Short report: prevalence and chloroquine sensitivity of Plasmodium malariae in Madagascar

We report the results of clinical studies carried out at six sites in Madagascar, between January and October 2006. The aims were (i) to update our knowledge of the burden of Plasmodium malariae infection and (ii) to assess the therapeutic efficacy of chloroquine for uncomplicated quartan malaria. Our findings confirm that P. malariae is the third leading cause of malaria, accounting for 1.1% of all malarial infections. They also demonstrate that chloroquine-currently recommended for the home management of presumed malaria in children under the age of five years and commonly used by adults-remains highly effective in patients with uncomplicated P. malariae infection.     

Prevalence of malaria and economic loss in two major iron ore mines in Sundargarh district, Orissa.

A cross-sectional study on malaria was undertaken in May 1989 in the settlements of Kalta and Barsuan iron ore mines situated in a hilly area of Sundargarh district. Fever surveys revealed slide positivity rates of 33.9% and 34.8% in Kalta and Barsuan, respectively. Malaria infection rates as recorded through mass blood surveys in the resident population were 23.5 and 13.8%, respectively. Children up to 9 years age suffered most from malaria and in the age group of 2-9 years 37.3%, children had enlarged spleens with an average enlarged spleen (AES) index of 1.7. P. falciparum was the most prevalent species followed by P. vivax and P. malariae. Malaria vectors viz., An. fluviatilis and An. culicifacies were present in high densities. The present paper also brings out the economic loss due to malaria to the mining industry.     

Re-emergence of Plasmodium malariae in Trinidad, West Indies

A focus of Plasmodium malariae infection has recently occurred on the island of Trinidad, some 30 years after a successful eradication programme. Examination of bloodsmears revealed 22 cases of P. malariae in the Nariva-Mayaro area of Trinidad between August 1994 and September 1995. Most (77%) of the cases were male and, as seven were aged < 25 years of age, it appeared that transmission had been renewed, probably by the vector Anopheles bellator. However, none of the 3000 mosquitoes tested by ELISA for the circumsporozoite protein of P. malariae proved positive. Use of IFAT to check blood samples for P. malariae appeared more sensitive than direct examination of bloodsmears, indicating that 42 (13%) of the 325 samples tested were seropositive (at titres of 1:256 or greater). The levels of transmission of the parasite may therefore be even higher than indicated by examination of bloodsmears. The surveillance measures adopted to understand the epidemiology of this outbreak of P. malariae in Trinidad are described. The need to maintain malaria surveillance in all the countries where P. malariae parasites once existed (prior to eradication) is emphasised.     

Present status of Plasmodium malariae infection in Bastar District (M.P.)

Plasmodium malariae infection was detected in Bastar district (M.P.) during malaria survey in 1981-83. The data collected during the survey was compared with the earlier records of P. malariae infection in the area. From the data it can be seen that the infection in this area has declined due to the ecological/developmental activities undertaken by Government. All the cases were found to be indigenous and approximately 62 per cent infection was found in age group of 10-14 years irrespective of sex. More than 60 per cent of P. malariae infections were positive for gametocytes. Three day regimen of 4-aminoquilines for the treatment was found quite effective.     

The seroepidemiology of malaria in Middle America. II. Studies on the Pacific coast of Costa Rica.

Serologic studies for malaria using the indirect fluorescent antibody technique suggest that active transmission is either absent or very low in 6 villages on the Pacific side of Costa Rica. Positive titers (1:20 or higher) were seen in the under-15-year age group in three of the study localities, but only 5 such responses were encountered among 249 people examined in this age range. In the adults (15 years and over) from the same 3 villages there were 68 positive titers among 161 examined. There were 43 positive responses in 189 adults from the remaining 3 villages where none of 307 persons under 15 years of age showed a titer of 1:20 or higher to any of the 3 malaria antigens tested (Plasmodium falciparum, P. vivax and P. malariae). These data suggest that the positive responses in the latter villages are more likely to be associated with old or imported cases than with current local transmission. Serologic responses of 1:80 or higher to the P. falciparum antigen suggested the continued presence of this parasite in the population in spite of the paucity of positive blood smears with this species in recent years. Positive titers with the P. malariae antigen suggest that this parasite is probably still present in the area. Such serologic studies help to indicate areas where malaria transmission is active and provide information on parasite reservoirs in particular populations.     

