Clinical findings and treatment of listeriosis in 67 sheep and goats

Risk factors associated with outcome in goats with encephalitic listeriosis: A retrospective study of 36 cases from 2008 to 2021

BACKGROUND

There exists a scarcity of information on risk factors associated with case outcomes in goats diagnosed with encephalitic listeriosis.

OBJECTIVE

Evaluate risk factors associated with outcomes in 36 cases of suspected encephalitic listeriosis in goats presented to a referral hospital.

ANIMALS

Thirty-six goats (26 does, 7 bucks, and 3 wethers) were presented to Auburn University Large Animal Teaching Hospital between 2008 and 2021 for treatment of neurologic disease diagnosed as encephalitic listeriosis based on any combination of clinical signs, cerebral spinal fluid (CSF) analysis, or postmortem examination.

METHODS

Retrospective study. Data were analyzed as binary and under a proportional odds model. The medical records were searched for presumptive encephalitic listeriosis in goats between 2008 and 2021. Data collected included signalment (sex, age, and breed), history, clinical signs, temperature, and ability to stand at presentation. Final diagnosis, CSF results, all treatments, outcomes, and results of necropsy were also collected for analysis.

RESULTS

Male goats were 14 (95% CI: 1.98-166.0) times more likely to be a non-survivor compared to females despite being presented with similar history, clinical signs, and treatments. Animals presented with circling or a history of circling were 6.24 (95% CI: 1.40-23.21) times more likely to be a survivor than a non-survivor. Other risk factors evaluated were not significantly associated with outcomes.

CONCLUSIONS AND CLINICAL IMPORTANCE

Few risk factors were associated with outcomes. Duration of clinical signs, antimicrobial or anti-inflammatory choices, or CSF results were not associated with outcome. Only sex and history or presence of circling were associated with case outcomes.

High multidrug resistance of Listeria monocytogenes and association with water sources in sheep and goat dairy flocks in Jordan

Listeria monocytogenes is a significant pathogen that causes listeriosis in humans and small ruminants. This study aimed to estimate the prevalence, antimicrobial resistance and risk factors of L. monocytogenes in small dairy ruminants in Jordan. A total of 948 milk samples were collected from 155 sheep and goat flocks across Jordan. L. monocytogenes was isolated from the samples, confirmed and tested for 13 clinically important antimicrobials. Data were also collected on the husbandry practices to identify risk factors for the presence of L. monocytogenes. The results showed that the flock-level prevalence of L. monocytogenes was 20.0% (95% CI; 14.46%-26.99%) and the prevalence in the individual milk samples was 6.43% (95% CI; 4.92%-8.36%). The univariable (UOR=2.65, p = 0.021) and multivariable (AOR=2.49, p = 0.028) analyses showed that using water from municipality pipelines as a water source in the flock reduced L. monocytogenes prevalence. All L. monocytogenes isolates were resistant to at least one antimicrobial. High percentages of the isolates were resistant to ampicillin (83.6%), streptomycin (79.3%), kanamycin (75.0%), quinupristin/dalfopristin (63.8%) and clindamycin (61.2%). About 83.6% of the isolates (94.2% and 75% of the sheep and goat isolates) exhibited multidrug resistance (resistance to ≥3 antimicrobial classes). In addition, the isolates exhibited fifty unique antimicrobial resistance profiles. Thus, it's recommended to restrict the misuse of clinically important antimicrobials and to chlorinate and monitor the water sources in sheep and goat flocks.

