嘉兴市低疟区疟疾流行病学特点与监测方法探讨

目的分析低疟区疟疾流行特点,探讨低疟区疟疾监测方法。方法对嘉兴市基本消灭疟疾后的疟疾监测结果做发热病人血检情况,疟疾病例分类、地区分布、性别与年龄分布、发病时间分布,发病率与感染来源,疫点周围人群调查及病例治疗后复查血检情况,媒介按蚊等回顾性调查研究。结果嘉兴市15年累计发热病人血检阳性率24.25/万(302/124529),均为间日疟。其中:初诊为疟疾和疑似疟疾(简称二热病人)者血检阳性率60.29%(290/481),占总阳性数96.03%(290/302);感冒和发热原因不明者血检阳性率仅为0.97/万(12/124048),占总阳性数3.97%(12/302)。病人发病分布散在,本市户籍人口占25.50%(77/302),年均发病率0.23/10万,外来流动人口占74.50%(225/302)。以高疟区青壮年打工者为主要发病者;以5~10月份为发病高峰期;以中华按蚊为惟一媒介;无二代病例发生。结论嘉兴市疟疾发病率低,疫情稳定。以输入性病例为主的呈点状分布的流行特点。因此,疟疾监测在流动人口较多的低疟区,且以中华按蚊为惟一媒介,对当地人群可以采用二热病人、对流动人口采用四热病人的监测方案。     

低疟区疟疾病例侦查的成本效果分析

１９９５～１９９６年在湖北省的江陵、仙桃２县市进行低疟区简化病例侦查方法的研究。结果显示：每个发热病人的血检费用为１７８元，以二热病人为血检对象的简化病例侦查方案，原虫检出率为９４５％，一次血检检出的阳性人数占总阳性人数的９５３８％，检出每个阳性病例的费用为１８８６元，而以四热病人为血检对象则费用要增加１８０倍，且两种病例侦查方案在降低疟疾发病方面无显著性的差异，同样可以取得较好的防治效果。从流行病学和卫生经济学综合评价，在以中华按蚊为唯一媒介的低疟区，以二热病人为血检对象的病例侦查方案，大幅度减少了血检数量，提高了措施的针对性，可以巩固疟疾防治成果，节省大量的人力、物力和财力，是经济有效，切实可行的优选方案。     

灭疟后期地区提高血检效率的可能途径分析

目前,我国原疟区中的大部分地区已处于灭疟后期,疟疾的流行学特点发生了重大变化,原来的大规模群众运动及全民服药措施已不适应形势发展的需要。自70年代末期开始在全国范围内逐步加强发热病人的疟疾血检工作,有效地加强了传染源的检索。现在所采用的策略主要是病例侦查和根治病人;其中病例侦查以常规血检“四热”病人(即:临床初诊为疟疾,疑似疟疾,感冒,不明原因热病人)为主。虽然血检是一种诊断疟疾最可靠的方法,已被全国各地疟防机构和基层卫生保健机构广泛应用,但是随着疟疾发病率的下降,发热病人血检阳性率也在下降,导致血检率的低下。本文首先回顾了疟疾病例检测方法的演变过程,重点评述了目前血检标准的效率低下问题;然后分析与讨论了提高血检效率的可能途径,最后提出建议,以期为管理者和疟防专家们提供决策依据,指导今后发热病人的疟疾血检工作。     

1999～2003年四川省疟疾监测分析

目的了解四川省疟疾流行现状,为制定新的疟疾防治措施提供科学依据.方法根据我省疟疾监测实施方案,采用疟疾防治中的常规技术和方法.结果四川省和各监测点的疟疾均呈逐年下降趋势;近2年血检确认的病例,已达到上报疫情数的90%以上,而且"二热"(初诊疟疾、疑似疟疾)血检阳性病人已占全部血检阳性病人的90%以上;按蚊密度人房中变化不大,牛房中按蚊密度呈逐年下降趋势.结论应进一步完善各项防治监测措施,抓好现症病人的治疗,提高疟防队伍的业务素质,强化发热病人的血检疟原虫工作,继续加强流动人口的疟疾管理和疫情报告制度.     