Malaria control by chlorproguanil. I. Clinical effects and susceptibility of Plasmodium falciparum in vivo after seven years of monthly chlorproguanil administration to children in a Liberian village

For seven years, chlorproguanil (1.0 to 2.0 mg kg-1) was administered monthly to the children below 15 years of age in a village with holoendemic malaria. Malariometric indices were recorded every six months. Susceptibility in vivo was monitored by the clearance of Plasmodium falciparum parasitaemia after drug intake. Three parasite species were found initially: P. falciparum (52%), P. malariae (8%) and P. ovale (4%). The parasites found during the study were mainly P. falciparum, and parasite rates ranged from 37 to 87% at the different surveys one month after respective drug intake. A fifty-fold decrease of mean parasite density was generally observed seven days after drug intake. Splenomegaly was initially recorded in all two to nine year old children, with a mean size of 2.64 according to Hackett's index. From 18 months onwards as the mean spleen index was 1.15 in the same age group. Chlorproguanil may represent an important alternative drug to groups at risk in malaria control schemes.     

Different malaria control activities in an area of Liberia--effects on malariometric parameters

The epidemiology of malaria was studied in a West African mining town (Yekepa) and three surrounding zones defined as Close, Middle and Far areas. Malariometric parameters were investigated in children two to nine years of age at the end of the rainy season. In Yekepa, vector control measures and intense suppression of malaria with drugs had created an almost hypoendemic situation with a spleen rate of 11%. In Close area, vector control was applied to some extent and malaria drugs were frequently used for treatment; the spleen rate was 40%. In Middle area, a mobile clinic provided sporadic malaria treatment to small children, but the clinic did not reach out to Far area. The spleen rates were 95 and 99%, respectively. Three species of Plasmodium were found in all areas. The prevalences in Far area were P. falciparum 82%, P. malariae 39% and P. ovale 9%. The crude parasite rates increased from 13% in Yekepa to 92% in Far area, whereas haematocrit levels decreased from 37.6 to 35.2, respectively. Plasmodium falciparum seropositivity, as measured by indirect immunofluorescence, was 74% in Yekepa and 99% in Middle and Far areas. Total IgG concentrations ranged from 18 g1(-1) in Yekepa to 33 g1(-1) in Far area. Three main anopheline species were found in the zones outside Yekepa. Their relative frequencies in Far area were Anopheles funestus 45%, A. hancocki 37%, and A. gambiae 18%. The local inoculation rates gradually increased outwards from Yekepa from less than 0.01 to 0.17 inoculations per man and night at the beginning of the dry season.(ABSTRACT TRUNCATED AT 250 WORDS)     

Imported malaria in Trinidad and Tobago, W.I. (1968-1986)

Malaria surveillance was conducted by the Insect Vector Control Division, Ministry of Health, to determine the number of imported cases of malaria which entered Trinidad and Tobago from 1968 to 1986. A total of 84 cases of imported malaria was detected; in 44 the agent was Plasmodium falciparum, in 25 P. vivax, in 11 P. malariae, in one P. ovale, and three were mixed. The monthly incidence of malaria showed that July and August accounted for 41% of all imported malaria cases. Most malaria cases were diagnosed among male patients (74.3%) whereas the most significant age group contracting malaria was 20-29 years. Twenty-seven per cent of the persons contracting malaria were Trinidadians, while tourists, seamen and contract officers accounted for 21%. The African continent was responsible for 60%. India 25% and South America 12% of the imported malaria cases diagnosed and treated in Trinidad. Trinidadians of African and East Indian descent accounted for 78% of all imported malaria cases. Malaria resistance and relapse are discussed. The need to maintain port surveillance is emphasized.     

