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1.
Background: There is no well-established treatment strategy for Babesia gibsoni infection. A new therapeutic protocol using atovaquone (ATV) and azithromycin (AZM) has been proposed, but there is concern about the possible induction of relapse and the emergence of ATV-resistant variants after treatment.
Objective: To evaluate the clinical use of combination therapy with ATV and AZM as a first-line treatment of clinical B. gibsoni infection in dogs, and to investigate the emergence of ATV-resistant variants.
Animals: Eight B. gibsoni naturally infected dogs showing signs of acute onset of disease.
Methods: Retrospective case study. Eight clinical cases received combination therapy with ATV and AZM at Kagoshima University Veterinary Teaching Hospital during 2007–2008, and their clinical courses and clinicopathological parameters were evaluated. In addition, alterations in the cytochrome b ( CYTb ) gene of B. gibsoni were analyzed by polymerase chain reaction and DNA sequencing techniques.
Results: All of the dogs responded well to the treatment, with rapid improvement in their clinical condition and hematological parameters. However, 5 of the 8 dogs relapsed after treatment. Analysis of the CYTb gene strongly suggested the emergence of ATV-resistant variants after treatment.
Conclusions and Clinical Importance: The combination of ATV and AZM can be used as a first-line treatment for dogs with babesiosis, but relapses occur. Attention should be paid to the possible in vivo selection of drug-resistant variants.  相似文献   

2.
A single-nucleotide polymorphism causing the replacement of methionine with isoleucine (M121I) in cytochrome b of Babesia gibsoni has been reported to reduce the susceptibility to atovaquone (ATV) in B. gibsoni infection. In our previous study, B. gibsoni with M121I was suggested to exist in nature. Thus, further examinations were performed. In total, 105 genomic DNA samples from B. gibsoni-infected dogs were collected from western (98 samples from 15 prefectures) and eastern areas (7 samples from 4 prefectures) in Japan. The M121I variant population was identified using allele-specific real-time PCR: it was then detected in nine samples (8.57%), which was higher than that in the previous study (4.11%). Although there are unclear points, such as the history of ATV usage, careful attention should be given to emerging ATV resistance.  相似文献   

3.
Various combination strategies for treating Babesia gibsoni have been described. However, relapses after administering some combinations of antibabesial drugs and the presence of drug-resistant B. gibsoni still pose significant challenges to veterinarians. To compare the efficacy of a combination of clindamycin, diminazene, and imidocarb (CDI) to that of a combination of atovaquone and azithromycin (AA) for the treatment of B. gibsoni and to correlate drug efficacy with B. gibsoni mutations, 30 client-owned dogs with natural B. gibsoni infections were collected in the study. 17 dogs were treated with AA, and 13 dogs were treated with CDI combination. Hematological parameters were recorded on the day that the dogs were presented for treatment and during treatment. To detect the parasitic DNA, the B. gibsoni 18S rRNA gene was amplified, and to analyze the mutations, the cytochrome b (CYTb) gene was sequenced. The therapy duration for all of the dogs that recovered was 23.3±7.8 days in the AA group and 41.7±12.4 days in the CDI group. Nine of the 17 dogs in the AA group and 11 of the 13 dogs in the CDI group completely recovered. Seven dogs in the AA group and 2 dogs in the CDI group relapsed after treatment. The M121I mutation in the B. gibsoni CYTb gene was detected in all of the samples that were collected from AA-relapsed and AA-nonremission dogs. The dogs in the CDI group exhibited higher recovery rates and lower relapse rates during treatment for B. gibsoni infection. In addition, the detected M121I mutation was associated with AA treatment. The CDI combination is a promising alternative treatment strategy for B. gibsoni.  相似文献   

4.
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5.
The Babesia gibsoni heat shock protein 70 gene (BGHsp70) was cloned by polymerase chain reaction (PCR) and sequenced. The length of the gene was 1938 bp and the predicted polypeptide was 646 amino acids long with a calculated molecular weight of 70,627. The amino acid sequences of BGHsp70 from 17 isolates were identical, though there were six types of polymorphisms among the corresponding nucleotide sequences. There was no intron in the BGHsp70 gene. Phylogenetic analysis of the amino acid sequence of Hsp70 showed that B. gibsoni was most closely related to B. bovis and lies within a phylogenetic cluster with Theileria. These results suggest that Hsp70 was well conserved among intraerythrocytic protozoa.  相似文献   

