Epidemiological studies on Listeriosis in sheep

Younis, Emad; Elsawalhy, Ahmed; Soumaya, E. A.; El-Beskawy, M. A. A.

doi:10.21608/jvmr.2020.77591

Cited by 3 publications

(6 citation statements)

References 19 publications

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“…The variations in clinical manifestations of the disease are attributed to the site affected in nervous system (medulla, pons, cerebellum, cerebrum or anterior spinal cord) and impairment of cranial nerves (Brugere-Picoux. 2008;Younis et al, 2010). The histopathological lesions observed in this study are in conformity to previous observations by Hamidi et al, (2020) and Kumar et al, (2007) where marked perivascular cuffing comprising of mononuclear cells, polymorphonuclear leukocytes forming abscesses and congested meninges with infiltration of mono nuclear cells were evidenced.…”

Section: Discussionsupporting

confidence: 92%

“…This was a severe outbreak indicated by a high case fatality rate which was in line with a previous report by Younis et al, (2010). Despite the low mortality in the entire population, significantly high mortality rate was observed in goats above one year of age.…”

Section: Discussionsupporting

confidence: 91%

“…Encephalitic Listeriosis was predominantly observed wherein few cases were manifested together with either septicaemic form or reproductive form. The septicaemic form was clearly indicated by the necropsy findings in liver (multiple necrotic foci) and spleen and few of the cases encountered with abortion in pregnant does were suggestive of reproductive Listeriosis.Encephalitic form was commonly reported in several outbreaks from various countries (Barman et al, 2020;Borku et al, 2006;Younis et al, 2010). The clinical presentation with encephalitic Listeriosis was similarly documented in many other studies (Braun et al, 2002;Hamidi et al, 2020;Kumar et al, 2007) which could facilitate on a rapid clinical diagnosis of the disease.…”

Section: Discussionmentioning

confidence: 61%

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Emergence of clinically suspected listeriosis in goats: a sporadic outbreak in Jaffna district, Sri Lanka

Amutha,

Briyangari,

Prabaharan

2023

Sri Lanka Vet. J.

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Listeriosis is an infectious disease affecting ruminants and a serious foodborne illness in humans. Index cases with neurological signs suspected of Listeriosis were reported from ten Veterinary ranges of Jaffna District in August 2021. Field investigation with 937 animals from 262 farms revealed the characteristic clinical manifestations of the disease. The brain samples of dead animals were subjected to microbiological and histopathological analysis and confirmed as Listeriosis. Antibiotic sensitivity test was performed using disc diffusion method and amoxicillin, tetracycline, enrofloxacin and trimethoprim/ sulfamethoxazole were found to be sensitive to the isolates of suspected Listeria monocytogenes.The outbreak affected the goats regardless of breed and sex with a high incidence in goats of 1-3 years of age. Encephalitic form of Listeriosis was primarily observed with a high case fatality rate (77.8%). The mortality rate was high (84%) in adult goats and a low recovery rate (22.22%) was recorded in the overall population despite the routine therapeutic interventions. However, preventive measures adapted to control the outbreak within and outside the district were a success. This is the first report of the emergence of a Listeriosis outbreak in Jaffna District and it highlights the need to initiate preventive strategies for the future occurrence of Listeriosis as it is a possible threat to public health.

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Section: Discussionsupporting

confidence: 92%

Section: Discussionsupporting

confidence: 91%

Section: Discussionmentioning

confidence: 61%

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Emergence of clinically suspected listeriosis in goats: a sporadic outbreak in Jaffna district, Sri Lanka

Amutha,

Briyangari,

Prabaharan

2023

Sri Lanka Vet. J.

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“…All affected sheep more than 1-year-old [17]. On the other hand, young animals can be frequently affected when they are losing and changing their teeth, which leads to lesions in the gums that the bacteria can penetrate [20]. In the present report, the age of the sheep ranged from 5 to 6 months.…”

Section: Discussionmentioning

confidence: 63%

“…This suggests that the disease depends on more the environmental conditions than on the age of the animals. In sheep of up to 6-month-old, it was observed that nervous manifestations of listeriosis are more pronounced than in adult animals [20], and the lethality rate was significantly higher when compared to that in sheep older than 6 months [9].…”

Section: Discussionmentioning

confidence: 93%

Listeriosis Outbreak in Sheep Raised in Feedlots in the Southern Region of Rio Grande do Sul State, Brazil

Ribeiro¹,

Scheid²,

Marques³

et al. 2022

Acta Scientiae. Vet.

