48 



Sergent (Ed.), Foley (H.) & Vialatte (C). Transmission de 

 Laboratoire du Typhus exanthematique par le Pou. — Arch. Inst. 

 Pasteur Afr. Nord, Algiers, i, no. 3, September 1921, pp. 218-230, 

 5 charts. 



From observations on many cases studied in Algeria, the con- 

 clusions are reached that the bite of adult lice can infect man with 

 typhus. Among the native population, in which this disease often 

 occurs in a somewhat indefinite form, exhibiting special clinical features, 

 it is possible that these virulent lice may have become infected by 

 feeding on cases that exhibit no clear symptoms of typhus. Lice reared 

 on men infected experimentally by lice taken from such a human carrier, 

 transmitted the disease to a monkey, either by subcutaneous or intra- 

 peritoneal inoculation. A healthy monkey was then infected by 

 inoculation of the blood of the diseased one. Infection is hereditary 

 in the louse ; eggs derived from infected lice are capable of transmitting 

 the disease. 



Vialatte (C). Sur des Formes atypiques de Plasmodium praecox 

 {falciparum). — Arch. Inst. Pasteur Afr. Nord, Algiers, i, no. 3, 

 September 1921, pp. 236-239, 1 plate. 



The seasonal oscillation between Plasmodium praecox and P. vivax 

 in Morocco and the Mediterranean and sub-tropical regions has been 

 commented upon by various authors [R.A.E., B, v, 98, etc.]. In an 

 investigation, during the summer-autumn period, of the blood of many 

 malaria cases under treatment in the native infirmary at Kenitra, 

 P. praecox and P. vivax were found in definite association five times, 

 out of 281 cases examined. P. praecox was found in 143 cases, and of 

 these, 35 showed atypical forms. The significance of these atypical 

 forms is not understood. It may be an indication of an association 

 l)etween P. praecox and P. vivax, but the author hardly considers this 

 probable, the morphological characters belonging rather to the yovmg 

 forms of P. vivax, and it seems scarcely likely that, in a whole series 

 of preparations, most of which are taken from long-infected cases, 

 P. vivax should be present only in the form of young schizonts. The 

 hypothesis of double infection with a more or less prolonged latent 

 existence of P. vivax does not seem satisfactory either, for at the time 

 when the first generations of Anophehnes emerge ( in spring and early 

 summer), P. vivax is in the great majority in old cases of infection. 

 The Anophehnes then feeding therefore chiefly acquire the gametes of 

 P. vivax. When, however, the annual epidemic occurs as a result of 

 this Anopheline activity, the majority of infections are found to be 

 of the type of P. praecox. 



On more than one occasion it has been noticed that abnormal forms 

 of P. praecox have appeared during particularly severe outbreaks of 

 malaria, but whether there is any connection between the two rnani- 

 festations it is impossible to say. A similar relation seems to exist 

 between the occurrence of a severe form of piroplasmosis and the 

 presence of atypical forms of the parasite. 



Another hypothesis is that the atypical forms observed represent a 

 transitional stage between P. praecox and P. vivax, but much still 

 remains to be discovered on this subject and further experiment is 

 necessary before any conclusion can be reached, 



