The cat flea (Ctenocephalides f. felis) is the dominant flea on domestic dogs and cats in Australian veterinary practices

Epidemiological exploration of fleas and molecular identification of flea-borne viruses in Egyptian small ruminants

The study aimed to investigate molecularly the presence of flea-borne viruses in infested small ruminants with fleas. It was carried out in Egypt's Northern West Coast (NWC) and South Sinai Governorate (SSG). Three specific primers were used targeting genes, ORF103 (for Capripoxvirus and Lumpy skin disease virus), NS3 (for Bluetongue virus), and Rdrp (for Coronavirus), followed by gene sequencing and phylogenetic analyses. The results revealed that 78.94% of sheep and 65.63% of goats were infested in the NWC area, whereas 49.76% of sheep and 77.8% of goats were infested in the SSG region. Sheep were preferable hosts for flea infestations (58.9%) to goats (41.1%) in the two studied areas. Sex and age of the animals had no effects on the infestation rate (p > 0.05). The season and site of infestation on animals were significantly different between the two areas (p < 0.05). Ctenocephalides felis predominated in NWC and Ctenocephalides canis in SSG, and males of both flea species were more prevalent than females. Molecular analysis of flea DNA revealed the presence of Capripoxvirus in all tested samples, while other viral infections were absent. Gene sequencing identified three isolates as sheeppox viruses, and one as goatpox virus. The findings suggest that Capripoxvirus is adapted to fleas and may be transmitted to animals through infestation. This underscores the need for ongoing surveillance of other pathogens in different regions of Egypt.

Molecular detection of Rickettsia sp. genotype RF2125 from household dogs in the central highlands of Vietnam

Rickettsia felis, a zoonotic vector-borne bacteria, is reported globally in humans, animals, and its invertebrate hosts. This study was designed to detect antibodies against R. felis and the DNA of R. felis in blood of domestic dogs in the Central Highlands of Vietnam using immunofluorescence antibody test (IFAT), and ompB- and gltA-PCRs, respectively. Using IFAT, 23 out of 338 plasma samples collected from household dogs were seropositive for R. felis, accounting for 6.80% (CI 95%: 4.45-10.1%). Of 171 buffy coat samples from household dogs, 50 were positive for spotted fever group rickettsioses using ompB-PCR assay, accounting for 29.2% (CI 95%: 22.6-36.7%). The gltA-PCR assay detected R. felis in 30% (15/50) of ompB-positive samples. DNA sequencing of ompB-PCR and gltA-PCR products confirmed the presence of R. felis and Rickettsia sp. genotype RF2125 / R. asembonensis. Our findings suggest a potential risk of R. felis infection in the communities in the Central Highlands of Vietnam, and the reservoir role of dogs to Rickettsia sp. genotype RF2125.

Epidemiological Study of the Occurrence of Typhus Group Rickettsia Natural Infection in Domiciliated Dogs from a Rural Community in South-Eastern Mexico

Simple Summary

Rickettsioses are relevant emergent and reemergent zoonoses in the Americas, including Mexico. Murine typhus caused by typhus group (TG) Rickettsia is prevalent in humans and their companion animals, such as dogs. This study found that 23.9% of the dogs (34/142) were infected by TG Rickettsia in Maxcanú, Yucatan (southeastern Mexico). Statistical analyses showed that reduced outdoor activities, age, sex and previous antiparasitic treatment are associated factors with less risk of TG Rickettsia infection in the sampled dogs. Monitoring and controlling these factors could help to restrict the enzootic transmission risk and prevent the potential zoonotic transmission.

Abstract

The aim is to describe the Typhus group (TG) Rickettsia infection in dogs and to identify factors associated with this infection. We collected blood samples and gathered exposure and clinical data of 142 dogs from a rural community of Yucatan. The Rickettsia group was determined by semi-nested PCR. Generalized linear models with binomial error distribution were used to model the associated factors from the dog sample for risk ratio (RR) estimation. Thirty-four dogs (23.9%) showed molecular evidence of TG Rickettsia DNA. The multivariate model showed that mixed-breed dogs (RR = 0.06) and dogs that had received antiparasitic treatment (RR = 0.049) had a lower risk of getting infected, taking as reference the purebred group and the non-treated dogs, respectively. Looking at variable interactions, adult dogs without outdoor activities had a lower infection risk than puppies (RR = 0.26). Among dogs with antiparasitic treatment, females had a higher infection risk than male dogs (RR = 26.2). The results showed enzootic TG Rickettsia circulation in dogs of a rural community. The factors outdoor activities, age and previous antiparasitic treatment, as well as the clinical variables signs of hemorrhages and epistaxis, were associated with a less chance of natural infection in the studied dogs. Prevention and control of the enzootic transmission risk of TG Rickettsia should help to reduce the potential zoonotic transmission of this pathogen.

Population genetics and genetic variation of Ctenocephalides felis and Pulex irritans in China by analysis of nuclear and mitochondrial genes

Background

Fleas are the most economically significant blood-feeding ectoparasites worldwide. Ctenocephalides felis and Pulex irritans can parasitize various animals closely related to humans and are of high veterinary significance.

Methods

In this study, 82 samples were collected from 7 provinces of China. Through studying the nuclear genes ITS1 and EF-1α and two different mitochondrial genes cox1 and cox2, the population genetics and genetic variation of C. felis and P. irritans in China were further investigated.

Results

The intraspecies differences between C. felis and P. irritans ranged from 0 to 3.9%. The interspecific variance in the EF-1α, cox1, and cox2 sequences was 8.2–18.3%, while the ITS1 sequence was 50.1–52.2%. High genetic diversity was observed in both C. felis and P. irritans, and the nucleotide diversity of cox1 was higher than that of cox2. Moderate gene flow was detected in the C. felis and P. irritans populations. Both species possessed many haplotypes, but the haplotype distribution was uneven. Fu's Fs and Tajima's D tests showed that C. felis and P. irritans experienced a bottleneck effect in Guangxi Zhuang Autonomous Region and Henan province. Evolutionary analysis suggested that C. felis may have two geographical lineages in China, while no multiple lineages of P.irritans were found.

