Review of Diagnostic Procedures and Approaches to Infectious Causes of Reproductive Failures of Cattle in Australia and New Zealand

Bluetongue (BT) is an insect-transmitted viral disease of wild and domestic ruminants and, occasionally, other species. Amongst domestic livestock, BT is most common in certain breeds of sheep whereas asymptomatic BT virus (BTV) infection of cattle is typical in enzootic regions. BT in cattle can be a feature of specific outbreaks, notably the current epizootic in Europe caused by BTV serotype 8. BTV replicates within mononuclear phagocytic and endothelial cells, lymphocytes and possibly other cell types in lymphoid tissues, the lungs, skin and other tissues. Infected ruminants may exhibit a prolonged but not persistent viraemia and BTV is associated with erythrocytes during the late stages of this prolonged viraemia. The pathogenesis of BT involves injury to small blood vessels in target tissues, but the relative contributions of direct virus-induced cytolysis and virus-induced vasoactive mediators in causing endothelial injury and dysfunction are presently unclear. The lesions of BT are characteristic and include: haemorrhage and ulcers in the oral cavity and upper gastrointestinal tract; necrosis of skeletal and cardiac muscle; coronitis; subintimal haemorrhage in the pulmonary artery; oedema of the lungs, ventral subcutis, and fascia of the muscles of the neck and abdominal wall; and pericardial, pleural and abdominal effusions. Transplacental transmission of BTV in ruminants, with subsequent fetal infection, is a property of specific virus strains, especially those propagated in embryonated eggs or cell culture. The outcome of BTV infection of fetal ruminants is age-dependent, with distinctive cavitating lesions of the central nervous system in animals that survive infection in early gestation. Immune competence to BTV arises by mid-gestation, and animals infected in late gestation can be born viraemic and without significant brain malformations.

Purpose The increased risk of morbidity and mortality from certain microbial infections and the demonstrated improvements in the clinical course of some autoimmune diseases support the existence of pregnancy-related alterations in immune status. Elucidating the changes in innate and adaptive immunity during gestation may improve pregnancy outcomes and facilitate the development of targeted therapies for autoimmune diseases. Method The Viral Immunity and Pregnancy (VIP) study evaluated over 50 subjects longitudinally at three time points during pregnancy and at two time points post-delivery. Leukocyte enumeration was performed; functional responses of NK cells and CD4 T cells were analyzed, and soluble factors such as cytokines, defensins, and steroid hormones were measured in maternal blood. Results In comparison to the post-partum period, the latter part of pregnancy was characterized by significant increases in blood phagocytes and pDCs and decreases in the number and activity of NK and T cells. Alterations were found in antimicrobial proteins and serum cytokines. Conclusions These data show that pregnancy is not a period of immunosuppression but an alteration in immune priorities characterized by a strengthening of innate immune barriers and a concomitant reduction in adaptive/inflammatory immunity in the later stages of pregnancy.

We describe the Q fever epidemic in the Netherlands with emphasis on the epidemiological characteristics of acute Q fever patients and the association with veterinary factors. Data from 3264 notifications for acute Q fever in the period from 2007 through 2009 were analysed. The patients most affected were men, smokers and persons aged 40–60 years. Pneumonia was the most common clinical presentation (62% in 2007 and 2008). Only 3.2% of the patients were working in the agriculture sector and 0.5% in the meat-processing industry including abattoirs. Dairy goat farms with Coxiella burnetii-induced abortion waves were mainly located in the same area where human cases occurred. Airborne transmission of contaminated dust particles from commercial dairy goat farms in densely populated areas has probably caused this epidemic. In 2010, there was a sharp decline in the number of notified cases following the implementation of control measures on dairy goat and sheep farms such as vaccination, hygiene measures and culling of pregnant animals on infected farms. In combination with a rise in the human population with antibodies against C. burnetii, these have most likely ended the outbreak. Development of chronic Q fever in infected patients remains an important problem for years to come.