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在猪种群中针对寄生虫接种疫苗很少。实际上，目前尚无猪寄生虫感染的市售疫苗。这主要是因为寄生虫感染的免疫力如此之缓慢，以至于动物去屠宰的时间没有足够的时间让疫苗值得。

However, developing vaccines for use against parasites is still a significant area of research, in both medical and veterinary fields. Zoonotic parasites in particular attract the attention of those involved in the一个健康运动, a collaboration across all scientific health- and environment-related disciplines, due to their ability to be transferred via the food-chain. In fact, the only anti-parasite vaccine currently in use in pigs – though not commercially available – is theanti-Cycticercus cellulosae-vaccine, to prevent porcine cycticercosis, which can lead to the tapeworm (taenia solium) in humans.

Current methods of parasite control

As parasites are not currently a major concern within swine production, a blanket approach to anti-parasitic treatment is often applied, not driven by an individual diagnosis. Drugs are usually given during the pre-patent phase, before parasites are easily detectable in routine screening, in an effort to prevent environmental transmission of the parasite. However, overuse of these drugs raises concerns about increased likelihood of resistance, and with no routine tests, parasiticide resistance goes under-reported. This method of treating infection has also seen a rise in drug residues detected in meat, which may get into the food chain.

不幸的是，由于较高的患病率和鸡蛋在宿主外生存很长时间的能力，因此很难完全消除牛群的感染。例如，Ascaris suum（大round虫）鸡蛋非常耐用，在正确的条件下可以在土壤中存活多年。

Other practices like chemical disinfection and all-in-all-out production (the system of grouping similar aged pigs together for the entire production process, breaking the chain of infection and preventing disease spread) can help reduce the spread of parasitic infections but are unlikely to be able to eliminate it.

What are the best candidates for vaccines?

开发牲畜疫苗时，需要寻找许多关键标准。首先，他们必须构成经济损失和/或严重疾病的重大风险。自然感染还必须能够触发保护性免疫和免疫记忆。如前所述，人畜共患寄生虫，例如原生动物Toxoplasma gondii, make attractive candidates for vaccine development. However, whilst vaccinating pigs against toxoplasma would prevent foodborne transmission to humans, it causes few problems in swine and only minor production losses.

The best candidate highlighted in the最近的评论inPorcine Health Management， 可能Cystoisospora suis,a parasitic protist apicomplexan alveolate (just as Toxoplasma), which causes severe neonatal diarrhoea in 2 week old piglets.C. suis在感染的专利阶段，被感染的猪排泄数百万的卵囊会迅速传播，这可能会导致腹泻长达6天。即使在感染过去之后，动物的发展也很差，并且比健康的对应物小得多，并且发病的可能性增加，导致感染的财务损失。

Cystoisospora suis

At birth, the immune system is poorly developed, with piglets lacking the adequate amount of T- and B- cells until around 6 weeks of age. This gives plenty of opportunity for pathogens to grow and multiply.C. suisinfection of young piglets

can not only cause the associated symptoms like neonatal diarrhoea, but it can damage the development of the gut microbiota, increasing risk of bacterial infection and affecting intestinal and immune functions long-term.

但是，2014年研究发现通过高剂量的出生前将怀孕的母猪接种C. suisoocysts, the sow had no clinical signs of infection or oocyst excretion, and the levels of immunoglobulins in their blood and milk provided partial protection for the offspring as well. This would then help protect the piglets during the first few weeks, when their immune system is most vulnerable.

In conclusion,C. suis可能是一个很好的候选人，但是需要对免疫保护机制进行进一步的研究。直到最近，寻找新疫苗候选者一直很昂贵，但是随着技术和高通量筛查技术的新进展，它已经使潜在的寄生虫的快速且具有成本效益的基因组筛选用于靶向。