Heightened transmission of stable malaria in an isolated population in the highlands of Irian Jaya, Indonesia.

Malaria at an elevation of 1,500 meters is uncommon and is usually unstable when it occurs. To confirm reports of a recent increase in transmission of stable malaria in the Oksibil Valley, which is at an elevation of 1,250-1,500 meters in the Jayawijaya Mountains of Irian Jaya, Indonesia, five malariometric surveys were conducted in four villages between May 1990 and July 1991. A total of 3,380 blood smears, representative of 1,949 persons, was examined. Prevalence rates over the survey period were consistent in each of the four villages, averaging 10% for infants, 50% for children 1-4 years of age, 35% for those 5-9 years old, 28% for those 10-14 years old, and 16% for adults (greater than 15 years old). The spleen rate for the those less than five years old was 96%, with an average enlarged spleen score of 2.32. Plasmodium falciparum accounted for 55% of the infections in the valley, but P. vivax was the predominant species in those less than 10 years old. In the village of Kutdol at an elevation of 1,500 meters, P. malariae was identified in 43% of the positive smears. Four cases were diagnosed as P. ovale. Infection with P. falciparum without obvious clinical symptoms was common in both adults and children. Entomologic and epidemiologic data suggested that the recent upsurge in transmission coincided with the replacement of traditional village huts with the more modern social housing. This replacement required the extensive construction of drainage ditches, which inadvertently also served as additional vector breeding sites. We suspect that this manipulation of the environment, in an effort to improve the quality of life, created conditions conductive for heightened transmission of stable malaria.     

Malaria endemicity among Orang Asli (Malaysian aborigines) as determined by indirect fluorescent antibody tests.

Fluorescent antibodies were detected in 89% of 288 Orang Asli (Malaysian aborigines) with Plasmodium falciparum antigen and in 62% with P. brasilianum (for P. malariae) antigen. Blood films from 18 donors were positive for P. falciparum; 2 of them had mixed infection with P. vivax. Seven of the P. falciparum-positive blood films were from children in the 2- to 9-year age group. Of 17 sera from cord blood, 16 had significant levels of P. falciparum antibody and 14 of P. malariae antibody, the levels being the same as those of the mothers. None of these babies had congenital malaria. A higher percentage of male donors reacted to both antigens. There was an age dependent increase in the number positive and the maximum titers.     

云南腾冲市2000~2015年本地感染疟疾疫情流行病学分析

目的  分析腾冲市2000~2015年本地感染疟疾疫情特征,为消除疟疾防控工作提供科学依据。 方法  收集腾冲市2000~2015年本地感染疟疾疫情资料,采用Microsoft Excel 2010软件对数据进行整理分析。 结果  2000~2015年,腾冲市共报告本地感染疟疾病例239例,间日疟170例,占71.13％（170/239）,恶性疟67例,占28.03％（67/239）,三日疟1例,间日疟、恶性疟混合感染1例。发病年龄最小为1个月,最大为78岁,男女性别比例为1.85:1。职业以农民和民工为主。6~7月为发病高峰季节,6月发病数最多,占41.88％（124/239）。 结论  腾冲市为间日疟、恶性疟混合流行区,同时存在三日疟,病例以间日疟为主;本地感染疟疾呈低水平、散发趋势,自2013年起已无本地感染病例报告。     

Transfusion-transmitted malaria: case report of asymptomatic donor harboring Plasmodium malariae

