闽北地区间日疟原虫对氯喹敏感性的调查

<正> 间日疟原虫对氯喹尚无抗性的征象,但只用氯喹治疗或氯喹加伯喹治疗间日疟原虫病人的复发率各 地报道不一。巴布新几内亚的溪桑株间日疟和一些泰国株间日疟已需用高于常用量的伯喹治疗。故于疟疾流行季节对闽北的建阳、崇安县进行调查及测试。     

中国中部疟疾流行区间日疟原虫对氯喹敏感性的体外检测

目的检测我国间日疟原虫对氯喹的敏感性。方法采用新建立的间日疟原虫药物敏感性体外微量测定技术,对中国中部间日疟流行区门诊确诊的间日疟病例进行药物敏感性测定。结果在完成药物测定的24例间日疟病例中,间日疟原虫对氯喹的IC50几何均数为63.23nmol/L,95%可信区间为26.23~152.40nmol/L,其中至少有6例显示对氯喹产生了抗性。结论在中国中部间日疟流行地区可能已出现间日疟原虫抗氯喹株。     

间日疟原虫抗药性研究进展

疟疾作为一种致死性很高的全球性寄生虫病,一直被全世界所关注,疟疾的控制也被列入全球三大公共卫生问题之一。由于疟疾抗药性的流行和蔓延,尤其是间日疟抗性的快速传播,使得疟原虫抗性的检测、预测以及新药的研发成为当前研究重点。针对这一系列问题,本文对当前间日疟抗药性检测方法、分子机理以及热点抗间日疟药物做一综述。     

泰国的伯氨喹耐药性间日疟

伯氨喹是能杀灭间日疟原虫肝内休眠体、预防复发从而根治间日疟的唯一药物。在泰国,间日疟原虫引起的感染约占疟疾的50％;在经标准氯喹、伯氨喹合并治疗过的病例中,原虫血症复现率高达18％。本文根据曼谷热带病医院间日疟住院病例资料分析了泰国间日疟原虫对伯氨喹的耐药情况。     

间日疟对氯喹不敏感2例报告

间日疟对氯喹不敏感２例报告广西玉林地区卫生防疫站（５３７０００）卢耀娟，梁炯明氯喹自问世以来，一直是治疗疟疾的首选药。但近年来，已发现不少地区的恶性疟对氯喹产生了不同程度的抗性。作者在近年的疟疾防治中，发现某些间日疟患者用氯喹治疗效果不佳，报告２例如...     

疟原虫氯喹抗生性和免疫的关系

比较疟原虫的生物学特征,不难发现氯喹敏感株和抗性株存在很大差别:疟原虫在获得氯喹抗性的同时常伴有配子体的重新出现或配子体血症增加〔1〕;另外在疟色素形成、致病性以及免疫性方面也明显不同。典型的代表是Peters筛选和培育出的伯氏疟原虫氯喹敏感株(N株)和抗性株(RC株)〔1～3〕。虽然目前尚无直接证据肯定氯喹抗性的产生会影响疟疾免疫,但是在恶性疟原虫7号染色体氯喹抗性相关基因附近存在一个巨大的与疟原虫粘附和抗原变异有关的var基因簇的发现〔4,5〕的确引出这样一个问题:疟原虫的氯喹抗性与疟原虫抗原性改变是否存在某种关联?…     

印度加尔各答和奥里萨地区的间日疟原虫氯喹敏感性调查

自从 1 989年在巴布亚新几内亚地区发现间日疟原虫氯喹耐药性以来 ,在西南太平洋地区、印尼亦相继有报道。 1 995年印度也发现了氯喹耐药性间日疟病例。近十年来 ,印度卫生部门提倡对轻症、无并发症的疟疾患者都使用氯喹治疗 ,致使医生在处理发热患者时未经必要的辅助检查就常规用氯喹 ,这就使得印度部分地区恶性疟原虫对氯喹耐药性十分严重。Nandy等认为 1 995年在印度孟买报道的两例氯喹耐药性间日疟病例尚不确定 ,两个病例在氯喹治疗的第 3天都已有 6 8%～ 78%的疟原虫被清除 ,其中有一例在第 3天改用磺胺多辛 乙胺嘧啶进行治疗。由于…     

