1.The effects of Atabrine and Plasmochin were observed in a highly malarious area of Calhoun County, Georgia, where a thick blood smear index of school children in six districts showed 80.1 per cent positive for malaria in October, 1932.
2.Because of the high incidence of subtertian malaria, 0.01 gram Plasmochin was given three times a week throughout the malaria seasons of 1933 and 1934, and Atabrine 0.1 gram three times a day (three tablets) for five days, whenever monthly blood smears showed positive, or clinical symptoms developed.
3.Throughout both seasons there was a satisfactory control of gametocyte productions, which it is believed, was due to Plasmochin.
4.Most striking results were obtained in the reduction of malaria infection in the treated area as compared with an untreated district immediately adjoining the treated area. This was due to the effect of Atabrine. At the end of the 1933 malaria season the rate in the treated area was 10.9 per cent, as compared with a rate of 60.3 in the untreated area. In October, 1933, those in the untreated area received full course treatments of Atabrine. there was little variation in the rate during the early part of 1934, but as the season advanced there was an increase to 28.8 in the area originally untreated, whereas in the regularly treated area the incidence was only 8.8 at the close of the season in October.
5.Atabrine has been found particularly effective in the sterilization of carriers. Of 186 positive cases before treatment in May and June, 1933, only 15 were positive in October. Of the 15 cases, only one was positive in July, 1934 and 5 in October. There was, therefore, a reduction of 96.8 per cent at the height of the malaria season in October, 1934.
6.The beneficial effects of both drugs are probably accountable for the lower infection rates among those individuals originally negative in the treated area, as compared with a similar group in the untreated area. Likewise, the percentage of those who were orginally negative and remained negative throughout a two year period was very considerably greater in the treated area as compared with a similar group in the untreated area (table 3). These observations are believed to be of considerable importance in malaria prevention, for they demonstrate the value of carrier control programs in the cure and prevention of malaria.
7.With winter intervening in the temperate zone to aid in malaria prevention, it is believed that the effectiveness of Atabrine and Plasmochin marks an important advance in the control of malaria in this latitude.
8.The short course of treatment necessary, the effectiveness of Atabrine as a schizonticide, and the efficacy of Plasmochin as a gametocide have been proved.
9.The course of treatment with these preparations is short, and this emphasizes the value of these drugs in malaria control.
10.These drugs should prove of great value in lowering malaria infection in connection with drainage projects, or in areas where drainage is not feasible because of costs.
11.Taking into consideration the epidemiology of malaria and cost of drainage, drug control is particularly applicable and advisable in rural areas.
The figures in table 1 have been tested by the usual methods to show that the reduction of malarial infection in the drug treatment area is statistically significant.