Confirmation of the occurrence of the nematode parasite Lamanema chavezi Becklund , 1963 in South American camelids in New Zealand

Suspicions of the occurrence of Lamanema chavezi in New Zealand were first reported when some unusual worm eggs were detected in faecal samples from llamas (Lama glama) and alpacas (Vicugna pacos) on a property in Canterbury in 2005 (McKenna 2006). Although the eggs resembled those of Nematodirus spp., measuring 175 x 76 μm (mean of five), they differed from them in being flatter-sided and having a morula in a further stage of development than the typical eight cell-stage normally associated with freshly excreted Nematodirus spp. eggs. They also had an obvious yellowish-brown colouration atypical of eggs of members of this genus, apart, perhaps, from those of N. battus, which have been variously described as “markedly brown” (Thomas 1959) or “coffee coloured” (Jansen 1973). Similar eggs were subsequently detected in the faeces of a further five llamas and alpacas from the same property.
Incubation of these eggs at 27°C showed that they completed their development to the third larval stage while still within the egg. However, even after more than 30 days at this temperature very few hatched. Examination of the third-stage larvae mechanically released from these eggs revealed that they were, at around 700 μm long, considerably shorter than those of Nematodirus species, and that they lacked the long whip-like tail-sheaths typical of members of this genus. Accordingly, based both on the morphological features of the eggs and the third-stage larvae, as well as the idiosyncrasies of the embryonic development and delayed hatching, it was deduced that these eggs and larvae were likely to be those of Lamanema chavezi (McKenna 2006). Unfortunately, it was not possible to provide confirmation of identity by examination of adult worms at that time.
Following this initial presumptive finding a second occurrence of suspected Lamanema infection on another property in Canterbury was investigated in April 2009….continued