Conclusions

Using sequence comparison and the construction of phylogenetic trees, we found a moderate amount of gene flow in the C. felis and P. irritans populations. Both species possessed many haplotypes, but the distribution of haplotypes varied among the provinces. Fu’s Fs and Tajima’s D tests indicated that both species had experienced a bottleneck effect in Guangxi and Henan provinces. Evolutionary analysis suggested that C. felis may have two geographical lineages in China, while no multiple lineages of P.irritans were found. This study will help better understand fleas' population genetics and evolutionary biology.

Graphical Abstract

Cat fleas (Ctenocephalides felis clade 'Sydney') are dominant fleas on dogs and cats in New South Wales, Australia: Presence of flea-borne Rickettsia felis, Bartonella spp. but absence of Coxiella burnetii DNA

The cat flea (Ctenocephalides felis) is the most common flea species parasitising both domestic cats and dogs globally. Fleas are known vectors of zoonotic pathogens such as vector-borne Rickettsia spp. and Bartonella spp. and could theoretically transmit Coxiella burnetii, the causative agent of Q fever. A total of 107 fleas were collected from 21 cats and 14 dogs in veterinary clinics, a feline rescue organisation and a grooming salon in New South Wales, Australia, to undergo PCR detection of Bartonella spp., Rickettsia spp. and C. burnetii DNA. Morphological identification confirmed that the cat flea (C. felis) is the most common flea in New South Wales, Australia, with only a single stick fast flea, Echidnophaga gallinacea recorded. The examined fleas (n = 35) at the cox1 locus revealed five closely related C. felis haplotypes (inter-haplotype distance < 0.5%). Multiplex TaqMan qPCR targeting the gltA (Rickettsia spp.) and ssrA (Bartonella spp.) genes was positive in 22.9% (95% CI: 11.8–39.3%) and 11.4% (95% CI: 3.9–26.6%) of samples, respectively. None of the DNA isolated from fleas was positive on TaqMan qPCRs targeting the C. burnetii IS1111, Com1 and htpAB genes. Co-infection of C. felis with Bartonella henselae and Bartonella clarridgeiae was demonstrated using gltA and ssrA Illumina next-generation amplicon sequencing. These findings reinforce the importance of flea control on domestic dogs and cats to effectively control the transmission of Rickettsia felis and Bartonella spp. The flea, however, is unlikely to be a vector of C. burnetii between companion animals and humans.

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The cat flea (Ctenocephalides felis) is the flea species on cats and dogs in New South Wales Australia.

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Absence of Coxiella burnetii DNA in flea extract, but presence of Rickettsia felis.

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Detection of Bartonella DNA using gltA and ssrA Illumina next-generation amplicon sequencing.

Ectoparasites infesting animals living in close contact with human beings: a real trouble for One Health perspective?

ABSTRACT The number of domestic animals living with human beings is rapidly increasing in parallel with an enhanced risk of transmission of their parasites and the pathogens they might carry. The aim of this study was to assess the occurrence of hematophagous arthropods infesting domestic animals from Northeastern Brazil and to remark the implications of their occurrence on the epidemiology and control of selected veterinary and human diseases. From January 2017 to April 2019, ectoparasites infesting domestic cats, dogs and horses were collected for their respective hosts and identified. Overall, ectoparasites were sampled from 86 domestic animals, living in different anthropic settings. A total of 401 specimens (344 ticks and 57 fleas) were collected from different hosts [i.e., 10 (2.49%), 96 (23.94%) and 295 (73.57%) from cats, dogs and horses, respectively]. Two flea (i.e., Ctenocephalides canis and Ctenocephalides felis) and 5 tick species (i.e., Amblyomma ovale, Amblyomma sculptum, Dermacentor nitens, Rhipicephalus microplus and Rhipicephalus sanguineus sensu lato) were identified. This study provides data on the ectoparasite fauna infesting domestic animals from Northeastern Brazil. The diagnosis and treatment of these parasites should not be underestimated, considering the role that hematophagous arthropods display as vectors of pathogens of medical and veterinary concern.

The molecular identity of fleas (Siphonaptera) carrying Rickettsia felis, Bartonella clarridgeiae and Bartonella rochalimae from dogs and cats in Northern Laos

Cat fleas (Ctenocephalides felis) are the most commonly recognised ectoparasites of domestic pets globally and are frequently implicated in the transmission of a variety of zoonotic vector-borne pathogens. The aim of the present study was to investigate the morphological and molecular identity of fleas parasitising cats and dogs in Northern Laos and screen them for a range of bacterial pathogens. Fleas (n = 120) were collected from dogs and cats and morphologically identified as Ctenocephalides felis (115/120), Ctenocephalides orientis (4/120) and Pulex irritans (1/120). Molecular barcoding using the cytochrome c oxidase subunit I gene (cox1) was used to confirmed species identity of 21 selected fleas. The cat flea (C. felis) was the most dominant flea identified. Rickettsia and Bartonella spp. DNA was detected in 21/21 and 7/21 samples, respectively, via a multiplex real-time PCR targeting gltA and ssrA. Sequencing of the seven Bartonella-positive samples and ten Rickettsia-positive samples revealed Bartonella clarridgeiae, Bartonella rochalimae, Rickettsia felis and Rickettsia sp. genotype RF2125 DNA. Anaplasma platys DNA was detected in a single C. felis after 20 of the 21 DNA samples were screened using a commercial PCR panel for vector-borne pathogens. The detection of a range of bacterial pathogens in fleas from owned cats and dogs in Northern Laos provides further evidence to the importance of these ectoparasites as vectors of zoonotic diseases in the region.

