It is good to get more input from others, but some one has to come foreward no? Regarding studies on efficacy of source reduction I shall try to locate some and make it available here. About the efficacy of chemical methods, the statements in WHO's annual report will suffice. If we are looking for a study on efficacy of GEM method, we will not find any since no expert would have ever dreamt of it. Any one would consider it safer to take up a study on an accepted theory/methodology and enjoy the benefits out of it rather than burn the finger on a new theory propounded by an unknown idiot. Probably time is not yet ripe for it (GEM method).
It is indubitable that water is an essential factor in the progress of life cycle of mosquito. Wthout water the cycle cannot continue, it will break. None can neglect or reduce the significance of water in mosquitoe's life-cycle. I am convinced that water has been purposely introduced by the creator in the life cycle to act as a powerful limiting factor to counter act the almost unlimited freedom it enjoys in its adult phase and also to compensate the ill effects of its ability to produce 100 to 300 eggs during its short span (4 to 6 weeks) of its adult life.
You are 100% right on your statement that deserts are not the place for mosquitoes. Without water & warm blooded creatures (for females) they cannot continue their life cycle (males' feeding is not a problem). You are also right that availability of water is an important limiting factor in the growth of mosquito population.
IF we can make water unavailable to mosquito, we can certainly limit its population. No doubt about that. Doubt is about HOW do we accomplish it? Can we realise a desert like environment in an inhabited place? Will it be affordable? Will it be sustainable? Will it be environmentally acceptable?
I feel the answers to all these questions are in the negative - an emphatic NO. If the answer is +ve what prevents any one from doing that and saving millions of lives every year.
----------------------------------------------------------------------------------------------------------------
I have some graphs of the Malaris incidence of some states of Indian Union. They were prepared a decade ago for easy comparability. The time period considered is 1961 to 1994. First diagram is of states Keralam, Tamil Naadu & Orissa. Second is Keralam & Orissa. Third is Keralam & Haryana.
Keralam, Tamil Naadu & Karnataka are neighbouring states of southern peninsula of India sharing common boarders. Keralam has forty four (44) rivers, several lakes & ponds, millions of drinking water wells, numerous perennial streams, large areas of paddy fields that retain water for several months and areawise it is less than one-third of other states. Due to the comfortable climate & vegetation (implying wetness) national as well as foreign tourists renamed Keralam as God's own country.
Tamil Naadu is a much hotter & more dry state compared to Keralam. Karnataka also is similar. With these things in mind if we look at the number of Malaria cases of these states over the three (3) decades one would be tempted (or forced?) to think that more than water or wetness something else is a more important limitins factor. I feel it is ambient temperature.
This does not imply that water is insignificant in mosquito's life-cycle. What is meant is that along with water there are other significant or more significant limiting factors that we should not over-look.
------------------------------------------------------------------------------------------------------------------
The second graph is to compare between Keralam (South India) and Orissa (North eastern India). Third one compares Keralam & Haryana (North western India). All the three diagrams show the strong presence of other limiting factor(s) which are worth studying.
----------------------------------------------------------------------------------------------------------- The emperical analysis given earlier is fine. Conclusions appear to be very much logical. Water contact is essential for hatching of mosquito egg. But my readings and observations indicate that the places where mosquito borne diseases have been prevalent historically need not be wet. Existance of water body in the form of drinking water wells or other ponds are more than sufficient.
The name malaria (of the largest killer of huma history - other than war) is related to mal air (around fowl water bodies) in English language. Its Malayalam (language of Keralam) version malampani is related to mountain since the disease was prevalent only in mountainous areas like Idukki, Wynad etc. The chances of hilly areas being wetter than level or low lying areas ae remote. The reason for malaria to be common in hilly areas in Keralam appears to be mosquito species specific (A.Fluviatills).
Now a days malaria outbreaks occurr in coastal districts. The reason given is that the species that spread malaria there now (A. Stephensi) has preference to coastal habitats. Coastal areas being sandy have minimal/no water logging other than wells. In spite of that, malaria breakes out occassionally - trigger being imported cases.
------------------------------------------------------------------------------------------------------------------
Keralam & Tamil Naadu are neighbouring states of India. Majority of the days are rainy in Keralam. Tamil Naadu is much dryer with much less rain & rainy days. Even then malaria is more common there and most of the imported cases have been reported to be from there! Wetness, I feel, should not be correlated to size of mosquito population and associated diseases.
My feeling is that more than wetness, the factors that govern control or limit the growth of mosquito populationand associated problems are absence/presence of predators and ambient temperature.
The best strategy against mosquito menace (not mosquito) appears to be direct visible assured execution. Chemical methods did not produce sustainable results. Source reduction also appears to be not different.
------------------------------------------------------------------------------------------------------------------
Response to questions of Dec 3rd. Thanks for the complements to the achievements of Keralam's Health Dept. I will try to provide more information about Keralam's malaria control program later on.
The very low figures before 1970 do meanhardly any malaria. To make it clearer I will upload another graph of Keralam alone. This will tell you some more things. Figures before 1970 appear to be very low due to the hugeness of 1976 epidemic.
