The mare reproductive loss syndrome and the eastern tent caterpillar: a toxicokinetic/statistical analysis with clinical, epidemiologic, and mechanistic implications.
نویسندگان
چکیده
During 2001, central Kentucky experienced acute transient epidemics of early and late fetal losses, pericarditis, and unilateral endophthalmitis, collectively referred to as mare reproductive loss syndrome (MRLS). A toxicokinetic/statistical analysis of experimental and field MRLS data was conducted using accelerated failure time (AFT) analysis of abortions following administration of Eastern tent caterpillars (ETCs; 100 or 50 g/day or 100 g of irradiated caterpillars/day) to late-term pregnant mares. In addition, 2001 late-term fetal loss field data were used in the analysis. Experimental data were fitted by AFT analysis at a high (P <.0001) significance. Times to first abortion ("lag time") and abortion rates were dose dependent. Lag times decreased and abortion rates increased exponentially with dose. Calculated dose x response data curves allow interpretation of abortion data in terms of "intubated ETC equivalents." Analysis suggested that field exposure to ETCs in 2001 in central Kentucky commenced on approximately April 27, was initially equivalent to approximately 5 g of intubated ETCs/day, and increased to approximately 30 g/day at the outbreak peak. This analysis accounts for many aspects of the epidemiology, clinical presentations, and manifestations of MRLS. It allows quantitative interpretation of experimental and field MRLS data and has implications for the basic mechanisms underlying MRLS. The results support suggestions that MRLS is caused by exposure to or ingestion of ETCs. The results also show that high levels of ETC exposure produce intense, focused outbreaks of MRLS, closely linked in time and place to dispersing ETCs, as occurred in central Kentucky in 2001. With less intense exposure, lag time is longer and abortions tend to spread out over time and may occur out of phase with ETC exposure, obscuring both diagnosis of this syndrome and the role of the caterpillars.
منابع مشابه
The Mare Reproductive Loss Syndrome and the Eastern Tent Caterpillar II: A Toxicokinetic/Clinical Evaluation and a Proposed Pathogenesis: Septic Penetrating Setae
Reviewing the mare reproductive loss syndrome (MRLS), it is proposed that the fundamental mechanism of this syndrome, which includes early fetal loss, late fetal loss, uveitis, pericarditis, and encephalitis, is tissue penetration by septic barbed setal fragments (septic penetrating setae) from Eastern tent caterpillars (Malacosoma americanum). Once ingested, these barbed setal fragments migrat...
متن کاملThe Mare Reproductive Loss Syndrome (MRLS) and the Eastern Tent Caterpillar: Immunological Testing of Aborting Mares
Mare reproductive loss syndrome (MRLS) describes a condition of equine early-term and late-term fetal losses in which the etiology has not been fully characterized. Involvement of Eastern tent caterpillars (ETC) has been highly considered because oral administration of ETC rapidly induces abortion in pregnant mares. Pathologic lesions observed in placental and fetal tissues of horses with chara...
متن کاملCase-control study of factors associated with excessive proportions of early fetal losses associated with mare reproductive loss syndrome in central Kentucky during 2001.
OBJECTIVE To identify factors associated with excessive proportions of early fetal losses associated with mare reproductive loss syndrome in central Kentucky during 2001. DESIGN Case-control study. PROCEDURE Questionnaires were used to collect information on farm-, pasture-, and individual animal-level factors purportedly associated with mare reproductive loss syndrome. Data were collected ...
متن کاملInvited review: the role of caterpillars in mare reproductive loss syndrome: a model for environmental causes of abortion.
A new abortigenic disease, now known as mare reproductive loss syndrome (MRLS), significantly affected the horse industry in the Ohio River Valley of the United States in late April and early May of 2001 and 2002. In 2001, approximately 25% of all pregnant mares aborted within several weeks (over 3,000 mares lost pregnancies), and abortion rates exceeded 60% on some farms. Mare reproductive los...
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ورودعنوان ژورنال:
- Veterinary therapeutics : research in applied veterinary medicine
دوره 4 4 شماره
صفحات -
تاریخ انتشار 2003