Imported malaria: a possible threat to the elimination of malaria from Sri Lanka?

To assess the impact of intensified malaria control interventions in an ethnic minority community in Betul using existing tools. Two rounds of indoor residual spraying with synthetic pyrethroid insecticide were applied and larvivorous fish introduced, followed by intensive surveillance for early detection of Plasmodium falciparum with rapid diagnostic tests and prompt treatment with sulphadoxine pyrimethamine. Pre-intervention surveys revealed a very high fever rate in the community in all age groups with a slide positivity rate of >50% with >90%P. falciparum. The post-intervention phase showed a sharp steady decline in number of malaria cases (beta 0.972; P < 0.0001, 95% CI 0.35-0.47). Monitoring of entomological results revealed a significant decline in both Anopheles species and An. culicifacies (P < 0.0001). A combination of indoor residual spraying and early detection and prompt treatment complemented by rapid diagnostic tests and larvivorous fishes successfully brought malaria under control. These approaches could be applied in other regions of different endemicity to control malaria in India.

BackgroundCross-border malaria transmission poses a challenge for countries to achieve and maintain malaria elimination. Because of a dramatic increase of cross-border population movement between China and 14 neighbouring countries, the malaria epidemic risk in China’s land border regions needs to be understood.MethodsIn this study, individual case-based epidemiological data on malaria in the 136 counties of China with international land borders, from 2011 to 2014, were extracted from the National Infectious Disease Information System. The Plasmodium species, seasonality, spatiotemporal distribution and changing features of imported and indigenous cases were analysed using descriptive spatial and temporal methods.ResultsA total of 1948 malaria cases were reported, with 1406 (72.2%) imported cases and 542 (27.8%) indigenous cases. Plasmodium vivax is the predominant species, with 1536 malaria cases occurrence (78.9%), following by Plasmodium falciparum (361 cases, 18.5%), and the others (51 cases, 2.6%). The magnitude and geographic distribution of malaria in land border counties shrunk sharply during the elimination period. Imported malaria cases were with a peak of 546 cases in 2011, decreasing yearly in the following years. The number of counties with imported cases decreased from 28 counties in 2011 to 26 counties in 2014. Indigenous malaria cases presented a markedly decreasing trend, with 319 indigenous cases in 2011 reducing to only 33 indigenous cases in 2014. The number of counties with indigenous cases reduced from 26 counties in 2011 to 10 counties in 2014. However, several bordering counties of Yunnan province adjacent to Myanmar reported indigenous malaria cases in the four consecutive years from 2011 to 2014.ConclusionsThe scale and extent of malaria occurrence in the international land border counties of China decreased dramatically during the elimination period. However, several high-risk counties, especially along the China–Myanmar border, still face a persistent risk of malaria introduction and transmission. The study emphasizes the importance and urgency of cross-border cooperation between neighbouring countries to jointly face malaria threats to elimination goals.

The impact of HIV infection on malaria is unclear in nonendemic areas. In endemic territories, HIV has been reported to be a risk factor for higher morbidity. Nowadays, as HIV-infected patients travel more, it is important to assess the impact of HIV at the individual level on imported malaria. This retrospective case-control study collected data on HIV-infected patients diagnosed with malaria (2000-2017) and matched them with two controls based on age, sex and ethnicity. Clinical and biological parameters were collected and compared. We identified 47 cases and matched them with 94 controls. Comparing each of the WHO 2014 severity criteria, hyperparasitemia above 10% (P = 0.006; 12.8 versus 1.1%), icterus (P = 0.042; 14.9 versus 4.3%), acute renal failure (P = 0.022; 25.5 versus 9.6%) and bacteraemia (P = 0.014; 6.4 versus 0%) were significantly more present in HIV-infected patients with a trend to more cerebral malaria (12.8 versus 6.4%). HIV- infected patients were hospitalized more frequently and for longer periods. We observed a higher number of severity criteria when CD4 T-cell count was lower, especially below 200 cells/μl. The difference in occurrence of severe malaria disappeared when patients with CD4 T-cell count more than 500 cells/μl and undetectable viral load (n = 9) were compared with controls. De-novo HIV diagnosis was made during the malaria episode in 17% of cases. HIV infection has an impact on the imported malaria profile, although it is unclear whether well controlled HIV-infected patients have a higher risk of severe malaria. HIV-infected patients should be particularly targeted for pretravel advice.

