Prevalence of feline lungworm Aelurostrongylus abstrusus in England

Epidemiological Survey on Gastrointestinal and Pulmonary Parasites in Cats Around Toulouse (France)

Various feline parasites are potentially zoonotic thus establishing factors associated with parasitism is of animal and public health interest. The aim of this study was to determine the prevalence of endoparasites in client-owned cats, living in the area of Toulouse, France, over the period 2015 - 2017, and to investigate possible risk factors. A total of 498 faecal samples from cats of the University Animal Hospital of Ecole Nationale Vétérinaire de Toulouse were analysed, 448 from cats presented for consultation and 50 at post-mortem. Analysis was performed using a commercial flotation enrichment method with a hypersaturated sodium chloride solution and Baermann technique. Further examination of the gastrointestinal tract contents was conducted on necropsied cats. Overall, 11.6 % of cats were positive for endoparasites; 50 (11.2 %) consultation cases and 8 (16 %) post-mortem cases, with no significant difference in prevalence between the groups. Amongst infected cats, most were infected by a single species of parasite and 10.3 % (n=6) were infected with two or more. The most common parasite was Toxocara cati with a prevalence of 9.4 % (n=47). Other endoparasites encountered were: Cystoisospora sp 1.0 % (n=5), Aelurostrongylus abstrusus 1.0 % (n=5), Strongyloides sp 0.6 % (n=3), Dipylidium caninum 0.4 % (n=2), Aonchotheca putorii 0.2 % (n=1), Ancylostomatidae 0.2 % (n=1) and Toxascaris leonina 0.2 % (n=1). The examination of the gastronintestinal tract contents of the necropsied cats revealed Mesocestoides sp 0.4 % (n=2) and Tænia (Hydatigera) tæniaeformis sensu lato 0.2 % (n=1) which are seldomly diagnosed by flotation methods. In this study, increasing age and neutered status were statistically associated with reduced odds of infection by endoparasites (helminth and coccidian). Predictors of significantly increased risk included being male, intact, and not receiving regular anthelmintic treatment. The same risk factors were highlighted specifically for Toxocara cati infections, with rural location being an additional risk factor for infection.

Cardiorespiratory nematodes and co-infections with gastrointestinal parasites in new arrivals at dog and cat shelters in north-western Spain

Metastrongyloid and trichuroid cardiorespiratory nematodes of dogs and cats are considered emergent in several European countries, and an increase in the number and extent of endemic foci has been described. Since data on their prevalence are limited in this continent, faecal samples from new arrivals (365 dogs and 65 cats) at two animal shelters in North-western Spain were analysed using both floatation and Baermann techniques. In order to confirm the microscopic identification of Metastrongylidae first stage larvae, molecular characterization based on the sequence of the ITS-2 was performed. The possible influence of some variables such as the species, sex and age of the animals and the co-infection with other gastrointestinal parasites on the prevalence of cardiorespiratory nematodes was analysed. The most prevalent metastrongylid was Aelurostrongylus abstrusus (15.4%) followed by Angiostrongylus vasorum (4.1%) and Crenosoma vulpis (1.1%). Regarding trichuroids, Eucoleus aerophilus and/or Eucoleus boehmi eggs were detected in 28 dogs (7.7%) and four cats (6.2%). Almost all animals positive to cardiorespiratory nematodes (86.8%) were co-infected with gastrointestinal parasites. The prevalence of Metastrongylidae and respiratory trichuroids was significantly higher in dogs co-infected with Taenia spp. and Toxocara canis or Giardia duodenalis and Sarcocystis spp., respectively. In cats, a significant higher prevalence of Metastrongylidae nematodes was found in animals co-infected with Toxocara cati. Our results reveal that cardiorespiratory nematodes are common in companion animals from north-western Spain, showing higher prevalences than those previously reported from this country. This investigation represents the first report of C. vulpis, E. aerophilus and E. boehmi in dogs from Spain. The identification of a number of zoonotic parasites is of public health concern. Our results indicate that these nematodes should be included in the differential diagnosis of dogs and cats from north-western Spain showing respiratory or cardiac clinical signs.

A Molecular Survey on Neglected Gurltia paralysans and Aelurostrongylus abstrusus Infections in Domestic Cats (Felis catus) from Southern Chile

