Duration of maternally derived antibodies against equine influenza in newborn foals.

This research focuses on the duration of maternally derived antibodies against equine influenza in newborn foals, indicating that more than half of the studied foals lose their inherited immunity against two strains of equine influenza virus at an early age.

Understanding the research

• The research was centered around the duration and efficacy of maternally derived antibodies against equine influenza in newborn foals.
• These antibodies were measured against two strains of the virus: Influenza A-equi-1 and A-equi-2.
• The study involved a total of 18 foals, and their antibody levels were measured from birth until they were 4 months old.

Findings of the Research

• Results showed that more than half of the foals were seronegative – meaning they lacked sufficient antibodies to fight off infection – to the A-equi-1 virus by the time they were 4 weeks old. The antibody titers, or concentrations, had dropped to 1:16 or lower.
• For the A-equi-2 virus, more than half of the foals were seronegative by the time they were just 2 weeks old, with antibody titers of 1:8 or lower.
• This indicates that the newborn foals lost their inherited immunity against these two strains of equine influenza at a very early age.

Observations on Maternally Derived Antibodies

• Foals born to mares that were recently vaccinated, as well as those not vaccinated within 6 months before giving birth, had low antibody titers against both the influenza A-equi-1 and A-equi-2 viruses.
• This suggests that the passively derived antibodies that newborn foals obtain from their mothers – whether they are recently vaccinated or not – are neither high in concentration nor long-lasting.

Implications of the Research Results

• The study’s findings highlight the need for early and effective vaccination programs for foals against the equine influenza virus.
• The results also suggest that relying solely on maternally derived immunity may be insufficient protection against these viruses for newborn foals, given the rapid decline in antibody levels observed in the study.