Chlamydia pecorum-Associated Sporadic Ovine Abortion.

Despite previous detection of Chlamydia pecorum in sporadic ovine abortions, published descriptions of naturally occurring infections with fetoplacental lesions are lacking. This report provides the first descriptions of severe necrosuppurative chorionitis with vasculitis, and fetal pyelonephritis and enteritis in late-term abortions of maiden ewes. Chlamydial infection was detected using a Chlamydia genus-specific qPCR (quantitative polymerase chain reaction) on tissue extracts from 3 fetuses. C. pecorum was identified using a targeted qPCR assay, which also determined infectious load within fetal tissues. The presence of viable C. pecorum in fetal samples was confirmed by cell culture. Multilocus sequence typing (MLST) data indicated that the C. pecorum strains from each fetus were identical and of sequence type (ST) 23. Chlamydia sp. immunohistochemistry showed strong positive immunolabeling of fetoplacental lesions. Other infectious abortigenic agents were excluded with specific testing. This report confirms C. pecorum as a likely cause of ovine abortion and provides the first descriptions of associated fetoplacental lesions in naturally infected sheep.

Prolonged Detection of Bovine Viral Diarrhoea Virus Infection in the Semen of Bulls.

Infection of bulls with bovine viral diarrhoea virus (BVDV) can result in the development of virus persistence, confined to the reproductive tract. These bulls develop a normal immune response with high neutralizing antibody titres. However, BVDV can be excreted in the semen for a prolonged period. Although relatively rare, in this study we describe six separate cases in bulls being prepared for admission to artificial breeding centres. Semen samples were tested in a pan-Pestivirus-reactive real-time PCR assay and viral RNA was detected in semen from five of the bulls for three to eight months after infection. In one bull, virus was detected at low levels for more than five years. This bull was found to have one small testis. When slaughtered, virus was only detected in the abnormal testis. The low levels of BVDV in the semen of these bulls were only intermittently detected by virus isolation in cell culture. This virus-contaminated semen presents a biosecurity risk and confirms the need to screen all batches of semen from bulls that have been previously infected with BVDV. The use of real-time PCR is recommended as the preferred laboratory assay for this purpose.

Identification of a novel nidovirus as a potential cause of large scale mortalities in the endangered Bellinger River snapping turtle (Myuchelys georgesi).

In mid-February 2015, a large number of deaths were observed in the sole extant population of an endangered species of freshwater snapping turtle, Myuchelys georgesi, in a coastal river in New South Wales, Australia. Mortalities continued for approximately 7 weeks and affected mostly adult animals. More than 400 dead or dying animals were observed and population surveys conducted after the outbreak had ceased indicated that only a very small proportion of the population had survived, severely threatening the viability of the wild population. At necropsy, animals were in poor body condition, had bilateral swollen eyelids and some animals had tan foci on the skin of the ventral thighs. Histological examination revealed peri-orbital, splenic and nephric inflammation and necrosis. A virus was isolated in cell culture from a range of tissues. Nucleic acid sequencing of the virus isolate has identified the entire genome and indicates that this is a novel nidovirus that has a low level of nucleotide similarity to recognised nidoviruses. Its closest relatives are nidoviruses that have recently been described in pythons and lizards, usually in association with respiratory disease. In contrast, in the affected turtles, the most significant pathological changes were in the kidneys. Real time PCR assays developed to detect this virus demonstrated very high virus loads in affected tissues. In situ hybridisation studies confirmed the presence of viral nucleic acid in tissues in association with pathological changes. Collectively these data suggest that this virus is the likely cause of the mortalities that now threaten the survival of this species. Bellinger River Virus is the name proposed for this new virus.

The identification of Theileria bicornis in captive rhinoceros in Australia.

Poaching of both black (Diceros bicornis) and white (Ceratotherium simum) rhinoceros in Africa has increased significantly in recent years. In an effort to ensure the survival of these critically endangered species, breeding programs were established in the 1990s in Australia, where a similar climate and habitat is available. In this study we examined blood samples from two C. simum, including a 16 yr old female (Aluka) who died in captivity, and a 17 yr old asymptomatic male (Umfana). Bloods from seven healthy D. bicornis housed at the zoo were also collected. All samples were tested for the presence of piroplasms via blood smear and PCR. A generic PCR for the 18S rRNA gene of the Piroplasmida revealed the presence of piroplasm infection in both dead and asymptomatic C. simum. Subsequent sequencing of these amplicons revealed the presence of Theileria bicornis. Blood smear indicated that this organism was present at low abundance in both affected and asymptomatic individuals and was not linked to the C. simum mortality. T. bicornis was also detected in the D. bicornis population (n = 7) housed at Taronga Western Plains Zoo using PCR and blood film examination; however only animals imported from Africa (n = 1) tested T. bicornis positive, while captive-born animals bred within Australia (n = 6) tested negative suggesting that transmission within the herd was unlikely. Phylogenetic analysis of the full length T. bicornis 18S rRNA genes classified this organism outside the clade of the transforming and non-transforming Theileria with a new haplotype, H4, identified from D. bicornis. This study revealed the presence of Theileria bicornis in Australian captive populations of both C. simum and D. bicornis and a new haplotype of the parasite was identified.