Vaccines for gastrointestinal parasites, a pillar of preventive medicine in veterinary practice: Systematic review

Contextualization: The antiparasitic resistance caused by the indiscriminate use of anthelmintic drugs for the control of gastrointestinal parasites in production animals and pets, has become one of the biggest problems in animal health. For this reason, the use of vaccines could benefit animal health and welfare by controlling emerging zoonotic diseases and foodborne pathogens of animal origin, thus improving public health. Knowledge gap: It is relevant for professionals in veterinary science to know the clinical trials of experimental vaccines for controlling certain gastrointestinal parasites.   This way, they can be at the forefront of the next available technological products and so, be able to control this menace to the animal health and public health.  Purpose: To do a systematic review of clinical trials for experimental vaccines in production animals and pets for diseases caused by gastrointestinal parasites of relevance in animal production and/or public health. Furthermore, it presents the current gastrointestinal antiparasitic vaccines commercialized in different countries and their prophylactic efficacy. Methodology: PRISMA protocols were followed for this systematic review. Articles were obtained from scientific databases with the following keywords: vaccines, clinical trials, commercial vaccines, parasites control, gastrointestinal nematodes, gastrointestinal cestodes, gastrointestinal protozoa, Ascaris suum, Ancylostoma caninum, Cooperia oncophora, Echinococcus granulosus, Eimeria spp., Giardia lamblia, Haemonchus contortus, Osteortagia osteortagi, Taenia solium and Teladorsagia circumcincta.  Only clinical trials of gastrointestinal antiparasitic vaccines in birds, pets, pigs and ruminants were included in this analysis, as well as commercial vaccines currently available for these same parasites.  Results and conclusions: Even though there are important clinical trial studies of vaccines in these animal species (n=101) reported between 1964 to 2020, only five parasites can be prevented/controlled with commercial vaccines used in veterinary medicine: Haemonchus contortus and Echinococcus granulosus in ruminants, Taenia solium in pigs, Eimeria spp. in birds and Giardia lamblia in dogs (e.g., Cysvax™, Barbervax®, Providean® Hidatil EG95, CocciVac® and GiardiaVax™). It is expected that, with the development of bioinformatics and methodologies such as reverse vaccinology, this immunoprophylactic and immunotherapeutic range will be extended as to control these parasitic agents of great importance in human and animal health.