Anaemia in Lambs Caused by Mycoplasma ovis: Global and Australian Perspectives

Abstract

Mycoplasma ovis (formerly Eperythrozoon ovis) is a haemotropic parasitic bacterium found within erythrocytes and distributed widely in global sheep and goat production regions. M. ovis is transmitted by biting flies and by contaminated instruments, causing morbidity and mortalities from anaemia, usually within 6 weeks following blood-exposure procedures, particularly vaccination, castration, ear tagging, mulesing, and occasionally crutching and shearing. Affected animals develop haemolytic anaemia and may have jaundice, causing abattoir condemnations. The typical history, clinical and pathological findings, display of M. ovis in blood smears and/or by PCR is diagnostic, although immune responses deplete M. ovis from smears; hence, in-contact healthy animals should be examined. Differential diagnoses include haemonchosis, fasciolosis, malnutrition (copper or vitamin B12 deficiency), and plant toxicities. M. ovis parasitaemia may persist, with recrudescence following stressful events, although most older sheep remain immune. Human infections have been reported. Inadequate socioeconomic data present difficulties in assessing the impact of M. ovis on production and as antimicrobial therapy is ineffective, its control requires management practices that minimize the impact of invasive procedures in periods when risks of M. ovis transmission are more likely. Although considered an emerging pathogen, recent improvements in welfare attitudes and husbandry practices on Australian sheep farms may potentially limit the transmission of M. ovis.

Role of Topical Anaesthesia in Pain Management of Farm Animals, a Changing Paradigm

“…Mycoplasma ovis ( M. ovis, formerly E. ovis) causes anaemia in lambs and is considered a pathogen of emerging concern, although in the Australian sheep industry, there are few reports in recent years and anecdotal observations suggest the occurrence of M. ovis outbreaks may possibly be declining [ 45 ]. Speculation is that this may reflect a range of factors, including a decrease in the population of Merino sheep as a proportion of the national sheep flock in recent decades, with fewer sheep requiring the mulesing operation to provide lifetime protection against myiasis, a risk factor for transmission of M. ovis if conducted when insects are prevalent.…”

“…Speculation is that this may reflect a range of factors, including a decrease in the population of Merino sheep as a proportion of the national sheep flock in recent decades, with fewer sheep requiring the mulesing operation to provide lifetime protection against myiasis, a risk factor for transmission of M. ovis if conducted when insects are prevalent. However, the potential decline in M. ovis outbreaks may also reflect improvements in hygiene and animal welfare practices during lamb marking on many sheep production enterprises in Australia [ 45 ]. Mandatory accreditation for those performing the mulesing operation, increasing use of professional contractors, declining use of blood-soaked surgical equipment, increased use of antisepsis and more appropriate administration of blowfly control products may all be of relevance to this anecdotal observation.…”

“…It was also suggested that since pain welfare research commenced in 2005, the Australian sheep industry has experienced increasing uptake of the TAF for lamb marking and mulesing, with over 120 million lambs now treated. The low pH of ~2.8 and antisepsis in the TAF provides antibacterial activity that may also have contributed to reduced M. ovis transmission at marking, mulesing and shearing [ 45 ], although further work is required to investigate this hypothesis.…”

Characterization of Lung Microbiomes in Pneumonic Hu Sheep Using Culture Technique and 16S rRNA Gene Sequencing

“…Notably, resistance to tylosin and tetracycline has been observed in a subset of individuals [5]. Mycoplasma ovipneumoniae (M. ovipneumoniae), originally identified within a sheep flock situated in Queensland, Australia in the year 1972 [6], is now widely recognized as a respiratory pathogen that affects both domestic and wild sheep, as well as goats, worldwide [7][8][9]. Moreover, Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae) have also emerged as pathogenic bacteria associated with pneumonia in sheep [10].…”

“…Hu sheep, a renowned sheep breed in China, stands out for its remarkable characteristics of early maturation and exceptional productivity [13]. There have been a growing number of reported cases of sheep pneumonia in China in recent years [9,14]. Moreover, numerous studies have endeavored to characterize the variability of lung microbiotas in healthy sheep [15,16].…”