the establishment of parasites and/or their vectors in previously nonendemic areas.
Poverty and low public health standards may further worsen the welfare of dogs in developing and industrialized countries.
BACKGROUND: Theileria annae is a tick-transmitted small piroplasmid that infects dogs and foxes in North America and Europe. Due to disagreement on its placement in the Theileria or Babesia genera, ...several synonyms have been used for this parasite, including Babesia Spanish dog isolate, Babesia microti-like, Babesia (Theileria) annae, and Babesia cf. microti. Infections by this parasite cause anemia, thrombocytopenia, and azotemia in dogs but are mostly subclinical in red foxes (Vulpes vulpes). Furthermore, high infection rates have been detected among red fox populations in distant regions strongly suggesting that these canines act as the parasite’s natural host. This study aims to reassess and harmonize the phylogenetic placement and binomen of T. annae within the order Piroplasmida. METHODS: Four molecular phylogenetic trees were constructed using a maximum likelihood algorithm based on DNA alignments of: (i) near-complete 18S rRNA gene sequences (n = 76 and n = 93), (ii) near-complete and incomplete 18S rRNA gene sequences (n = 92), and (iii) tubulin-beta gene sequences (n = 32) from B. microti and B. microti-related parasites including those detected in dogs and foxes. RESULTS: All phylogenetic trees demonstrate that T. annae and its synonyms are not Theileria parasites but are most closely related with B. microti. The phylogenetic tree based on the 18S rRNA gene forms two separate branches with high bootstrap value, of which one branch corresponds to Babesia species infecting rodents, humans, and macaques, while the other corresponds to species exclusively infecting carnivores. Within the carnivore group, T. annae and its synonyms from distant regions segregate into a single clade with a highly significant bootstrap value corroborating their separate species identity. CONCLUSION: Phylogenetic analysis clearly shows that T. annae and its synonyms do not pertain to Theileria and can be clearly defined as a separate species. Based on the facts that T. annae and its synonyms have not been shown to have a leukocyte stage, as expected in Theileria, do not infect humans and rodents as B. microti, and cluster phylogenetically as a separate species, this study proposes to name this parasite Babesia vulpes sp. nov., after its natural host, the red fox V. vulpes.
Spirocerca vulpis
is a parasitic nematode of red foxes associated with gastric nodule formation. Since its description in 2018, this species has been reported in red foxes from Spain, Bosnia and ...Herzegovina, Italy, and Portugal. We present here the analysis of uncharacterized nematodes obtained from gastric nodules of a red fox from Switzerland in 1999. The specimens were identified as
S. vulpis
based on the observation of teeth-like structures in the buccal capsule and a 99.4% sequence identity to
S. vulpis
DNA from Spain. Phylogenetic analysis demonstrated the clustering of the Swiss sequences in a different group from specimens of other geographical locations. Altogether, this study constitutes the first report of
S. vulpis
in Switzerland and a report of the oldest specimen of this species in the world. Our findings highlight the widespread distribution of
S. vulpis
in Europe which may be facilitated by the free-roaming nature of red foxes.
Canine babesiosis is a tick-borne disease caused by several Babesia spp. which have different susceptebility to anti-protozoal drugs. A few drugs and drug combinations are used in the treatment of ...canine babesiosis often without complete parasite elimination leaving treated dogs as carriers which could relapse with clinical disease and also transmit infection further. Although the large form canine babesial species Babesia canis, Babesia vogeli and Babesia rossi are sensitive to the aromatic diamidines imidocarb dipropionate and diminazene aceturate, small form species such as Babesia gibsoni, Babesia conradae and Babesia vulpes (Theileria annae) are relatively resistant to these drugs and are treated with the combination of the hydroxynaphthoquinone atovaquone and the antibiotic azithromycin. Azithromycin and other antibiotics that have anti-protozoal properties target the apicoplast, a relict plastid found in protozoa, and exert a delayed death effect. The triple combination of clindamycin, diminazene aceturate and imidocarb dipropionate is also effective against B. gibsoni and used to treat atovaquone-resistant strains of this species. Novel drugs and the synergistic effects of drug combinations against Babesia infection should be explored further to find new treatments for canine babesiosis.
