Prompt laboratory diagnosis in timely containment of a plague outbreak in India

A focal outbreak of pneumonic plague occurred in a hamlet of village Hatkoti, district Shimla, Himachal Pradesh in the first fortnight of February, 2002. A total of 16 cases with 4 deaths were reported. Diagnosis of plague was confirmed by the laboratory in 10 (63%) cases. Y. pestis was isolated from clinical samples of 3 cases and confirmed by bacteriophage lysis. Molecular tests confirmed the presence of Y. pestis specific pla and F1 genes in 4 cases; DNA fingerprinting had identity with the known sequence of plague bacilli. Paired samples from 5 cases showed more than 4 fold rise and 1 case showed more than 4 fold fall in antibodies against F1 antigen of Y. pestis. The present communication emphasises that timely and systematic laboratory investigations give confirmatory diagnosis in shortest possible time which forms the backbone of the outbreak control in a timely fashion and prevents confusion and controversy.     

A 12-case outbreak of pharyngeal plague following the consumption of camel meat, in north-eastern Jordan

Between late January and early February 1997, an outbreak of plague, associated with cervical lymphadenopathy and fever, occurred in the Jordanian village of Azraq ad-Druze, which lies about 50 km west of the border with Saudi Arabia. The 12 cases who presented at hospital were initially assumed to have tularaemia, and all were successfully treated with gentamicin. When, however, their sera were tested for evidence of Yersinia pestis or Francisella tularensis infection (using haemagglutination, enzyme immuno-assays for specific IgM or the F1 antigen of Y. pestis, and micro-agglutination tests), all 12 were found to have anti-Y. pestis IgM. Three dogs shot near the Saudi Arabian border were also found seropositive for antibodies against Y. pestis. Eleven of the 12 patients reported that, 2-4 days before their symptoms appeared, they had eaten the meat cut from the carcass of the same camel, either raw (10 cases) or cooked (one case). All 12 patients were diagnosed as cases of pharyngeal plague (the first cases of plague reported in Jordan for more than 80 years), caused by Y. pestis that most had acquired when they ate raw meat from a camel that was infected with the pathogen.     

云南省野鼠疫源地鼠疫指示动物血清F1抗体流行病学调查

目的 通过对云南省野鼠疫源地指示动物血清鼠疫F1抗体阳性率的调查,探讨鼠疫指示动物在鼠疫监测中的作用,为鼠疫防治和确定疫区范围提供科学依据.方法 按<云南省野鼠鼠疫疫源调查实施方案>,在玉龙县及其周围地区共10个县所属14个乡(镇)的75个自然村,对鼠疫指示动物(犬和猫)进行调查,同时采用5 m布笼野外捕捉活鼠.取指示动物和活鼠血清,间接血凝试验OHA)法检测动物血清中的鼠疫F1抗体.结果 共采集鼠疫指示动物血清2897份,F1抗体阳性血清202份,阳性率为6.76%,阳性血清样品全部来自于玉龙县和古城区.其中犬抗体阳性率为5.73%(162/2825),猫抗体阳性率为24.69%(40/162).猫血清F1抗体阳性率显著高于犬,两者比较差异有统计学意义(X2＝87.32,P＜0.01).活鼠血清未检出F1抗体.阳性率为0(0/2363),与指示动物(6.76%)比较差异有统计学意义(P＜0.01).结论 通过指示动物血清F1抗体调查,可以判定玉龙县,古城区为鼠疫疫源县(区),指示动物血清学监测对鼠疫防治具有非常重要的意义.     

鼠疫FI单克隆抗体致敏红细胞用于反向血凝抑制试验检测鼠疫FI抗体的试验研究

本文介绍了鼠疫FI MCAb致敏红细胞用于反向血凝抑制试验检测鼠疫FI抗体的试验。结果表明,用该法检测95份正常人和8种动物血清,7种非鼠疫菌免疫动物血清,全部阴性;检测9份抗鼠疫强毒株和1份弱毒株血清及1份接种鼠疫菌苗的人血清,全部阳性,滴度比间接血凝试验(IHA)高2~1～2~3。该法可省去另做一排抑制试验的操作程序,较IHA简便、快速,在鼠疫疫源地调查和疫情监测中有良好的应用前景。     

Laboratory studies on Yersinia pestis during the 1991 outbreak of plague in Lushoto, Tanzania.

