Vaccination of sheep and cattle against haemonchosis

Abstract

Vaccines against gastrointestinal nematodes are one potential option for the control of parasitic gastroenteritis in ruminants. Excretory/secretory (E/S) and hidden antigens are being studied as candidates for vaccines against Haemonchus spp., which is a major parasite in cattle and small ruminants that are raised in warm climates. Protection has been observed after vaccination with some E/S proteases, particularly cysteine proteases and with some glycans that are abundant on the surfaces and in the secretory products of helminths. However, the most promising results are being obtained with glycoprotein antigens extracted from the microvillar surfaces of the Haemonchus contortus intestinal cells. These antigens are called 'hidden' because they are not exposed to the host's immune system during infection. Thus far, recombinant forms of these antigens have not been usefully protective. However, because only 5 μg of antigen is required per dose, production of a native antigen vaccine from adult parasites has been found to be practical and commercially viable. Trials indicate that a vaccine made from one particular isolate will cross-protect against geographically distant isolates.

Extensive genomic and transcriptomic variation defines the chromosome-scale assembly ofHaemonchus contortus, a model gastrointestinal worm

“…The nematode Haemonchus contortus is one such species. H. contortus is a major pathogen of sheep and goats worldwide and is recognised as a model parasite due to its experimental tractability for drug discovery [16,17] , vaccine development [18,19] and anthelmintic resistance research [20] . Draft genome assemblies were published in 2013 for two anthelmintic-sensitive isolates, MHco3(ISE).N1 [21] and McMaster [22] ; both assemblies were produced with a combination of short-read, high-throughput sequencing technologies (including both short-and long-insert libraries), resulting in estimated genome sizes of 370 Mbp and 320 Mbp, respectively.…”

A genome resequencing-based genetic map reveals the recombination landscape of an outbred parasitic nematode in the presence of polyploidy and polyandry

“…Anthelmintic drug failure is an important economic and animal health problem, as anthelmintic resistance is widespread on farms, and populations and isolates resistant to all major classes of anthelmintics have been described [34-36]. Accordingly, significant research effort is focused on the development of novel anthelmintics [37] or vaccines [38] for parasite control. Although research on H. contortus has been instrumental in understanding some of the mechanisms by which resistance arises [34, 39], the genetic basis of resistance remains largely unresolved and is likely complex.…”

Vaccines againstTrichinella spiralis: Progress, challenges and future prospects

“…During the processes of host–parasite interactions, ES antigens are recognized to induce effective immune responses, which have been utilized in several instances against infection of helminths (Bassetto & Amarante, ; El Ridi, Tallima, Mahana, & Dalton, ; Lightowlers & Rickard, ). The major sources of ES products include not only the molecules released from specialized excretory or secretory organs but also the material shed from the cuticular and tegumental surfaces (Lightowlers & Rickard, ).…”