Background
Accurate diagnosis is imperative in dogs with clinical signs of parvovirus infection (CPV‐2).
Objectives
To assess quantitative real‐time PCR (qRT‐PCR) for the diagnosis of CPV‐2 ...infection, and determine the optimal sampling site. Secondarily, to compare qRT‐PCR with a point‐of‐care PCR kit (PCRun), and to assess sensitivity of serology for CPV diagnosis.
Animals
Sixty dogs with naturally acquired parvovirus infection, 44 unvaccinated puppies, of which 16 were followed after first and second vaccination, 15 adult dogs, of which 10 were followed also after a booster vaccine, and 9 dogs with distemper virus infection.
Methods
Prospective study. Samples from the rectum, blood, and pharynx were obtained for PCR.
Results
All dogs with a clinical diagnosis of parvovirus infection were positive by qRT‐PCR in at least 1 sampling site (ie, rectum, blood, pharynx), and 50 (83%) of 60 were positive in all sites. qRT‐PCR was negative in 67 (99%) of 68 healthy puppies (before‐vaccination), puppies with distemper, and healthy adult dogs. Ten days after initial vaccination of puppies, 62% (fecal), 31% (blood), and 12% (pharyngeal) of samples were positive for CPV‐2 on qRT‐PCR. The proportion of positive pharyngeal samples decreased 20 days after vaccination and all sites were negative 12‐28 days after second vaccination. Vaccinated adults were negative before and after booster vaccination.
Conclusions and Clinical Importance
Molecular detection of CPV is sensitive, but specificity is hampered temporarily during the vaccination period. Blood, feces, and pharynx are suitable sampling sites. Fecal samples had the lowest sensitivity in sick dogs and highest positivity in puppies after vaccination.
Recent research has provided new insights on the epidemiology, pathology and immunology of canine leishmaniosis (CanL) and its genetic basis. The prevalence of infection in endemic areas is ...considerably higher than that of apparent clinical illness. In addition, infection spreads rapidly among dogs in the presence of optimal conditions for transmission. Infection involves a variety of granulomatous and harmful immune-mediated responses, and susceptibility to the disease is influenced by a complex genetic basis. These concepts will be instrumental for devising control programs. This review, the first in a series of two articles on CanL, presents an updated view on progress in elucidating the epidemiology and pathogenesis of this challenging disease, and the second part focuses on advances in diagnosis, treatment and prevention.
Dirofilaria repens is a nematode affecting domestic and wild canids, transmitted by several species of mosquitoes. It usually causes a non-pathogenic subcutaneous infection in dogs and is the ...principal agent of human dirofilariosis in the Old World. In the last decades, D. repens has increased in prevalence in areas where it has already been reported and its distribution range has expanded into new areas of Europe, representing a paradigmatic example of an emergent pathogen. Despite its emergence and zoonotic impact, D. repens has received less attention by scientists compared to Dirofilaria immitis. In this review we report the recent advances of D. repens infection in dogs and humans, and transmission by vectors, and discuss possible factors that influence the spread and increase of this zoonotic parasite in Europe. There is evidence that D. repens has spread faster than D. immitis from the endemic areas of southern Europe to northern Europe. Climate change affecting mosquito vectors and the facilitation of pet travel seem to have contributed to this expansion; however, in the authors' opinion, the major factor is likely the rate of undiagnosed dogs continuing to perpetuate the life-cycle of D. repens. Many infected dogs remain undetected due to the subclinical nature of the disease, the lack of rapid and reliable diagnostic tools and the poor knowledge and still low awareness of D. repens in non-endemic areas. Improved diagnostic tools are warranted to bring D. repens diagnosis to the state of D. immitis diagnosis, as well as improved screening of imported dogs and promotion of preventative measures among veterinarians and dog owners. For vector-borne diseases involving pets, veterinarians play a significant role in prevention and should be more aware of their responsibility in reducing the impact of the zoonotic agents. In addition, they should enhance multisectorial collaboration with medical entomologists and the public health experts, under the concept and the actions of One Health-One Medicine.
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