Mai Thi, N. | Search bioRxiv

bioRxiv2024

Development of a simple and highly sensitive method for the concentration and detection of African swine fever virus in oral fluids and its feasibility assessment on raised pigs in Northern Vietnam

BackgroundEarly detection and early slaughter through quarantine are essential to prevent the spread of the African swine fever virus (ASFV). Highly accurate testing is effective for early detection, but it is still difficult to establish a system, especially in the Global South. Pooled oral fluids tests have been used for simple pathogen monitoring, but compared to blood tests, the virus concentration in oral fluids is low, resulting in false negative and missing true positive cases. We collected oral fluids from raised pigs in northern Vietnam and attempted a highly sensitive ASFV survey using a newly developed virus concentration and detection method. ResultsIn a spike test, the developed method showed up to 100 times greater sensitivity than a reference method. To compare and evaluate the performance of the developed method, a total of 68 pooled oral fluid samples were collected, 63 from northern Vietnam and 5 from southern Japan. Using real-time PCR, 9/68 (13.2%) were positive by the reference method, and 23/68 (33.8%) by the developed method. Using real-time LAMP, 1/68 (1.5%) were positive by the reference method and 6/68 (8.8%) by the developed method. ConclusionsThe developed method improved the sensitivity of ASFV detection from oral fluids and enabled early diagnosis of pigs before the onset of the disease. The developed method has the potential to enable simple and highly sensitive diagnosis of ASF, which is essential for its early diagnosis and effective surveillance. HighlightO_LIA method has been developed to detect ASFV in pig oral fluids with up to 100 times greater sensitivity than a reference method. C_LIO_LIThe developed method combines innovative pretreatment in less than 60 min with conventional nucleic acid extraction with a column kit followed by real-time PCR or LAMP. C_LIO_LIApplied to feasibility assessment for ASF diagnosis on raised pigs, the developed method showed higher diagnostic sensitivity than the reference method. C_LIO_LIThe developed method can be a useful tool that contributes to early detection and surveillance of ASFV. C_LI

microbiology↗

bioRxiv2018

Identification of meteorological factors affecting migration of wild birds into miyazaki and its relation to circulation of highly pathogenic avian influenza virus

Aim of our study is to establish models for predicting the number of migratory wild birds based on the meteorological data. From 136 species of wild birds, which have been observed at Futatsudate in Miyazaki, Japan, from 2008 to 2016, we selected the potential high-risk species, which can introduce highly pathogenic avian influenza (HPAI) virus into Miyazaki; we defined them as \"risky birds\". We then performed regression analysis to model the relationship between the number of risky birds and meteorological data. We selected 10 wild bird species as risky birds: Mallard (Anas platyrhynchos), Northern pintail (Anas acuta), Eurasian wigeon (Anas penelope), Eurasian teal (Anas crecca), Common pochard (Aythya ferina), Eurasian coot (Fulica atra), Northern shoveler (Anas clypeata), Common shelduck (Tadorna tadorna), Tufted duck (Aythya fuligula), and Herring gull (Larus argentatus). We succeeded in identifying five meteorological factors associated with their migration: station pressure, mean value of global solar radiation, minimum of daily maximum temperature, days with thundering, and days with daily hours of daylight under 0.1 h. We could establish some models for predicting the number of risky birds based only on the published meteorological data, without manual counting. Dynamics of migratory wild birds has relevance to the risk of HPAI outbreak, so our data could contribute to save the cost and time in strengthening preventive measures against the epidemics.

epidemiology↗