A New Cage-Like Particle Adjuvant Enhances Protection of Foot-and-Mouth Disease Vaccine.

Foot-and-Mouth Disease (FMD) is an acute viral disease that causes important economy losses. Vaccines with new low-cost adjuvants that stimulate protective immune responses are needed and can be assayed in a mouse model to predict their effectiveness in cattle. Immunostimulant Particle Adjuvant (ISPA), also known as cage-like particle adjuvant, consisting of lipid boxes of dipalmitoyl-phosphatidylcholine, cholesterol, sterylamine, alpha-tocopherol, and QuilA saponin, was shown to enhance protection of a recombinant vaccine against Trypanosoma cruzi in a mouse model. Thus, in the present work, we studied the effects on the magnitude and type of immunity elicited in mice and cattle in response to a vaccine based on inactivated FMD virus (iFMDV) formulated with ISPA. It was demonstrated that iFMDV-ISPA induced protection in mice against challenge and elicited a specific antibody response in sera, characterized by a balanced Th1/Th2 profile. In cattle, the antibody titers reached corresponded to an expected percentage of protection (EPP) higher than 80%. EPP calculates the probability that livestock would be protected against a 10,000 bovine infectious doses challenge after vaccination. Moreover, in comparison with the non-adjuvanted iFMDV vaccine, iFMDV-ISPA elicited an increased specific T-cell response against the virus, including higher interferon gamma (IFNγ)+/CD8+ lymphocyte production in cattle. In this work, we report for first time that an inactivated FMDV serotype A vaccine adjuvanted with ISPA is capable of inducing protection against challenge in a murine model and of improving the specific immune responses against the virus in cattle.

Short communication: Relationship between the level of bovine leukemia virus antibody and provirus in blood and milk of cows from a naturally infected herd.

We explored the relationship between the level of bovine leukemia virus antibodies and provirus load during natural infection. For that purpose, a set of 50 blood and milk paired samples were analyzed for the presence of bovine leukemia virus provirus and antibodies. Additionally, provirus load and antibody titers were measured and the relationship between these variables was investigated. Bovine leukemia provirus was detected in 59% of milk samples and a negative correlation was observed between the level of milk provirus load and milk antibody titers. By the consumption of raw milk, calves might be exposed to bovine leukemia virus favoring the perinatal transmission of this disease.

Molecular characterization of Cryptosporidium isolates from calves in Argentina.

Cryptosporidiosis is responsible for significant fatalities of neonatal calves, resulting in substantial economic loss in dairy farming in several countries. Additionally, the high shedding of environmentally resistant oocysts by calves promotes contamination of drinking water and facilitates outbreaks of cryptosporidiosis in humans. Here we report on the Cryptosporidium species and GP60 subtypes of 45 calves originating from the Humid Pampa, the main productive dairy farming area of Argentina. Polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) analysis of the 18S rRNA gene was done to determine the infecting Cryptosporidium species and only Cryptosporidium parvum was detected. Subtyping by sequence analysis of the GP60 gene revealed 6 different alleles all pertaining to the zoonotic IIa family. Of these, IIaA23G1R1 represents a novel IIa subtype. Other identified subtypes, IIa18G1R1, IIaA20G1R1, IIaA21G1R1, and IIaA22G1R1 have been recognized in very few studies and/or with low frequencies. Interestingly, different alleles prevailed in the provinces of Buenos Aires (IIaA17G1R1 and IIaA21G1R1), Santa Fe (IIaA23G1R1), and Cordoba (IIaA20G1R1 and IIaA21G1R1), and different allele distribution patterns were observed. Subtypes IIaA18G1R1 and IIaA17G1R1, the latter often found in this study, are strongly implicated in zoonotic transmission, suggesting that calves may represent a potential source for human cryptosporidiosis in this region. This is the first published report of a molecular analysis of Cryptosporidium infection in dairy and beef calves from Argentina.