Five active hypotheses span dairy cattle semen transmission, Cambodia case trajectory, Nepal-India human spillover, and Pacific pinniped expansion. This cycle's evidence is limited to vaccine research publications (rabies-vectored H5N1 vaccine, seasonal flu cross-protection) with no new operational case signals. The semen-mediated transmission hypothesis resolves Apr 28 — no confirmation or refutation has appeared in the available evidence window.

PubMed returned two relevant articles (Apr 15–17): a rabies-based H5N1 vaccine immunogenicity study and a cross-protection analysis from seasonal influenza vaccines — both neutral to the active hypotheses. WHO DON returned a measles Americas update (irrelevant). ProMED is failing (44% ok ratio, pending status). PubMed is stale at 10.6% ok ratio, the stalest active connector. GenBank and genomic-surveillance remain inactive.

The short-fuse hypothesis (hyp:h5n1:2026-09-30:41bbd71fcd, resolves Apr 28) on H5N1 semen/venereal transmission confirmation in dairy cattle has no corroborating incoming data. The Cambodia hypothesis (hyp:h5n1:2026-12-31:4b28b4edbe, conf 6) was registered Apr 22 and reflects YTD count of 4 cases vs threshold of 8. Nepal-India corridor (hyp:h5n1:2026-09-30:878aaead5f, conf 4) and pinniped expansion (hyp:h5n1:2026-09-30:1a242aed2d, conf 6) are unchanged — no new WHO DON or WOAH signals this cycle.

Connector issues materially degrade this cycle. PubMed (10.6% ok) has been failing since Apr 22 with timeout errors; ProMED (44.4% ok) is pending/failing. WOAH-WAHIS, GISAID, and genomic-surveillance are inactive. This leaves WHO DON, Africa CDC, CDC MMWR, and PAHO as the operational feed — none produced H5N1-specific content today.

Hypothesis-specific assessment:

• Semen transmission (Apr 28 resolution): Three-state USDA detection in dairy cattle semen (Idaho, South Dakota, Arkansas) documented in prior cycle. No follow-up USDA experimental or epidemiological study has appeared in the evidence stream. Resolution is imminent and will likely remain ambiguous at this cycle.
• Cambodia YTD ≥8 (Dec 31): 4 cases as of Apr 22; 4 additional cases needed over 8+ months. Clade 2.3.2.1c poultry reservoir in rural provinces is the standing assumption. No new Cambodia MoH or WHO signals this cycle.
• Nepal-India corridor spillover: Multi-district poultry spread documented in prior cycle. No human case confirmed. Confidence remains at 4.
• Pinniped expansion: California elephant seal outbreak remains the baseline. No new marine mammal case reported.
• Vaccine research (rabies-vectored platform, seasonal cross-protection): relevant for pandemic preparedness but neutral to all five hypotheses.