6.
The present study was conducted to determine the cause of low parasitemia and simultaneous reticulocytosis in canine babesiosis. The parasitemia was significantly decreased in in vitro cultures of Babesia gibsoni by the pretreatment of host canine erythrocytes with lead acetate, which is a specific inhibitor of pyrimidine 5'-nucleotidase subclass I (P5N-I). The serum from dogs chronically infected with B. gibsoni did not decrease the activities of hexokinase, glucose-6-phosphate dehydrogenase or 6-phosphogluconate dehydrogenase in canine reticulocytes, although it was previously reported that this serum had inhibitory effects on both the maturation of reticulocytes and the canine P5N-I and purine-specific 5'-nucleotidase activities. Furthermore, the in vitro multiplication of B. gibsoni was significantly inhibited by pyrimidine nucleotides such as cytidine 5'-monophosphate (5'-CMP), which is preferentially catalyzed by P5N-I and also inhibits the morphological maturation of canine reticulocytes. Purine nucleotides such as inosine 5'-monophosphate (5'-IMP) also had an inhibitory effect on the multiplication of this parasite. These results suggest that nucleotides such as 5'-CMP and 5'-IMP might accumulate in young erythrocytes and/or serum in dogs infected with B. gibsoni as a result of the decreased activity of erythrocyte 5'-nucleotidase, and the accumulation of these nucleotides might inhibit the multiplication of this parasite and simultaneously retard the maturation of reticulocytes. The results obtained from the in vitro examinations in the present study may partially clarify the relationship between low parasitemia and simultaneous reticulocytosis in vivo in canine babesiosis.  相似文献   

7.
A pair of oligonucleotide primers were designed according to the nucleotide sequence of the P18 gene of Babesia gibsoni (B. gibsoni), NRCPD strain, and were used to detect parasite DNA from blood samples of B. gibsoni-infected dogs by polymerase chain reaction (PCR). PCR was specific for B. gibsoni since no amplification was detected with DNA from B. Canis or normal dog leucocytes. PCR was sensitive enough to detect parasite DNA from 2.5 microl of blood samples with a parasitemia of 0.000002%. PCR detected parasite DNA from 2 to 222 days post-infection in sequential blood samples derived from a dog experimentally infected with B. gibsoni. The detection of B. gibsoni DNA by PCR was much earlier than the detection of antibodies to B. gibsoni in blood samples by the indirect fluorescent antibody test (IFAT) or that of the parasite itself in Giemsa-stained thin blood smear film examined by microscopy. In addition, 28 field samples collected from dogs in Kansai area, Japan, were tested for B. gibsoni infection. Nine samples were positive in blood smears, 9 samples were positive by IFAT and 11 samples were positive for B. gibsoni DNA by PCR. The nucleotide sequences of PCR products from all 11 samples found positive by PCR were completely identical to that of the P18 gene of the B. gibsoni, NRCPD strain. These results suggest that PCR provides a useful diagnostic tool for the detection of B. gibsoni infection in dogs.  相似文献   

8.
Canine babesiosis is a tick-borne parasitic disease caused by the intraerythrocytic parasites, Babesia canis and Babesia gibsoni. A lethargic, weak, American Staffordshire Terrier (pit bull) dog, which had regenerative, normocytic, normochromic anemia, was shown by polymerase chain reaction analysis to be infected with B. gibsoni. Transmission electron microscopy of ethylenediamine tetraacetic acid-treated blood disclosed many well-preserved, intraerythrocytic babesia trophozoites. Four morphologic forms of babesia trophozoites are described (small spheres, small rods, irregular forms lacking pseudoinclusions, and large spheres having pseudoinclusions) and are compared with intraerythrocytic forms of B. canis and B. gibsoni described in other light and electron microscopic studies of in vivo and in vitro Babesia infections. This is the first detailed transmission electron microscopic study of canine B. gibsoni-infected red blood cells in North America.  相似文献   

