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Objective: To understand the malaria epidemiological characteristics of Shandong Province in 2017, so as to provide the evidences for formulating targeted prevention and control strategy and measures., Methods: The data of malaria cases of Shandong Province in 2017 were collected from the Information Management System for Infectious Diseases Report and Information Management System for Parasitic Diseases Control and Prevention. The epidemiological characteristics of malaria situation and the diagnosis and treatment of malaria cases were analyzed., Results: There were 209 malaria cases reported in 2017, all of them were imported cases, and 205 cases (98.09%) were imported from African countries. Among them, 155 cases (74.16%) were falciparum malaria cases. Totally 16 cities had cases reported in 2017, and 154 cases (73.68%) were reported in 6 cities (Yantai, Jining, Weihai, Dezhou, Qingdao, and Tai'an). The malaria cases distributed in 17 cities, and there were 110 cases distributed in 4 cities, namely Yantai, Tai'an, Weihai, and Qingdao, which accounted for 56.41% of the total cases in Shandong Province. Both the median time from onset to seeing a doctor and the median time from seeing a doctor to being diagnosed were one day. Totally 12.92% of the cases went to visit a doctor 7 days later after they had symptoms and 10.53% of the cases were diagnosed 7 days later after the first visit to a doctor., Conclusions: At present, the prevention and control of the imported malaria is the focus of malaria control in Shandong Province. According to the central tendency of the malaria situation, the health education and propaganda among the high risk groups and the training on the diagnosis and treatment among medical workers should be strengthened, so as to prevent the risk of reappearance of local cases in the past malaria endemic regions, and to ensure the goal of malaria elimination been achieved on schedule.

Objective: To analyze the genotypes and homology of MSP-1 and CSP gene of Plasmodium vivax in Shandong Province, so as to provide the evidence for case traceability., Methods: A total of 12 blood samples were collected from P. vivax -infected cases in Shandong Province in 2011. Parasite genomic DNA was extracted. Primers were designed according to MSP-1 and CSP gene sequences of P. vivax . Then Nested PCR, enzyme digestion, sequencing and sequence alignment, and homologous analysis were performed., Results: The MSP-1 gene of all the 12 samples from P. vivax -infected cases were detected with a 470 bp PCR amplification band, and 350 bp and 120 bp enzyme digestion fragments, which were identified as type Sal-1. An analysis of phylogenetic tree of MSP-1 gene showed that the sequences of 9 indigenous case samples in Shandong Province were located in the same branch, one case sample infected from India was located in the same branch with India strains. All the 12 P. vivax -infected samples covered GDRA (D/A) GQPA sequences in CSP gene, which were identified as type PV-Ⅰ. Of the CSP gene among 12 P. vivax -infected samples, 10 samples of indigenous case in Shandong Province and one sample of the case infected in Guangdong Province were detected with both 560-840 bp and 150-230 bp PCR amplification bands, which were identified as temperate zone family strain of type PV-Ⅰ. However, one sample from the case infected in India was detected only with a 560-840 bp band, which was identified as tropical zone family strain of PV-Ⅰ. An analysis of phylogenetic tree of CSP gene showed that the sequences of 10 samples from the indigenous cases in Shandong Province and one sample from the case infected in Guangdong Province were located in the same branch, one sample from the case infected in India was located in the same branch with India and Indonesia strains., Conclusions: Of all the indigenous isolates in Shandong Province, MSP-1 gene is genotyped type Sal-1, CSP gene is genotyped temperate zone family strain of type PV-Ⅰ, with a high homology found among the indigenous isolates.

Objective: To explore the association between malaria epidemic situation and some natural and social factors in high-incidence areas of Shandong Province, so as to provide evidences for malaria elimination in these areas., Methods: Twenty towns of 10 counties (cities, districts,) in the high incidence areas of malaria in Shandong Province were selected as the study sites, and the residents in the study sites were investigated by questionnaires with one household as a unit, so as to understand the related natural and social factors. In addition, the malaria epidemic data in the study sites from 2006 to 2010 were collected, and the correlation between these factors and the epidemic situation of malaria was analyzed by Spearman rank correlation and multiple stepwise regression., Results: The square root of malaria incidence rate ( Y ) was negatively related to the rate of households using insecticide ( X 3 ), and the rate of households using screen doors and windows ( X 4 ) (both P < 0.05), but was positively related to the rate of housing surrounding water environment and exposure ratio ( X 6 ) (both P < 0.05). The regression equation established was Y = 0.032 X 5 + 0.048 X 6 -0.495, R 2 = 0.973., Conclusions: Malaria incidence is obviously associated with some natural and social factors. The measures such as clearing the breeding place of mosquito, protecting the exposure population at nightfall, as well as using door-window screen and repellents correctly, can effectively control malaria.