Gurltia paralysans and Aelurostrongylus abstrusus are neglected metastrongyloid nematode species which infect domestic and wild cats in South American countries and in Chile, but no epidemiological studies on concomitant infections have been conducted in Chile so far. The aim of this study was not only to evaluate the occurrence of concomitant infections, but also to identify epidemiological risk factors associated with of G. paralysans and A. abstrusus infections in urban domestic cats (Felis catus) from Southern Chile. Blood samples from clinically healthy domestic cats from three cities of Southern Chile-Temuco, Valdivia, and Puerto Montt-were analyzed by an experimental semi-nested PCR protocol. A total of 171 apparently healthy domestic cats in Temuco (n = 68), Valdivia (n = 50), and Puerto Montt (n = 53) were sampled and analyzed. A total of 93 domestic cats (54.4%) were positive for G. paralysans, and 34 (19.9%) were positive for A. abstrusus infections. From those animals, 34 (19.9%) were co-infected. Cats positive with G. paralysans were found in all three cities; 47.2% in Puerto Montt, 48% in Valdivia, and 64.7% in Temuco. Levels of infection for A. abstrusus in the population under study were 4% (Valdivia), 10% (Puerto Montt), and 32.4% (Temuco). The present large-scale epidemiological study confirmed the presence of these neglected nematodes in domestic cat populations in Southern Chile, and described the possible risk factors associated with feline gurltiosis and aelurostrongylosis.

Autochthonous Angiostrongylus cantonensis, Angiostrongylus vasorum and Aelurostrongylus abstrusus infections in native terrestrial gastropods from the Macaronesian Archipelago of Spain

The presence of zoonotic relevant Angiostrongylus cantonensis infections has recently been reported in rat final hosts and gastropod intermediate hosts in Tenerife, Spain. However, data on A. cantonensis, Angiostrongylus vasorum and Aelurostrongylus abstrusus prevalences in endemic gastropods for other islands of the Macaronesian Archipelago are still missing. In order to fill this gap, we conducted an epidemiological study on terrestrial native slug (Plutonia lamarckii) and snail (Cornu aspersum, Theba pisana, Rumina decollata) species in 27 selected locations of Tenerife, Gran Canaria, El Hierro, Lanzarote, La Palma and Fuerteventura. Overall, 131 terrestrial gastropods were collected in winter/spring season 2018/2019 and examined for the presence of metastrongyloid lungworm larvae via artificial digestion. The current data revealed a total prevalence of 4.6% for A. vasorum, 3.8% for A. abstrusus and 0.8% for A. cantonensis. In Tenerife, three lungworm species were detected, thereby re-confirming A. cantonensis endemicity for this island. Prevalences of snails (C. aspersum) originating from El Hierro were 5% for A. abstrusus and 15% for A. vasorum, respectively, with larval burdens up to 290 larvae per specimen. This epidemiological study indicates the presence of human, canine and feline lungworm species in Macaronesia, Spain. The current data-particularly those on anthropozoonotic A. cantonensis-call for a regular large-scale monitoring on intermediate hosts, paratenic hosts and definitive hosts to prevent further spread of lungworm-related diseases in humans and animals.

Efficacy of Bravecto® Plus spot-on solution for cats (280 mg/ml fluralaner and 14 mg/ml moxidectin) for the prevention of aelurostrongylosis in experimentally infected cats

Background

The feline lungworm Aelurostrongylus abstrusus affects the lower respiratory tract in cats worldwide. As infections may lead to chronic respiratory changes or even death, preventive treatment in cats with outdoor access is warranted.

Methods

The preventive efficacy of a spot-on solution (Bravecto® Plus spot-on solution for cats, MSD) against cat aelurostrongylosis was evaluated using three different preventive treatment regimes in a negative controlled, randomized and partially blinded laboratory efficacy study with 31 purposed-bred cats. The minimum recommended dose of 2.0 mg moxidectin + 40 mg fluralaner/kg bodyweight was applied once 12 (Group [G]1), 8 (G2) or 4 (G3) weeks before experimental infection with 300 third-stage larvae (L3) of A. abstrusus. Another group served as untreated control (G4). Individual faecal samples were analysed as of day 30 post infection (pi) to monitor larvae excretion. Necropsy was performed at days 47–50 pi. The lungs were examined macroscopically for pathological findings and (pre-)adult worms were counted to assess preventive efficacy.

Results

Beginning at day 32–40 pi, all cats of the control group were constantly shedding larvae of A. abstrusus, whereas only one animal of G1 excreted larvae at several consecutive days. In addition, two cats of G1 and G3 and three of G2 were positive on a single occasion. The geometric mean (GM) of the maximum number of excreted larvae was 7574.29 in the control group compared to 1.10 (G1), 1.19 (G2) and 0.53 (G3), resulting in a GM reduction of > 99.9% in all treatment groups. All lungs of the control animals showed severe or very severe alterations at necropsy, while in 94.44% of the treated cats lung pathology was rated as absent or mild. The GM number of (pre-)adult A. abstrusus retrieved from the lungs was 26.57 in the control group, 0.09 in G1 and 0.00 in G2 and G3. Thus, GM worm count reduction was 99.66% in G1 and 100% in G2 and G3.

Conclusions

A single application of Bravecto® Plus spot-on solution at a dose of 2.0 mg moxidectin + 40 mg fluralaner/kg bodyweight reliably prevents cat aelurostrongylosis for at least 12 weeks.

