RESUMEN
The development and growth of fish farming are hindered by viral and bacterial infectious diseases, which necessitate effective disease control measures. Furunculosis, primarily caused by Aeromonas salmonicida, stands out as a significant bacterial disease affecting salmonid fish farms, particularly rainbow trout. Vaccination has emerged as a crucial tool in combating this disease. The objective of this experiment was to assess and compare the efficacy and duration of different vaccine protocols against furunculosis in large trout under controlled rearing conditions, utilizing single and booster administrations via intraperitoneal, oral, and immersion routes. Among the various vaccination protocols tested, only those involving intraperitoneal injection, administered at least once, proved truly effective in preventing the expression of clinical signs of furunculosis and reducing mortality rates. A single intraperitoneal administration provided protection for up to 2352°-days, equivalent to approximately 5 months in water at 16 °C. However, intraperitoneal vaccination may lead to reduced growth in the fish due to resultant intraperitoneal adhesions. Additionally, protocols incorporating booster doses via intraperitoneal injection demonstrated efficacy regardless of the administration route of the primary vaccination. Nevertheless, the use of booster vaccinations via the intraperitoneal route did not confer any significant advantage over a single intraperitoneal injection in terms of efficacy.
Asunto(s)
Aeromonas salmonicida , Enfermedades de los Peces , Forunculosis , Infecciones por Bacterias Gramnegativas , Oncorhynchus mykiss , Animales , Oncorhynchus mykiss/inmunología , Forunculosis/prevención & control , Forunculosis/inmunología , Aeromonas salmonicida/inmunología , Enfermedades de los Peces/prevención & control , Enfermedades de los Peces/inmunología , Infecciones por Bacterias Gramnegativas/veterinaria , Infecciones por Bacterias Gramnegativas/prevención & control , Infecciones por Bacterias Gramnegativas/inmunología , Inyecciones Intraperitoneales/veterinaria , Autovacunas/administración & dosificación , Autovacunas/inmunología , Vacunación/veterinaria , Administración Oral , Vacunas Bacterianas/administración & dosificación , Vacunas Bacterianas/inmunologíaRESUMEN
INTRODUCTION: Telerehabilitation (TR) is a promising method for facilitating the delivery and access to post-stroke rehabilitation services. OBJECTIVE: The aim of this study was to explore the acceptability of TR and factors influencing its adoption by individuals with stroke and caregivers. METHODS: A qualitative descriptive approach was used. Six individuals with stroke and three caregivers participated in individual online interviews. An abductive thematic analysis was employed to analyze the qualitative data, using the Unified Theory of Acceptance and Use of Technology 2 (UTAUT-2) model. RESULTS: Participants reported positive experiences with TR, resulting in improvements in functional abilities, such as manual dexterity, balance, and positive interactions with therapists. They found the technology easy to learn and use, facilitating engagement in TR. Participants' prior experiences with technology, along with support from caregivers and therapists, facilitated acceptance and the use of TR. The COVID-19 pandemic also motivated participants to accept TR. However, technical issues, unstable internet connections, and lack of feedback were barriers to the use of TR. CONCLUSION: Despite existing obstacles, TR can be used to provide rehabilitation services for individuals with stroke. Addressing these barriers is necessary to promote the widespread and effective use of TR in the context of stroke recovery.
RESUMEN
Furunculosis caused by Aeromonas salmonicida subsp salmonicida (Ass) is a medically and economically important bacterial disease in salmonid farms that requires therapeutic measures to prevent and control the disease. Evaluation of the effectiveness of traditional measures such as antibiotics or vaccines usually requires infecting fish experimentally. The objective of this study is to develop a method of infectious challenge of large (250-g) Rainbow trout by immersion close to natural infection conditions. We compare mortality, morbidity and anti-Ass antibody production of Rainbow trout following different bathing times (2, 4, 8 and 24 h) at a final bacterial concentration of 106 CFU/mL. One hundred sixty fish divided in five groups corresponding to the 4 bathing times and the non-challenged group were studied. The 24 h contact duration resulted in the infection of all fish, with a mortality rate of 53.25%. The challenged fish developed acute infection with symptoms and lesions (inappetance, altering of swimming behaviour, presence of boils) similar to those observed in furunculosis, and produced antibodies against the bacterium at 4 weeks after challenging, in contrast with the non-challenged group.
