Sensitivity of Plasmodium falciparum to Antimalarial Drugs in Hainan Island, China

Pyronaridine and artesunate have been shown to be effective in falciparum malaria treatment. However, pyronaridine is rarely used in Hainan Island clinically, and artesunate is not widely used as a therapeutic agent. Instead, conventional antimalarial drugs, chloroquine and piperaquine, are used, explaining the emergence of chloroquine-resistant Plasmodium falciparum. In this article, we investigated the sensitivity of P. falciparum to antimalarial drugs used in Hainan Island for rational drug therapy. We performed in vivo (28 days) and in vitro tests to determine the sensitivity of P. falciparum to antimalarial drugs. Total 46 patients with falciparum malaria were treated with dihydroartemisinin/piperaquine phosphate (DUO-COTECXIN) and followed up for 28 day. The cure rate was 97.8%. The mean fever clearance time (22.5+/-10.6 hr) and the mean parasite clearance time (27.3+/-12.2 hr) showed no statistical significance with different genders, ages, temperatures, or parasite density (P>0.05). The resistance rates of chloroquine, piperaquine, pyronarididine, and artesunate detected in vitro were 71.9%, 40.6%, 12.5%, and 0%, respectively (Ppiperaquine>pyronarididine>artesunate. The inhibitory dose 50 (IC50) was 3.77x10(-6) mol/L, 2.09x10(-6) mol/L, 0.09x10(-6) mol/L, and 0.05x10(-6) mol/L, and the mean concentrations for complete inhibition (CIMC) of schizont formation were 5.60x10(-6) mol/L, 9.26x10(-6) mol/L, 0.55x10(-6) mol/L, and 0.07x10(-6) mol/L, respectively. Dihydroartemisinin showed a strong therapeutic effect against falciparum malaria with a low toxicity.

Sensitivity of Plasmodium falciparum to Antimalarial Drugs in Hainan Island, China

Pyronaridine and artesunate have been shown to be effective in falciparum malaria treatment. However, pyronaridine is rarely used in Hainan Island clinically, and artesunate is not widely used as a therapeutic agent. Instead, conventional antimalarial drugs, chloroquine and piperaquine, are used, explaining the emergence of chloroquine-resistant Plasmodium falciparum. In this article, we investigated the sensitivity of P. falciparum to antimalarial drugs used in Hainan Island for rational drug therapy. We performed in vivo (28 days) and in vitro tests to determine the sensitivity of P. falciparum to antimalarial drugs. Total 46 patients with falciparum malaria were treated with dihydroartemisinin/piperaquine phosphate (DUO-COTECXIN) and followed up for 28 day. The cure rate was 97.8%. The mean fever clearance time (22.5+/-10.6 hr) and the mean parasite clearance time (27.3+/-12.2 hr) showed no statistical significance with different genders, ages, temperatures, or parasite density (P>0.05). The resistance rates of chloroquine, piperaquine, pyronarididine, and artesunate detected in vitro were 71.9%, 40.6%, 12.5%, and 0%, respectively (Ppiperaquine>pyronarididine>artesunate. The inhibitory dose 50 (IC50) was 3.77x10(-6) mol/L, 2.09x10(-6) mol/L, 0.09x10(-6) mol/L, and 0.05x10(-6) mol/L, and the mean concentrations for complete inhibition (CIMC) of schizont formation were 5.60x10(-6) mol/L, 9.26x10(-6) mol/L, 0.55x10(-6) mol/L, and 0.07x10(-6) mol/L, respectively. Dihydroartemisinin showed a strong therapeutic effect against falciparum malaria with a low toxicity.

Study of universal salt iodization on child intellectual quotient development in Hainan province / 中国地方病学杂志

Objective To estimate the impact of universal salt iodization on child intelligence quotient (IQ) development in Hainan province. Methods In this is a cross-section study from September in 2008 to April in 2009,the observation group was historical iodine deficiency ward which includes 2 counties and 6 townships,and the control group was non-historical ward which includes 6 counties and 9 townships. Comparison of child IQ distribution according to different geographical housing position(plain,mountainous area,coast),age and sex based on the result of urine iodine examination and the IQ test of children between 8 and 10 years old. Results The median of urinary iodine of children in the observation group was 196.2μg/L which was 2.13 times of the urinary iodine median in the control group(91.9μg/L). The average IQ of children in the observation group was 94.7 which was 8.5 higher than the control group(86.2) ; IQ≤69 rate in this group was 7.7%(91/1179),and it was 8.9 percentage point lower than the control group[16.6%(253/1520)]; IQ≥ 110 rate of the group was 18.3%(216/1179),and it was 10.0 percentage point higher than the control group[8.3%(126/1520)]. The average IQ of children living in mountainous area(83.1) was the lowest in the control group. It was 3.5 and 5.1 lower than that of the children living in the plain(86.6) and coastal area(88.2) respectively; the IQ≤69 rate of children living in mountainous area [20.5%(91/443)]was the highest,and it was 3.8 and 7.1 percentage point higher than that of the children living in the plain [16.7% (89/533)]and coastal areas [13.4% (73/544)]respectively. The average IQ of children aged 8 (97.4) was similar to those aged 9(95.9) in the observation group which was 6.8 and 5.3 higher than that of the children aged 10(90.6) in the same group respectively; However,the average IQ of children aged 8,9 and 10 was close in the control group(86.8,86.3 and 85.6). The average IQ of boys(96.2) was 3.1 higher than that of the girls(93.1),and their IQ≤69 rate[6.3%(37/590)]was 2.9 percentage point lower than that of the girls[9.2% (54/589)]in the observation group. On the other hand,the average IQ(87.2) of boys was 2.1 higher than that of the girls(85.1),and IQ≤69 rate[14.5%(114/787)]was 4.5 percentage point lower than that of the girls [19.0%(139/733)]in the control group. The average IQ of children with different housing geographical position,age and sex in observation group was 5.0-12.4 higher than that of the control group; their IQ≤69 rate was 7.7-13.2 percentage point lower than that of the control group; their IQ≥110 rate was 5.6-13.0 percentage point higher than that of the control group. Conclusions Supplementing salt iodization can improve child intelligence. Supplementing iodine can increase the child IQ and reduce the child mental retardation.

