The seroprevalence of Japanese encephalitis virus (JEV) among equines was evaluated from January 2006 to December 2009 in 13 different states of India by hemagglutination inhibition (HI) test and virus neutralization test (VNT). Antibodies against JEV were detected in 327 out of 3,286 (10%) equines with a maximum prevalence reported in the state of Manipur (91.7%) followed by Gujarat (18.5%), Madhya Pradesh (14.4%), and Uttar Pradesh (11.6%). Evidence of JEV infection was observed in equines in Indore (Madhya Pradesh) where a 4-fold or higher rise in antibody titer was observed in 21 out of 34 horses in November 2007 to October 2006. In March 2008, seven of these horses had a subsequent 4-fold rise in JEV antibody titers while this titer decreased in nine animals. JEV-positive horse sera had a JEV/WNV (West Nile virus) ratio over 2.0 according to the HI and/or VNT. These results indicated that JEV is endemic among equines in India.
Animals ; Encephalitis, Japanese/blood/epidemiology/*veterinary ; *Equidae ; India/epidemiology ; Neutralization Tests ; Seroepidemiologic Studies ; Time Factors

Japanese encephalitis virus (JEV) causes a mosquitoborne viral zoonosis that is becoming increasingly important to public health in east and south Asia. Although JEV is primarily associated with reproductive failure in swine, JEV infection can cause fever and headache in humans and is associated with aseptic meningitis and encephalitis. The exact mode of transmission, including host range and possible source of viral amplification within livestock, is still not completely clear. This study consisted of a serological survey of JEV infection in goats. A total of 804 goat serum samples were collected from 144 farms in Korea between May 2005 and May 2006. The incidence of positive cases was 12.1% (97 out of 804 goats). The seroprevalence of JEV infection in the 144 farms screened was 31.3% (45/144), indicating that JEV infection is frequent in goat farms in Korea. In addition, three districts of Korea (mainly in the southern region) had a higher seroprevalence of JEV compared to other areas. The results suggest that goats could be monitored epidemiologically as a sentinel animal for JEV transmission in Korea.
Age Factors ; Animals ; Antibodies, Viral/blood ; Encephalitis Virus, Japanese/*isolation & purification ; Encephalitis, Japanese/epidemiology/*veterinary/virology ; Goat Diseases/*epidemiology/*virology ; Goats ; Hemagglutination Inhibition Tests/veterinary ; Korea/epidemiology ; Seroepidemiologic Studies

Climate change induced by recent global warming may have a significant impact on vector-borne and zoonotic diseases. For example, the distribution of Japanese encephalitis virus (JEV) has expanded into new regions. We surveyed the levels of hemagglutination-inhibition (HI) antibodies against JEV (Family Flaviviridae, genus Flavivirus) in wild birds captured in Korea. Blood samples were collected from 1,316 wild birds including the following migratory birds: Oceanodroma castro (n = 4), Anas formosa (n = 7), Anas penelope (n = 20), Fulica atra (n = 30), Anas acuta (n = 89), Anas crecca (n = 154), Anas platyrhynchos (n = 214), Aix galericulata (n = 310), and Anas poecilorhyncha (n = 488). All were captured in 16 locations in several Korea provinces between April 2007 and December 2009. Out of the 1,316 serum samples tested, 1,141 (86.7%) were positive for JEV. Wild birds captured in 2009 had a higher seroprevalence of ant-JEV antibodies than those captured in 2007. Wild birds with an HI antibody titer of 1 : 1,280 or higher accounted for 21.2% (280/1,316) of the animals tested. These findings indicated that wild birds from the region examined in our study have been exposed to JEV and may pose a high risk for introducing a new JEV genotype into Korea.
Animal Migration ; Animals ; Animals, Wild ; Bird Diseases/*epidemiology/virology ; Birds ; Encephalitis Virus, Japanese/genetics/*isolation & purification ; Encephalitis, Japanese/blood/epidemiology/*veterinary/virology ; Genotype ; Hemagglutination Inhibition Tests ; Population Surveillance ; Republic of Korea/epidemiology ; Seroepidemiologic Studies

Recent global warming trends may have a significant impact on vector-borne viral diseases, possibly affecting vector population dynamics and disease transmission. This study measured levels of hemagglutination-inhibition (HI) antibodies against Japanese encephalitis virus (JEV) and neutralizing antibodies against Akabane virus (AKAV) and Aino virus (AINV) for Thoroughbred horses in Korea. Blood samples were collected from 989 racehorses in several provinces, between October 2005 and March 2007. Sera were tested using either an HI assay or a virus neutralization test. Approximately half (49.7%; 492/989) of the horses tested were antibody-positive for JEV. The HI titer against JEV was significantly correlated with racehorse age (p < 0.05). Horses with an HI antibody titer of 1: 160 or higher accounted for 3.9% of the animals tested, indicating that vectors transmitting arthropod- borne viruses bit relatively few horses. In contrast, 3.8% (19/497) and 19.5% (97/497) of horse sera collected in March 2007 were positive against AKAV and AINV, respectively. The presence of antibodies against AKAV and AINV may indicate the multiplication of AKAV and AINV in these horses.
Aging ; Animals ; Encephalitis Virus, Japanese/*isolation & purification ; Hemagglutination Inhibition Tests/veterinary ; Horse Diseases/blood/*epidemiology ; Horses ; Korea/epidemiology ; Orthobunyavirus/*isolation & purification ; Seroepidemiologic Studies

Vector-borne arboviruses produce mild to severe symptoms in domestic animals. Bovine ephemeral fever (BEF), Akabane, Aino, and Chuzan virus have been primarily attributed to reproductive disorders or febrile diseases in cattle, and Japanese encephalitis virus (JEV) is mainly associated with reproductive failures in swine. We investigated antibody titers from domestic swine against four bovine arboviruses (BEF, Akabane, Aino, and Chuzan virus) and from cattle against JEV in Korea. While the positive rates for Akabane and BEF were 37.4% and 15.7%, the positive incidence of Chuzan and Aino were relatively low, with positive rates of 3.04% and 0.4%, respectively, based on a virus neutralization assay. Antibody titers against more than one virus were also frequently detected in domestic swine. The incidence of JEV was 51.3% among domestic cattle. In addition, one positive case was detected in the thoracic fluids from 35 aborted calves, based on the hemagglutination inhibition test. Our results indicate that swine are susceptible hosts of bovine arboviruses without showing clinical symptoms in a natural environment. Moreover, we confirmed that JEV could be associated with reproductive failure in pregnant cattle, as were other vector-borne bovine arboviruses assessed in this study.
Animals ; Antibodies, Viral/blood ; Cattle ; Cattle Diseases/*epidemiology/*virology ; Encephalitis Virus, Japanese/*immunology ; Encephalitis, Japanese/blood/epidemiology/*veterinary/virology ; Ephemeral Fever/blood/*epidemiology/virology ; Ephemeral Fever Virus, Bovine/*immunology ; Hemagglutination Tests ; Incidence ; Korea/epidemiology ; Neutralization Tests ; Swine ; Swine Diseases/*epidemiology/*virology