Botulism is a fatal intoxication caused by botulinum neurotoxins (BoNTs), which are mainly produced by Clostridium botulinum and characterized by flaccid paralysis. The BoNTs C and D are the main serotypes responsible for botulism in animals, including buffaloes. Botulism is one of the leading causes of death in adult ruminants in Brazil due to the high mortality rates, even though botulism in buffaloes is poorly reported and does not reflect the real economic impact of this disease in Brazilian herds. Vaccination is reported as the most important prophylactic measure for botulism control, although there are no specific vaccines commercially available for buffaloes in Brazil. This study aimed to evaluate the humoral immune response of buffalo groups vaccinated with three different concentrations of recombinant proteins (100, 200, and 400 µg) against BoNTs serotypes C and D as well as to compare the groups to each other and with a group vaccinated with a bivalent commercial toxoid. The recombinant vaccine with a concentration of 400 μg of proteins induced the highest titers among the tested vaccines and was proven to be the best choice among the formulations evaluated and should be considered as a potential vaccine against botulism in buffalo.

Botulism is a potentially fatal intoxication caused by botulinum neurotoxins (BoNTs) produced mainly by Clostridium botulinum. Vaccination against BoNT serotypes C and D is the main procedure to control cattle botulism. Current vaccines contain formaldehyde-inactivated native BoNTs, which have a time-consuming production process and pose safety risks. The development of non-toxic recombinant vaccines has helped to overcome these limitations. This study aims to evaluate the humoral immune response generated by cattle immunized with non-purified recombinant fragments of BoNTs C and D. Cattle were vaccinated in a two-dose scheme with 100, 200 and 400 µg of each antigen, with serum sampling on days 0, 56, 120, and 180 after vaccination. Animals who received either 200 or 400 μg of both antigens induced titers higher than the minimum required by the Brazilian ministry of Agriculture, Livestock and Food Supply and achieved 100% (8/8) seroconversion rate. Animals vaccinated with commercial toxoid vaccine had only a 75% (6/8) seroconversion rate for both toxins. Animals that received doses containing 400 µg of recombinant protein were the only ones to maintain titers above the required level up until day 120 post-vaccination, and to achieve 100% (8/8) seroconversion for both toxins. In conclusion, 400 µg the recombinant Escherichia coli cell lysates supernatant was demonstrated to be an affordable means of producing an effective and safe botulism vaccine for cattle.

Toxocariasis is a neglected zoonosis that affects children and adults. Recombinant proteins have been widely investigated for diagnosis, achieving high sensitivity and specificity in an overall population; however, little is known about age as a factor in its application. This study aims to investigate the diagnostic potential of Toxocara canis TES-30 and TES-120 recombinant proteins in humans, differentiating between its performance in children and adults. Serum samples collected from children and adults seropositive to Toxocara spp. were tested with indirect ELISA using T. canis TES-30 and TES-120 recombinant proteins produced in Escherichia coli. While rTES-30 sensitivity was not affected by age (81.8% in children and 87% in adults), rTES-120 sensitivity severely decreased in children to only 63.6%, down from 95.7% in adults. Furthermore, the sensitivity of rTES-30 increased to 97.8% after Western blotting confirmation. High specificity (>94%) against other geohelminths was reported for both recombinant proteins. Our study favors the use of rTES-30 with total IgG as the primary antibody in an indirect ELISA assay as a tool for epidemiological human studies.

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