Conference Agenda

Gastrointestinal nematodes (GIN) are a challenge for goat producers worldwide, causing high morbidity and mortality rates, and data pertaining to current GIN distribution in Australian goats is sparse. The objective of this study was to characterise the distribution of GIN in Queensland and New South Wales meat goats and explore influential factors. Between April 2022 and March 2024, 2,615 individual faecal egg counts (FEC) were conducted across 35 goat farms. All goats had not received anthelmintic treatment for at least 8 weeks prior to sampling. A number of effects were explored including rainfall, system intensity, supplementary feeding, breed and age. A high prevalence (96.7%) of GIN infection was observed, with 46% of goats responsible for 80% of total FEC output. The primary GIN species present were Haemonchus contortus and Trichostrongylus colubriformis. Significant differences (p < 0.05) were found in the FEC of goats across differing rainfall categories, system intensities, breeds, age classes and those that received supplementary feeding. The findings from this study indicate that GIN infection is a widespread issue for meat goat producers, and infection levels exist at magnitudes that indicate potential production losses.

Small strongyles (cyathostomin) infection in equines can cause clinical symptoms such as lethargy, sudden weight loss, debilitation, and diarrhoea. The encysted stages of cyathostomin can enter a dormancy stage called hypobiosis, which are not detected with a standard faecal egg count (FEC). Although a commercialised IgG(T) sera test identifying encysted larvae is available, the requirement for blood samples impedes its wide scale adoption. The aim of the current study was to investigate whether saliva can be used as an alternative to blood to detect antibodies against encysted larvae.

Saliva blood and faeces were collected at three timepoints (Spring, Autumn, and Winter) from horses (n=27) in regional Victoria, Australia. Blood was processed for IgG(T) antibodies against encysted stage larvae, the Mini-FLOTAC method was used to calculate FEC, and an IgA/IgG(T) ELISA was optimised for saliva. A positive correlation between sera and saliva IgG(T) in Winter was found (r=0.49, p=0.022). No correlations were observed with FEC for either blood or saliva. These results demonstrate antibodies to encysted stage larvae antigens used in the commercial test are also present in saliva and may have potential as an alternative test to detect encysted stage of cyathostomin infection in equines.

The pig industry contributes approximately AUD 5.2 billion annually to the Australian economy and provides around 36,000 full-time jobs across various sectors. Gastrointestinal parasites in pigs can lead to poor feed conversion and reduced weight gain, contributing to economic losses. Despite the recognised impact gastrointestinal parasites can have on pigs, little is known about their prevalence in Australia. This study aims to assess the prevalence of internal parasites across different pig production systems in Victoria through a cross-sectional coprological survey. A total of 50 commercial and backyard piggeries will be selected for the study. Approximately 30 faecal samples will be collected from each farm and tested using a modified McMaster technique. Selected parasite species will be characterised using morphological and genetic methods. Preliminary testing of samples from 29 farms shows a farm-level prevalence of 17% for Trichuris suis and 28% for coccidia (Cystoisospora suis/Eimeria spp.) in Victorian pigs. The findings of this project will generate baseline data and enhance our understanding of the prevalence of various internal parasites among pigs of different age groups and farming systems, thereby facilitating the development of effective parasite control strategies for Victorian pigs.

Ascaris suum is a significant internal parasite of pigs and is transmitted via faecal-oral route. It can result in reduced growth rate, poor intestinal absorption and contamination of livers with migrating larvae, leading to economic losses. Larval migration through the liver results in lesions (milk spots) and condemnation of livers at slaughter. The most commonly used diagnostic technique for detecting A. suum in live animals is the faecal egg count (FEC). However, this method cannot detect A. suum at the larval stages. This study investigates the effectiveness of enzyme-linked immunosorbent assay (ELISA) in diagnosing A. suum infection in pigs, by detecting antibodies against A. suum in pigs’ serum. Faecal, blood and liver samples will be collected from the pigs at the abattoir. A comparison of FEC results and liver milk spots scores to those of ELISA will help to identify early infection at larval stages. Preliminary screening of Victorian piggeries has identified 7% (2/29) of farms positive for A. suum infection using the FEC technique. The findings of the study will help to select an improved diagnostic technique for A. suum infection in pigs, resulting in timely detection of the parasite, thereby reducing economic losses.

Gastrointestinal nematode (GIN) infections cause economic losses in livestock and remains a global challenge for farmers. Haemonchus contortus is one of the most pathogenic GIN of small ruminants, often leading to death. In Victoria (Australia), outbreaks of H. contortus infections have been sporadic and linked to years with high rainfall. However, changing climatic conditions suggest infections may become more endemic and rapid and specific diagnosis is critical for effective treatment. Currently, Faecal Egg Counts (FEC) and larval cultures are the gold standard commercial diagnostic method which are carried out largely in regional, low technology laboratories. FEC are rapid but are limited by confirming patent infections, not GIN species. Conversely, larval culture allow species identification but are slow taking 1-2 weeks. There are many molecular diagnostic techniques used routinely in research allowing specific and rapid identification of GIN species including polymerase chain reaction (PCR), Loop-mediated isothermal amplification (LAMP) and sequencing of the ITS-2 rDNA region (nemabiome). This project will examine the commercial feasibility of such biomolecular tests in partnership with regional diagnostic laboratories to enable rapid diagnostics to confirm species presence. This will assist in the surveillance of H. contortus in Victoria throughout changing climatic conditions.

Managing parasites with fewer anthelmintic inputs requires a better understanding of parasite epidemiology, especially in situations where some species exhibit high levels of resistance and other species remain highly susceptible to anthelmintics. The seasonality of parasite species abundance has been difficult to establish because visual speciation of infective stage larvae is difficult. Now, relatively new DNA techniques have made this easier.

Nine farms distributed around New Zealand were enrolled in the project and tasked with sending in 10 fresh faecal samples from each of 3 stock classes of sheep (mixed age ewes, lambs and 2^nd year (2Tooth) ewes) on their property. Faecal nematode egg counts were performed on each sample and the remaining faeces was cultured by stock class. The resulting 3^rd-stage larvae (L3) were extracted, counted, and aliquoted for nemabiome sequencing.

As expected, initial results indicate differences in the species composition between age classes of sheep and regional variations, probably associated with climatic differences. Interestingly the seasonality of the species revealed by the data, raises some questions about the best time of year to carry out Faecal egg count reduction tests. As well as emphasising the need to truly know what species you have present when making treatment decisions.