Response of sheep to experimental concurrent infection with tick-borne fever (Cytoecetes phagocytophila) and louping-ill virus

Reid, H.W.; Buxton, D.; Pow, I.; Brodie, TA; Holmes, P.H.; Urquhart, G.M.

doi:10.1016/s0034-5288(18)30572-1

Cited by 30 publications

(18 citation statements)

References 21 publications

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“…This is thought to contribute to the persistence of LIV even when control measures in sheep, such as vaccination, are applied. Experimental studies in support of field observations have shown that duel infection with LIV and Anaplasma phagocytophilum (see below) can increase the severity of disease in sheep (101).…”

Section: Louping Illmentioning

confidence: 78%

Emerging Threats to Animals in the United Kingdom by Arthropod-Borne Diseases

et al. 2020

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Worldwide, arthropod-borne disease transmission represents one of the greatest threats to public and animal health. For the British Isles, an island group on the northwestern coast of continental Europe consisting of the United Kingdom (UK) and the Republic of Ireland, physical separation offers a barrier to the introduction of many of the pathogens that affect animals on the rest of the continent. Added to this are strict biosecurity rules at ports of entry and the depauperate vector biodiversity found on the islands. Nevertheless, there are some indigenous arthropod-borne pathogens that cause sporadic outbreaks, such as the tick-borne louping ill virus, found almost exclusively in the British Isles, and a range of piroplasmid infections that are poorly characterized. These provide an ongoing source of infection whose emergence can be unpredictable. In addition, the risk remains for future introductions of both exotic vectors and the pathogens they harbor, and can transmit. Current factors that are driving the increases of both disease transmission and the risk of emergence include marked changes to the climate in the British Isles that have increased summer and winter temperatures, and extended the period over which arthropods are active. There have also been dramatic increases in the distribution of mosquito-borne diseases, such as West Nile and Usutu viruses in mainland Europe that are making the introduction of these pathogens through bird migration increasingly feasible. In addition, the establishment of midge-borne bluetongue virus in the near continent has increased the risk of wind-borne introduction of infected midges and the inadvertent importation of infected cattle. Arguably the greatest risk is associated with the continual increase in the movement of people, pets and trade into the UK. This, in particular, is driving the introduction of invasive arthropod species that either bring disease-causing pathogens, or are known competent vectors, that increase the risk of disease transmission if introduced. The following review documents the current pathogen threats to animals transmitted by mosquitoes, ticks and midges. This includes both indigenous and exotic pathogens to the UK. In the case of exotic pathogens, the pathway and risk of introduction are also discussed.

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Section: Louping Illmentioning

confidence: 78%

Emerging Threats to Animals in the United Kingdom by Arthropod-Borne Diseases

et al. 2020

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“…Regardless, the combined effects of enhanced MMP, cytokine, and chemokine release and impaired neutrophil phagocytosis with coinfection could collectively lead to enhanced entry of B. burgdorferi into the CNS and other tissues, potentially worsening clinical manifestations of Lyme disease. A precedent for A. phagocytophilum-enhanced clinical disease in the CNS exists in sheep coinfected with louping ill virus, a tick-transmitted flavivirus of the tick-borne encephalitis group (11,37), although the mechanism is not understood.…”

Section: Discussionmentioning

confidence: 99%

Anaplasma phagocytophilum - Borrelia burgdorferi Coinfection Enhances Chemokine, Cytokine, and Matrix Metalloprotease Expression by Human Brain Microvascular Endothelial Cells

Grab

Nyarko

Barat

et al. 2007

Clin Vaccine Immunol

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“…The strain diversity that occurs in A. phagocytophilum [23] can vary disease severity and antibody response in sheep [24]. It has been shown that TBF can have an aggravating effect on simultaneous louping-ill infection in sheep [25], the louping-ill virus and TBEV being closely related flaviviruses. Hence, it can be hypothesized that the reduced immunity of TBF-affected dairy sheep (manifested by a less pronounced antibody response to TBEV infection) generates the conditions for more severe viremia with enhanced virus excretions in TBEV co-infection.…”

Section: Discussionmentioning

confidence: 99%

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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Response of sheep to experimental concurrent infection with tick-borne fever (Cytoecetes phagocytophila) and louping-ill virus

Cited by 30 publications

References 21 publications

Emerging Threats to Animals in the United Kingdom by Arthropod-Borne Diseases

Emerging Threats to Animals in the United Kingdom by Arthropod-Borne Diseases

Anaplasma phagocytophilum - Borrelia burgdorferi Coinfection Enhances Chemokine, Cytokine, and Matrix Metalloprotease Expression by Human Brain Microvascular Endothelial Cells

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

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