Filter-feeding bivalves can remove avian influenza viruses from water and reduce infectivity

Abstract

Avian influenza (AI) viruses are believed to be transmitted within wild aquatic bird populations through an indirect faecal -oral route involving contaminated water. This study examined the influence of filterfeeding bivalves, Corbicula fluminea, on the infectivity of AI virus in water. Clams were placed into individual flasks with distilled water inoculated 1 : 100 with a low pathogenic (LP) AI virus (A/Mallard/MN/190/99 (H3N8)). Viral titres in water with clams were significantly lower at 24 and 48 h post-inoculation compared to LPAI-infected water without clams. To determine whether clams affected the infectivity of AI viruses, 18 wood ducks (Aix sponsa) were divided into test groups and inoculated with a variety of treatments of clam supernatants, whole clams and water exposed to a high pathogenic (HP) AI (A/whooper swan/Mongolia/244/05 (H5N1)). None of the wood ducks inoculated with HPAI-infected water that was filtered by clams or that was inoculated with or fed tissue from these clams exhibited morbidity or mortality. All wood ducks exposed to either HPAI-infected water without clams or the original viral inoculum died. These results indicate that filter-feeding bivalves can remove and reduce the infectivity of AI viruses in water and demonstrate the need to examine biotic environmental factors that can influence AI virus transmission.

Accumulation and Inactivation of Avian Influenza Virus by the Filter-Feeding Invertebrate Daphnia magna

“…Results from laboratory studies that exposed filter-feeding invertebrates to AIV range from complete depletion of the virus by clams (18) to accumulation of viable virus for more than 2 weeks in zebra mussels (19). Daphnia in our study rapidly reduced AIV concentrations in the water.…”

“…Therefore, it is plausible that aquatic filter-feeding invertebrates, an important source of food to a number of waterfowl species, may play a role as an intermediate vector and facilitate transmission of AIV. In the first test of this hypothesis, Faust et al (18) exposed Asiatic clams (Corbicula fluminea) to AIV-dosed water and documented dramatic reductions in AIV concentrations in the water and reduced viral infectivity associated with the filtering behavior of the bivalves. In contrast, zebra mussels (Dreissena polymorpha) maintained detectable amounts of viable AIV in their tissue for up to 16 days postexposure (19), and freshwater clams acted as bioconcentrators for AIV, highlighting their potential use as sentinels in AIV surveillance (20).…”

Removal of enteric viruses and Escherichia coli from municipal treated effluent by zebra mussels

“…However, only a few studies were related to viruses. A reduced viral infectivity was shown in wood ducks (Aix sponsa) inoculated intranasally with water spiked with avian influenza virus, previously filtered by Corbicula fluminea (Faust et al, 2009), which allowed bird survival. It was also demonstrated that zebra mussels could accumulate avian influenza virus from wastewaters for an extended period (Stumpf et al, 2010), after which the virus was still detectable inside the mussels even after transfer to freshwater.…”

“…Escherichia coli removal by oysters and hard shell clams (Love et al, 2010) as well as by common mussels (de Mesquita et al, 1991) has also been studied, and oysters or hard shell clams were also used for norovirus (Flannery et al, 2013), poliovirus, hepatitis A (Love et al, 2010) or Norvalk virus removal (Schwab et al, 1998). However, to our knowledge, the accumulation of human health-related enteric viruses by zebra mussels from water was never described, the only one case referring to avian influenza virus (Faust et al, 2009).…”

Failure of Transmission of Low-Pathogenic Avian Influenza Virus Between Mallards and Freshwater Snails: An Experimental Evaluation

“…Zebra mussels (Dreissena polymorpha) bioaccumulated and maintained infectious AI virus (low pathogenic H5N1) in their tissues for 14 days (Stumpf et al, 2010). Similarly, Asiatic clams (Corbicula fluminea) bioaccumulated LPAI viruses in their tissues (Faust et al, 2009;Huyvaert et al, 2012), but ingestion of the tissues failed to transmit AI virus to Wood Ducks (Aix sponsa; Faust et al, 2009). No investigators have examined the potential role of aquatic snails in AI virus persistence and transmission via ingestion of infected invertebrates.…”