The Outcome of Porcine Foetal Infection with Bungowannah Virus Is Dependent on the Stage of Gestation at Which Infection Occurs. Part 2: Clinical Signs and Gross Pathology

Bungowannah virus is a novel pestivirus identified from a disease outbreak in a piggery in Australia in June 2003. The aim of this study was to determine whether infection of pregnant pigs with Bungowannah virus induces the clinical signs and gross pathology observed during the initial outbreak and how this correlates with the time of infection. Twenty-four pregnant pigs were infected at one of four stages of gestation (approximately 35, 55, 75 or 90 days). The number of progeny born alive, stillborn or mummified, and signs of disease were recorded. Some surviving piglets were euthanased at weaning and others at ages up to 11 months. All piglets were subjected to a detailed necropsy. The greatest effects were observed following infection at 35 or 90 days of gestation. Infection at 35 days resulted in a significant reduction in the number of pigs born alive and an increased number of mummified foetuses (18%) and preweaning mortalities (70%). Preweaning losses were higher following infection at 90 days of gestation (29%) and were associated with sudden death and cardiorespiratory signs. Stunting occurred in chronically and persistently infected animals. This study reproduced the clinical signs and gross pathology of the porcine myocarditis syndrome and characterised the association between the time of infection and the clinical outcome.

The Outcome of Porcine Foetal Infection with Bungowannah Virus Is Dependent on the Stage of Gestation at Which Infection Occurs. Part 1: Serology and Virology

Bungowannah virus is a novel porcine pestivirus identified in a disease outbreak in Australia in 2003. The aim of this study was to determine the outcome of infection of the pregnant pig with this virus. Twenty-four pregnant pigs were infected at days 35, 55, 75 or 90 of gestation. Blood, tonsillar and rectal swabs were collected from each pig at birth and then weekly until euthanasia or death. Tissues were sampled at necropsy. Viral load was measured by real-time reverse-transcription polymerase chain reaction (qRT-PCR) and antibody levels in serum by peroxidase-linked immunoassay. Bungowannah virus was detected in the serum and excretions of all infected pigs at birth regardless of the stage of gestation at which infection occurred. Persistent infections occurred following infection prior to the development of foetal immunocompetence. Unexpectedly some animals infected at day 55 of gestation later cleared the virus and seroconverted. Viraemia and viral shedding resolved quickest following infection in late gestation.

A comparative study of 25µg versus 50µg vaginal misoprostol for induction of labour at term premature rupture of membrane

Background: At term, infection remains the most serious complication associated with PROM for the mother and the neonate Induction of labour significantly reduces the risk of maternal and foetal infection. This randomized comparative study has been done to compare the effectiveness and safety of low and high dosage (25 mcg and 50mcg) regimen of vaginal misoprostol for induction in term PROM patients.Methods: At term, infection remains the most serious complication associated with PROM for the mother and the neonate Induction of labour significantly reduces the risk of maternal and foetal infection. This randomized comparative study has been done to compare the effectiveness and safety of low and high dosage (25 mcg and 50mcg) regimen of vaginal misoprostol for induction in term PROM patients.Results: PROM to delivery interval was significantly shorter with 50mcg vaginal misoprostol as compared to 25 mcg vaginal misoprostol (15.71±3.29 hours vs. 18.23±3.23 hours, (p value = 0.0023) Number of doses required was less with 50mcg vaginal misoprostol group as compared to 25mcg vaginal misoprostol (1.22±0.42 vs. 1.91±0.80, p value <0.05). 83.6% women in group A and 69.09% women in group B underwent spontaneous vaginal delivery within 24 hours. 3.64% women in group A and 7.27% in group B had instrumental delivery. Caesarean section was performed in 12.27% cases in group A and 23.64% cases in group B. The complication rate was comparable.Conclusions: 50mcg vaginal misoprostol is more effective and safe for induction of labour at term PROM as compared to 25 mcg vaginal misoprostol

Evidence that primary infection of Charollais sheep withToxoplasma gondiimay not prevent foetal infection and abortion in subsequent lambings

SUMMARYA study carried out on a sheep farm examined whetherToxoplasma gondiifoetal infection and associated abortion occur in successive lambings. We identified 29 ewes that gave birth to lambs on at least 2 successive years over our study period, 2000–2003. Tissue samples from the progeny of these ewes were analysed by PCR to determine infection status withT. gondii.T. gondii-infected lambs were born in 31% of successive pregnancies.T. gondii-positive lambs were aborted in successive pregnancies in 21% of lambings during study period, 2000–2003. The frequency of successive abortions within this flock over the period 1992–2003 was 18%. If a lamb was congenitally infected there was a high risk (69%) that the successive lamb from that ewe would also be congenitally infected. Similarly, if a lamb was aborted there was a high risk (55%) of abortion in the next lamb produced. These data suggest that life-long immunity toT. gondiiinfections may not always be acquired following an initial infection and raises the question as to whether the mechanisms ofT. gondiitransmission prior to and during ovine pregnancies are fully understood.

Diagnosis of bovine neosporosis: Recent advances and perspectives

Neospora caninum is considered a major cause of abortion in cattle. Appropriate techniques for diagnosis of bovine neosporosis, both in vivo and in aborted foetuses, have been developed in the last ten years and some of them are commercially available. For diagnosis in live animals, detection of antibodies in serum or milk has been shown to be the best option both at the herd and the individual level. These techniques are excellent tools to examine N. caninum-associated abortion problems and to adopt some basic herd-control measures. Concerning foetal diagnosis, detection of compatible lesions by histological examination and parasites by PCR in brain (as well as heart and liver) are the best choices. Diagnostic criteria to distinguish foetal infection and Neospora-associated abortion are based not only on the demonstration of the parasite in the foetus but also on the extent and severity of the lesions in the foetus, foetal age and the assessment of neosporosis at the herd level. In the near future, new tools to diagnose infection should help to detect animals with parasite reactivation by testing the immune response to stage-specific antigens and lead to the development of molecular typing methods to characterise different parasite isolates. Finally, uniform diagnostic procedures need to be established between laboratories and countries in order to standardise result interpretation. The role of National or Regional Reference Laboratories is essential in countries or regions where control programmes for the disease are being developed.