Short report: unmanned aerial vehicle for wide area larvicide spraying (WALS) using Vectobac® WG at Kota Kinabalu, Sabah.

INTRODUCTION: Given the stagnating progress in the fight against dengue in Kota Kinabalu, there is an urgent need to use other strategies to complement the existing vector control, focusing on larviciding. Unmanned aerial vehicle (UAV) technology has been used in vector control programs in many countries. The aim of this study was to determine the feasibility of using UAVs for larviciding to control Aedes mosquitoes in urban areas. METHODOLOGY: The Hexarotor Agro Drone (Polardrone Sdn Bhd, Malaysia) was used to carry out larviciding using Vectobac® manufactured by Valent BioSciences LLC, Libertyville, USA. The drone flew at a height of 10 feet and at a speed of 5 m/s. A total of 32 items with 10 larvae in each item were placed to test the effectiveness of larviciding using UAV. RESULTS: Out of 32 items used, 4 containers had a 100% larva mortality (13.3% mortality). The drone was not able to reach the designated spraying route that had been pre-programmed. This was due to interference with the electromagnetic waves emitted from the home satellite dishes, that were in front of the houses along the route. CONCLUSIONS: This trial showed that UAVs will be more suitable for use in larviciding in an open area without electromagnetic disturbances from electric house poles and satellite TV dishes that are commonly present in urban areas.

Full-length sequence analysis of chloroquine resistance transporter gene in Plasmodium falciparum isolates from Sabah, Malaysia.

Chloroquine resistance (CQR) in falciparum malaria was identified to be associated with several mutations in the chloroquine resistance transporter gene (pfcrt) that encodes the transmembrane transporter in digestive vacuole membrane of the parasite. This study aimed to investigate the point mutations across the full-length pfcrt in Plasmodium falciparum isolates in Sabah, Malaysia. A total of 31 P. falciparum positive samples collected from Keningau, Kota Kinabalu, and Kudat, Sabah, were analyzed. pfcrt was PCR amplified and cloned prior to sequence analysis. This study showed that all the previously described 10 point mutations associated with CQR at codons 72, 74, 75, 76, 97, 220, 271, 326, 356, and 371 were found with different prevalence. Besides, two novel point mutations, I166V and H273N, were identified with 22.5% and 19.3%, respectively. Three haplotypes, namely, CVMNK (29%), CVIET (3.2%), and SVMNT (67.7%), were identified. High prevalence of SVMNT among P. falciparum isolates from Sabah showed that these isolates are closer to the P. falciparum isolates from Papua New Guinea rather than to the more proximal Southeast Asian CVIET haplotype. Full-length analysis of pfcrt showed that chloroquine resistant P. falciparum in Sabah is still prevalent despite the withdrawal of chloroquine usage since 1979.

Iron status and dietary iron intake of adolescents from a rural community in Sabah, Malaysia.

Iron deficiency anaemia (IDA) is the most prevalent micronutrient deficiency in the world affecting the general health and wellbeing of millions. In Malaysia, moderately high prevalences of anaemia have been reported amongst infants, young children and women of childbearing age. Data is scant for the adolescents. This study was undertaken to assess the iron status and dietary intake of 165 adolescents, comprising 74 male and 91 female subjects, aged 12 to 19 years, from the rural communities in Tuaran District of Sabah, Malaysia. Convenience sampling was used for the selection of study subjects. Multiple iron status indicators namely, serum ferritin (SF), transferrin saturation (TS), mean corpuscular volume (MCV) and haemoglobin (Hb) were determined for the study. The mean age of the subjects was 15.2 +/-2.1 years. While the majority of the subjects (77.6%) had normal body mass index (BMI) values, 17.6% were underweight and 4.8% overweight. About 35% to 40% of the subjects showed deficient values for haematocrit, serum ferritin, serum iron, mean corpuscular haemoglobin (MCH), mean corpuscular volume (MCV) and transferrin saturation (TS), and 20% were anaemic (Hb <12 g/L). Using the multiple criteria of iron status indicators, the prevalence of iron depletion, iron deficiency and IDA in the male and female adolescents were 5.4% vs. 6.6%, 18.9% vs. 26.4% and 5.4% vs. 26.4%, respectively. Iron deficiency anaemia (85.0%) contributed largely to the prevalence of anaemia. The dietary iron intake of the adolescents was unsatisfactory, with approximately 98% of subjects failing to meet the Malaysian RDA level. Almost all the female subjects (91%) had dietary iron intake below two-thirds of the RDA level compared with a much smaller proportion for the male adolescents (68%). The prevalence of IDA in the present study population, especially in the female adolescents, appears to be a significant public health problem. Priority should therefore be given to the eradication of iron deficiency in adolescents from low-income areas by dietary modification and micronutrient supplementation amongst female adolescents.