9.
Erythrocyte 5'-nucleotidase is thought to be involved in the maturation of erythrocytes. In the present study, in vitro incubation of canine erythrocytes demonstrated that significant inhibition of 5'-nucleotidase activity occurred in the presence of serum from dogs infected with Babesia gibsoni, when the enzyme was assayed with cytidine 5'-monophosphate (5'-CMP) and inosine 5'-monophosphate (5'-IMP) as substrates. The multiplication of B. gibsoni in in vitro culture also resulted in a significant decrease in the enzyme activity of erythrocytes in the culture. Furthermore, the infected serum and 5'-CMP retarded the maturation of canine reticulocytes in vitro. These results suggested that nucleotides such as 5'-CMP and 5'-IMP might accumulate in young erythrocytes and/or serum in dogs infected with B. gibsoni as a result of decreased activity of erythrocyte 5'-nucleotidase, resulting in the delayed maturation of reticulocytes.  相似文献   

10.
The in vitro growth inhibitory activities of 15 drugs against Babesia gibsoni were evaluated following establishment of a continuous culture isolate (Aomori isolate). The culture was successfully continued in an RPMI-1640 medium supplemented with 20% normal canine serum or fetal bovine serum in a humidified atmosphere containing 5% CO(2) and 5% O(2) at 37 degrees C. We used this isolate to evaluate the growth inhibitory effect of naphthoquinone (atovaquone), aromatic diamidine (diminazene and pentamidine), artemisinin compounds (artesunate and dihydroartemisinin), an iron chelator (deferoxamine), quinoline-containing compounds (quinine and chloroquine), macrolide antibiotics (azithromycin), lyncomycin antibiotics (clindamycin), tetracycline antibiotics (doxycycline and minocycline), imidazole antifungals (clotrimazole and ketoconazole), and a nitroimidazole antiprotozoal (metronidazole). Atovaquone and aromatic diamidine showed the highest activity; they were followed by artesunate compounds with nanomole levels of IC(50). Metronidazole did not exhibit activity against the parasite. Other drugs exhibited intermediate in vitro activities with micromole levels of IC(50). This is the first report to screen drug activities against B. gibsoni in vitro. The results of our study may support further in vitro drug evaluation for the establishment of therapeutic strategies against canine B. gibsoni infections.  相似文献   

11.
Molecular characterization of a Babesia gibsoni isolate from a Spanish dog   总被引：1，自引：0，他引：1  
Babesia gibsoni is a morphologically small Babesia species that infects dogs. Molecular techniques have shown that some small Babesia sp. recently described in canids are not related to the original B. gibsoni and they should be assigned to separate taxons. Although the 18s rRNA gene of true B. gibsoni isolates has been studied in the USA, Asia and Australia, no molecular data on the presence and genetic characteristics of B. gibsoni in Europe are available. Blood collected from a Babesia-symptomatic dog from Spain was used for DNA diagnosis by seminested PCR. DNA amplification was positive and the complete 18s rRNA gene of the dog isolate was sequenced, showing 98% homology with B. gibsoni (isolate Asia 1). Evidence from phylogenetic analysis indicated that: The Spanish isolate unambiguously belongs to the B. gibsoni group. The B. gibsoni complex might be diphyletic. In the absence of genetic data from African isolates of B. gibsoni, Asia seems to be the most likely geographical location of origin.  相似文献   

12.
Babesiosis caused by Babesia gibsoni (Asian genotype) is an emerging disease in dogs in the United States. To date, no drugs have been shown to eliminate B. gibsoni (Asian genotype) infections from dogs. Twenty-two dogs that remained persistently infected with B. gibsoni (Asian genotype) after either imidocarb diproprionate and or diminazine aceturate therapy were identified and randomly and evenly distributed into 2 groups. One group was treated with atovaquone and azithromycin combination therapy, and the other group received a placebo. Eight of 10 dogs in the treatment group had no detectable B. gibsoni (Asian genotype) DNA, as determined by a sensitive and specific polymerase chain reaction (PCR) assay, in any of their posttreatment samples. In contrast, B. gibsoni (Asian genotype) DNA was detectable by PCR in the posttreatment samples from 11 of 11 of the placebo-treated dogs. One dog in the treatment group was excluded from the treatment outcome analysis. This dog had 2 consecutive negative PCR assay results and was euthanized because of ongoing degenerative joint disease prior to completion of the study. No adverse effects of treatment were reported in any dog during the study period. A combination of atovaquone and azithromycin is the 1st described treatment that will either eliminate B. gibsoni (Asian genotype) infections or suppress the parasitemia below the limit of detection in the majority of treated dogs.  相似文献   