Thirty-one specimens from patients involved in an outbreak of plague were cultured. Suspicious isolates were presumptively identified by colonial characteristics, simple strains and by API 20E, and confirmed by inoculation into white mice. Antimicrobial susceptibility testing was also done. The isolation rate of Y. pestis was 22.6%. All isolates were uniformly sensitive to tetracycline, streptomycin, sulphadimidine and chloramphenicol; moderately sensitive to erythromycin, and resistant to trimethoprim. Y. pestis was confirmed as a cause of the epidemic and sensitivity of Y. pestis to the four antimicrobial agents used was demonstrated. It is recommended that laboratories in zonal hospitals serving areas with plague foci should be provided with facilities for isolation and preliminary identification of Y. pestis in order to speed up diagnosis of plague outbreaks. Confirmation of the identity, biotyping and antibiotic susceptibility testing should be undertaken in a well established national reference laboratory. This appears to be the first publication on bacteriological investigations of human plague in Tanzania.     

An outbreak of plague in Hlegu, Burma in 1977.

An outbreak of plague occurred in Hlegu Town, Burma in February and March 1977. Altogether 14 bubonic plague cases, with 2 deaths were reported, mostly children under 15 years of age. Twice as many males as females were affected. A retrospective investigation showed that a rat fall took place in the last week of January. Only 9.5% of the rodents which died in the epizootic were found to be infected with Y. pestis; this apparent low infection rate probably resulted from the inclusion in the survey of some dead rats which died of other causes. 14.5% out of 48 trapped rodents were found to be serologically positive. The general flea and cheopis indices were rather high, perhaps because fleas were found to be partially resistant to DDT and also because spraying of insecticide did not effect fleas on the hosts. The cheopis index in Hlegu Town was 1.17, and less than 0.5 in Hlegu suburb (Yankin-Yat) where no epizootic was reported. An active case search revealed 76 suspected plague cases out of which 11 were found to have bubonic plague. A field trial showed that plague vaccination during the outbreak did not result in a rise of detectable antibodies in persons inoculated.     

Pulmonic plague

One hundred years after Yersin discovered Yersinia pestis during the plague epidemic in Hong Kong in 1894, human plague still has not been eliminated. The epidemic in 1994 in India, a country where no cases had been observed since 1996, raised great concern. Plague is an epizootic bacterial infection caused by a Gram negative coccobacillus, Y. pestis, transmitted by the bite of infected fleas. Bubonic plague is the most common form. Other clinical presentations include asymptomatic plague, abortive plague, pharyngeal plague, septicemic plague, meningeal plague, and primary or secondary pneumonic plague which is observed in 5 to 20% of cases. Plague is a highly communicable disease between humans despite antibiotic therapy which has reduced mortality by 80%. The prognosis depends on early diagnosis. Streptomycin and cyclines are the gold standard treatment.     

甘肃省1998年鼠疫防治及疫情分析

１９９８年甘肃省各疫源县鼠疫监测面积达３９１５９５ｈｍ＾２。检验各种动物２８８５只,分离鼠疫菌７株;检验媒介昆虫２２６７组,分离鼠疫菌３株发生人类鼠疫１例,从鼠疫患尸检材料分离鼠疫菌１株。用ＩＨＡ方法检测各种血清１８７９份,阳性４２份;用ＲＩＨＡ法检测各种血清３０７份,阳性１０份。     

胶体金免疫层析法快速检测鼠疫耶尔森菌F1抗体

目的建立检测鼠疫耶尔森菌F1抗体的胶体金标记免疫层析方法。方法胶体金标记纯化鼠疫F1抗原,双抗原夹心法原理制成免疫层析检测试纸条,并对兔、羊、人和黄鼠血清进行检测评价。结果用80份不同动物种属的阴性血清进行检测,未出现非特异性反应,对5份恢复期病人血清、13份免疫兔血清和2份免疫羊血清检测也取得阳性结果,对于8份I HA临界阳性(滴度1∶20)的达乌尔黄鼠血清检出阳性6份。结论建立了可以用于现场快速检测鼠疫F1抗体的胶体金免疫层析方法。     

Hereditary hemochromatosis restores the virulence of plague vaccine strains

Nonpigmented Yersinia pestis (pgm) strains are defective in scavenging host iron and have been used in live-attenuated vaccines to combat plague epidemics. Recently, a Y. pestis pgm strain was isolated from a researcher with hereditary hemochromatosis who died from laboratory-acquired plague. We used hemojuvelin-knockout (Hjv(-/-)) mice to examine whether iron-storage disease restores the virulence defects of nonpigmented Y. pestis. Unlike wild-type mice, Hjv(-/-) mice developed lethal plague when challenged with Y. pestis pgm strains. Immunization of Hjv(-/-) mice with a subunit vaccine that blocks Y. pestis type III secretion generated protection against plague. Thus, individuals with hereditary hemochromatosis may be protected with subunit vaccines but should not be exposed to live-attenuated plague vaccines.     

