Larval development of Aelurostrongylus abstrusus in experimentally infected Rumina decollata snails

The Influence of Temperature on the Larval Development of Aelurostrongylus abstrusus in the Land Snail Cornu aspersum

The metastrongyloid Aelurostrongylus abstrusus has an indirect lifecycle involving gastropod intermediate hosts. The widespread snail Cornu aspersum is an efficient intermediate host of A. abstrusus. As the temperature may influence the developmental rate of metastrongyloids from first (L1) to the third infective larval stage (L3) inside molluscs, this study evaluated the effect of two controlled temperatures on the development of A. abstrusus in C. aspersum. Overall, 300 snails were infected with 500 L1 of A. abstrusus and kept at ∼25 °C. Fifteen days post infection (D15), the overall developmental rate to L3 (0.8%) was assessed in a subset of 20 snails. The remaining gastropods were divided in 2 groups, i.e., 180 still kept at ∼25 °C (G1) and 100 hibernated at ∼4 °C (G2). On D30, the larval development was evaluated in 20 snails from each group, while another batch of 80 snails was selected random from G1 and hibernated at ∼4 °C (G3). The larval developmental rate was determined digesting 20 snails from each of the three groups on D45, D60, and D75. The higher mean developmental rate was registered in G1 (3.8%) compared to G2 (1.9%) and G3 (2.3%), indicating that the development to L3 of A. abstrusus in C. aspersum is positively influenced by the increase of temperature.

Intermediate gastropod hosts of major feline cardiopulmonary nematodes in an area of wildcat and domestic cat sympatry in Greece

Background

The metastrongyloid nematodes Aelurostrongylus abstrusus, Troglostrongylus brevior and Angiostrongylus chabaudi are cardiopulmonary parasites affecting domestic cats (Felis catus) and wildcats (Felis silvestris). Although knowledge on these nematodes has been improved in the past years, gaps in our knowledge of their distribution and role of gastropods as intermediate hosts in Europe still exist. This study reports on the presence of these nematodes and their intermediate hosts in an area in Greece where domestic cats and wildcats occur in sympatry.

Methods

Terrestrial gastropods were collected in the field and identified morphologically and by mitochondrial DNA-sequence analysis. Metastrongyloid larvae were detected by artificial digestion, morphologically identified to the species and stage level and their identity was molecularly confirmed.

Results

Aelurostrongylus abstrusus was found in the snails Massylaea vermiculata and Helix lucorum, T. brevior in the slug Tandonia sp., and A. chabaudi in the slug Limax sp. and the snails H. lucorum and M. vermiculata.

Conclusions

To the best of our knowledge this study provides the first reports of (i) terrestrial gastropods being naturally infected with A. chabaudi, (ii) T. brevior naturally infecting terrestrial gastropods in Europe, and (iii) A. abstrusus naturally infecting terrestrial gastropods in Greece. Furthermore, the present study describes for the first time developmental stages of A. chabaudi and T. brevior in naturally infected gastropods. The biological characteristics of various intermediate gastropod hosts that could influence the distribution and expansion of feline cardiopulmonary nematodes are discussed, along with epizootiological implications and perspectives.

First molecular identification of Aelurostrongylus abstrusus in a cat presenting severe respiratory disease from Israel

Feline lung worm infection is increasingly reported in recent years, and recognized as a cause for respiratory disease in cats. Aelurostrongylus abstrusus is regarded as the most prevalent cause of such cases. Infective L3 larvae carried in gastropods and paratenic hosts infect felines, developing to adult worms that reside in the lungs' parenchyma and may cause verminous pneumonia. The L1 larvae hatch from eggs deposited in the lung, and are released to the environment by either feces or sputum. While the majority of epidemiological information regarding A. abstrusus originates in European countries, recent studies have shown that it is also found around the Mediterranean basin, as far east as Turkey and Cyprus. A local domestic cat from Israel showing signs of respiratory illness was diagnosed with aelurostrongylosis, confirmed by both morphological and molecular tools. Presence in Israel of this nematode was previously reported in 1949, with no further mentions since. ITS-2 sequence of the isolated larvae was highly similar to that of A. abstrusus from domestic cats from Italy. These findings show that distribution of A. abstrusus stretch to the eastern shores of the Mediterranean, and that this nematode should be considered as a cause for respiratory disease in cats in Israel and the surrounding countries.