An Investigation into the Longevity of First Stage Larvae of Aelurostrongylus abstrusus

Abstract

After five to six weeks, and for a varying period thereafter, cats infested with Aelurostrongylus abstrusus evacuate first stage larvae in their faeces. Hobmaier and Hobmaier (1935), Blaisdell (1952) and MacKerras (1957) collected larvae for eight weeks, two years and seven months, respectively, after patency. Cameron (1927) found that larvae, extracted from faeces, lived for 11 days but were killed by freezing. Since the fate of such larvae is of importance with regard to the incidence of lungworm disease in the cat and because of the divergence of opinion concerning the viability of first stage larvae, it was considered necessary to establish the life-span of such larvae under various controlled conditions.

Effect of different temperatures on survival and development of Aelurostrongylus abstrusus (Railliet, 1898) larvae

“…At all tested temperatures, A. abstrusus L1s remained vital for a longer period in water rather than in faeces, as previously observed by Hamilton & McCaw (1967) for A. abstrusus and by Ramos et al . (2013) for T. brevior .…”

“…As already observed for other parasites, such as T. brevior , Angiostrongylus vasorum and Crenosoma vulpis (Croll & Al-Hadithi, 1972; Jeffery et al ., 2004; Morgen et al ., 2009; Ferdushy et al ., 2010; Ramos et al ., 2013), a reduction of the temperature, to some extent, creates favourable conditions for the survival of L1s; however, freezing temperatures can adversely affect larval survival. Conversely, it has been suggested that high temperatures (>24°C) negatively impact on the survival time of L1s of metastrongyloids (Hamilton & McCaw, 1967; Gökpinar & Yildiz, 2010; Ramos et al ., 2013). The lower mortality rate observed for L1s of groups W2 and F2 could be related with the metabolic activity of the larvae.…”

Distribution of the feline lungworm Aelurostrongylus abstrusus in the USA based on fecal testing

“…Once shed, L1s can live for a month in natural conditions until an intermediate host arrives and a higher percentage of L1s mature to L3s in warm climates. 2,19–20 Furthermore, not only can L3s survive in hibernating Helix aspersa snails, but L3s can also survive in paratenic hosts, thereby increasing the probability of being ingested by a cat. 21,22…”

Comparison of bronchoalveolar lavage fluid examination and other diagnostic techniques with the Baermann technique for detection of naturally occurring Aelurostrongylus abstrusus infection in cats

“…Potential A abstrusus infection was considered when there were 1-to 2-mm-diameter, firm, round, white foci scattered across the surface of the lungs or there was a mottled white and pink appearance to the lungs at necropsy. 3,19 For each feline cadaver, a section of the caudal part of the left caudal lung lobe was excised and preserved in neutral-buffered 10% formalin. The remaining respiratory tract was removed en bloc with the heart for further processing.…”