BackgroundImported malaria continues to be reported in Sri Lanka after it was eliminated in 2012, and a few progress to life-threatening severe malaria. MethodsData on imported malaria cases reported in Sri Lanka from 2013 to 2023 were extracted from the national malaria database maintained by the Anti Malaria Campaign (AMC) of Sri Lanka. Case data of severe malaria as defined by the World Health Organization were analysed with regard to patients’ general characteristics and their health-seeking behaviour, and the latter compared with that of uncomplicated malaria patients. Details of the last three cases of severe malaria in 2023 are presented.Results532 imported malaria cases were diagnosed over 11 years (2013–2023); 46 (8.6%) were severe malaria, of which 45 were Plasmodium falciparum and one Plasmodium vivax. Most severe malaria infections were acquired in Africa. All but one were males, and a majority (87%) were 26–60 years of age. They were mainly Sri Lankan nationals (82.6%). Just over half (56.5%) were treated at government hospitals. The average time between arrival of the person in Sri Lanka and onset of illness was 4 days. 29 cases of severe malaria were compared with 165 uncomplicated malaria cases reported from 2015 to 2023. On average both severe and uncomplicated malaria patients consulted a physician equally early (mean = 1 day) with 93.3% of severe malaria doing so within 3 days. However, the time from the point of consulting a physician to diagnosis of malaria was significantly longer (median 4 days) in severe malaria patients compared to uncomplicated patients (median 1 day) (p = 0.012) as was the time from onset of illness to diagnosis (p = 0.042). All severe patients recovered without sequelae except for one who died.ConclusionsThe risk of severe malaria among imported cases increases significantly beyond 5 days from the onset of symptoms. Although patients consult a physician early, malaria diagnosis tends to be delayed by physicians because it is now a rare disease. Good access to expert clinical care has maintained case fatality rates of severe malaria at par with those reported elsewhere.

BackgroundSri Lanka is a malaria-free country. However it remains surrounded by countries with endemic malaria transmission. Since the last indigenous case of malaria was reported in October 2012, only imported malaria cases have been diagnosed with 36 cases detected in 2015, which includes 17 cases each of Plasmodium vivax and Plasmodium falciparum and two cases of Plasmodium ovale.MethodsThis study investigated the knowledge and practices regarding malaria chemoprophylaxis among all the Sri Lankan security forces personnel returning from peacekeeping missions in malaria endemic countries over a 7 month period. Adherence to other malaria prevention measures, occurrence of adverse events and incident cases of malaria were also recorded maintaining the anonymity of the respondents. Potential associations for non-compliance were studied.ResultsInterviews were carried out with 559 security forces personnel returning home from foreign deployments in malaria-endemic regions (males: 550, 98.4 %). The majority (553, 98.9 %) was well aware of the need for chemoprophylaxis during the overseas stay and its regular use as prescribed. The overall adherence to chemoprophylaxis was good with 78.7 % (440/559) reporting regular, as prescribed, use. Having better educational qualifications, being female, being prescribed mefloquine, having fever during deployment and belonging to a security force other than the army were significantly associated with poor compliance (p < 0.05).ConclusionsThe study reveals that knowledge regarding malaria chemoprophylaxis among Sri Lankan security forces personnel serving abroad was good, a fact that may have contributed to absence/extremely low incidence of malaria during deployment.

BackgroundHubei Province, China, has been operating a malaria elimination programme. This study aimed at investigating the epidemiologic characteristics of malaria in Hubei Province (2005–2016) to plan resource allocation for malaria elimination.MethodsData on all malaria cases from 2005 to 2016 in all counties of Hubei Province were extracted from a web-based reporting system. The numbers of indigenous and imported cases during the disease control (2005–2010) and elimination (2011–2016) stages, as well as their spatiotemporal distribution, were compared.ResultsA total of 8109 malaria cases were reported from 2005 to 2016 (7270 and 839 cases during the control and elimination stages, respectively). Between 2005 and 2010, indigenous malaria cases comprised the majority of total cases (7114/7270; 97.9%), and Plasmodium vivax malaria cases accounted for most malaria cases (5572/7270; 76.6%). No indigenous malaria cases have been reported in Hubei Province since 2013. Imported malaria cases showed a gradually increasing trend from 2011 to 2016, Plasmodium falciparum was the predominant species in these cases, and the number of counties with imported cases increased from 4 in 2005 to 47 in 2016. During the control and elimination stages, the most likely spatial clusters for indigenous cases included 13 and 11 counties, respectively. However, the cluster of indigenous malaria cases has not been identified since September 2011. For imported cases, the most likely cluster and three secondary clusters during both stages were identified.ConclusionsHubei Province has made significant achievements in controlling and eliminating malaria; however, the region now faces some challenges associated with the increasing number and distribution of imported malaria cases. Priorities for malaria elimination should include better management of imported malaria cases, prevention of secondary malaria transmission, and ensuring the sustainability of malaria surveillance.

