A novel apicomplexan parasite was serendipitously discovered in horses at the United States - Mexico border. Phylogenetic analysis based on 18S rDNA showed the erythrocyte-infective parasite to be related to, but distinct from, Theileria spp. in Africa, the most similar taxa being Theileria spp. from waterbuck and mountain zebra. The degree of sequence variability observed at the 18S rDNA locus also suggests the likely existence of additional cryptic species. Among described species, the genome of this novel equid Theileria parasite is most similar to that of Theileria equi, also a pathogen of horses. The estimated divergence time between the new Theileria sp. and T. equi, based on genomic sequence data, is greater than 33 million years. Average protein sequence divergence between them, at 23%, is greater than that of Theileria parva and Theileria annulata proteins, which is 18%. The latter two represent highly virulent Theileria spp. of domestic cattle, as well as of African and Asian wild buffalo, respectively, which differ markedly in pathology, host cell tropism, tick vector and geographical distribution. The extent of genome-wide sequence divergence, as well as significant morphological differences, relative to T. equi justify the classification of Theileria sp. as a new taxon. Despite the overall genomic divergence, the nine member equi merozoite antigen (EMA) superfamily, previously found as a multigene family only in T. equi, is also present in the novel parasite. Practically, significant sequence divergence in antigenic loci resulted in this undescribed Theileria sp. not being detectable using currently available diagnostic tests. Discovery of this novel species infective to equids highlights exceptional diversity within the genus Theileria, a finding with serious implications for apicomplexan parasite surveillance.

The intensity mapping of Lyα emission during the epoch of reionization (EoR) will be contaminated by foreground emission lines from lower redshifts. We calculate the mean intensity and the power spectrum of Lyα emission at z ∼ 7, and estimate the uncertainties according to the relevant astrophysical processes. We find that the low-redshift emission lines from 6563Å Hα, 5007Å [OIII] and 3727Å [OII] will be strong contaminants on the observed Lyα power spectrum. We make use of both the star formation rate (SFR) and luminosity functions (LF) to estimate the mean intensity and power spectra of the three foreground lines at z ∼ 0.5 for Hα, z ∼ 0.9 for [OIII] and z ∼ 1.6 for [OII], as they will contaminate the Lyα emission at z ∼ 7. The [OII] line is found to be the strongest. We analyze the masking of the bright survey pixels with a foreground line above some line intensity threshold as a way to reduce the contamination in an intensity mapping survey. We find that the foreground contamination can be neglected if we remove pixels with fluxes above 1.4 × 10 −20 W/m 2 .

Background Anaphylaxis, which is rare, has been reported after COVID‐19 vaccination, but its management is not standardized. Method Members of the European Network for Drug Allergy and the European Academy of Allergy and Clinical Immunology interested in drug allergy participated in an online questionnaire on pre‐vaccination screening and management of allergic reactions to COVID‐19 vaccines, and literature was analysed. Results No death due to anaphylaxis to COVID‐19 vaccines has been confirmed in scientific literature. Potential allergens, polyethylene glycol (PEG), polysorbate and tromethamine are excipients. The authors propose allergy evaluation of persons with the following histories: 1—anaphylaxis to injectable drug or vaccine containing PEG or derivatives; 2—anaphylaxis to oral/topical PEG containing products; 3—recurrent anaphylaxis of unknown cause; 4—suspected or confirmed allergy to any mRNA vaccine; and 5—confirmed allergy to PEG or derivatives. We recommend a prick‐to‐prick skin test with the left‐over solution in the suspected vaccine vial to avoid waste. Prick test panel should include PEG 4000 or 3500, PEG 2000 and polysorbate 80. The value of in vitro test is arguable. Conclusions These recommendations will lead to a better knowledge of the management and mechanisms involved in anaphylaxis to COVID‐19 vaccines and enable more people with history of allergy to be vaccinated.