用4对引物聚合酶链式反应检测鼠疫耶尔森氏菌的实验研究

目的用4对引物聚合酶链式反应(以下简称4-Prim er-PCR)来检验鼠疫耶尔森氏菌,对于探索鼠疫的快速诊断方法将起到推动作用。方法选择不同疫源地的40株鼠疫耶尔森氏菌;目的基因选择于与鼠疫耶尔森氏菌毒力因子有关的FI抗原质粒基因cafI鼠疫杆菌素Ⅰ基因、与色素沉着有关的质粒基因hm s以及染色体基因inv。结果该法所有的鼠疫耶尔森氏菌全部出现4对引物的预期扩增带;该试验在4 h内完成;结论四对引物鼠疫PCR法具有快速、特异、敏感等优点,可以用于鼠疫的快速诊断和流行病学调查。     

贵州省天生桥水电站库区沿岸鼠疫疫源地调查

目的 查明贵州省天生桥水电站库区沿岸鼠疫疫源地主要宿主动物和媒介蚤类，确定疫源地的性质和分布范围，为预防控制鼠疫提供依据。方法 运用现场流行病学调查方法，调查贵州省天生桥水电站库区沿岸7个乡镇36个村寨，采集啮齿动物、蚤类和指示动物标本，检测鼠疫菌、鼠疫F1抗原和F1抗体。结果 该地区啮齿动物有3科12属21种；媒介蚤有5种，黄胸鼠和印鼠客蚤为优势种。在4个乡镇的12个村寨检出鼠疫感染，鼠疫F1抗原阳性率啮齿动物0．89％、蚤类7．41％；鼠疫F1抗体阳性率啮齿动物0．54％、指示动物1．35％；从黄胸鼠和褐家鼠中培养分离鼠疫菌3株。结论 天生桥水电站库区沿岸的鼠疫疫源地具有与黄胸鼠鼠疫疫源地相同的特征，动物鼠疫流行是由于水库蓄水所引起。     

Are carnivores universally good sentinels of plague?

Sylvatic plague, caused by the bacterium Yersinia pestis, is a flea-borne disease that primarily affects rodents but has been detected in over 200 mammal species worldwide. Mammalian carnivores are routinely surveyed as sentinels of local plague activity, since they can present antibodies to Y. pestis infection but show few clinical signs. In Boulder County, Colorado, USA, plague epizootic events are episodic and occur in black-tailed prairie dogs. Enzootic hosts are unidentified as are plague foci. For three years, we systematically sampled carnivores in two distinct habitat types to determine whether carnivores may play a role in maintenance or transmission of Y. pestis and to identify habitats associated with increased plague prevalence. We sampled 83 individuals representing six carnivore species and found only two that had been exposed to Y. pestis. The low overall rate of plague exposure in carnivores suggests that plague may be ephemeral in this study system, and thus we cannot draw any conclusions regarding habitat-associated plague foci or temporal changes in plague activity. Plague epizootics involving prairie dogs were confirmed in this study system during two of the three years of this study, and we therefore suggest that the targeting carnivores to survey for plague may not be appropriate in all ecological systems.     

2010年陕西省定边县鼠疫自然疫源地东方田鼠生态学调查

目的 了解鼠疫疫源地鼠种构成、鼠密度变化情况及带菌率,为鼠疫的防治提供依据.方法 2010年10、11月,按照《全国鼠疫监测方案》要求,在定边县定边镇北园子村北部,采用一日弓形夹法和5m夹线法进行宿主动物监测,并对宿主肝、脾进行鼠疫菌培养鉴定.结果 一日弓形夹法捕鼠112只,平均鼠密度为8.62只/hm2,其中长爪沙鼠100只,东方田鼠5只,达乌尔鼠兔3只,子午沙鼠2只,小家鼠和黑线仓鼠各1只.5m夹线法捕鼠173只,其中小家鼠136只,黑线仓鼠36只,东方田鼠1只.东方田鼠在定边县现行鼠疫疫区鄂尔多斯高原荒漠草原南部边缘地带盐碱滩地中捕获,东方田鼠及其他捕获鼠体内未检出鼠疫菌.结论 首次在陕西省鼠疫疫源地发现东方田鼠,增添了该鼠在陕西省新的地理分布区,东方田鼠在陕西省鼠疫疫源地的流行病学意义有待进一步探讨.     

