Larval development of the feline lungworm Aelurostrongylus abstrusus in Helix aspersa

Abstract

The cat lungworm Aelurostrongylus abstrusus affects the domestic cat and other felids all over the world. Feline aelurostrongylosis is of importance in clinical feline medicine and is gaining more and more attention for the present expansion in the geographical range of A. abstrusus. Global warming and changes in phenology of snail intermediate hosts have been incriminated in this spreading. Helix aspersa, a potential vector of A. abstrusus, is endemic in most regions of the world, where it has become recently a pest outside its native Mediterranean range. The present work evaluated key features of larval development of A. abstrusus in H. aspersa at two different temperature conditions. The results showed that A. abstrusus may reach the infective stage in muscular foot and viscera of H. aspersa and that environmental temperatures may influence the biological cycle of the cat lungworm. In particular, the higher the average temperature, the higher the rate of larval development, i.e., about 50% of larvae of A. abstrusus reached the infective stage between temperatures of 18.8-29.5 °C, while only 17.8% of larvae completed their development at temperatures of 6.7-22 °C. Biological and epidemiological implications are discussed.

Larval development of the cat lungworm Aelurostrongylus abstrusus in the tropical freshwater snail Biomphalaria glabrata

“…In the study by Lopez et al (2005) nearly 5% of the L1 developed into L3. Di Cesare et al (2013) obtained an even higher development rate, with up to 50% developing in H. aspersa. In the present study the percentage of larvae completing their development into L3 was limited to 0.4%.…”

“…Environmental conditions were described to have an important impact on larval development in intermediate hosts: the maturation is faster and more larvae start and complete their development at higher temperatures, respectively, in summer, i.e. in H. aspersa snails infected with A. abstrusus (Di Cesare et al 2013;Giannelli et al 2014). As we kept the environmental factors constant at the indicated temperatures for B. glabrata under established experimental conditions, other reasons for this low development rate have to be considered.…”

“…Each pellet was re-suspended in tap water, centrifuged again and the sediment examined under the stereomicroscope. Larvae were stained with Lugol, photographed, measured by using a digital image processing system (Leica ® DM 100 LED, Leica ® DFC 420, Leica ® LAS 4, Leica Microsystems GmbH, Wetzlar, Germany) and morphologically identified based on previously described developmental stage characteristics (Gerichter, 1949;Di Cesare et al 2013). Starting from the day when all isolated larvae had developed into L3, the time interval between digestions was extended to every second week until the end of the trial (28 weeks post exposure, wpe).…”

“…Aelurostrongylus abstrusus has an indirect lifecycle in which gastropods serve as intermediate hosts (Hobmaier and Hobmaier, 1935;Gerichter, 1949) and various animals, such as rodents, reptiles and birds (Hamilton and McCaw, 1967;Scott, 1973;Jezewski et al 2013) can serve as paratenic hosts. Since Hobmaier and Hobmaier's studies (1935), different molluscs have been used as intermediate hosts and the development of A. abstrusus from first (L1) to third stage (L3) larvae has been described (Gerichter, 1949;Wallace and Rosen, 1970;Ash, 1970;Lopez et al 2005;Di Cesare et al 2013;Giannelli et al 2014).…”

Diagnosis and management of lungworm infections in cats

“…For instance, the higher the average temperature, the higher the rate of larval development of A abstrusus in Helix aspersa (Figure 3), the Mediterranean edible snail. 40 H aspersa, one of the most widely distributed land snails in the world, 41 has been deliberately or accidentally imported into different regions and is widely regarded as a pest outside its native Mediterranean range. 42 This mollusc is one of the most important intermediate hosts of A abstrusus and T brevior, and it is plausible that it has contributed (and is contributing) to the expansion of feline meta strongyloids in European countries.…”