13.
Resistance to bovine spongiform encephalopathy (BSE) that is significantly associated with insertion/deletion (indel) polymorphisms at two loci (putative promoter and intron 1) on the prion protein gene (PRNP) in cattle has been well documented. Studies suggest that the insertion alleles are related to BSE resistance. Until recently, BSE has never been reported in water buffaloes (unlike cattle). Previous studies have demonstrated that the PRNP gene in water buffalo consists mostly of insertion alleles at both loci; nevertheless, whether or not water buffaloes are genetically resistant to BSE and the role of indel polymorphisms in their resistance status is not clear. We examined the coding region of PRNP to determine the nucleotide and octapeptide-repeat (octarepeats) variations of Anatolian, Murrah and Murrah × Anatolian (M?×?A) water buffaloes. Three synonymous single nucleotide polymorphisms (SNP) at positions 126, 234, and 285, and a non-synonymous SNP at position 322 (G108S) were detected. Triplet G/A/T base substitutions were observed at position 126 and two additional genotypes, T/A and T/G, at this position were determined. We also found six octarepeats that indicated the presence of the wild-type PRNP6 allele in the coding region. To the best of our knowledge, this is the first report of the T/A and T/G genotypes in water buffaloes.  相似文献   

14.
Hemolytic anemia caused by Babesia gibsoni infection in dogs.   总被引：2，自引：0，他引：2  
Babesia gibsoni caused severe hemolytic anemia in 11 dogs from southern California. The most common clinical signs of B gibsoni infection were lethargy, anorexia, anemia, and thrombocytopenia. Acute infection with B gibsoni may be misdiagnosed as autoimmune hemolytic anemia. Diagnosis was most reliably determined by identification of the intraerythrocytic parasites on Giemsa-stained blood smears. The pathogenicity of B gibsoni, difficulties in diagnosis, the parasite's resistance to treatment with available drugs, and frequent interstate movement of dogs indicate that this disease may be a serious threat to dogs throughout the United States.  相似文献   

15.
The therapeutic efficacy of atovaquone against Babesia gibsoni was examined in three dogs experimentally infected with B. gibsoni isolated from naturally infected dogs in Aomori Prefecture, Japan. Once parasitemia reached 10%, atovaquone was administered orally (30 mg/kg twice daily for 7 days). Within 2 days of atovaquone treatment, the parasite disappeared from blood smears without any clinical side effects. Anemia and thrombocytopenia were significantly improved in all the dogs. However, a polymerase chain reaction assay revealed that a B. gibsoni marker gene was intermittently present in peripheral blood after atovaquone therapy, indicating that the organism had not been eliminated, and parasites reappeared in blood smears 33 days after the last treatment. To investigate the change in sensitivity against atovaquone, an in vitro sensitivity test was performed using peripheral blood obtained from an untreated dog that was infected with the original parasite isolate, and from two of the experimentally infected and atovaquone-treated animals (blood was collected at the time of the post-treatment recurrence of the B. gibsoni infection). Atovaquone was added to the culture medium to final concentrations of 0.1, 1, 10, 100, and 1000 nM. For the untreated parasites, complete growth inhibition occurred at 1000 nM of atovaquone, whereas the recurrent parasites were inhibited by only 39.52 +/- 8.34% and 31.31 +/- 8.14% at this concentration after 48 h of incubation. Thus, the recurring parasites were less sensitive to atovaquone than the untreated originally isolated parasites.  相似文献   

16.
This study reports on the epidemiology of Babesia gibsoni in American Pit Bull Terriers living in a region of western Victoria in southern Australia. Both American Pit Bull Terriers (n = 100) and other dog breeds (n = 51) were screened for B gibsoni using immunofluorescent antibody testing (IFAT) and/or polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP). A questionnaire was also completed by each dog owner, ascertaining the husbandry and habits of the dogs sampled. Fourteen dogs were positive for B gibsoni using IFAT and/or PCR-RFLP and all were American Pit Bull Terriers. Dogs that were male and/or had been bitten by or were biters of other American Pit Bull Terriers were more likely to be B gibsoni positive, thus suggesting that blood-to-blood transmission contributes to the spread of this disease between dogs.  相似文献   