Plague and tularemia

Human plague is a local or systemic flea-transmitted infection caused by Yersinia pestis. It is maintained in well established enzootic foci among wild rodents. This article discusses the clinical findings in plague, diagnosis, treatment, and prevention of plague, and management of contacts of human plague cases and of exposures to epizootic plague. Tularemia shares many features with plague but is widespread in animal and arthropod vector populations and essentially throughout the United States.     

Endemic human plague in New Mexico: risk factors associated with infection

A retrospective case-control study was conducted to identify risk factors, other than contact with infected animal tissues, for infection caused by Yersinia pestis in non-Indian residents of areas with endemic sylvatic plague in New Mexico. The study group consisted of 16 persons who had bacteriologically confirmed cases of plague in the period 1975-1976 and 45 controls who were matched by age, sex, and location of residence. Participants were questioned about outdoor activities, environmental conditions in and around the home, procedures of pet care, exposure to animals and insects, and medical history. The availability of harborage and food sources for wild rodents as a result of human activity in the immediate home environment was associated with risk of infection. Failure to take steps to control fleas on dogs and cats also appeared to be a possible risk factor. No other significant differences were found between patients and controls. Plague in New Mexico appears to result primarily from entry of the reservoir host into the habitat of the human rather than from entry of the human into the sylvatic habitat of the reservoir host.     

云南省剑川县鼠疫疫源地分离菌株基因组多态性

目的 阐明云南剑川野鼠疫源地鼠疫菌种群的演化及其与云南省其他疫源地菌株之间的遗传进化关系。方法 按不同时间、不同疫点、不同分离源,随机选取24株剑川分离鼠疫菌进行研究;采用差异区段(DFR)、规律成簇的间隔短回文重复序列(CRISPRs)及多位点可变数目串联重复序列分析(MLVA)进行基因组多态性分析;以DFR+CRISPRs聚类分析划分簇,再以MLVA26对簇进行聚类分析。结果 24株剑川菌株中,20株菌聚为一个簇(剑川野鼠鼠疫簇);2017年疫情分离3株菌位于丽江野鼠鼠疫簇,与丽江菌株(2017LZ)存在2个位点的差异(N2577,M23);剩余1株为一个独立株;50年代菌株与其邻近的80年代菌株间位点差异未超过3。结论 剑川原野鼠疫源地的发现时间可往前推至上世纪50年代,同时疫情还波及过家鼠和人群;剑川县境内存在2种类型的野鼠疫源地,其鼠疫防控具有复杂性,应继续加强鼠间鼠疫的动态监测。     

固相放射免疫试验检测鼠疫F1抗体

建立了固相放射免疫试验(SPRIA)检测鼠疫F1抗体的方法。被测抗体经F1抗原两次选择结合,提高了检测特异性。检测人和5种非鼠疫疫区动物血清205份,以及假结核菌等6株非鼠疫菌免疫动物血清,全部阴性。检测鼠疫康复人和接种鼠疫苗的7种动物血清8份,IHA和SPRIA全部阳性,放射免疫沉淀(SPA—RIP)有两种动物为阴性结果;阳性反应GMT、SPRIA比IHA高,比SPA—RIP低。试验表明SPRIA检测鼠疫F1抗体,具有良好的特异性和敏感性,操作简便、快速,可检测各种标本。     

Short report: Serodiagnosis of plague in humans and rats using a rapid test

Serodiagnosis of plague is very useful for its retrospective confirmation and for epidemiologic studies in humans and in rodents, since rats constitute the main natural reservoir of Yersinia pestis. We have developed a rapid test for the detection of IgG antibodies to fraction 1 (F1) based on immunochromatography and protein A to detect both human and rat IgG. When tested with reference human sera (35 positive and 37 negative), this assay showed a sensitivity of 94.3% and a specificity of 89.2%. When Rattus rattus and R. norvegicus reference sera (22 positive and 24 negative) were used, the sensitivity was 100% and the specificity was 91.7%. This simple serodiagnostic tool is of great potential value in the surveillance of plague. As far as we know, this test is the first of its kind designed for diagnosis of both humans and animals.