Molecular characterization and hematological analysis of Listeria monocytogenes infection in dairy cows in Punjab (Pakistan)

Listeriosis is an emerging bacterial disease of animals and humans worldwide, caused by Listeria monocytogenes. The infected dairy cows continuously shed the microbes in their milk, a human being's concern. This study was designed to molecular characterize the Listeria monocytogenes isolated from symptomatic cow's milk of tehsils Samundri, Gujar khan, and Alipur of Punjab. A total of 175 milk samples were collected, pre-enriched and cultured on PALCAM agar. The affirmation of the hlyA gene of Listeria monocytogenes was performed by polymerase chain reaction (PCR) and 3.43% of isolates were found positive. The phylogenetic analysis showed a resemblance of our isolates of Listeria monocytogenes with India (KP965733), the USA (DQ812484), and 3 of our isolates made a clade. The leucocytes and neutrophils count were found significantly increased in listeriosis affected cows. The Chi-square test showed a significant association between poor quality silage feeding and listeriosis. The presence of L.monocytogenes in cow's milk indicates a potential threat to humans. It is further recommended that it should be consistently monitored to ensure food safety.

Listeria monocytogenes at the interface between ruminants and humans: A comparative pathology and pathogenesis review

The bacterium Listeria monocytogenes (Lm) is widely distributed in the environment as a saprophyte, but may turn into a lethal intracellular pathogen upon ingestion. Invasive infections occur in numerous species worldwide, but most commonly in humans and farmed ruminants, and manifest as distinct forms. Of those, neuroinfection is remarkably threatening due to its high mortality. Lm is widely studied not only as a pathogen but also as an essential model for intracellular infections and host-pathogen interactions. Many aspects of its ecology and pathogenesis, however, remain unclear and are rarely addressed in its natural hosts. This review highlights the heterogeneity and adaptability of Lm by summarizing its association with the environment, farm animals, and disease. It also provides current knowledge on key features of the pathology and (molecular) pathogenesis of various listeriosis forms in naturally susceptible species with a special focus on ruminants and on the neuroinvasive form of the disease. Moreover, knowledge gaps on pathomechanisms of listerial infections and relevant unexplored topics in Lm pathogenesis research are highlighted.

Listeriosis in a peri-urban area: Cultural and molecular characterization of Listeria monocytogenes isolated from encephalitic goats

Background and Aim:

Listeriosis in food animals bears a significant threat to human health. Detailed investigations into the cause facilitate proper management of the disease. This study reports the cultural, pathological, and molecular characterization of Listeria monocytogenes isolated from encephalitic goats from peri-urban Guwahati, Assam.

Materials and Methods:

Out of nine suspected samples, five positive isolates of L. monocytogenes were subjected to bacteriological, biochemical, and molecular tests. The genus and species-specific L. monocytogenes 16S rRNA and prs genes were amplified by polymerase chain reaction (PCR) to yield 1200 and 370 bp sized products, respectively. The encephalitic form of the disease was characterized by circling movement, high fever, and terminal recumbence.

Results:

All the five isolates were confirmed to be L. monocytogenes based on PCR amplification of genus and species-specific 16S rRNA and prs gene products. The isolates were sensitive to ciprofloxacin, oxytetracycline (OTC), and norfloxacin, but resistant to doxycycline and erythromycin. A high dose of OTC was used in a goat at the early stage of clinical symptom and the animal recovered clinically.

Conclusion:

Listeriosis in goats could pose a significant public health threat as the meat (occasionally milk) or meat products from goats are widely consumed by the people of Assam. Understanding the molecular epidemiological aspects of L. monocytogenes infections of food animal species should, therefore, be the priority in this part of the country.

The Scrapie Prevalence in a Goat Herd Is Underestimated by Using a Rapid Diagnostic Test