Objective To provide the basis for the surveillance to prevent re-transmission after malaria elimination by analyzing the diagnosis imported malaria cases in Shanxi Province during 2015-2019. Methods Data on imported malaria cases in Shanxi Province from 2015 to 2019 were collected and sorted through the National Infectious Diseases Information Reporting Management System (IDIRMS) and the Parasitic Diseases Information Reporting Management System (PDIRMS). Diagnostic institutions and diagnostic timeliness of imported malaria cases were described and analyzed by chi-square test and rank-sum test. Results A total of 72 imported malaria cases were reported in Shanxi during 2015-2019, all cases were imported from abroad, among which falciparum malaria accounted for 68.1% (49/72), vivax malaria 18.1% (13/72), ovale malaria 8.3% (6/72), malariae malaria 2.8% (2/72), and mixed infection 2.8% (2/72). And all of which were diagnosed with laboratory tests (100.0%). The rate of diagnosis in medical institutions was 95.8% (69/72), while 73.9% (51/69) were diagnosed in provincial medical institutions, 21.7% (15/69) were diagnosed in municipal medical institutions, 4.3% (3/69) of 69 cases diagnosed in medical institutions were diagnosed in county-level medical institutions. The median time from onset to diagnosis of malaria cases was 5 days, in which the median time from onset to first visit was 3 day. There were significant difference in the time both from onset to first visit and first visit to diagnosis ( P <0.05), the interquartile interval of malaria cases was shortened from the longest 10 days in 2017 to the shortest zero days in 2019. Conclusion Medical institutions in Shanxi Province play an important role in malaria case detection and monitoring. We should improve the diagnostic awareness and capabilities of county-level medical institutions, and to play the role of sentinel hospitals in the surveillance of preventing re-transmission after malaria elimination. 摘要:目的 分析山西省2015—2019年输人性疟疾病例诊断情况,为消除疟疾后防止输人再传播的监测工作提 供依据。 方法 通过传染病报告信息管理系统和寄生虫病防治信息管理系统,收集整理2015—2019年山西省疟疾病 例信息,对其诊断机构、诊断及时性等情况采用 χ 2 检验、秩和检验进行统计分析。 结果 2015—2019年全省共报告疟 疾病例72例,均为境外输人性病例,其中恶性疟占68.1%(49/72),间日疟占18.1%(13/72),卵形疟占8.3%(6/72),三日 疟占2.8%(2/72),混合感染2.8%(2/72)。所有病例均为实验室确诊病例,镜检检测率均为100.0%。95.8%(69/72)的病 例在医疗机构诊断,而69例在医疗机构诊断的病例中,73.9%(51/69)在省级医疗机构诊断,21.7%(15/69)在市级医疗 机构诊断,仅4.3%(3/69)在县级医疗机构诊断。疟疾病例从发病-确诊时间中位数为5 d,其中发病-初诊时间中位数 为3 d,发病-初诊和初诊-确诊时间各年份差异均有统计学意义,四分位数间距由2017年最长的10 d缩短为2019年最 短的0 d。 结论 山西省医疗机构在疟疾病例发现和监测中具有重要作用。疟疾病例诊断以省级医疗机构为主,提 示市、县级医疗机构的诊断水平较低。今后要加强市县级医疗机构的培训以提高其疟疾诊断意识和诊断能力。

