Duration of Maternally Derived Antibodies against Akabane Virus in Calves: Survival Analysis

Abstract

ABSTRACT. To prevent encephalomyelitis caused by Akabane virus, as observed in 2006, vaccination of calves is one of the most effective prophylactic measures. For vaccination of calves, the duration of the maternal antibodies need to be considered because these antibodies are an obstacle to the effectiveness of the vaccine. In order to estimate the age of antibody decay in calves and to find factors influencing the duration of passive immunity, we conducted survival analysis using data from nationwide sentinel surveillance for Akabane disease. The accelerated failure time model based on the presence of interval censored data was used. The best fit model with a log-logistic distribution indicated that the maternal antibodies of beef calves last 1.11 times longer (95% confidence interval [CI]=1.06-1.16) than those of dairy calves. Calves in the western part of Japan and on Kyushu island, Japan, maintained the maternal antibodies 1.17 times (95% CI=1.11-1.23 and 1.10-1.24, respectively) longer than those in the eastern part of Japan. The ages at which beef calves in the eastern part of Japan, western part of Japan and Kyushu loose the antibodies, with 90% probability, were estimated to be 4.1, 4.8 and 4.8 months, respectively, while the ages were 3.7, 4.3 and 4.3 months for dairy calves in the same regions. The duration of maternal immunity to Akabane virus was different for different types of cattle and among different regions. These differences need to be taken into account when a vaccination strategy is adopted for preventing epizootic encephalomyelitis in the future.KEY WORDS: AFT model, akabane virus, maternal antibody, survival analysis.

Schmallenberg virus antibody persistence in adult cattle after natural infection and decay of maternal antibodies in calves

“…There are sparse reports on the course of decay of maternal antibodies against Orthobunyaviruses in ruminants. Tsutsui et al [10] showed that dairy calves lost their maternally derived antibodies against Akabane virus at an age of approximately 4 months, while Grimstad et al [11] showed that young white-tailed deer lost their maternal antibodies against Jamestown Canyon virus at an age of 5–6 months. Our results seem to be in range with the above-mentioned studies.…”

Schmallenberg Virus Antibodies in Adult Cows and Maternal Antibodies in Calves

“…Tsutsui and colleagues ( 9 ) showed that dairy calves lost their maternally derived antibodies against Akabane virus at ≈4 months of age, and Grimstad and colleagues ( 10 ) showed that young white-tailed deer lost their maternally derived antibodies against Jamestown Canyon virus at 5–6 months of age. Consistent with those findings, our results show that calves lose maternally derived SBV antibodies at ≈6 months of age and can then be effectively vaccinated against SBV.…”

The follow up study after massive outbreak of Akabane and bovine ephemeral fever viruses in Korea

“…Maternally derived antibodies to Akabane vaccine estimated to be decayed around 4.8 months with 90% probability (Tsutsui et al, 2009). Therefore, we categorized as that VN titers from 1:4 to 1:32 (27.0%) and above 1:32 (22.8%) presume respectively positive sera from vaccinated cattle and cattle infected by wild AKAV within positive range.…”