Current European surveillance regulations for scrapie, a naturally occurring transmissible spongiform encephalopathy (TSE) or prion disease in sheep and goats, require testing of fallen stock or healthy slaughter animals, and outline measures in the case of confirmation of disease. An outbreak of classical scrapie in a herd with 2500 goats led to the culling of the whole herd, providing the opportunity to examine a subset of goats, take samples, and examine them for the presence of disease-associated prion protein (PrPSc) to provide further information on scrapie test sensitivity, pathology, and association with prion protein genotype. Goats were examined clinically prior to cull, and the brains examined post mortem by Bio-Rad ELISA, a rapid screening test used for active surveillance in sheep and goats, and two confirmatory tests, Western blot and immunohistochemistry. Furthermore, up to 10 lymphoid tissues were examined by immunohistochemistry. Of 151 goats examined, three (2.0%) tested positive for scrapie by ELISA on brain, confirmed by confirmatory tests, and a further five (3.3%) were negative by ELISA but positive by at least one of the confirmatory tests. Only two of these, both positive by ELISA, displayed evident signs of scrapie. In addition, 10 (6.6%) goats, which also included two clinical suspects, were negative on brain examination but had detectable PrPSc in lymphoid tissue. PrPSc was detected most frequently in the medial retropharyngeal lymph node (LN; 94.4% of all 18 cases) and palatine tonsil (88.9%). Abnormal behavior and circling or loss of balance when blindfolded were the best clinical discriminators for scrapie status. None of the goats that carried a single allele in the prion protein gene associated with increased resistance to scrapie (Q211, K222, S146) were scrapie-positive, and the percentage of goats with these alleles was greater than expected from previous surveys. Significantly more goats that were scrapie-positive were isoleucine homozygous at codon 142 (II142). The results indicate that the sensitivity of the applied screening test is poor in goats compared to the confirmatory tests as gold standard, particularly for asymptomatic animals. Sensitivity of surveillance could be improved by testing retropharyngeal LN or palatine tonsil in addition to brain.

Metabolic profiling of listeria rhombencephalitis in small ruminants by 1 H high-resolution magic angle spinning NMR spectroscopy

Listeria rhombencephalitis is caused by infection with Listeria monocytogenes and is associated with a high mortality rate in humans and ruminants. Little is known about the metabolic changes associated with neurolisteriosis in particular and infectious central nervous system (CNS) diseases in general. The purpose of our study was to investigate the metabolic changes associated with listeria rhombencephalitis in small ruminants (goats and sheep) as a model for inflammatory CNS disease by ¹ H high-resolution magic angle spinning nuclear magnetic resonance (¹ H HR-MAS NMR) spectroscopy of brain biopsies obtained from the brainstem and thalamus. Statistical analysis revealed distinct differences in the metabolic profile of brainstem biopsies, the primary location of listeria rhombencephalitis with moderate or severe inflammatory changes. N-Acetylaspartate (NAA), N-acetylaspartylglutamate, choline, myo-inositol and scyllo-inositol were decreased, and glycine, phosphocholine, taurine and lactate were increased, in the diseased group (n = 13) in comparison with the control group (n = 12). In the thalamus, which showed no or only mild inflammatory changes in the majority of animals, no statistically significant metabolic changes were observed. However, trends for metabolic alterations were partly the same as those found in the brainstem, including NAA, choline and lactate. This may be an indicator of metabolic changes occurring in the early stages of the disease. Therefore, further research with a larger number of animals is needed to evaluate the presence of subtle metabolic changes associated with mild inflammatory changes in the thalamus. In conclusion, ¹ H HR-MAS NMR investigation of listeria rhombencephalitis identified brain metabolite changes, offering new insights into the disease pathophysiology.

The olfactory epithelium as a port of entry in neonatal neurolisteriosis

Bacterial infections of the central nervous system (CNS) remain a major cause of mortality in the neonatal population. Commonly used parenteral infection models, however, do not reflect the early course of the disease leaving this critical step of the pathogenesis largely unexplored. Here, we analyzed nasal exposure of 1-day-old newborn mice to Listeria monocytogenes (Lm). We found that nasal, but not intragastric administration, led to early CNS infection in neonate mice. In particular, upon bacterial invasion of the olfactory epithelium, Lm subsequently spread along the sensory neurons entering the brain tissue at the cribriform plate and causing a significant influx of monocytes and neutrophils. CNS infection required listeriolysin for penetration of the olfactory epithelium and ActA, a mediator of intracellular mobility, for translocation into the brain tissue. Taken together, we propose an alternative port of entry and route of infection for neonatal neurolisteriosis and present a novel infection model to mimic the clinical features of late-onset disease in human neonates.

Listeria monocytogenes causes meningitis in newborns. Here, Pägelow et al. present a mouse model of neonatal cerebral listeriosis, and show that nasal inoculation, but not intragastric administration, leads to early brain infection in the absence of bacteraemia during the neonatal period.

