Identification of Babesia bigemina infected erythrocyte surface antigens containing epitopes conserved among strains

The presence of previously uncharacterized antigens (new antigens) on the surface of intact erythrocytes infected with three strains of Babesia bigemina from Kenya and one each from Puerto Rico, Mexico, St. Croix, and Texcoco-Mexico was demonstrated by indirect immunofluorescent antibody (IFA) reactions. These antigens were not strain specific because antibodies in bovine immune serum to either the Mexico or Kenya isolates reacted with all seven strains tested. Homologous and heterologous immune serum antibodies bound a maximum of 83% and 55%, respectively, of intact erythrocytes infected with the Kenya-Ngong strain but not uninfected erythrocytes. Both sera caused agglutination of only infected erythrocytes. Antibodies eluted from the surface of glutaraldehyde (0.25%) fixed infected erythrocytes had IFA reaction patterns among strains similar to those of immune sera before elation. Eluted antibodies were used to determine if these antigens were protein and encoded by B. bigemina. Eluted antibodies bound seven parasite-encoded proteins of 240, 220, 66, 62, 58, 52 and 38 kDa in an erythrocyte surfacespecific immunoprecipitation reaction of ³⁵-methionine labelled proteins. It was concluded that the surface of B. bigemina infected erythrocytes had parasite-encoded proteins and that these proteins had surface exposed epitopes that were conserved among the seven strains examined which were from two continents.     

利用BgAMA-1抗原建立吉布森巴贝斯虫的ELISA诊断方法

本研究利用基因重组技术,构建并表达吉布森巴贝斯虫的重组顶膜抗原-1(BgAMA-1),将BgAMA-1作为诊断抗原,建立针对吉布森巴贝斯虫的ELISA诊断方法。结果显示,构建的重组表达质粒得以表达,建立的ELISA方法在血清学诊断中有较好的特异性。     

The first case of locally acquired tick-borne Babesia microti infection in Canada

A child with a complicated medical history that included asplenia acquired an infection with Babesia microti in the summer of 2013 and had not travelled outside of Manitoba. Although the clinical findings were subtle, astute laboratory work helped to reach a preliminary identification of Babesia species, while reference laboratory testing confirmed the diagnosis. Blacklegged ticks (Ixodes scapularis) are known to transmit Borrelia burgdorferi and Anaplasma phagocytophilum in the province; however, the present case represents the first known instance of tick-borne B microti, both in Manitoba and in Canada. The expanding territory of the blacklegged tick increases the relevance of this emerging infection. Clinicians, laboratory medical practitioners and public health officials should be aware of B microti as a potential locally acquired infection in Canada.     

Transverse Myelitis Secondary To Coexistent Lyme Disease And Babesiosis

Abstract

Objective: To describe transverse myelitis secondary to coexistent Lyme disease and babesiosis.

Method: Case report.

Background: A 7 4-year-old man presented with rapid onset of weakness, numbness, and tingling in his legs, with symptoms ascending to his hands and forearms within days. He recalled an insect bite to his scapular area 2 weeks earlier.

Findings: T2-weighted magnetic resonance imaging demonstrated diffuse hyperintensity from T1 through T1 2. Western blot and enzyme-linked immunosorbent assay identified infection with Borrelia burgdorferi, the spirochete responsible for Lyme disease. Giemsa-stained blood smears identified ring forms later recognized by polymerase chain reaction as Babesia microti, the piroplasm responsible for babesiosis. Initial examination revealed C7 motor and T3 sensory complete tetraplegia, with recovery to T 4 paraplegia by 2 months.

Conclusion: The history, physical examination, imaging, and serologic studies were consistent with transverse myelitis related to Lyme disease and babesiosis. The severity and permanence of this patient’s deficits were greater than those reported in the majority of previous cases of transverse myelitis due to Lyme disease alone, suggesting a possible role for coinfection with babesiosis.     

福建省动物宿主感染巴贝虫调查研究

目的了解福建省动物宿主感染巴贝虫状况。方法 2014-2016年本中心在福建各地捕鼠,笼日法捕鼠,采集鼠心脏血,同时采集牛、羊和狗的血液样本,采用PCR扩增巴贝虫18SrRNA基因,感染率的比较采用χ2检验或Fisher’s确切概率法。结果调查共布放鼠笼5 917笼次,捕鼠381只,鼠密度为6.44%。全省鼠类巴贝虫的感染率7.61%。家栖鼠中仅3只感染巴贝虫,感染率为1.68%。野鼠中26只感染巴贝虫,感染率为12.87%。野鼠感染率远高于家鼠,差异存在统计学意义(P0.05)。地区分布看,闽中地区感染率最高,其次为闽东,闽南地区感染率最低,差异存在统计学意义(P0.05)。其他动物,牛的血样未检出巴贝虫,狗和羊的血样中各1只检出巴贝虫,感染率分别为1.79%和0.55%。鼠类的巴贝虫感染率高于其他动物的感染率,差异存在统计学意义(P0.05)。序列分析显示鼠类感染的均为田鼠巴贝虫。而犬中检出的巴贝虫为犬巴贝虫。结论福建省巴贝虫宿主动物中鼠类尤其是野鼠,感染率最高,可能是我省巴贝虫最重要的宿主。     

