Imported and indigenous Plasmodium Vivax and Plasmodium Falciparum malaria in the Hubei Province of China, 2005-2019.

BACKGROUND: The Hubei Province in China reported its last indigenous malaria case in September 2012, but imported malaria cases, particularly those related to Plasmodium vivax and Plasmodium falciparum, threaten Hubei's malaria-free status. This study investigated the epidemiological changes in P. vivax and P. falciparum malaria in this province to provide scientific evidence for preventing malaria resurgence. METHODS: The prevalence, demographic characteristics, seasonal features, and geographical distribution of malaria were assessed using surveillance data and were compared across three stages: control stage (2005-2009) and elimination stages I (2010-2014) and II (2015-2019). RESULTS: In 2005-2019, 8483 malaria cases were reported, including 5599 indigenous P. vivax cases, 275 imported P. vivax cases, 866 imported P. falciparum cases, and 1743 other cases. Imported P. falciparum cases accounted for 0.07% of all cases reported in 2005, but increased to 78.81% in 2019. Most imported P. vivax and P. falciparum malaria occurred among males, aged 21-60 years, during elimination stages I and II. The number of regions affected by imported P. falciparum and P. vivax increased markedly in Hubei from the control stage to elimination stage II. Overall, 1125 imported P. vivax and P. falciparum cases were detected from 47 other nations. Eight imported cases were detected from other provinces in China. From the control stage to elimination stage II, the number of cases of malaria imported from African countries increased, and that of cases imported from Southeast Asian countries decreased. CONCLUSIONS: Although Hubei has achieved malaria elimination, it faces challenges in maintaining this status. Hence, imported malaria surveillance need to be strengthened to reduce the risk of malaria re-introduction.

Characteristics of imported Plasmodium ovale spp. and Plasmodium malariae in Hubei Province, China, 2014-2018.

BACKGROUND: There have been an increasing number of imported cases of malaria in Hubei Province in recent years. In particular, the number of cases of Plasmodium ovale spp. and Plasmodium malariae significantly increased, which resulted in increased risks during the malaria elimination phase. The purpose of this study was to acquire a better understanding of the epidemiological characteristics of P. ovale spp. and P. malariae imported to Hubei Province, China, so as to improve case management. METHODS: Data on all malaria cases from January 2014 to December 2018 in Hubei Province were extracted from the China national diseases surveillance information system (CNDSIS). This descriptive study was conducted to analyse the prevalence trends, latency periods, interval from onset of illness to diagnosis, and misdiagnosis of cases of P. ovale spp. and P. malariae malaria. RESULTS: During this period, 634 imported malaria cases were reported, of which 87 P. ovale spp. (61 P. ovale curtisi and 26 P. ovale wallikeri) and 18 P. malariae cases were confirmed. The latency periods of P. ovale spp., P. malariae, Plasmodium vivax, and Plasmodium falciparum differed significantly, whereas those of P. ovale curtisi and P. ovale wallikeri were no significant difference. The proportion of correct diagnosis of P. ovale spp. and P. malariae malaria cases were 48.3% and 44.4%, respectively, in the hospital or lower-level Centers for Disease Control and Prevention (CDC). In the Provincial Reference Laboratory, the sensitivity of microscopy and rapid diagnostic tests was 94.3% and 70.1%, respectively, for detecting P. ovale spp., and 88.9% and 38.9%, respectively, for detecting P. malariae. Overall, 97.7% (85/87) of P. ovale spp. cases and 94.4% (17/18) of P. malariae cases originated from Africa. CONCLUSION: The increase in the number of imported P. ovale spp. and P. malariae cases, long latency periods, and misdiagnosis pose a challenge to this region. Therefore, more attention should be paid to surveillance of imported cases of P. ovale spp. and P. malariae infection to reduce the burden of public health and potential risk of malaria.

Epidemiological characteristics of malaria from control to elimination in Hubei Province, China, 2005-2016.

BACKGROUND: Hubei 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. METHODS: Data 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. RESULTS: A 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. CONCLUSIONS: Hubei 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.

[Competition Results of Parasitic Disease Control Techniques among Technician in Hubei Province in 2015].

