44 



Many other species of Anophelines occur in Brazil, and probably 

 extend into neighbouring countries. The malarial northern provinces 

 of Argentina have a fauna and flora similar to those of Brazil, and a 

 high temperature in summer and autumn, so that their infestation by 

 at least some of the Brazilian species is certain. 



RoDHAiN (J.). Remarques au Sujet de la Biologie de VOrnithodoms 

 moubata. — Ann. Soc. Belize Med. Trop., Brussels, i, no. 1, 

 November 1920, pp. 133-138. 



Further evidence is adduced confirming the author's previous state- 

 ment that the spread of Ornithodoriis moubata is hindered by dense 

 humid forests [R.A.E., B, vii, 151], and this tick has not been found 

 in the forest regions of the Lower Congo. 



It can thrive in all stages and produce fertile eggs when fed on the 

 blood of cold-blooded vertebrates such as snakes and geckos. This 

 fact was ascertained experimentally, but the ease with which the 

 ticks adapted themselves to these hosts seems to indicate that such 

 infestations may occur in nature. 



McCoy (G. \V.). The Problem of Plague in the United States. — Amcr. 

 Jl. Hyg., Baltimore, Md., i, no. 2, March 1921, pp. 182-191. 



The first cases of plague in the United States were recognised in 

 San Francisco in 1900. The experience gained since then shows 

 that even in those communities where very high sanitary standards 

 do not exist the disease does not develop into a disastrous epidemic 

 such as was feared might follow its introduction. The deaths have 

 nowhere been sufficiently numerous to be reflected seriously in the 

 mortality statistics. 



Plague has been found naturally in the following rats and mice in 

 cities in the United States : Mus norvegicus, M. rattus, M. alexandrinus 

 and M. musculus. M. norvegicus predominates in the country as a 

 whole, but in southern ports, M. rattus and M. alexandrinus form a 

 large percentage of the rodent population. All three are concerned 

 in transmission, but their relative importance cannot be stated. Among 

 rural species of rodents or among those usually regarded as city dwellers, 

 but sometimes living under rural conditions, natural infection occurs 

 in Citellus beechyi (ground squirrel) in California, in Mus rattus in 

 Hawaii, and in one species of Neotoma (wood rat) and in a field 

 rodent in Louisiana. Only about seventeen human cases traceable to 

 squirrels have been found since the squirrel origin of plague has been 

 established. The serious aspect of squirrel plague lies in the danger of 

 transmission to urban rats, but as squirrel plague exists in an area 

 at least 150 miles long by 50 miles wide, it is a serious question 

 whether its eradication is justified economically. 



As regards insect carriers, epidemiological data seem to justify serious 

 attention being given "to fleas only. Surveys in San Francisco show 

 Ceratophyllus fasciatus to be the common rat flea, with Xenopsylla 

 (Loemopsylla) cheopis forming only a small percentage of the total ; 

 in southern ports the proportions are reversed. Both attack man, and 

 it has been experimentally proved that either may be a medium for 

 infection. The common mouse flea, Ctenophthalmus musculi, stands 

 alone among common rodent fleas in its refusal to attack man. The 

 common squirrel flea, Ceratophyllus acutus, can carry plague among 

 squirrels and from the latter to other rodents. 



