Epidemiology of gastrointestinal nematodes of alpacas in Australia: II. A longitudinal study

Two centrifugal flotation techniques for counting gastrointestinal parasite eggs and oocysts in alpaca faeces

Introduction

The alpaca (Vicugna pacos) is a camelid native to South America, but the species has wide distribution outside its natural habitat and is found in various countries on other continents, Poland being one in Europe. Parasitic infections affect the productivity and health of alpacas. The aim of the study was to estimate the parasite loads in alpacas kept in Poland with the use of two direct centrifugal flotation methods.

Material and Methods

A total of 248 faecal samples from alpacas from 12 provinces in Poland were examined for parasite eggs and oocysts with a modified Willis method (WM), and 59 samples were examined simultaneously with WM and a modified Stoll method (SM).

Results

The WM detected eggs of Trichostrongylidae, and the SM oocysts of Eimeria spp. as the respective most prevalent parasite material. The eggs of Nematodirus sp., Nematodirus battus, Aonchotheca sp., and Trichuris sp. were detected in lower numbers in both methods. Oocysts of E. macusaniensis and eggs of Moniezia sp. were the rarest in WM, the former also being so in SM; eggs of Moniezia were absent in SM. The prevalence of Eimeria spp. was significantly higher as detected by SM than as detected by WM; however, the prevalence of eggs of Nematodirus spp. and trichostrongyles was significantly higher as detected by WM than as detected by SM.

Conclusion

WM is more accurate at detecting heavy gastro-intestinal nematode eggs, including those of trichostrongyles and Nematodirus, whereas SM is more accurate at detecting smaller coccidia from the genus Eimeria.

Worm burdens and associated histopathological changes caused by gastrointestinal nematodes in alpacas from Australia

In this study, 100 gastrointestinal tracts of Australian alpacas were examined to assess the worm burden and to identify the species of nematode present. Faecal samples were collected from 97 alpacas and processed for faecal egg counts (FECs). For identification of the species, both molecular (multiplexed-tandem polymerase chain reaction [MT-PCR]) and morphological techniques were used. Total worm counts (TWCs) revealed a mean burden of 1300 worms, with the highest burden of 29,000 worms. The average egg count was 501 eggs per gram of faeces (EPG), with the highest count of 3500 EPG. Nineteen different species of gastrointestinal nematodes (GINs) were identified, and Graphinema auchenia, Camelostrongylus mentulatus and Trichuris tenuis were recovered from Australian alpacas for the first time. Haemonchus contortus was the most prevalent nematode (81%) followed by C. mentulatus (60%). The majority of the nematodes found are shared with sheep, goats and cattle. Findings of this study provide useful insights into the spectrum of GINs and their burden in Australian alpacas.