To attenuate and control the spread of infectious disease, a body of research has been conducted to generate safe vaccines and to continue national-level surveillance. However, understanding on viability and persistence of avian influenza virus (AIV) in infected carcasses, and effective disposal approaches are still limited up to date. Here, using HA test and RT-PCR, we assessed active status of AIV and degradation of viral RNA in collected specimens at different sites and time points. First, AIV infectivity was recovered until day 2, and viral nucleic acids persisted to day 14 and 21 in inorganic and organic samples, respectively, in sealed vials incubated at room temperature. Second, AIV was totally inactivated in all examined specimens, and viral RNA was not detectable at all time points tested at least one month post-infection in AIV-inoculated carcasses buried directly in soil or fiber reinforced plastic (FRP) bin. Lastly, among different burial sites in South Korea, 6 out of 17 sampling sites in Jeonbuk province showed the presence of viral genetic materials, while the rest of the field samples displayed neither the presence of infective AIV nor detectable viral RNA. This study showed a linear relation between time and degradation degree of viral RNA in buried samples suggesting that burial disposal method is effective for the control or at least attenuation of spread of AI infection in infected animals although consistent monitoring is required to verify safety of disposal.

Carcasses of pigs were trench buried using either general soil or mature compost as a cover material and the malodorous substances discharged were observed about a year. With the soil burial method, the speed of decay was shown to be dominantly affected by the ambient air temperature. However the compost burial method’s decaying process took place quickly, even ambient air temperature was dropped; it holds the temperature of 40oC or higher. With the compost burial method, there was a period where, the temperature inside the pig carcasses and the temperature of cover-material layer were strongly reversed. From this discovery, level of decay process could be speculated. With the soil burial method there was a trend when malodorous substances concentration was high, the level of concentration in the cover soil was also tends to be high. However, the compost burial method had different result. When malodorous substances concentration was high the level of concentration in the compost cover layer was observed to be lower. This indicates compost burial method shown to intercept and absorb malodorous substances. Furthermore, the compost burial method appears to be able to contribute to deactivate the pathogens by quickly decompose the carcasses at a high temperature.