Asunto(s)
Aeromonas salmonicida , Aeromonas , Enfermedades de los Peces , Forunculosis , Infecciones por Bacterias Gramnegativas , Oncorhynchus mykiss , Animales , InmersiónRESUMEN
This study presents the occurrence and abundance of Aeromonas antibiotic-resistant bacteria (ARB) and genes (ARGs) isolated from water, biofilm and fish in two commercial trout farms before and one week after flumequine treatment. Wild (WT) and non-wild (NWT) strains were determined for quinolones (flumequine, oxolinic acid and enrofloxacin), oxytetracycline (OXY), florfenicol (FFN), trimethoprim-sulfamethoxazole (TMP) and colistin (COL), and pMAR (presumptive multi-resistant) strains were classified. Forty-four ARGs for the mentioned antibiotics, ß-lactams and multi-resistance were quantified for 211 isolates. BlaSHV-01, mexF and tetE were the dominant ARGs. A greater occurrence and abundance of tetA2, sul3, floR1, blaSHV-01 and mexF were observed for NWT compared to WT. The occurrence of pMAR and NWT Aeromonas for quinolones, OXY, FFN, TMP, COL and ARGs depended on the Aeromonas origin, antibiotic use and the presence of upstream activities. Our results revealed the impact of a flumequine treatment on Aeromonas present on a fish farm through an increase in NWT and pMAR strains. The link between fish and their environment was shown by the detection of identical ARB and ARGs in the two types of samples. There appears to be a high risk of resistance genes developing and spreading in aquatic environments.
RESUMEN
Yersina ruckeri is an enterobacteria responsible for Enteric redmouth disease (ERM), which causes significant economic losses in the aquaculture industry worldwide. Two biotypes have been described within Y. ruckeri: biotype 1 (BT1) and biotype 2 (BT2). Unlike BT1, BT2 is negative for motility and lipase secretion. The emergence of BT2 Y. ruckeri has been associated with disease outbreaks in vaccinated fish in several countries, notably France in the early 2000s. In this study, 15 BT2 strains (14 BT2 strains isolated in France and the BT2 reference strain EX5) were studied to compare the phenotypic characters of the BT1 and BT2 strains and to determine the genetic origin of the emergence of BT2 in France. BT1 bacteria are significantly longer in size than BT2 bacteria (a difference of 0.222 µm). The loss of motility of some French BT2 strains could be due to the loss of their ability to produce flagella caused by three mutations within the fliG, flhC and flgA genes. In the light of these results, the emergence of BT2 Yersinia ruckeri in France is discussed.
Asunto(s)
Enfermedades de los Peces/microbiología , Flagelos/genética , Oncorhynchus mykiss/microbiología , Yersiniosis/veterinaria , Yersinia ruckeri/genética , Animales , Acuicultura , Proteínas Bacterianas/genética , Técnicas de Tipificación Bacteriana/veterinaria , Enfermedades de los Peces/epidemiología , Francia/epidemiología , Mutación , Fenotipo , Yersiniosis/epidemiología , Yersiniosis/microbiología , Yersinia ruckeri/aislamiento & purificaciónRESUMEN
Interleukins have been well described in mice and humans. In large domestic animals the situation is drastically different and there is still a need for further researches aiming at identifying all the homologous interleukins and comparing their functions among species. We performed here a bibliometric analysis of all interleukins described in the literature in various large animal species to identify what is known so far and to underline where there is a need for new studies. Using indicators such as H index but also M quotient, A index, G index, GH ratio, and HG index we ranked 39 interleukins identified so far in bovine, caprine, equine, ovine, and porcine, the main large domestic animals. Indexes and ratio under investigations were higher for IL1, IL2, IL4, IL5, IL6, IL8, IL10, IL12, and IL18 than for other interleukins, particularly in bovine and porcine species and to a certain extent in equine species. Recently discovered interleukins presented low values for the different indexes, quotient, and ratio. Even some "old" interleukins showed low values highlighting the need for further developments in comparative immunology. For instance an interleukin such as IL4 demonstrated variation in its functions between species. In conclusion, this study provides the first bibliometric analysis dedicated to large domestic animal interleukins and underlines the need for more studies to fully determine the structure and the functions of interleukins in other mammal species.