人感染田鼠巴贝斯虫的实验室诊断一例

目的通过回顾1例人感染巴贝斯虫的实验室资料,以积累经验,提高诊断水平。方法研究红细胞(RBC)、血小板(PLT)直方图,白细胞(WBC)VCS散点图;观察外周血、骨髓涂片中虫体的形态;从患者外周血中提取的DNA核酸用疟原虫、巴贝斯虫种、巴贝斯虫属特异性引物进行聚合酶链反应(PCR)。结果 RBC直方图波峰降低,宽度增加,PLT直方图无异常,WBC VCS散点图非WBC区有颗粒团;外周血、骨髓涂片见大量拟似恶性疟原虫虫体;PCR产物测序结果经BLAST比对,结果显示与巴贝斯虫和田鼠巴贝斯虫18s核糖体DNA序列分别有96%和99%的同源性。结论感染的虫体为田鼠巴贝斯虫。     

Red cell exchange transfusion for babesiosis in Rhode Island

We report four cases of clinically severe tick borne babesiosis treated with chemotherapy and adjunctive red cell exchange (RCE) at two Rhode Island hospitals from 2004 to 2007. All RCE procedures were performed using a Cobe Spectra device and were well tolerated without complications. The volume of allogeneic red cells used in the exchange was determined using the algorithm in the apheresis device with the input variables of preprocedure hematocrit, weight, height, an assumed allogeneic red cell hematocrit of 55 and a desired post procedure hematocrit of 27. The preprocedure level of parasitemia varied between 2.4% and 24% and the postprocedure level of parasitemia between 0.4 and 5.5% with an average overall percent reduction in parasitemia of 74%. Retrospectively, application of a new formula to calculate red cell mass appeared to correlate better with the percent reduction in parasitemia. Previous reports of RCE in babesiosis were reviewed. The reported reduction in parasitemia varied from 50% to >90%. Although a preprocedure level of parasitemia of 10% is sometimes used as a threshold for RCE in clinically severe babesiosis, this threshold does not have a firm empirical basis. No postprocedure desired level of parasitemia is indicated nor the mass of allogeneic red cells needed to achieve such a level. We conclude that current estimates of the dose of allogeneic red cells used in RCE are probably inaccurate, advocate a new formula to estimate this dose and suggest that a 90% reduction in parasitemia should be the minimally desired target of RCE in babesiosis. J. Clin. Apheresis, 2009. © 2009 Wiley‐Liss, Inc.     

Oestrus ovis (Diptera: Oestridae): effects of larval excretory/secretory products on nitric oxide production by murine RAW 264.7 macrophages

Larvae of Oestrus ovis (Insecta: Diptera: Oestridae) are common parasites of nasal and sinus cavities of sheep and goats. Previous studies revealed that crude extracts of larvae modify NO synthesis by ovine monocyte derived macrophages. The aim of this study was to investigate the larval excretory/secretory products effects on nitric oxide production by murine tumour macrophages RAW 264.7. Stimulation of RAW macrophages by excretory/secretory products of the three instars larvae (25 microg/ml) significantly increased nitrite concentrations in culture supernatants compared to negative and positive Escherichia coli lipopolysaccharide control. This effect was time and dose dependent. Nitrite production in culture supernatants was due to induction of isoform NOS-2 because both NG monomethyl L-arginine (100 microM) and dexamethasone (20 microM) inhibited, by 60 and 50%, respectively, nitrite accumulation in culture supernatants. First steps of purification, by ion exchange chromatography, indicated that one protein of 29 kDa was able to induce NO synthesis by macrophages. Further studies are needed for a better characterization of these molecule and to investigate their immunogenicity for a vaccine approach.     

Babesia microti, upstate New York

Five cases of human babesiosis were reported in the Lower Hudson Valley Region of New York State in 2001. An investigation to determine if Babesia microti was present in local Ixodes scapularis ticks yielded 5 positive pools in 123 pools tested, the first detection of B. microti from field-collected I. scapularis in upstate New York.