Malaria in Brazil is endemic in the Amazon region, but autochthonous cases with low parasitaemia occur in the Atlantic Forest area of the country. According to Brazilian legislation no test is mandatory for blood donors from non-endemic areas. However if they have traveled to malaria transmission regions they are deferred for six months before they can donate. This report describes a transfusion-transmitted malaria case in Sao Paulo, Brazil, where one recipient received infected blood and developed the disease. He lived in Sao Paulo and had no previous transfusion or trips to endemic areas, including those of low endemicity, such as Atlantic Forest. Thick blood smears confirmed Plasmodium malariae. All donors lived in Sao Paulo and one of them (Donor 045-0) showed positive hemoscopy and PCR. This asymptomatic donor had traveled to Juquia, in the Atlantic Forest area of S ao Paulo State, where sporadic cases of autochthonous malaria are described. DNA assay revealed P. malariae in the donor's (Donor 045-0) blood. Serum archives of the recipient and of all blood donors were analyzed by ELISA using both P. vivax and P. falciparum antigens, and IFAT with P. malariae. Donor 045-0's serum was P. malariae IFAT positive and the P. vivax ELISA was reactive. In addition, two out of 44 donors' archive sera were also P. vivax ELISA reactive. All sera were P. falciparum ELISA negative. This case suggests the need of reviewing donor selection criteria and deferral strategies to prevent possible cases of transfusion-transmitted malaria.     

Abnormal haemoglobins in the Sudan savanna of Nigeria. III. Malaria, immunoglobulins and antimalarial antibodies in sickle cell disease.

Subjects with sickle cell disease were identified in (i) a whole population sample (2742) Garki District, Kano State, Nigeria, and in (ii) the 534 infants born into the population during five years. Eleven (2.1%) newborn had Hb.SS, as was expected from gene frequency (0.146). Prevalence was maintained in the first year of life, but fell to 0.4% at one to four years and to 0.05% (one person) over the age of nine years. Antimalarial intervention for two transmission seasons was followed by an apparent but not significant decrease in Hb.SS mortality. There was one male aged about 40 years who had Hb.SC (the expected number was three). Hb.SS children were compared to normal subjects at the same age, the same village and the same survey; they had significantly less than the expected Plasmodium malariae infection (P less than 0.01) and lower than median P. falciparum densities while below five years (P less than 0.05). Over one year of age, they tended to have below average indirect fluorescent antibody (IFA) (P less than 0.01), indirect haemagglutinating antibody (IHA) (P less than 0.01) titres and number of precipitin rings (not significant) against P. falciparum antigen, and IFA against P malariae (P less than 0.01). They had above average IgM (P less than 0.05), but their IgG concentrations did not differ from normal. We conclude that (i) sickling is sufficient to protect against P. malariae in Hb.SS but not Hb.AS; (ii) sickling prevents intense P. falciparum infection in Hb.SS, as in Hb.AS; (iii) in Hb.SS, there is less antigenic stimulus and hence less antibody against P. falciparum (like Hb.AS) and P. malariae (unlike Hb.AS); (iv) although less intense, malaria is frequently fatal in Hb.SS, especially in age-group one to four years (unlike Hb.AS); (v) IgM levels are high in Hb.SS in response to frequent infections other than malaria (unlike Hb.AS).     

A preliminary survey of malaria in Occidental, Mindoro, Philippines

A survey of malaria in Northwest Mindoro, Occidental, Mindoro, Philippines is reported. Three species of human plasmodia were identified from 600 blood films examined. The overall prevalence of malaria was 7% (2.8% P. falciparum, 4.3% P. vivax, 0.7% P. malariae). The prevalence of malaria was highest (24%) among children 0 to 15 years of age and only 4 cases (12%) were found among persons over the age of 15. Males and females were equally infected. Study sites with the highest slide-positivity rate were located in the foothill regions which corresponded with the observed presence of two malaria vectors, Anopheles minimus flavirostris and An. maculatus. These sites appeared to be adequate for future studies of drug-resistance, although large numbers of suitable candidates would not be expected.     

上海市1例输血性三日疟病例的实验室检测分析与诊断

目的 目的 对1例感染源不明的三日疟病例进行实验室检测分析并确诊。 方法 方法 收集该病例的临床资料, 并进行流行病学调查。对患者及其供血者的血样进行血涂片病原学检查、 疟疾快速诊断检测 （RDT） 和巢式PCR检测, 并对阳性结果进行测序比对。 结果 结果 该患者无疟疾流行区居留史和既往疟疾感染史, 有外科手术时大量输血史。外周血涂片镜检查见三日疟原虫。流行病学调查显示, 该患者接受了3位供血者的血液, 但3位供血者血样经血涂片镜检、 RDT和巢式 PCR检测均未查见疟原虫, 后经改进的巢式?多重PCR检测及结果测序比对后显示, 与其中1名非洲籍留学生供血者的阳性扩增条带具100%同源性。 结论 结论 该病例因输血而感染三日疟。实验室检测疟疾疑难病例需经多方法验证方可确诊, 改进的巢式?多重PCR方法对低密度疟原虫感染有较好的检测效果。     