RESUMEN
Babesia sp. BQ1 (Lintan) is one of the parasites isolated from infected sheep in China that belongs to the B. motasi-like phylogenetic group. The rhoptry-associated-protein 1 (rap-1) locus in this group consists of a complex organization of 12 genes of three main types: 6 rap-1a variants intercalated with 5 identical copies of rap-1b and a single 3' ending rap-1c gene. In the present study, transcription analysis performed by standard RT-PCR demonstrated that the three different rap-1 gene types and the four rap-1a variants were transcribed by the parasite cultivated in vitro. Peptides, specific for each rap-1 type gene, were selected in putative linear B-epitopes and used to raise polyclonal rabbit antisera. Using these sera, the same expression pattern of RAP-1 proteins was found in parasites cultivated in vitro or collected from acute infection whereas only RAP-1a67 was detectable in merozoite extracts. However, ELISA performed with recombinant RAP-1a67, RAP-1b or RAP-1c and sera from infected sheep demonstrated that RAP-1a67 is the main RAP-1 recognized during infection, even if some infected sheep also recognized RAP-1b and/or RAP-1c.
Asunto(s)
Babesia/genética , Babesiosis/parasitología , Proteínas Protozoarias/genética , Enfermedades de las Ovejas/parasitología , Animales , Anticuerpos Antiprotozoarios/sangre , Anticuerpos Antiprotozoarios/metabolismo , Babesiosis/sangre , China , Ensayo de Inmunoadsorción Enzimática , Perfilación de la Expresión Génica/veterinaria , Regulación de la Expresión Génica , Variación Genética , Proteínas Recombinantes/metabolismo , Ovinos , Enfermedades de las Ovejas/sangreRESUMEN
BACKGROUND: In China, ovine babesiosis is one of the most important tick-borne haemoparasitic diseases of small ruminants. It has a significant economic impact, and several Babesia motasi-like isolates have been recently shown to be responsible for ovine babesiosis in this country. METHODS: Full-length and C-terminal-truncated forms of the rap-1a61-1 gene of Babesia sp. BQ1 (Lintan) were cloned into the pET-30a plasmid and subsequently expressed as His-fusion proteins. The resulting recombinant RAP-1a proteins (rRAP-1a61-1 and rRAP-1a61-1/CT) were purified and evaluated as diagnostic antigens using Western blot analysis and ELISA. The native Babesia sp. BQ1 (Lintan) RAP-1 protein was recognized using Western blots and IFAT by antibodies that were raised in rabbits against rRAP-1a61-1/CT. The specificity, sensitivity and positive threshold values for rRAP-1a61-1/CT in ELISA were evaluated. RESULTS: Cross-reactivity was observed between rRAP-1a61-1/CT and positive sera for Babesia sp. BQ1 (Lintan), Babesia sp. BQ1 (Ningxian) and Babesia sp. Tianzhu isolates obtained from infected sheep. At one week post-inoculation, a significant increase was observed in the amount of antibodies produced against RAP-1a, and high levels of antibodies against RAP-1a were observed for 3 months (at 84 days p.i.). A total of 3198 serum samples were collected from small ruminants in 54 different regions in 23 provinces of China. These samples were tested using ELISA based on the rRAP-1a61-1/CT protein. The results indicated that the average positive rate was 36.02 %. CONCLUSIONS: The present study suggests that rRAP-1a61-1/CT might be a potential diagnostic antigen for detecting several isolates of B. motasi-like parasites infection.
Asunto(s)
Babesia/aislamiento & purificación , Babesiosis/diagnóstico , Proteínas Protozoarias/metabolismo , Enfermedades de las Ovejas/diagnóstico , Animales , Babesia/inmunología , Babesiosis/parasitología , Ensayo de Inmunoadsorción Enzimática/veterinaria , Proteínas Protozoarias/genética , Pruebas Serológicas/veterinaria , Ovinos , Enfermedades de las Ovejas/parasitologíaRESUMEN
Heat shock protein 90 (HSP90) is a key component of the molecular chaperone complex essential for activating many signalling proteins involved in the development and progression of pathogenic cellular transformation. A Hsp90 gene (BQHsp90) was cloned and characterized from Babesia sp. BQ1 (Lintan), an ovine Babesia isolate belonging to Babesia motasi-like group, by screening a cDNA expression library and performing rapid amplification of cDNA ends. The full-length cDNA of BQHsp90 is 2399 bp with an open reading frame of 2154 bp encoding a predicted 83 kDa polypeptide with 717 amino acid residues. It shows significant homology and similar structural characteristics to Hsp90 of other apicomplex organisms. Phylogenetic analysis, based on the HSP90 amino acid sequences, showed that the Babesia genus is clearly separated from other apicomplexa genera. Five Chinese ovine Babesia isolates were divided into 2 phylogenetic clusters, namely Babesia sp. Xinjiang (previously designated a new species) cluster and B. motasi-like cluster which could be further divided into 2 subclusters (Babesia sp. BQ1 (Lintan)/Babesia sp. Tianzhu and Babesia sp. BQ1 (Ningxian)/Babesia sp. Hebei). Finally, the antigenicity of rBQHSP90 protein from prokaryotic expression was also evaluated using western blot and enzyme-linked immunosorbent assay (ELISA).
