Increased genetic diversity and immigration after West Nile virus emergence in American crows: No evidence for a genetic bottleneck.

Infectious diseases can cause steep declines in wildlife populations, leading to changes in genetic diversity that may affect the susceptibility of individuals to infection and the overall resilience of populations to pathogen outbreaks. Here, we examine evidence for a genetic bottleneck in a population of American crows (Corvus brachyrhynchos) before and after the emergence of West Nile virus (WNV). More than 50% of marked birds in this population were lost over the 2-year period of the epizootic, representing a 10-fold increase in adult mortality. Using analyses of single-nucleotide polymorphisms (SNPs) and microsatellite markers, we tested for evidence of a genetic bottleneck and compared levels of inbreeding and immigration in the pre- and post-WNV populations. Counter to expectations, genetic diversity (allelic diversity and the number of new alleles) increased after WNV emergence. This was likely due to increases in immigration, as the estimated membership coefficients were lower in the post-WNV population. Simultaneously, however, the frequency of inbreeding appeared to increase: Mean inbreeding coefficients were higher among SNP markers, and heterozygosity-heterozygosity correlations were stronger among microsatellite markers, in the post-WNV population. These results indicate that loss of genetic diversity at the population level is not an inevitable consequence of a population decline, particularly in the presence of gene flow. The changes observed in post-WNV crows could have very different implications for their response to future pathogen risks, potentially making the population as a whole more resilient to a changing pathogen community, while increasing the frequency of inbred individuals with elevated susceptibility to disease.

Apparent inbreeding preference despite inbreeding depression in the American crow.

Although matings between relatives can have negative effects on offspring fitness, apparent inbreeding preference has been reported in a growing number of systems, including those with documented inbreeding depression. Here, we examined evidence for inbreeding depression and inbreeding preference in two populations (Clinton, New York, and Davis, California, USA) of the cooperatively breeding American crow (Corvus brachyrhynchos). We then compared observed inbreeding strategies with theoretical expectations for optimal, adaptive levels of inbreeding, given the inclusive fitness benefits and population-specific magnitude of inbreeding depression. We found that low heterozygosity at a panel of 33 microsatellite markers was associated with low survival probability (fledging success) and low white blood cell counts among offspring in both populations. Despite these costs, our data were more consistent with inbreeding preference than avoidance: The observed heterozygosity among 396 sampled crow offspring was significantly lower than expected if local adults were mating by random chance. This pattern was consistent across a range of spatial scales in both populations. Adaptive levels of inbreeding, given the magnitude of inbreeding depression, were predicted to be very low in the California population, whereas complete disassortative mating was predicted in the New York population. Sexual conflict might have contributed to the apparent absence of inbreeding avoidance in crows. These data add to an increasing number of examples of an "inbreeding paradox," where inbreeding appears to be preferred despite inbreeding depression.

The new diagnostic team.

The National Academy of Medicine (NAM) in the recently issued report Improving Diagnosis in Health Care outlined eight major recommendations to improve the quality and safety of diagnosis. The #1 recommendation was to improve teamwork in the diagnostic process. This is a major departure from the classical approach, where the physician is solely responsible for diagnosis. In the new, patient-centric vision, the core team encompasses the patient, the physician and the associated nursing staff, with each playing an active role in the process. The expanded diagnostic team includes pathologists, radiologists, allied health professionals, medical librarians, and others. We review the roles that each of these team members will need to assume, and suggest "first steps" that each new team member can take to achieve this new dynamic.

Health concerns of Micronesian peoples.

Several states in the United States have been experiencing an influx of migrants from an area of the world that most people have only heard of when learning about the atomic bomb and World War II. This area is the former U.S. Trust Territory of Pacific Islands now called the Freely Associated States. At the end of World War II, the United States took possession of many of these islands and in 1948, the United States formally took over administration of the Marshalls, the Carolines, Palau, and the Northern Marianas islands. Collectively this area is known as Micronesia. Micronesians come from areas that have high prevalence of several communicable diseases and there is growing concern that Micronesian immigrants may enable the spread of infectious disease to the United States from Asia. Data concerning Hansen's disease and tuberculosis support this claim. According to data from the Hawai'i State Department of Health, a 5-year trend examining new cases of tuberculosis in Hawai'i identified that 65 out of 77 new cases came from the Freely Associated States of Micronesia. Presented is an overview of the health concerns and health status of the people from the Federated States of Micronesia.