Setaria digitata in cattle of Thailand identified by sodium dodecyl sulfate polyacrylamide gel electrophoresis.

Adult Thai Setaria worms collected from cattle which were bred, housed and slaughtered in Thailand were morphologically identified as Setaria digitata. Furthermore, in sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) adult Thai S. digitata had the same protein profiles as adult Japanese S. digitata, but did not possess the protein with a molecular size of 69 kDa which was confirmed in adult S. marshalli. In addition, there were no differences in the protein profiles between male and female S. digitata. In point of the distribution pattern of the proteins ranging from 73 to 64 kDa revealed by 2D-PAGE, there were no differences between Thai and Japanese S. digitata, and between male and female worms of the species.     

Cerebrospinal setariosis with Setaria marshalli and Setaria digitata infection in cattle

Setaria digitata and S. marshalli larvae were observed in the cerebrospinal cavity of 2 paralyzed cattle in Taiwan. The 2 affected cattle showed quadriplegia and lumbar paralysis, respectively. At necropsy, which was performed 7 days after the 7-month-old cattle became quadriplegic, three and nineteen S. marshalli larvae as well as two female adult worms were found in the cranial cavity, spinal cavity and peritoneal cavity of the cattle, respectively. Necropsy on the other 8-month-old cattle was also performed 3 days after it showed lumbar paralysis, and ten S. digitata larvae were found in the spinal cavity. In both cattle, many mononuclear inflammatory cells mixed with a few eosinophils were seen accumulated in the connective tissue around the root of the spinal nerves. Infiltration of eosinophils and mononuclear inflammatory cells into the epidura and arachnoidea of the brain were also observed. The major inflammatory cell was lymphocytes, but neutrophils and eosinophils were also present. The number of cells in the cerebrospinal fluid collected initially from the two affected cattle were 105/0.01 ml and 143/ 0.01 ml, respectively. This is the first report of cerebrospinal setariosis in cattle associated with S. marshalli.     

Ocular infection of cattle with Setaria digitata

One 5-month-old female native Korean calf and a 2-year-old female Holstein cow raised in two farms about 4 km apart from each other in Korea, were found to have the left eye opaque, which included motile white worms in the aqueous humor. The parasite removed from the left eye of the calf was identified as Setaria digitata based on both light and electron microscopic features. The ocular infection with S. digitata reported herein may document the first aberrant case in Korean cattle.     

Patent infection with Setaria digitata in goats in Saudi Arabia.

A survey was carried out on Saudi sheep and goats during 1995, at the Veterinary Diagnostic laboratory, Jeddah, to study Setaria infection in small ruminants in Saudi Arabia. Setaria digitata worms were detected in the abdominal cavity of 5 out of 48 goats (10.4%). Sheep were not found to be infected. All infected goats were adults of 2-4 years of age and originating from the Jeddah, Mecca and Al-Leith areas. Four cases were recorded during January-March and one during August. No lesions due to S. digitata were found in the visceral organs and brains of the infected goats. This is the first record of patent infection with S. digitata in goats.     

Comparison of microfilaria concentration method for Setaria digitata infection in cattle and for Dirofilaria immitis infection in dogs

Several peripheral blood microfilaria concentration methods that use Acetone (Acetone test), 2% formalin (modified Knott method), 5% Tween 20 solution, distilled water, 1% or 0.1% SDS were compared for their efficacy in detecting Setaria digitata microfilaria in cattle. The Acetone test was found to be more efficacious than the modified Knott method or the 5% Tween 20 solution test for detecting the S. digitata microfilaria in bovine blood. However, besides the Acetone test, the modified Knott method was also found to be suitable for Dirofilaria immitis microfilaria detection in dogs. SDS and distilled water were found not to be effective as hemolytic agent for the disruption of the red blood cell of both the cattle and dogs. Thus, the Acetone test is recommended for the primary screening of microfilaremia of S. digitata in cattle.     

