Transplacental transmission in cattle: is Toxoplasma gondii less potent than Neospora caninum?

We compared the transplacental-transmission ability of Toxoplasma gondii and Neospora caninum in cattle. One uninfected pregnant heifer served as control, while three were inoculated with N. caninum K9WA strain and four with T. gondii RH strain at their midgestational period. Both infected groups showed clinical signs and antibodies either to N. caninum or T. gondii, while the control animal was normal. Two (50%) Toxoplasma dams aborted on days 6 and 11 postinoculation. T. gondii tachyzoites were found in various organs of those dams that had abortions but not in their fetuses. Two Neospora dams did not abort but gave birth to subclinically infected calves. The remaining two Toxoplasma dams and one from Neospora group became recumbent. Those two dams and their fetuses showed disseminated Toxoplasma DNA, but no Neospora DNA was found. Our findings suggest that maternal toxoplasmosis could be a cause of abortion and congenital toxoplasmosis in cattle, especially when they are infected by virulent strains.

Genetic analysis of beak and feather disease virus isolated from captive psittacine birds in Thailand.

Beak and feather disease virus (BFDV) is a causative agent of psittacine beak and feather disease. Genome sequences of BFDVs isolated from Thailand have not hitherto been reported. The whole genomes of 17 BFDV isolates, obtained from 12 psittacine genera, were amplified and subjected to direct sequencing revealing a length ranging from 1,990 to 2,015 nucleotides. The predicted open reading frames (ORFs) in the viral genome varied from four to six. Only ORF1, ORF2, and ORF5 were found in all isolates. Deduced amino acid sequences of BFDV ORF2 were used to construct a phylogenetic tree. The phylogram grouped BFDV into ten clusters, which showed either host species relationship or regional restriction. The Thai isolates, were grouped into three clusters, cluster I, II, and V. Cluster I and II showed restricted geographical region to Thailand, and cluster II also showed a close relationship with BFDV isolated from Australia. Cluster V demonstrated neither restricted region nor species specificity of birds. In this cluster, there was an insertion of 16 nucleotides at non coding region of all BFDV isolates. The genetic information obtained from this study can be used to help understand BFDV diversity and evolution in Thailand.