Babesia divergens experimental infection of spleen-intact sheep results in long-lasting parasitemia despite a strong humoral response: Preliminary results

Moreau, Emmanuelle; Jouglin, Maggy; Chauvin, Alain; Malandrin, Laurence

doi:10.1016/j.vetpar.2009.08.021

Cited by 10 publications

(7 citation statements)

References 27 publications

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“…In domestic ruminants, RBC culture has a detection threshold for B. divergens of about 10 27 % of parasitemia, corresponding to about 10 parasites/ml of blood (Malandrin et al, 2004). There may be persistence of infection even at this low level, as demonstrated in sheep experimentally infected with B. divergens and experiencing a persistent IgG response, despite no currently detectable parasites by RBC culture (Moreau et al, 2009). In the present enzootic context, it is probable that multiple infections occur and that most animals have encountered one or both species B. capreoli and B. venatorum.…”

Section: Discussionmentioning

confidence: 99%

Antibody Prevalence and Molecular Identification of Babesia Spp. In Roe Deer in France

Bastian

Jouglin

Brisseau

et al. 2012

Journal of Wildlife Diseases

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ABSTRACT:In a region-wide serologic study carried out in 2004 on free-ranging hunted roe deer in various landscapes, we found that 58% of the animals (237 out of 406) were antibody positive for Babesia divergens antigen. Serologic and infection status was also analyzed for 327 roe deer livetrapped in two fenced forest areas over 5 yr . For two consecutive years during this period, 92 and 94% of the deer in these closed populations were antibody-positive for B. divergens. Babesia spp. were isolated in autologous red blood cell culture for 131 of the trapped animals (40%). Molecular typing was done on 76 isolates with polymerase chain reaction (PCR)-restriction fragment length polymorphism methods targeted at the 18S ribosomal subunit gene (18 isolates) and the Bd37 gene coding for a merozoïte surface antigen implicated in a protective response (60 isolates). Results indicated continuous cocirculation of B. capreoli and B. venatorum in both forests and possible coinfection of animals with both species. No infection with B. divergens was detected. Fifteen isolates were confirmed to be B. capreoli by sequencing part of the 18S rRNA gene. Using PCR detection of the Bd37 gene, all nine isolates of B. venatorum in this study were negative, whereas the 15 confirmed and 50 putative B. capreoli isolates showed very variable restriction profiles, distinct from those known for Bd37 in B. divergens. Two isolates showed conflicting results, suggestive of mixed infection.

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Section: Discussionmentioning

confidence: 99%

Antibody Prevalence and Molecular Identification of Babesia Spp. In Roe Deer in France

Bastian

Jouglin

Brisseau

et al. 2012

Journal of Wildlife Diseases

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“…To pinpoint the proteins involved in the invasion process (i.e. those potentially secreted and thus in contact with the immune system during natural infection), we chose to use sera from two calves experimentally infected with B. divergens strains C139 and IV35 respectively [34] and from four sheep experimentally infected with B. divergens strain Rouen 87 [35]. To avoid the production of antibodies against RBC proteins, the calves and sheep were infected with parasites cultivated in vitro in their own erythrocytes.…”

Section: Methodsmentioning

confidence: 99%

The invasion process of bovine erythrocyte by Babesia divergens: knowledge from an in vitro assay

Sun

Moreau

Chauvin

et al. 2011

Vet Res

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Babesia divergens is a tick-transmitted apicomplexan parasite for which asexual multiplication in its vertebrate hosts is restricted to erythrocytes. Current knowledge of invasion of these target cells is limited. An efficient in vitro invasion assay was set up to gain access to this information. Parasites prepared from infected RBC, lysed by electroporation, and mixed with bovine RBC in a selected synthetic medium (RPMI 1640 supplemented with calcium) were able to establish subsequent cultures with parasitemia ranging from 6 to 14%. Free parasites remaining in the invasion medium could be eliminated by Percoll gradient and culture could be pursued with the freshly invaded erythrocytes. In this way, the invasion time window could be shortened to obtain a synchronised start of the culture or to study the kinetics of invasion. With this assay we demonstrate that 1) erythrocyte invasion by B. divergens is a rapid process since 70% of the invasion-competent parasites invaded the RBC in less than 45 s; 2) all invasion-competent parasites achieved invasion within 10 min of contact; 3) one erythrocyte could be invaded concomitantly by two merozoites; 4) despite a synchronous start, the parasite population evolved heterogeneously resulting in a progressive loss of synchronisation. Western blot analysis of proteins collected from invasion medium were performed with sera from animals experimentally infected with B. divergens and highlighted several proteins. The dose-dependent, inhibitory effects of these sera on B. divergens invasion suggest that these proteins might be involved in the invasion process. Further investigations are required for their characterisation.

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“…The presence of erytrophagocytosis can be observed in smears from the spleen and liver in sick animals such as dogs [ 37 ] and cattle [ 35 ]. Sheep have been evaluated as an experimental animal model of bovine babesiosis caused by B. divergens as they do not show evident clinical signs but develop a robust humoral response [ 38 ]. The spleen has a critical function in controlling clinical disease and experimentally infected splenectomised animals rapidly develop parasitemia and clinical signs [ 38 ].…”

Section: Babesiamentioning

confidence: 99%

Anaemia in Sheep Caused by Babesia and Theileria Haemoparasites

Villanueva‐Saz

Borobia

Fernández

et al. 2022

Animals

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Piroplasmoses in sheep are caused by vector-borne apicomplexan protozoa, Babesia and Theileria. Different species are responsible for the disease; some species are more pathogenic than others and have a worldwide distribution. In this sense, these causative agents can cause anaemia in flocks. In general, these vector-borne diseases infect small ruminants and cause host-mediated pathology. In the case of Babesia species, a combination of different mechanisms is involved: red blood cell lysis due to intracellular parasite multiplication, activation of biogenic amines and the coagulation system with the possibility of disseminated intravascular coagulation. By contrast, less information is available on the different immunopathogenic mechanisms involved in the development of anaemia in sheep with theileriosis. However, the mechanisms of pathogenic action in theileriosis are similar to those studied in babesiosis. Diagnosis is based on compatible clinical signs, laboratory findings, specific diagnostic tests and the presence of the tick vector. Some of these tests detect the causative agent itself, such as direct identification by light microscopy and molecular analysis. In contrast, other tests detect the sheep’s immune response to the organism by serology. Both diseases pose a significant diagnostic challenge for veterinary practitioners around the world. This review presents the most frequent clinical signs, pathogenesis and clinicopathological findings, diagnosis.

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Babesia divergens experimental infection of spleen-intact sheep results in long-lasting parasitemia despite a strong humoral response: Preliminary results

Cited by 10 publications

References 27 publications

Antibody Prevalence and Molecular Identification of Babesia Spp. In Roe Deer in France

Antibody Prevalence and Molecular Identification of Babesia Spp. In Roe Deer in France

The invasion process of bovine erythrocyte by Babesia divergens: knowledge from an in vitro assay

Anaemia in Sheep Caused by Babesia and Theileria Haemoparasites

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