Suppurative infectious diseases of the central nervous system in domestic ruminants

ABSTRACT: This study describes suppurative infectious diseases of the central nervous system (CNS) in domestic ruminants of southern Brazil. Reports from 3.274 cattle, 596 sheep and 391 goats were reviewed, of which 219 cattle, 21 sheep and 7 goats were diagnosed with central nervous system inflammatory diseases. Suppurative infectious diseases of the CNS corresponded to 54 cases (28 cattle, 19 sheep and 7 goats). The conditions observed consisted of listerial meningoencephalitis (8 sheep, 5 goats and 4 cattle), suppurative leptomeningitis and meningoencephalitis (14 cattle, 2 goats and 1 sheep), cerebral (6 cattle and 2 sheep), and spinal cord (7 sheep) abscesses, and basilar empyema (4 cattle and 1 sheep). Bacterial culture identified Listeria monocytogenes (9/54 cases), Escherichia coli (7/54 cases), Trueperella pyogenes (6/54 cases) and Proteus mirabilis (1/54 cases). All cases diagnosed as listeriosis through histopathology yielded positive immunostaining on immunohistochemistry, while 12/17 of the cases of suppurative leptomeningitis and meningoencephalitis presented positive immunostaining for Escherichia coli. Meningoencephalitis by L. monocytogenes was the main neurological disease in sheep and goats, followed by spinal cord abscesses in sheep. In cattle, leptomeningitis and suppurative meningoencephalitis was the most frequent neurological disease for the species, and E. coli was the main cause of these lesions. Basilar empyema, mainly diagnosed in cattle, is related to traumatic injuries, mainly in the nasal cavity, and the main etiologic agent was T. pyogenes.

Brainstem and Cranial Nerve Disorders of Ruminants

Asymmetrical signs of brainstem disease occur relatively infrequently in ruminants. The most common differential diagnoses include listeriosis, otitis media/interna, and pituitary abscess syndrome. Although these conditions produce signs of brainstem dysfunction, the diseases can usually be differentiated based on historical findings and subtle clinical differences. Basic laboratory diagnostic tests are often not specific in the definitive diagnosis but may be supportive. Advanced imaging techniques have proven to be useful in the diagnosis of otitis media/interna. Presumptive clinical diagnosis is confirmed at necropsy. Treatment involves a prolonged course of antibiotic therapy but is unrewarding in cases of pituitary abscess syndrome.

Listeria monocytogenes associated kerato-conjunctivitis in four horses in Norway

Listeria monocytogenes has been reported to cause various infectious diseases in both humans and animals. More rarely, ocular infections have been reported. To our knowledge, only two cases of Listeria keratitis have been described in horses. We report kerato-conjunctivitis in four Norwegian horses associated with L. monocytogenes. Clinically, all cases were presented with recurrent unilateral kerato-conjunctivitis. L. monocytogenes bacteria were isolated from swab samples from all cases, and cytology carried out in 3 cases was indicative of L. monocytogenes infection. The present report describes the first known cases in which L. monocytogenes has been isolated from keratitic lesions in horses in Norway. A potential risk factor may be feeding of silage or haylage, but other sources of infection cannot be ruled out. The phenotypic features including antimicrobial susceptibility and serotype of the isolates are described. Laboratory detection of L. monocytogenes demands extra caution since only low numbers of bacteria were detected in the eye-swabs, probably due to the low volume of sample material and the intracellular niche of the bacterium. A general poor response to treatment in all these cases indicates that clinicians should pay extra attention to intensity and duration of treatment if L. monocytogenes is identified in connection with equine kerato-conjunctivitis.

