Molecular evidence for Bartonella spp. in cat and dog fleas from Germany and France

Fleas from the Silk Road in Central Asia: identification of Ctenocephalides canis and Ctenocephalides orientis on owned dogs in Uzbekistan using molecular identification and geometric morphometrics

Background

The Silk Road connected the East and West for over 1500 years. Countries in Central Asia are valuable in addressing the hypothesis that parasites on domestic animals were introduced along the Silk Road. Adult fleas are obligate parasites, having worldwide distribution. In dogs, Ctenocephalides canis, C. felis and C. orientis are the most common species identified. The distribution of the Oriental cat flea, C. orientis, is restricted to southeast Asia. The purpose of this study was to determine the diversity of dog fleas from Uzbekistan, a country in Central Asia, with particular reference to C. orientis.

Methods

Fleas were collected from 77 dogs from 5 locations in Uzbekistan. The cox1 gene sequences from Ctenocephalides spp. were compared to global collection of Ctenocephalides cox1 haplotypes. Landmark-based geometric morphometrics have been applied to the head and curvature to compare C. canis and C. canis using canonical variate analysis and discriminant function analysis.

Results

Overall, 199 fleas were collected and identified as C. canis (n = 115, 58%), C. orientis (n = 53, 27%) and Pulex irritans (n = 22, 11%). None of the fleas were C. felis. All Ctenocephalides spp. fleas were subject to cox1 amplification and 95% (166/175) yielded DNA sequence. There were 25 cox1 haplotypes; 14 (22/25, 88%) were C. canis cox1 haplotypes and 3 (3/25, 12%) were C. orientis cox1 haplotypes. Molecular analysis confirmed the absence of C. felis. Four (4/22) and one (1/3) cox1 haplotypes were identical to cox1 haplotypes belonging to C. canis and C. orientis cox1 haplotypes identified elsewhere, respectively. Overall morphometric analysis confirmed significant differences between the head shape of C. canis and C. orientis and improved four–fivefold the species identification compared to traditional morphological key.

Conclusion

We report for the first time the presence of C. orientis in Uzbekistan. Differentiation of C. orientis from C. canis and C. felis remains difficult in regions where these species coexist. Studies in Central and Southeast Asia should confirm species identity using cox1 locus to enable retracing of the distribution of the Ctenocephalides in Asia. The presence of C. orientis suggests that this species may have been introduced from the east along the ancient Silk Road.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-022-05477-3.

Efficacy of a novel topical combination of esafoxolaner, eprinomectin and praziquantel against fleas in cats, under field conditions

Esafoxolaner is a purified afoxolaner enantiomer with insecticidal and acaricidal properties. It is combined with eprinomectin and praziquantel, nematodicidal and cestodicidal compounds, in a novel topical endectoparasiticide formulation for cats. This novel formulation was tested in four field studies, in the United States, Europe, Japan and Australia. In all studies, naturally flea-infested domestic cats were treated with the novel formulation at the label dose and conditions of use. The main objective, identical in the four studies, was to assess efficacy on fleas, based on comparison of mean number of fleas found on infested cats before and one month after treatment. Tolerance to the product was also evaluated in the four studies. Otherwise, the studies had some differences in their design and secondary objectives, for example testing for a reduction in flea infestation-related cutaneous signs, testing of one treatment or of three monthly treatments, and use of a positive control group. In the four studies, a total of 307 cats were treated with the novel formulation. The reduction of fleas one month after treatment was 97.7%, 98.8%, 100% and 99.7% in the United States, Europe, Japan and Australia, respectively. There were no significant health abnormalities attributed to treatment in any of the studies.

Efficacy of a novel topical combination of esafoxolaner, eprinomectin and praziquantel against adult cat flea Ctenocephalides felis and flea egg production in cats

Esafoxolaner, a purified enantiomer of afoxolaner with insecticidal and acaricidal properties, is combined with eprinomectin and praziquantel in NexGard® Combo, a novel topical endectoparasiticide formulation for cats. The efficacy of this novel formulation against adult and immature stages of Ctenocephalides felis fleas was tested in four experimental studies. Two studies were designed to test adulticide efficacy, one to test inhibition of immature stages, and one to test both adulticide efficacy and inhibition of immature stages. In each study, cats were randomly allocated to a placebo control group or to a novel formulation group treated once at the minimum recommended dose. Cats were experimentally infested weekly for one to two months with unfed C. felis originating from North America or Europe. For adulticide efficacy evaluations, live fleas were counted 24 h after treatment and after subsequent weekly infestations. For immature stages, flea eggs were collected and counted weekly for evaluation of egg production inhibition and incubated for larval hatching evaluation. In the three studies testing adult fleas, curative efficacies, 24 h after treatment, were 92.1%, 98.3% and 99.7%; preventive weekly efficacies, 24 h after weekly infestations, remained higher than 95.5% for at least one month. In the two studies testing immature stages, egg production and larval hatching was significantly reduced for at least one month. These studies provide robust evidence of efficacy of the novel formulation against experimental adult flea infestations and for the prevention of environmental contamination by immature flea stages, for at least one month.