Differentiation of Setaria digitata and Setaria labiatopapillosa using molecular markers

5S rRNA intergenic regions of Setaria digitata and Setaria labiatopapillosa were PCR amplified with primers designed from the 5S rRNA gene of Brugia malayi. The ladder-like banding patterns obtained for the amplifications were distinctly different for the two species. Four amplified products were cloned into the pBS vector and completely sequenced. DNA clones from two individual samples of S. digitata, Sd4 and Sd6, showed 97% sequence homology to each other. All sequenced clones showed the presence of the spliced leader (SL) RNA gene with a 22 nucleotide spliced leader sequence. The phylogenetic tree constructed using these data and the 5S rRNA intergenic regions of several other filarial nematodes showed the Setaria species sharing a branch with Dirofilaria. RAPD-PCR analyses identified 107 bands of which 86 were polymorphic (80%). A dendrogram constructed for S. digitata and S. labiatopapillosa separated the two species into two distinct clusters. The polymorphic loci identified by the RAPD-PCR analyses can be studied further to develop species-specific probes/PCR primers for the identification of each species.     

Demonstration of vector competence of Culex quinquefasciatus (Diptera: Culicidae) for Setaria digitata

In Taiwan, Setaria digitata infection causes a lumber paralysis in increasing number of cattle. Culex quinquefasciatus is one of the predominant mosquitoes, and it has been suspected that C. quinquefasciatus acts as a vector to Setaria nematodes prevalence but this was not confirmed. C. quinquefasciatus, Aedes albopictus and A. aegypti of various strains were investigated using an artificial infection system to evaluate their vector competence. After blood feeding at day 14, the number of larvae (stage III) per infected mosquito in A. aegypti (Liverpool strain), A. aegypti (Kaohsiung strain), A. aegypti (Tungan strain), C. quinquefasciatus (Taichung strain) and A. albopictus (Taichung strain) was 1.3 +/- 0.1, 1.3 +/- 0.1, 1.4 +/- 0.1, 1.0 +/- 0.0 and 0 +/- 0.0 (mean +/- S.E.M), respectively. The vector efficiency index of A. aegypti (Liverpool) was the highest among mosquitoes whereas A. albopictus showed a complete refractoriness to the infection. In conclusion, C. quinquefasciatus demonstrates its potential competence for serving as a transmission vector of S. digitata. This mosquito might therefore be responsible, at least in part, for the prevalence of cattle lumbar paralysis in Taiwan. This is the first report of C. quinquefasciatu demonstrating its vector competence for S. digitata.     

A sensitive polymerase chain reaction based assay for the detection of Setaria digitata: the causative organism of cerebrospinal nematodiasis in goats, sheep and horses

A sensitive PCR assay for the detection of Setaria digitata has been developed. Two oligonucleotide primers (17 nt) were designed from a previously cloned and characterized tandemly arranged repetitive sequence of Setaria digitata. Using these primers, it was possible to amplify small quantities (100 fg) of S. digitata genomic DNA. A simple procedure, using proteinase K and non-ionic detergent NP 40, was followed to process the host blood samples and mosquitoes harbouring L3 larvae. The sensitivity of the polymerase chain reaction based assay surpasses the microscopic detection and the previously reported oligonucleotide based chemiluminescent detection of microfilariae in infected host blood samples and L3 larvae in mosquitoes.     

辽宁庄河奶山羊“腰麻痹病”病原学及病理形态学研究

5例自然感染“腰麻痹病”奶山羊的病灶均局限在脑脊髓系统,其中1例脊髓腔中发现1条活泼的指状腹腔丝虫幼虫,在另一例脊髓实质病变部发现了与指状腹腔丝虫断面相似的虫体断面.各例病变性质均属虫伤性液化坏死性非化脓性脑脊髓炎变化.由此认为,指状腹腔丝虫幼虫是本病的病原.病灶的超微结构观察表明,病变无特异性,主要呈退行性病理变化:神经元、神经胶质细胞及细胞器呈严重的细胞病变,有髓神经纤维脱髓鞘,无髓神经纤维变性溶解,神经毡形成坏死性空洞及出血等变化.     

