Ehrlichia (Cytoecetes) phagocytophila Predisposes to Severe Contagious Ecthyma (Orf ) in Lambs

Gokce, H. I.; Woldehiwet, Z.

doi:10.1053/jcpa.1999.0320

Cited by 10 publications

(7 citation statements)

References 21 publications

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“…Unfortunately, no whole-blood specimens were available for confirming chronic infection and PCR examination of sera ultracentrifuge concentrates yielded inconclusive results. The immunosuppressive effect of A. phagocytophilum infection, impairing the host's resistance to secondary pathogens, is a common complication [18][19][20][21]. The levels of antibodies produced in TBF victims against a concurrent antigen challenge would be lower than in healthy animals [22]; this corresponds with our observation of the negative correlation of the anti-TBEV and anti-A.…”

Section: Discussionsupporting

confidence: 69%

High seroprevalence of granulocytic ehrlichiosis distinguishes sheep that were the source of an alimentary epidemic of tick-borne encephalitis

Zeman¹,

Januska²,

Orolinova³

et al. 2004

Wien Klin Wochenschr

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A sheep herd from which contaminated cheese was produced, causing 21 cases of alimentary tick-borne encephalitis (TBE) in human beings, was tested serologically for the presence of specific antibodies against both the TBE virus (TBEV) and Anaplasma phagocytophilum, the cause of tick-borne fever (TBF) in ruminants, and compared with three other herds variously exposed to tick bites but without any TBE history. Virus-neutralisation (VN) with the TBEV strain Hypr and CV-1 cells was used in TBE tests, and indirect immunofluorescence assay (IFA) with neutrophils from goats experimentally infected with A. phagocytophilum was used for TBF testing. In 13 sheep from the incriminated herd (N =41), VN titres ranging from 1/4 to 1/128 traced previous TBE infection and all sheep had elevated titres of A. phagocytophilum antibodies ranging from 1/80 to 1/5120 in IFA, whereas two other herds (N = 8 and 9) were seronegative for TBEV and had significantly lower levels of A. phagocytophilum antibodies, corresponding to a lesser challenge from TBF. A control herd (N = 10) that was grazed on tick-free meadows in north Norway was completely seronegative. The respective distributions of positive titres of A. phagocytophilum and TBEV antibodies in the incriminated herd were not mutually random; the animals with higher anti-A. phagocytophilum titres tended to have lower anti-TBEV titres and vice versa (Spearman correlation coeff. =-0.86, p< or =0.01). The authors hypothesize that the immunosuppressive effect of TBF co-infection in sheep could be a contributory cause of TBE-virus contamination of milk, an aspect of TBE epidemiology that has not been considered thus far.

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Section: Discussionsupporting

confidence: 69%

High seroprevalence of granulocytic ehrlichiosis distinguishes sheep that were the source of an alimentary epidemic of tick-borne encephalitis

Zeman¹,

Januska²,

Orolinova³

et al. 2004

Wien Klin Wochenschr

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“…Previous studies of both humans and animals have indicated that A. phagocytophilum can influence the pathology of a range of co-infecting parasites (Reid et al . 1986; Gokce and Woldehiwet, 1999; Krause et al . 2002), which is not unexpected given that it infects neutrophils.…”

Section: Discussionmentioning

confidence: 99%

Parasite interactions in natural populations: insights from longitudinal data

et al. 2008

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The physiological and immunological state of an animal can be influenced by current infections and infection history. Consequently, both ongoing and previous infections can affect host susceptibility to another parasite, the biology of the subsequent infection (e.g. infection length) and the impact of infection on host morbidity (pathology). In natural populations, most animals will be infected by a succession of different parasites throughout the course of their lives, with probably frequent concomitant infections. The relative timing of different infections experienced by a host (i.e. the sequence of infection events), and the effects on factors such as host susceptibility and host survival, can only be derived from longitudinal data on individual hosts. Here we review some of the evidence for the impact of co-infection on host susceptibility, infection biology and pathology focusing on insights obtained from both longitudinal studies in humans and experiments that explicitly consider the sequence of infection. We then consider the challenges posed by longitudinal infection data collected from natural populations of animals. We illustrate their usefulness using our data of microparasite infections associated with field vole (Microtus agrestis) populations to examine impacts on susceptibility and infection length. Our primary aim is to describe an analytical approach that can be used on such data to identify interactions among the parasites. The preliminary analyses presented here indicate both synergistic and antagonistic interactions between microparasites within this community and emphasise that such interactions could have significant impacts on host-parasite fitness and dynamics.

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“…16,17 Secondary bacterial infections have also previously been shown to increase the severity and duration of orf lesions in lambs. 18,19 In another study, severe lesions were produced in lambs concurrently infected with D congolensis and orf virus, but not with either agent alone. 20 We were not able to demonstrate a Dermatophilus infection in these sheep, and the significance of the Staphylococcus bacteria isolated from 2 of the sheep is unknown.…”

Section: Resultsmentioning

confidence: 97%

“…Sheep experimentally infected with Ehrlichia phagocytophila before exposure to orf virus have increased severity and duration of skin lesions when compared with sheep that have not been infected with E phagocytophila. 19 This rickettsial organism invades polymorphonuclear leukocytes and is known to suppress cellmediated immunity. 19 We previously reported an atypical parapoxvirus infection in a sheep after extensive cutaneous thermal injury, 3 which would also induce marked immunosuppression.…”

Section: Resultsmentioning

confidence: 99%

“…19 This rickettsial organism invades polymorphonuclear leukocytes and is known to suppress cellmediated immunity. 19 We previously reported an atypical parapoxvirus infection in a sheep after extensive cutaneous thermal injury, 3 which would also induce marked immunosuppression. Regardless of the mechanism for these atypical parapoxvirus lesions, the prognosis for recovery should be considered very poor.…”

Section: Resultsmentioning

confidence: 99%

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Atypical Parapoxvirus Infection in Sheep

Smith

Scherba

Constable

et al. 2002

Veterinary Internal Medicne

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This report describes the clinical and laboratory findings for 5 sheep from 3 different flocks with extensive proliferative skin lesions grossly resembling warts on the distal limbs. The lesions affected the front and rear extremities in all sheep, and 2 sheep also had lesions around the head. The sheep exhibited signs of pain when the lesions were touched, and most sheep were reluctant to move. Various empirical treatments, including systemic antibiotics, topical antibiotics, and antifungal ointments, were administered without clinical improvement. Diagnostic tests including skin biopsy and histopathology, examination of skin scrapings, bacteriology, mycology, electron microscopy of lesions, and immunohistochemical analysis demonstrated that the lesions were the result of parapoxvirus infection. All 5 animals were euthanized either because of the lack of resolution of clinical signs or a decision by the owner. These animals illustrate an atypical presentation of parapoxvirus infection in sheep (orf, contagious ecthyma, and scabby mouth). The infection appeared to be minimally contagious; however, the lesions did not spontaneously resolve. This appears to be the 1st report of such lesions in multiple sheep in North America, although similar lesions have been reported in Israel and the United Kingdom.

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Ehrlichia (Cytoecetes) phagocytophila Predisposes to Severe Contagious Ecthyma (Orf ) in Lambs

Cited by 10 publications

References 21 publications

High seroprevalence of granulocytic ehrlichiosis distinguishes sheep that were the source of an alimentary epidemic of tick-borne encephalitis

High seroprevalence of granulocytic ehrlichiosis distinguishes sheep that were the source of an alimentary epidemic of tick-borne encephalitis

Parasite interactions in natural populations: insights from longitudinal data

Atypical Parapoxvirus Infection in Sheep

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