Effectiveness of abate 1sg larvicide in dengue prevention in rachgia city, KienGiang province

Nội dung text: Effectiveness of abate 1sg larvicide in dengue prevention in rachgia city, KienGiang province

1. Journal of military pharmaco-medicine n o2-2018 EFFECTIVENESS OF ABATE 1SG LARVICIDE IN DENGUE PREVENTION IN RACHGIA CITY, KIENGIANG PROVINCE Bui Khanh Toan*; Nguyen Huy Nga* Nguyen Xuan Truong*; Nguyen Van Chuyen** SUMMARY Objectives: To assess the effectiveness of ABATE 1SG larvicide in dengue prevention, in two wards of Rachgia city, Kiengiang province. Method: Intervention study in community, with an intervention group and a control group to assess the effectiveness of ABATE 1SG larvicide application to water storage containers (excluding drinking water) in Rachgia city, Kiengiang province. Result: The effectiveness of ABATE SG larvicide was 100% after 24 hours; 100% after a month and maintains a high efficiency after 3 months (98.68%). The effectiveness of larvicide ABATE 1SG has been proven more than 3 months even in the outdoor condition of the water storage containers whose levels are often changed due to the weather. Conclusion: ABATE 1SG kills completely Aedes larvae in water storage containers after 24 hours and could eliminate Aedes larvae during the next 3 months in the outdoor conditions of the water storage containers. * Keywords: Aedes; Larvae; Mosquitoes; ABATE 1SG; Rachgia city, Kiengiang province. INTRODUCTION ingredient temephos and most trusted Every year, about 100 million cases of temephos larvicide. It is a non-systemic dengue haemorrhagic fever are reported organophosphorus insecticide, mainly used around the world. Children under 15-year- as a larvicide to control vector-born diseases by mosquitoes, such as dengue and old represent more than 90% of the cases; malaria. According to the World Health and dengue fever causes 5% of their Organization, ABATE 1SG is recommended deaths. The disease mainly circulates in to use as a kind of larvicide in public tropical and subtropical regions, especially health programs, which can be also used in Southeast Asia and the Pacific, including for drinking water storage containers [3]. Vietnam [1]. Although scientific researchs In Vietnam, ABATE 1SG has been focus on the disease over the past many approved by Ministry of Health (MOH) for years, to date, no vaccines have been insecticide use in non-drinking water storage developed and there is no specific containers [4]. In 2003, National Institute treatment for dengue. Therefore, the of Hygiene and Epidemiology conducted vector is nowaday the most effective the study on the effectiveness of ABATE measure to control dengue fever [2]. 1SG application to larvae in laboratory. Abate 1SG (a trading name is The results showed that ABATE 1SG ABATE 1SG) is based on the active killed 100% of larvae in laboratory [5]. ** Ministry of Health *** Military Medical University Corresponding author: Bui Khanh Toan (khanhtoandr@gmail.com) Date received: 31/07/2017 Date accepted: 22/01/2018 99
2. Journal of military pharmaco-medicine n o2-2018 Aedes mosquitoes is the main vector - The selected water storage containers of dengue in Vietnam. Mosquitoes lay eggs requires these criteria: not for drinking in man-made water storage containers. Its water; not for useful aquatic or marine eggs grow into larvae and hatch into products; no natural biological agents mosquitoes. The removal of larvae can which are resistant to larvae, such as actually eliminate mosquitoes. In recent mesocyclops; water storage containers years, there have been many measures should be fairly stable in terms of location to remove larvae such as organizing and storage volume, ensuring traceability environmental sanitation campaigns, throughout the study. collecting waste, using biological agents, 2. Study design. insecticides ... but the use of ABATE 1SG Intervention study in community, under larvicide has not yet been realized widely an intervention group and a control group, in Vietnam for dengue prevention, especially pre-post comparison of the effectiveness in the South where rainy season lasts of the intervention. months and people have the habit to use water storage containers. * Study location: Dengue haemorrhagic fever occurs The selected location are two wards in mainly in the South of Vietnam where Rachgia city, Kiengiang province: Anhoa Kiengiang is one of the provinces with the ward (intervention group) and Anbinh highest dengue cases. Assessing the ward (control group). The communities in effectiveness of ABATE 1SG larvicide in two wards have similar habitat conditions. dengue vector control in the field in * Study time: Rachgia city, Kiengiang province needs to The study was conducted from April have the effective measure in dengue 2014 to November 2014. prevention and therefore, to encourage - Select study location and intervention community to use ABATE 1SG widely in arrangment: from April to August 2014. the South of Vietnam as well as in the - Investigation before application; whole country. This study aimed: To assess application of ABATE 1SG; investigation the effectiveness of ABATE 1SG larvicide in the field in Rachgia city, Kiengiang 24 hours, 1 month and 3 months after province, as well as its long-term effect. application: from August to November 2014. * Sample size and sampling method: METHODS - Sample units are water storage 1. Study target. containers regardless of types and volumes. - Water storage containers and larvae Sample size is calculated by the formula of Aedes in household water storage for the sample size of the intervention containers. study: 100