用周效磺胺-乙氨嘧啶和单用乙胺嘧啶治疗间日疟

在恶性疟原虫对氯喹产生抗性的地区普遍使用磺胺-乙胺嘧啶合剂(Fansidar)治疗疟疾。经过多年使用后,这种合剂对恶性疟无性体仍然有良好的效果,但一般不推荐用于间日疟的治疗。近几年来,泰国间日疟发病率有明显的增加,而恶性疟感染率仍无变化,其原因可能与使用上述合剂进行治疗有关,因此进行了此项研究。     

实用寄生虫病杂志2001年第9卷文题中英文索引

疟疾套式 PCR扩增特定 SSU r RNA基因片断检测四川疟原虫感染的研究 ( 1 ) :4PCR检测 Pf6 0 .1基因诊断恶性疟实验方法研究 ( 1 ) :8疟史访问在疟疾监测中的作用初探 ( 1 ) :2 1扬中市 1 972 -1 999年疟疾疫情消长及防治效果评价( 1 ) :4 3云南省恶性疟原虫多药抗性基因Asn86 Tyr多态性调查 ( 2 ) :5 2薄层色谱法检测恶性疟原虫乳酸脱氢酶的研究 ( 2 ) :6 5应用 CSP基因型简捷 PCR鉴定法对间日疟原虫分型的初步评价 ( 2 ) :6 7间日疟原虫对氯喹敏感性的体内监测 ( 2 ) :741例输入性恶性疟误诊报告 ( 2 ) :78疟疾病例侦察中血检对象…     

佛山7例输入性疟疾临床分析

目的观察输入性疟疾患者的临床表现和探讨治疗方法。方法联合应用氯喹和伯氨喹治疗间日疟疟疾患者,应用蒿甲醚治疗恶性疟疟疾患者。结果间日疟疟疾对氯喹仍敏感,恶性疟疟疾用氯喹治疗后短期内均复发。结论对于输入性恶性疟疟疾患者,应考虑出现耐氯喹病例,尽早应用蒿甲醚进行治疗。     

Therapeutic responses to antimalarial and antibacterial drugs in vivax malaria

Plasmodium vivax is the most prevalent malaria infection and is an important cause of morbidity in Central and South America and Asia. P. vivax is generally sensitive to the common antimalarial drugs but high level resistance to chloroquine and/or pyrimethamine has been documented in some geographic locations. In the studies reviewed here, the therapeutic responses to antimalarial and antibacterial drugs in vivax malaria have been assessed in the Bangkok Hospital for Tropical Diseases. The evaluated drugs consisted of the eight most widely used antimalarial drugs and anti-bacterial drugs that possess antimalarial activities (tetracycline, doxycycline, clindamycin or azithromycin). The activities of these drugs in descending order of parasite clearance times were artesunate, artemether, chloroquine, mefloquine, quinine, halofantrine, primaquine, followed by the antibacterial drugs and lastly sulfadoxine-pyrimethamine. Clinical responses to sulfadoxine-pyrimethamine were also poor with evidence of high grade resistance in 42% of the patients. Of the four antibacterial drugs, clindamycin was more effective than azithromycin and can be an alternative to the tetracyclines. Except for chloroquine and mefloquine which have long plasma half lives and may therefore suppress first relapses, the cumulative cure rates for the short acting antimalarial drugs were similar. Double infection with Plasmodium falciparum was common and usually manifested 3-4 weeks following clearance of vivax malaria. The prevalence of cryptic falciparum malaria was 8-15% and was higher in patients treated with less potent antimalarial drugs. Follow-up studies have revealed that the relapse time in Thai patients with vivax malaria is on average only 3 weeks, but can be suppressed by the slowly eliminated antimalarial drugs such as chloroquine and mefloquine. For accurate comparison of relapse/recrudescence rates in vivax malaria, at least 2 month's follow-up is required. It can be concluded that in malarious areas of Thailand, double infection with P. falciparum and P. vivax is common affecting at least 25% of the patients and usually manifests as sequential illnesses. P. vivax in Thailand is sensitive to chloroquine but has acquired high grade resistance to sulfadoxine-pyrimethamine.     

