Effects of Main-Stem Impoundments on Hydrology and Larval Fish Communities in Major Tributaries of Two Large Midwestern Rivers

Anthropogenic modifications, like impoundments, have altered natural environmental conditions in most lotic systems and impacted fish ecology in many ways. We examined the effect of large river impoundments on fish reproductive behavior by studying the larval fish communities in tributaries of the impounded Illinois and unimpounded Wabash Rivers. We hypothesized that larval fish communities would be similar between the geographically proximal systems, but temporal structuring would depend largely on flow regimes. Biweekly larval densities were greatest among all taxa in the Wabash system, though overall communities were similar between systems. Of the six tributaries, the four smallest rivers were most similar in assemblage structure, and the two largest tributaries were more diverse. All tributaries demonstrated larval community shifts from spring to summer, but Illinois River tributaries exhibited greater temporal variability. The large rivers had distinctive hydrographs, with differences in peak amplitude, duration, timing, and rate of water level change. Regulation of flow on the Illinois River was shown to mediate river fluctuations in its tributaries. Consequently, fish that depend on high water events for spawning in tributaries may not receive a strong cue in Illinois River tributaries and instead spawn in the Illinois River. Subsequently, larval production in large, impounded lotic systems may be concentrated in the larger rivers of these systems, and more evenly distributed among rivers in free-flowing systems

Effects of Main-Stem Impoundments on Hydrology and Larval Fish Communities in Major Tributaries of Two Large Midwestern Rivers

Anthropogenic modifications, like impoundments, have altered natural environmental conditions in most lotic systems and impacted fish ecology in many ways. We examined the effect of large river impoundments on fish reproductive behavior by studying the larval fish communities in tributaries of the impounded Illinois and unimpounded Wabash Rivers. We hypothesized that larval fish communities would be similar between the geographically proximal systems, but temporal structuring would depend largely on flow regimes. Biweekly larval densities were greatest among all taxa in the Wabash system, though overall communities were similar between systems. Of the six tributaries, the four smallest rivers were most similar in assemblage structure, and the two largest tributaries were more diverse. All tributaries demonstrated larval community shifts from spring to summer, but Illinois River tributaries exhibited greater temporal variability. The large rivers had distinctive hydrographs, with differences in peak amplitude, duration, timing, and rate of water level change. Regulation of flow on the Illinois River was shown to mediate river fluctuations in its tributaries. Consequently, fish that depend on high water events for spawning in tributaries may not receive a strong cue in Illinois River tributaries and instead spawn in the Illinois River. Subsequently, larval production in large, impounded lotic systems may be concentrated in the larger rivers of these systems, and more evenly distributed among rivers in free-flowing systems

US Centers for Disease Control and Prevention and Its Partners’ Contributions to Global Health Security

To achieve compliance with the revised World Health Organization International Health Regulations (IHR 2005), countries must be able to rapidly prevent, detect, and respond to public health threats. Most nations, however, remain unprepared to manage and control complex health emergencies, whether due to natural disasters, emerging infectious disease outbreaks, or the inadvertent or intentional release of highly pathogenic organisms. The US Centers for Disease Control and Prevention (CDC) works with countries and partners to build and strengthen global health security preparedness so they can quickly respond to public health crises. This report highlights selected CDC global health protection platform accomplishments that help mitigate global health threats and build core, cross-cutting capacity to identify and contain disease outbreaks at their source. CDC contributions support country efforts to achieve IHR 2005 compliance, contribute to the international framework for countering infectious disease crises, and enhance health security for Americans and populations around the world

COVID-19 Case Investigations Among Federally Quarantined Evacuees From Wuhan, China, and Exposed Personnel at a US Military Base, United States, February 5-21, 2020

In February 2020, during the early days of the COVID-19 pandemic, 232 evacuees from Wuhan, China, were placed under federal 14-day quarantine upon arrival at a US military base in San Diego, California. We describe the monitoring of evacuees and responders for symptoms of COVID-19, case and contact investigations, infection control procedures, and lessons learned to inform future quarantine protocols for evacuated people from a hot spot resulting from a novel pathogen. Thirteen (5.6%) evacuees had COVID-19-compatible symptoms and 2 (0.9%) had laboratory-confirmed SARS-CoV-2. Two case investigations identified 43 contacts; 3 (7.0%) contacts had symptoms but tested negative for SARS-CoV-2 infection. Daily symptom and temperature screening of evacuees and enacted infection control procedures resulted in rapid case identification and isolation and no detected secondary transmission among evacuees or responders. Lessons learned highlight the challenges associated with public health response to a novel pathogen and the evolution of mitigation strategies as knowledge of the pathogen evolves