1999～2003年四川省疟疾监测分析

目的：了解我省疟疾流行现状，为制定新的疟疾防治措施提供科学依据。方法：根据我省疟疾监测实施方案，采用疟疾防治中的常规技术和方法。结果：四川省和各监测点的疟疾均呈逐年下降趋势；近2年血检确认的病例，已达到上报疫情数的90％以上，而且“二热”(初诊疟疾、疑似疟疾)血检阳性病人已占全部血检阳性病人的90％以上；按蚊密度人房变化不大，牛房按蚊密度呈逐年下降趋势。结论：该省应进一步完善各项防治监测措施，抓好现症病人的治疗，提高疟防队伍的业务素质，强化发热病人的血检疟原虫工作，继续加强流动人口的疟疾管理和疫情报告制度。     

1例输入性恶性疟死亡病例的流行病学调查

目的分析高县首例输入性恶性疟病例的流行病学特征,为制定高县输入性恶性疟防控措施提供科学依据。方法对病例进行现场流行病学调查,以患者住地为中心直径500 m开展疫点处置。结果疫情报告1例输入性恶性疟病例,死亡1例,病程14 d。疫点内监测49人,未发现有发热、寒颤等症状病人,无二代病例发生。室内采用氯氰菊酯(20 mg/m2)杀虫剂灭蚊,处理面积13 500 m2,排查疟区返乡人员27名,无异常,1-7月开展三热病人(凝似疟疾、感冒、不明原因)血检监测176例均为阴性,开展疟防知识健康宣传。结论应加强流动人口的管理和输入性疟疾的防控,进一步规范门诊发热病人疟原虫血检监测和健康教育力度,早日实现消除疟疾的目标。     

岱山县丝虫病、疟疾基本消灭后的监测与防治

[目的]反映岱山县丝虫病、疟疾基本消灭后防治与监测结果，并对灭疟后期监测方法进行探讨。[方法]投放“海酱油”疗法及复查治原阳性患者，以净化丝虫病传染源，进行人群及蚊媒监测，以进一步发现微丝螺阳性者，疟疾通过监测提出重点做好流动人口与门诊“三热”病人血检，是低疟区做好疟疾监测工作关键。[结果]丝虫病通过监测，全县仅在1985年发现2例微丝蚴阳性者，以后进行消灭丝虫病自行考核审评及省市复核审评，确认我县已达到消灭丝虫病标准。疟疾通过监测及时检出输入病例。[结论]今后应继续抓好“两病”监测以巩固和发展消灭丝虫病及灭疟成果。     

2006-2013年江陵县疟疾监测结果分析

目的了解江陵县疟疾发病情况、传疟媒介种类、密度和季节变化,为控制和消除疟疾提供依据。方法开展疟疾病原学和媒介监测,收集整理2006-2013年疟疾监测资料,进行统计与分析。结果 2006-2013年共发现疟疾病例13例,年均发病率0.42/10万,其中3例为输入性疟疾。血检"三热"病人33 333例,血检率0.87%~1.44%,平均1.08%;疟原虫阳性率0.24‰。680名小学生疟疾IFA检测均为阴性。传疟媒介为中华按蚊,叮人率2.26~53.83只/人·夜,传疟能量0.756~10.770。结论江陵县连续3年无本地疟疾病例,已达到消除目标。应加强输入性疟疾监测,根治传染源,控制疫点媒介。     

常州市1990~1999年疟疾监测资料分析

经多年的大规模防治,常州地区近１０年来疟疾发病率已降至１／１０万左右。常规的疟疾监测方法,即疟原虫镜检,其阳性检出率仅为０．０４％左右。为此,可以认为血检对象应从“三热”病人转移到“二热”病人为主。此外,输入性疟疾病例占总发病数的４０．５３％,流动人口的疟防工作不容忽视。     

闽东中华按蚊区域灭疟后期疟疾监测管理

[目的]探讨疟疾传播基本阻断后监测管理措施.[方法]对本地居民“两热”病人、流动人群“三热”病人血检疟原虫,确诊后个案调查、正规治疗和跟踪观察.[结果]流动人群原虫率为3.23%,本地居民为零,追踪观察35例输入性病例全部转阴.[结论]近5年监测显示未发现当地原发和输入性疟疾继发病例,证实了疟防成果巩固.采取“两热”病人和“三热”病人的监测方法,简便可行.提示今后应将往返于高疟区的民工作为重点监测对象.     

微小按蚊分布区灭疟后期疟疾流行病学特点和监测方法研究

目的 探讨广东省微小按蚊分布区灭疟后期流行病学特点和简化疟疾监测方法的可行性。方法 于1998－2000年选择微小按蚊分布区并已经省考核验收达到基本消灭疟疾标准，每年疟疾年发病率相对稳定的开平，台山，高州和怀集4个县（市）为试验区，实行只是“三热”患血检，疫点不处理的简化监测措施，并对监测结果进行成本－效益分析。结果 经过3年的简化监测措施，4个试点县（市）共血检“三热”患47347例次，检出疟原虫阳性174例，且疟疾年发病率继续下降，2000年均降至1／10万或以下，输入病例减少，没有暴发流行点出现，所有病例均呈散发性，病例之间不存在继发关系。99．43％疟疾患都是在临床初诊为疟疾和疑似疟疾中发现，其中初诊是疟疾可发现73．56％病例；初诊是疑似疟疾可发现25．86％病例；只有1例是在初诊为不明原因发热患中发现。成本效益分析显示，若实行“二热”患血检，则每发现1例疟疾患可节省血检费用1777．82元。结论 建议在微小按蚊分布区灭疟后期，疟疾监测可实行“三热”患血检，并把“二热”血检作为重点中的重点；只处理现症患，不处理疫点。     