Objective: Objective To understand the qualification of technicians in parasitic disease control in Hubei Province by analyzing the rusults of technique competition in 2015. Methods: Provincial competitions on basic knowledge and on skills were conducted among 68 technicians in 17 cities （prefectures） in May 2015. The results were collected and analyzed with SPSS18.0 software. Scores were descriptively analyzed, and group comparisons were made by t-test and ANOVA. Results: The average score of the 68 competitors was 77.6, with a passing rate of 76.5%. In detail, the average scores of blood slide-making, Plasmodium detection, Kato-Katz slide-making and helminth egg detection were 9.3（passing rate, 98.5%）, 14.2 （32.4%）, 8.6 （98.53%） and 22.6 （27.9%） respectively. The average scores on theoretical knowledge and blood slide-making of female competitors were （84.5±17.3） and （9.4±0.4）, respectively, significantly higher than those of the males （70.7±21.1, 9.1±0.9 respectively） （P<0.05）. The scores of Plasmodium microscopy and egg microscopy were higher in competitors from counties［（16.3±8.0）, （25.8±12.0）］ than in those from cities/prefectures ［（12.5±6.5）, （20.0±10.8）］ （P<0.05）. In addition, the average scores on theoretical knowledge and egg dection were higher in competitors from districts with schistosomiasis control task ［（84.4±18.4）, （25.4±11.0）］ than in those from areas without schistosomiasis control task［（61.1±14.7）, （16.0±10.8）］（P<0.05）. There were no statistically significant differences in scores of various items among competitors of different ages and with professional ranks (P>0.05). Conclusion: There is a good overall performance among the professionals but an imbalance in detecting capability in different areas. The microscopic examination skill also needs to be improved.

Spatial, temporal, and spatiotemporal analysis of malaria in Hubei Province, China from 2004-2011.

BACKGROUND: Malaria remains a public health concern in Hubei Province despite the significant decrease in malaria incidence over the past decades. Furthermore, history reveals that malaria transmission is unstable and prone to local outbreaks in Hubei Province. Thus, understanding spatial, temporal, and spatiotemporal distribution of malaria is needed for the effective control and elimination of this disease in Hubei Province. METHODS: Annual malaria incidence at the county level was calculated using the malaria cases reported from 2004 to 2011 in Hubei Province. Geographical information system (GIS) and spatial scan statistic method were used to identify spatial clusters of malaria cases at the county level. Pure retrospective temporal analysis scanning was performed to detect the temporal clusters of malaria cases with high rates using the discrete Poisson model. The space-time cluster was detected with high rates through the retrospective space-time analysis scanning using the discrete Poisson model. RESULTS: The overall malaria incidence decreased to a low level from 2004 to 2011. The purely spatial cluster of malaria cases from 2004 to 2011 showed that the disease was not randomly distributed in the study area. A total of 11 high-risk counties were determined through Local Moran's I analysis from 2004 to 2011. The method of spatial scan statistics identified different 11 significant spatial clusters between 2004 and 2011. The space-time clustering analysis determined that the most likely cluster included 13 counties, and the time frame was from April 2004 to November 2007. CONCLUSIONS: The GIS application and scan statistical technique can provide means to detect spatial, temporal, and spatiotemporal distribution of malaria, as well as to identify malaria high-risk areas. This study could be helpful in prioritizing resource assignment in high-risk areas for future malaria control and elimination.

[Lymphatic filariasis in Hubei Province: from prevailing to elimination].

Lymphatic filariasis used to highly prevalent in 69 counties (cities) with 29 million people at the risk of infection in Hubei Province. There were 2 million people infected either by B. malayi or W. bancrofti that 1.6 million microfilaremia cases and 0.4 million chronic patients. The average rate of microfilaremia among population was 5.94%. Anopheles sinensis and Culex quinquefasciatus were the principal transmitting vectors. Since 1970s, with the strategy of taking elimination of infection source as a major focus, the average rate of the microfilaremia reduced to 0.048% with a village as the unit in 1988, and reached the standard of transmission interruption. With continuous surveillance for over a decade, the province reached the goal of filariasis elimination in 2001. This paper reviews the prevalence, control and elimination process of filariasis in Hubei Province since 1950s.

Epidemiology of Plasmodium falciparum Malaria and Risk Factors for Severe Disease in Hubei Province, China.