Asunto(s)
Babesia/genética , Babesiosis/parasitología , Epítopos , Proteínas HSP90 de Choque Térmico/genética , Enfermedades de las Ovejas/parasitología , Secuencia de Aminoácidos , Animales , Babesia/inmunología , Babesia/aislamiento & purificación , Secuencia de Bases , China , Biblioteca de Genes , Proteínas HSP90 de Choque Térmico/metabolismo , Datos de Secuencia Molecular , Filogenia , Proteínas Protozoarias/genética , Proteínas Protozoarias/metabolismo , Alineación de Secuencia/veterinaria , Análisis de Secuencia de ADN/veterinaria , OvinosRESUMEN
The diversity of Babesia species infecting cervids in parts of central and southern Spain was analyzed by collecting blood from farmed red deer (Cervus elaphus). Babesia sp. was isolated in vitro from two red deer herds in Cádiz and Ciudad Real. The number of Babesia sp. carriers differed between the two herds: 36/77 in Cádiz and 1/35 in Ciudad Real. Hyalomma lusitanicum was the most prevalent tick species identified on the Cádiz farm vegetation and on sampled animals, and is therefore a candidate vector. The molecular characteristics of 21 isolates were determined by complete (8 isolates) or partial (13 isolates) 18S rRNA gene sequencing. The sequences were highly similar (over 99.4% identity) and 6 sequence types were identified at the level of one herd only, demonstrating a rather high genetic diversity. They formed a monophyletic clade, and members of the three main sequence types shared a similar morphology and the same erythrocyte susceptibility pattern. This clade also included Babesia sp. Xinjiang isolated from sheep in China and Babesia sp. identified in giraffe in South Africa, with identities higher than 98.3% and statistically relevant phylogenetic support. None of the biological properties analyzed for both Babesia from red deer and Babesia sp. Xinjiang allowed their differentiation (ability to develop in vitro in erythrocytes from cattle and sheep, as well as in erythrocytes from different cervids, unsuccessful infection of calves). We propose the Babesia isolated from red deer as a new species named B. pecorum. Whether Babesia sp. Xinjiang and the Babesia characterized in South Africa belong to the same species is debated.
Asunto(s)
Babesia/clasificación , Babesia/genética , Babesiosis/parasitología , Ciervos , Crianza de Animales Domésticos , Animales , Babesia/aislamiento & purificación , ADN Protozoario/genética , Datos de Secuencia Molecular , Filogenia , ARN Ribosómico 18S/genética , Análisis de Secuencia de ADN/veterinaria , EspañaRESUMEN
A new gene of Babesia sp. BQ1 (Lintan) (BQP35) was cloned by screening a merozoite cDNA expression library with infected sheep serum and using rapid amplification of cDNA ends (RACE). The nucleotide sequence of the cDNA was 1140bp with an open reading frame (ORF) of 936bp encoding a 35-kDa predicted polypeptide with 311 amino acid residues. Comparison of BQP35 cDNA and genomic DNA sequences showed that BQP35 does not possess an intron. Recombinant BQP35 (rBQP35), expressed in a prokaryotic expression system, showed abnormally slow migration on SDS-PAGE. Gel shifting, amino acid sequence and in silico disorder region prediction indicated that BQP35 protein has characteristics of intrinsically unstructured proteins (IUPs). This is the first description of such proteins in the Babesia genus. BQP35 induced antibodies production as early as one week after Babesia sp. BQ1 (Lintan) infection in sheep. No cross-reaction was observed with sera from sheep infected with other ovine piroplasms dominant in China, except with Babesia sp. Tianzhu. The interest of BQP35 as a diagnostic antigen is discussed.