BackgroundImported malaria cases continue to be reported in Sri Lanka, which was declared ‘malaria-free’ by the World Health Organization in September 2016. Chemoprophylaxis, a recommended strategy for malaria prevention for visitors travelling to malaria-endemic countries from Sri Lanka is available free of charge. The strategy of providing chemoprophylaxis to visitors to a neighbouring malaria-endemic country within the perspective of a country that has successfully eliminated malaria but is highly receptive was assessed, taking Sri Lanka as a case in point.MethodsThe risk of a Sri Lankan national acquiring malaria during a visit to India, a malaria-endemic country, was calculated for the period 2008–2013. The cost of providing prophylaxis for Sri Lankan nationals travelling to India for 1, 2 and 4 weeks was estimated for that same period.ResultsThe risk of a Sri Lankan traveller to India acquiring malaria ranged from 5.25 per 100,000 travellers in 2012 to 13.45 per 100,000 travellers in 2010. If 50% of cases were missed by the Sri Lankan healthcare system, then the risk of acquiring malaria in India among returning Sri Lankans would double. The 95% confidence intervals for both risks are small. As chloroquine is the chemoprophylactic drug recommended for travellers to India by the Anti Malaria Campaign of Sri Lanka, the costs of chemoprophylaxis for travellers for a 1-, 2- and 4-weeks stay in India on average are US$ 41,604, 48,538 and 62,407, respectively. If all Sri Lankan travellers to India are provided with chemoprophylaxis for four weeks, it will comprise 0.65% of the national malaria control programme budget.ConclusionsBased on the low risk of acquiring malaria among Sri Lankan travellers returning from India and the high receptivity in previously malarious areas of the country, chemoprophylaxis should not be considered a major strategy in the prevention of re-introduction. In areas with high receptivity, universal access to quality-assured diagnosis and treatment cannot be compromised at whatever cost.

Background: Malaria case management remains a crucial component of malaria control strategies. Despite the introduction of national malaria treatment guidelines and scale-up of malaria control interventions in Nigeria, shreds of evidence have shown some deviations from the guidelines in malaria case management. This study assessed compliance with national guidelines on the diagnosis and treatment of malaria among health workers in Anambra State.&#x0D; Materials and Methods: This comparative, cross-sectional hospital-based study was carried out among 360 healthcare workers selected from six Local Government Areas using a multistage sampling technique. A pre-tested interviewer-administered questionnaire was used to collect data on their socio-demographics and other vital information.&#x0D; Results: The findings of this study revealed that Ninety-eight respondents (54.4%) from public health facilities had adequate knowledge of malaria case management compared to 67 respondents (37.2%) from private health facilities (p=0.001). The overall level of compliance with the national guidelines shows that only 22.2% of the health workers interviewed strictly complied with the national guidelines. It was significantly higher among public healthcare workers (31.7%) compared to 12.8% of private health workers (p&lt;0.001). Training on malaria case management, access to national guidelines, availability of malaria diagnostic tools, and sex of the health workers were associated with compliance with national guidelines in both public and private health facilities (p&lt;0.001).&#x0D; Conclusion: The findings of this study revealed a close similarity between the two health facilities in the level of awareness of the national malaria treatment guidelines, but a remarkable difference in compliance to appropriate case management of malaria between public and private health facilities. Interventions to improve private sector engagement in the implementation of the guidelines, training, and supply of recommended anti-malarial medicines should be intensified.

Transfusion-associated malaria is a potentially serious complication that continues to pose risks in blood bank settings. There is a need for effective malaria screening of blood donations to improve on the current exclusion policies of potentially infected carriers on the basis of clinical and travel history. We evaluated the potential usefulness of ELISA screening for malaria antibody and P. falciparum antigen among Saudi blood donors. A total of 1756 donors were studied, 1100 from the malaria endemic Southern Region and 656 donors from the known malaria-free Riyadh area. The overall antibody prevalence for the antibody was 7.6%, in comparison to only 0.17% for the antigen. In the endemic region, the antibody positivity rate of 9.1% was almost double the rate in the non-endemic area (4.8%). There was no difference in the antigen prevalence rates; 0.18% in endemic and 0.15% in nonendemic areas. In malaria endemic countries like Saudi Arabia, excluding antibody-positive donations would result in too much wastage of blood units. However, antigen malaria testing appears to offer a potential utility, as only few donations would be rejected.