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Background: A listeriosis outbreak in a sheep fattening feedlot in the Southern Region of Rio Grande do Sul State, Brazil is described. This disease is caused by Listeria monocytogenes and represents a risk to public health since it affects not only ruminants but also humans. This agent is widely spread in the environment, such as in the soil and water. It is also found in decaying vegetable matter and the feces and fluids of domestic animals. The aim of this study was to describe a listeriosis outbreak in sheep raised in feedlots, its epidemiology, and to establish the importance of this disease in this type of sheep management system, evaluate the possible sources of infection, and suggest ways to control it.Cases: Sheep were kept in a 2-sector shed, one with east solar orientation and the other with west solar orientation, the latter with free access to domestic birds. Sheep were fed silage and concentrate. Seven sheep were affected, 5 died and 2 recovered. Clinically, the sheep displayed loss of balance, excessive drooling, and tremors; one exhibited circling, head deviation, apathy, nystagmus, lateral recumbency, paddling, and labored breathing. At necropsy, macroscopic lesions were not found, and histologically several micro-abscesses and perivascular cuffs with lymphocytes, macrophages, and neutrophils were present in the brain stem. Listeria monocytogenes suspected colonies were observed in the microbiological culture, and the bacteria was identified by biochemical analysis. The immunohistochemistry test in brain stem sections was positive for the antibody BD DifcoTM Listeria O Antiserum Poly Serotypes 1 and 4.Discussion: A listeriosis outbreak in a feedlot sheep was confirmed through epidemiological findings, histological lesions, bacterial culture, and immunohistochemistry analysis. This infection is frequent in sheep fed silage of poor quality or other food with improper storage and lack of hygiene. In the present outbreak, the bacteria were isolated from silage. However, it is likely that domestic birds, which were raised in the same place and had free access to the west sector of the feedlot, were the initial source of infection, because the sheep from the opposite sector (east) did not get ill. The disease caused by environmental contamination or through contact with fluids and feces of ducks, chickens, cattle, and pigs has already been described in outbreaks that occurred in the central region of Rio Grande do Sul. Sheep aggregation in feedlot systems is also a favorable factor for the development of the bacteria and the occurrence of outbreaks because the accumulation of feces and urine cause humidity on the stalls. This allows outbreaks to occur in other seasons of the year, such as in the outbreak reported herein. The exchange of silage that served as food for sheep was another control measure, and new cases were not reported 8 months after these procedures were taken. In the outbreak studied, 2 sheep that exhibited clinical signs were treated with oxytetracycline and recovered. Some authors report that treatment for listeriosis is inefficient because neurological lesions are irreversible. Nonetheless, other studies have reported the recovery of some animals when they were treated with oxytetracycline or a combination of oxytetracycline and dexamethasone or ampicillin and gentamicin like in the outbreak described in this paper.Keywords: Listeria monocytogenes, central nervous system, silage, feedlot, ovine.

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Simulation of the Squeeze Film Damping in a RF MEMS Switch

Huang

Wang

2013

AMM

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Two different dynamic models have been presented to investigate the transient mechanical response of a RF MEMS switch under the effects of squeeze-film damping based on a modified Reynolds equation. Both the perforated and non-perforated structures are built for comparison. The models include realistic dimensions. The surface pressure, the damping force, and the tip displacement are simulated in three different ambient pressures, such as 500Pa, 5kPa, and 0.05MPa. The result shows that the increased damping leads to a substantial decrease in oscillation with increasing pressure for the non-perforated structure. Compared with the perforated pad, there is a much larger damping force acts on the non-perforated surface, and an obvious decrease in damping force with increasing pressure.

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Epidemiological studies on Listeriosis in sheep

Cited by 3 publications

References 19 publications

Emergence of clinically suspected listeriosis in goats: a sporadic outbreak in Jaffna district, Sri Lanka

Emergence of clinically suspected listeriosis in goats: a sporadic outbreak in Jaffna district, Sri Lanka

Listeriosis Outbreak in Sheep Raised in Feedlots in the Southern Region of Rio Grande do Sul State, Brazil

Simulation of the Squeeze Film Damping in a RF MEMS Switch

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