Meerkats (Suricata suricatta), a new definitive host of the canid nematode Angiostrongylus vasorum

Abstract

Angiostronglyus vasorum is a cardiopulmonary nematode infecting mainly canids such as dogs (Canis familiaris) and foxes (Vulpes vulpes). Natural infections have also been reported in mustelids and red pandas (Ailurus fulgens fulgens). We report the occurrence of natural A. vasorum infections in a group of captive meerkats (Suricata suricatta), housed at a university facility in Switzerland. A. vasorum first-stage larvae (L1) were initially identified in a pooled faecal sample. Individual samples, investigated with the Baermann-Wetzel technique, revealed that 41% (7/17) of the meerkats were infected, with ranges of 2-125 L1/g faeces. PCR and sequencing of part of the ITS-2 region resulted in 100% identity with A. vasorum. Infected animals did not show clinical signs. One meerkat died two days after diagnosis. Upon necropsy one adult specimen was recovered; histological examination of the lung revealed granulomatous pneumonia caused by A. vasorum larvae and eggs as well as intima and media hyperplasia and isolated arteriosclerosis of larger lung vessels. However, the cause of death was a spleen rupture with associated blood loss. All meerkats were topically treated with 10 mg imidacloprid/2.5 mg moxidectin per animal, after which they became negative in all follow up faecal examinations. Potential intermediate (gastropods) and paratenic hosts (birds) were collected from within or outside the meerkats enclosure. Gastropods were examined by PCR and bird samples by digestion. Four out of 193 (2.1%) gastropod samples were positive for A. vasorum, whereas none of the bird samples were positive. Meerkats, belonging to the Herpestidae, therefore are suitable definitive hosts for A. vasorum, with production and excretion of live L1. Meerkats kept in captivity in areas where A. vasorum is endemic and with potential contact to intermediate hosts are at risk of infection. Regular faecal examinations including Baermann-Wetzel technique should be considered.

Keywords: Angiostrongylus vasorum; Cardiopulmonary nematode; Meerkat; New definitive host; Suricata suricatta.

Graphical abstract

Fig. 1

Angiostrongylus vasorum first stage larva isolated by the Baermann technique from a collective faecal sample of a meerkat group. Average size: 332 μm in length and 14.1 μm in width.

Fig. 2

Sequence alignment of part of the internal transcribed spacer (ITS) 2-region (78 bp) of Angiostronglus vasorum (GenBank accession no. KF270683), of DNA isolated from A. vasorum first stage larvae obtained from meerkats and from one slug.

Fig. 3

Histological image of the lung of an Angiostrongylus vasorum infected meerkat. An adult nematode within a thickened artery (A), larvae and eggs surrounded by plasma cells, macrophages, neutrophilic granulocytes and lymphocytes (B) are visible, indicating granulomatous pneumonia as well as intima and media hyperplasia of larger lung vessels. (Hematoxylin and eosin staining, original magnification x 100 (A), x 400 (B)).

Fig. 4

Agarose gel (1.5%) stained with GelRed™ showing PCR products of part of the internal transcribed spacer (ITS) 2-region of Angiostrongylus vasorum of 37 gastropod samples: samples no. 8, 23, 29 and 35 were positive. M: DNA ladder, N: negative control, P: positive control.