Safety and efficacy of a new spot-on formulation of selamectin plus sarolaner in the treatment and control of naturally occurring flea infestations in cats presented as veterinary patients in Australia

Background

The safety and efficacy of a new spot-on formulation of selamectin plus sarolaner were evaluated for the treatment and control of natural flea infestations on cats in two non-randomised, multi-centre clinical trials conducted in 8 different locations in Queensland, Australia.

Methods

One hundred and four cats from 65 different households were enrolled across the two studies. Demographic characteristics of cats in the two studies were similar. The new spot-on formulation of selamectin and sarolaner was administered topically once a month for 3 consecutive months at a minimum dosage of 6 mg/kg selamectin (dose range 6–12 mg/kg) plus 1 mg/kg sarolaner (dose range 1–2 mg/kg). Cats were dosed on Days 0 (pre-treatment), 30 and 60 and physical examinations and flea counts were conducted on Days 0, 30, 60 and 90. Efficacy assessments were based on the percentage reduction in live flea counts post-treatment compared to Day 0.

Results

In Study A, at enrolment, primary cats had flea counts ranging from 6 to 107 (arithmetic mean 21.0). The selamectin and sarolaner spot-on formulation resulted in arithmetic mean efficacy of 98.0%, 100% and 100% on Days 30, 60 and 90, respectively. In Study B, at enrolment, primary cats had flea counts ranging from 6 to 22 (arithmetic mean 10.0). The selamectin and sarolaner spot-on formulation resulted in arithmetic mean efficacy of 99.7%, 100% and 100% on Days 30, 60 and 90, respectively.

Conclusions

The new spot-on formulation of selamectin plus sarolaner topically administered at monthly intervals at the minimum dosage of 6.0 mg/kg selamectin and 1.0 mg/kg sarolaner was safe and highly effective against natural infestations of fleas under a range of geographical conditions, representative of both tropical and subtropical regions of Australia.

New insights into the haplotype diversity of the cosmopolitan cat flea Ctenocephalides felis (Siphonaptera: Pulicidae)

The present study investigated the genetic profile of the cosmopolitan cat flea, Ctenocephalides felis (Siphonaptera: Pulicidae) from Malaysia and the reference data available in the National Center for Biotechnology Information (NCBI) GenBank. A set of sequences of 100 Malaysian samples aligned as 550 characters of the cytochrome c oxidase subunit I (cox1) and 706 characters of the II (cox2) genes revealed ten haplotypes (A1-A10) and eight haplotypes (B1-B8), respectively. The concatenated sequences of cox1 and cox2 genes with a total of 1256 characters revealed 15 haplotypes (AB1-AB15). Analyses indicated that haplotype AB1 was the most frequent and the most widespread haplotype in Malaysia. Overall haplotype and nucleotide diversities of the concatenated sequences were 0.52909 and 0.00424, respectively, with moderate genetic differentiation (F_ST = 0.17522) and high gene flow (N_m = 1.18). The western population presented the highest genetic diversity (H_d = 0.78333, P_i = 0.01269, N_h = 9), whereas the southern population demonstrated the lowest diversity (H_d = 0.15667, P_i = 0.00019, N_h = 3). The concatenated sequences showed genetic distances ranged from 0.08 % to 4.39 %. There were three aberrant haplotypes in cox2 sequences that highly divergent, suggesting the presence of cryptic species or occurrence of introgression. In the global point of view, the aligned sequences of C. felis revealed 65 haplotypes (AA1-AA65) by the cox1 gene (n = 586), and 27 haplotypes (BB1-BB27) by the cox2 gene (n = 204). Mapping of the haplotype network showed that Malaysian C. felis possesses seven unique haplotypes in both genes with the common haplotypes demonstrated genetic affinity with C. felis from Southeast Asia for cox1 and South America for cox2. The topologies of cox1 and cox2 phylogenetic trees were concordant with relevant grouping pattern of haplotypes in the network but revealed two major lineages by which Malaysian haplotypes were closely related with haplotypes from the tropical region.

Ctenocephalides felis (cat flea) infestation in neonatal dairy calves managed with deltamethrin pour-on in Australia

Ctenocephalides felis infestations outbreak is documented as a welfare and production limiting disease in neonatal calves in eastern New South Wales, Australia. Due to the calves' discomfort, the first objective was to relieve the calves from the large burden of fleas. The affected neonatal 0-4 week old calves showed dull and quiet demeanour, with the geometric mean of body condition score (BCS) 2.67 (2-4) and geometric mean burden 41.51 (15-75) of fleas collected over 3 min. Deltamethrin pour-on (Arrest Easy-Dose, Virbac Animal Health, Australia) registered for treatment of lice and flies on cattle in Australia was evaluated for control effect of the cat flea (C. felis) on cattle. The fleas were identified morphologically as being C. felis which was confirmed by sequencing cytochrome c oxidase I gene (cox1). We report successful improvement of welfare and reduction of flea counts post application of pour-on deltamethrin on the property. In the absence of registered flea product for cattle in Australia, deltamethrin pour-on product is a suitable option, because of its registration for control of lice and flies on cattle.

Climate change models predict southerly shift of the cat flea (Ctenocephalides felis) distribution in Australia

BACKGROUND

Bioclimatic variables play an integral part in the life-cycle of Ctenocephalides felis, the most common flea found on companion animals. It is essential that we understand the effects of climate on C. felis distribution as fleas are a major veterinary and public health concern. This study investigated the current distribution of C. felis in Australia and future projections based on climate modelling.

