Studies on the duration of immunity induced in cattle after natural FMD infection and post vaccination with bivalent oil vaccine

Abstract

Aim: To detect the proper time for vaccination of infected calves after the onset of clinical signs and revaccination for previously vaccinated animals with bivalent FMD montanide ISA206 inactivated vaccine. Materials and Methods: Twenty calves naturally infected with foot and mouth disease (FMD) showing clinical signs represented by lesions on the tongue, buccal mucosa and feet. Samples were collected from these calves including tongue epithelial and oropharyngeal fluid (OP). The causative virus was isolated from such samples through inoculation of baby mice and typed by indirect Sandwich ELISA and was confirmed in 2 tongue epithelia samples using PCR. Results: The serum antibody titers were determined using SNT and ELISA in the sera of the 20 infected calves revealing that the infected farms should be vaccinated with inactivated bivalent FMD vaccine for (type O and A) Adjuvanted with montanide ISA206 after 32 weeks from the appearance of clinical signs. In addition the FMD immune status was monitored in 2 farms in EL-Fayoum and El-Sharkia Governorates where 50 calves in each farm were vaccinated with the bivalent FMD inactivated vaccine adjuvaned with montanide ISA206 and serum samples were collected monthly from these animals to determine their immune status using SNT and ELISA. The obtained results showed that vaccinated calves with the bivalent FMD montanide ISA206 inactivated vaccine should be revaccinated after 36 weeks post vaccination. Conclusions: naturally infected calves should be vaccinated on the 32 weeks post infection while vaccinated calves should be revaccinated on the 36 weeks post vaccination

Virological and immunological studies on foot and mouth disease virus type SAT2 naturally infected and vaccinated buffalo cows and their calves

“…The isolate was confirmed as FMDV serotype SAT2 using CFT; ELISA and PCR (Table -1). The use of such techniques for isolation; identification and typing of FMDV were recommended by [26,28,10].…”

“…Veronal buffer (8 ml) was added to the homogenized tissues, and chloroform added to the mixture, followed by centrifugation at 7000 rpm for 10 min at 4°C. The supernatant was collected and tested for FMDV presence in tissue culture and mice [10].…”

“…FMDV can be isolated from infected tongue epithelium and esopharyngeal fluid by intrapretonial inoculation of baby mice, where paralysis of the hind limbs of all inoculated mice would suggest positive isolation. Virus identification and serotyping can be done by indirect sandwich enzyme linked immunosorbent assay (ELISA) [10].…”

Interplay of foot and mouth disease virus with cell‐mediated and humoral immunity of host

“…The interval of antibody response in experimentally infected cattle with FMDV persisted for duration of 40 weeks. 47 Mohan et al 48 These findings showed that only IgA antibodies detected at late stages of infection were specific to genuine mucosal responses.…”

“…A rise in serum antibody titer can be detected around 28 days and remains at protective levels thereafter. The interval of antibody response in experimentally infected cattle with FMDV persisted for duration of 40 weeks …”