牛腹腔丝虫对3种伊蚊的感染试验

用牛腹腔指状丝虫和唇乳突丝虫的微丝蚴感染埃及伊蚊、白纹伊蚊和东乡伊蚊,观察了蚊虫的感染情况及牛腹腔丝虫Ⅲ期蚴的形态。结果,这两种丝虫的微丝蚴在3种伊蚊体内都能发育成熟,各蚊种的感染率不同,埃及伊蚊和白纹伊蚊分别为40%和30%以上,东乡伊蚊近70%;Ⅲ期蚴的表面结构不因蚊种而异。以不同蚊体内发育而成的Ⅲ期蚴感染小鼠,均可致小鼠出现与马、羊脑脊髓丝虫病相似的瘫痪或转圈运动等神经症状。由此认为,埃及伊蚊和白纹伊蚊也可能为脑脊髓丝虫病的传播媒介。     

Experimental infection of laboratory animals and sheep with Gongylonema pulchrum in Japan

Japanese White rabbits, Wistar rats, ddY mice, Suffolk sheep, and a domestic cat were each orally inoculated with 20-140 third-stage larvae (L3) of Gongylonema pulchrum, isolated from naturally infected dung beetles captured in Aomori Prefecture. Worm recovery rates were 40.0-72.0% in rabbits at 7, 14, and 19 weeks post-infection (PI) and 3.3-25.0% in rats at 19 weeks PI. Those in 2 sheep at 7 weeks PI showed 53.6% and 29.3%. No worms were recovered from the mice and the cat. In the susceptible animals, many worms were found in the esophagus, and a few were present in the pharyngeal mucosa, tongue, buccal mucosa, and cardiac portion of the stomach wall. No distinct morphological differences were observed in the worms from rabbits and sheep. These results indicate that rabbits are very suitable experimental definitive hosts for G. pulchrum.     

Morphological and molecular phylogenetical identification of Tricodectes pinguis from Japanese black bears (Ursus thibetanus japonicus) in Aomori Prefecture,Japan

Trichodectes pinguis, referred to commonly as the bear-biting louse, has been reported in several bear species. However, graphical (blurred or coarse) and genetic information on the louse is limited. In this study, we identified T. pinguis collected from Japanese black bears in the Aomori Prefecture, Japan. We confirmed 12S rDNA sequences derived from the collected T. pinguis and performed molecular phylogenetic analysis based on 12S rDNA. The analysis revealed the parasitic louse to be T. pinguis. Interestingly, the body size of T. pinguis found in this study was smaller than the previous recorded body size of them in Japan and Turkey. To better understand the biting louse infesting bears, morphometric and genetic information from other bear hosts needs to be accumulated.     

唇乳突丝虫感染蚴接种非固有宿主动物致发脑脊髓丝虫病研究

用东乡伊蚊叮吮含有唇乳突丝虫微丝蚴的模型动物——小鼠血液,待微丝蚴在蚊体内发育至感染期时,分离出感染坳,皮下多点接种43只昆明小鼠(每只15～200条)、1只山羊及2只绵羊(每只200～300条)和4匹驹(每匹750～1 250条);将指状丝虫接种到20只昆明鼠体内,比较两种虫体的致病性。结果:唇乳突丝虫感染鼠有16只经1～8 d潜伏期发病,呈现瘫痪、昏迷症状后死亡.实验羊和驹经5～21d潜伏期后均呈不同程度的运动和神经症状,于接种虫体后40～140 d扑杀.经病理学观察,3种动物脑脊髓均呈现虫伤性液化坏死灶及非化脓性脑脊髓炎变化,在其中枢神经系统组织切片中发现丝虫虫体断面或钙化碎片,从而证明唇乳突丝虫可人工感染昆明小鼠、羊、驹发生脑脊髓丝虫病,进而提出该虫可以成为马、羊脑脊髓丝虫病的病原之一。指状丝虫感染鼠死亡率高于唇乳突丝虫感染鼠(P<0.01),初步认为唇乳突丝虫致病性较指状丝虫弱。     

Absence of Wolbachia endobacteria in Sri Lankan isolates of the nematode parasite of animals Setaria digitata