RESULTS

Typing of C. felis was undertaken using the cytochrome c oxidase subunit 1 (cox1) mitochondrial DNA (mtDNA) region and current distribution of haplotypes was mapped by Maximum Entropy (Maxent) niche modelling. All C. felis haplotypes have been predicted to persist in environments along the eastern and southern coastlines of Australia and distinct ecological niches were observed for two C. felis haplogroups. Clade 'Cairns' haplogroup thrives under the northern coastal tropical conditions whilst Clade 'Sydney' haplogroup persists in temperate climates along the eastern and southern coasts. The model was then used to predict areas that are projected to have suitable climatic conditions for these haplogroups in 2050 and 2070 under the Intergovernmental Panel on Climate Change (IPCC) climate change scenarios. Under all IPCC Representative Concentration Pathways (RCP) climate change scenarios, the geographical range of all haplotypes was reduced by 5.59-42.21% in 2050 and 27.08-58.82% by 2070. The ranges of all clades were predicted to shift south along the eastern coastline.

CONCLUSIONS

As future temperatures exceed critical threshold temperatures for C. felis development in the northern tropical areas, Clade 'Cairns' haplogroup is predicted to shift south along the coastline and possibly outcompete the temperate haplogroup in these areas. If C. felis haplogroups possess distinct climatic niches it suggests a potential for these to be biologically distinct and have differing developmental rates and vector capabilities.

Out-of-Africa, human-mediated dispersal of the common cat flea, Ctenocephalides felis: The hitchhiker's guide to world domination

The cat flea (Ctenocephalides felis) is the most common parasite of domestic cats and dogs worldwide. Due to the morphological ambiguity of C. felis and a lack of - particularly largescale - phylogenetic data, we do not know whether global C. felis populations are morphologically and genetically conserved, or whether human-mediated migration of domestic cats and dogs has resulted in homogenous global populations. To determine the ancestral origin of the species and to understand the level of global pervasion of the cat flea and related taxa, our study aimed to document the distribution and phylogenetic relationships of Ctenocephalides fleas found on cats and dogs worldwide. We investigated the potential drivers behind the establishment of regional cat flea populations using a global collection of fleas from cats and dogs across six continents. We morphologically and molecularly evaluated six out of the 14 known taxa comprising genus Ctenocephalides, including the four original C. felis subspecies (Ctenocephalides felis felis, Ctenocephalides felis strongylus, Ctenocephalides felis orientis and Ctenocephalides felis damarensis), the cosmopolitan species Ctenocephalides canis and the African species Ctenocephalides connatus. We confirm the ubiquity of the cat flea, representing 85% of all fleas collected (4357/5123). Using a multigene approach combining two mitochondrial (cox1 and cox2) and two nuclear (Histone H3 and EF-1α) gene markers, as well as a cox1 survey of 516 fleas across 56 countries, we demonstrate out-of-Africa origins for the genus Ctenocephalides and high levels of genetic diversity within C. felis. We define four bioclimatically limited C. felis clusters (Temperate, Tropical I, Tropical II and African) using maximum entropy modelling. This study defines the global distribution, African origin and phylogenetic relationships of global Ctenocephalides fleas, whilst resolving the taxonomy of the C. felis subspecies and related taxa. We show that humans have inadvertently precipitated the expansion of C. felis throughout the world, promoting diverse population structure and bioclimatic plasticity. By demonstrating the link between the global cat flea communities and their affinity for specific bioclimatic niches, we reveal the drivers behind the establishment and success of the cat flea as a global parasite.

Ectoparasites infesting dogs and cats in Bishoftu, central Oromia, Ethiopia

A total of 200 dogs and 137 cats were examined for the presence of fleas, ticks and lice in Bishoftu, central Oromia, Ethiopia from September 2009 through April 2010. At least one ectoparasite species was found on 97% (194/200) of the dogs and 90.5% (124/137) of the cats. On dogs, fleas (Ctenocephalides felis (95%), Pulex irritans (20.5%), Echidnophaga gallinacea (9%) and Xenopsylla cheopis (0.5%)), ticks (Haemaphysalis leachi (17.5%), Amblyomma variegatum (8.5%), Rhipicephalus sanguineus (8%), Rhipicephalus pulchellus (5.5%) and Rhipicephalus (Boophilus) decoloratus (2.5%)) and lice (Heterodoxus spiniger (5%), Linognathus setosus (1.5%) and Trichodectes canis (0.5%)) were identified. On cats, fleas (C. felis (61.7%), E. gallinacea (24.1%), P. irritans (1.5%) and X. cheopis (0.7%)) and ticks (Ha. leachi (10.9%), Am. variegatum (1.5%) and Rh. sanguineus (0.7%)) were identified. C. felis was identified as the predominant ectoparasite on both dogs and cats. The overall frequency and count of ectoparasites was higher on dogs than on cats. Significantly higher overall frequency of fleas on young versus adult cats (p = .01) was recorded. However, ticks were significantly higher on adult cats than on young cats (p = .01). In conclusion, this study demonstrated great species diversity and high frequency of ectoparasites on dogs and cats in the study area. Further studies are required to investigate the role of these ectoparasites in transmission of zoonotic pathogens to humans and animals in Ethiopia.

Parasite spread at the domestic animal - wildlife interface: anthropogenic habitat use, phylogeny and body mass drive risk of cat and dog flea (Ctenocephalides spp.) infestation in wild mammals

BACKGROUND

Spillover of parasites at the domestic animal - wildlife interface is a pervasive threat to animal health. Cat and dog fleas (Ctenocephalides felis and C. canis) are among the world's most invasive and economically important ectoparasites. Although both species are presumed to infest a diversity of host species across the globe, knowledge on their distributions in wildlife is poor. We built a global dataset of wild mammal host associations for cat and dog fleas, and used Bayesian hierarchical models to identify traits that predict wildlife infestation probability. We complemented this by calculating functional-phylogenetic host specificity to assess whether fleas are restricted to hosts with similar evolutionary histories, diet or habitat niches.