Pyrimethamine and WR99210 exert opposing selection on dihydrofolate reductase from Plasmodium vivax

Plasmodium vivax is a major public health problem in Asia and South and Central America where it is most prevalent. Until very recently, the parasite has been effectively treated with chloroquine, but resistance to this drug has now been reported in several areas. Affordable alternative treatments for vivax malaria are urgently needed. Pyrimethamine-sulfadoxine is an inhibitor of dihydrofolate reductase (DHFR) that has been widely used to treat chloroquine-resistant Plasmodium falciparum malaria. DHFR inhibitors have not been considered for treatment of vivax malaria, because initial trials showed poor efficacy against P. vivax. P. vivax cannot be grown in culture; the reason for its resistance to DHFR inhibitors is unknown. We show that, like P. falciparum, point mutations in the dhfr gene can cause resistance to pyrimethamine in P. vivax. WR99210 is a novel inhibitor of DHFR, effective even against the most pyrimethamine-resistant P. falciparum strains. We have found that it is also an extremely effective inhibitor of the P. vivax DHFR, and mutations that confer high-level resistance to pyrimethamine render the P. vivax enzyme exquisitely sensitive to WR99210. These data suggest that pyrimethamine and WR99210 would exert opposing selective forces on the P. vivax population. If used in combination, these two drugs could greatly slow the selection of parasites resistant to both drugs. If that is the case, this novel class of DHFR inhibitors could provide effective and affordable treatment for chloroquine- and pyrimethamine-resistant vivax and falciparum malaria for many years to come.     

Prevalence of malaria in Aligarh

In Aligarh Plasmodium vivax and Plasmodium falciparum infections during 1998 and 1999 were 69.6% and 62.2%, and 30.4% and 37.8%, respectively. Peak transmission of malaria with highest slide positivity rates (38-44.6%) and slide P. falciparum rates (13 to 16%) were recorded during the months of September and October. About 7.5 to 10% cases showed resistance to chloroquine in P. falciparum infections while 11.3 to 16% P. vivax cases relapsed after getting required doses of chloroquine. About 75% of relapsing cases were of short-term type. Patients who were given both chloroquine and primaquine also relapsed but frequency was less (3.17%). A few chloroquine resistant cases were recorded in patients suffering from vivax malaria.     

Chloroquine/doxycycline combination versus chloroquine alone, and doxycycline alone for the treatment of Plasmodium falciparum and Plasmodium vivax malaria in northeastern Irian Jaya, Indonesia.

Combination therapy is one method of overcoming the global challenge of drug-resistant Plasmodium falciparum malaria. We conducted a hospital-based 28-day in vivo test comparing chloroquine/doxycycline to chloroquine or doxycycline alone for treating P. falciparum and Plasmodium vivax malaria in Irian Jaya, Indonesia. Eighty-nine patients with uncomplicated falciparum malaria were randomized to standard dose chloroquine (n = 30), doxycycline (100 mg every 12 hours [7 days], n = 20), or chloroquine with doxycycline (n = 39); corresponding numbers for vivax malaria (n = 63) were 23, 16, 24. Endpoints were parasite sensitivity (S) or resistance (RI/RII/RIII). Of the 105 evaluable patients, chloroquine/doxycycline cured (S) 20/22 (90.9% [95% CI 78.9-100%]) patients with P. falciparum malaria; 2/22 (9.1% [0-21%]) were RIII resistant. Doxycycline cured 11/17 (64.7% [42.0-87.4%]) patients, and chloroquine 4/20 (20% [2.5-37.5%]). Against P. vivax, chloroquine/doxycycline cured (S) 12/17 (70.6% [48.9-92.2%]) patients, doxycycline 4/12 (33.3% [6.6-59.9%]), and chloroquine 5/17 (29.4% [7.7-51.1%]). Chloroquine/doxycycline was effective against P. falciparum but only modestly effective against P. vivax. These findings support the use of chloroquine/doxycycline as an inexpensive alternative to mefloquine for treating chloroquine-resistant P. falciparum but not chloroquine-resistant P. vivax in this setting.     

间日疟、恶性疟混合感染1例治疗报告

2009年龙岩市报告1例间日疟、恶性疟混合感染病例,患者在国外感染、发病,曾接受过治疗,回国后再次发病。在国内经3个疗程青蒿琥酯(1 800 mg)和4个疗程的氯伯8 d疗法(氯喹4 800 mg、伯氨喹720 mg)治疗后痊愈。     

Assessment of therapeutic efficacy of chloroquine for vivax malaria in Thailand

Chloroquine-resistant Plasmodium vivax has been reported in some Asian countries. In 2003, 161 patients infected with vivax malaria were treated according to the Thai National Drug Policy, with oral chloroquine (approximately 25 mg base/kg body weight, administered over 3 days) followed by primaquine on day 28 (15 mg daily for 14 days). All the patients were initially cured after chloroquine treatment, clearing their parasitemias within 7 days. Only one patient presented with parasitemia at 28 days. These data indicate that chloroquine is still effective for the treatment of patients with vivax malaria in Thailand.     