Iodine deficiency disorders in high-risk areas of Hainan province from 2007 to 2009: an analysis of survey results / 中国地方病学杂志

Objective To know the prevalence of iodine deficiency disorders(IDD) and the implementation of control measures against the disorders in high-risk areas of Hainan province. Methods Typical sampling principle was used. Eight townships with lower coverage rate of iodized salt were chosen in IDD high-risk counties of Hainan. New cretinism cases were screened among children aged 10 years and under. Intelligence quotient (IQ)value, urinary iodine (UI) concentration and thyroid gland size (by palpation and B ultrasonic) were investigated in children aged 8 to 10 years and questionnaire was also carried out among students from grade 5 in elementary school. Edible salt and urine of women of childbearing age were collected to detect iodine levels, respectively,questionnaire was also carried out among the women of childbearing age. The UI was determined by As3-Ce4+ catalytic spectrophotometer, the salt iodine level was determined using self-quantitative kit. IQ values were measured by the Combined Raven Test in China (CRT-C2). Results Seventy-two townships were investigated in three consecutive years, 7937 children aged 8 to 10 years, 1797 women of childbearing age and 4128 students of grade 5 were included in the survey. One child was diagnosed as suspected new cretinism case. The coverage rate of iodized salt was increased from 44.6%(629/1411) in 2007 to 92.1%(1688/1832) in 2009. The goiter rate was dropped from 5.9% (269/4548), 6.0% (274/4548) in 2007 to 1.6% (24/1461), 0.1% (2/1461) in 2009 bypalpation, and by B-ultrasound, respectively, in children aged 8 to 10 years. The median urinary iodine(MUI) was found to be increased from 97.4 μg/L in 2007 to 165.0 μg/L in 2009, and the percentage of UI less than 50.0 μg/L, and 100.0 μg/L were dropped from 21.4%(973/4548), 51.2%(2329/4548) in 2007 to 7.5 %(110/1461), 23.4%(342/1461) in 2009, respectively. The MUI of women of childbearing age was found to be elevated from 73.7 μg/L in 2007 to 126.1 μg/L in 2009, and the value was also increased from 55.7 μg/L to 121.5 μg/L in pregnant women, but these values were still lower than 150.0 μg/L The pass rate of the questionnaire of IDD controlling among the students of grade 5 and the women of childbearing age was raised from 29.8% (446/1495) ,24.1% (179/742) in 2007 to 65.8%(732/1112), 72.1%(264/366) in 2009, respectively. The mean IQ of children was 90.4±16.0, and the percentage of IQ value less than 69 was 12.6% (1000/7937). Conclusions The diseased state of IDD has improved in the high-risk counties of disorders in Hainan province, but the pregnant women are still iodine deficient. Iodine supplimentation should be promoted among pregnant women.

Analysis on the relationship between malaria epidemics and NOAA-AVHRR NDVI in Hainan province / 中华流行病学杂志

<p><b>OBJECTIVE</b>To explore the relationship between malaria epidemics and NOAA-AVHRR NDVI.</p><p><b>METHODS</b>Data on malaria were collected in all 19 counties in Hainan province from Feb, 1995 to Jan, 1996. Values regarding normalized difference vegetation index (NDVI)-related indicators including mean and maximum values of NDVI, the area proportion of NDVI values of 145- and 145+, months with NDVI values of 135+, 140+, 145+, 150+ of these counties in this period were all extracted from NOAA-AVHRR images, using ERDAS8.5 software. The coefficients of correlation of malaria incidences and these NDVI-related indicator values were then calculated with SPSS 11.0.</p><p><b>RESULTS</b>The incidence of malaria showed positive correlations to mean and maximum values of NDVI, the area proportion of NDVI values of 145+ and months with NDVI values of 135+, 140+, 145+, 150+ respectively, but having negative correlation to the area of NDVI values of 145-. The malaria epidemic regions were in accordance with those regions that the NDVI values of 145+ were continuing for 9 months or more.</p><p><b>CONCLUSION</b>Malaria prevalence was associated with NOAA-AVHRR NDVI value which could be considered to be use for malaria surveillance in Hainan province.</p>

Study on the distribution of malaria in Hainan province through spatial local interpolation technique / 中华流行病学杂志

<p><b>OBJECTIVE</b>To explore the spatial distribution of malaria in Hainan province.</p><p><b>METHODS</b>Maps of spatial distribution on malaria incidence in Hainan province from 1995 to 1999 were produced, using a spatial local interpolation technique in the ArcGIS 8.1 software. Cross-validation techniques were used to evaluate the fitness of the distribution maps.</p><p><b>RESULTS</b>The spatial distribution of malaria in Hainan province from 1995 to 1999 showed that the incidence of malaria in the southern part of Hainan province were higher than that in the north. In the south, the incidence of malaria in east coastal areas were higher than that of other parts, especially in Wuzhi and Yingge mountains. The prediction error of the cross-validation indicated that the spatial distribution maps of malaria in Hainan had good fitness of malaria incidence of Hainan province.</p><p><b>CONCLUSION</b>Spatial local interpolation technique seemed to be promising in describing the spatial distribution of malaria.</p>