Asunto(s)
Antígenos de Protozoos/metabolismo , Babesia/metabolismo , Babesiosis/parasitología , Enfermedades de las Ovejas/parasitología , Secuencia de Aminoácidos , Animales , Antígenos de Protozoos/química , Antígenos de Protozoos/genética , Babesia/clasificación , Babesiosis/diagnóstico , Secuencia de Bases , Electroforesis en Gel de Poliacrilamida , Ensayo de Inmunoadsorción Enzimática/veterinaria , Regulación de la Expresión Génica , Biblioteca de Genes , Datos de Secuencia Molecular , Proteínas Protozoarias , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Pruebas Serológicas/veterinaria , Ovinos , Enfermedades de las Ovejas/diagnósticoRESUMEN
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.
Asunto(s)
Antígenos de Protozoos/sangre , Babesia/inmunología , Babesiosis/veterinaria , Enfermedades de los Bovinos/parasitología , Eritrocitos/parasitología , Parasitemia/veterinaria , Animales , Babesiosis/parasitología , Western Blotting/veterinaria , Bovinos , Electroforesis en Gel de Poliacrilamida/veterinaria , Parasitemia/parasitología , Especificidad de la Especie , Factores de TiempoRESUMEN
Buffalo fasciolosis induced by Fasciola gigantica causes important economic losses in tropical areas of Asia. Detection of prepatent infection is essential to control this disease. Classical tools such as coprology, necroscopy or ELISA based on crude extracts from F. gigantica are poorly sensitive or specific. Purified antigens could be used to increase these parameters. Western blot analysis and mass spectrometry of a fraction of F. gigantica excretory-secretory products obtained by gel filtration showed that thioredoxin peroxidase could be a potential antigen for serodiagnosis: it was recognized from the 2nd week after infection, by all buffalo experimentally or naturally infected with F. gigantica but not by healthy animals.
Asunto(s)
Antígenos Helmínticos/aislamiento & purificación , Búfalos/parasitología , Enfermedades de los Bovinos/diagnóstico , Fasciola/aislamiento & purificación , Fascioliasis/veterinaria , Peroxirredoxinas/metabolismo , Animales , Anticuerpos Antihelmínticos/sangre , Antígenos Helmínticos/inmunología , Asia , Western Blotting/métodos , Bovinos , Enfermedades de los Bovinos/inmunología , Enfermedades de los Bovinos/parasitología , Ensayo de Inmunoadsorción Enzimática/métodos , Fasciola/crecimiento & desarrollo , Fascioliasis/diagnóstico , Fascioliasis/inmunología , Proteínas del Helminto/inmunología , Pruebas SerológicasRESUMEN
The Babesia species "BQ1 (Lintan)" is infective to sheep and goats. The species was isolated from Haemaphysalis qinghaiensis collected in the Gannan Tibet Autonomous Region, China in April 2000. In this study, an in vitro culture system was developed for the propagation of Babesia sp. BQ1 (Lintan). Continuous cultivation and 5.0% parasitemia was obtained in vitro in RPMI 1640 medium with sheep red blood cells (RBC) (7.5%) supplemented with Fetal Bovine Serum (FBS) (20%), Amphotericin B (0.5 microg/ml) and Gentamicin (50 microg/ml) in an incubator at 37 degrees C and 6% CO(2) in 24-well and 6-well plates. Parasitemia could attain 10% in 75 cm(2) flasks with the same culture medium but with 2.5% RBC. A clonal line of Babesia sp. BQ1 (Lintan) was screened using the limiting dilution method and designated G7. Growth of Babesia sp. BQ1 (Lintan) in vitro was measured by microtitre-based spectrophotometric method and from parasitemia counts. The generation time was between 20.57 h (based the A(405) of the culture supernatant) and 26.41 h (based on parasitemia). Three French sheep were successfully infected with the culture and the infectivity of the clonal line G7 was determined. Finally, this in vitro culture system was used to compare the susceptibility (capacity to sustain Babesia sp. growth in vitro) of RBC from French sheep (Vendéen breed) and Chinese sheep (Tan mutton breed) for Babesia sp. BQ1 (Lintan) and B. divergens. The lower susceptibility to B. divergens and Babesia sp. BQ1 (Lintan) of RBC from French sheep, compared to Chinese sheep, is discussed.