A retrospective study of brain lesions in goats submitted to three veterinary diagnostic laboratories

A retrospective study of brain lesions in goats was conducted to identify the range of lesions and diseases recognized and to make recommendations regarding the best tissues to examine and tests to conduct in order to maximize the likelihood of making a definitive diagnosis in goats that may have had clinical signs referable to the brain. One hundred thirty-nine goats with a brain lesion were identified. The most common lesion, in 52.5% of the goats, was suppurative inflammation. Approximately two-thirds of these goats had encephalitic listeriosis. Other goats were found to have suppurative inflammation in association with septicemia, pituitary abscesses, dehorning injury, and otitis. Thirty goats (21.6%) were diagnosed with polioencephalomalacia. Twenty-one goats (15.1%) were diagnosed with nonsuppurative inflammation. In more than half of these goats, no definitive diagnosis was made, while 8 were infected with Caprine arthritis encephalitis virus and 1 with Rabies virus. However, few goats were tested for rabies. Based on these findings, it is recommended that, in addition to appropriate handling of the brain, the head should be examined with attention paid to the sella turcica and the temporal bones for evidence of a pituitary abscess and otitis, respectively. Histologic examination should include multiple areas of the brain, including the brainstem, for lesions of encephalic listeriosis; the cerebral cortex, for lesions of polioencephalomalacia; and the hippocampus, for Negri bodies associated with Rabies virus infection. Consideration should be given to collecting samples of other tissues including, but not limited to, the spinal cord and liver for ancillary testing if warranted.

Targeting of the central nervous system by Listeria monocytogenes

Among bacteria that reach the central nervous system (CNS), Listeria monocytogenes (Lm) is one of deadliest, in human and ruminant. This facultative intracellular bacterium has the particularity to induce meningitis, meningoencephalitis and rhombencephalitis. Mechanisms by which Lm accesses the CNS remain poorly understood, but two major routes of infection have been proposed, based on clinical, in vitro and in vivo observations. A retrograde neural route is likely to occur in ruminants upon crossing of the oral epithelium, and this probably accounts for the observation that Lm induces almost exclusively rhombencephalitis in these animals. In contrast, the hematogenous route is likely the most frequent in human, in whom bacteria circulating in the blood, either free or associated with leukocytes are thought to breach the blood-brain barrier. New animal models that faithfully reproduce the hallmarks of human neurolisterisosis will allow addressing the molecular mechanisms underlying Lm ability to induce CNS disease, and improve our understanding of the pathophysiology of this deadly infection.

FSL J1-208, a virulent uncommon phylogenetic lineage IV Listeria monocytogenes strain with a small chromosome size and a putative virulence plasmid carrying internalin-like genes

The bacterial genus Listeria contains both saprotrophic and facultative pathogenic species. A small genome size has been suggested to be associated with the loss of pathogenic potential of L. welshimeri and L. seeligeri. In this paper we present data on the genome of L. monocytogenes strain FSL J1-208, a representative of phylogenetic lineage IV. Although this strain was isolated from a clinical case in a caprine host and has no decreased invasiveness in human intestinal epithelial cells, our analyses show that this strain has one of the smallest Listeria chromosomes reported to date (2.78 Mb). The chromosome contains 2,772 protein-coding genes, including well-characterized virulence-associated genes, such as inlA, inlB, and inlC and the full prfA gene cluster. The small genome size is mainly caused by the absence of prophages in the genome of L. monocytogenes FSL J1-208, and further analyses showed that the total size of prophage-related regions is highly correlated to chromosome size in the genus Listeria. L. monocytogenes FSL J1-208 carries a unique type of plasmid of approximately 80 kbp that does not carry genes annotated as being involved in resistance to antibiotics or heavy metals. The accessory genes in this plasmid belong to the internalin family, a family of virulence-associated proteins, and therefore this is the first report of a potential virulence plasmid in the genus Listeria.

