Pulmonary lesions in sheep following experimental infection by Ehrlichia phagocytophilia and Chlamydia psittaci

Munro, Ranald; Hunter, AR; Mackenzie, George M.; McMartin, D.A.

doi:10.1016/0021-9975(82)90047-0

Cited by 31 publications

(10 citation statements)

References 9 publications

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“…It remains to be established where the organism multiplies before it is detected in the peripheral blood 2–4 days after experimental infection, 1 and the sites of persistence during in‐between periods of recurrent bacteremia remain to be established. However, during acute bacteremia the organism has been demonstrated in the alveolar macrophages, Küpffer cells, and other tissue macrophages 1,69,70 . Moreover, there is some evidence to suggest that the organism may be present in the lungs before its detection in the blood 71…”

Section: Target Cellsmentioning

confidence: 99%

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Anaplasma phagocytophilum in Ruminants in Europe

Woldehiwet

2006

Annals of the New York Academy of Sciences

114

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The agent that causes tick-borne fever (TBF) in sheep was first described in 1940, 8 years after the disease was first recognized in Scotland. The same agent was soon shown to cause TBF in sheep and pasture fever in cattle in other parts of the UK, Scandinavia, and other parts of Europe. After the initial use of the name Rickettsia phagocytophila, the organism was given the name Cytoecetes phagocytophila to reflect its association with granulocytes and its morphological similarity with Cytoecetes microti. This name continued to be used by workers in the UK until the recent reclassification of the granulocytic ehrlichiae affecting ruminants, horses, and humans as variants of the same species, Anaplasma phagocytophilum. TBF and pasture fever are characterized by high fever, recurrent bacteremia, neutropenia, lymphocytopenia, thrombocytopenia, and general immunosuppression, resulting in more severe secondary infections such as tick pyemia, pneumonic pasteurellosis, listeriosis, and enterotoxemia. During the peak period of bacteremia as many as 90% of granulocytes may be infected. The agent is transmitted transtadially by the hard tick Ixodes ricinus, and possibly other ticks. After patent bacteremia, sheep, goats, and cattle become persistently infected "carriers," perhaps playing an important role in the maintenance of infection, in the flock/herd. Little is known about how efficiently ticks acquire and maintain infection in ruminant populations or whether "carrier" domestic ruminants play an important role as reservoirs of infection, but deer, other free-living ruminants, and wild rodents are also potential sources of infection. During the late 1990s serological evidence of infection of humans was demonstrated in several European countries, creating a renewed interest and increased awareness of the zoonotic potential of TBF variants. More recently, a few cases of human granulocytic anaplasmosis (HGA) have been reported in some European countries, but it remains to be established whether the variants causing HGA in Europe are genetically and biologically different from those causing TBF in ruminants. TBF is readily diagnosed by demonstrating intracytoplasmic inclusions in peripheral blood granulocytes or monocytes of febrile animals or by detecting specific DNA by polymerase chain reaction (PCR), and TBF variants of A. phagocytophilum can be cultivated in tick cell lines, but the differentiation of TBF variants from HGA variants awaits further investigations.

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Section: Target Cellsmentioning

confidence: 99%

“…However, during acute bacteremia the organism has been demonstrated in the alveolar macrophages, Küpffer cells, and other tissue macrophages. 1,69,70 Moreover, there is some evidence to suggest that the organism may be present in the lungs before its detection in the blood. 71…”

Section: Target Cellsmentioning

confidence: 99%

Anaplasma phagocytophilum in Ruminants in Europe

Woldehiwet

2006

Annals of the New York Academy of Sciences

114

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“…Persistent infections have been reported in mice and rats (Telford et al, 1996;Castro et al, 2001), but some studies have indicated that the primary bacteraemia in man, horses and dogs infected with the HGA variants is brief and that persistent infections are uncommon (Nyindo et al, 1978;Choi et al, 2007). There have been few studies investigating persistent infections in people infected with HGA variants, but there are reported cases of elevated antibody titres lasting for several months (AgueroRosenfeld et al, 1996;Bakken et al, 1996), suggesting persistent infections.…”

Section: Persistent Ovine Anaplasma Phagocytophilum Infectionmentioning

confidence: 90%

“…During acute bacteraemia the organism has been demonstrated in alveolar macrophages, Kupffer cells and other tissue macrophages (Munro et al, 1982;Lepidi et al, 2000). One study in horses infected with HGA variants detected the agent by PCR in muscles, fascia and other poorly vascularized connective tissues several days after experimental infection (Chang et al, 1998), but the study did not provide clear evidence to suggest that cells other than granulocytes or monocytes/macrophages were harbouring infection.…”

Section: Persistent Ovine Anaplasma Phagocytophilum Infectionmentioning

confidence: 96%

Recurrent Bacteraemia in Sheep Infected Persistently with Anaplasma phagocytophilum

Thomas

Birtles

Radford

et al. 2012

Journal of Comparative Pathology

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“…Cytoplasmic inclusions appear first in eosinophils, then neutrophils, and finally monocytes, over a period of 7 days, and inclusions may be detected in neutrophils for 2-3 weeks after infection [43]. E. phagocytophila enters and multiplies in polymorphonuclear cells of the peripheral circulation [44] but, following experimental infection, has also been detected in alveolar macrophages and Kupffer cells [45]. E. phagocytophila enters host cells by endocytosis and is found within endocytic vacuoles [46] containing one or more organisms (Fig.…”

Section: Pathogenesis and Pathologymentioning

confidence: 99%

Granulocytic ehrlichiosis: an emerging or rediscovered tick-borne disease?

Ogden

Woldehiwet

Hart

1998

Journal of Medical Microbiology

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The Ehrlichieae are gram-negative obligately intracellular bacterial pathogens. They can be divided into at least three genogroups on the basis of 16s rRNA gene sequences, but are also classified by target cell specificity. A group of granulocytic ehrlichiae primarily infect neutrophils and fall into genogroup 11. The granulocytic ehrlichiae are subdivided by their target hosts, i.e., Ehdichiaphagocytophila in cattle and sheep, E. equi in horses, and the agents of human (HGE) and llama (LGE) granulocytic ehrlichioses. However, these subdivisions may give a false impression, as all these species are closely related both antigenically and on the basis of 16s rRNA operon sequence. In addition, crossspecies transmission can occur naturally or by experimental infection. The vectors for these granulocytic ehrlichiae are hard-bodied ixodid ticks, and the reservoir hosts are probably wild rodents, deer and sheep. In each host, this illness presents as a febrile disease which can be followed by immunosuppression leading to secondary infections.

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Pulmonary lesions in sheep following experimental infection by Ehrlichia phagocytophilia and Chlamydia psittaci

Cited by 31 publications

References 9 publications

Anaplasma phagocytophilum in Ruminants in Europe

Anaplasma phagocytophilum in Ruminants in Europe

Recurrent Bacteraemia in Sheep Infected Persistently with Anaplasma phagocytophilum

Granulocytic ehrlichiosis: an emerging or rediscovered tick-borne disease?

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