Malaria: a 10-year (1994-2003) retrospective study at University Malaya Medical Center (UMMC), Kuala Lumpur, Malaysia

Malaria is still one of the most important vector-borne diseases in Malaysia, particularly in remote areas. This retrospective study was carried out to find the prevalence of malaria among patients admitted to UMMC Kuala Lumpur, from 1994-2003. A total of 86 malaria cases were analyzed. Most cases occurred among foreigners [57% (49 cases)] while Malaysians constituted 43% (37 cases). Among foreigners, Indonesians constituted the most [57% (28 cases)]. Among Malaysians, most cases occurred among the Chinese [35% (13 cases)] followed by the Malays [30% (11 cases)]. Males [70%(60 cases)] were more commonly affected. The majority of cases were within the 20-39 year age group (69%). Three species of malaria parasites were reported, of which Plasmodium vivax constituted the most [55%( 47 cases)], followed by Plasmodium falciparum [29% (25 cases)], and only four cases (5%) of Plasmodium malariae. Nine percent (8 cases) were mixed infections. In this study, 12%(10 cases) developed chloroquine resistance: 7 cases of P. falciparum, and 3 cases of P. vivax. The most common complications were jaundice and anemia [77% (23 cases)], followed by blackwater fever [13% (4 cases)] and cerebral malaria [10% (3 cases)]. Most of the complications were due to P. falciparum [43% (13 cases)]. There were no reported deaths. This new source of malaria coming from foreigners must be given serious attention, as it has great potential of increasing malaria cases in urban Malaysia.     

Clinical evaluation of antimalarial drugs

We have analyzed the clinical data of 189 patients with malaria to establish antimalarial regimens in Japan. The causative parasite species were Plasmodium falciparum in 56 cases (30%), P. vivax in 132 (70%) and P. malariae in 1 (1%). The outcomes f malaria cases are as follows: Cure rats in falciparum and vivax malaria are 86% and 91%, respectively. Two patients died of falciparum malaria and recurrence occurred in 6 cases (11%) of falciparum malaria. Relapse was seen in 12 (9%) of vivax malaria. Chloroquine was most frequently used among antimalarial agents (in 123 cases, 65% of the total) for suppressing acute attacks. The efficacy of chloroquine was evaluated by classifying each case into three groups: chloroquine alone in group one, chloroquine in combination with other antimalarials in group two and other antimalarials except chloroquine in group three. The cure rate among each group is about 80% and there is no difference among them. However, it is noticeable that recurrence occurred when patients were treated with a combination of chloroquine and quinine. We have found a similar result as this in another old report in Japan. Primaquine is effective for eliminating hepatic tissue schizonts but in this study, relapse occurred in 12 cases of vivax, although primaquine had been used in 10 out of 12 cases. In primaquine group, relapse occurred at a similar rate between chloroquine and Fansidar cases. Further studies are needed to decide whether a larger dose of primaquine is appropriate for treatment of vivax malaria. Recovery periods from fever and parasitemia were compared between chloroquine and Fansidar cases.(ABSTRACT TRUNCATED AT 250 WORDS)     

Epidemiological analysis of 133 malaria cases in Shanxian County,Shandong Province,China