Resistance to chloroquine by Plasmodium vivax in Irian Jaya, Indonesia.

Evidence of emerging resistance to chloroquine by Plasmodium vivax is described from Irian Jaya (Indonesian New Guinea). Sixteen of 24 residents in the village of Arso PIR II taking supervised weekly chloroquine prophylaxis (5 mg base/kg) had asexual parasitemia with P. vivax at least once during eight weeks of surveillance. An American working in the same village developed symptomatic P. vivax parasitemia despite chloroquine prophylaxis. Five days after therapy with 600 mg chloroquine base, the asexual parasitemia in the American increased 40-fold, but cleared after treatment with 1,500 mg chloroquine base. Serum samples were not available from many of the cases, but six local residents and the American had serum levels of chloroquine in excess of the ordinarily suppressive 15 ng/ml at the time of their asexual parasitemias (16-70 ng/ml). The weekly 300 mg base tablet of chloroquine, which has been the standard for prophylaxis against malaria for more than 40 years, was not effective against P. vivax in Arso PIR, Irian Jaya.     

Chloroquine sensitivity of Plasmodium vivax in Thailand

Chloroquine has been the standard treatment for Plasmodium vivax malaria for more than 40 years in most regions of the world. Recently, however, chloroquine-resistant P. vivax has been reported from Oceania, several parts of Asia, and South America. In order to assess the situation in Thailand, 886 patients with vivax malaria who were admitted to the Bangkok Hospital for Tropical Diseases from 1992 to 1997 were followed prospectively. Most of the patients had been infected on the western border of Thailand and were experiencing their first malarial infection when admitted. All received oral chloroquine (approximately 25 mg base/kg body weight, administered over 3 days) and then were randomized to receive primaquine (15 mg daily for 14 days) or no further treatment. All the patients were initially responsive to chloroquine, clearing their parasitaemias within 7 days, and there were no significant differences in the clinical or parasitological responses between those treated with primaquine and those given no further treatment. Plasmodium vivax parasitaemias re-appeared within 28 days of chloroquine treatment in just four patients. In each of these four cases, re-treatment with the same regimen of chloroquine resulted in eradication of the parasitaemia, with no further appearance of parasitaemia during the next, 28-day, follow-up period. These data indicate that virtually all acute (i.e. blood-stage) P. vivax infections acquired in Thailand can still be successfully treated with chloroquine.     

Rapid immunochromatography-based detection of mixed-species malaria infection in Pakistan

We report the identification of mixed Plasmodium infections in four recent patients with malaria clinically refractory to empiric chloroquine therapy using the rapid antigen detection kit, NOW ICT Malaria Pf/Pv. A rapid in vitro immunodiagnostic test, the NOW ICT Malaria Pf/Pv test kit was used for the detection of circulating Plasmodium falciparum (Pf) and Plasmodium vivax (Pv) antigens in whole blood. Peripheral blood microscopy confirmed mixed-species infection in all the cases. Thick and thin peripheral blood films were made and stained with Giemsa stain and examined by both hospital laboratory staff and an experienced parasitologist who was blinded to the results of the rapid malarial antigen tests. Four recent patients (all male; mean age, 24 years) with mixed malarial infection were identified. All the subjects were males working for an oil company in a coastal area of Pakistan, and all had been diagnosed presumptively with malaria based on clinical grounds (without microbiologic confirmation), and were treated empirically with chloroquine without clinical response. Semiquantitative malaria counts via microscopy were as follows: P. vivax, scanty (2 patients) and moderate (2 patients); for P. falciparum--scanty (1 patient), moderate (2 patients), and heavy (1 patient). The present case series, although limited by the small number of patients with proven mixed P. falciparum-P. vivax infection, highlights the usefulness of the rapid antigen test in a highly malarious region of Pakistan where chloroquine resistance is prevalent. Although there was full concordance between the results of blood smear microscopy and rapid antigen testing, these techniques are potentially most useful when there is a discrepancy with microscopy findings. Accurate and rapid diagnosis of parasites, particularly in cases of mixed P. falciparum and P. vivax infection, is of immense importance for individual patient management and in reducing the burden of disease, especially in regions of chloroquine resistance.