Objective To collect and analyze the epidemic regularity and distribution characteristics of imported malaria in Baise from 2009 to 2019, and we provide scientific basis for Baise to formulate appropriate prevention and control strategies and measures after realizing the goal of eliminating malaria. Methods The results of imported malaria surveillance from abroad in Baise from 2009 to 2019 were collected, analyzed and summarized. Results From 2009 to 2019, a total of 50 malaria cases were reported in Baise, of which 49 cases (98.00%) were blood positive, and 1 case (2.00%) was clinically diagnosed; The distribution of malaria species in blood test positive cases: 14 cases (28.57%) were vivax, 34 cases (69.39%) were falciparum, there was 1 case (2.04%) of ovum type malaria. No mixed infection and malariae malaria cases were found. The largest regional distribution of imported cases was in Longlin Various Nationalities Autonomous County (25 cases, 50.00%); all cases were male; except for a peak in January 2012, there was no significant seasonal distribution of cases overall; The average time from return to onset was 7.2 days, and the average time from onset to diagnosis was 7.8 days; 32 cases (64.00%) were reported by county CDC; Two cases of critical illness occurred in 2016 and 2018 respectively, and no fatal cases occurred. After the last local malaria case was reported in 2008, all malaria cases have been reported as imported malaria cases so far. In 2016, all cases reached the assessment criteria of malaria elimination at the district level in Guangxi, imported malaria cases have not resulted in secondary cases in the urban area of Baise. Conclusion The Malaria Control Strategy and comprehensive anti-malaria measures adopted in Baise are effective under the current situation of malaria control with no local cases. In the future, the measures of aetiological surveillance will be further implemented, health education and training for malaria control will be carried out, and the monitoring of the migrating population will be strengthened. 摘要:目的 分析2009—2019年百色市境外输人性疟疾疫情流行规律和分布特征,为百色市实现消除疟疾的目标 后制定适合的防控策略和措施提供科学依据。 方法 收集及整理2009—2019年百色市境外输人性疟疾疫情监测结果 并对数据进行分析和总结。 结果 2009—2019年百色市累计报告疟疾病例50例,其中49例为血检阳性病例 (98.00%),1例为临床诊断病例（2.00%)。血检阳性病例中虫种分布情况为：间日疟14例（28.57%),恶性疟34例 (69.39%),卵型疟1例(2.04%),无混合感染病例和三日疟病例的发现。输人性病例地区分布以隆林县最多(25例, 50.00%)性别全部为男性；除了 2012年1月份有一个高峰期外,总体上病例无明显的季节分布;从回国至发病平均时 间为7.2 d,从发病至确诊的平均时间为7.8 d;县级疾控中心报告32例（64.00%);危重症病例2例,分别于2016年及 2018年出现,无因重症而死亡的病例出现。2008年报告最后一例本地感染疟疾病例后,至今疟疾病例报告全部为境外 输人性,2016年达到广西壮族自治区消除疟疾考核评估的标准,输人性疟疾病例未在百色市辖区内引起继发性病例。 结论 百色市在没有本地病例的疟疾防治现状下采取的疟疾防控策略和综合抗疟措施有效。今后应进一步落实病原 学监测的措施,开展疟疾防治的健康教育宣传和培训以及加强对流动人口的监测。

To investigate the epidemiological characteristics and diagnosis of malaria cases in Nantong City from 2015 to 2020, so as to provide insights into the prevention of re-establishment of imported malaria and consolidation of malaria elimination achievements in the city. The epidemic data of malaria in Nantong City from 2015 to 2020 were captured from the National Notifiable Disease Report System, the Information Management System for Parasitic Disease Control and individual epidemiological survey reports of malaria cases. The malaria parasite species, source of infections, population distribution, temporal distribution, spatial distribution and diagnosis of imported malaria cases were descriptively and statistically analyzed. A total of 241 malaria cases were reported in Nantong City from 2015 to 2020, and all were overseas imported cases, including 191 cases with Plasmodium falciparum malaria (79.25%), 8 cases with P. vivax malaria (3.32%), 33 cases with P. ovale malaria (13.69%) and 9 cases with P. malaria malaria (3.73%). Overseas imported malaria cases acquired infections from 34 countries in Asia, Africa and Latin America, and 97.93% of the cases were infected in Africa, and 90.04% (217/241) were reported in Chongchuan District, Hai'an City and Haimen District. Imported malaria cases were aged from 20 to 68 years, and a median age of 45 (13) years, and 97.10% were male. The median duration between returning to China and malaria onset was 7 (9) days among all imported malaria cases, and the median duration from initial diagnosis to definitive diagnosis was 2 (2) days. There were 167 cases that were initially diagnosed as malaria, with a correct rate of 69.29%, and 53.53 (129/241) of malaria cases were diagnosed at city-level medical institutions and 41.49% (100/241) at county-level medical institutions. In addition, the proportion of malaria cases reported by city-level medical institutions increased from 39.62% in 2015 to 81.25% in 2020 (χ2 = 6.94, P < 0.01). The accuracy of initial malaria diagnosis requires to be improved in Nantong City. Malaria control knowledge should be specially given to migrant workers to shorten the duration of seeking medical care, and malaria training requires to be intensified among healthcare professionals to improve the diagnostic capability of imported malaria cases and the cure of severe P. falciparum malaria cases.