Objective: To conduct an analysis of the epidemiological changes in malaria that have occurred in Shanxian county from 2002 to 2016. Methods: A retrospective study was conducted and data were collected from web-based reporting system to explore the epidemiological characteristics in Shanxian county from 2002 to 2016. All individual case information was obtained from village malaria servicers organized by the local Shandong Institute of Parasitic Diseases. Results: A total of 133 cases were identified as malaria in Shanxian county during this period, including 124 indigenous cases(93.2%) and 9 imported cases(6.8%). The 124 indigenous malaria cases were infected with Plasmodium vivax(P. vivax), whereas 7 of the 9 confirmed imported cases were infected with Plasmodium falciparum(P. falciparum), 1 was infected with Plasmodium ovale(P. ovale) and 1 patient was infected with P. falciparum mixed with P. vivax. The total number of malaria cases included 86 males(64.7%) and 47 females(35.3%). Age of the patients ranged from 1 to 83 years, although most(64.7%) infections occurred in the 21-to 60-year-old age group. Remarkably, 117 of the total malaria cases(98.0%) were reported from 2006-2011. The epidemic season was from June to October, with the peak occurring yearly from July to September. The most common occupation of the infected patients was farmer. In total, 58.1% of the cases occurred in 3 townships, namely, Fugang, Huanggang and Caozhuang. Conclusions: In Shanxian county, the local malaria incidence experienced an emerge-peak-control-eliminate status. However, due to the numbers of migrant labourers returning from Africa, imported cases were continuous and presented an increasing annual trend, which became a non-negligible and a significant impediment for malaria elimination. Therefore, the need to eliminate instances of malaria reintroduction to receptive malaria-free areas should drive strategies to align with the epidemiological changes.     

Epidemiological profile of malaria in the state of Tocantins, Brazil, from 2003 to 2008

This study describes the epidemiological profile of malaria in the State of Tocantins, in the period 2003-2008, investigates the association between the frequency of malaria and population growth, classifies the cases by 'autochthonous' and 'imported', reports the indices of the disease and analyses the distribution of the cases by Plasmodium species, age and gender. The retrospective study was based on secondary data, stored in SIVEP-malaria and analyzed using the software Epi-Info 3.5.1. and Bioestat 5.0. 19,004 samples were investigated for malaria, 19% of them were positive, 73.32% with Plasmodium vivax, 21.80% with Plasmodium falciparum, 4.79% with mixed infections and only 0.08% with Plasmodium malariae. Male individuals accounted for 76.95% and predominated in all years and age groups, especially in the 15 to 49 years old group. From the overall cases, 34.27% were autochthonous and 65.73% were imported (χ2 = 356.8, p = 0.0001). The frequency of malaria decreased significantly during the entire series (rp = 0.96, p = 0.002) and the number of municipalities with autochthonous transmission also diminished. It was found that malaria is predominantly imported, related to land activities, which confirms the need for effective measures to maintain vigilance throughout the state and enhance educational activities in order to guide the population towards early treatment-seeking.     

2017—2021年福建省输入性疟疾疫情分析

目的 分析2017—2021年福建省输入性疟疾的疫情特征,为消除疟疾后的防控工作提供科学参考。方法 收集2017—2021年福建省输入性疟疾的疫情资料,运用Microsoft Excel 2010软件对病例的感染分型、感染来源、三间分布、就诊和诊断情况等进行描述性分析。结果 2017—2021年福建省共报告境外输入性疟疾病例407例,均为实验室确诊病例,其中恶性疟307例(75.43%)、间日疟46例(11.30%)、卵形疟34例(8.36%)、三日疟16例(3.93%)、混合感染4例(0.98%)。感染来源为非洲30个国家(376例,92.38%)、亚洲5个国家(18例,4.42%)、大洋洲1个国家(12例,2.95%)和南美洲1个国家(1例,0.25% );主要由福州市(314例,77.15%)报告。人群分布以男性为主(363例,89.19%),年龄主要集中在30~50岁(256例,62.90%)。病例主要在医疗机构初诊(389例,95.58%)、确诊(377例,92.63%)和报告(393例,96.56%),初诊正确率为71.25%(290/407)。发病-初诊、初诊-确诊、发病-确诊的时间间隔中位数分别为2 d、0 d和3 d。 结论 福建省仍面临严峻的境外输入性疟疾的持续性挑战,需继续加强对输入性疫情的监测,巩固疟疾消除成果。