M 137
Repetition of Surveys in Wong Chuk Hang Neighbourhood.
Larval surveys were done here from time to time. A large ravine swamp on the outskirts was searched in March and about 2,000 larvae of A. hyrcanus collected. In August practically no Anophelines were found at the head of this swamp which was carefully searched as far as a bund which runs across it and which is 165 yards from the origin. In November this part had been recently trenched for cultivation, very few Anopheline larvae were found. Below the bund, however, the swamp yielded 760 larvae of A. jeyporiensis, 269 A. hyrcanus in three mornings' search by two searchers. Some of this portion had been in rice cultivation and there was water in the rice stubble, larvae of A. jeyporiensis were found in this as well as in the uncultivated swampy portion. In a rushy patch which had been dug up by cultivators numerous larvae of Mansonia and some Taeniorhynchus were found but none in the undisturbed portions, these larvae do not usually appear near the surface as they obtain their oxygen from the roots of plants. During the rainy season adult A. minimus could be obtained from huts in this locality whose ovaries were in an advanced state of development. So far larvae of A. minimus have not been found in numbers in hill streams during that season so attempts were made to ascertain if they could be met with in more quiet waters. Two ponds close to the swamp above mentioned containing vegetation and fed by seepages were searched in July and August, no Anopheline larvae were found. They had also been searched in February and November. In February a few A. minimus larvae were met with and plenty of A. hyrcanus, in November larvae of A. hyrcanus, A. jeyporiensis and a few A. minimus were found. It would seem that larvae of A. hyrcanus and A. jeyporiensis are more plentiful at certain seasons. In December portions of the main stream which flows through the area were searched. In one portion about 700 yards long, lying amongst the hills and receiving tributaries from them, 683 A. minimus larvae, 662 A. hyrcanus, 284 A. maculatus, 10 A. jeyporiensis were obtained. A portion 300 yards long after the stream had left the hills and receiving no tributaries yielded 190 A. hyrcanus larvae and 6 A. minimus.
Repetition of Surveys around New G.C.H. site.
A complete survey had been done during the period of July 7th--August 7th, 1931 over an area of half mile radius, as indicated by the circle on attached map, the centre of the circle corresponding to the site. The only Anopheline larvae found, were those of A. maculatus and these in great abundance. Spleen rate done by the Acting Malariologist resulted in the examination of 150 children and the finding of 22 enlarged spleens, a rate of 14%. Thick and thin blood films were taken from 21 servants living in houses along the Pokfulam Road situated near the site, but no malarial infection was found.
M 137
Repetition of Surveys in Wong Chuk Hang Neighbourhood.
Larval surveys were done here from time to time. A large ravins swamp on the outskirts was searched in March and about 2,000 larvae of A. hyrcanus collected. In August practic- ally
no Anophelines were found at the head of this swamp which was carefully searched as far as a bund which runs across it and which is 165 yards from the origin. In November this part had been recently trenched for cultivation,
for cultivation, very few Anopheline larvae were found. Below the bund, however, the swamp yielded 760 larvae of A. jeyporiensis, 269 A. hyrcanus in three mornings' search by two searchers. Some of this portion had been in rice cultivation and there was water in the rice stubble, larvae of A. jeyporiensis were found in this as well as in the uncultivated swampy portion. In a rushy
rushy patch which had been dug up by cultivators numerous larvae of Mansonia and some Taeniorphynchus were found but none in the undisturbed portions, these larvae do not usually appear near the surface as they obtain their oxygen from the roots of plants. During the rainy season adult A. minimus could be obtained from huts in this locality whose ovaries were in an advanced state of development. So far larvae of A. minimus have not been found in numbers in hill streams during that season so attempts were made to ascertain if they could be met with in more quiet waters. Two ponds close to the swamp above mentioned containing vegetation and fed by seepages were searched in July and August, no Anopheline larvae were found. They had also been searched in February and November. In February a few A. minimus larvae were met with and plenty of A. hyrcanus, in November larvae of A. hyrcanus, A. jeyporiensis and a few A. minimus were found. It would seem that larvae of A. hyrcanus and A. jeyporiensis are more plentiful at certain seasons. In December portions of the main strearn which flows through the area were seached. In one portion about 700 yards long, lying amongst the hills and receiving tributaries from them, 683 A. minimus larvae, 662 A. hyrcanus, 284 A. maculatus, 10 A. jevporiensis were obtained. A portion 300 yards long after the stream had left the hills and receiving no tributaries vielded 190 A. hvrcanus larvae and 6 A. minimus.
Repetition of Surveys around New G.C.H. site.
A
A complete survey had been done during the period of July 7th--August 7th, 1931 over an area of half mile radius, as indicated by the circle on attached map, the centre of the circle corresponding to the site. The only Anopheline larvae found, were those of A. maculatus and these in great abundance. spleen rate done by the Acting Malariologist resulted in the examination of 150 children and the finding of 22 enlarged spleens, a rate of 14%. Thick and thin blood films were taken from 21 servants living in houses along the Pokfulam Road situated near the site, but no malarial infection was found.
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