RESULTS

Over 130 wildlife species have been found to harbour cat fleas, representing nearly 20% of all mammal species sampled for fleas. Phylogenetic models indicate cat fleas are capable of infesting a broad diversity of wild mammal species through ecological fitting. Those that use anthropogenic habitats are at highest risk. Dog fleas, by contrast, have been recorded in 31 mammal species that are primarily restricted to certain phylogenetic clades, including canids, felids and murids. Both flea species are commonly reported infesting mammals that are feral (free-roaming cats and dogs) or introduced (red foxes, black rats and brown rats), suggesting the breakdown of barriers between wildlife and invasive reservoir species will increase spillover at the domestic animal - wildlife interface.

CONCLUSIONS

Our empirical evidence shows that cat fleas are incredibly host-generalist, likely exhibiting a host range that is among the broadest of all ectoparasites. Reducing wild species' contact rates with domestic animals across natural and anthropogenic habitats, together with mitigating impacts of invasive reservoir hosts, will be crucial for reducing invasive flea infestations in wild mammals.

Urban environments alter parasite fauna, weight and reproductive activity in the quenda (Isoodon obesulus)

Some wildlife species are capable of surviving in urbanised environments. However, the implications of urbanisation on wildlife health, and public health regarding zoonoses, are often unknown. Quenda (syn. southern brown bandicoots, Isoodon obesulus) survive in many areas of Perth, Australia, despite urbanisation. This study investigated differences in gastrointestinal and macroscopic ecto-parasitic infections, morphometrics and reproductive status between bushland and urban dwelling quenda. 287 quenda in the greater Perth region were captured and sampled for faeces (to detect gastrointestinal parasites), blood (to detect Toxoplasma gondii antibodies), ectoparasites, and morphometrics. Data were analysed using multivariable logistic and linear regression. Most parasitic infections identified in quenda were of native parasite taxa that are either not known to, or considered highly unlikely to, infect humans or domestic animals. However, stickfast fleas (Echidnophaga spp.) were present at low prevalences and intensities, and Giardia spp., Cryptosporidium spp. and Amblyomma spp. infections require further investigation to clarify their anthropozoonotic significance. Quenda captured in urbanised environments had differing odds of or intensity of certain parasitic infections, compared to those in bushland - likely attributable to quenda population density, and in some cases the availability of other host species or anthropogenic sources of infection. Urbanised environments were associated with an increase in net weight of adult male quenda by 189.0g (95% CI 68.6-309.5g; p=0.002; adjusted R²=0.06) and adult female quenda by 140.1g (95% CI 3.9-276.3g; p=0.044; adjusted R²=0.07), with study findings suggesting a tendency towards obesity in urbanised environments. Adult female quenda in bushland had increased odds of an active pouch (adjusted OR=4.89, 95% CI 1.7-14.5), suggesting decreased reproductive activity in quenda from urbanised environments. These results highlight the subtle, yet extensive impacts that urbanised environments may have on wildlife ecology, even for those species which apparently adjust well to urbanisation.

Cat fleas (Ctenocephalides felis) carrying Rickettsia felis and Bartonella species in Hong Kong

Fleas are commonly recorded on stray as well as domestic dogs and cats in Hong Kong. Fleas can be a major cause of pruritus in dogs and cats and also vectors of potentially zoonotic bacteria in the genera Rickettsia and Bartonella. Morphological examination of 174 fleas from dogs and cats living in Hong Kong revealed only cat fleas (Ctenocephalides felis). Cytochrome c oxidase subunit 1 gene (cox1) genotyping of 20 randomly selected specimens, revealed three cox1 haplotypes (HK-h1 to HK-h3). The most common haplotype was HK-h1 with 17 specimens (17/20, 85%). HK-h1 was identical to cox1 sequences of fleas in Thailand and Fiji. HK-h1 and HK-h2 form a distinct cat flea cox1 clade previously recognized as the Clade 3. HK-h3 forms a new Clade 6. A multiplex Bartonella and Rickettsia real-time PCR of DNA from 20 C. felis found Bartonella and Rickettsia DNA in three (15%) and ten (50%) C. felis, respectively. DNA sequencing confirmed the presence of R. felis, B. clarridgeiae and Bartonella henselae. This is the first reported study of that kind in Hong Kong, and further work is required to expand the survey of companion animals in the geographical region. The sampling of fleas on domestic cats and dogs in Hong Kong revealed them to be exclusively infested by the cat flea and to be harbouring pathogens of zoonotic potential.

The Biology and Ecology of Cat Fleas and Advancements in Their Pest Management: A Review

The cat flea Ctenocephalides felis felis (Bouché) is the most important ectoparasite of domestic cats and dogs worldwide. It has been two decades since the last comprehensive review concerning the biology and ecology of C. f. felis and its management. Since then there have been major advances in our understanding of the diseases associated with C. f. felis and their implications for humans and their pets. Two rickettsial diseases, flea-borne spotted fever and murine typhus, have been identified in domestic animal populations and cat fleas. Cat fleas are the primary vector of Bartonella henselae (cat scratch fever) with the spread of the bacteria when flea feces are scratched in to bites or wounds. Flea allergic dermatitis (FAD) common in dogs and cats has been successfully treated and tapeworm infestations prevented with a number of new products being used to control fleas. There has been a continuous development of new products with novel chemistries that have focused on increased convenience and the control of fleas and other arthropod ectoparasites. The possibility of feral animals serving as potential reservoirs for flea infestations has taken on additional importance because of the lack of effective environmental controls in recent years. Physiological insecticide resistance in C. f. felis continues to be of concern, especially because pyrethroid resistance now appears to be more widespread. In spite of their broad use since 1994, there is little evidence that resistance has developed to many of the on-animal or oral treatments such as fipronil, imidacloprid or lufenuron. Reports of the perceived lack of performance of some of the new on-animal therapies have been attributed to compliance issues and their misuse. Consequentially, there is a continuing need for consumer awareness of products registered for cats and dogs and their safety.

