![]() Consider the ongoing problems in Indonesia, most recently the suspicious village group of 17 suspected H5N1 cases, whether or not such clusters are in fact avian flu infections: very likely, "Tamiflu blanket" sorts of local treatments are given to those local areas, possibly to hundreds of residents in a village or neighborhood area. Just one more vexing piece of the dauntingly complicated pandemic preparedness puzzle.Īnother problem occurs to me regarding this issue. ![]() But the sheer volume and condensed time frame of a pandemic wave makes this problem of particular interest. Pharmaceuticals in abundance are finding their way into wastewater and even drinking water. (Singer et al., Environmental Health Perspectives) Ongoing seasonal use of Tamiflu in Japan offers opportunities for researchers to assess how much OC enters and persists in the aquatic environment. Additional modeling would be useful to identify localized areas within river catchments that might be prone to high pharmaceutical concentrations in sewage treatment plant effluent. The workgroup members agreed on the following research priorities: a) available data on the ecotoxicology of OE-P and OC should be published b) risk should be assessed for OC-contaminated river water generating OC-resistant viruses in wildfowl c) sewage treatment plant functioning due to microbial inhibition by neuraminidase inhibitors and other antimicrobials used during a pandemic should be investigated and d) realistic worst-case exposure scenarios should be developed. OC in river water might hasten the generation of OC-resistance in wildfowl, but this possibility seems less likely than the potential disruption that could be posed by OC and other pharmaceuticals to the operation of sewage treatment plants. Can OE-P or OC affect the bugs that make a sewage treatment plant work and lead to its failure? There seems to be a plausible argument this could happen but at the moment, no one knows for sure.īased on the identification and risk-ranking of knowledge gaps, the consensus was that oseltamivir ethylester-phosphate (OE-P) and oseltamivir carboxylate (OC) were unlikely to pose an ecotoxicologic hazard to freshwater organisms. The thinking seemed to be that resistance will develop in patients, not birds. My reading of the somewhat optimistic judgment of the attending virologists was that it expressed more wishful thinking that scientific evidence. ![]() The possible promotion of antiviral resistance is a bigger question mark. In particular the ecotolicologic data were sparse, although based on what was known, there were no obvious alarm bells. Could the presence of Tamiflu in coastal or riverine waters contribute to antiviral resistance in aquatic waterfowl who are reservoirs of various influenza virus subtypes, including those like H5N1 that are potential pandemic viruses?Īndrew Singer at the Centre for Ecology and Hydrology in the Oxford raised the issue in 2006 and now he and 39 other scientists have reported on a workshop they held in October 2007 on "Tamiflu and the Environment: Implications of Use under Pandemic Conditions." Not unexpectedly there were more questions than answers. Hence they will make their way readily into the aquatic environment, even after sewage treatment. ![]() Instead both are highly soluble in water. ![]() There is little biotransformation of either OE-P or OC in sewage treatment plants and it doesn't cling to sewage sludge, where it could be segregated. In a pandemic almost all of this could be used in a 9 to 12 week period. The UK has already stockpiled almost 15 million courses of treatment (10 capsules), amounting to 11 metric tons of OE-P. But there's a lot of it out there and it will be taken in high volume and, either in its capsule form or its active form, excreted into the sewer system in massive quantities (discussed here and here in previous posts). Right now the only oral antiviral likely to have any effectiveness in a pandemic is oseltamivir (Tamiflu), although how effective and how long it would retain any effectiveness is in question. If there's an influenza pandemic in the near future all bets are off when it comes to unplanned for consequences. ![]()
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