Seroepidemiological Studies of Aino Virus Infection in Korean Cattle

Aino virus infection is characterized by abortion, stillbirth, and congenital abnormalities such as arthropgryposis-hydranencephaly syndrome in calves. In Korea, Aino virus infection was first reported in 1997 by researchers who were investigating the cause of newborn calf deformities. Given the incidence of Aino-related deformities, the need for a study of the Aino virus infection status in Korea was recognized. In this study, we investigated the nationwide seroepidemiological status of Aino virus infection. A total of 9,921 serum samples collected between 1993 and 2001, and 23,760 serum samples between 2002 and 2007 were tested using a virus neutralization assay. The seroprevalence of Aino virus was 73.1, 63.8, 44.9, 56.0, 38.5, 28.4 18.3, 19.6, and 23.2%, respectively, between 1993 and 2001, and 43.8, 42.9, 50.7, 55.3, 31.4, and 25.4%, respectively, between 2002 and 2007. Aino virus infection does not pose a major threat to the bovine industry in Korea till now. The future prospects for Aino virus infection in cattle, however, may change with the global warming phenomena. The results of this study may serve as a basis for future epidemiological studies on Aino virus infection.

Monitoring of Five Bovine Arboviral Diseases Transmitted by Arthropod Vectors in Korea

A survey was performed in Korea to monitor the prevalence of five bovine arboviruses [Akabane virus, Aino virus, Chuzan virus, bovine ephemeral fever (BEF) virus, and Ibaraki virus] in arthropod vectors, such as Culicoides species. To determine the possible applications of survey data in annual monitoring and warning systems in Korea, we examined the prevalence of bovine arboviruses in arthropod vectors using RT-PCR. To compare the sensitivity and specificity of virus detection, nested PCR was also performed in parallel for all five viruses. Using the RT-PCR, the detection limits were at least up to 10(1.5), 10(2.8), 10(2.0), 10(1.8), and 10(4.0) TCID50/ml for Akabane virus, Aino virus, Chuzan virus, BEF virus, and Ibaraki virus, respectively. When nested PCR was performed using 1 micronl of PCR product, the detection limits were increased, to 10(0.05), 10(1.8), 10(1.0), 10(0.008), and 10(2.0) TCID50/ml for Akabane virus, Aino virus, Chuzan virus, BEF virus, and Ibaraki virus, respectively. Thus, nested PCR increased the sensitivity of the virus detection limit by 1~2 log. We pooled 30~40 mosquitoes in one sample. We collected 113 samples in 2006, 135 samples in 2007, and 100 samples in 2008. Among these samples, Chuzan virus and BEF virus genes were detected at a range between 0.82% and 1.19%, and Akabane virus, Aino virus, and Ibaraki virus genes were detected at less than 0.20%. These data may provide some insight into future epidemiological studies of bovine arboviral diseases in Korea.