17.
为了初步探索肌细胞生成素(MyoG)基因在鹿科动物上的遗传多态性,试验采集56头甘肃马鹿的血液样品,采用PCR-SSCP和克隆测序的方法对MyoG基因(GenBank登录号：FJ746497)5′UTR部分序列进行了单核苷酸多态性(SNPs)检测及序列变异分析。结果表明：①引物P1的PCR扩增片段存在多态性,经克隆测序分析,在5′UTR -237 bp处存在G→A的转换变异,该位点表现为AA、AB和BB 3种基因型,由A和B 2个等位基因控制;对基因型、等位基因频率及群体遗传多态性分析结果发现,AA基因型频率最高,A基因为优势等位基因,该位点多态信息含量(PIC=0.194)为低度多态(PIC＜0.25);经TFSEARCH 1.3分析软件预测发现,该变异可能减少了1个Sp1转录因子。②引物2的PCR扩增片段检测到1个SNP多态位点(—46 bp,G→A),表现为CC、CD和DD 3种基因型, 基因型频率分布为CC＞CD＞DD,该位点多态信息含量(PIC=0.266)为中度多态(0.25＜PIC＜0.5),但该变异并未引起潜在调控元件及蛋白质结合位点的改变。本研究结果为进一步分析MyoG基因SNPs位点与甘肃马鹿胴体、肉质性状的关联性奠定了基础。  相似文献   

18.
A total of 80 free-roaming dogs on Okinawa Island, Japan, were examined for Babesia infection using the polymerase chain reaction (PCR) and sequence analysis. Of 80 samples, 12 were positive in a Babesia genus-specific PCR. Consequent species-specific PCR for B. canis and B. gibsoni revealed that 5 (6.3%) and 7 (8.8%) dogs were infected with B. canis and B. gibsoni, respectively. Sequence analysis of the PCR products revealed that the 18S rRNA gene sequence of B. canis detected from dogs in Okinawa was very close to B. canis vogeli with sequence similarity of 99.94%.  相似文献   

19.
Serotonin receptor 1B (HTR1B) is one of the 14 different identified serotonin receptors which are involved in the regulation of behaviors such as sleep, fear, aggression, mood, and feeding. The aims of this study were to characterize polymorphisms in the 5' coding and the 3' flanking regions of the bovine HTR1B gene among Chinese Holsteins and to identify the association of HTR1B polymorphisms with milk production performance. SSCP was used to examine the polymorphisms at four loci and the fragments with different SSCP patterns were sequenced. A total of three single nucleotide polymorphisms (SNPs) were detected, among which the 205G>T mutation was found to cause a predicted amino acid change: from Ala to Ser at position 69. The polymorphism of G205T was identified to be associated with milk yield trait. Furthermore, the H1-C genotype was found to be associated with a significant increase in milk yield of 489kg vs. the H1-A genotype (P<0.05).  相似文献   

20.
Babesiosis is a world-wide zoonosis caused by tick-borne hematozoan parasites of the genus Babesia. Canine Babesidae have historically been classified as "large Babesia" (Babesia canis) and "small Babesia" (Babesia gibsoni) based on the size of their intraerythrocytic forms. Genetic sequencing technology using the polymerase chain reaction (PCR) has allowed further subdivision. B. gibsoni has three strains: "Asia", "California" and a recently identified small babesial-like parasite, Theileria annae. This newly recognised piroplasm appears to be hyperendemic in northwest Spain. In order to provide some insight into the situation, all the cases diagnosed in our laboratory (NW of Spain) during 2003 were evaluated. Our study (62 samples) shows the existence of a piroplasm morphologically different from B. canis and similar to B. gibsoni, which is genetically related to T. annae. Severe regenerative anemia and thrombocytopenia are almost constant characteristics of infection with T. annae in dogs. In many cases azotemia is found. Abnormally high serum concentrations of urea and creatinin, together with elevated concentrations of inorganic phosphorus, hypoalbuminemia, hypercholesterolemia, proteinuria, high protein/creatinin and presence of hyaline and granular casts in the microscopic examination of urine sediment suggest a glomerular component to the disease. We conclude that observational research and clinical trials should be conducted in order to improve our understanding of this emerging disease in order to provide some insight into the best therapeutic practices.  相似文献   

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