Efficacy and safety of sarolaner (Simparica®) in the treatment and control of naturally occurring flea infestations in dogs presented as veterinary patients in Australia

BACKGROUND

The efficacy and safety of a novel isoxazoline compound, sarolaner (Simparica^®, Zoetis) and spinosad (Comfortis^®, Elanco) as a positive control were evaluated for the treatment and control of natural flea infestations on dogs in two randomised, blinded, multi-centric clinical trials conducted in 11 veterinary clinics in northeastern and southeastern states of Australia.

METHODS

A total of 162 client-owned dogs (80 in northern study and 82 in southern study) from 105 households were enrolled. Each household was randomly allocated to receive either sarolaner (Simparica^®, Zoetis) or spinosad (Comfortis^®, Elanco). Dogs were dosed on Days 0, 30 and 60 and physical examinations and flea counts were conducted on Days 0, 14, 30, 60 and 90. Efficacy assessments were based on the percentage reduction in live flea counts post-treatment compared to Day 0.

RESULTS

In the northern study, at enrolment, primary dogs had flea counts ranging from 5 to 772. At the first efficacy assessment on Day 14, sarolaner resulted in 99.3% mean reduction in live flea counts relative to Day 0, compared to 94.6% in the spinosad group. On Day 30, the sarolaner-treated group had mean efficacy of 99.2% compared to 95.7% in the spinosad-treated group, and on days 60 and 90, both groups had mean efficacies of ≥ 98.8%. In the southern study, at enrolment, primary dogs had flea counts ranging from 5 to 156. Both sarolaner and spinosad resulted in ≥ 96.7% mean reduction in live flea counts on Day 14. On Day 30, the sarolaner-treated group had mean efficacy of 99.5% compared to 89.7% in the spinosad-treated group, and on days 60 and 90, both groups had mean efficacies of ≥ 98.6%. No treatment-related adverse events were observed in either study.

CONCLUSIONS

A single monthly dose of sarolaner (Simparica^®) administered orally at 2-4 mg/kg for three consecutive months was well tolerated and provided excellent efficacy against natural infestations of fleas under a range of Australian field conditions including different climatic and housing conditions. Similar efficacy was observed with spinosad (Comfortis^®) after the second and third monthly treatments.

Serological evidence of exposure to Rickettsia felis and Rickettsia typhi in Australian veterinarians

BACKGROUND

Rickettsia felis and Rickettsia typhi are emerging arthropod-borne zoonoses causing fever and flu-like symptoms. Seroprevalence and risk factors associated with exposure to these organisms was explored in Australian veterinarians.

METHODS

One hundred and thirty-one veterinarians from across Australia were recruited to participate in a cross-sectional survey. Veterinarians provided a single blood sample and answered a questionnaire on potential risk factors influencing their exposure to R. felis and R. typhi. Indirect microimmunofluorescence antibody testing (IFAT) was used to identify evidence of serological exposure of the participants to R. felis and R. typhi. Results were analyzed and a logistical regression model performed to predict risk factors associated with seropositivity.

RESULTS

In total, 16.0% of participants were seropositive to R. felis, 4.6% to R. typhi and 35.1% seropositive to both, where cross-reactivity of the IFAT between R. felis and R. typhi precluded a definitive diagnosis. Veterinarians residing within the south-eastern states of Victoria and Tasmania were at a higher risk of exposure to R. felis or generalised R. felis or R. typhi exposure. Older veterinarians and those that recommended flea treatment to their clients were found to be significantly protected from exposure.

CONCLUSIONS

The high exposure to R. felis amongst veterinary professionals suggests that flea-borne spotted fever is an important cause of undifferentiated fever conditions that may not be adequately recognized in Australia.

Evidence of exposure to Rickettsia felis in Australian patients

Rickettsia felis is an emerging zoonosis, causing flea-borne spotted fever (FBSF). Serological diagnosis is typically confounded by cross-reactivity with typhus group rickettsiae and prior to the development of specific serological methods, cases of FBSF in Australia were misdiagnosed. Patient sera tested between August 2010 and December 2013 and known to be seropositive to R. typhi by immunofluorescence antibody testing (IFAT) were subsequently retested against R. felis using an R. felis-specific IFAT. Sera of 49 patients were of a sufficient quality to be included in re-analysis. A classification of FBSF and murine typhus (MT) was attributed to fourteen and seven patients respectively, based on a minimum four-fold higher antibody titre to R. felis than to R. typhi and vice versa. Twenty-eight patients were classified as indeterminate for either R. felis or R. typhi (antibody titres within two-fold of one another). Historically, it is likely that Australian patients clinically ill with FBSF were misdiagnosed. It is important that medical practitioners consider FBSF as part of their differential diagnoses, and obtain relevant history with regard to patient's exposure to domestic pets and their fleas. Australian microbiology diagnostic laboratories should include serological testing for R. felis as part of the diagnostic panel for febrile diseases. Veterinarians are encouraged to increase their awareness of this emerging zoonosis and advocate flea control in pets.

Molecular identity of cat fleas (Ctenocephalides felis) from cats in Georgia, USA carrying Bartonella clarridgeiae, Bartonella henselae and Rickettsia sp. RF2125

The cat flea (Ctenocephalides felis) is the most common ectoparasite of dogs and cats. Close association of humans with cats and dogs enables flea-borne disease transmission either directly, via flea bites, or indirectly, via pathogens excreted in flea faeces. The aim of this study was to evaluate molecular identity of C. felis from cats in Georgia, USA based on a molecular barcode marker gene (cox1) and the frequency at which the fleas were carriers of the vector-borne bacteria, Bartonella and Rickettsia. The multiplexed Bartonella and Rickettsia real-time PCR assay (targeting ssrA and gltA, respectively) adopted in this study, together with sequencing of the ssrA enabled rapid identification of Bartonella spp. in cat fleas. Eighteen out of 20 fleas examined were positive for Bartonella spp. and all fleas were positive for Rickettsia spp. DNA sequencing of the ssrA confirmed presence B. clarridgeiae and B. henselae. Amplification and DNA sequencing of gltA and ompA confirmed presence of Rickettsia sp. RF2125 (Rickettsia felis-like organism). All fleas from 21 cats in Georgia, USA were morphologically identical with C. felis. Sequencing of the flea cox1 revealed identity with C. felis from Seychelles, Africa recognised as a subspecies C. felis strongylus, the African cat flea. Analysis of the cox1 sequences of fleas improves understanding of global distribution of cat flea cox1 clades (C. felis) when compared with sequences from Ctenocephalides spp. from Asia, Africa, Europe, Asia and Australia. Coupling flea barcoding approach with the multiplexed real-time PCR assay followed by Bartonella sequencing represents a rational approach for screening and elucidation of fleas' capacity to vector infectious agents.