Attributable fraction estimates and case definitions for malaria in endemic

Asymptomatic carriage of malaria parasites occurs frequently in endemic areas and the detection of parasites in a blood film from a febrile individual does not necessarily indicate clinical malaria. In areas of low and moderate endemicity the parasite prevalence in fever cases can be compared with that in community controls to estimate the fraction of cases which are attributable to malaria. In areas of very high transmission such estimates of the attributable fraction may be imprecise because very few individuals are without parasites. Furthermore, non-malarial fevers appear to suppress low levels of parasitaemia resulting in biased estimates of the attributable fraction. Alternative estimation techniques were therefore explored using data collected during 1989-1991 from a highly endemic area of Tanzania, where over 80 per cent of young children are parasitaemic. Logistic regression methods which model fever risk as a continuous function of parasite density give more precise estimates than simple analyses of parasite prevalence and overcome problems of bias caused by the effects of non-malarial fevers. Such models can be used to estimate the probability that any individual episode is malaria-attributable and can be extended to allow for covariates. A case definition for symptomatic malaria that is used widely in endemic areas requires fever together with a parasite density above a specific cutoff. The choice of a cutoff value can be assisted by using the probabilities derived from the logistic model to estimate the sensitivity and specificity of the case definition.     

Aetiologic factors and clinical features associated with thrombocytopenia in Cameroonese adults: the importance of Plasmodium falciparum malaria

In order to determine the main aetiologies associated with thrombocytopenia in a hospital setting of Cameroon, 180 adults with platelet counts <100x10(9)/L were examined and screened for a full blood count, thick and thin blood films, basic coagulation tests (activated partial thromboplastine time, a one-stage Quick's prothrombin time and a bleeding time), an HIV screening test as well as a bone marrow aspirate using standard methods. Other tests were selectively done as dictated by the suspected diagnosis. The major clinical findings among 180 cases included fever >37.5 C (53.9%), splenomegaly (45.6%) and haemorrhage (30.6%). The main laboratory findings were anaemia (defined as haemoglobin (Hb) <11g/dL) in 80.6% of cases and a positive thick blood film (all confirmed to be P. falciparum) in 30.6% of cases. Out of the 18 different aetiologies associated with a low platelet count in the group studied, malaria appears as the unique cause in 22.2% of cases. Petechial bleeding, bruising and epistaxis were the major forms of bleeding involved (69.1%, 27.3%, and 23.6% respectively). However, only 3 cases diagnosed with malaria showed any form of bleeding (mean malaria parasite densities >15,000/muL of blood in each case). No other haemostatic abnormalities were observed. It may be cost-effective for patients with low platelet counts in malarial regions to be systematically screened for malaria parasites.     

2001-2007年墨江县实施疟疾防治效果分析

[目的]了解墨江县疟疾流行状况,为制定预防措施提供决策依据,最终达到基本消灭疟疾标准。[方法]对墨江县2001-2007年的疟疾发病监测资料进行分析。[结果]墨江县2001～2007年累计报告疟疾病人484例,按照累积人口2465916人计算,年均发病率为19．03／10万,无死亡病例;发病最多是2001年,全县350312人,发病172例,发病率为49．1／10万;发病最少是2007年,全县356098人,发病15例,发病率为4．21／10万。不同年份间发病率的差异有统计学意义（P〈0．01）。全县18个乡镇均有发病,平均发病率最高的是龙坝乡82．25／10万,最低是龙潭乡,发病率为2．2／10万,不同地区间发病率的差异有统计学意义（P〈0．01）。传播媒介以微小按蚊为主。2001-2007年合计常住人口四热病人血检76787人次,阳性率为0．45％,流动人口血检2316人次,阳性率为12．44％。[结论]墨江县疟疾发病率逐年下降至2004年已达到部颁提出的基本消灭疟疾标准,疟疾流行明显得到遏制,当地疫情稳定,防制措施得当。     

A review of the malaria situation in Zimbabwe with special reference to the period 1972-1981

