Leptospira interrogans associated with hydrallantois in 2 pluriparous Thoroughbred mares

Hydroallantois in a mare associated with schistosomus and unilateral ovarian agenesis in the fetus

Hydropsical conditions in domestic animals are characterized by abnormal fluid accumulation. While their complete pathophysiology remains unclear, factors such as changes in chorioallantoic membranes, placentitis, or fetal abnormalities may contribute. Hydrops present as a medical emergency that can cause complications for the mare. Early diagnosis and treatment are crucial for the mare's prognosis, as fetal survival is often poor. This report describes a case of hydroallantois in a 9-year-old pregnant Quarter mare at 271 days of gestation, leading to dystocia of a non-viable foal with multiple congenital abnormalities. Given the poor prognosis for fetal survival, transcervical gradual fluid drainage and pregnancy termination were performed. The malformed fetus was subsequently delivered and humanely euthanized. Necropsy findings revealed a schistosomus fetus with palatoschisis, a wry nose, prognathism, and unilateral ovarian agenesia. The case underscores the importance of timely intervention in managing hydroallantois. The report contributes to understanding horses' clinical presentation, diagnosis, and management of hydroallantois.

FACTORS AFFECTING SURVIVAL AND FUTURE FOALING RATES IN THOROUGHBRED MARES WITH HYDROPS

Prognosis for life and future fertility in broodmares following hydrops is reportedly good, but evidence to support these reports is limited. The objective of this case series was to describe the prognosis for survival and fertility in mares presented to a referral hospital following diagnosis of hydrops. Medical records were reviewed to identify mares diagnosed with hydrops. Data collected included history (gestation, sire of the foal), clinical findings at presentation and throughout hospitalization (complications, treatments, survival to discharge) and future foaling rates. Thirty mares were presented for hydrops between 2009 to 2019. Ninety percent (27/30) of mares survived (94.7% (18/19) hydrallantois, 75% (6/8) hydramnios) and 95% (20/21) of mares successfully had a future foal, of which 75% (15/21) had a foal the following year. There was no reoccurrence of hydrops. Mares managed with transcervical gradual fluid drainage demonstrated higher survival rate compared to those not managed with transcervical drainage (100% with vs 78.6% without). The most frequent complications observed in mares that did not survive included hypovolemic shock (n=7), hemorrhage (n=4) and laminitis (n=3). Complications observed in mares not returning to breeding included hypovolemic shock and hemorrhage. Causes of non-survival included peritonitis secondary to abdominal wall rupture or uterine tear, and tibial fracture. These results suggest that prognosis for survival and future fertility following a diagnosis of hydrops is good, provided the hydrops is diagnosed and treated appropriately with no damage to the reproductive tract or abdominal wall.

Infectious Uveitis in Horses and New Insights in Its Leptospiral Biofilm-Related Pathogenesis

Uveitis is a sight-threatening eye disease in equids known worldwide that leads to considerable pain and suffering. By far the most common type of uveitis in Germany and neighboring countries is classical equine recurrent uveitis (ERU), which is caused by chronic intraocular leptospiral infection and is the main cause of infectious uveitis in horses. Other infectious causes are extremely rare and are usually clinically distinguishable from ERU. ERU can be treated very effectively by vitreous cavity lavage (vitrectomy). For proper indications of this demanding surgery, it is necessary to differentiate ERU from other types of uveitis in which vitrectomy is not helpful. This can be conducted on the basis of anamnesis in combination with ophthalmologic findings and by aqueous humor examination. During vitrectomy, vitreous material is obtained. These vitreous samples have historically been used for numerous etiologic studies. In this way, a chronic intraocular leptospiral infection has been shown to be the cause of typical ERU and, among other findings, ERU has also been recognized as a biofilm infection, providing new insights into the pathogenesis of ERU and explaining some thus far unexplainable phenomena of ERU. ERU may not only have transmissible aspects to some types of uveitis in humans but may also serve as a model for a spontaneously occurring biofilm infection. Vitreous material obtained during therapeutically indicated vitrectomy can be used for further studies on in vivo biofilm formation, biofilm composition and possible therapeutic approaches.

Managing Reproduction Emergencies in the Field: Part 1: Injuries in Stallions; Injury of the External Portion of the Reproductive Tract and Gestational Conditions in the Mare

Selected emergency conditions of male and female reproductive tracts in horses are described, including injuries affecting the external genitalia of male horses and emergent conditions arising during gestation in mares. Conditions affecting male horses are discussed in the context of breeding stallions, but kicks or other mechanisms of trauma in the groin can also affect geldings. Priapism, paraphimosis, trauma to the scrotum and testicles, and penile injury are discussed. In mares, traumatic vestibular injury, placentitis, hydropsic conditions, prepubic tendon and abdominal wall compromise, and uterine torsion are included. Clinical recognition of the problem, diagnostic procedures, and treatments are summarized.