Examination techniques and therapeutic regimens for the ruminant and camelid eye

A step-wise procedure and necessary equipment for examination of the ruminant and camelid eye are detailed. Restraint techniques and usage of local anesthetics to facilitate examination are described. Common examination findings and their significance are discussed. Finally, therapeutic options for keratoconjunctivitis and uveitis are explored. A complete ocular examination of ruminants is often not performed in the field because of lack of time, lack of appropriate facilities, and/or lack of equipment. Although individual ophthalmic examinations are not frequently performed as part of a herd health program, they can be of value in select cases. Ocular manifestations of systemic diseases may assist the clinician in establishing a diagnosis on the farm and for little additional cost. For patients with a specific ocular complaint, a complete ophthalmic examination is critical. After completion of the examination and arrival at a diagnosis, one must also be cognizant of the therapeutic regimens that are appropriate for use in ruminants, particularly animals that may be used for meat or milk.

Rhombencephalitis Caused by Listeria monocytogenes in Humans and Ruminants: A Zoonosis on the Rise?

Listeriosis is an emerging zoonotic infection of humans and ruminants worldwide caused by Listeria monocytogenes (LM). In both host species, CNS disease accounts for the high mortality associated with listeriosis and includes rhombencephalitis, whose neuropathology is strikingly similar in humans and ruminants. This review discusses the current knowledge about listeric encephalitis, and involved host and bacterial factors. There is an urgent need to study the molecular mechanisms of neuropathogenesis, which are poorly understood. Such studies will provide a basis for the development of new therapeutic strategies that aim to prevent LM from invading the brain and spread within the CNS.

Avaliação dos reflexos espinhais em cordeiros da raça Suffolk

Fez-se a avaliação qualitativa e semiquantitativa dos reflexos espinhais em ovinos, utilizando-se 51 animais da raça Suffolk, machos e fêmeas, entre quatro e cinco meses de idade. Usaram-se os reflexos bilaterais dos membros torácicos, extensor carpo-radial, bicipital, tricipital e flexor, e pélvicos, isquiático, gastrocnêmio, patelar, tibial cranial e flexor, sendo zero indicativo de ausência de reflexo, 1= reflexo discreto e 2= reflexo evidente. Nos membros torácicos, as melhores respostas foram obtidas no flexor (99,0%) e no extensor carpo-radial (87,3%), seguidos de valores menos expressivos no bicipital (11,8%) e no tricipital (2,0%), com grau 2 de avaliação. Nos membros pélvicos, todos os ovinos produziram respostas em grau 2 para o reflexo flexor. Verificam-se também respostas evidentes nos reflexos patelar (98,0%) e isquiático (81,4%). Apenas 20,6% dos animais apresentaram resposta evidente ao reflexo tibial cranial, e nenhum ovino respondeu ao reflexo gastrocnêmio de forma satisfatória.

Clinical and pathological findings in a goat with cerebral gliomatosis

This report describes a buck with cerebral gliomatosis. The animal was severely apathetic to somnolent. Neurological examination revealed generalised ataxia and hyper-metria of the fore limbs. There was bilateral mydriasis and severely decreased menace and pupillary light reflexes. Sensitivity to pricking with a needle was markedly reduced over the entire body. There was a delayed response to adduction, abduction and crossing of the limbs and rocking of the animal. Examination of cerebrospinal fluid indicated mild mixed-cell inflammation. Based on all of the findings, an abscess or tumour of the central nervous system with localisation in the cerebrum was suspected. Because of the grave prognosis, the goat was euthanased and a post mortem examination performed. No macroscopic abnormalities were seen in any of the organs including the brain. Histologically, there was extensive diffuse glial cell hyperplasia in the white matter of the cerebral hemispheres and in the brain stem.

Brainstem and cranial nerve abnormalities: listeriosis, otitis media/interna, and pituitary abscess syndrome

This article reviews three disorders associated with multiple asymmetric cranial nerve deficits in ruminants: encephalitic listeriosis,otitis media/interna, and pituitary abscess syndrome. Emphasis is placed on encephalitic listeriosis, an infectious disease of the brainstem and cranial nerves caused by Listeria monocytogenes. The epidemiology, pathophysiology, clinical manifestations, diagnosis,and treatment of encephalitic listeriosis are reviewed, and differences between cattle and small ruminants are noted. Physical and neurologic examination findings that distinguish otitis media/interna and pituitary abscess syndrome from encephalitic listeriosis are highlighted.