Insecticide Resistance in Fleas

Fleas are the major ectoparasite of cats, dogs, and rodents worldwide and potential vectors of animal diseases. In the past two decades the majority of new control treatments have been either topically applied or orally administered to the host. Most reports concerning the development of insecticide resistance deal with the cat flea, Ctenocephalides felis felis. Historically, insecticide resistance has developed to many of the insecticides used to control fleas in the environment including carbamates, organophosphates, and pyrethroids. Product failures have been reported with some of the new topical treatments, but actual resistance has not yet been demonstrated. Failures have often been attributed to operational factors such as failure to adequately treat the pet and follow label directions. With the addition of so many new chemistries additional monitoring of flea populations is needed.

Evaluation of the bacterial microbiome of two flea species using different DNA-isolation techniques provides insights into flea host ecology

Fleas (Siphonaptera) are ubiquitous blood-sucking pests of animals worldwide and are vectors of zoonotic bacteria such as Rickettsia and Bartonella. We performed Ion Torrent PGM amplicon sequencing for the bacterial 16S rRNA gene to compare the microbiome of the ubiquitous cat flea (Ctenocephalides f. felis) and the host-specific echidna stickfast flea (Echidnophaga a. ambulans) and evaluated potential bias produced during common genomic DNA-isolation methods. We demonstrated significant differences in the bacterial community diversity between the two flea species but not between protocols combining surface sterilisation with whole flea homogenisation or exoskeleton retention. Both flea species were dominated by obligate intracellular endosymbiont Wolbachia, and the echidna stickfast fleas possessed the endosymbiont Cardinium. Cat fleas that were not surface sterilised showed presence of Candidatus 'Rickettsia senegalensis' DNA, the first report of its presence in Australia. In the case of Rickettsia, we show that sequencing depth of 50 000 was required for comparable sensitivity with Rickettsia qPCR. Low-abundance bacterial genera are suggested to reflect host ecology. The deep-sequencing approach demonstrates feasibility of pathogen detection with simultaneous quantitative analysis and evaluation of the inter-relationship of microbes within vectors.

High phylogenetic diversity of the cat flea (Ctenocephalides felis) at two mitochondrial DNA markers

The cat flea, Ctenocephalides felis (Siphonaptera: Pulicidae) (Bouché), is the most common flea species found on cats and dogs worldwide. We investigated the genetic identity of the cosmopolitan subspecies C. felis felis and evaluated diversity of cat fleas from Australia, Fiji, Thailand and Seychelles using mtDNA sequences from cytochrome c oxidase subunit I (cox1) and II (cox2) genes. Both cox1 and cox2 confirmed the high phylogenetic diversity and paraphyletic origin of C. felis felis. The African subspecies C. felis strongylus (Jordan) is nested within the paraphyletic C. felis felis. The south East Asian subspecies C. felis orientis (Jordan) is monophyletic and is supported by morphology. We confirm that Australian cat fleas belong to C. felis felis and show that in Australia they form two distinct phylogenetic clades, one common with fleas from Fiji. Using a barcoding approach, we recognize two putative species within C. felis (C. felis and C. orientis). Nucleotide diversity was higher in cox1 but COX2 outperformed COX1 in amino acid diversity. COX2 amino acid sequences resolve all phylogenetic clades and provide an additional phylogenetic signal. Both cox1 and cox2 resolved identical phylogeny and are suitable for population structure studies of Ctenocephalides species.

An open, self-controlled study on the efficacy of topical indoxacarb for eliminating fleas and clinical signs of flea-allergy dermatitis in client-owned dogs in Queensland, Australia

BACKGROUND

Canine flea-allergy dermatitis (FAD), a hypersensitivity response to antigenic material in the saliva of feeding fleas, occurs worldwide and remains a common presentation in companion animal veterinary practice despite widespread availability of effective systemic and topical flea-control products.

HYPOTHESIS/OBJECTIVES

To evaluate the clinical response in dogs with FAD treated topically with indoxacarb, a novel oxadiazine insecticide.

ANIMALS

Twenty-five client-owned dogs in Queensland, Australia diagnosed with pre-existing FAD on the basis of clinical signs, flea-antigen intradermal and serological tests.

METHODS

An open-label, noncontrolled study, in which all dogs were treated with topical indoxacarb at 4 week intervals, three times over 12 weeks.

RESULTS

Twenty-four dogs completed the study. Complete resolution of clinical signs of FAD was observed in 21 cases (87.5%), with nearly complete resolution or marked improvement in the remaining three cases. Mean clinical scores (Canine Atopic Dermatitis Extent and Severity Index-03) were reduced by 93.3% at week 12. Mean owner-assessed pruritus scores were reduced by 88% by week 12. Mean flea counts reduced by 98.7 and 100% in weeks 8 and 12, respectively.

CONCLUSIONS AND CLINICAL IMPORTANCE

Topical indoxacarb treatment applied every 4 weeks for 12 weeks, without concomitant antipruritic or ectoparasiticide therapy, completely alleviated flea infestations in all dogs and associated clinical signs of FAD in a high proportion of this population of dogs in a challenging flea-infestation environment.