Till late nineteen fifties India's malaria toll used to be very high. It was at that time that the Govt. of India and World Health Organisation (WHO) jointly executed the half a decade long National Malaria Eradication Project (NMEP) meticulously. By the time of completion of the project the malaria figures of India were brought down to statistical zero and the WHO declared malaria eradicated in India. It is during this & immediately following time that we find the very low numbers of malaria cases.
Once the NME Project was closed everyone slipped into complacency and relaxed comfortably. But since mosquitoe's task was assigned by God Almighty Himself, it could not afford to relax and so earnestly continued its efforts day & night. In a decades time mosquito succeeded intaking the malaria toll back to epidemic proportion. Thats what we see in 1974-76 period.
These are all plain facts visible to anyone. What I wanted you to do was to read between the lines. In spite of the fact that Keralam is much wetter and cooler with widely distributed rains throughout the year over the entire area of the state both the neighbouring dryer & warmer states are having much much more mosquito population and malaria.
Hope you get me. I have much more things to say but even this is too much for one comment and so 'am reserving the rest to the next episode.
Limiting factors other than water in mosquitoe's lifecycle
Deserts,Studies&Emperical analysis.
---------------------------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------------------------------
IF we can make water unavailable to mosquito, we can certainly limit its population. No doubt about that. Doubt is about HOW do we accomplish it? Can we realise a desert like environment in an inhabited place? Will it be affordable? Will it be sustainable? Will it be environmentally acceptable?
I feel the answers to all these questions are in the negative - an emphatic NO.
If the answer is +ve what prevents any one from doing that and saving millions of lives every year.
----------------------------------------------------------------------------------------------------------------
Keralam, Tamil Naadu & Karnataka are neighbouring states of southern peninsula of India sharing common boarders. Keralam has forty four (44) rivers, several lakes & ponds, millions of drinking water wells, numerous perennial streams, large areas of paddy fields that retain water for several months and areawise it is less than one-third of other states. Due to the comfortable climate & vegetation (implying wetness) national as well as foreign tourists renamed Keralam as God's own country.
Tamil Naadu is a much hotter & more dry state compared to Keralam. Karnataka also is similar. With these things in mind if we look at the number of Malaria cases of these states over the three (3) decades one would be tempted (or forced?) to think that more than water or wetness something else is a more important limitins factor. I feel it is ambient temperature.
This does not imply that water is insignificant in mosquito's life-cycle. What is meant is that along with water there are other significant or more significant limiting factors that we should not over-look.
------------------------------------------------------------------------------------------------------------------
-----------------------------------------------------------------------------------------------------------
The emperical analysis given earlier is fine. Conclusions appear to be very much logical. Water contact is essential for hatching of mosquito egg. But my readings and observations indicate that the places where mosquito borne diseases have been prevalent historically need not be wet. Existance of water body in the form of drinking water wells or other ponds are more than sufficient.
The name malaria (of the largest killer of huma history - other than war) is related to mal air (around fowl water bodies) in English language. Its Malayalam (language of Keralam) version malampani is related to mountain since the disease was prevalent only in mountainous areas like Idukki, Wynad etc. The chances of hilly areas being wetter than level or low lying areas ae remote. The reason for malaria to be common in hilly areas in Keralam appears to be mosquito species specific (A.Fluviatills).
Now a days malaria outbreaks occurr in coastal districts. The reason given is that the species that spread malaria there now (A. Stephensi) has preference to coastal habitats. Coastal areas being sandy have minimal/no water logging other than wells. In spite of that, malaria breakes out occassionally - trigger being imported cases.
------------------------------------------------------------------------------------------------------------------
My feeling is that more than wetness, the factors that govern control or limit the growth of mosquito populationand associated problems are absence/presence of predators and ambient temperature.
The best strategy against mosquito menace (not mosquito) appears to be direct visible assured execution. Chemical methods did not produce sustainable results. Source reduction also appears to be not different.
------------------------------------------------------------------------------------------------------------------
Response to questions of Dec 3rd. Thanks for the complements to the achievements of Keralam's Health Dept. I will try to provide more information about Keralam's malaria control program later on.
The very low figures before 1970 do mean hardly any malaria. To make it clearer I will upload another graph of Keralam alone. This will tell you some more things. Figures before 1970 appear to be very low due to the hugeness of 1976 epidemic.
Till late nineteen fifties India's malaria toll used to be very high. It was at that time that the Govt. of India and World Health Organisation (WHO) jointly executed the half a decade long National Malaria Eradication Project (NMEP) meticulously. By the time of completion of the project the malaria figures of India were brought down to statistical zero and the WHO declared malaria eradicated in India. It is during this & immediately following time that we find the very low numbers of malaria cases.
Once the NME Project was closed everyone slipped into complacency and relaxed comfortably. But since mosquitoe's task was assigned by God Almighty Himself, it could not afford to relax and so earnestly continued its efforts day & night. In a decades time mosquito succeeded intaking the malaria toll back to epidemic proportion. Thats what we see in 1974-76 period.
These are all plain facts visible to anyone. What I wanted you to do was to read between the lines. In spite of the fact that Keralam is much wetter and cooler with widely distributed rains throughout the year over the entire area of the state both the neighbouring dryer & warmer states are having much much more mosquito population and malaria.
Hope you get me. I have much more things to say but even this is too much for one comment and so 'am reserving the rest to the next episode.