3. Journal of military pharmaco-medicine n o2-2018 Z1 - α/2 .p.q.f p1 - p 2 n = -------------------- D2 EI = ------------ x 100 p1 p1 + p2 among them: p = ----------- p1 = CI before application. 2 p = CI after application. q = 1-p 2 2 - Indicator formulas and investigation f = (Z α + Z β) /2 methods were followed by Ministry of D = [p1 - p2] Health Procedures [6, 7]. n: Number of water storage containers applied in the study. * Materials and application techniques: p: Container index (CI). - Chemicals and dosage: p1: The rate before intervention + ABATE 1SG: contains temephos 1%, (approx. 80%). product of BASF AG company (Federal p2: The rate after intervention, is expected Republic of Germany). The license by to be 10%. Ministry of Health VNDP-HC-194-08-09, With a confidence interval is 95% and WHO/SIF/40.R1/1999 quality standards. a sample effect is 95%, the minimum + Dosage: 1 g ABATE 1SG/10 liters of sample size of each group is 200. water. * Indicators: + ABATE 1SG is packed in a plastic jar - Indicators of larvae: House index (HI), with a weight of 100 g. container index (CI), Breteau index (BI). - Application techniques: followed the - The efficiency index (EI): manufacturer’s catalogue. RESULTS AND DISCUSSION 1. Assessment after application. Table 1: CI before and after application. Intervention group Control group CI (n = 348) (n = 345) Comparison Number % Number % Before application 290 83.3 293 84.9 p > 0.05 After 24 hours 0 0.0 293 84.9 p < 0.01 After 1 month 0 0.0 274 79.4 p < 0.01 After 3 months 4 1.1 250 72.5 p < 0.01 The results of the investigation before was 83.3%, in the control group, it was 84.9%. intervention in Anhoa showed that in the There was no difference in the percentage intervention group, the percentage of water of water storage containers with Ae. aegypti storage containers with Ae. aegypti larvae larvae between 2 groups (p > 0.05). 101
4. Journal of military pharmaco-medicine n o2-2018 After 24 hours, investigation of larvae the water storage containers with larvae showed that the percentage of water in the control group and in the intervention storage containers with larvae in the group one, which was statistically significant intervention group decreased from 83.3% (p < 0.01). to 0.0%. In the control group, the percentage The results of the larval investigation of water storage containers with larvae did one month after application in Anhoa ward not decrease in comparison with before indicated that in the intervention group, all application. Also, during the application of the water storage containers did have day in the intervention group, in the control no larvae, whereas in the control group, area of Anbinh ward, health authority the percentage of water storage containers implemented an environmental sanitation with larvae was 79.4%. The difference campaign, that is killing larvae on a large between the intervention and control groups scale with a participation of many health was statistically significant (p < 0.01). workers and collaborators. Although health workers and collaborators have been 3 months after application, in Anhoa informed about the intervention study, and ward - the intervention group, larvae return the water storage containers in the control to only 1.1% of its water storage containers, group have been marked, some of the water while in the control group, the percentage storage containers were still removed of water storage containers with larvae larvae by the collaborators and health was 72.5%. The difference between the workers if possible. However, there was a intervention and the control groups was big difference in the percentage between statistically significant (p < 0.01). 2. Assessment of EI. Table 2: Comparison of EI between control and intervention groups. Control group (n = 345) Intervention group (n = 348) Time of assessment CI EI (%) CI EI (%) Before application 84.9 - 83.3 - 24 hours after application 84.9 0 0 100 1 month after application 79.4 6.48 0 100 3 months after application 72.5 14.61 1.1 98.68 Assessing EI in the intervention group, it reached 100% after 24 hours. It maintained 100% after a month and after 3 months, the EI was staying around 98.68%. In the control group, despite an addition of the campaign of environmental sanitation against larvae, the EI was only 6.48% after a month and 14.61% after 3 months. This result is also consistent with a study by National Institute of Hygiene and Epidemiology (2003): ABATE 1SG with a dose of 1 g/10 liters, which removes 100% of larvae of Aedes 1, 2, 3, 4 days of age [5]. 102
5. Journal of military pharmaco-medicine n o2-2018 3. Assessment of HI and BI. Table 3: Comparison of HI. HI Intervention group Control group Comparison Before application 83.49 86.89 p > 0.05 24 hours after application 0 86.89 p < 0.01 1 month after application 0 71.84 p < 0.01 3 months after application 1.89 60.68 p < 0.01 Before application, comparing HI respectively. The differences in HI between between two groups, there was no the two groups at two different timemarks difference between the intervention group were both statistically significant (p < 0.01). and the control group (p > 0.05). After 3 months, the HI in the But after the application, HI showed a intervention group was still very low marked difference between the two groups. (1.89). On the other hand, in the control In the intervention group, after 24 hours, group, the HI was 60.68. There was a HI decreased to zero and remained zero big difference in HI between these two after a month. Meanwhile, in the control groups and the difference was statistically group, HI values were 86.89 and 71.84, significant (p < 0.01). Table 4: Comparison of BI. BI Intervention group Control group Comparison Before application 136.79 142.23 p > 0.05 24 hours after application 0 142.23 p < 0.01 1 month after application 0 133.01 p < 0.01 3 months after application 1.89 121.36 p < 0.01 Comparison of the BI in the table and after a month. After 3 months, the BI above shows that between the two groups, was low. Meanwhile, in the control group, before application, the BI between the the BIs were consistently high in all three intervention and control groups was not investigations, 142.23, 133.01, and 121.36, significantly different (p > 0.05). respectively. The differences in BI After application, in the intervention between the intervention and control group, the BI was reduced to zero at the groups in all three investigations were time of the investigation after 24 hours statistically significant (p < 0.01). 103
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