Asunto(s)
Babesia/crecimiento & desarrollo , Babesiosis/veterinaria , Eritrocitos/parasitología , Parasitemia/veterinaria , Enfermedades de las Ovejas/parasitología , Animales , Babesiosis/genética , Babesiosis/parasitología , ADN Protozoario/química , ADN Protozoario/genética , Predisposición Genética a la Enfermedad , Parasitemia/genética , Parasitemia/parasitología , Reacción en Cadena de la Polimerasa/veterinaria , ARN Ribosómico 18S/química , ARN Ribosómico 18S/genética , Ovinos , Enfermedades de las Ovejas/genéticaRESUMEN
Helminth parasites are of considerable medical and economic importance. Studies of the immune response against helminths are of great interest in understanding interactions between the host immune system and parasites. Effector immune mechanisms against tissue-dwelling helminths and helminths localized in the lumen of organs, and their regulation, are reviewed. Helminth infections are characterized by an association of Th2-like and Treg responses. Worms are able to persist in the host and are mainly responsible for chronic infection despite a strong immune response developed by the parasitized host. Two types of protection against the parasite, namely, premune and partial immunities, have been described. Immune responses against helminths can also participate in pathogenesis. Th2/Treg-like immunomodulation allows the survival of both host and parasite by controlling immunopathologic disorders and parasite persistence. Consequences of the modified Th2-like responses on co-infection, vaccination, and inflammatory diseases are discussed.
Asunto(s)
Helmintiasis/inmunología , Helmintos/inmunología , Animales , Antihelmínticos/uso terapéutico , Helmintiasis/tratamiento farmacológico , Helmintiasis/prevención & control , Interacciones Huésped-Parásitos , Humanos , Modelos Inmunológicos , Vacunas/uso terapéuticoRESUMEN
Ovine babesiosis is an economically important disease induced by tick transmitted haemoparasites throughout the world. In China, several ovine Babesia strains have been isolated from field-collected ticks or sheep blood during the last two decades but little is known about the vector ticks and transmission pattern. Babesia sp. BQ1 (Lintan) is a Babesia strain infective for sheep and goats, isolated from blood of sheep experimentally infested with Haemaphysalis qinghaiensis collected in field. In the present study, we explored the experimental transmission of Babesia sp. BQ1 (Lintan) to sheep by H. qinghaiensis and Haemaphysalis longicornis. Based on the evidence from nested PCR, it suggested that H. qinghaiensis and H. longicornis are the potential vector ticks of Babesia sp. BQ1 (Lintan) and that larvae, nymphs and adults of both tick species were able to transmit Babesia sp. BQ1 (Lintan) to sheep. Parasites could be detected in the blood, by specific nested PCR, for one month post-infestation.
Asunto(s)
Vectores Arácnidos/parasitología , Babesia/patogenicidad , Babesiosis/transmisión , Ixodidae/parasitología , Enfermedades de las Ovejas/transmisión , Animales , Vectores Arácnidos/crecimiento & desarrollo , Babesia/genética , Babesia/aislamiento & purificación , Babesiosis/parasitología , Sangre/parasitología , China , Femenino , Ixodidae/crecimiento & desarrollo , Larva/parasitología , Ninfa/parasitología , Reacción en Cadena de la Polimerasa , Ovinos/parasitología , Enfermedades de las Ovejas/parasitología , Infestaciones por Garrapatas/parasitologíaRESUMEN
Babesia divergens is an intraerythrocytic Apicomplexa and the main agent of bovine babesiosis in Europe. The infection in cattle develops in 2 phases: an acute phase with hemolytic anemia and a chronic phase with asymptomatic persistence of the parasite for several years. The acute phase of B. divergens infection can be studied using the gerbil (Meriones unguiculatus) as a laboratory model but unlike cattle, this animal rapidly eliminates the parasite. An experimental model to study the chronic phase of infection was therefore developed by our laboratory. Spleen-intact sheep, with a potential full immune response, were inoculated with infected red blood cells (iRBC) or with free merozoites, by several routes (intraperitoneal, intravenous or subcutaneously). No clinical signs were ever observed but the installation of a persistent low level infection was shown in sheep with susceptible erythrocytes (able to sustain B. divergens growth in vitro). Neither feature was observed in sheep with non-susceptible erythrocytes. IgG production, involving both IgG1 and IgG2, was mainly directed against the major merozoite surface antigen Bd37, similar to the humoral immune response described in naturally infected cattle. The use of spleen-intact sheep to study the immune response to B. divergens is discussed.