Causes of equine perinatal mortality

The peripartum period is critical in equine medicine for maintaining healthy mares, and ensuring the delivery of healthy neonatal foals. The field of perinatal mortality in horses is continuously evolving, with several advances being recently made in causes of perinatal fetal and foal loss. This review details the main causes of perinatal loss in horses, through late pregnancy, parturition and the neonatal period. Recent advances in identification of infectious organisms and indicators of survival in neonatal foals will be discussed. Continued advances in reproductive and neonatal medicine will aid improved survival of foals through fewer pregnancy losses, and improved management of high-risk pregnancies and critically ill neonatal foals.

Leptospirosis: An important infectious disease in North American horses

North American horses are commonly exposed to Leptospira organisms. Leptospira Bratislava is the most common infecting serovar but this serovar has not been confirmed to cause clinical disease in North American horses. Leptospira Pomona type kennewicki is responsible for most of the clinical diseases (leptospirosis) in North American horses. Leptospirosis is most commonly associated with diseases of the placenta and fetus, the kidneys and the eyes in horses. In-utero infections in pregnant mares may result in abortion, neonatal illness or birth of an antibody positive healthy foal. Acute renal failure in younger horses and recurrent uveitis in adult horses are other well documented clinical syndromes of leptospirosis. Abortions, neonatal disease and acute renal failure are caused by a subacute infection, while horses with Leptospira associated recurrent uveitis develop ocular disease months or years after the initial Leptospira infection. Diagnosis of Leptospirosis is made by a combination of antigen or antibody testing methods. Mares that abort following Leptospira infection have no additional clinical signs at the time of abortion but may shed the offending Leptospira spp. in the urine for several weeks. Antibiotic treatments are sometimes used in hopes of decreasing Leptospira shedding in infected horses or prophylactically in exposed pregnant mares but documentation of efficacy is lacking. Horses with Leptospira - associated acute renal failure can be successfully treated with antibiotics and supportive care. Recurrent uveitis is commonly associated with leptospirosis in North American horses and although horses may have chronic intraocular infection triggering an immune disease, systemic antimicrobial therapy has not been effective in eliminating the organism from the eye. An equine approved Leptospira Pomona type kennewicki vaccine is now available in North America.

Treatment of Hydropsical Conditions Using Transcervical Gradual Fetal Fluid Drainage in Mares With or Without Concurrent Abdominal Wall Disease

Hydropsical conditions are exceedingly rare in the horse. However, when they occur, they are true emergencies due to the severe enlargement of the pregnant uterus, which can result in clinical signs, such as an enlarged round abdomen, dyspnea, reluctance to walk, and colic, and may lead to the development of abdominal wall disease. The pathogenesis of hydropsical conditions is not fully elucidated, but they have been associated with placentitis and fetal abnormalities. This report describes six cases of hydropsical conditions in mares with or without concurrent abdominal wall disease. Five out of six cases were hydrallantois, and of these five, two mares had abdominal wall disease; the remaining one out of six cases was hydramnios. All mares were treated by termination of the pregnancy through gradual fluid drainage transcervically over a number of hours, and their fetuses were delivered vaginally. All fetuses were euthanized immediately after vaginal delivery. Of the six mares, two had signs of placentitis, two were confirmed seropositive for leptospirosis, and two were euthanized (one because of a vaginal tear that communicated through the peritoneum and one mare that developed abdominal wall rupture and laminitis). The remaining 4 mares were available for follow-up; three mares were not rebred, and one mare became an embryo donor, with a successful embryo recovery. We reported the prevalence of leptospira involvement in two out of six cases of hydrallantois and also described the clinical outcome of the mares after treatment with slow fetal fluid drainage.

The role of leptospirosis in reproductive disorders in horses

Leptospirosis is a zoonotic disease of global importance and has a worldwide distribution. This infection displays clear seasonal nature in some regions of the tropics, where the rainy season is marked by high temperatures. Household and wild animals carry leptospires and contribute to their dissemination in nature. Transmission mainly occurs by contact with water contaminated with the urine of infected animals, and consequently, it is quite widespread especially in times of rain, since many areas are subject to flooding and have poor sanitation. Serological tests demonstrate that Leptospira sp. infection in horses occurs worldwide and that the predominant serovar may vary depending on the region or infection sources. Besides systemic and ocular manifestations, leptospirosis in horses has been recognized as an important disease of the reproductive system, since it leads to the birth of weak foals, stillbirths or neonatal mortality, and mainly to abortion, usually after the sixth month of pregnancy. In this context, this review aims to gather and discuss information about the role of leptospirosis in reproductive disorders in horses.