Prevalence and genetic characterization of Toxoplasma gondii strains isolated from 31 wild Passeriformes collected in North-Central Oklahoma.

Passerine birds are widely distributed and adapted to various habitats, therefore they are commonly exposed to, and infected with Toxoplasma gondii. The purpose of our project was to determine the prevalence and genotypes of T. gondii in 31 different species of passerines collected as mortalities due to window collisions in North-Central Oklahoma. DNA was extracted from breast tissue and subjected to PCR with primers that amplify a portion of the T. gondii B1 gene. Genotyping was based on a portion of the infected birds based on a multiplex PCR followed by RFLP of 12 T . gondii markers. Of 103 birds comprising 31 species, the overall prevalence (95% confidence interval) of T. gondii infection was 33.0% (24.1‒42.6%). Significant differences in the proportion of T. gondii in birds according to sex or weight were not observed. However, sample sizes of each species were small and prevented a robust analysis of T. gondii according to those biological variables. Genotyping of T. gondii in a subset of 13 infected individuals of 7 species revealed 4 genotypes, according to the Toxoplasma Data Base: #54, #139, #20, and #220. Our results, while hampered by a small sample size for each bird species, suggest that infection with T. gondii in Oklahoma, is common in both migrant and resident passerines.

Most veterinarians treating exotic animals use formularies to select drug dosages without consistently checking their sources.

OBJECTIVE: To assess what information sources veterinarians use to select drug dosages for treating exotic animals and how they implement this information. SAMPLE: 936 veterinarians from Europe, Asia, Australia, Africa, and the Americas. PROCEDURES: An anonymous, online survey was used to collect data on information sources used for dosage decisions by veterinarians treating exotic species. Logistic regression models were built to identify associations between individual characteristics and primary outcomes. RESULTS: Respondents reported their single most common source for establishing drug dosages as formularies (682/936 [72.9%]), followed by scientific journals (96 [10.3%]), other textbooks (68 [7.3%]), colleagues (47 [5.0%]), or continuing education notes (38 [4.1%]). Over two-thirds of the respondents (645, 68.9%) consulted a specific exotic animal formulary for establishing drug dosages in most situations. Of the 936 respondents, 407 (43.5%) reported that they sometimes (318 [34.0%]) or never (89 [9.5%]) checked the source of a dosage in a textbook or a formulary, 503 (55.3%) reported that they sometimes (399 [42.6%]) or never (104 [11.1%]) searched the original publication on a dosage, and 486 (51.9%) reported that they would base their dosage decision on the abstract of an article if they had no access to the full-text. Several respondents' reported characteristics were significant predictors of primary outcomes. CLINICAL RELEVANCE: Considering our findings, we recommend authors of formularies and textbooks should focus on evidence-based information and state clearly when information is anecdotal. Tailored strategies to educate veterinarians treating exotic animals on the importance of primary sources are also recommended.

Embryonic Microglia Derive from Primitive Macrophages and Are Replaced by cmyb-Dependent Definitive Microglia in Zebrafish.

Microglia, the tissue-resident macrophages of the CNS, represent major targets for therapeutic intervention in a wide variety of neurological disorders. Efficient reprogramming protocols to generate microglia-like cells in vitro using patient-derived induced pluripotent stem cells will, however, require a precise understanding of the cellular and molecular events that instruct microglial cell fates. This remains a challenge since the developmental origin of microglia during embryogenesis is controversial. Here, using genetic tracing in zebrafish, we uncover primitive macrophages as the unique source of embryonic microglia. We also demonstrate that this initial population is transient, with primitive microglia later replaced by definitive microglia that persist throughout adulthood. The adult wave originates from cmyb-dependent hematopoietic stem cells. Collectively, our work challenges the prevailing model establishing erythro-myeloid progenitors as the sole and direct microglial precursor and provides further support for the existence of multiple waves of microglia, which originate from distinct hematopoietic precursors.