Malaria in Sri Lanka: Current knowledge on transmission and control

Malaria / Disease vectors / Waterborne diseases / Environmental effects / Public health / Economic impact / Social impact / Sri Lanka

Some Legal Problems of State Trading in Southeast Asia

State trading-trade conducted internationally by a state or public agency-has become a feature of the mixed economies of southeast Asia. With the growing importance of economic planning and the increase of state intervention (often tantamount to absolute control)in areas of the economy of individual southeast Asian countries, there has been an expansion of international trading functions by states or public agencies. Much of this trade is conducted at a state to state level, i.e., on a bilateral basis. This kind of infrastructure is attributable in part to the fact that the Communist bloc countries generally either have no place for the private trader or else regard him with particular caution. Ceylon\u27s bilateral trade is a result of its market instability and its search for economic independence. Al-though its dealings are largely with Communist China, it is unlikely that Ceylon will make a permanent shift out of world markets in favor of total bilateral trade. India\u27s trade with the Soviet bloc, on the other hand, is motivated largely by the desire to display economic and political neutrality by opening its gates to trade with all countries. In the case of Burma, expansion of markets for rice at a time when it was having difficulty selling in its traditional markets was,perhaps, the crucial factor. The situation of Indonesia, whose position in the world market for primary products was particularly strong, is more difficult to explain. It is possible that the Sino-Soviet bloc found in Indonesia a useful source for much needed materials and offered her especially attractive terms for her industrial development in return for those materials; in addition, a good deal of political sympathy for Communist China within Indonesia led to a certain acquiescence in bilateralism, even though the nature of the Indonesian economy did not warrant any such predisposition

Small irrigation tanks as a source of malaria mosquito vectors: a study in north-central Sri Lanka

Watersheds / Tank irrigation / Rehabilitation / Malaria / Waterborne diseases / Disease vectors / Sri Lanka / Yan Oya

Malaria and land use: a spatial and temporal risk analysis in Southern Sri Lanka

Malaria / Waterborne diseases / Disease vectors / Land use / Water use / GIS / Statistical analysis / Risks / Mapping / Public health / Sri Lanka / Uda Walawe / Thanamalvila / Embilipitiya

Temporal correlation between malaria and rainfall in Sri Lanka

<p>Abstract</p> <p>Background</p> <p>Rainfall data have potential use for malaria prediction. However, the relationship between rainfall and the number of malaria cases is indirect and complex.</p> <p>Methods</p> <p>The statistical relationships between monthly malaria case count data series and monthly mean rainfall series (extracted from interpolated station data) over the period 1972 – 2005 in districts in Sri Lanka was explored in four analyses: cross-correlation; cross-correlation with pre-whitening; inter-annual; and seasonal inter-annual regression.</p> <p>Results</p> <p>For most districts, strong positive correlations were found for malaria time series lagging zero to three months behind rainfall, and negative correlations were found for malaria time series lagging four to nine months behind rainfall. However, analysis with pre-whitening showed that most of these correlations were spurious. Only for a few districts, weak positive (at lags zero and one) or weak negative (at lags two to six) correlations were found in pre-whitened series. Inter-annual analysis showed strong negative correlations between malaria and rainfall for a group of districts in the centre-west of the country. Seasonal inter-annual analysis showed that the effect of rainfall on malaria varied according to the season and geography.</p> <p>Conclusion</p> <p>Seasonally varying effects of rainfall on malaria case counts may explain weak overall cross-correlations found in pre-whitened series, and should be taken into account in malaria predictive models making use of rainfall as a covariate.</p

Epochal changes in the association between malaria epidemics and El Niño in Sri Lanka

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Pre-elimination stage of malaria in Sri Lanka: assessing the level of hidden parasites in the population

<p>Abstract</p> <p>Background</p> <p>With the dramatic drop in the transmission of malaria in Sri Lanka in recent years, the country entered the malaria pre-elimination stage in 2008. Assessing the community prevalence of hidden malaria parasites following several years of extremely low transmission is central to the process of complete elimination. The existence of a parasite reservoir in a population free from clinical manifestations, would influence the strategy for surveillance and control towards complete elimination.</p> <p>Methods</p> <p>The prevalence of hidden parasite reservoirs in two historically malaria endemic districts, Anuradhapura and Kurunegala, previously considered as high malaria transmission areas in Sri Lanka, where peaks of transmission follow the rainy seasons was assessed. Blood samples of non-febrile individuals aged five to 55 years were collected from randomly selected areas in the two districts at community level and a questionnaire was used to collect demographic information and movement of the participants. A simple, highly sensitive nested PCR was carried out to detect both <it>Plasmodium falciparum </it>and <it>Plasmodium vivax</it>, simultaneously.</p> <p>Results</p> <p>In total, 3,023 individuals from 101 villages participated from both districts comprising mostly adults between the ages 19-55 years. Out of these, only about 1.4% of them (n = 19) could recall having had malaria during the past five years. Analysis of a subset of samples (n = 1322) from the two districts using PCR showed that none of the participants had hidden parasites.</p> <p>Discussion</p> <p>A reservoir of hidden parasites is unlikely to be a major concern or a barrier to the ongoing malaria elimination efforts in Sri Lanka. However, as very low numbers of indigenous cases are still recorded, an island-wide assessment and in particular, continued alertness and follow up action are still needed. The findings of this study indicate that any future assessments should be based on an adaptive sampling approach, involving prompt sampling of all subjects within a specified radius, whenever a malaria case is identified in a given focus.</p

Achieving Operational Hydrologic Monitoring of Mosquitoborne Disease

West Nile virus transmission in Florida can be monitored by using modeled hydrology