1.Goldman (6) lists ten monkeys for the Republic of Panama. Four of these are included in this survey.
2.Ateles geoffroyi, the red spider monkey, revealed tertian-like malaria parasites and microfilaria but none of the 24 monkeys showed a trypanosome.
3.Cebus capucinus imitator, the Panama white-throated monkey of Chiriqui, revealed quartan-like malaria parasites, a large trypanosome and microfilaria.
4.Saimiri örstedii örstedii, the Titi monkey of Chiriqui, revealed no malaria parasites but did show a large trypanosome and microfilaria.
5.Alouatta palliata inconsonans, the black howling monkey, revealed trypanosomes but no other blood parasites in the 4 specimens examined.
6.The autopsy examination of these monkeys (Howling monkey not subjected to this examination) revealed adult filaria in large numbers in the abdominal cavity of the red spider and white throated species but no adults were found in any of the cavities of the Titi monkeys.
7.Macacus rhesus, an adult female monkey was inoculated with a total of 5.75 cc. of defibrinated blood from 60 monkeys, 7 red spider monkeys contained malaria parasites and 8 additional ones revealed phagocyted pigment, 3 white throated monkeys contained malaria parasites and 6 additional ones showed phagocyted pigment. This monkey (M. rhesus) has shown no sign of illness, no elevation of temperature and no parasites in the period of six weeks following her inoculations. No trypanosomes have been seen in her blood films although she was inoculated with positive blood from three species: red spider, white throated and Titi monkeys.
8.Nearly all the monkeys showing malaria parasites in the blood or spleen films were infants, juveniles or adult females that were pregnant. No severe infections were found. The thick blood film and films from the spleen and rib marrow were the most valuable films used in this survey. Such films were not used in the Chagres River surveys and this, no doubt, accounts for the failure to find light infections in the adult monkeys.
9.Guinea pigs inoculated with blood from the same three species of monkeys also failed to show a trypanosome infection during the six weeks following the inoculations.
10.The hunters encountered the white throated monkeys 9 times, the red spider monkeys 7 times, the Titi monkeys 5 times and the black howling monkeys 2 times. Whether this represents as many separate colonies of monkeys one can not say, but the monkeys found positive for malaria, trypanosomes and microfilaria were not confined to the captures of any one or two days.
11.The monkey should afford a better animal for research work in malaria than the bird since it supplies a larger volume of blood than the bird, a type of blood cell more closely resembling man and species of plasmodia that are difficult to distinguish from the benign species found in man.
12.Some experiments in the transfer of monkey malaria to man have proven refractory in the Eastern hemisphere yet it would seem proper to repeat this work in our region if an infant monkey with an acute initial infection can be taken alive. Similar efforts with the trypanosomes should be made against the horse.