Efficacy of Bravecto® Plus spot-on solution for cats (280 mg/ml fluralaner and 14 mg/ml moxidectin) in the prevention of feline Aelurostrongylus abstrusus infection evaluated in a multi-diagnostic approach

BACKGROUND

Aelurostrongylus abstrusus is one of the most important respiratory nematodes of felines. Infections may lead to respiratory clinical signs with varying severity or even death, emphasizing the need for preventive treatment of cats with outdoor access to circumvent patent infections.

METHODS

Therefore, the preventive efficacy of a spot-on formulation of 280 mg/ml fluralaner and 14 mg/ml moxidectin (Bravecto® Plus spot-on solution for cats, MSD) against A. abstrusus was evaluated in a negative controlled, randomized and partially blinded efficacy study with 28 purpose-bred cats in a non-terminal design. In three different treatment regimes, the minimum recommended dose of 40 mg fluralaner and 2.0 mg moxidectin/kg bodyweight (BW) was administered once at 12, 8 or 4 weeks (study group G1, G2 and G3, respectively) prior to experimental infection with 300 third-stage A. abstrusus larvae, while G4 served as placebo-treated control.

RESULTS

From 30 to 46 days post infection (dpi; SD 114 to 130), faeces were sampled to monitor first-stage larvae (L1) excretion for efficacy determination. Secondary efficacy criteria, including respiratory parameters, serological antibody levels and computed tomography (CT) findings, were assessed once before enrolment (SD -7 to -1) and before infection (SD 75 to 83). After infection, CT evaluation was performed once at 47-50 dpi (SD 131 to 134), and respiratory parameters and antibody levels were regularly assessed twice or once a week, respectively (1 up to 78 dpi, SD 85 up to 162). All animals in the control group excreted L1 by 33-37 dpi and remained positive throughout the study period from 41 to 46 dpi (SD 125 to 130). In the treatment groups, only one animal each of G1 and G2 excreted L1 at two consecutive days, and four cats of G1, two of G2 and three of G3 were positive on single occasions. While the geometric mean (GM) of the maximum number of excreted L1 per 5 g of faeces was 7380.89 in the control group (G4), GMs were significantly lower in the treatment groups with 1.63 in G1, 1.37 in G2 and 0.79 in G3. Thus, based on GMs, the reduction in excreted L1 exceeded 99.9% in all three treatment groups. Based on CT severity scores, all lungs of the animals of the control group showed severe pulmonary changes post infection, whereas lungs of the cats of the treatment groups were either unaltered (4 animals), mildly (11 animals), or moderately altered (5 animals). Moreover, seroconversion was observed in all cats of the control group, but not in those of the treatment groups.

CONCLUSIONS

The combination of diagnostic methods used in this non-terminal study yielded coherent and reliable results. A single administration of Bravecto® Plus spot-on solution for cats was well tolerated and effective in the prevention of aelurostrongylosis for at least 12 weeks.

1758) in Bosnia and Herzegovina: histopathological and parasitological findings

This paper represents the first description of advanced aelurostrongylosis in the Eurasian badger (Меles meles, L. 1758) from Bosnia and Herzegovina, which is an autochthonous species of the country. An adult female badger was found dead on a road; the cause of death was trauma but the emphasis in the paper is on severe verminous pneumonia caused by metastrongylids from genus Aelurostrongylus spp. This parasitological and histopathological finding confirms the presence of Aelurostrongylus in mustelids in Bosnia and Herzegovina and the Balkans.

Updates on feline aelurostrongylosis and research priorities for the next decade

Feline aelurostrongylosis, caused by the metastrongyloid nematode Aelurostrongylus abstrusus, is an important gastropod-borne parasitic lung disease in cats. Infection with A. abstrusus is widespread globally, but the increasing awareness of this parasite and the advent of more sensitive diagnostics have contributed to the apparent increase in its prevalence and geographic expansion. Clinical features may range in severity from subclinical to life-threatening respiratory disease. Parasitological standard techniques, such as visualization of the nematode first larval stage in faecal and respiratory (bronchial mucus or pleural fluid) samples, remain the mainstays of diagnosis. However, diagnosis is evolving with recent advances in serological and molecular testing, which can improve the time to initiation of effective anthelmintic therapy. Despite numerous anthelmintics that are now available as treatment options, the role of host immunity and lifestyle factors in selecting cats that may benefit from more targeted anthelmintic prophylaxis or treatment practice remains unclear and is likely to guide therapeutic choices as newer data become available. This review summarizes the biology, epidemiology, pathophysiology, diagnosis and treatment options currently available for feline aelurostrongylosis.