Malaria is the most common vector-borne parasitic infection causing significant human morbidity and mortality in nearly 90 tropical/sub-tropical countries worldwide. Significant differences exist in the incidence of malaria cases, dominant Plasmodium species, drug-resistant strains and mortality rates in different countries. Six Gulf Cooperation Council (GCC) countries (Bahrain, Kuwait, Qatar, Oman, Saudi Arabia and United Arab Emirates, UAE) in the Middle East region with similar climates, population demographics and economic prosperity are aiming to achieve malaria elimination. In this narrative review, all studies indexed in PubMed describing epidemiological characteristics of indigenous and imported malaria cases, vector control status and how malaria infections can be controlled to achieve malaria elimination in GCC countries were reviewed and discussed. These studies have shown that indigenous malaria cases are absent in Bahrain, Kuwait, Qatar and UAE and have progressively declined in Oman and Saudi Arabia. However, imported malaria cases continue to occur as GCC countries have large expatriate populations originating from malaria-endemic countries. Various malaria control and prevention strategies adopted by GCC countries including more stringent measures to reduce the likelihood of importing malaria cases by prior screening of newly arriving expatriates and vector elimination programs are likely to lead to malaria elimination in this region.

Objective To analyze the epidemiological characteristics of imported malaria in Zhejiang Province from 2007 to 2016, in order to provide a scientific basis for further improving the level of imported malaria control. Methods Data on malaria cases in Zhejiang Province from 2007 to 2016 were collected through the China Information System for Disease Control and Prevention (CISDCP). Descriptive epidemiological method was used to analyze the epidemiological characteristics of the imported malaria cases reported (including time distribution, regional distribution and population distribution). Results A total of 1 298 imported malaria cases were reported in Zhejiang Province from 2007 to 2016, including 988 falciparum malaria cases, 237 vivax malaria cases, 45 ovale malaria cases, 12 quartan malaria cases, 7 mixed infection and 9 unclassified cases. Most cases were 20 to 49 years old, accounting for 82.43% (1 070/1 298) of the total and the male to female ratio of the cases was 9.30: 1.00. The main groups of imported malaria cases were labor export staff, accounted for 46.92% (609/1 298); followed by business services, accounted for 38.91% (505/1 298). The cases mainly distributed in Jinhua, Hangzhou, Wenzhou, Lishui and Taizhou, which accounted for 75.96% (986/1 298) of the total. Totally 87.21% (1 132/1 298) of cases were imported from Africa, and 12.63% (164/1 298) were from Asian. Imported malaria cases were reported every month in the whole year without seasonal peaks. Conclusion Imported malaria cases in Zhejiang Province are given priority to with labor export and business services, so it is necessary to strengthen monitoring, diagnosis, and treatment of imported malaria cases among overseas workers and businessmen from the malaria prevalent areas in Africa and Asian countries. Key words: Malaria; Imported cases; Epidemiological characteristics

BackgroundFalciparum malaria is the most deadly among the four main types of human malaria. Although great success has been achieved since the launch of the National Malaria Control Programme in 1955, malaria remains a serious public health problem in China. This paper aimed to analyse the geographic distribution, demographic patterns and time trends of falciparum malaria in China.MethodsThe annual numbers of falciparum malaria cases during 1992–2003 and the individual case reports of each clinical falciparum malaria during 2004–2005 were extracted from communicable disease information systems in China Center for Diseases Control and Prevention. The annual number of cases and the annual incidence were mapped by matching them to corresponding province- and county-level administrative units in a geographic information system. The distribution of falciparum malaria by age, gender and origin of infection was analysed. Time-series analysis was conducted to investigate the relationship between the falciparum malaria in the endemic provinces and the imported falciparum malaria in non-endemic provinces.ResultsFalciparum malaria was endemic in two provinces of China during 2004–05. Imported malaria was reported in 26 non-endemic provinces. Annual incidence of falciparum malaria was mapped at county level in the two endemic provinces of China: Yunnan and Hainan. The sex ratio (male vs. female) for the number of cases in Yunnan was 1.6 in the children of 0–15 years and it reached 5.7 in the adults over 15 years of age. The number of malaria cases in Yunnan was positively correlated with the imported malaria of concurrent months in the non-endemic provinces.ConclusionThe endemic area of falciparum malaria in China has remained restricted to two provinces, Yunnan and Hainan. Stable transmission occurs in the bordering region of Yunnan and the hilly-forested south of Hainan. The age and gender distribution in the endemic area is characterized by the predominance of adult men cases. Imported falciparum malaria in the non-endemic area of China, affected mainly by the malaria transmission in Yunnan, has increased both spatially and temporally. Specific intervention measures targeted at the mobile population groups are warranted.