The Discovery of Zoonotic Protozoans in Fleas Parasitizing on Pets as a Potential Infection Threat

PURPOSE

Fleas are insects with a high medical and veterinary importance. They may participate in spreading of many pathogenic agents, but still there is limited information about their possible reservoir or vector role for protozoans. The main aim of this study was an attempt of detection zoonotic pathogens, such as Babesia microti and Toxoplasma gondii in fleas Ctenocephalides felis felis and Ctenocephalides canis.

METHODS

In 2013-2017, 155 fleas were captured from domestic dogs and cats in veterinary clinics, animal shelters and pet grooming salons in Upper Silesia Region in Poland. Then, the DNA was extracted from each Ctenocephalides flea by using the ammonia method. Samples were screened for the presence of B. microti and T. gondii using PCR and nested PCR methods.

RESULTS

B. microti was reported in 6.6% of C. felis felis and 9.1% of C. canis, whereas the prevalence of coinfection with B. microti and T. gondii was 1.9% in cat fleas and 2.3% in dog fleas.

CONCLUSION

This study shows the first cases of B. microti occurrence and B. microti and T. gondii coinfection in Ctenocephalides fleas. The estimation of prevalence of examined protozoans may be useful considering the possibility of infection among companion animals, as well as during presentation of the potential risk of infection in humans. In order to clarify the role of C. felis felis and C. canis in transmission of B. microti and T. gondii, the another studies with in vitro cultures and laboratory animals are needed.

First molecular detection and characterization of zoonotic Bartonella species in fleas infesting domestic animals in Tunisia

Background

Bartonellosis is an emerging vector-borne disease caused by different intracellular bacteria of the genus Bartonella (Rhizobiales: Bartonellaceae) that is transmitted primarily by blood-sucking arthropods such as sandflies, ticks and fleas. In Tunisia, there are no data available identifying the vectors of Bartonella spp. In our research, we used molecular methods to detect and characterize Bartonella species circulating in fleas collected from domestic animals in several of the country’s bioclimatic areas.

Results

A total of 2178 fleas were collected from 5 cats, 27 dogs, 34 sheep, and 41 goats at 22 sites located in Tunisia’s five bioclimatic zones. The fleas were identified as: 1803 Ctenocephalides felis (83%) (Siphonaptera: Pulicidae), 266 C. canis (12%) and 109 Pulex irritans (5%) (Siphonaptera: Pulicidae). Using conventional PCR, we screened the fleas for the presence of Bartonella spp., targeting the citrate synthase gene (gltA). Bartonella DNA was detected in 14% (121/866) of the tested flea pools [estimated infection rate (EIR) per 2 specimens: 0.072, 95% confidence interval (CI): 0.060–0.086]. The Bartonella infection rate per pool was broken down as follows: 55% (65/118; EIR per 2 specimens: 0.329, 95% CI: 0.262–0.402) in C. canis; 23.5% (8/34; EIR per 2 specimens: 0.125, 95% CI: 0.055–0.233) in P. irritans and 6.7% (48/714; EIR per 2 specimens: 0.032, 95% CI: 0.025–0.045) in C. felis. Infection rates, which varied significantly by bioclimatic zone (P < 0.0001), were highest in the humid areas. By sequencing, targeting the gltA gene and the 16S–23S rRNA Intergenic Spacer Regions (ITS), we identified three Bartonella zoonotic species: B. elizabethae, B. henselae, B. clarridgeiae, as well as uncharacterized Bartonella genotypes.

Conclusions

To the best of our knowledge, this is the first time that fleas in Tunisia have been shown to carry zoonotic species of Bartonella. The dog flea, Ctenocephalides canis, should be considered the main potential vector of Bartonella. Our study not only provides new information about this vector, but also offers a public health update: medical practitioners and farmers in Tunisia should be apprised of the presence of Bartonella in fleas and implement preventive measures.

Electronic supplementary material

The online version of this article (10.1186/s13071-017-2372-5) contains supplementary material, which is available to authorized users.

