Role of Position 627 of PB2 and the Multibasic Cleavage Site of the Hemagglutinin in the Virulence of H5N1 Avian Influenza Virus in Chickens and Ducks

Highly pathogenic H5N1 avian influenza viruses have caused major disease outbreaks in domestic and free-living birds with transmission to humans resulting in 59% mortality amongst 564 cases. The mutation of the amino acid at position 627 of the viral polymerase basic-2 protein (PB2) from glutamic acid (E) in avian isolates to lysine (K) in human isolates is frequently found, but it is not known if this change affects the fitness and pathogenicity of the virus in birds. We show here that horizontal transmission of A/Vietnam/1203/2004 H5N1 (VN/1203) virus in chickens and ducks was not affected by the change of K to E at PB2-627. All chickens died between 21 to 48 hours post infection (pi), while 70% of the ducks survived infection. Virus replication was detected in chickens within 12 hours pi and reached peak titers in spleen, lung and brain between 18 to 24 hours for both viruses. Viral antigen in chickens was predominantly in the endothelium, while in ducks it was present in multiple cell types, including neurons, myocardium, skeletal muscle and connective tissues. Virus replicated to a high titer in chicken thrombocytes and caused upregulation of TLR3 and several cell adhesion molecules, which may explain the rapid virus dissemination and location of viral antigen in endothelium. Virus replication in ducks reached peak values between 2 and 4 days pi in spleen, lung and brain tissues and in contrast to infection in chickens, thrombocytes were not involved. In addition, infection of chickens with low pathogenic VN/1203 caused neuropathology, with E at position PB2-627 causing significantly higher infection rates than K, indicating that it enhances virulence in chickens

Is parental consanguinity associated with reduced ovarian reserve?

This observational study assessed whether women descending from consanguineous unions have reduced ovarian reserve compared with daughters of non-consanguine couples. Two hundred and ninety-one women (≤39 years) were treated in a tertiary care centre in Kuwait. Women underwent a complete anamnesis, including an evaluation of the possible presence of parental consanguinity, transvaginal ultrasound on day 2/3 of the cycle to obtain the antral follicle count (AFC), determination of serum concentrations of FSH, LH, oestradiol and in case of low ovarian reserve (AFC < 9) anti-Müllerian hormone (AMH). The median AFC of non-consanguineous daughters was 11, while daughters from consanguineous parents displayed a significantly lower median AFC (7; P < 0⋅0001). FSH was slightly higher in the consanguineous patients, while LH and oestradiol concentrations did not vary between groups. In total, 29.9% of consanguineous patients had an AFC ≥ 9, compared with 63.9% of non-consanguineous patients. Consanguineous patients did not exhibit an age-dependent AFC-decline and displayed reduced AFC and AMH concentrations. The multivariate analysis revealed female consanguinity, as well as surgical history in non-consanguineous women, as strong positive predictors of low ovarian reserve. Parental consanguinity is strongly associated with reduced ovarian reserve. Future studies should evaluate a possible association between parental consanguinity and infertility