Effect of land use and land cover modification on distribution of anopheline larval habitats in Meghalaya, India.

BACKGROUND & OBJECTIVES: The Meghalaya region had been considered free of malaria, but recently malaria cases in the foothills and valley areas raised concern that malaria transmission at high elevations may be increasing. This increase is associated with land use and land cover (LULC) changes. This LULC directly modifies larval habitats and affect the anopheline larval distribution patterns. METHODS: In this survey, effects of LULC changes on the distribution of anopheline larval habitats in Meghalaya over a three year period (April 2008 to March 2011) was observed. Mosquito density and diversity of neighbouring four villages located along natural swamps (less disturbed) were compared with 16 villages located near disturbed area (cultivated area, urban area, pastures land area and national highway area). RESULTS: The association between LULC type and occurrence of anopheline larvae was statistically significant. The distribution of anopheline positive habitats varied significantly between seasons. The mean density of Anopheles was significantly higher in urban area in all the seasons, but higher in farm land and pasture land areas only in rainy and post-rainy seasons. The six most common species collected were Anopheles maculatus (19.2%), An. vagus (13.7%), An. annularis (9.1%), An. philippinensis (8.1%), An. barbirostris (5.1%) and An. minimus (4.6%). LULC changes occurred mainly in valleys and National Highway Development Programme Phase III site. Overall, open forest area, farm land area and national highway development project phase area were observed to increase by 2.9, 1.7, and 2.1% respectively. INTERPRETATION AND CONCLUSION: Our results indicate that LULC changes in the study area were favourable to Anopheles larval development, increasing the risk of the spread of malaria vector habitats and malaria transmission to non-malarious regions of Meghalaya.

Hypoglycemic effects of Potentilla fulgens L in normal and alloxan-induced diabetic mice.

Tap roots of Potentilla fulgens L. traditionally chewed along with betel nut (Areca catechu) and betel leaves (Piper betel), are commonly used by local practitioners for various types of ailments. The crude methanolic extract of the roots was tested for its effects in normoglycemic and alloxan-induced diabetic mice. Hypoglycemic activity was observed to be dose- and time- dependent. The extracts reduced blood glucose level 2 h following administration in both normal and alloxan-induced diabetic mice. In alloxan-induced diabetic mice blood glucose was markedly reduced by 63%, while in normal mice a 31% reduction was observed 24 h after the effective dose of extract was administered. Further, in the diabetic mice a prolonged anti-hyperglycemic action was observed where glucose levels was, found to be significantly low (79%) when compared with control even on the third day. Glucose tolerance was also improved in both normal and diabetic mice. The results were compared against those of insulin, glibenclamide, metformin, and the probable mechanism of action is discussed.

Intake of ²³8U and ²³²Th through the consumption of foodstuffs by tribal populations practicing slash and burn agriculture in an extremely high rainfall area.

The concentration of naturally occurring radionuclides ²³²Th, ²³8U was determined using Instrumental Neutron Activation Analysis (INAA) in different food groups namely cereals, vegetables, leafy vegetables, roots and tubers cultivated and consumed by tribal population residing around the proposed uranium mine. The study area is a part of rural area K. P. Mawthabah (Domiasiat) in the west Khasi Hills District of Meghalaya, India located in the tropical region of high rainfall that remains steeped in tribal tradition without much outside influence. Agriculture by Jhum (slash and burn) cultivation and animal husbandry are the main occupation of the tribal populations. A total of 89 samples from locally grown food products were analyzed. The concentration of ²³8U and ²³²Th in the soil of the study area was found to vary 1.6-15.5 and 2.0-5.0 times respectively to the average mean value observed in India. The estimated daily dietary intake of ²³8U and ²³²Th were 2.0 µg d⁻¹ (25 mBq d⁻¹) and 3.4 µg d⁻¹ (14 mBq d⁻¹) is comparable with reported range 0.5-5.0 µg d⁻¹ and 0.15-3.5 µg d⁻¹ respectively for the Asian population.