Infective abortive diseases: Q fever

Abstract

In goats, abortions at different stages of gestation are caused by either infectious or noninfectious agents. Major infectious diseases causing abortion in goats include chlamydiosis, toxoplasmosis, leptospirosis, brucellosis, listeriosis, Q fever, and caprine herpes virus infection. Q fever is a ubiquitous zoonotic disease caused by the resistant intracellular bacterium Coxiella burnetii. Coxiella burnetii is increasingly recognized as an important cause of caprine abortion with public health concern. All domestic ruminants are considered as reservoirs of bacteria. Infected animals act as a source of infection for other animals by contaminating the environment with infectious organisms secreted through milk, feces, urine, vaginal mucus, and abortion contents. Inhalation is the main route of infection. Coxiella burnetii abortions are identified in the third trimester of pregnancy. Placental lesions are characterized by a necrotizing placentitis with nonsuppurative inflammation and an associated vasculitis of placental vessels. Many of the chorionic trophoblastic epithelial cells are filled with numerous small coccobacillary organisms, readily identifiable with Giemenez or Wolbach's Giemsa stains or by immunohistochemical procedures. Fetal tissues rarely have lesions and fetuses develop a lymphocytic portal hepatitis, histiocytic bronchopneumonia, and/or lymphocytic interstitial nephritis. The placenta is covered by gray-brown exudate and the intercotyledonary areas are thickened.