Molecular detection of Rickettsia felis and Bartonella henselae in dog and cat fleas in Central Oromia, Ethiopia

Fleas are important vectors of several Rickettsia and Bartonella spp. that cause emerging zoonotic diseases worldwide. In this study, 303 fleas collected from domestic dogs and cats in Ethiopia and identified morphologically as Ctenocephalides felis felis, C. canis, Pulex irritans, and Echidnophaga gallinacea were tested for Rickettsia and Bartonella DNA by using molecular methods. Rickettsia felis was detected in 21% of fleas, primarily C. felis, with a similar prevalence in fleas from dogs and cats. A larger proportion of flea-infested dogs (69%) than cats (37%) harbored at least one C. felis infected with R. felis. Rickettsia typhi was not detected. Bartonella henselae DNA was detected in 6% (2 of 34) of C. felis collected from cats. Our study highlights the likelihood of human exposure to R. felis, an emerging agent of spotted fever, and B. henselae, the agent of cat-scratch disease, in urban areas in Ethiopia.

Seroprevalence and risk factors for Rickettsia felis exposure in dogs from Southeast Queensland and the Northern Territory, Australia

Background

The recent detection of Rickettsia felis DNA in dogs in Australia suggests that dogs are potential mammalian reservoir hosts for this emerging rickettsia. To date, there is no published report addressing the seroprevalence of R. felis in dogs in Australia.

Methods

Antigens for R. felis were produced by inoculating confluent XTC-2 monolayer cell cultures with three pools of cat flea (Ctenocephalides felis) homogenates. Infection was confirmed by real-time (qPCR), conventional or nested PCRs targeting the ompB, gltA, 17 kDa and ompA genes. Two hundred and ninety-two dogs from Southeast Queensland and the Northern Territory were tested for the presence of R. felis antibodies using a microimmunofluorescence (IF) test and the seroprevalence and associated risk factors for exposure were determined using both uni- and multi-variate analyses.

Results

Rickettsia felis was successfully isolated in cell culture from all three cat-flea pools. One hundred and forty-eight dogs (50.7%) showed seropositivity with titres ≥64 and 54 (18.5%) with titres ≥128. At antibody titres ≥64, dogs with active ectoparasite control were less likely to be seropositive to R. felis (OR: 2.60; 95% CI: 1.20 - 5.56).

Conclusions

This first reported isolation of R. felis in cell culture in Australia allowed for the production of antigen for serological testing of dogs. Results of this serological testing reflects the ubiquitous exposure of dogs to R. felis and advocate for owner vigilance with regards to ectoparasite control on domestic pets.

Prevalence of fleas and gastrointestinal parasites in free-roaming cats in central Mexico

The prevalence of fleas and gastrointestinal parasites in free-roaming and domestic cats in central Mexico was evaluated. Three hundred and fifty eight cats captured in the street or brought in by owners to the Animal Control Center Unit, a unit of State Government, from June 2010 to May 2011, were included in the study. All cats were examined for the presence of fleas and gastrointestinal worms. One-hundred and ninety (53%) cats were infested with at least one flea species. Single infestations were observed in 106 (30%) cats and mixed infestations in 84 (23%) cats. Four species of fleas were recovered: Ctenocephalides felis in 53% of the cats, C. canis in 18%, Echidnophaga gallinacea in 7% and Pulex irritans in 1%. One-hundred and sixty three (45%) cats were infected with one or more species of gastrointestinal parasites: 48 (13%) with nematodes, 145 (40%) with cestodes, and one animal presented Moniliformis moniliformis. Prevalences and mean intensity of infection were: Physaloptera praeputialis 7 and 18; T. cati 3 and 2; Ancylostoma tubaeforme 2.5 and 2; Toxascaris leonina 0.5 and 2; Dipylidium caninum 36 and 32; Taenia taeniformis 4 and 3 and Moniliformis moniliformis 0.3 and 106, respectively. There was significant association (P<0.01), between season and ectoparasites load, more fleas were obtained in the summer and autumn than in the winter and spring; however, no statistical difference was observed for endoparasites load (P>0.05). The correlation between the total number of ectoparasites and endoparasites was not significant (r = 0.089, P = 0.094).

Single-dose field bioassay for sensitivity testing in sea lice, Lepeophtheirus salmonis: development of a rapid diagnostic tool

Sea lice on farmed salmonids are often treated with chemicals. Sensitivity testing of sea lice can reduce the number of treatments by identifying substances the sea lice are susceptible to. This study describes a simpler protocol for field sensitivity testing than today's six-dose bioassay. The protocol, which uses a single dose of the delousing agents deltamethrin, azamethiphos and emamectin benzoate, was developed on four different strains of sea lice and their subsequent generations. A sensitive strain and a strain showing reduced sensitivity were identified for each chemical after performing traditional bioassays and small-scale treatments. The single doses for each chemical were established by modelling dose-response curves from 24-h bioassays on strains with differences in sensitivity. The largest difference between the lower 80% prediction interval for the sensitive strain and the upper 80% prediction interval for the strain showing reduced sensitivity was identified for each delousing agent. The concentration of the chemical and the % mortality corresponding to each of the 80% prediction intervals were subsequently established. To validate the protocol for field use, further studies on both sensitive and resistant strains of sea lice under field conditions are required.

Molecular evidence of Rickettsia felis infection in dogs from Northern Territory, Australia

The prevalence of spotted fever group rickettsial infection in dogs from a remote indigenous community in the Northern Territory (NT) was determined using molecular tools. Blood samples collected from 130 dogs in the community of Maningrida were subjected to a spotted fever group (SFG)-specific PCR targeting the ompB gene followed by a Rickettsia felis-specific PCR targeting the gltA gene of R. felis. Rickettsia felis ompB and gltA genes were amplified from the blood of 3 dogs. This study is the first report of R. felis infection in indigenous community dogs in NT.