Asunto(s)
Babesiosis/inmunología , Inmunidad Humoral/inmunología , Parasitemia/inmunología , Enfermedades de las Ovejas/inmunología , Enfermedades de las Ovejas/parasitología , Bazo/inmunología , Animales , Anticuerpos Antiprotozoarios/sangre , Antígenos de Protozoos/inmunología , Babesia , Bovinos , Enfermedades de los Bovinos/inmunología , Enfermedades de los Bovinos/parasitología , Modelos Animales de Enfermedad , OvinosRESUMEN
The pathogenicity and morphology of a large Babesia species, Babesia sp. Xinjiang, are described here. The parasite has very low virulence for sheep, and caused no detectable clinical symptoms. Splenectomized sheep infected with the parasite showed mild fever and low parasitemia and would recover gradually. If splenectomized sheep were immuno-suppressed with dexamethasone, the parasitemia could reach 8.5%, and death occurred. A splenectomized calf could not be infected with the Babesia species. Paired parasites were the typical form of the Babesia species in erythrocytes and the average size of a pair of parasites was 2.42 (+/-0.35) microm x 1.06 (+/-0.22) microm. Merozoites were found in the gut, salivary gland, haemolymph, ovary and eggs of female Hyalomma anatolicum anatolicum engorged on sheep infected with the parasites. The results of experimental transmission showed that the larval, nymph and adult stages of H. a. anatolicum could transmit the Babesia species to sheep.
Asunto(s)
Vectores Arácnidos/parasitología , Babesia/clasificación , Babesiosis/veterinaria , Ixodidae/parasitología , Enfermedades de las Ovejas/transmisión , Animales , Babesia/genética , Babesia/patogenicidad , Babesiosis/parasitología , Babesiosis/transmisión , Bovinos , Enfermedades de los Bovinos/parasitología , Enfermedades de los Bovinos/transmisión , Eritrocitos/parasitología , Femenino , Cabras , Hemolinfa/parasitología , Larva/parasitología , Técnicas de Amplificación de Ácido Nucleico/veterinaria , Ninfa/parasitología , Ovario/parasitología , Óvulo/parasitología , Filogenia , Glándulas Salivales/parasitología , Ovinos , Enfermedades de las Ovejas/parasitología , Esplenectomía/veterinaria , VirulenciaRESUMEN
Babesia, the causal agent of babesiosis, are tick-borne apicomplexan protozoa. True babesiae (Babesia genus sensu stricto) are biologically characterized by direct development in erythrocytes and by transovarial transmission in the tick. A large number of true Babesia species have been described in various vertebrate and tick hosts. This review presents the genus then discusses specific adaptations of Babesia spp. to their hosts to achieve efficient transmission. The main adaptations lead to long-lasting interactions which result in the induction of two reservoirs: in the vertebrate host during low long-term parasitemia and throughout the life cycle of the tick host as a result of transovarial and transstadial transmission. The molecular bases of these adaptations in vertebrate hosts are partially known but few of the tick-host interaction mechanisms have been elucidated.
Asunto(s)
Babesia/fisiología , Babesiosis/parasitología , Adaptación Fisiológica , Animales , Babesia/genética , Interacciones Huésped-Parásitos , Garrapatas/parasitología , VertebradosRESUMEN
Susceptibility of sheep erythrocytes to Babesia divergens was investigated in vitro and a high inter-individual variability in their ability to support parasite population development was demonstrated, with some individuals having refractory red blood cells (RBC). As neither changes in growth conditions nor the use of different B. divergens strains influenced the level of susceptibility, the main factor postulated for this variability is the erythrocyte itself. Sheep therefore represent an excellent in vitro model to study the parasite-erythrocyte interaction. In addition, the existence of refractory RBC should help in the identification of the erythrocyte components required for B. divergens development. Experimental infections were carried out on spleen-intact sheep characterized by refractory or fully susceptible erythrocyte types. These differences translated into the successful infection of only those animals with susceptible erythrocytes: infected animals showed no clinical signs, but maintained an asymptomatic persistent infection, as usually observed in the natural bovine host. Sheep therefore represent model organisms that can allow us to study interactions between B. divergens and its vertebrate host at different levels of biological organisation, from the target cell to the intact animal, and represent an experimental infection model of concomitant immunity. Only a low percentage (13%) of the sheep population tested possessed susceptible erythrocytes and the potential role of sheep as a natural host or reservoir of B. divergens is discussed.