Intestinal parasites and vector-borne pathogens in stray and free-roaming cats living in continental and insular Greece

This survey investigated the distribution of various intestinal parasites and vector-borne pathogens in stray and free-roaming cats living in four regions of Greece. A total number of one hundred and fifty cats living in three Islands (Crete, Mykonos and Skopelos) and in Athens municipality was established as a realistic aim to be accomplished in the study areas. All cats were examined with different microscopic, serological and molecular assays aiming at evaluating the occurrence of intestinal parasites, and exposure to or presence of vector-borne infections. A total of 135 cats (90%) was positive for one or more parasites and/or pathogens transmitted by ectoparasites. Forty-four (29.3%) cats were positive for one single infection, while 91 (60.7%) for more than one pathogen. A high number of (n. 53) multiple infections caused by feline intestinal and vector-borne agents including at least one zoonotic pathogen was detected. Among them, the most frequently recorded helminths were roundworms (Toxocara cati, 24%) and Dipylidium caninum (2%), while a high number of examined animals (58.8%) had seroreaction for Bartonella spp., followed by Rickettsia spp. (43.2%) and Leishmania infantum (6.1%). DNA-based assays revealed the zoonotic arthropod-borne organisms Bartonella henselae, Bartonella clarridgeiae, Rickettsia spp., and L. infantum. These results show that free-ranging cats living in areas of Greece under examination may be exposed to a plethora of internal parasites and vector-borne pathogens, some of them potentially able to infect humans. Therefore, epidemiological vigilance and appropriate control measures are crucial for the prevention and control of these infections and to minimize the risk of infection for people.

Several intestinal parasites and vector-borne pathogens, some of that with zoonotic potential, often occur in free-ranging cat populations. Stray cats are abundant in touristic areas of Greece, where they live in free colonies. With the aim to enhance our knowledge on the hazard posed by cats living in Greek touristic spots, the present research has evaluated the presence of intestinal parasites and vector-borne pathogens in stray cats living in selected areas. The study demonstrates that these pathogens are present in Greece and that appropriate control measures should be implemented to minimize the risk for cats and people.

Afoxolaner against fleas: immediate efficacy and resultant mortality after short exposure on dogs

The speed of efficacy of afoxolaner (NexGard) against Ctenocephalides felis fleas was evaluated in two studies. Study A assessed the efficacy against existing fleas whereas study B assessed the efficacy against new infesting fleas. In study A, 12 dogs were allocated to the untreated group and 20 dogs to the treated group. All dogs were infested by 100 fleas each at Day -1, treated at Day 0 and flea combed at 2 h or at 6 h post treatment. In study B, 6 dogs were allocated to the untreated group and 10 to the treated group. They were infested with 100 fleas each on Days 2, 7, 14, 21 and 28. Fleas were removed and counted at 6 h post-infestation. Immediate and persistent efficacies were evaluated by counting fleas on the dogs. To evaluate induced mortality after exposure on dogs, fleas collected alive were placed in an insectarium for 24 h and assessed for viability. The immediate efficacy on dogs was significant at 6 h with 100%. The induced death of the fleas collected live from dogs 2 h after exposure was 99.7%. Concerning new infesting fleas, the observed efficacy at 6 h and the induced mortality were significantly different (p < 0.05) from the control at all time-points. At 6 h, the prophylactic efficacy was > 97% at Day 2 and Day 8 and > 90% at Day 14. The induced mortality after 6 h of exposure on dogs varied between 73.3% and 100% for the whole study.

Fleas infesting pets in the era of emerging extra-intestinal nematodes

Modifications in climatic conditions, movements of hosts and goods, changes in animal phenology and human behaviour and increase of wildlife, are presently concurring in the geographic spread of vectors and cardio-respiratory nematodes, e.g. Dirofilaria immitis, Angiostrongylus vasorum, Aelurostrongylus abstrusus and Capillaria aerophila. All these factors may also influence dispersion and clinical significance of fleas, thus posing relevant challenges in those regions where other parasites are emerging at the same time. Ctenocephalides felis, Ctenocephalides canis and Pulex irritans cause discomfort, nuisance, allergic reactions, anaemia, and may transmit several pathogens, some of them are of importance for public health. The present article reviews the importance of fleas in small animal practice and their sanitary relevance for dogs, cats and humans, and discusses current control methods in the present era of emerging extra-intestinal nematodes, towards a possible changing perspective for controlling key parasites affecting companion animals.

Fleas as parasites of the family Canidae

Historically, flea-borne diseases are among the most important medical diseases of humans. Plague and murine typhus are known for centuries while the last years brought some new flea-transmitted pathogens, like R. felis and Bartonella henselae. Dogs may play an essential or an accidental role in the natural transmission cycle of flea-borne pathogens. They support the growth of some of the pathogens or they serve as transport vehicles for infected fleas between their natural reservoirs and humans. More than 15 different flea species have been described in domestic dogs thus far. Several other species have been found to be associated with wild canids. Fleas found on dogs originate from rodents, birds, insectivores and from other Carnivora. Dogs therefore may serve as ideal bridging hosts for the introduction of flea-borne diseases from nature to home. In addition to their role as ectoparasites they cause nuisance for humans and animals and may be the cause for severe allergic reactions.