Information on the prevalence, incidence, and geographical distribution of malaria in Zimbabwe is reviewed. Malaria control operations carried out during the last 30 years are briefly described together with available information of their impact on malaria. From 1972 to 1981, 51,962 positive blood slides were submitted to Blair Research Laboratory from health institutions, of which 97.8% were Plasmodium falciparum, 1.8% P. malariae and 0.3% P. ovale. Blood slide surveys undertaken from 1969 to 1981 during which time 156,194 slides were examined showed P. falciparum to constitute 92.5% of malaria infections, P. malariae 8.3% and P. ovale 0.7%. The data from active and passive case finding are used to describe the seasonal and geographical pattern of malaria in Zimbabwe. The seasonal peak of transmission occurs from February to May each year with very low transmission from July to October. Endemicity of malaria is shown to be markedly influenced by altitude varying from hyperendemic in the low altitude areas to hypoendemic or absent on the central watershed.     

Cost of malaria control in China: Henan's consolidation programme from community and government perspectives

OBJECTIVE: To assist with strategic planning for the eradication of malaria in Henan Province, China, which reached the consolidation phase of malaria control in 1992, when only 318 malaria cases were reported. METHODS: We conducted a prospective two-year study of the costs for Henan's malaria control programme. We used a cost model that could also be applied to other malaria programmes in mainland China, and analysed the cost of the three components of Henan's malaria programme: suspected malaria case management, vector surveillance, and population blood surveys. Primary cost data were collected from the government, and data on suspected malaria patients were collected in two malaria counties (population 2 093 100). We enlisted the help of 260 village doctors in six townships or former communes (population 247 762), and studied all 12 325 reported cases of suspected malaria in their catchment areas in 1994 and 1995. FINDINGS: The average annual government investment in malaria control was estimated to be US$ 111 516 (case-management 59%; active blood surveys 25%; vector surveillance 12%; and contingencies and special projects 4%). The average cost (direct and indirect) for patients seeking treatment for suspected malaria was US$ 3.48, equivalent to 10 days' income for rural residents. Each suspected malaria case cost the government an average of US$ 0.78. CONCLUSION: Further cuts in government funding will increase future costs when epidemic malaria returns; investment in malaria control should therefore continue at least at current levels of US$ 0.03 per person at risk.     

靖江市2002～2004年疟疾监测结果分析

[目的]为了解灭疟后期疟疾疫情情况。[方法]对2002～2004年靖江市疟疾监测结果进行分析。[结果]2002～2004年疟疾本地感染25例,流动人口感染10例,其中间日疟34例,恶性疟1例;“三热”病人血检7472人,血检疟原虫阳性6人。IFA检测1200人,阳性33人。[结论]本地和流动人口每年均有疟疾发生,防治疟疾工作应本地和流动人口并重。     

Malaria outbreak in a malaria-free region in Oman 1998: unknown impact of civil war in Africa

Beginning in April 1998, the surveillance system in Dhofar region, Oman, detected malaria cases among individuals who had no risk factors for the acquisition of malaria. An investigation was conducted to describe the outbreak and to identify its possible causes. A malaria case was defined as an unexplained fever (>38 degrees C) in a resident of the Dhofar region from April to September 1998. The investigation consisted of enhanced passive case detection, active case finding through contact screening, mass blood survey and school survey. Also an entomological survey was conducted and meteorological data was reviewed. Over a period of seven months, 1279 patients with fever were examined for malaria parasites. Sixty-five cases were positive; 60 (92%) males and 5 (8%) females. Cases occurred in all age groups (range: 2-63 years, median 25 years). Most cases were among illegal Somali immigrants (28, 43%) followed by Omanis (20, 31%). Out of the 2323 slides collected from the community and 2487 from school children, 21 slides were positive. All of them were from illegal immigrants. The entomological survey detected three vectors, previously found in the region: A. d'thali, A. sergenti and A. stephensi. Although the region is classified as a malaria-free region, it has the potential for malaria introduction. This outbreak most likely occurred due to the influx of hundreds of illegal Somali immigrants due to the civil war into the Dhofar region, providing a sufficient number of gametocyte carriers for local anopheline mosquitoes to feed on.     

Reliable assessment of malaria prevalence through village clinics

In 4 villages in the Pakistani Punjab, clinic surveys (CS) provided similar results on total malaria and malaria species prevalence as those from mass surveys (MS)--and at a fraction of the effort. This was true at 3 different levels of malaria transmission. Both methods requiring blood films from all interviewed subjects are believed to be superior to the classical active (ACD) and passive (PCD) case detection methods which sample only patients with a history of recent fever. These latter methods would not detect the large population of oligo- and asymptomatic parasitaemic subjects in the semi-immune population of malaria endemic areas.