Cystic echinococcosis: new vaccinal candidates pave the way for promising control programs

Echinococcosis, also called hydatid disease or hydatidosis, is a near-cosmopolitan zoonosis caused by adult and larval stage of tapeworms (Cestodes) belonging to the genus Echinococcus (family Taeniidae). The most widespread type of Echinococcosis is cystic echinococcosis (CE) that is caused by Echinococcus granulosus that has as definitive hosts carnivores. During life cycle E. granulosus also has important intermediate host such as livestock and human. The E. granulosus exists as a complex of different intraspecific variants or strains that have substantial variations at the genetic level, but the most important is the G1 strain (sheep strain) that is the most cosmopolitan form, and it is responsible for most of the global burden of human CE. The greatest prevalence of the disease is in regions of the temperate countries, and this is an endemic disease in some parts of the world, such as South America, North Africa, Asia and Australia, in other parts of the world, such as China, central Asia, Eastern Europe and Israel, this disease is considered an emergence or re-emergence. There are different ways to treat the cystic echinococcosis like: surgical removal of intact hydatid cysts, the treatment with the best potential to remove cysts, chemotherapy using benzimidazole, this medical approach can be recommended for many patients, percutaneous aspiration, injection, re-aspiration (PAIR) is indicated for patients who cannot undergo surgery, who have single or multiple cysts. The problem link to these treatments is that they could produce a lot of different complications to the patients, so they do not represent an efficacious way to control the disease, for this reason the production of a vaccine seems to be an important element to obtain an efficacious control program. Different studies found new vaccinal candidate to produce an efficacious vaccine, one is the recombinant egG1Y162 protein that demonstrates an increase of serum IgG levels in E. granulosus challenged mice, the second candidate was rEGVac, a multi-epitope multi-antigenic recombinant vaccine that comprised three antigens EG95, Eg14-3-3, Enolase efficacious against different of E. granulosus life cycle, the third candidate was the combination of EgA31 and EgG1Y162 proteins, these are composed of several dominant B-cell and T- cell epitopes that pave the way for designing ideal multi-epitope vaccines against E. granulosus. The difficulty to produce an efficacious vaccine is link to the different strains of E. granulosus. However, the new vaccinal candidates pave the way to produce efficacious control programs.