Martin D. Young

Plasmodium vivax Transmitted from Man to Monkey to Man

Blood forms of human vivax malaria infected splenectomized night monkeys (Aotus trivirgatus). Anopheles albimanus mosquitoes transmitted the in fection from a monkey to two human volunteers; parasites and symptoms ap peared 11 days later. Blood forms of vivax malaria from each of the two humans infected other night monkeys.

Failure of chloroquine and amodiaquine to suppress Plasmodium falciparum

Abstract Weekly doses of 300 mg. of chloroquine or 400 mg. of amodiaquine failed to cure or to suppress mosquito-transmitted infections of the Colombia, South American strain of Plasmodium falciparum. Proguanil appeared to cure the two infections treated, and pyrimethamine the three treated, indicating no cross-resistance between them and the 4-aminoquinoline group. Mepacrine (Atabrine) removed the parasitaemias temporarily, but four of six patients treated have relapsed.

Susceptibility of Ateles fusciceps, Ateles geoffroy and Cebu capucinus monkeys to Plasmodium vivax

Abstract Plasmodium vivax infected Panamanian monkeys Ateles fusciceps, A. geoffroyi , and Cebus capucinus . The parasites were from Aotus trivirgatus donors which had been infected originally from human sources. The resultant parasitaemia was relatively high in the Ateles , but low in the Cebus .

Bephenium, a new drug active against human hookworm.

Hookworm (Necator americanus) infections in mental patients constitute a severe problem in many areas because of their severity and the difficulty of effective treatment. The drugs in common use against hookworms ordinarily give poor results with such patients. For a number of years, a search for better drugs has been carried on at this hospital. Recently a preliminary report indicated that bephenium, the generic name of a new series of compounds, i.e., the 2-phenoxyethylammonium salts, was active against certain nematodes, especially the mucosa-dwelling species, parasitic in the gastrointestinal tract of mammals (Copp, Standen, et al, 1958). Burrows (1958) obtained 99.4% clearance of Ancylostoma caninum in dogs and cats using 2-phenoxyethylammonium salts in single doses greater than 20 mgm/kg. Single doses of 20 mgm/kg or less produced results almost as good. The chemical name of the drug used in the current experiments is N-benzyl-N, N-dimethyl-N-2-phenoxyethylammonium chloride. It was furnished to us by Burroughs-Wellcome as B.W.300C55 with the following pharmacological information: The drug apparently is not well absorbed from the intestine since in mice the LD-50 for the chloride, intraperitoneal, is 72 mgm/kg but about 1,000 mgm/kg when the drug is given orally. Rats dosed orally with 500 mgm/kg of the embonate for 9 weeks showed no hematological changes or histological evidence of toxicity. Monkeys given 317 mgm/kg of the chloride and 500 mgm/kg of the hydroxynaphthoate and embonate 5 days a week for 5 weeks showed no significant abnormality in the tissues. When given intravenously the effects of the drug are markedly increased. It produces brief falls in the blood pressure of cats or dogs. Small doses, 0.25 mgm/kg, prolong the action of epinephrine; large doses block the pressor effect. The drug produces some ganglionic blockade and causes a bradycardia. Intense mydriasis was observed in cats, and dogs exhibited salivation and diarrhea. Possible central action is indicated by emetic effects in dogs and respiratory failure. In lethal ranges this appears to be the cause of death. In view of the various studies it appeared justified to test the chloride salt against human hookworm at doses of 20 mgm/kg given orally. The patients were white female inmates of a mental hospital who were selected because they were known to have moderate to heavy hookworm infections. The density of the worm eggs in the feces was determined by the Stoll method, 2 deter-

On the Position of Malarial Parasites with relation to Erythrocytes.

Abstract Eight species of malarial parasites were studied in the living condition by phase contrast microscopy using direct observation and cinemicrography. All of the evidence obtained indicates that the normal parasites lie within the host erythrocyte.