Setaria digitata is an animal filarial parasite with natural hosts of cattle and buffaloes that causes mild disease conditions. Infection of non-permissive hosts such as goats, sheep and horses, by this nematode can cause cerebrospinal nematodiasis that leads to lumbar paralysis and the eventual death of the animals and inflicts considerable economic losses on livestock farmers. Wolbachia are obligate mutualistic endosymbionts for some filarial nematodes and are currently being targeted for the control of diseases caused by these parasites. However, little is known about the occurrence of this endosymbiont in the Setariidae family. In this work, worms collected from infected cattle in Sri Lanka were morphologically identified as S. digitata and tested for the presence of Wolbachia by PCR screening using the WSP- and Wolbachia-specific 16S rRNA and multilocus sequence typing primers that were designed to amplify the gatB, coxA, hcpA, ftsZ and fbpA sequences of Wolbachia. The presence of endobacteria in S. digitata was also examined by whole-mount immunofluorescence staining of the parasites and transmission electron microscopic studies. These analyses did not produce evidence of presence of Wolbachia or any other endosymbiotic bacteria in S. digitata, whereas such evidence was found in Brugia malayi, which was used as a positive control in this study.     

Incidence of canine Babesia gibsoni infection and subclinical infection among Tosa dogs in Aomori Prefecture, Japan

To identify the incidence of Babesia gibsoni (B. gibsoni) in Aomori Prefecture, northeastern Japan, dogs with acute B. gibsoni infection were investigated at the Animal Teaching Hospital, Kitasato University, between April 2002 and March 2003. Eighteen dogs with acute B. gibsoni infection were recognized; they were all male dogs of the fighting dog breed Tosa. Their platelet counts were below normal and their packed cell volumes (PCVs) were at various levels. We collected blood samples from 141 Tosa dogs from Aomori Prefecture and used polymerase chain reaction assay to investigate the incidence of subclinical B. gibsoni infection. We also looked into the serological abnormalities associated with thrombocytopenia or anemia in subclinical infection. Forty-one of 87 dogs (47.1%) with histories of dog fighting, and one dog of 54 without a history of dog fighting were positive for B. gibsoni; that is, 42 of 141 dogs (29.8%) showed a positive result. The mean platelet counts of dogs with subclinical infection were significantly lower and levels of anti-platelet IgG were significantly higher than levels for dogs without infection. Anti-erythrocyte membrane IgG levels were significantly higher in dogs with subclinical infections, although mean PCVs were not significantly different. Tosa dogs from Aomori Prefecture, Japan, were highly infected with B. gibsoni subclinically and this pathogen might be successfully transmitted during dog fighting. Dogs with subclinical infections were at risk of chronic thrombocytopenia, which may be due to autoimmune mechanisms.     

Reduction in tick numbers (Haemaphysalis longicornis), mortality and incidence of Theileria sergenti infection in field-grazed calves treated with flumethrin pour-on

The effectiveness of the pour-on formulation of flumethrin was tested on grazing cattle. Flumethrin was applied once a month from April to October from 1990 to 1995 to cattle grazing in the Aso area of Kumamoto Prefecture in Japan. Both the number of ticks in the field and the number of ticks feeding on cattle decreased remarkably in relation to the number of years flumethrin was applied. Ticks in the field were not detected in 1994 and 1995, and ticks feeding on cattle decreased to 4% in 1995. Mortality due to Theileria sergenti infection also decreased significantly after more than 3 years of flumethrin pour-on application, although overall mortality did not change. At the end of the trial the incidence of T. sergenti had decreased to one-fifth of the pretrial value, although total incidence of disease had not changed. These results indicated that multiple-year seasonal application of flumethrin pour-on to grazing cattle effectively decreased the number of ticks and decreased both mortality and incidence of T. sergenti.     

Ocular infection of donkeys (Equus asinus) with <Emphasis Type="Italic">Setaria equina</Emphasis>

Seven donkeys raised in different locations in Egypt were found to have a unilateral eye showing motile white worms in the aqueous humor. The parasites were surgically removed from the anterior chamber of the eye in five out of the seven donkeys, and were cleared, mounted and identified as Setaria equina based on light microscopic features. The ocular infection with S. equina reported herein may be the first reported aberrant cases in the Egyptian animals.