This study aimed to describe the epidemiology of Plasmodium falciparum malaria and identify risk factors for severe disease in Hubei Province, China, using a case-based survey of retrospective data from 2013 to 2018. From 2013 to 2018, a total of 763 imported malaria cases were reported in Hubei Province; 69.2% (528/763) cases were caused by P. falciparum species. The proportion of malaria caused by P. falciparum increased from 66.7% in 2013 to 74.0% in 2018 (χ2 = 21.378, P < 0.05). Plasmodium falciparum malaria was reported in 77 counties of Hubei Province. The majority of imported P. falciparum cases originated from Africa (98.9%, 522/528); 9.7% (51/528) of patients infected with P. falciparum developed severe malaria. Three deaths (case fatality rate: 0.6%) were related to imported P. falciparum malaria. Risk factors for severe malaria were being female (odds ratio [OR] = 3.593, 95% CI: 1.003-12.874), age ≥ 50 years (OR = 2.674, 95% CI: 1.269-5.634), > 3 days between symptom onset and diagnosis (OR = 2.383, 95% CI: 1.210-4.693), and the first-visit medical institution at the township level or lower (OR = 2.568, 95% CI: 1.344-4.908). Malaria prevention should be undertaken among high-risk groups, infection with P. falciparum should be detected early to prevent severe disease and death, and healthcare providers in health facilities at the township level should be trained on early recognition of malaria.

[Epidemiological analysis of malaria prevalence in Hubei Province in 2013].

OBJECTIVE: To explore the endemic situation of malaria in Hubei Province in 2013, so as to put forward effective elimination strategies and measures. METHODS: The data of malaria cases were searched from the Disease Reporting Information System of Chinese Center for Disease Control and Prevention and analyzed with the descriptive epidemiological method for the epidemiological characteristics of malaria in Hubei Province in 2013. RESULTS: A total of 129 malaria cases were reported in Hubei Province in 2013 with the incidence of 0.02/10,000, and all of them were imported cases, in which 86 cases with Plasmodium falciparum infection, 32 cases with P. vivax infection, 7 cases with P. ovale infection and 4 cases with P. malariae infection. The distribution of malaria cases was concentrated in Wuhan City (76 cases), Yichang City (10 cases), Xiangyang City (7 cases) and Huangshi City (6 cases), accounting for 76.74% of the total cases. There was no significant seasonal variation in the reporting time of the cases. Totally 99.22% of the cases were male, the age distribution concentrated mainly on 20-49 years. The occupation distribution concentrated mainly on the worker, farmer, cadre staff and migrant worker. The main original areas of the imported cases were Africa (111 cases, 86.05%) and Asia (17 cases, 13.18%). CONCLUSIONS: There is no local malaria cases reported in Hubei Province in 2013, however, the imported malaria cases are increased. Therefore, it is necessary to further strengthen the multi-sector collaboration of vector control, while the health education should be intensified especially in the key population.

[Epidemic situation and control strategy of imported malaria in Hubei Province from 2006 to 2011].

OBJECTIVE: To understand the characteristics of imported malaria in Hubei Province so as to provide the evidence for formulating the prevention and control strategy. METHODS: The data of all imported malaria cases from 2006-01 to 2011-07 were retrospectively analyzed, and at the same time, the imported malaria cases since 2010 were interviewed through telephone and the cases since 2011-05 were interviewed face to face. All data were analyzed with EpiInfo. RESULTS: There were 195 imported malaria cases from 2006-01-01 to 2011-07-07, and there was a rising trend but there was no obvious difference among seasons. The interval between the disease onset and diagnosis was shorter in high educated people than low educated people (chi2 = 10.93, P < 0.01) and in the severe cases than the slight cases (chi2 = 4.58, P < 0.05). The severe rates of malaria cases were 70.4% and 82.9% in the low educated group and the high educated group, respectively (chi2 = 7.02, P < 0.01). Non-condition regression analysis showed that there were three influence factors which affected severe malaria, including whether or not self-treatment instead of seeing doctor when being fever; whether or not having health education before going abroad; whether or not considering malaria of the initial diagnosis doctor. CONCLUSION: It is very important to strengthen the personnel abroad malaria health education, the malaria blood smear microscopic inspection in medical institutions, and the initial diagnosis doctor's awareness on malaria.