Felid Cardiopulmonary Nematodes: Dilemmas Solved and New Questions Posed

In the past decade cardiopulmonary nematodes affecting felids have become a core research topic in small animal parasitology. In the late 2000s, an increase in studies was followed by unexpected findings in the early 2010s, which have stimulated research teams to start investigating these intriguing parasites. Prolific scientific debate and exchanges have then fostered field and laboratory studies and epi-zootiological surveys. New data have improved basic and applied knowledge, solved dilemmas and posed new questions. This article discusses the past and present background to felid cardiopulmonary nematodes after the last few years of intense scientific research. New data which have demonstrated the key role of Aelurostrongylus abstrusus and Troglostrongylus brevior in causing respiratory infections in domestic cats, and on the nil to negligible current importance of other species, i.e., Troglostrongylus subcrenatus, Oslerus rostratus and Angiostrongylus chabaudi, are presented. Biological information and hypothesized alternative routes of infection are analysed and discussed. Novel identification and taxonomical data and issues are reported and commented upon. On the whole, recent biological, ecological and epi-zootiological information on felid meta-strongyloids is critically analysed, with the aim to answer outstanding questions, stimulate future studies, and underline new research perspectives.

Feline lungworms in Greece: copromicroscopic, molecular and serological study

Aelurostrongylus abstrusus (Nematoda, Metastrongyloidea) causes verminous pneumonia in cats worldwide. This study evaluated the seroprevalence of A. abstrusus antibodies in 220 stray and free-roaming cats from insular (Mykonos, Crete, Skopelos) and continental (Thessaloniki, Attica) Greece. The results were compared with morphological and biomolecular identification of first-stage larvae (L1) in faeces. Positive cats were observed in all 5 areas: 13/97 (13.4%), 1/32 (3.1%), 7/26 (26.9%), 3/18 (16.7%) and 5/47 (10.6%) cats tested positive for A. abstrusus L1 by Baermann examination, and 33/97 (34.0%), 7/32 (21.9%), 6/26 (23.1%), 3/18 (16.7%) and 11/47 (23.4%) were seropositive, in Mykonos, Crete, Skopelos, Thessaloniki and Attica, respectively. Troglostrongylus brevior L1 were found in 12/97 (12.4%), 3/26 (11.5%) and 2/47 (4.3%) cats from Mykonos, Skopelos and Attica respectively. Six of the 220 cats (2.7%), i.e. 4/97 (4.1%) from Mykonos and 2/26 (7.7%) from Skopelos, shed L1 of both A. abstrusus and T. brevior. Sixty samples were ELISA-positive (27.3%, 95% CI: 21.5-33.7%), of which 21 (35%) tested copromicroscopically positive (19 monospecific infections and 2 mixed with Troglostrongylus brevior), and 5 were positive for T. brevior L1 only. Among seronegative cats (n = 140), L1 of A. abstrusus were additionally detected in 8 (5.7% out of 140) cats (i.e. 4 monospecific infections and 4 mixed with T. brevior), and in 6 (4.3% out of 140) cats, L1 of T. brevior as monospecific infection were detected. This study confirms the presence of lungworms in Greece and suggests that the number of cats infected with/exposed to metastrongylids is higher than detected by faecal examinations.

Efficacy of imidacloprid 10%/moxidectin 1% spot-on formulation (Advocate®) in the prevention and treatment of feline aelurostrongylosis

Background

In three randomized, controlled laboratory efficacy studies, the efficacy in the prevention of patent infections of a topical combination of imidacloprid 10%/moxidectin 1% (Advocate® spot-on formulation for cats, Bayer Animal Health GmbH) against larval stages and immature adults of Aelurostrongylus abstrusus, as well as the treatment efficacy of a single or three monthly treatments against adult A. abstrusus, were evaluated.

Methods

Cats were experimentally inoculated with 300–800 third-stage larvae (L3). Each group comprised 8 animals and the treatment dose was 10 mg/kg bodyweight (bw) imidacloprid and 1 mg/kg bw moxidectin in each study. Prevention of the establishment of patent infections was evaluated by two treatments at a monthly interval at three different time points before and after challenge infection. Curative efficacy was tested by one or three treatments after the onset of patency. Worm counts at necropsy were used for efficacy calculations.

Results

In Study 1, the control group had a geometric mean (GM) of 28.8 adult nematodes and the single treatment group had a GM of 3.4 (efficacy 88.3%). In Study 2, the control group had a GM of 14.3, the prevention group had a GM of 0 (efficacy 100%), while the treatment group had a GM of 0.1 (efficacy 99.4%). In Study 3, the GM worm burden in the control group was 32.6 compared to 0 in all three prevention groups (efficacy 100% for all of those groups).

Conclusions

The monthly administration of Advocate® reliably eliminated early larval stages and thereby prevented lung damage from and patent infections with A. abstrusus in cats. Regarding treatment, a single application of Advocate® reduced the worm burden, but it did not sufficiently clear the infection. In contrast, three monthly treatments were safe and highly efficacious against A. abstrusus.